Approach and methodology of Technoeconomical issues for Koyna let out water utilization
Introduction
Koyna dam is in Satara district of Maharashtra state. It has been constructed about 35 years before. Since then it is giving a very good service to the country. Amongst the other uses the prime importance of this dam that it is very successful Hydroelectric Project in the country. Having a natural site in the Sahyadri ridges on Western Ghats, the catchment provides for a reliable rainfall of about 3700-mm per year. It has a huge storage of 98 TMC at an altitude of 650 m above sea level.
Power generation is being done taking the advantage of fall available. It has IV stages. Total power generation in these stages is about 1920 MW. Potential energy of Waterfall is used to generate the electricity. Initial used water is collected in Kolkewadi dam which is having a capacity of 1.3 TMC at an altitude of 137 m. Further this head is also used for electricity generation. Finally water is let out through tailrace.
Every year, 67.5 TMC water is being let out from Koyna Hydroelectric Project to the Vashisthi River and it then merges to the Arabian Sea. After electric power generation the tailrace water finds its way to sea without any fruitful utilization. In quality it is sweet water and can be treated to drinking water level standards. Quantity is equivalent to cater for the needs of about 2 crore population at the urban standards of 250 lpcd. Drinking water is a prime issue with the Maharashtra state and it has not been solved upto the level of satisfaction. Availability of tailrace water and demand for water in the influence zone of this hydroelectric project is required to be ascertained.
There are alternative uses of water. It is required for drinking. It is required for agriculture and industry. It can be used for development of fisheries, and it can be alternatively used for navigation and recreation. At present huge quantity is just running to sea. To transform it into better usable entity some financial input is required. Naturally, any project has to become financially viable. Equivalent returns are expected.
Level at which the tailrace water is available is about 10.00 m. It meets River, which further merges into sea. This distance is hardly 7 to 8 km.
Sweet water is turned into saline water. This is not suitable for drinking.
Nearest town Chiplun is getting water through Vashisthi River. The demand is much less compared to the available quantity. Diversion to any other area is remote, as level at which it is available is just 10 m. Hence, something different has to be thought of.
Brief details of the existing project.
Koyna dam storage capacity 98 TMC
Average rainfall in the catchment 3700 mm
FRL 657 m
Power generation at the foot of dam 50 MW
Header Tunnel to Pophali length 3800 m
Power generation at Pophali 300 MW
Tailrace water tunnel length upto Kolkewadi 4200 m
Kolkewadi dam FRL 132 m
Kolkewadi dam capacity 1.3 TMC
Headrace tunnel length 1400 m
Power generation at Allore 1000 MW
Tailrace water tunnel start level 22 m
Tailrace water tunnel ends level 10 m
Quantity of tailrace water coming out 67.5 TMC per year
185 mcft/day
5.28 mcum/day
5280 MLD
Urban water requirement in Mumbai urban aglomeration
Urban requirement for drinking water may vary according to size of city and the configuration of industrialization. Present urban supply in Mumbai, Thane etc.is 250 lpcd . Major population in the urban agglomeration of Mumbai, Thane, Kalyan, New Mumbai corporations is 1.5 crores. The prospective population will be 4 crores. Vaitarana is higher level and avialability of water is by gravity near the city. They are reliable sources and time proven for dependability.
Present water supply availability to this aglomeration is from Vaitarana and Bhatsa dams. They are about 80 to 120 km away from these agglomerations. There is a substantial contribution from Barve and Morbe dam. Industrial demand in this agglomeration is very high and it is taken care of by these additional sources.
As far district boundaries are concerned Vaitarana is situated in another region.It is possible to divert water from Vaitarana to Nasik Region. A short length tunnel may be required to be constructed. But considering the
requirement of the Urban agglomeration, Vaitarana stage I,II,III are planned.
If any economical alternative can replace this source it will boost economy of Nasik and Marathwada region.
Tailrace water conveyance to Mumbai urban aglomeration
With the prospective demand of the Urban agglomeration of 4 crores after 30 years will be 4*10^7*300 =12000 MLD. This demand will be generated in a span of 30 years. It has to be planned to be developed well before. Maintaining the existing sources and developing new sources might be in process. It may cost considerable amount. Equivalent quantity is available at the talirace of the project. It is running to sea unutilized. The quantity is available practically at the same ground level. The distance is much more i.e. about 250 km. frictional head will be about 175 m. Total pumping head can be 200 m.
Conveying water to Mumbai Thane Urban agglomeration from Koyna tailrace is a substantial task. Eight no. of 4000 mm dia. pipes will be required.
Approximate cost of pipes can be worked out as following,
Weight of 4000 mm dia. Pipe 15 mm thickness per meter is 1.48 MT
Weight of 250 km, 8 No. pipes 2957880 MT.
Approximate cost Rs. 12423 cr.
Approximate cost including land acquisition, laying, lining, Rs. 18000 cr.
Pumping cost required from Koyna tailrace to 250 Km away and at 200 m head for the whole quantity of water will be as following,
Pumping 5280 MLD at 200 m head will require 244444 HP.
At Rs.5000/HP Installation cost would be Rs.122 cr.
With 20 hr working Energy cost will be Rs. 1.82 cr per day.
Annual pumping cost will be Rs.666 cr.
Assuming 60 days storage for pumping about 11.1 TMC capacity storage will be required. At Rs.2.5 cr per TMC total cost Rs.28 cr will be required.
Approximate capital cost Rs.18000 cr
Rs. 122 cr
Rs. 28 cr
Total Rs.18150 cr
Cost of raw water can be approximately calculated as following,
Capital cost Rs.18150 cr
Annual M&R cost Rs. 1815 cr
Annual Repayment cost Rs. 2270 cr
Energy charges Rs. 666 cr
Estt.cost Rs. 300 cr
Total Annual burden Rs. 5051 cr
Annual water supply 1927200 ML
Cost of water Rs. 26216 per ML
Rs. 26 per 1000 lit.
Cost sensitivity of the components
Cost sensitivity does not seem to be related to pumping or gravity type of system. Major cost is due to cost of pipe. Length involved is much more. Also the diameter required is huge. Tailrace water is available at very low level. Hence local pumping for creating head will also involve similar costing.
Tunnel alternative
Conveying tailrace water through a tunnel of 250 km long and of appropriate size is another alternative to 4m dia. 8 number of pipes. Its economics will have to be worked out. Considering the huge land cost required above ground tunnel may be economical. Approximate size can be about 8 m dia.
For checking this alternative rock strata available, underground water,necessity of lining, etc., parameters will have to be studied.
For taking water from tailrace to Mumbai the possible locations to receive are Pise or at Bhandup water works. If sufficient head is not available then Pise is only alternative.In case sufficient head is available then Bhandup water works can be thought of.
At present for BMC and Thane water lifting point is at Pise. Water from upstream storages of Vaitarana and Bhatsa Dams comes by gravity to Pise.
In case of conveying water through tunnel the needy towns and villages on way can get this water by local pumping. This being raw water necessary treatment will have to be considered.
Alignment of the tunnel can be preferably along the National Highway 17.
It can cover major locations onway. For Mumbai urban agglomeration this is not the only source. However, remaining water will supplement the existing source.
To compensate for the head loss during the transit initial level at the entry of the tunnel will have to be higher. Present tailrace water level is about 10 m. An artificial storage will have to created to pump the water to a suitable location. The best alternative is to use Kolkewadi dam.
Recycling tailrace to Kolkewadi
Pumping water to Kolkewadi is fruitful in view of power generation also. It is nothing but recycling of tailrace water to upsteam in Kolkewadi dam.
Dam FSL is 137.50 m .Tailrace water level is about 15 m average.
Lift involved is 122.5 m.
Quantity is 5280 MLD or 61111 lit per sec.
HP required 140915 HP
Annual energy cost will be 384 crores.This is quite a huge amount. Its economics will have to be studied.
For this purpose both the alternatives will be required to be studied in details.
Generation capacity
Phase I & II 65 MW 4 No. 260 MW
75 MW 4 N0. 300 MW
20 MW 2 MW 40 MW
Phase III 80 MW 4 No. 320 MW
Phase IV 250 MW 4 No. 1000 MW
Total 1920 MW
Daily 1920 MW generation capacity can get Rs.77 lakh per day and about Rs.280 crores per year at minimum rates. Prima facie pumping tailrace water does not seem to be practical.
Power generation is very important as far as the State income is concerned. It is important from the industries point of view also. Hence, any change in the infrastructure will have to be weighed against all economical angle.
Rough costs of pumping tailrace water either to Kolkewadi dam or to Mumbai through conveyance system show that they are not economical as they involve comparatively much more cost in the maintenance itself. If it is absolutely required then it should be viable only for the commercial utilization. Rate for commercial utilization is normally 4 to 5 times more than the domestic rate for water.
Further the capital cost required for conveying the water to Mumbai is huge and its financial analysis itself is a job. Lot of data will be required as far as the future industrial development is concerned. Similarly private sector involvement needs to be assesed.
Availability of power and availability of water in the Kokan area can be further developed and industries can be attracted to this area. It is also required to be verified, that non-forest area and their present land use pattern
marks availability of land for industrial purpose. Presently the communication to Mumbai has become easier because of Kokan Railway.
With all these parameters planning of water base industry has to be identified.
Overall Quantity balance
Koyna dam is a multiutility dam. It is useful for Power generation, Irrigation, Drinking water, flood control and number of other purposes.
As far power generation is concerned water balance seems to as following,
Koyna capacity 98 TMC
Kolkewadi capacity 1.3 TMC
Total capacity 99.3 TMC
Tailrace water let out 67.5 TMC
% of tailrace water 68 %
Approximate cost of let out water at the Irrigation normal rates is Rs.25 cr.
per year.
As far as the quantity of tailrace water running to sea is substantial compared to the overall storage. Considering to the other uses of water it is huge. Particularly, referred to drinking water supply this quantity is more cognizable. Quantity running to sea is sweet water. In the fair season the water is available for drinking in this area. However, in the summer season the water is scarce in the rural wadies and in some parts of the urban areas.
Tailrace water mixing effects
Tailrace water is let out in the River Vashsthi, which in turn reaches to sea. This process is continued for about 35 years. The quantity is varying according to generation activity. River Vashsthi has absorbed these changes in its course to sea. Accordingly the the banks and the bed is readjusted .Any change in the pattern will have to be studied as to how it is getting reflected in the set pattern of the river. It is quite likely that salinity of water due to sea intrusion has been substantially reduced due to addition of tailrace water in the river course. The stretch of sweet water zone in balance with sea water has to be identified.
Tourism and navigation
The level at which the tailrace water is mixing into the River Vashisthi is about 10. The stretch of combined flow is about 45 km upto sea water. The river water in the summer is comparatively less. Tailrace water is fairly constant over the period. Hence, river is having a flow in the summer period. This flow has become a partial means of conveyance. It is not developed fully. It can be systematically developed. River banks can be strengthened and developed for tourism. It can be a systematic master plan to develop as a tourist attraction center. Navigation for tourism purpose is not yet established. It also needs attention. The rough cost estimates and planning strategy is to be detailed out. Though it is planning area of civil engineers, planning and modifying structures as well as hydraulics is a specialized area. It can better be dealt with by Landscape Architects. Gross economics can be worked out while giving shape to the tourism center. It may include navigation. Development of huge parks and sloping gardens will be planning canvas for the architects having a wide angle, with lots of other attractions for the tourists. When the cost of water itself is about Rs.25 cr per year, such a development will need a sizeable amount. However, it will create a job potential for local youth.
Industrial demand
In Raigad district two major industries are developed. One is electrical power generation in Dabhol. Other one is petrochemical industry. After full development they will require major quantity of water. This quantity can be provided to them at reasonable rates. They can put a major treatment facility and provide a surplus capacity. They can utilize this surplus capacity by planning a regional scheme of nearby towns and villages. They can select a total taluka for such a purpose. They can give services and get the revenue also. As they will be a major benefit to the nearby population Irrigation may apply the rates for the domestic use. Planning in such a way will be fruitful to all concerned. Electric power generation will be commissioned at Dabhol within 1 to 2 years. It was stopped for a period,but the issues are resolved now. When the main industry is commissioned the other satellite industries are also sure to flourish. They will also need water.
It is essential to asses the future plans of Industrial Deptt. It is necessary to know the scope to develop the industries in this area. Nearness to Mumbai and easy connections by Kokan railway can identify major inputs by the private sector. Availability of water has to be spelled out. It will give further inclination to the intending industries.
Agricultural sector
Raigad, Ratnagiri and Sindhudurg districts are known for rice growing. In rainy season the rainfall is substantial and hence, there is no question of water requirement for agriculture. Land available for agriculture is mainly on slopes and not large pieces. Quality of soil available does not permit to take rabbi crops fruitfully. Water is not available in plenty to the rabbi crops. Lift irrigation facilities are not in common. Hence, the prospective farmers take some support varieties. Even with available water change in crop pattern seems to be difficult.
Instead, with given facilities farmers can be encouraged to evolve fruit cultivation. Land permits such cultivation. Environment also suits for Mango, coconut, cassuenuts, papai and others. Agricultural produce will have to be marketed by organized sector. Food processing industries also can emerge in this area. This area has good communication with Mumbai area at the personal level. Its institutionalization is necessary. Cash flow increase in this area is very essential. Labour is available but trained or skilled inputs are required.
Use of water for agricultural purpose at the personal level seems to be difficult. Organized sector can take up such farming. It may become profitable. Cooperative sector is not flourished in this area. At least in the Raigad district revenue land is available for farming by the organized sector.
An information about these developments will have to be considered from the concerned department. Prospective demand for water and usability of tailrace water will have to be worked out. Present land use under cultivation, agricultural proceeds from these areas, present use of water etc. is to be collected and analyzed.
Cash crops in this area are lagging. Farmers are marginal. In the heavy rains farming is painstaking. Change of pattern is not traditionally accepted. Hence, organizational support is expected. Financial capacity is very meager. From the social angle, water availability be extended to the farmers.
It is difficult to expect the cash returns from the agricultural sector in this area unless some different strategy is adopted.
Koyna stage V and Kolkewadi acting as balancing storage
In stage IV water is taken from Dam to power station using new technique. It has been successful. It has added 1000 MW power generation. It is encouraging technique and it can be repeated. Power generation may increase using the available water. The important aspect in this regard is that whether this possible stage is to add in the tailrace water quantity. If tailrace water is being increased then its quantification is necessary. It should be taken into account.
In case of stage III to stage stage IV transformation, record is to be verified as to what quantity is added to the tailrace water, by each stage. It is also likely that ex-Kolkewadi there may not be any change in the tailrace water. It will ensure that water quantity in the main dam is utilized in such a way that power generation is enhanced using same quantity of water.
In such a case, if stage V really comes, then Power generation will be balanced, even if the ex-Kolkewadi power generation is stopped. In that case tailrace water will be available at 137 m. Kolkewadi will act as the balancing tank. Any distributions from that level will become easier and economical. Power generation and utilization of water in the tailrace will have to be economically evaluated. Kolkewadi acting as a storage tailrace water running to sea will be reduced. Other utilization will be given priority and balancing storage of 1.3 TMC in the dam will be used as per necessity.
Other uses can be for drinking water, tourism, navigation and combination of all. The uses have seasonal importance. They can be identified accordingly. Water requirement for each use can be calculated and reserved for particular purpose. Obligatory letting out can have control.
Diversion of tailrace water of stage II
Tailrace water from stage II reaches to Kolkewadi dam. It is at higher level. Approximate level is 137 m. A contour tunnel at this level can be taken on both the sides of the outlet. The capacity of canal can be decided as per the demands. For this purpose the prospective demands can be calculated. These may include demand for industrial, agricultural, and for drinking water purpose.in the area through which it is passing. Topographical study is necessary for the feasibility of this proposal initially.
Record for the stage wise tailrace quantity can be verified. Stage IV has come into operation for last 6 years. Changes in the tailrace water quantity are to be noted. Fall involved in both the cases is different. Velocity at which they are approaching may be different. Similarly the residual energy level in the water flow will be different. Combination effects are to be verified.
A study will have to be made whether there is any additional site for the construction of dam of equivalent capacity of Kolkewadi, to accommodate for any additional tailrace water coming in future after completion of possible Stage V
If such a site is available towards south side, part tailrace water can be taken to this area. Storage at this place may have advantage to divert water to Warna basin either by a tunnel or by pumping. The connected area on the otherside of the ridge is drought prone. Some benefits can be given to this area. A study shall have to done as to whether this technically feasible. From Kolkewadi to possible dam site, it is to be checked whether contour tunnel conveying is technically possible. Its economics is to be studied. Detailed maps including the land use pattern shall have to studied. During this range if there is a possibility of any tapping for drinking water, it has to be verified.
Recent heavy rainfall and floods
Recent heavy rains in July 2005 have created a typical situation. In June 2005 there were a crisis of electricity. Rains were somewhat delayed. Every body was waiting for mansoon. In July last week heavy rains poured in this area. Mumbai rains created the record pouring of 946 mm in a day. Similar was the situation in Kokan area. In Koyna catchment area heavy rainfall was contiued and dam was filled to 95 % capacity. Letting out of water from dam was unavoidable. Few days before power generation was required to stopped for want of inadequate quantity of water in the dam. However, situation changed with heavy rainfall. River Vashisthi was flooded. Water was spreading in the areas and in the Chiplun city. In such a case addition of tailrace water in the River Vashisthi would have worsened thew situation of floods.
Collector Ratnagiri reviewed the situation. He declared that tailrace water to be stopped for mixing in the River Vashisthi. For this purpose power generation was required to be stopped. Importance of power generation was already known. But situation was such, that generating power at the cost of floods was not making any sense. Hence, Collector took a correct decision to stop the relevant power generation so that tailrace water can be stopped from mixing in the River Vashisthi.
Decision taken by the administration speaks about important aspect. Power generation is important. State was going through the energy crisis. But the inordinate situation created by nature overshadowed the importance of power generation. It was stopped for a period. Letting out water in already flooded river was expected to be more criticized. Power generation was stopped as letting out of water was required to be stopped. It becomes clear that these two issues can be delinked. Power generation has its own importance. At the same time let out water has also a potential and it can be saved and used in other fruitful way.
Decision was taken at the District level and not at the Govt. level. This indicates that the decision was natural and distinct. Technical authorities
are expected to review the situation. It is important to consider the views of Administration in this respect. These authorities might have crystallized some ideas. Technical and financial viability will have to be studied in details.
Administration has to face the difficulties regarding drinking water supply in the summer period in their area of control. Every year tankers are required to be engaged. Practically all the villages and wadies have the source in fair season. These sources deplete in summer and the problem starts. They get replenished in rainy season. Situation is created every year. The permanent solution is visualized in the let out water from the tailrace. Since it is not felt economical, the proposal does not take shape. A systematic study in this regard is required. It will need the discussion with the concerned officers in the Districts. Alternative expenditure figures are required to be taken into account.
Opinion of selected group of local dignities in Kokan area
The issue of letting out of tailrace water is being in the limelight for last 35 years. Local residents in this area might have a good apprehension of the issue. They may have some useful ideas in their mind. They might not have opened out because of the feasibility grounds. All such issues will have to taken for consideration and checked roughly for the technical and financial feasibility. Their economics can be openly discussed.
No wastage parameter
The principle adopted for the industry for identifying the fullfledgeness is that there should not be any wastage and all the byproducts are also utilized.
The same Principle shall have to be utilized, in case this tailwater issue. Whatever is being wasted is worth Rs.25 cr per annum. This cost is calculated considering the domestic rate for raw water at Rs.1.30 per 10000 lit. When it made available to Mumbai raw water rate rises to Rs.4 per 1000 lit. Cost involved at this rate for let out quantity comes to Rs.771 cr per year. In addition, for it has not been utilized for specific uses, Govt. has to put in about Rs. 5 cr per year, i.e for scarcity purposes.
Till the tunnel conveyance system is materialized power generation in stage III will continue and to that extent tailrace water will reach the Sea.
Irrigation Deptt. has elaborately checked the issue. May be because financial constraints proposal might not have taken shape. However, lots of developments have taken place in last 35 years. Parameters have changed. In general, it can be seen that the issue is identified as a separate project. It is multidimensional. Economic feasibility will be dependent on considering all the issues.
Prima facie it is a high cost project. Raising of funds will be major issue. Apart from the State Govt,. beneficiaries also will have to contribute. External funding may also be required. Initially development of tourism can be taken on priority and then main project be processed. Initial cost in such development will be comparatively much less but the benefits will be area specific.
Evaluation and arriving at a viable proposal
Kirloskar Consultants have in-house expertise to deal with such issue and
can study all the parameters. However, considering the multi-angles of this issue some local expertise can be involved.
The team may visit the sites and also discuss the parameters with field staff.
The discussions will also be held with officers of the other concerned departments. Similar issues tackled with in other countries will also be taken cognizance of through web sites.
Activity-wise schedule of man-days involved is enclosed herewith for ready reference..
Sunday, February 24, 2008
OPTIONS FOR MUNICIPAL WATER SUPPLY
OPTIONS FOR MUNICIPAL WATER SUPPLY
The present policy of Govt. of Maharashtra and in turn of MJP is to execute and hand over the schemes to local bodies, for operation and maintenance i.e. urban schemes are handed over to MC and corporation, while rural schemes are handed over to GP and ZP. The demand for scheme is received from the local body and at that time they liberally resolve for raising and repayment of loans required, for the scheme. The Water Supply schemes are entitled for GIA of 25%, 40%, 50% and 90% respectively for Municipal schemes respectively for A class/Corporation, B class and C class. C class Municipal councils with less than 20,000 population are entitled for 100% GIA till recent past, which is now decreased to 90%. In addition, the present policy is to give 100% grant in aid for the cost of pipe lines beyond 3km/5km/8km respectively for C class MC, B class MC, A class councils/corporation. The LPCD considered till recent pas was quite liberal and design period was 30 years. This lead to administrative approval of large size municipal water supply schemes with distant sources. Normally, this source being irrigation dams and proposed under reliability considerations. The MC/Corporation chose to demand for such size schemes and also used to resolve and accept liberally for raising and repayment of loans for these big sized schemes for pleasing/impressing people by showing that they have succeeded in bagging the water supply scheme for their town with large amount of GIA.
Most of these schemes are already under execution and are at various stages of progress. Now it is being seriously thought that these schemes are not economically viable, in view of present financial status of MC. Due to poor water rates and por recovery by local bodies, the loans raised by these MC through MJP are not returned by them and most of them are in heavy financial arrears with MJP. For resolving this situation following administrative, financial, technical, steps are considered to be efficient.
The CPHEEO manual is presently specifying a uniform rate of 70 LPCD should be considered for calculation of demand for town of all sizes. Even it says that 30% population which is sufficient. These things put together the water rate comes to 61 LPCD for total population. CPHEEO manual says that additional demand for school, colleges, hostels, picture halls, offices, hospitals, lodges hotels, building under construction should be considered. Calculation of demand for these amenities is normally forgotten by consultants while framing Water Supply schemes, being difficult to compute and the scheme gets framed to 61 LPCD Water Supply which is obviously very low, especially for the town with 50 thousand population or more. It is furthering more difficult to project demand for the year at the end of design period for these amenities. The design criteria of 30 years are correct and should not be considered for reduction. So as to avoid duplication of lines from distant sources in a short period. It is worth while to note that capacity of pipeline increase in proportion to cross sectional area of the pipeline (D) 2 while the cost increases in proportion with the diameter. So obviously maintenance of two lines is much costlier.
Recent policy changes indicate that small size schemes are more economical and can be better handled by the lower class municipal councils. If the nearby source is sufficient for demand of 10-15 years then only the size of the scheme should be reduced, suiting to the availability of water all that source. In short once we had gone to an extreme end of large sized scheme and now going to the another extreme end to small scheme, need to be avoided.
In urban distribution system the residual heads are normally specified as 12 m as 17 m, while the ESR staging of old ESR’s is around 14 m and there is a temptation of providing another ESR with the same staging. If the tail end is flat or nearing flat, and the available heads from LSL of reservoir to negotiate with frictional losses is very less. Normally the designs are being done with use of computers and these designs do not show the velocity in the pipelines, which ultimately leads to the choosing of unduly higher diameters. This leads to increase pipe volume, which further leads to more unequal distribution due to quicker emptying of ESR. The appropriate solution is to increase the staging height of ESR and choose it at Proper location.
If a distribution system is designed with 61 lpcd especially where the population is already enjoying 80 lpcd or more and is claiming for scarcity of water due to unequal distribution in the system then the actual distribution is likely to be in range of 40 to 80 lpcd for the town with fair topography. For the town with unfavourable topography the actual distribution of water may be something like 30 to 80 lpcd. When the size of the town increases beyond 50,000 the actual distribution of water becomes further more unequal and such distribution leads to discontents and which leads to decrease in willingness to pay and eventually to poor recovery. On paper the scheme gets 61 lpcd while the scheme has failed.
The ward wise forecast of population for the design year is not rationally done in most of the cases. If the increase in population is accepted to be 2.5 times in 30 years, then population of wards in core area will not increase by 2.5 times and may increase by 0 to 50% while the population in the wards at the periphery will increase more than 2.5 times. Non consideration of this aspect leads to unduly large diameters in the core area and unduly small diameters at the periphery. This leads to demand of laying fresh lines from ESR and non laying of them leads to availability of less lpcd at the expanding ends.
Presently providing of meters is avoided on the grounds of cost of repairs, reading, billing. By tapping of sources at longer distance the cost of wasted water is increasing and hence the policy of metering needs to be reviewed. Metering is the effective method for computing unaccounted water and eventually for its reduction. The level of service can be more rationally ascertained because the acceptation of the users in terms of lpcd is very high, while Municipal Corporations/Government wants to supply less lpcd for restricting present investment. Once the repair of the meters, maintenance of the spare parts were big issues, but with present general advancement in technology, these issues needs re-evaluation.
Now a days agencies which can provide, maintain, read the meters and generate bills are available, and need to be encouraged. The feeling of Municipal Council is to hand over the complete system to such agencies who can maintain and repair the system including collection of revenue. This is not practicable because of present poor water rates, improper design of available distribution system, heavy subsidy from other sources of Muicipal Councils, to water supply and large strength of employees with higher pay scales. Instead of attitude of getting rid of total activity, the present maintaining agency has to take a rational view of entering in contract with such manufacturing agencies for only providing, maintaining and reading meters with generation of bills for a sizable period of 5 years, while the collection shall be retained with the Municipal Councils. This will ensure more equitable water supply and more increase willingness to pay, so that Municipal council can increase the water rates annually, decreasing cross subsidy and making the scheme self sufficient in a reasonable period of 2 to 3 years. The desire of making the scheme instantly self sufficient, leads to never making of scheme self sufficient.
If we want to hand over a scheme to private agency including collection then it is necessary to give option to the agency for choosing the required numbers of employees with a right to reject notorious employees. In short transferring of employees as per seniority is not a proper solution. So also the agency should have a right to depart with few employees whom they considered to be inefficient or notorious, even after entering in the agreement.
The contract should have a provision of making payments for the service rendered by them, while the revenue collected by agency shall be deposited with Municipal Council on day to day basis.
Alternatively the distribution of an individual ESR of a city be isolated and given on maintenance contract, where the meters of specified make are purchased and provided by the consumer and the contracting agency is required to maintain distribution system along with repairs of meters with or without collection of revenue. The contract has to charge to consumers for the repairs of meters, for which a schedule shall be made available. Only 3 or 4 makes of water meters with model numbers should be specified, so that repairing becomes easy. The maintenance contract of distribution system can have various items of repairs for a better control of service level, and removing risk factor to the contract. It should also have appropriate penal clauses to reduce the repair timings.
ZONING OF DISTRIBUTION SYSTEM
Distribution network is available for any city is required to be presented on the map of a proper scale. All storages are required to be shown on the map. All levels are also required on the map. Contours will give better idea of the possible pressures in the system.
Distribution system can be old one. After a period there can be addition to the system in the same area or it can be newly developed area. Age of the pipelines reduces the C-value of pipe material and hence the carrying capacity. With the increase in demand number of connections on old lines becomes more than its capacity. This reduces the pressures in the system. Consumers try to get accustomed to the changing situation but somehow dissatisfaction amongst the consumers begin to build up.
Dissatisfaction of consumers reflects in two ways,
a) Delaying or non-paying tendency
b) Yielding maximum water from the connection by tapping at lower levels.
In any case the system suffers. It may receive lesser revenues and also it becomes prone to pollution externally.
Improvements in the system are possible. But these improvements are cost intensive. Financially local bodies are weak and contributing for improvements is not easy for them and hence administratively it is difficult to sanction the improvements scheme.
To some extent, this difficulty can be solved, by resorting to zoning. New construction of ESR is not possible, but a pipeline can be laid directly from existing ESR to the required are without any tapping and can be directly connected to the main line of that area. In turn this line serves the purpose of construction of new ESR in that area. Pressures get improved and Consumers are benefited.
Zone of influence of any ESR
Let, R be the radius of zone with ESR as center.
At all the points on the circumference there is a required pressures say, 12 m for two story habitations.
Let maximum head loss upto the circumference be hf.
Height of ESR should be 12+hf. = H
Assume, that connections start from D m from center of ESR Then zone of influence is 0.785* (R^2-D^2)
Assume head loss in the system as 4 m / km.
For 2 km, hf = 2*4 = 8m
H = 12+8 = 20m
R = 2+D = 2 + 0.3 = 2.3 km. Assuming D = 0.3 km,
Zone of influence = 0.785* (2.3*2.3-0.3*0.3) = 0.785*5.2 = 4.082 sqkm
Zone of influence can be increased by increasing D by laying feeder main starting from the ESR directly. This becomes easy when the ESR has been provided with additional outlet for the future. Increased zone of influence can be catered differed timings. With old systems effective R will be lessened after a long time. In such cases multioutlet systems can work better with arrangement of overlapping zones of influences.
When demand is increased ESR level gets depleted rapidly. Rate of inflow proves to be less than rate of flow outgoing. This indicates higher peak factors are operating. Duration of flow of water through ESR reduces as far as effective operation is concerned. As flow of water will still continue but the level of water in the tank will not be maintained in the tank itself. This is an indication of depressurization in the system. It also indicates that the lines downstream are not running full. In this case immediate control should be to control the main valves and control the branches which are dragging water more by virtue of their levels.
Improvements with use of booster pumps, shafts and master pieces
Improvements can be done by adopting booster pumping. It uses the same quantity of water but it is further energized by using pumps. Consumers are satisfied with the increase in pressure.
Boosters can used in the form external source such as borewells or tubewells and direct pumping into the system. External water quantity may be very low compared to distribution flow, but it increases the pressure very effectively.
It is convenient to think of erecting a shaft of appropriate diameter and height in the system for getting a better control of pressures. The shaft can get water either externally or it may get water from the existing ESR through a separate feeder. External supply can be using pumps on the bore well or tube wells.
Conceptually shaft is nothing but an ESR operating with its lowest water level in the outlet pipe and not in the container. Incoming water is equal to outgoing. In the shaft there is central pipe having a small diameter than the outer pipe having a comparatively bigger diameter designed to carry the demand flow of the zone of influence. Both the concentric pipes shall be in mild steel so that the weight of shaft assembly to be erected shall be easy to handle. Shaft can be erected on a good pedestal of masonry or concrete of appropriate height. Annular space between the vertical pipes acts as a container and it can be provided with multioutlets for ensuring zoning. Pressure building characteristics are better in respect of shaft compared to ESR. Shafts are better suited where the zone to be supplied is comparatively at lower ground levels.
When the pressures in the distribution system are low and time duration of supply is also comparatively less low lying areas are benefited more in comparison with the higher level areas. Retained duration of water supply in the system in the lower areas is more as well as the pressures. Consumers in higher areas are aggrieved of getting less supply of water and with lesser pressures. In such cases, select the mains of higher and lower areas. For balancing the heads introduce a smaller diameter metallic pipe having a length of minimum 20 times diameter of main pipe and ensure fixity concentrically by sealing the annular space by cement mortar. This is a trial and error method and within one or two trails exact diameter of small pipe is found out. This piece of pipe is known as ‘master piece’ and it functions most satisfactorily.
The present policy of Govt. of Maharashtra and in turn of MJP is to execute and hand over the schemes to local bodies, for operation and maintenance i.e. urban schemes are handed over to MC and corporation, while rural schemes are handed over to GP and ZP. The demand for scheme is received from the local body and at that time they liberally resolve for raising and repayment of loans required, for the scheme. The Water Supply schemes are entitled for GIA of 25%, 40%, 50% and 90% respectively for Municipal schemes respectively for A class/Corporation, B class and C class. C class Municipal councils with less than 20,000 population are entitled for 100% GIA till recent past, which is now decreased to 90%. In addition, the present policy is to give 100% grant in aid for the cost of pipe lines beyond 3km/5km/8km respectively for C class MC, B class MC, A class councils/corporation. The LPCD considered till recent pas was quite liberal and design period was 30 years. This lead to administrative approval of large size municipal water supply schemes with distant sources. Normally, this source being irrigation dams and proposed under reliability considerations. The MC/Corporation chose to demand for such size schemes and also used to resolve and accept liberally for raising and repayment of loans for these big sized schemes for pleasing/impressing people by showing that they have succeeded in bagging the water supply scheme for their town with large amount of GIA.
Most of these schemes are already under execution and are at various stages of progress. Now it is being seriously thought that these schemes are not economically viable, in view of present financial status of MC. Due to poor water rates and por recovery by local bodies, the loans raised by these MC through MJP are not returned by them and most of them are in heavy financial arrears with MJP. For resolving this situation following administrative, financial, technical, steps are considered to be efficient.
The CPHEEO manual is presently specifying a uniform rate of 70 LPCD should be considered for calculation of demand for town of all sizes. Even it says that 30% population which is sufficient. These things put together the water rate comes to 61 LPCD for total population. CPHEEO manual says that additional demand for school, colleges, hostels, picture halls, offices, hospitals, lodges hotels, building under construction should be considered. Calculation of demand for these amenities is normally forgotten by consultants while framing Water Supply schemes, being difficult to compute and the scheme gets framed to 61 LPCD Water Supply which is obviously very low, especially for the town with 50 thousand population or more. It is furthering more difficult to project demand for the year at the end of design period for these amenities. The design criteria of 30 years are correct and should not be considered for reduction. So as to avoid duplication of lines from distant sources in a short period. It is worth while to note that capacity of pipeline increase in proportion to cross sectional area of the pipeline (D) 2 while the cost increases in proportion with the diameter. So obviously maintenance of two lines is much costlier.
Recent policy changes indicate that small size schemes are more economical and can be better handled by the lower class municipal councils. If the nearby source is sufficient for demand of 10-15 years then only the size of the scheme should be reduced, suiting to the availability of water all that source. In short once we had gone to an extreme end of large sized scheme and now going to the another extreme end to small scheme, need to be avoided.
In urban distribution system the residual heads are normally specified as 12 m as 17 m, while the ESR staging of old ESR’s is around 14 m and there is a temptation of providing another ESR with the same staging. If the tail end is flat or nearing flat, and the available heads from LSL of reservoir to negotiate with frictional losses is very less. Normally the designs are being done with use of computers and these designs do not show the velocity in the pipelines, which ultimately leads to the choosing of unduly higher diameters. This leads to increase pipe volume, which further leads to more unequal distribution due to quicker emptying of ESR. The appropriate solution is to increase the staging height of ESR and choose it at Proper location.
If a distribution system is designed with 61 lpcd especially where the population is already enjoying 80 lpcd or more and is claiming for scarcity of water due to unequal distribution in the system then the actual distribution is likely to be in range of 40 to 80 lpcd for the town with fair topography. For the town with unfavourable topography the actual distribution of water may be something like 30 to 80 lpcd. When the size of the town increases beyond 50,000 the actual distribution of water becomes further more unequal and such distribution leads to discontents and which leads to decrease in willingness to pay and eventually to poor recovery. On paper the scheme gets 61 lpcd while the scheme has failed.
The ward wise forecast of population for the design year is not rationally done in most of the cases. If the increase in population is accepted to be 2.5 times in 30 years, then population of wards in core area will not increase by 2.5 times and may increase by 0 to 50% while the population in the wards at the periphery will increase more than 2.5 times. Non consideration of this aspect leads to unduly large diameters in the core area and unduly small diameters at the periphery. This leads to demand of laying fresh lines from ESR and non laying of them leads to availability of less lpcd at the expanding ends.
Presently providing of meters is avoided on the grounds of cost of repairs, reading, billing. By tapping of sources at longer distance the cost of wasted water is increasing and hence the policy of metering needs to be reviewed. Metering is the effective method for computing unaccounted water and eventually for its reduction. The level of service can be more rationally ascertained because the acceptation of the users in terms of lpcd is very high, while Municipal Corporations/Government wants to supply less lpcd for restricting present investment. Once the repair of the meters, maintenance of the spare parts were big issues, but with present general advancement in technology, these issues needs re-evaluation.
Now a days agencies which can provide, maintain, read the meters and generate bills are available, and need to be encouraged. The feeling of Municipal Council is to hand over the complete system to such agencies who can maintain and repair the system including collection of revenue. This is not practicable because of present poor water rates, improper design of available distribution system, heavy subsidy from other sources of Muicipal Councils, to water supply and large strength of employees with higher pay scales. Instead of attitude of getting rid of total activity, the present maintaining agency has to take a rational view of entering in contract with such manufacturing agencies for only providing, maintaining and reading meters with generation of bills for a sizable period of 5 years, while the collection shall be retained with the Municipal Councils. This will ensure more equitable water supply and more increase willingness to pay, so that Municipal council can increase the water rates annually, decreasing cross subsidy and making the scheme self sufficient in a reasonable period of 2 to 3 years. The desire of making the scheme instantly self sufficient, leads to never making of scheme self sufficient.
If we want to hand over a scheme to private agency including collection then it is necessary to give option to the agency for choosing the required numbers of employees with a right to reject notorious employees. In short transferring of employees as per seniority is not a proper solution. So also the agency should have a right to depart with few employees whom they considered to be inefficient or notorious, even after entering in the agreement.
The contract should have a provision of making payments for the service rendered by them, while the revenue collected by agency shall be deposited with Municipal Council on day to day basis.
Alternatively the distribution of an individual ESR of a city be isolated and given on maintenance contract, where the meters of specified make are purchased and provided by the consumer and the contracting agency is required to maintain distribution system along with repairs of meters with or without collection of revenue. The contract has to charge to consumers for the repairs of meters, for which a schedule shall be made available. Only 3 or 4 makes of water meters with model numbers should be specified, so that repairing becomes easy. The maintenance contract of distribution system can have various items of repairs for a better control of service level, and removing risk factor to the contract. It should also have appropriate penal clauses to reduce the repair timings.
ZONING OF DISTRIBUTION SYSTEM
Distribution network is available for any city is required to be presented on the map of a proper scale. All storages are required to be shown on the map. All levels are also required on the map. Contours will give better idea of the possible pressures in the system.
Distribution system can be old one. After a period there can be addition to the system in the same area or it can be newly developed area. Age of the pipelines reduces the C-value of pipe material and hence the carrying capacity. With the increase in demand number of connections on old lines becomes more than its capacity. This reduces the pressures in the system. Consumers try to get accustomed to the changing situation but somehow dissatisfaction amongst the consumers begin to build up.
Dissatisfaction of consumers reflects in two ways,
a) Delaying or non-paying tendency
b) Yielding maximum water from the connection by tapping at lower levels.
In any case the system suffers. It may receive lesser revenues and also it becomes prone to pollution externally.
Improvements in the system are possible. But these improvements are cost intensive. Financially local bodies are weak and contributing for improvements is not easy for them and hence administratively it is difficult to sanction the improvements scheme.
To some extent, this difficulty can be solved, by resorting to zoning. New construction of ESR is not possible, but a pipeline can be laid directly from existing ESR to the required are without any tapping and can be directly connected to the main line of that area. In turn this line serves the purpose of construction of new ESR in that area. Pressures get improved and Consumers are benefited.
Zone of influence of any ESR
Let, R be the radius of zone with ESR as center.
At all the points on the circumference there is a required pressures say, 12 m for two story habitations.
Let maximum head loss upto the circumference be hf.
Height of ESR should be 12+hf. = H
Assume, that connections start from D m from center of ESR Then zone of influence is 0.785* (R^2-D^2)
Assume head loss in the system as 4 m / km.
For 2 km, hf = 2*4 = 8m
H = 12+8 = 20m
R = 2+D = 2 + 0.3 = 2.3 km. Assuming D = 0.3 km,
Zone of influence = 0.785* (2.3*2.3-0.3*0.3) = 0.785*5.2 = 4.082 sqkm
Zone of influence can be increased by increasing D by laying feeder main starting from the ESR directly. This becomes easy when the ESR has been provided with additional outlet for the future. Increased zone of influence can be catered differed timings. With old systems effective R will be lessened after a long time. In such cases multioutlet systems can work better with arrangement of overlapping zones of influences.
When demand is increased ESR level gets depleted rapidly. Rate of inflow proves to be less than rate of flow outgoing. This indicates higher peak factors are operating. Duration of flow of water through ESR reduces as far as effective operation is concerned. As flow of water will still continue but the level of water in the tank will not be maintained in the tank itself. This is an indication of depressurization in the system. It also indicates that the lines downstream are not running full. In this case immediate control should be to control the main valves and control the branches which are dragging water more by virtue of their levels.
Improvements with use of booster pumps, shafts and master pieces
Improvements can be done by adopting booster pumping. It uses the same quantity of water but it is further energized by using pumps. Consumers are satisfied with the increase in pressure.
Boosters can used in the form external source such as borewells or tubewells and direct pumping into the system. External water quantity may be very low compared to distribution flow, but it increases the pressure very effectively.
It is convenient to think of erecting a shaft of appropriate diameter and height in the system for getting a better control of pressures. The shaft can get water either externally or it may get water from the existing ESR through a separate feeder. External supply can be using pumps on the bore well or tube wells.
Conceptually shaft is nothing but an ESR operating with its lowest water level in the outlet pipe and not in the container. Incoming water is equal to outgoing. In the shaft there is central pipe having a small diameter than the outer pipe having a comparatively bigger diameter designed to carry the demand flow of the zone of influence. Both the concentric pipes shall be in mild steel so that the weight of shaft assembly to be erected shall be easy to handle. Shaft can be erected on a good pedestal of masonry or concrete of appropriate height. Annular space between the vertical pipes acts as a container and it can be provided with multioutlets for ensuring zoning. Pressure building characteristics are better in respect of shaft compared to ESR. Shafts are better suited where the zone to be supplied is comparatively at lower ground levels.
When the pressures in the distribution system are low and time duration of supply is also comparatively less low lying areas are benefited more in comparison with the higher level areas. Retained duration of water supply in the system in the lower areas is more as well as the pressures. Consumers in higher areas are aggrieved of getting less supply of water and with lesser pressures. In such cases, select the mains of higher and lower areas. For balancing the heads introduce a smaller diameter metallic pipe having a length of minimum 20 times diameter of main pipe and ensure fixity concentrically by sealing the annular space by cement mortar. This is a trial and error method and within one or two trails exact diameter of small pipe is found out. This piece of pipe is known as ‘master piece’ and it functions most satisfactorily.
UNDERGROUND BANDHARAS
Underground bandharas of various types have been constructed at Yavatmal, Amaravati and Satara districts. Large rivers such as Krishna, Wardha, Painganga , Pus, Bembla, have been crossed successfully by RCC, masonry bandharas. Similarly, nallas small rivers have been crossed by masonry, soil bandharas. Overall total more than 50 bandharas have been constructed using the site conditions. One Arch type bandhara on Arunavati river has been successfully constructed. Everywhere the experience was different. However, every bandhara was useful to the water supply system. While constructing new concepts were added. Confidence level for all the staff was high. Funding was mostly done by the Collectorate from the scarcity funds. Problems tried by construction of bandharas were completely solved and they did not crop up again. In other districts MJP did not contribute in construction of bandharas to a larger extent. But this experience was shared to many people and canvassed for the benefits. A large size river crossing within a very short time of about three weeks is a challenging job. It is a scheduled work and time bound activities are required to be planned. Dewatering problem was not a problem. It was better to plan for diversion than pumping. Hence, it was economical and it is worth noting that none of bandhara was costing more than five lakhs in the years 1992 to 2000. That is why it could be accommodated in the scarcity funds.
Underground bandharas are constructed to arrest the underground water currents and also create a barrier to hold water upstream in the subsurface. It is provided as a conservation measure. They are economical structures. They are not expected to flood the upstream ground surface. They create a potential difference in subsurface water levels. Underground filtration is also expected. Ground water level is also improved. Scarcity may or may not be required; it creates a positive interaction of source improvements.
Combination of underground bandhara and above ground barrier can be done. Both these structures can be in one line or having horizontal distance in between. Above ground structures are built across the natural drain and try to arrest the surface water. It has a chance to percolate water downstream in the subsurface. When the underground water is pumped out of the system from the wells, recharging takes place and water currents are established.
Apart from increase in water quantity in soil, quality is also improved. Further soil movement along with current is restricted.
SOIL BANDHARA
Underground bandharas can be constructed in soil, cement concrete and/or in masonry. In case of soil bandhara, however, excavation across the stream has to be done up to hard strata. Bottom width has to be designed for depth of excavation up to hard strata. This depth is normally found to be 3 to 4 m. Accordingly, base width for soil bandhara comes to minimum 3 to 4 m. Section at the top can be minimum 1 m, which is about 0.3 m below the bed level in natural drain.
For better and stable construction soil filled in plastic bags of cement can be used and constructed in fashion of brick masonry, is recommended. For protection from sides and top two layers of brick on edges shall be provided. Approximate cost of this type of construction works out to Rs. 5000/- per meter length of underground bandhara.
Soil bandhara can be constructed across a nalla or small size river. Time available for construction is about 30 days in the summer, when water level is very low in the natural drain and dewatering involved can be minimum. Similarly, dewatering during construction can be minimized by diverting the flow, rather than pumping out water. Practically, no skilled labour is involved for construction. Local labour can do the job satisfactorily.
Barrier constructed across the natural drain causes resistance to natural full flow of water in the rainy season. Flow carries silt and it will try to accumulate along upstream side of underground bandhara. It will exert pressure on the section of bandhara and this will be maximum at the center. The decided section should withstand the pressures. Further, on downstream side there can be a void, created due to barrier. In this void on rear side a scouring is expected. But after one season the conditions get stabilized. Effects are seen immediately in same season. Water retention upstream becomes effective and becomes useful during summer period.
If the soil bandhara is constructed without packing black cotton soil in plastic bags, then there are chances that soil can get displaced and effects of bandhara are not seen in the consecutive years.
Black cotton soil in wet conditions swells and it exerts pressures on the edges and it tries to come out of the confined position. It is therefore necessary to use plastic empty cement bags for the black cotton soil. Similarly the trapezoidal section of the soil bag masonry has to be retained in shape by providing brick on edge packing in two layers.
MASONRY BANDHARA
In case of masonry bandhara length of bandhara is more important in design. At every 2 m to 3 m distance along length a pier like structure should be provided to break the continuity. Size of pier should be distinctly more than the wall thickness. For a depth of 4 m, masonry thickness should be minimum 2 m at the base and then it can be tapered up to the top. Minimum top width should be 60 cm and should be walk-able. Normally, masonry bandharas are taken to 1 m to 1.5 m above the bed surface. This ensures impounding of some surface water. For occasional draining of water flanged pipe pieces are required to be provided. On the flanged ends sluice valves shall be fitted or blank flanges can be fitted. These can used to remove the accumulated silt near the upstream base of bandhara.
As masonry bandhara is designed to impound water, it will be replenished continuously by the surface flow. If surface flow is in excess of any drawal from the system then water will overflow from the artificial barrier created. Downstream structure has to be designed for the overflow. A small height bucket has to be constructed along the downstream edge so that its energy gets dissipated. This arrangement protects the foundation. Also, it smoothens the downstream flow.
Impounded water percolates underground and recharges the supply wells. This action ensures the availability of water in the summer period. Natural underground water currents are established. Thus by construction of bandhara, localized raising of surface water is ensured and all its advantages are deployed.
When there is a natural ponding in the stream, some impervious barriers exist downstream. Some of rocky outcrops also rise above surface across the stream bed. The geography has to be studied carefully and the advantage can be taken to join these rock outcrops by constructing masonry to create a bandhara just above the existing natural underground bandhara. This is the most economical proposal of constructing masonry bandhara. The joints have to be carefully constructed. For having substantial anchorage in the harder strata, bores can be drilled and steel anchor bars can be provided and grouted with cement mortar.
Constructing masonry and soil bandhara is choice as per the available site conditions. Masonry bandharas are slightly costlier as far as per meter cost is concerned. But these are semi-permanent structures and can be relied upon. When soft rock is available at nearer depths masonry bandhara is appropriate choice and in case of soft strata for deeper depths is available then, soil bandhara is a better choice. Similarly when banks are not sound soil bandhara is a better proposal.
R.C.C. BANDHARA
Wherever masonry is proposed RCC bandhara can be proposed. RCC bandhara becomes economical due to its design. The sections are less as compared to masonry sections. Designed as couterforts, the structures are really sturdy. Fixtures, such as pipes and valves, are easily adoptable. Further construction of downstream water bucket is also easy. As far as economics is concerned per meter cost of RCC is slightly less than that of masonry bandhara. Composite RCC and masonry structures in case of joining of out-crops, can be thought of because they are further economical.
PROTECTION OF BANKS
It has been observed that the floodwater has a tendency to damage the banks. If these banks are of soil, they are likely to be cut by the floodwater. These banks need to be protected. Masonry or RCC bandhara structure has to be taken into the banks for getting sufficient anchorage. Any loose portion of the bank has to be removed. Provide a stone pitching for sufficient area upstream as well as downstream. Very high soil banks shall be avoided. Further, try to provide full overflow section for the bandhara. The top should have a central depression, so that, initially the flow should start from the central portion and as the flow increases it should spread all over the section. During floods all the valves at the bottom shall have to be opened. It will carry silt and large quantity of water, which will flow downstream.
This is the part, which has to be carefully attended to during maintenance. Removal of silt and protection of banks has to be carefully attended to. It will increase the life of bandhara.
EXPECTED STORAGE
When the bandhara top is above the bed surface (1.5m), then some water has to be stored in the nalla/river bed. If the slope of bed is known then the length of stored water can be known e.g.
Assume, 1 = length of bed
b = width of bed
h = height of bandhara, then,
storage = 0.5*b*i*h
Assume, b = 150 m, 1 = 1500 m, and h = 1.5 m, then,
Storage = 0.5*150*1500*1.5 = 168750 cum = 168.75 ML
There are number of other factors which affect the storage quantity. Cross-section of bed width, depression in the bed and outcrops in the, bed strata, etc., has influence on the possible stored quantity.
Thus, when bandhara is full and overflowing assume about 150 ML of water is stored. When overflow stops depletion starts. Depletion may be due to pumping, evaporation and by seepage. Still, the available water can be used for pumping the storage builds up confidence in the maintenance of water supply system.
For urban water supply scheme this storage can be calculated in terms of days of city water supply. For population of 50000 souls, at the rate of 70 lpcd, daily demand is 3.5 ML. Storage in the above example will be adequate for 45 days minimum.
When bandhara is full, the surface area is 1500*150 = 225000 sq. m, and storage acts as large settling tank. Instead of increasing the height of bandhara, in the natural drain, it is always better to construct a small bandhara upstream beyond the possible maximum spread of the existing bandhara. Such series of storages upstream, will be giving natural background to the river course. If the water is flowing in the river, then it will create series of storages in the bed. In case of letting out water in the river course through a dam, then also water utilization through bandharas downstream is justified.
Some of the water is utilized for agricultural irrigation purposes. These are the system losses. However, the green area development is an asset. Water stored has multiple uses and benefits. These benefits are interactive. All concerned indirectly contribute to continue the flowing conditions of natural stream. In short, the environment is changed by construction of bandhara.
Underground bandharas of various types have been constructed at Yavatmal, Amaravati and Satara districts. Large rivers such as Krishna, Wardha, Painganga , Pus, Bembla, have been crossed successfully by RCC, masonry bandharas. Similarly, nallas small rivers have been crossed by masonry, soil bandharas. Overall total more than 50 bandharas have been constructed using the site conditions. One Arch type bandhara on Arunavati river has been successfully constructed. Everywhere the experience was different. However, every bandhara was useful to the water supply system. While constructing new concepts were added. Confidence level for all the staff was high. Funding was mostly done by the Collectorate from the scarcity funds. Problems tried by construction of bandharas were completely solved and they did not crop up again. In other districts MJP did not contribute in construction of bandharas to a larger extent. But this experience was shared to many people and canvassed for the benefits. A large size river crossing within a very short time of about three weeks is a challenging job. It is a scheduled work and time bound activities are required to be planned. Dewatering problem was not a problem. It was better to plan for diversion than pumping. Hence, it was economical and it is worth noting that none of bandhara was costing more than five lakhs in the years 1992 to 2000. That is why it could be accommodated in the scarcity funds.
Underground bandharas are constructed to arrest the underground water currents and also create a barrier to hold water upstream in the subsurface. It is provided as a conservation measure. They are economical structures. They are not expected to flood the upstream ground surface. They create a potential difference in subsurface water levels. Underground filtration is also expected. Ground water level is also improved. Scarcity may or may not be required; it creates a positive interaction of source improvements.
Combination of underground bandhara and above ground barrier can be done. Both these structures can be in one line or having horizontal distance in between. Above ground structures are built across the natural drain and try to arrest the surface water. It has a chance to percolate water downstream in the subsurface. When the underground water is pumped out of the system from the wells, recharging takes place and water currents are established.
Apart from increase in water quantity in soil, quality is also improved. Further soil movement along with current is restricted.
SOIL BANDHARA
Underground bandharas can be constructed in soil, cement concrete and/or in masonry. In case of soil bandhara, however, excavation across the stream has to be done up to hard strata. Bottom width has to be designed for depth of excavation up to hard strata. This depth is normally found to be 3 to 4 m. Accordingly, base width for soil bandhara comes to minimum 3 to 4 m. Section at the top can be minimum 1 m, which is about 0.3 m below the bed level in natural drain.
For better and stable construction soil filled in plastic bags of cement can be used and constructed in fashion of brick masonry, is recommended. For protection from sides and top two layers of brick on edges shall be provided. Approximate cost of this type of construction works out to Rs. 5000/- per meter length of underground bandhara.
Soil bandhara can be constructed across a nalla or small size river. Time available for construction is about 30 days in the summer, when water level is very low in the natural drain and dewatering involved can be minimum. Similarly, dewatering during construction can be minimized by diverting the flow, rather than pumping out water. Practically, no skilled labour is involved for construction. Local labour can do the job satisfactorily.
Barrier constructed across the natural drain causes resistance to natural full flow of water in the rainy season. Flow carries silt and it will try to accumulate along upstream side of underground bandhara. It will exert pressure on the section of bandhara and this will be maximum at the center. The decided section should withstand the pressures. Further, on downstream side there can be a void, created due to barrier. In this void on rear side a scouring is expected. But after one season the conditions get stabilized. Effects are seen immediately in same season. Water retention upstream becomes effective and becomes useful during summer period.
If the soil bandhara is constructed without packing black cotton soil in plastic bags, then there are chances that soil can get displaced and effects of bandhara are not seen in the consecutive years.
Black cotton soil in wet conditions swells and it exerts pressures on the edges and it tries to come out of the confined position. It is therefore necessary to use plastic empty cement bags for the black cotton soil. Similarly the trapezoidal section of the soil bag masonry has to be retained in shape by providing brick on edge packing in two layers.
MASONRY BANDHARA
In case of masonry bandhara length of bandhara is more important in design. At every 2 m to 3 m distance along length a pier like structure should be provided to break the continuity. Size of pier should be distinctly more than the wall thickness. For a depth of 4 m, masonry thickness should be minimum 2 m at the base and then it can be tapered up to the top. Minimum top width should be 60 cm and should be walk-able. Normally, masonry bandharas are taken to 1 m to 1.5 m above the bed surface. This ensures impounding of some surface water. For occasional draining of water flanged pipe pieces are required to be provided. On the flanged ends sluice valves shall be fitted or blank flanges can be fitted. These can used to remove the accumulated silt near the upstream base of bandhara.
As masonry bandhara is designed to impound water, it will be replenished continuously by the surface flow. If surface flow is in excess of any drawal from the system then water will overflow from the artificial barrier created. Downstream structure has to be designed for the overflow. A small height bucket has to be constructed along the downstream edge so that its energy gets dissipated. This arrangement protects the foundation. Also, it smoothens the downstream flow.
Impounded water percolates underground and recharges the supply wells. This action ensures the availability of water in the summer period. Natural underground water currents are established. Thus by construction of bandhara, localized raising of surface water is ensured and all its advantages are deployed.
When there is a natural ponding in the stream, some impervious barriers exist downstream. Some of rocky outcrops also rise above surface across the stream bed. The geography has to be studied carefully and the advantage can be taken to join these rock outcrops by constructing masonry to create a bandhara just above the existing natural underground bandhara. This is the most economical proposal of constructing masonry bandhara. The joints have to be carefully constructed. For having substantial anchorage in the harder strata, bores can be drilled and steel anchor bars can be provided and grouted with cement mortar.
Constructing masonry and soil bandhara is choice as per the available site conditions. Masonry bandharas are slightly costlier as far as per meter cost is concerned. But these are semi-permanent structures and can be relied upon. When soft rock is available at nearer depths masonry bandhara is appropriate choice and in case of soft strata for deeper depths is available then, soil bandhara is a better choice. Similarly when banks are not sound soil bandhara is a better proposal.
R.C.C. BANDHARA
Wherever masonry is proposed RCC bandhara can be proposed. RCC bandhara becomes economical due to its design. The sections are less as compared to masonry sections. Designed as couterforts, the structures are really sturdy. Fixtures, such as pipes and valves, are easily adoptable. Further construction of downstream water bucket is also easy. As far as economics is concerned per meter cost of RCC is slightly less than that of masonry bandhara. Composite RCC and masonry structures in case of joining of out-crops, can be thought of because they are further economical.
PROTECTION OF BANKS
It has been observed that the floodwater has a tendency to damage the banks. If these banks are of soil, they are likely to be cut by the floodwater. These banks need to be protected. Masonry or RCC bandhara structure has to be taken into the banks for getting sufficient anchorage. Any loose portion of the bank has to be removed. Provide a stone pitching for sufficient area upstream as well as downstream. Very high soil banks shall be avoided. Further, try to provide full overflow section for the bandhara. The top should have a central depression, so that, initially the flow should start from the central portion and as the flow increases it should spread all over the section. During floods all the valves at the bottom shall have to be opened. It will carry silt and large quantity of water, which will flow downstream.
This is the part, which has to be carefully attended to during maintenance. Removal of silt and protection of banks has to be carefully attended to. It will increase the life of bandhara.
EXPECTED STORAGE
When the bandhara top is above the bed surface (1.5m), then some water has to be stored in the nalla/river bed. If the slope of bed is known then the length of stored water can be known e.g.
Assume, 1 = length of bed
b = width of bed
h = height of bandhara, then,
storage = 0.5*b*i*h
Assume, b = 150 m, 1 = 1500 m, and h = 1.5 m, then,
Storage = 0.5*150*1500*1.5 = 168750 cum = 168.75 ML
There are number of other factors which affect the storage quantity. Cross-section of bed width, depression in the bed and outcrops in the, bed strata, etc., has influence on the possible stored quantity.
Thus, when bandhara is full and overflowing assume about 150 ML of water is stored. When overflow stops depletion starts. Depletion may be due to pumping, evaporation and by seepage. Still, the available water can be used for pumping the storage builds up confidence in the maintenance of water supply system.
For urban water supply scheme this storage can be calculated in terms of days of city water supply. For population of 50000 souls, at the rate of 70 lpcd, daily demand is 3.5 ML. Storage in the above example will be adequate for 45 days minimum.
When bandhara is full, the surface area is 1500*150 = 225000 sq. m, and storage acts as large settling tank. Instead of increasing the height of bandhara, in the natural drain, it is always better to construct a small bandhara upstream beyond the possible maximum spread of the existing bandhara. Such series of storages upstream, will be giving natural background to the river course. If the water is flowing in the river, then it will create series of storages in the bed. In case of letting out water in the river course through a dam, then also water utilization through bandharas downstream is justified.
Some of the water is utilized for agricultural irrigation purposes. These are the system losses. However, the green area development is an asset. Water stored has multiple uses and benefits. These benefits are interactive. All concerned indirectly contribute to continue the flowing conditions of natural stream. In short, the environment is changed by construction of bandhara.
Saturday, February 23, 2008
OPTIMISATION OF TREATMENT PLANT UNITS
OPTIMISATION OF TREATMENT PLANT UNITS
Treatment plant is an important sub work in the total system of the water supply facility. Normally plant cost does not exceed 4 to 5 % of the whole system. Conveyance system is designed for 30 years. Pumping machinery and treatment plant is designed for 15 years. Pump capacity reduces to about 12 % till the end of the design period. Hence, initially the design capacity is increased by 12 % for raw water as per MJP practices. Further hours of pumping are restricted to 20 hours at the end of design period. Hence, pumping rates are increased by 20%. With all this parameters rated plant capacity is increased. As other components are designed for 30 years the location of second stage treatment facility is practically decided. Modifications in treatment plant capacity to slightly on higher side does not increase the system cost much but it ensures continued treatment after decision is taken to increase the rate of pumping or adding new source. Upgrading treatment facility is normally found to be delayed. It is routed through various procedural formalities and sanctions from authorities. Quantity problem has an upper hand on the quality requirements. Hence, it is always better to have safe margins for the treatment facility and it can be stretched to optimization of the existing utility. At Yavatmal pumping was doubled and existing plant was tuned or rest to the new flow conditions locally and it was in use for about 5 years till the new plant was constructed. New unconventional treatment plants constructed Pandharkawada and other 6 places has an intrinsic capacity to deal with double flow with very minor modifications. Such aspects are introduced in the designs keeping the system maintenance orientation. Amaravati system of augmentation had the sanctioned capacity of treatment plant as 69 MLD, however, using different factors actual construction was 95 MLD. It is to mention that construction cost accepted was within the sanctioned provisions.
1. INTRODUCTION
1.1 Plant capacity is measured on the basis of the flow of water through treatment units per hour. It can be represented by flow per day, by converting flow per hour to flow per day. Some units of the plant are designed for even double the flow but in general all the units are designed for 20% over loading. Normally there is an apprehension that the filters are required to design for 20 % overloading. This is practically not correct. If flow is increased all units are hydraulically loaded. Filters are more loaded during sequential washing of beds. With the increase in loading there are no physical cost incidence, except relevant to cost on MLD basis. Plant capacity in other terms can be treated as the hydraulic capacity. Though on way the water is purified while flowing through the plant, the incoming water quality is a subsidiary parameter to decide the water treatment plant capacity.
1.2 Water enters the Treatment Plant at higher level and leaves the plant at lower level. The difference of the level is normally of the order of 6 m. to 8 m. Hydraulics of each unit is different, but water looses its head through the treatment plant and gets purified.
2. PRESENT DESIGN PRACTICES FOR PRE-SEDIMENTATION UNITS
2.1 The design of each unit is based upon the hydraulics of water flowing through that unit. It may be associated with other parameters related to the physical and chemical impurities in the water. Aeration fountain and measuring channel both have no moving parts. They can be designed for higher flow and hence it is a practice to provide these two units for the maximum flow or double the design flow.
2.2 Flash mixer is designed for the detention period of 1 min. and if this unit is operated for double the flow, then the detention period is reduced. Still, the size of this unit is comparatively very small and hence civil construction cost is less. Initially this unit may be constructed for double the flow. Otherwise flow through this unit may be diverted through distribution chamber so that flow run time is increased and the same unit can be used for more than the designed flow. Regarding the mechanical equipment of flash mixing the motor H.P. ranges from 5 H.P. to 8 H.P. and hence, providing some more initial H.P. will take care of the increased flow that it may be required to handle. Care should be taken to isolate the F.S.L. in the flash mixer by distinct level difference from measuring channel sill. However, this is dependent on the down take flow from flash mixer to flocculater. This pipe line should be capable of taking maximum possible flow or its hydraulics should be decided by designing the line for double the flow. Further as these lines are to be laid beneath the Clariflocculator regular standby line should be provided. Initially, valve controls shall have to be operated but this arrangement can take care of double the flow and economics is not affected much. Initial construction of tapered flocculation has better overloading capacity.
3. IMPORTANT ASPECTS OF DESIGN OF CLARIFLOCCULATOR UNITS:-
3.1 Intake column in the flocculator is important component for design. The main aspect is that the velocity flowing upwards should be such that there should be no settlement, and hence the diameter should be minimum. If the same column is used for double the flow upward velocity is increased. Hence, this column should be designed in such a way that in case of design flow the velocity should be such that the particles should not settle and in case of double the flow the velocity in the column should not be more than 1.8m/Sec. Hence, the velocity range should be 0.8m/Sec. to 1.8m/Sec. during design flow and double the design flow. It is economical to consider the size of intake column of the optimum diameter; considering the possibility of overloading.
3.2 Flocculator detention time should be considered as 30 min. of flow/hr. Design flow may be1.2 times the normal flow. If the depth and diameter is designed according to this design flow, the flocculator capacity can be calculated. Detention time and side water depth are the only parameters in design of flocculator unit. When double the flow is passed through this unit, detention time is reduced. Hence, initially slightly more detention time may be provided. Civil construction cost will not be increased disproportionately. By the application of accurate dosing of chemicals, the floc formation can be satisfactorily achieved. Flocculator mechanism shall be provided with sufficient paddles, so that the slow mixing by paddles can be effectively achieved. Dorr-oliver type mechanism gives more satisfactory results. Using the same units and by changing the speed of rotation slightly, required ‘G’ valve can be achieved while operating on double the flow conditions. The question of optimization of ‘GT’ valve parameter can be solved by increasing slightly the initial detention time of flocculator.
3.3 Clarifier is the most important unit as far as handling double the normal flow is concerned. Clarifier area is calculated on the basis of assumed over flow rate. Approximately, 1.5m/hr. is commonly used overflow rate. This overflow rate is for assumed design particle which should settle in that clarifier within given detention time. It means that, if the flow is doubled, than design particle should not settle in the tank and it will be carried away in the further units. However, this is further depended upon the weir flow rate. If the weir flow rate is as small as possible say 200 cum/m/day; then the tendency of the design particle being carried away in the further units is slightly curbed.
3.4 In view of the future planning, hence, the clarifier is most important unit to be carefully designed. Even by rearranging the capacity or detention time of the clarifier and restricting the side water depth, the area of the clarifier can be increased. Without increasing the civil construction cost much more. If initially larger diameter clarifier is provided then it is possible to use the same clarifier for double the flow. For bigger plants, optimum capacity of CLF shall be 30 MLD. Increasing number of units is more reasonable than to have option of larger size units.
3.5 Though theoretically, the overflow rate indicates the design velocity of the particle to settle in the clarifier. Particle settling velocity will be decedent on the temperature and other climatic conditions.
3.6 Designing for the higher flow will increase the diameter of this unit, but it must be pointed out that most of the designers are inclined to reduce the diameter to save in construction cost and still they may try to satisfy the conditions of overflow rate as well as far the detention time. Increasing the depth and restricting the diameter will give the same detention time but for clarifier depth is not important and the diameter is important as far as the overflow rate is concerned. Further, the increased diameter will also provide for the increased weir length. Even a two edged peripheral weir will not cost much but the commercial designers do not adopt to it for saving the initial cost. This tendency should be specifically curbed by providing specific conditions in the tender.
3.7 In the design of clariflocculator, Turbidity of incoming water is not a parameter. It only deals with the average size of the particle of turbidity which should settle in the clarifier. Turbidity of incoming water has large variations. In the rainy days, it may be up to 4000 ppm and in other days it may be reduced to 150 ppm. Theoretically, sedimentation should remove all the turbidity, but working design permits outlet turbidity from clariflocculator as 15 ppm. In terms of efficiency in rainy season this unit has the removal efficiency 4000 – 15 = 3985 = 99.62%
4000 4000
Whereas in other days the turbidity removal efficiency may be of the order of
150 – 15 = 135 = 90%
150 150
The increase in efficiency in rainy season is normally attributed to Alum dosing and floc formation. With the increase in hydraulic loading, Turbidity to be handled is also increased. It will require higher Alum dosing and more effective flocculation by adjusting ‘G” valve. If the same diameter floc is formed, theoretically it should not settle in the clarifier as design overflow rate will not permit to do so.
Actual overflow rate is much more; and hence upward velocity is much more and theoretically all the flocs should be washed away to the further units.
3.8 Overflow rate is related to the size of floc. In the flocculation zone it is assumed that the floc formation shall be of same size. But floc formation will depend upon the incoming turbidity and the Alum dosing, effective mixing of Alum dose, and impurities in the Alum. It will also depend upon the entry of water in the flocculation tank and velocity of entry of the water. Size of floc will also depend upon the effective paddle area and paddle speed. Even with the control of all such parameters it can be found that size of floc does not remain constant. Hence, the floc sizes will have a gradation. The floc, size of which is higher than the particle size for which overflow rate is decided, will settle in the clarifier.
3.9 The particle size which is not designed to settle in the tank, with the same overflow rate will try to rise in the tank. It is possible that its position in the tank be balanced up to the weir level. In that case also the particle will not be carried away. Hence, the overflow rate of 1.5 m /hr. will not indicate that particular size of particle will settle only, but it may also indicate that some lighter particles will take more time to settle but will remain in suspension. It is observed at Yavatmal Treatment Plant, that even after doubling the flow, the outlet turbidity was possible to be controlled within 20 ppm range. Such overloading of the plant is going on at Amravati Treatment Plant and it is experienced that outlet turbidity can be controlled in the same clariflocculator.
3.10 Controlling the weir flow rate and maintaining the clear overfall conditions in the launder is most important consideration. Hydraulically, the channels should be capable of accommodating higher flows and it is very important, as it will not overload the units. Economics is not disturbed by providing wider channels. Only thing that, it is required to foresee the position, some years ahead when flow is required to be increased. Instead of going for separate treatment unit, it is required to exploit the provisions existing. However, such exploitation can be anticipated and at least hydraulics in that stage can be imagined and provided for, at the present stage without disturbing the economics.
3.11 Standard design of Treatment Plant was published in the Indian Water Works Journals. It provides for a detention time of clairflocculator as 3 hours, standing water depth as 3.5m. and additional sludge storage capacity of 25% of detention time. Similarly flocculator detention time is taken as 30 minutes as normal.
3.12 However, the commercial designs try to economics in the diameter of clarifier by increasing the S.W.D suitably for the design conditions of flow. The clariflocculator does work, but its utilization for the higher flow becomes limited. Hence, it is to point out that the real economics does not apply to the utilization in the present stage, but it is advantageous to continue utilization in the future stage. If this concept is acceptable the hydraulic design of various channels and piping for the higher flow (suitably double the flow) needs no justification.
4. FLEXIBILITY OF OPERATION IN FILTERATION UNITS:
4.1 The filters are designed for filtration rate of 5000 lit/sq.m./hr. This hydraulic loading will take care of incoming turbidity of 20 ppm. and the filtrate will be available having turbidity below 1 ppm. The flexibility in operation of filters, is due to following reasons,
a) The nature of sand can be suitably decided. The parameters, uniformity coefficient and effective size for the sand can be varied to suit the rate of filtration. The sand parameters can be changed even during the course of maintenance.
b) The period of backwashing can be adjusted so that the filters are prevented from choking and cracking. After a certain predefined loss of head through filters, the backwashing can be done and the filters are again ready to receive a fresh load. Normally filters are designed for 20% hydraulic overloading. During backwashing of one of the units, others are overloaded hydraulically.
c) Filtrate quality, if not attended to properly, gets disturbed, say up to 2 to 4 ppm from the normal expected quality below 1 ppm. This change however, is not noticeable. Hence, the delay in attending to properly, though not justified, remains in tolerance limits.
4.2 Backwash water is wastage. as far as the treatment plant is concerned. Parameters indicating minimum wastage of water are available. Normal wastage is 2%, based on annual average flow through treatment plant. With design loadings, the filter beds are not choked within 24 hours filter runs. If the loading is increased the backwashing becomes necessary, earlier. The wastage of backwash water is then increased in that preparation. If such wastage is arranged to be re-circulated, the parameter relating to wastage due to backwash water; is taken care of.
5. ADVANTAGES OF RECIRCULATION OF BACKWASH WATER
5.1 Recirculation of backwash water reduces the final wastage of water. It adds to the turbidity of incoming water. It improves flocculent settling. If the clarifier wastage is also re-circulated then it adds, thicker turbidity in the incoming water and settling characteristics are improved. Alum is also partially re-circulated hence dose of Alum required is reduced.
5.2 On comparison it can be revealed that recirculation of waste water is finally cheaper.
6. CONCLUSIONS;
6.1 In most of the Urban Water Supply Schemes design demands for the scheme as a whole do not match with the actual demands of the city due to fast urbanization. The augmentation stage comes earlier than anticipated. Hence, the city remains in difficulties as far as water supply is concerned. It is due to this reason the designer should plan for the next stage also. The treatment units should not be designed only for the present stage; but they should be designed for higher stage. Economics should not be considered for the initial stage but considering its use in the later stage.
6.2 In case of existing treatment facilities overloading should be tried preferentially though in some cases the plants are overloaded in the pre-augmentation stage. Necessary changes can be thought of in the various units. If it is obligatory to add facility, only sedimentation facility should be tried to be added in the first instance.
6.3 In all the cases, channels, overflows, by passes and other pipelines should invariably and economically designed and provided to carry double the design flow. Economy in restricting the total head loss through treatment plant should better be avoided.
6.4 A second thought before construction of a new treatment plant will be helpful considering the optimum utilization of existing facility.
Treatment plant is an important sub work in the total system of the water supply facility. Normally plant cost does not exceed 4 to 5 % of the whole system. Conveyance system is designed for 30 years. Pumping machinery and treatment plant is designed for 15 years. Pump capacity reduces to about 12 % till the end of the design period. Hence, initially the design capacity is increased by 12 % for raw water as per MJP practices. Further hours of pumping are restricted to 20 hours at the end of design period. Hence, pumping rates are increased by 20%. With all this parameters rated plant capacity is increased. As other components are designed for 30 years the location of second stage treatment facility is practically decided. Modifications in treatment plant capacity to slightly on higher side does not increase the system cost much but it ensures continued treatment after decision is taken to increase the rate of pumping or adding new source. Upgrading treatment facility is normally found to be delayed. It is routed through various procedural formalities and sanctions from authorities. Quantity problem has an upper hand on the quality requirements. Hence, it is always better to have safe margins for the treatment facility and it can be stretched to optimization of the existing utility. At Yavatmal pumping was doubled and existing plant was tuned or rest to the new flow conditions locally and it was in use for about 5 years till the new plant was constructed. New unconventional treatment plants constructed Pandharkawada and other 6 places has an intrinsic capacity to deal with double flow with very minor modifications. Such aspects are introduced in the designs keeping the system maintenance orientation. Amaravati system of augmentation had the sanctioned capacity of treatment plant as 69 MLD, however, using different factors actual construction was 95 MLD. It is to mention that construction cost accepted was within the sanctioned provisions.
1. INTRODUCTION
1.1 Plant capacity is measured on the basis of the flow of water through treatment units per hour. It can be represented by flow per day, by converting flow per hour to flow per day. Some units of the plant are designed for even double the flow but in general all the units are designed for 20% over loading. Normally there is an apprehension that the filters are required to design for 20 % overloading. This is practically not correct. If flow is increased all units are hydraulically loaded. Filters are more loaded during sequential washing of beds. With the increase in loading there are no physical cost incidence, except relevant to cost on MLD basis. Plant capacity in other terms can be treated as the hydraulic capacity. Though on way the water is purified while flowing through the plant, the incoming water quality is a subsidiary parameter to decide the water treatment plant capacity.
1.2 Water enters the Treatment Plant at higher level and leaves the plant at lower level. The difference of the level is normally of the order of 6 m. to 8 m. Hydraulics of each unit is different, but water looses its head through the treatment plant and gets purified.
2. PRESENT DESIGN PRACTICES FOR PRE-SEDIMENTATION UNITS
2.1 The design of each unit is based upon the hydraulics of water flowing through that unit. It may be associated with other parameters related to the physical and chemical impurities in the water. Aeration fountain and measuring channel both have no moving parts. They can be designed for higher flow and hence it is a practice to provide these two units for the maximum flow or double the design flow.
2.2 Flash mixer is designed for the detention period of 1 min. and if this unit is operated for double the flow, then the detention period is reduced. Still, the size of this unit is comparatively very small and hence civil construction cost is less. Initially this unit may be constructed for double the flow. Otherwise flow through this unit may be diverted through distribution chamber so that flow run time is increased and the same unit can be used for more than the designed flow. Regarding the mechanical equipment of flash mixing the motor H.P. ranges from 5 H.P. to 8 H.P. and hence, providing some more initial H.P. will take care of the increased flow that it may be required to handle. Care should be taken to isolate the F.S.L. in the flash mixer by distinct level difference from measuring channel sill. However, this is dependent on the down take flow from flash mixer to flocculater. This pipe line should be capable of taking maximum possible flow or its hydraulics should be decided by designing the line for double the flow. Further as these lines are to be laid beneath the Clariflocculator regular standby line should be provided. Initially, valve controls shall have to be operated but this arrangement can take care of double the flow and economics is not affected much. Initial construction of tapered flocculation has better overloading capacity.
3. IMPORTANT ASPECTS OF DESIGN OF CLARIFLOCCULATOR UNITS:-
3.1 Intake column in the flocculator is important component for design. The main aspect is that the velocity flowing upwards should be such that there should be no settlement, and hence the diameter should be minimum. If the same column is used for double the flow upward velocity is increased. Hence, this column should be designed in such a way that in case of design flow the velocity should be such that the particles should not settle and in case of double the flow the velocity in the column should not be more than 1.8m/Sec. Hence, the velocity range should be 0.8m/Sec. to 1.8m/Sec. during design flow and double the design flow. It is economical to consider the size of intake column of the optimum diameter; considering the possibility of overloading.
3.2 Flocculator detention time should be considered as 30 min. of flow/hr. Design flow may be1.2 times the normal flow. If the depth and diameter is designed according to this design flow, the flocculator capacity can be calculated. Detention time and side water depth are the only parameters in design of flocculator unit. When double the flow is passed through this unit, detention time is reduced. Hence, initially slightly more detention time may be provided. Civil construction cost will not be increased disproportionately. By the application of accurate dosing of chemicals, the floc formation can be satisfactorily achieved. Flocculator mechanism shall be provided with sufficient paddles, so that the slow mixing by paddles can be effectively achieved. Dorr-oliver type mechanism gives more satisfactory results. Using the same units and by changing the speed of rotation slightly, required ‘G’ valve can be achieved while operating on double the flow conditions. The question of optimization of ‘GT’ valve parameter can be solved by increasing slightly the initial detention time of flocculator.
3.3 Clarifier is the most important unit as far as handling double the normal flow is concerned. Clarifier area is calculated on the basis of assumed over flow rate. Approximately, 1.5m/hr. is commonly used overflow rate. This overflow rate is for assumed design particle which should settle in that clarifier within given detention time. It means that, if the flow is doubled, than design particle should not settle in the tank and it will be carried away in the further units. However, this is further depended upon the weir flow rate. If the weir flow rate is as small as possible say 200 cum/m/day; then the tendency of the design particle being carried away in the further units is slightly curbed.
3.4 In view of the future planning, hence, the clarifier is most important unit to be carefully designed. Even by rearranging the capacity or detention time of the clarifier and restricting the side water depth, the area of the clarifier can be increased. Without increasing the civil construction cost much more. If initially larger diameter clarifier is provided then it is possible to use the same clarifier for double the flow. For bigger plants, optimum capacity of CLF shall be 30 MLD. Increasing number of units is more reasonable than to have option of larger size units.
3.5 Though theoretically, the overflow rate indicates the design velocity of the particle to settle in the clarifier. Particle settling velocity will be decedent on the temperature and other climatic conditions.
3.6 Designing for the higher flow will increase the diameter of this unit, but it must be pointed out that most of the designers are inclined to reduce the diameter to save in construction cost and still they may try to satisfy the conditions of overflow rate as well as far the detention time. Increasing the depth and restricting the diameter will give the same detention time but for clarifier depth is not important and the diameter is important as far as the overflow rate is concerned. Further, the increased diameter will also provide for the increased weir length. Even a two edged peripheral weir will not cost much but the commercial designers do not adopt to it for saving the initial cost. This tendency should be specifically curbed by providing specific conditions in the tender.
3.7 In the design of clariflocculator, Turbidity of incoming water is not a parameter. It only deals with the average size of the particle of turbidity which should settle in the clarifier. Turbidity of incoming water has large variations. In the rainy days, it may be up to 4000 ppm and in other days it may be reduced to 150 ppm. Theoretically, sedimentation should remove all the turbidity, but working design permits outlet turbidity from clariflocculator as 15 ppm. In terms of efficiency in rainy season this unit has the removal efficiency 4000 – 15 = 3985 = 99.62%
4000 4000
Whereas in other days the turbidity removal efficiency may be of the order of
150 – 15 = 135 = 90%
150 150
The increase in efficiency in rainy season is normally attributed to Alum dosing and floc formation. With the increase in hydraulic loading, Turbidity to be handled is also increased. It will require higher Alum dosing and more effective flocculation by adjusting ‘G” valve. If the same diameter floc is formed, theoretically it should not settle in the clarifier as design overflow rate will not permit to do so.
Actual overflow rate is much more; and hence upward velocity is much more and theoretically all the flocs should be washed away to the further units.
3.8 Overflow rate is related to the size of floc. In the flocculation zone it is assumed that the floc formation shall be of same size. But floc formation will depend upon the incoming turbidity and the Alum dosing, effective mixing of Alum dose, and impurities in the Alum. It will also depend upon the entry of water in the flocculation tank and velocity of entry of the water. Size of floc will also depend upon the effective paddle area and paddle speed. Even with the control of all such parameters it can be found that size of floc does not remain constant. Hence, the floc sizes will have a gradation. The floc, size of which is higher than the particle size for which overflow rate is decided, will settle in the clarifier.
3.9 The particle size which is not designed to settle in the tank, with the same overflow rate will try to rise in the tank. It is possible that its position in the tank be balanced up to the weir level. In that case also the particle will not be carried away. Hence, the overflow rate of 1.5 m /hr. will not indicate that particular size of particle will settle only, but it may also indicate that some lighter particles will take more time to settle but will remain in suspension. It is observed at Yavatmal Treatment Plant, that even after doubling the flow, the outlet turbidity was possible to be controlled within 20 ppm range. Such overloading of the plant is going on at Amravati Treatment Plant and it is experienced that outlet turbidity can be controlled in the same clariflocculator.
3.10 Controlling the weir flow rate and maintaining the clear overfall conditions in the launder is most important consideration. Hydraulically, the channels should be capable of accommodating higher flows and it is very important, as it will not overload the units. Economics is not disturbed by providing wider channels. Only thing that, it is required to foresee the position, some years ahead when flow is required to be increased. Instead of going for separate treatment unit, it is required to exploit the provisions existing. However, such exploitation can be anticipated and at least hydraulics in that stage can be imagined and provided for, at the present stage without disturbing the economics.
3.11 Standard design of Treatment Plant was published in the Indian Water Works Journals. It provides for a detention time of clairflocculator as 3 hours, standing water depth as 3.5m. and additional sludge storage capacity of 25% of detention time. Similarly flocculator detention time is taken as 30 minutes as normal.
3.12 However, the commercial designs try to economics in the diameter of clarifier by increasing the S.W.D suitably for the design conditions of flow. The clariflocculator does work, but its utilization for the higher flow becomes limited. Hence, it is to point out that the real economics does not apply to the utilization in the present stage, but it is advantageous to continue utilization in the future stage. If this concept is acceptable the hydraulic design of various channels and piping for the higher flow (suitably double the flow) needs no justification.
4. FLEXIBILITY OF OPERATION IN FILTERATION UNITS:
4.1 The filters are designed for filtration rate of 5000 lit/sq.m./hr. This hydraulic loading will take care of incoming turbidity of 20 ppm. and the filtrate will be available having turbidity below 1 ppm. The flexibility in operation of filters, is due to following reasons,
a) The nature of sand can be suitably decided. The parameters, uniformity coefficient and effective size for the sand can be varied to suit the rate of filtration. The sand parameters can be changed even during the course of maintenance.
b) The period of backwashing can be adjusted so that the filters are prevented from choking and cracking. After a certain predefined loss of head through filters, the backwashing can be done and the filters are again ready to receive a fresh load. Normally filters are designed for 20% hydraulic overloading. During backwashing of one of the units, others are overloaded hydraulically.
c) Filtrate quality, if not attended to properly, gets disturbed, say up to 2 to 4 ppm from the normal expected quality below 1 ppm. This change however, is not noticeable. Hence, the delay in attending to properly, though not justified, remains in tolerance limits.
4.2 Backwash water is wastage. as far as the treatment plant is concerned. Parameters indicating minimum wastage of water are available. Normal wastage is 2%, based on annual average flow through treatment plant. With design loadings, the filter beds are not choked within 24 hours filter runs. If the loading is increased the backwashing becomes necessary, earlier. The wastage of backwash water is then increased in that preparation. If such wastage is arranged to be re-circulated, the parameter relating to wastage due to backwash water; is taken care of.
5. ADVANTAGES OF RECIRCULATION OF BACKWASH WATER
5.1 Recirculation of backwash water reduces the final wastage of water. It adds to the turbidity of incoming water. It improves flocculent settling. If the clarifier wastage is also re-circulated then it adds, thicker turbidity in the incoming water and settling characteristics are improved. Alum is also partially re-circulated hence dose of Alum required is reduced.
5.2 On comparison it can be revealed that recirculation of waste water is finally cheaper.
6. CONCLUSIONS;
6.1 In most of the Urban Water Supply Schemes design demands for the scheme as a whole do not match with the actual demands of the city due to fast urbanization. The augmentation stage comes earlier than anticipated. Hence, the city remains in difficulties as far as water supply is concerned. It is due to this reason the designer should plan for the next stage also. The treatment units should not be designed only for the present stage; but they should be designed for higher stage. Economics should not be considered for the initial stage but considering its use in the later stage.
6.2 In case of existing treatment facilities overloading should be tried preferentially though in some cases the plants are overloaded in the pre-augmentation stage. Necessary changes can be thought of in the various units. If it is obligatory to add facility, only sedimentation facility should be tried to be added in the first instance.
6.3 In all the cases, channels, overflows, by passes and other pipelines should invariably and economically designed and provided to carry double the design flow. Economy in restricting the total head loss through treatment plant should better be avoided.
6.4 A second thought before construction of a new treatment plant will be helpful considering the optimum utilization of existing facility.
RECIRCULATOIN OF WASH WATER
During the daily operations of treatment plant washing of filters is a regular activity. For washing of filters pure water is used and normally it is wasted. In case of higher capacity treatment plants the quantity of wash water wasted is substantial 3% to 5% of the capacity of treatment plant is estimated as waste.
Wash water quantity waste can be minimized by recirculating the waste water by creating an appropriate storage. In case of new treatment plants recirculation can be one of the regular unit and can be simultaneously constructed. However, in case of old treatment plant recirculation feature can be added during maintenance.
Sample calculations are given as below so as to arrive at the economics.
RATE OF FILTRATION 5M3/M2/HR
BED AREA 100M2
MAXIMUM FLOW 12000M3 /DAY
RATE OF BACKWASH 600LIT/M2/MIN
FOR 10 MIN BACKWASH FLOW 600*10*100LIT/DAY 600 M3/DAY
% FLOW OF BACKWASH 5%
ASSUME 80% BACKWASH FOR RECIRCULATION 4% 480 M3/DAY
COST OF RECIRCULATION WATER @ RS. 7.30/M3 480*7.30 = 3504 RS/DAY
REVENUE FROM RECIRCULATION WATER / YEAR 1278960 RS/YEAR
% RECVERY @ 80% OF ABOVE 1023168 RS/YEAR
MINIMUM STORAGE OF RECIRCULATED WATER 480 M3
RATE OF PUMPING 480/24 M3/HR 20 M3/HR
HEAD 15 M
HP 10000*15*1.2/75*3600
ASSUME 5 HP
COST OF CONSTRUCTION OF SUMP 480 M3 480*3000 1440000 RS
COST OF PUMPING MACHINERY FOR 5 HP 5*5000*2
=50000 RS
ENERGY CHARGES PER YEAR @ RS.5/UNIT 5*24*365*5 RS
=219000
OTHER CHARGES 200000 RS
COST OF PUMP HOUSE FOR 16 SQ. M 16*2500 =40000 RS
TOTAL COST 1749000 RS
Hence it can be seen that capital expenditure incurred stands recoverable within very short period. It can be taken up during the maintenance of the scheme.
Even if the capital cast is taken as the loan, the total repayment is expected within 3 to 3.5 years. However, for capacities more than 25 mld plants recirculation will be more justifiable, but it can be thought of for lesser capacities where there is a scarcity of water in summer and all efforts to save water is a must.
During the daily operations of treatment plant washing of filters is a regular activity. For washing of filters pure water is used and normally it is wasted. In case of higher capacity treatment plants the quantity of wash water wasted is substantial 3% to 5% of the capacity of treatment plant is estimated as waste.
Wash water quantity waste can be minimized by recirculating the waste water by creating an appropriate storage. In case of new treatment plants recirculation can be one of the regular unit and can be simultaneously constructed. However, in case of old treatment plant recirculation feature can be added during maintenance.
Sample calculations are given as below so as to arrive at the economics.
RATE OF FILTRATION 5M3/M2/HR
BED AREA 100M2
MAXIMUM FLOW 12000M3 /DAY
RATE OF BACKWASH 600LIT/M2/MIN
FOR 10 MIN BACKWASH FLOW 600*10*100LIT/DAY 600 M3/DAY
% FLOW OF BACKWASH 5%
ASSUME 80% BACKWASH FOR RECIRCULATION 4% 480 M3/DAY
COST OF RECIRCULATION WATER @ RS. 7.30/M3 480*7.30 = 3504 RS/DAY
REVENUE FROM RECIRCULATION WATER / YEAR 1278960 RS/YEAR
% RECVERY @ 80% OF ABOVE 1023168 RS/YEAR
MINIMUM STORAGE OF RECIRCULATED WATER 480 M3
RATE OF PUMPING 480/24 M3/HR 20 M3/HR
HEAD 15 M
HP 10000*15*1.2/75*3600
ASSUME 5 HP
COST OF CONSTRUCTION OF SUMP 480 M3 480*3000 1440000 RS
COST OF PUMPING MACHINERY FOR 5 HP 5*5000*2
=50000 RS
ENERGY CHARGES PER YEAR @ RS.5/UNIT 5*24*365*5 RS
=219000
OTHER CHARGES 200000 RS
COST OF PUMP HOUSE FOR 16 SQ. M 16*2500 =40000 RS
TOTAL COST 1749000 RS
Hence it can be seen that capital expenditure incurred stands recoverable within very short period. It can be taken up during the maintenance of the scheme.
Even if the capital cast is taken as the loan, the total repayment is expected within 3 to 3.5 years. However, for capacities more than 25 mld plants recirculation will be more justifiable, but it can be thought of for lesser capacities where there is a scarcity of water in summer and all efforts to save water is a must.
Masterpiece
Masterpiece
Problems of distribution system are better known to the maintenance person. He has to do trials and see that the things are set right. He has not to design but convince the simpler methods to the lower staff. In many cases lower staff has the solution. It has to be given correct shape. The background of the process has to be understood. Masterpiece is one such solution. It has not appeared in the books. Seniors do not deny its credibility, but it is not of value to them. Masterpiece has been tried at number of places. It was required to be kept as secret as it is not commonly acceptable. But when results were seen the details were thought of. Masterpiece has no design. Its use is based on experience. On the other hand orifices had some design. The use of orifices was not encouraging. It needed frequent changes. Replacement was not easy. Orifices were struck at valve points only. That is at initial stages only the constriction was proposed. Masterpiece has choice of location. It disturbs continuity of flow. New hydraulics starts from masterpiece and hence, it is more successful.
Concept:
For the design of pipelines in the gravity system, the network is indeterminate, but with some assumptions it can be converted into determinate functions. But there are limitations. While calculating demand, population is multiplied by average LPCD rate. Some peak factor is also considered. System, on this assumption, is required to operate 24 hours, but in practice it does not act accordingly.
System flow is decided by the gravity available and not by the drawal requirement. Hydraulic design does not consider this aspect. It is seen that many a times the velocity of pipe flow is much more than required. This situation is particularly on the sloping ground. Normally from storages outlet diameter is larger one and the resulting drawal capacity is extraneous. On slopes it increases further. On plains, however, the velocity is again slowed down. Hydraulic statement does not take any cognizance of these differential velocities. It calculates the single resultant velocity for the pipe diameter for a particular net head loss. This velocity is irrespective to the length of the pipeline, if minor frictional losses are neglected.
Thus, for long length velocity function is different at different section. The phenomenon is predominant in case of initial empty lines. The chances of emptying the pipeline, in gravity conditions, are frequent. For such conditions, if velocity is required to be controlled, there should be some separate efforts. Such efforts are fruitful with the use of some pipe pieces in the system. Trouble-some gravity system can be easily stabilized with the use of these pieces of pipes and hence, they are termed as master pieces.
What is the trouble in gravity systems? When there is velocity difference in different sections, then naturally a slow moving water column will act as the obstruction to the speedily moving water column. A return wave is expected, at such points. Further, water is heavier than air. On slopes, water gravitates faster. To some extent air also moves downwards with the sweep of water, but gets compressed in the run. It tries to get way through the upper portion of the pipeline. With additional water getting down, equivalent quantity of air wants to go out of system.
For example, suppose 300 mm dia. Pipeline, 600 m in length is continuously sloping at the total loss of head of 30m. The remaining length is flat. Velocity in the sloping portion is of the order of 10 m/sec. Final, resulting velocity is only 0.8m/sec. This indicates that, water column of flat region is comparatively at rest; and hence, tries to obstruct flow impact on slopes. To have the same velocity either pipe diameter has to be reduced or valves are required to be operated. But valve operation can not be relied upon. Instead, pipe diameter can be reduced. It can be reduced at salient points. With some calculations, the diameter reduction can be arrived at, keeping outer diameter same i.e. 300mm. Any lower diameter, say 100mm, 150mm, etc. can be introduced inside. Annular space can be concreted. Minimum length of such piece should be 20 to 30 (d), where d = dia. of smaller pipe. Such concreted piece shall be introduced in the system. Then the same line functions in a different way. It, not only reduces the velocity, but eliminates the troubles due to air blockage. Air can be vented smoothly. Pipe breakage is minimized. Such an exercise can be done on site with very minor set of calculations. Such masterpieces can be used with the combination of air vents, and then the system works very smoothly.
Construction:
For C.I., A.C., and P.V.C pipe lines; approximately 2.5 m length of pipe pieces are used. Outer pipes are equivalent to original pipe diameter. Calculated smaller diameter pipe can be put up-right in the outer pipe, kept vertically. Annular space is concreted and cured. The piece is inserted at suitable locations. Working is checked. If required, some range of such pipe pieces be kept ready and shall be laid along with pre-decided locations of the pipeline to get the required results.
For deeply sloping lines, a regular smaller diameter pipe line is laid and connected to main line after the sloping portion. End of main line is kept open to air and only the smaller diameter pipe is connected to the outlet. Open end works as the natural air valve. Its working is very much satisfactory.
Masterpiece is hidden piece in the system and can not be identified. Externally main pipeline is similar. Jointing system is also as per main line. The master piece once fixed and suited in position works smoothly. It needs no operation. It has no moving parts. Its location should be noted.
Utilization and advantages
Such masterpieces are found very successful in the gravity systems. This has the utilization in distribution system, feeder mains, and Gravity mains. Associated with air shafts the working is very fruitful. The locations can be understood by the lower staff. Introduction is very easy. It needs practically no calculations, if two, three sample trials are taken. The pieces can be prepared easily on site. It needs no extra fittings. The pieces are sturdy and need no maintenance once fitted.
Problems of distribution system are better known to the maintenance person. He has to do trials and see that the things are set right. He has not to design but convince the simpler methods to the lower staff. In many cases lower staff has the solution. It has to be given correct shape. The background of the process has to be understood. Masterpiece is one such solution. It has not appeared in the books. Seniors do not deny its credibility, but it is not of value to them. Masterpiece has been tried at number of places. It was required to be kept as secret as it is not commonly acceptable. But when results were seen the details were thought of. Masterpiece has no design. Its use is based on experience. On the other hand orifices had some design. The use of orifices was not encouraging. It needed frequent changes. Replacement was not easy. Orifices were struck at valve points only. That is at initial stages only the constriction was proposed. Masterpiece has choice of location. It disturbs continuity of flow. New hydraulics starts from masterpiece and hence, it is more successful.
Concept:
For the design of pipelines in the gravity system, the network is indeterminate, but with some assumptions it can be converted into determinate functions. But there are limitations. While calculating demand, population is multiplied by average LPCD rate. Some peak factor is also considered. System, on this assumption, is required to operate 24 hours, but in practice it does not act accordingly.
System flow is decided by the gravity available and not by the drawal requirement. Hydraulic design does not consider this aspect. It is seen that many a times the velocity of pipe flow is much more than required. This situation is particularly on the sloping ground. Normally from storages outlet diameter is larger one and the resulting drawal capacity is extraneous. On slopes it increases further. On plains, however, the velocity is again slowed down. Hydraulic statement does not take any cognizance of these differential velocities. It calculates the single resultant velocity for the pipe diameter for a particular net head loss. This velocity is irrespective to the length of the pipeline, if minor frictional losses are neglected.
Thus, for long length velocity function is different at different section. The phenomenon is predominant in case of initial empty lines. The chances of emptying the pipeline, in gravity conditions, are frequent. For such conditions, if velocity is required to be controlled, there should be some separate efforts. Such efforts are fruitful with the use of some pipe pieces in the system. Trouble-some gravity system can be easily stabilized with the use of these pieces of pipes and hence, they are termed as master pieces.
What is the trouble in gravity systems? When there is velocity difference in different sections, then naturally a slow moving water column will act as the obstruction to the speedily moving water column. A return wave is expected, at such points. Further, water is heavier than air. On slopes, water gravitates faster. To some extent air also moves downwards with the sweep of water, but gets compressed in the run. It tries to get way through the upper portion of the pipeline. With additional water getting down, equivalent quantity of air wants to go out of system.
For example, suppose 300 mm dia. Pipeline, 600 m in length is continuously sloping at the total loss of head of 30m. The remaining length is flat. Velocity in the sloping portion is of the order of 10 m/sec. Final, resulting velocity is only 0.8m/sec. This indicates that, water column of flat region is comparatively at rest; and hence, tries to obstruct flow impact on slopes. To have the same velocity either pipe diameter has to be reduced or valves are required to be operated. But valve operation can not be relied upon. Instead, pipe diameter can be reduced. It can be reduced at salient points. With some calculations, the diameter reduction can be arrived at, keeping outer diameter same i.e. 300mm. Any lower diameter, say 100mm, 150mm, etc. can be introduced inside. Annular space can be concreted. Minimum length of such piece should be 20 to 30 (d), where d = dia. of smaller pipe. Such concreted piece shall be introduced in the system. Then the same line functions in a different way. It, not only reduces the velocity, but eliminates the troubles due to air blockage. Air can be vented smoothly. Pipe breakage is minimized. Such an exercise can be done on site with very minor set of calculations. Such masterpieces can be used with the combination of air vents, and then the system works very smoothly.
Construction:
For C.I., A.C., and P.V.C pipe lines; approximately 2.5 m length of pipe pieces are used. Outer pipes are equivalent to original pipe diameter. Calculated smaller diameter pipe can be put up-right in the outer pipe, kept vertically. Annular space is concreted and cured. The piece is inserted at suitable locations. Working is checked. If required, some range of such pipe pieces be kept ready and shall be laid along with pre-decided locations of the pipeline to get the required results.
For deeply sloping lines, a regular smaller diameter pipe line is laid and connected to main line after the sloping portion. End of main line is kept open to air and only the smaller diameter pipe is connected to the outlet. Open end works as the natural air valve. Its working is very much satisfactory.
Masterpiece is hidden piece in the system and can not be identified. Externally main pipeline is similar. Jointing system is also as per main line. The master piece once fixed and suited in position works smoothly. It needs no operation. It has no moving parts. Its location should be noted.
Utilization and advantages
Such masterpieces are found very successful in the gravity systems. This has the utilization in distribution system, feeder mains, and Gravity mains. Associated with air shafts the working is very fruitful. The locations can be understood by the lower staff. Introduction is very easy. It needs practically no calculations, if two, three sample trials are taken. The pieces can be prepared easily on site. It needs no extra fittings. The pieces are sturdy and need no maintenance once fitted.
COMPUTERIZED WATER BILLING SYSTEM
COMPUTERIZED WATER BILLING SYSTEM
Amaravati water supply scheme is the only urban water supply scheme in Maharashtra which has been getting the facility of computerized water billing system continuously since 1991. The operating of the system has been outsourced. The software development has not been in a year or two, but it has been in process years together and proudly contributed by generously from meter readers, counter clerks, fitters, plumbers, clerical staff in the office, and auditors and accountants, to the higher officers, engineers at all levels, and most of consumers of the scheme. It has become most intelligent software in the country and now it is not only utility software but it is management software. It is in use in number of cities in Vidarbha and has to share the experience of managing more than 800000 consumers in the Delhi, the Capital city of the Country, since 1995. Following script has been included in the Maintenance Manual for urban areas.
Water Billing and Revenue Management System is the most important Aspect of any Water Supply Scheme as it governs the financial aspect, which is the most important factor. The base of Water Billing System can be any one or more of the following:-
A. Metered System
1. Actual Consumption of Water
2. Minimum Fixed Charge
B. Non-Metered System
1. Fixed Charge Per Month
2. Fixed Charge Per Family
3. Fixed Charge Per Tap
4. Percentage of Annual Letting Value of Property
The various stages in the Water Billing Process are:-
1. Data Gathering (Meter Reading in case of Metered Billing)
2. Generation of Bill based on this Data
3. Distribution of Bill to Consumer
4. Payment of the Bill by the Consumer
5. Sending the receipt details to Billing Section
6. Related Accounting
Irrespective of the basis of the Billing Metered/Unmetered, the Computerized Billing System needs Three major databases:-
1. Master Data – This is the data, which needs to be entered only one time when the Consumer/Connection is added into the database. This data is relatively static in nature and does not change time to time. Various data required to be stored are:-
Consumer Number, Name of Consumer, Address, Type of Use, Type of Consumer, Tap Size, Date of Connection, Details of Feeder Line, Locality, House No., Ward No., No. of taps, No. of Families, Meter Make, Meter Number, First Reading, Ownership of Meter, Deposit Amount etc.
2. Data for each Billing Round – This data will be entered for every consumer for every round and will be used for calculating the demand of that billing round. Various data items required to be stored are :–
Consumer Number, Date of Meter Reading/Period for which Billed, Status of the Connection and any changes in Master Data etc.
3. Receipt Data – This data will be the data related to the payments made by the consumers against the bill issued. This data will be entered on daily basis irrespective of the billing frequency. Various data required to be stored are:-
Consumer Number, Date of Receipt, Receipt Number, Details of the collection Centre, Cash/Cheque (If Cheque- Cheque No., Bank, Branch) Part Payment/Adhoc Payment/Deposit, Account Head for posting etc.
BILLING PROCESS:
A. Data Gathering: - For better administrative control over the complete billing process the City/Town is divided into various Zone/Sections geographically or as per the distribution network ESR wise. It is observed that the Cities already have ward numbers or localities which can be used as they are but if the billing is as per the distribution network the billing system can provide very important feed back as far as Water/Revenue losses are concerned (Water Unaccounted for).
These zones are further divided into smaller areas (Wards) for better control. The Person responsible for gathering data from these is the Meter Reader/Ward Clerk. In case of Metered System the suggested Number of Consumers which can be handled by one Meter Reader may vary from 1000 to 1500 Consumers per month depending on the geographical spread of the area and other office jobs to be performed by the person. In case of unmetered System the Number can be doubled.
The prime responsibility of this person will be,
1. to gather all the data related to the water connections in given area,
2. to collect all the data related to New Connections/Disconnection
3. to point out any change in the Master data of these connections.
This person will also be responsible for communicating this data, in given formats to the Billing Section.
B. Generation of Bills:
The Water Rates/Tariff structure may have one or more aspects from the following – Consumption Based, Flat Rate, Minimum Charges, Fixed Charges, Average Consumption Based etc.
Depending on the data gathered the demand for a particular billing period is calculated by the Computerized System. The outstanding amount is worked out on the basis of details of payments received. The charges for delayed payments or amounts not paid are calculated as per the rules given and the Bills are generated areawise.
C. Distribution of Bills to Consumer:
The distribution of bills can be done using any one of the following
a. By Post or Courier
b. By Persons specially appointed for this purpose
c. By Concerned Meter Readers/Ward Clerks
i) In a special round for distribution of bills
ii) At the time of Meter Reading for next round.
(This option saves effort/manpower but there is delay on one complete cycle in meter reading and distribution of bills)
D. Payment of Bills by the Consumer
The payments can be accepted at any one or more of the following:
a. Counters at various offices of the Board/Corporation
b. Various branches of Bank/Banks authorized for accepting payments
c. Door to door/on the spot recovery by concerned person/team.
d. Electronic fund transfer through various banks offering such option
E. Sending Receipt Details to Billing Section:
The collection counter/Bank/person shall send the receipt details to the billing section periodically (preferably daily basis) and the same is entered into the system and the totals cross checked.
F. Related Accounting:
The billing section also carries out the accounting related to these receipts such as posting of receipts, generation of demand registers or ledgers on periodic basis. The complete accounting related to the Billing is to be carried out by computerized system.
FREQUENCY OF BILLING
The frequency of Billing governs the cash flow of the Water billing system and thus more frequency means regular cash flow. The frequency of billing depends mainly on the type of system used. For Non-metered system the suggested Billing frequency is quarterly and for the Metered Systems the suggested Billing frequency is Bi-monthly. But in both cases all Non-Domestic, Industrial, Bulk Consumers shall preferably by billed Monthly to have a better control. The only other factor which can be considered in the respect is the availability of manpower for billing process and the cost of issuing bills in one complete billing etc.
DELAYED PAYMENTS:
Since water is being treated as a commodity consumed the advance billing is generally not carried out. It is therefore must to levy penalty/interest on the delayed payments of the bills. The minimum rate for such Delayed payments shall be at per with commercial interest rate.
COMPUTERISATION OF WATER BILLING SYSTEM
In this twenty first century Computers have become necessary in the day to day activities also. For the water billing system which is complex, repetitive and has voluminous data, computerization is must. Since various related areas like accounting, banking, consumer services are already computerized at most of the places computerization of the water billing is must.
REQUIREMENTS OF COMPUTERISED WATER BILLING SYSTEM
a. Hardware:- The Computer Hardware required for Water Billing System is as follows:
i) For Towns with 25,000 or less Water Connections the requirements of Hardware for processing of 5,000 Bills Per Month is as follows:-
P-III, 850+MHz, 64 MBRAM, 20GB HDD, 1.44 MB FDD, 2 Nos. 52x CD-ROM, SVGA MONITOR, KEYBOARD, MOUSE etc.
DOT MATRIX PRINTERS 300+ C.P.S., 132 Column – 2 Nos.
U.P.S. 1 KVA (At least 30 minutes battery backup) – 2 Nos.
ii) For Cities with more than 25,000 Water Connections requirement for processing 25,000 Bills Per Month is as follows:-
SERVER – P-4, 1+Ghz, 256 MB RAM, 2x20+ GB SCSI HDD, 1 No.
1.44 MB FDD, 52X CD-ROM, 8/16 GB DAT, SVGA MONITOR, KEYBOARD, MOUSE, ETHERNET CARD, 56.6 KBPS MODEM etc. P-III, 850+MHz, 64 MB RAM, 20 GB HDD, 1.44 MB FD, - 10 Nos. 52X CD-ROM, SVGA MONITOR, KEYBOARD, ETHERNET CARD, MOUSE etc.
16 PORT HUB - 1 No.
LINE PRINTER 1400 LPM - 1 No.
DOT MATRIX PRINTERS 300+C.P.S., 132 Column - 5 Nos.
U.P.S. 5 KVA (At least 30 minutes battery backup) - 1 No.
iii) For Metros with more than 1,00,000 Water Connections requirement the Hardware Setup mentioned in (ii) above needs to be installed at various Zonal Offices and these Servers be interconnected to each other for Data transfer or generation of reports.
b. System Software: The System Software required is as follows:
i) For Towns using stand along Computer systems the System Software required is Windows, FOXPRO
ii) For Cities and Metros using Servers the System Software is as follows:
Windows, UNIX, ORACLE, DEVELOPER 2000 or Visual Basic
c. Application Software: - The Application Software for the Water Billing System is the soul of the Computerized Water Billing System and needs to be developed as per the requirement of the Board/Urban Local Body.
d. Manpower:- The manpower required for the Computerized Water Billing System is as follows:-
i) Manager Data Processing – 1 No. for each Computer Centre
ii) Supervisor Data Processing – 2 Nos. for each Computer Centre
iii) Data Entry Operators – 1 No. for each Computer
PRIVATISATION:
Considering the volume of the work and skills required for the Computer Operations this activity can be entrusted to a private Agency on Contract basis. The Contract can be for complete Out-Sourcing or Data Processing or Deputing Expert Manpower for On – Site Data processing.
ADVANTAGES OF COMPUTERIZATION:
Control of the System
Decision Making
Sky is the limit
FUTURE AVENUES:
The Computerized Water Billing System can be used in future for direct payments through Credit Cards, Internet etc. The information for the consumers can also be made available on Internet or through Kiosks. The advance meters with remote reading techniques may give a system with minimum data entry to be done manually. The distribution network if available as Graphic information on Computers, can be directly be linked with the billing system to locate Water/Revenue losses.
OUTPUT FORMATS:
1. BILL: On Computer Stationary of 15” x 6” Size having three distinct parts which are separated by perforation for easy tear off. The data printed on all three parts is same. The first of leftmost part acts as acknowledgement of the Consumer for having received the bill for and also office copy of the bill issued. The Second or middle part is the Bill Cum Receipt for the consumer. The Third or rightmost part is the copy of the receipt given to consumer for the collection centre.
The contents of the bill are – Period of Billing, Zone, Area, Bill date, Due Date, Bill Number, Consumer No., Consumer Name, Address, Water Charge, Arrears, D.P.C., Meter Details, Previous & Current Reading, Status of Meter, Tap Size, Consumer Type, and Last Payment Details etc.
2. METER READING BOOK:
Consumer No., Name, Previous Reading & Status, Current Reading & Status
3. SCROLL
Receipt No., Date, Collection Centre, Consumer No., Name, Area, Amount,
Cheque Details etc.
4. LEDGER
Consumer No., Name, Outstanding amount as on 1st April and following details of each billing round in the year –
Current Reading & Status, Arrears, D.P.C., Water Charge, Receipt No., Date, Amount received.
5. ASSESSMENT / DEMAND
Zone, Area, Meter Reader, Total Water, Total D.P.C.
6. DEFAULTERS LIST
Consumer No., Name, Outstanding Amount, Last Payment Date, Status
7. DISCONNECTION LIST:
Meter Reader, Area, Consumer No., Name, Outstanding Amount
Amaravati water supply scheme is the only urban water supply scheme in Maharashtra which has been getting the facility of computerized water billing system continuously since 1991. The operating of the system has been outsourced. The software development has not been in a year or two, but it has been in process years together and proudly contributed by generously from meter readers, counter clerks, fitters, plumbers, clerical staff in the office, and auditors and accountants, to the higher officers, engineers at all levels, and most of consumers of the scheme. It has become most intelligent software in the country and now it is not only utility software but it is management software. It is in use in number of cities in Vidarbha and has to share the experience of managing more than 800000 consumers in the Delhi, the Capital city of the Country, since 1995. Following script has been included in the Maintenance Manual for urban areas.
Water Billing and Revenue Management System is the most important Aspect of any Water Supply Scheme as it governs the financial aspect, which is the most important factor. The base of Water Billing System can be any one or more of the following:-
A. Metered System
1. Actual Consumption of Water
2. Minimum Fixed Charge
B. Non-Metered System
1. Fixed Charge Per Month
2. Fixed Charge Per Family
3. Fixed Charge Per Tap
4. Percentage of Annual Letting Value of Property
The various stages in the Water Billing Process are:-
1. Data Gathering (Meter Reading in case of Metered Billing)
2. Generation of Bill based on this Data
3. Distribution of Bill to Consumer
4. Payment of the Bill by the Consumer
5. Sending the receipt details to Billing Section
6. Related Accounting
Irrespective of the basis of the Billing Metered/Unmetered, the Computerized Billing System needs Three major databases:-
1. Master Data – This is the data, which needs to be entered only one time when the Consumer/Connection is added into the database. This data is relatively static in nature and does not change time to time. Various data required to be stored are:-
Consumer Number, Name of Consumer, Address, Type of Use, Type of Consumer, Tap Size, Date of Connection, Details of Feeder Line, Locality, House No., Ward No., No. of taps, No. of Families, Meter Make, Meter Number, First Reading, Ownership of Meter, Deposit Amount etc.
2. Data for each Billing Round – This data will be entered for every consumer for every round and will be used for calculating the demand of that billing round. Various data items required to be stored are :–
Consumer Number, Date of Meter Reading/Period for which Billed, Status of the Connection and any changes in Master Data etc.
3. Receipt Data – This data will be the data related to the payments made by the consumers against the bill issued. This data will be entered on daily basis irrespective of the billing frequency. Various data required to be stored are:-
Consumer Number, Date of Receipt, Receipt Number, Details of the collection Centre, Cash/Cheque (If Cheque- Cheque No., Bank, Branch) Part Payment/Adhoc Payment/Deposit, Account Head for posting etc.
BILLING PROCESS:
A. Data Gathering: - For better administrative control over the complete billing process the City/Town is divided into various Zone/Sections geographically or as per the distribution network ESR wise. It is observed that the Cities already have ward numbers or localities which can be used as they are but if the billing is as per the distribution network the billing system can provide very important feed back as far as Water/Revenue losses are concerned (Water Unaccounted for).
These zones are further divided into smaller areas (Wards) for better control. The Person responsible for gathering data from these is the Meter Reader/Ward Clerk. In case of Metered System the suggested Number of Consumers which can be handled by one Meter Reader may vary from 1000 to 1500 Consumers per month depending on the geographical spread of the area and other office jobs to be performed by the person. In case of unmetered System the Number can be doubled.
The prime responsibility of this person will be,
1. to gather all the data related to the water connections in given area,
2. to collect all the data related to New Connections/Disconnection
3. to point out any change in the Master data of these connections.
This person will also be responsible for communicating this data, in given formats to the Billing Section.
B. Generation of Bills:
The Water Rates/Tariff structure may have one or more aspects from the following – Consumption Based, Flat Rate, Minimum Charges, Fixed Charges, Average Consumption Based etc.
Depending on the data gathered the demand for a particular billing period is calculated by the Computerized System. The outstanding amount is worked out on the basis of details of payments received. The charges for delayed payments or amounts not paid are calculated as per the rules given and the Bills are generated areawise.
C. Distribution of Bills to Consumer:
The distribution of bills can be done using any one of the following
a. By Post or Courier
b. By Persons specially appointed for this purpose
c. By Concerned Meter Readers/Ward Clerks
i) In a special round for distribution of bills
ii) At the time of Meter Reading for next round.
(This option saves effort/manpower but there is delay on one complete cycle in meter reading and distribution of bills)
D. Payment of Bills by the Consumer
The payments can be accepted at any one or more of the following:
a. Counters at various offices of the Board/Corporation
b. Various branches of Bank/Banks authorized for accepting payments
c. Door to door/on the spot recovery by concerned person/team.
d. Electronic fund transfer through various banks offering such option
E. Sending Receipt Details to Billing Section:
The collection counter/Bank/person shall send the receipt details to the billing section periodically (preferably daily basis) and the same is entered into the system and the totals cross checked.
F. Related Accounting:
The billing section also carries out the accounting related to these receipts such as posting of receipts, generation of demand registers or ledgers on periodic basis. The complete accounting related to the Billing is to be carried out by computerized system.
FREQUENCY OF BILLING
The frequency of Billing governs the cash flow of the Water billing system and thus more frequency means regular cash flow. The frequency of billing depends mainly on the type of system used. For Non-metered system the suggested Billing frequency is quarterly and for the Metered Systems the suggested Billing frequency is Bi-monthly. But in both cases all Non-Domestic, Industrial, Bulk Consumers shall preferably by billed Monthly to have a better control. The only other factor which can be considered in the respect is the availability of manpower for billing process and the cost of issuing bills in one complete billing etc.
DELAYED PAYMENTS:
Since water is being treated as a commodity consumed the advance billing is generally not carried out. It is therefore must to levy penalty/interest on the delayed payments of the bills. The minimum rate for such Delayed payments shall be at per with commercial interest rate.
COMPUTERISATION OF WATER BILLING SYSTEM
In this twenty first century Computers have become necessary in the day to day activities also. For the water billing system which is complex, repetitive and has voluminous data, computerization is must. Since various related areas like accounting, banking, consumer services are already computerized at most of the places computerization of the water billing is must.
REQUIREMENTS OF COMPUTERISED WATER BILLING SYSTEM
a. Hardware:- The Computer Hardware required for Water Billing System is as follows:
i) For Towns with 25,000 or less Water Connections the requirements of Hardware for processing of 5,000 Bills Per Month is as follows:-
P-III, 850+MHz, 64 MBRAM, 20GB HDD, 1.44 MB FDD, 2 Nos. 52x CD-ROM, SVGA MONITOR, KEYBOARD, MOUSE etc.
DOT MATRIX PRINTERS 300+ C.P.S., 132 Column – 2 Nos.
U.P.S. 1 KVA (At least 30 minutes battery backup) – 2 Nos.
ii) For Cities with more than 25,000 Water Connections requirement for processing 25,000 Bills Per Month is as follows:-
SERVER – P-4, 1+Ghz, 256 MB RAM, 2x20+ GB SCSI HDD, 1 No.
1.44 MB FDD, 52X CD-ROM, 8/16 GB DAT, SVGA MONITOR, KEYBOARD, MOUSE, ETHERNET CARD, 56.6 KBPS MODEM etc. P-III, 850+MHz, 64 MB RAM, 20 GB HDD, 1.44 MB FD, - 10 Nos. 52X CD-ROM, SVGA MONITOR, KEYBOARD, ETHERNET CARD, MOUSE etc.
16 PORT HUB - 1 No.
LINE PRINTER 1400 LPM - 1 No.
DOT MATRIX PRINTERS 300+C.P.S., 132 Column - 5 Nos.
U.P.S. 5 KVA (At least 30 minutes battery backup) - 1 No.
iii) For Metros with more than 1,00,000 Water Connections requirement the Hardware Setup mentioned in (ii) above needs to be installed at various Zonal Offices and these Servers be interconnected to each other for Data transfer or generation of reports.
b. System Software: The System Software required is as follows:
i) For Towns using stand along Computer systems the System Software required is Windows, FOXPRO
ii) For Cities and Metros using Servers the System Software is as follows:
Windows, UNIX, ORACLE, DEVELOPER 2000 or Visual Basic
c. Application Software: - The Application Software for the Water Billing System is the soul of the Computerized Water Billing System and needs to be developed as per the requirement of the Board/Urban Local Body.
d. Manpower:- The manpower required for the Computerized Water Billing System is as follows:-
i) Manager Data Processing – 1 No. for each Computer Centre
ii) Supervisor Data Processing – 2 Nos. for each Computer Centre
iii) Data Entry Operators – 1 No. for each Computer
PRIVATISATION:
Considering the volume of the work and skills required for the Computer Operations this activity can be entrusted to a private Agency on Contract basis. The Contract can be for complete Out-Sourcing or Data Processing or Deputing Expert Manpower for On – Site Data processing.
ADVANTAGES OF COMPUTERIZATION:
Control of the System
Decision Making
Sky is the limit
FUTURE AVENUES:
The Computerized Water Billing System can be used in future for direct payments through Credit Cards, Internet etc. The information for the consumers can also be made available on Internet or through Kiosks. The advance meters with remote reading techniques may give a system with minimum data entry to be done manually. The distribution network if available as Graphic information on Computers, can be directly be linked with the billing system to locate Water/Revenue losses.
OUTPUT FORMATS:
1. BILL: On Computer Stationary of 15” x 6” Size having three distinct parts which are separated by perforation for easy tear off. The data printed on all three parts is same. The first of leftmost part acts as acknowledgement of the Consumer for having received the bill for and also office copy of the bill issued. The Second or middle part is the Bill Cum Receipt for the consumer. The Third or rightmost part is the copy of the receipt given to consumer for the collection centre.
The contents of the bill are – Period of Billing, Zone, Area, Bill date, Due Date, Bill Number, Consumer No., Consumer Name, Address, Water Charge, Arrears, D.P.C., Meter Details, Previous & Current Reading, Status of Meter, Tap Size, Consumer Type, and Last Payment Details etc.
2. METER READING BOOK:
Consumer No., Name, Previous Reading & Status, Current Reading & Status
3. SCROLL
Receipt No., Date, Collection Centre, Consumer No., Name, Area, Amount,
Cheque Details etc.
4. LEDGER
Consumer No., Name, Outstanding amount as on 1st April and following details of each billing round in the year –
Current Reading & Status, Arrears, D.P.C., Water Charge, Receipt No., Date, Amount received.
5. ASSESSMENT / DEMAND
Zone, Area, Meter Reader, Total Water, Total D.P.C.
6. DEFAULTERS LIST
Consumer No., Name, Outstanding Amount, Last Payment Date, Status
7. DISCONNECTION LIST:
Meter Reader, Area, Consumer No., Name, Outstanding Amount
Amaravati water supply scheme
Amaravati water supply scheme
Physical and financial
Introduction
Amaravati water supply from Upper Wardha Dam as a source is in operation successfully since March 1994. As per audit report 1998-99 it was a finding that there was a hydraulic loss of 56% in the system, as a whole. At that time 6 no. of ESRs were under construction and not in operation. One by one these ESRs were put into operation. 56% losses in the overall system refer to the period before additional 5 ESRs were put into in operation. Every ESR has its own distribution system, which might have been additionally laid or contributed from the existing distribution system. This distribution system was to be laid for the equitable water supply to the city. During the process of phase of execution, continued efforts were being done to restrict the losses to the bear minimum. These efforts should go on continuously. Reported losses in 2003-04 are 21.82%, indicating substantial reduction by 34%.
Influence zones
Concept of influence zone of ESR has not been tried elsewhere on field. No reports are available of having efficient distribution by adding the no. of ESRs in the existing network. Amaravati has initially only Maltekadi as GSRs in two zones, working in the radious of 14 kms. After some years 4 new ESRs were put into operation. Apart from their storage capacity, their elevation decided the influence zone. In those days (1987-89) Whole City was dependent on ground water as a source. There was water shortage. Approximately, 65 LPCD water was distributed. System had much higher capacity.
From Maltekadi, when the water was let out to the system, system volume being much higher there was quick drop of level in the storage and also the system pressures. Improvement was seen, due to zonal ESRs, (VMV 15 lakh lit.,Nagpuri gate 20 lakh lit.). They were constructed at the rear end of the Maletekadi influence zone and tried to be fed from REOSA tube well water by laying separate rising mains. Overall quantity of water reaching to the City was the same and still the effect was seen positive in terms of increase of system pressures at the influence zones of new ESRs.
Subsequently, in the new sanctioned estimate for the Distribution system, additional 6 no. of ESRs were proposed to be constructed. 7 ESRs/GSRs were already existing. All these ESRs are at the periphery of the city. Total storage capacity of these ESRs is 120 lakhs.
Old Maltekadi 50 lakhs
50 lakhs
Badnera 12 lakhs
VMV, Nagpuri gate,
Bhimtekadi, Saturna 75 lakhs
Arjunnagar, Paradise colony
Mayanagar, Badnera New 80 lakhs
Wadali, Wadarpura 20 lakhs
Tapovan MBR 33 lakhs
Tapovan hsr 20 lakhs
Total 340 lakhs
For effective distribution Tapovan storages very near to the treatment plant are to be deducted. Available storage is (340-33-20) 287 lakh lit.
ESR duty
Population as per 2001 Census is 549500 souls. Prospective populations after 15 years will be approximately 860000 souls. Consumptive demand will be 120 ml/day. With losses at 15 % it will be 138 ml/day. For this purpose average ESR duty will be 1380/287 = 4.80. This figure is more than the design value. Hence, it is required to increase the storage to 460 lakh lit. This means that additional (460-287)173 lakh lit storage has to be increased in a phased manner. Or use of Tapovan GSRs can be made for direct distribution system. Irrespective of capacity of ESR, if the longer lengths are to be fed to the distribution system, losses in reaching the consumers will substantially reduce the pressures. This will give rise to the unsatisfactory service levels. This can be reflected financially also.
ESR duty up to 2.8 to 3 can be achieved by adding the additional outlets to the existing and newly constructed ESRs. Further, influence zone of ESRs shall be limited to encircled area of having a radius of 1.8 km.
Marking these influence zones on the distribution map, will reveal the location of new ESRs.
ESR capacity
ESR duty round about 3 in the ultimate stage, means that 3 fillings of ESR. For 20 lakhs capacity it is 60 lakhs lit. Assume, it corresponds to 50000 souls of population. In the zone of influnce,1.8 km is assumed as radius. For safety factor there should be 15% envelope area of adjoining zones. Area of influence zone comes to 1017 ha. Assuming 15 % envelope area this reduces to approximately 865 ha. If 50000 souls are getting accommodated in the influence zone, then the population density comes to about 55 persons per ha. This fairly matches with horizontally developing city areas of Vidarbha. Regarding capacity of ESR, it can be decided as following. Demand comes to 50000 * 120 =60 lakh lit. Ideal losses at 15 % in the distribution system can be added. Hence, demand comes to 72 lakh lit with 20 hr working and 3 as duty, appropriate ESR capacity comes to 25 lakhs. If the hector density is more the storage capacity shall change.
All these principles have not been tested in any city. Amaravati distrbution is developing since 1960.upto now more than 650 km of pipelines are laid in the town during various time periods.
Regulatory measures
Till the above factors do not tally, the losses will be maximum compared to the consumption. The revenue losses are based on the realized revenue. Billed quantity is identifiable in case of working meters. However, in the system % of working meters is always less. In case of Amaravati City working meter % is about 70%. In such cases billing is based on average consumption, minimum consumption or any amicable derivation not related to the actual supplied quantity of water. Hence, whatever is assessment; it is converted into hydraulic quantity. This is possible with the help of computerized data of consumer connections. This is rarely available in other cities. It has become unique feature of Amaravati water supply, as this data is available in Amaravati for last 15 years. Inadvertently, field staff supplied quantity of water, without any logical control. Naturally, supplied quantity was much more in comparison with the billed quantity. Meter reading staff was also not guided for the frequent checks that they are required to observe. Initially it was a task to discuss with the field and meter reading staff and tell them the logic to minimize the system losses.
First reaction is always negative and they may not understand the importance of control measures. Supplied water is a valuable commodity and it has to be distributed for the fruitful use and not for waste. Wastage of water is a financial loss. The water available is not unlimited. It should be supplied on some calculations and it has to be checked whether these calculations are correct to realize the revenue. Field staff was asked for controlling the incoming quantity of water to ESRs. It was against the normal trend and offered intrinsic resistance from the staff. But the views were to be canvassed frequently. It took about 4 to 5 years to come to an asymptotic behavior of the demand. Once this end has been seen to be approaching, system theoretically should run in the profit. Staff did co-operate further, as they could realize that they have contributed to the profit, by adopting more scientific view in the water supply management. For such quantity audit, a high profile proposal would have prepared by any external consultant, leaving the all-soft part to the staff and administration. Still the results would not have been so encouraging as in Amaravati. Another indicator is population to connection ratio. It should approach to 10. If it is maintained at that level, profits are assured. When it reaches to less than 7 it will completely refund loan.
Computerized billing process
Computerization of the billing process has been the plus point of the Amaravati water supply scheme. The software is most user friendly and has become intelligent, during continuous use, since last 12 years. In last 12 years it has faced, all receipt and expenditure audit. It has produced all sorts of accounts and information to the audit. It is capable of analyzing the performance of meter readers in their beats, since 1997. Various meetings were held of all concerned meter readers, counter clerks, fitters, section officers, to evaluate their performance with the help of computer data. They were guided to perform better. Targets were given and seen whether they have been achieved. With the computerization, there was better control over the billing cycle of all 55000consumers. For maximization of the revenue, the assessment should be raised.. Billing should be for all 6 bi-months in the year. Revenue from higher size connections were particularly watched in the meetings.
To make best use of the computerization already existing, following things are required,
* Prepare maps of the ESR zones. Give line Identification no. Branches may also be shown and be numbered.
* Consumer number may be modified based on the above data. It may be alphanumeric. such as " sa bc24 5 045678 "
* It reflects for Saturna ESR, line - bc, 24th branch, 5th connection.
* This unique number has to be entered in the bill process. immediately.
* Assign these numbers to the consumers.
* At any time location of the consumer is traced.
* Total number of bills in the ESR zone will be known to anybody
Exact demand on the zone can be estimated accurately.
* Control over the meter-readers will be increased.
* After allotting these numbers all other information can be fed to the computer by creating some additional fields to the database.
* Featural analysis can be available any time from the computers.
* Technical decision has to be guided through computer.
Energy saving
By keeping power factor at 0.99, a rebate can be availed from MSEB. For that purpose peak hour pumping is being avoided. This is rational. It is leading to energy saving and also economical. The efforts taken by mechanical wing are worth appreciating.
Regarding indirect saving in the water quantity not pumped to the city, is also energy saving criteria. But it is more conspicuous when the extra quantity, which otherwise would have been wasted, is conserved as a useful storage in the reservoir itself. Wasted water has production value of pure water. This whole water, if sold to the consumers, would have fetched lakhs of rupees. It has traveled to the doorsteps of the consumers but not billed, and as such unaccounted. Following table will give the idea of indirect saving.
Hence, it was a good step to come close to the actual water consumption of the consumers. Since 1999-00 to this date the efforts are on, to reduce the pumping from Simbhora. Even though, the water demand was increasing, day by day, population has been increasing and the connections are also increasing. Thereby the demand for water was also increasing. In the year 2002-03 more than 3000 connections were increased, Still, there is constant reduction in pumping, indicating the increasing efficiency of the system and that of the staff. It indicates that indirect saving would have been much more. Nobody can work in isolation to give the system efficiency improved. It is conscious, combined, elaborate and unidirected efforts put into to achieve the targets with full understanding. For canvassing this hourly levels and day to day supply, record has been generated and displayed the results in various meetings with the staff, so as to make them appraised of the fact that, things are going on the right track.
Effective control on the incoming water quantity has not affected the revenue; instead it has increased, year by year. Seeing the actual figures, contribution from staff was increased. A statement for supply on each day during years from 98 –99 to 2003-04 will give an idea of as to how the supply was matched with actual demand and ultimately effected in indirect saving. Total saving in ml/year and cost of water saved indirectly per year shown separately.
Financial status
Amaravati water supply scheme has been handed over for maintenance by Amaravati Municipal Corporation on 9-8-1983. Since then scheme has been under control of Maharashtra Jeevan Pradhikaran from source to consumer. At the time of handing over there were only 14000 connections out of which about 4000 connections were un-metered and in addition there were about 1000 standposts in the city. Scheme was running in loss. Expenditure on salary was much more. It was dependent on Pedhi, Purna river sources and the reliability of these sources had come down drastically. Moreover, 110 workers borne on the scheme were brought on CRT and sent to MJP along with the scheme. Old sources, Chatri Talao and Wadali Talao were handed over to MJP for M&R.
.
Systematic efforts were put in to reduce the expenses and to increase the revenue. For this purpose complete analysis of the distribution system was done based on the computer data. Demands from each area were analyzed and its trends were studied. Augmentation as well as improvement schemes were executed during this process. Augmentation scheme was complete by March 1994. Improvement to distribution was complete by 2001. Water was available from Upper Wardha Dam. Source was not a problem. Rational distribution was still a problem. To asses the new level of service, 100% house to house consumer survey was done and analyzed. Demands were reworked out and related to supply side for broader control at Old and New ESR points.
Statement of assessment, revenue and expenditure year wise will clarify the financial status. It can be seen that profit has not accrued till 2001-02 as compared to revenue. But since then, profit is the trend. Technological improvement has more concern to the profit in comparison to cutting expenditure by audit. Technology, sincerely applied goes long way. While rationalizing the supply it was aimed not to bring down the revenue. These efforts took four to five years to give the required results. As it was a soft part to train the meter readers, fitters, valvemen, supervisors and finally engineers. Consumers were also increasing in number and the demands also were increasing but still they were involved in the process by educating the meaning of the bylaws and rules for the billing process. For this purpose years computerization of the billing process helped to sort out the grievances of the consumers and redressels in the various forums. In last 25 years of management assessment, realization figures are increased 25 times, with profit peeing in after 20 years.
It can be revealed that to reduce the expenditure it is required to concentrate on energy cost. Separate attention was given to study the measures to reduce the expenditure. Major concentration was to reduce the pumping head so as to increase the discharge keeping the pumps as installed originally in the year 1993.Discharge was really increased.
With the adaptation of two measures there is a reduction in the head to the minimum of 20 m and the discharge was increased by about 35000 lit per hour for single pump application. System is always run for 24 hours. Naturally it was possible to plan for pumping at night hours more to get the benefit of subsidized rate per unit consumption.
Institutional efficiency
It is required to compile the hour to hour levels recorded for the various ESRs in the city. Total day's supply is also compiled. Comparison of the days supply with the supply made to the city in the earlier year. This comparison can be made for 4 years before. It can be seen that attempts are continuous to get the control over the supply year by year. Till the time when the supply remains constant or at par with the previous years’ supply, there is always a scope to improve. Results can be seen. Deciding the influence zones of the ESRs in the city, it was possible to identify the population served on the particular ESR. The demand and duty assigned to the ESR can be ascertained. For all the section officers the task was given to control the outgoing from ESR to be matching with demand from the relevant population. For want of better instrumentation, this was done from the previous data, and application was done manually. It took lot of time to stabilize the demands and duties of all the ESRs in the city. When the system was stabilized confidence level of the field staff was increased. Reporting and control management was improved. During the periodical meetings this exercise was discussed with field staff and they were shown the results in the saving in quantity of water. They were encouraged to suggest their own methods for further improvement. They were assessed and upheld. Due recognition was given to the field staff in the various functions for their good contribution in the process. From valve operator to section officer, all were “level conscious” as far the ESRs is concerned.
Before this indicator was in force there was no control over the water supply to the city. Day by day the demand is increasing and still the supply is getting reduced, is indicator to reduce the hydraulic losses.
Assessment increase measures
Increase in the assessment is mainly due to finding out the unauthorized stand post connections taken by Municipal Corporation. Corporation normally denies that they have taken the connections but still they exist. They are not on the record. Hence, it is not billed. Thereby it is a loss of revenue. Corporation may suggest that Pradhikaran can disconnect the connection. But, it is the user authority who is required to take the action, by giving notice to the local people surrounding the stand post area. Pradhikaran may take action after corporation has taken necessary steps. When unauthorized stand posts are taken on record the revenue will go on increasing. The bills are given with retrospective effect. These arrears are to be included in the basic records of corporation.
It is in the interest of the corporation to disconnect the stand posts, which are very less used but being charged at the constant rate by Pradhikaran. Disconnection shall be with the alternative that all nearby users can have the house connections given by the Pradhikaran. in that case the bills are being paid by the users and not by the Corporation. Hence, the Corporation, as well as, Pradhikaran is benefited. Statement of disconnected stand posts and recording unauthorized stand posts is enclosed and how the assessment has effected.
Professionals, doctors, etc., have been identified to be applied with non-domestic rates. House to house survey had been conducted. This survey had been conducted, by the staff of Pradhikaran. Irregular connections have been identified. In the survey level of service was recorded. In some cases 24 hour water was identified and in some cases, one hour supply was seen. For having equitable distribution necessary planning has been made. Irregular connections have been tried to be regularized. With all this, assessment has been increased substantially. Statement for such efforts is enclosed.
Efficiency increase tools
"Who pays" analysis from the computer has been very interesting. It was observed that normal regular payers are from the low income groups. In case of higher size connections, either the meters were out of order or the meters were not in position. Bills are found to be going on lower averages which recorded long back when the supplies were inadequate. This analysis also gives the inefficient meter readers, who were slack in delivering the bills. It results into less revenue. A sample statement is enclosed herewith.
Monthly receipts are tallied with the cash book figures. With 50000 connections of the scheme support from the computers is a must. This gives a cross check. Receipts are mainly through co-op. Bank. Similarly, assessment is given meter-reader wise. Computer gives an abstract of the status of the meters. The area in which nonworking meters are functioning, it has to be watched closely. It is very likely that consumers are happy with paying, at the flat rates, that is indicating higher supply area and more wastage. Line valves are required to be adjusted. A sample can be given to illustrate this point.
Cross checking by the totally different staff by directly contacting the consumers and asking their reactions, keeps a better control over the meter-readers. Changing areas or beats of the meter readers also becomes effective but there is a large proportion of resistance from the staff.
External contribution
Pradhikaran has allowed using the services of Co-op. bank for collection of revenue. It has five branches in the city. For 50000 consumers and 6 bills per consumer, in a year, maximum charges are Rs.300000/- per year. For computerization of bills it is rs.720000/- per year. Hence, total services taken externally are required to be paid up to Rs. 1020000/- per year. Expenditure on both these items is revenue expenditure. In terms of percentage it is hardly 1% of the revenue. Lot of thinking man days have been put into. It has not emerged into software as readymade. It is a customized software. Over a period it has become most utilizable and the intelligent software. Our staff means the same staff from the subdivision who is involved in the billing process. It is always better that the third agency is involved in the process so that there is always a countercheck on the happenings on the billing process. These counterchecks have been introduced in the software. The officer concerned, should make use of capabilities of software. There are other software in the field, but to get the equivalent transparency they need a long voyage. This software has been tested by every receipt audit. It has given all records. Software which was previously only used for billing is working at the same rates for receipts also. Naturally, it has the capability for developing the consumer wise, area wise, beat wise, month wise, abstracts and can create annual reports. Manually it is possible but considering the huge number of connections, it is always lagging. Vertical totals are sparingly correct. It is understood that these accounts should be kept manually. But it should be appreciated that earned revenue of crores of Rs. is entitled to have the computer cross check. Expenditure on the ledger creation will be only Rs.40,000/-. It is just .04% of the revenue. It will update everything. It will support the working of staff. All staff are not equal. Any fraudulent tendency can be curbed through cross check. For last such incidences, computer had come to the help and used by office to crystallize the extent of such activity. It had been the practice to tally the monthly receipt account with the cash book. Audit may think of keeping the process online. Install computers in the Subdivision, Division. It may cost something, but it is relevant to push the things ahead.
Internal economy
Over a period number of consumers has been increased substantially. For 56000 consumers and bimonthly billing 25 meter readers are required. But without appointing any external persons the job has been carried out by drafting equivalent trade wokers as meter readers. These were working as counter clerks, karkoons etc. they were released from their assignment as receipts were given to co-op. Bank. Extra expenditure was saved. It has the capacity to handle even more increase in the consumers. New tender now includes the condition that agency can further update the software into oracle, if required, to handle still better. Expenditure on establishment is given year wise and the trend may be noted.
It has started with the issue of system losses. They had compared the incoming water quantity to the billed quantity. This quantity was by computer by calculating reverse from the rate at which they were billed. Hydraulic quantity was compared with quantity derived from financial bills. Basically, these two are separate entities. Still, this was taken as a task. It took 3 years to get some positive results but now the trend is set. Following table will clarify the point.
Year Pumped Supplied % loss Remarks
1997-98 20.04 mcum 11.70 mcum 41.62 % loss
1998-99 22.00 mcum 11.70 mcum 46.82 % loss
1999-00 20.94 mcum 11.47 mcum 45.22 % loss
2000-01 23.37 mcum 10.28 mcum 56.01 % loss Maximum
2001-02 21.33 mcum 14.53 mcum 32.04 % loss Reduction 23.97 %
2002-03 21.28 mcum 16.18 mcum 23.97 % loss Reduction 32.04 %
2003-04 16.43 mcum 12.95 mcum 21.82 % loss Reduction34.19 %
Whole exercise was to improve the efficiency of the system. It has elaborated the answer for the improvement gateway. The lead has been taken to find out the root cause with the help of same available staff and guided them to go ahead on positive way, which is techno economical and professional too. Adding some more ESRs in the system has rationalized the system supply and has contributed in reducing the losses.
Immediate plans
Four new ESRs have been proposed and they are under construction with some addition of distribution system. Effect of which can be seen in coming two years. Methods have been logically imparted to all the field staff and that is the main success of the exercise.
24X7
When the losses have been controlled, it is a good base to take up the 24x7 water supply. It is not possible to apply to whole of the city as in old areas stand post supply still prevails. In this area 24x7 supply means the increase in the wastage. Hence, selection of new area has been done. In Arjunnagar area water supply is mainly on connections. In this area also trial is being taken on one outlet at the first instance. The details of the area are given below in the table.
DETAILS OF OUTLETS OF ARJUN NAGAR ZONE
As on 15.10.2007
S.No. Particulars Outlet No.1 Outlet No.2
24 Hrs Suppty Daily 3.00 Hr Supply
1 Diameter of pipe
Physical and financial
Introduction
Amaravati water supply from Upper Wardha Dam as a source is in operation successfully since March 1994. As per audit report 1998-99 it was a finding that there was a hydraulic loss of 56% in the system, as a whole. At that time 6 no. of ESRs were under construction and not in operation. One by one these ESRs were put into operation. 56% losses in the overall system refer to the period before additional 5 ESRs were put into in operation. Every ESR has its own distribution system, which might have been additionally laid or contributed from the existing distribution system. This distribution system was to be laid for the equitable water supply to the city. During the process of phase of execution, continued efforts were being done to restrict the losses to the bear minimum. These efforts should go on continuously. Reported losses in 2003-04 are 21.82%, indicating substantial reduction by 34%.
Influence zones
Concept of influence zone of ESR has not been tried elsewhere on field. No reports are available of having efficient distribution by adding the no. of ESRs in the existing network. Amaravati has initially only Maltekadi as GSRs in two zones, working in the radious of 14 kms. After some years 4 new ESRs were put into operation. Apart from their storage capacity, their elevation decided the influence zone. In those days (1987-89) Whole City was dependent on ground water as a source. There was water shortage. Approximately, 65 LPCD water was distributed. System had much higher capacity.
From Maltekadi, when the water was let out to the system, system volume being much higher there was quick drop of level in the storage and also the system pressures. Improvement was seen, due to zonal ESRs, (VMV 15 lakh lit.,Nagpuri gate 20 lakh lit.). They were constructed at the rear end of the Maletekadi influence zone and tried to be fed from REOSA tube well water by laying separate rising mains. Overall quantity of water reaching to the City was the same and still the effect was seen positive in terms of increase of system pressures at the influence zones of new ESRs.
Subsequently, in the new sanctioned estimate for the Distribution system, additional 6 no. of ESRs were proposed to be constructed. 7 ESRs/GSRs were already existing. All these ESRs are at the periphery of the city. Total storage capacity of these ESRs is 120 lakhs.
Old Maltekadi 50 lakhs
50 lakhs
Badnera 12 lakhs
VMV, Nagpuri gate,
Bhimtekadi, Saturna 75 lakhs
Arjunnagar, Paradise colony
Mayanagar, Badnera New 80 lakhs
Wadali, Wadarpura 20 lakhs
Tapovan MBR 33 lakhs
Tapovan hsr 20 lakhs
Total 340 lakhs
For effective distribution Tapovan storages very near to the treatment plant are to be deducted. Available storage is (340-33-20) 287 lakh lit.
ESR duty
Population as per 2001 Census is 549500 souls. Prospective populations after 15 years will be approximately 860000 souls. Consumptive demand will be 120 ml/day. With losses at 15 % it will be 138 ml/day. For this purpose average ESR duty will be 1380/287 = 4.80. This figure is more than the design value. Hence, it is required to increase the storage to 460 lakh lit. This means that additional (460-287)173 lakh lit storage has to be increased in a phased manner. Or use of Tapovan GSRs can be made for direct distribution system. Irrespective of capacity of ESR, if the longer lengths are to be fed to the distribution system, losses in reaching the consumers will substantially reduce the pressures. This will give rise to the unsatisfactory service levels. This can be reflected financially also.
ESR duty up to 2.8 to 3 can be achieved by adding the additional outlets to the existing and newly constructed ESRs. Further, influence zone of ESRs shall be limited to encircled area of having a radius of 1.8 km.
Marking these influence zones on the distribution map, will reveal the location of new ESRs.
ESR capacity
ESR duty round about 3 in the ultimate stage, means that 3 fillings of ESR. For 20 lakhs capacity it is 60 lakhs lit. Assume, it corresponds to 50000 souls of population. In the zone of influnce,1.8 km is assumed as radius. For safety factor there should be 15% envelope area of adjoining zones. Area of influence zone comes to 1017 ha. Assuming 15 % envelope area this reduces to approximately 865 ha. If 50000 souls are getting accommodated in the influence zone, then the population density comes to about 55 persons per ha. This fairly matches with horizontally developing city areas of Vidarbha. Regarding capacity of ESR, it can be decided as following. Demand comes to 50000 * 120 =60 lakh lit. Ideal losses at 15 % in the distribution system can be added. Hence, demand comes to 72 lakh lit with 20 hr working and 3 as duty, appropriate ESR capacity comes to 25 lakhs. If the hector density is more the storage capacity shall change.
All these principles have not been tested in any city. Amaravati distrbution is developing since 1960.upto now more than 650 km of pipelines are laid in the town during various time periods.
Regulatory measures
Till the above factors do not tally, the losses will be maximum compared to the consumption. The revenue losses are based on the realized revenue. Billed quantity is identifiable in case of working meters. However, in the system % of working meters is always less. In case of Amaravati City working meter % is about 70%. In such cases billing is based on average consumption, minimum consumption or any amicable derivation not related to the actual supplied quantity of water. Hence, whatever is assessment; it is converted into hydraulic quantity. This is possible with the help of computerized data of consumer connections. This is rarely available in other cities. It has become unique feature of Amaravati water supply, as this data is available in Amaravati for last 15 years. Inadvertently, field staff supplied quantity of water, without any logical control. Naturally, supplied quantity was much more in comparison with the billed quantity. Meter reading staff was also not guided for the frequent checks that they are required to observe. Initially it was a task to discuss with the field and meter reading staff and tell them the logic to minimize the system losses.
First reaction is always negative and they may not understand the importance of control measures. Supplied water is a valuable commodity and it has to be distributed for the fruitful use and not for waste. Wastage of water is a financial loss. The water available is not unlimited. It should be supplied on some calculations and it has to be checked whether these calculations are correct to realize the revenue. Field staff was asked for controlling the incoming quantity of water to ESRs. It was against the normal trend and offered intrinsic resistance from the staff. But the views were to be canvassed frequently. It took about 4 to 5 years to come to an asymptotic behavior of the demand. Once this end has been seen to be approaching, system theoretically should run in the profit. Staff did co-operate further, as they could realize that they have contributed to the profit, by adopting more scientific view in the water supply management. For such quantity audit, a high profile proposal would have prepared by any external consultant, leaving the all-soft part to the staff and administration. Still the results would not have been so encouraging as in Amaravati. Another indicator is population to connection ratio. It should approach to 10. If it is maintained at that level, profits are assured. When it reaches to less than 7 it will completely refund loan.
Computerized billing process
Computerization of the billing process has been the plus point of the Amaravati water supply scheme. The software is most user friendly and has become intelligent, during continuous use, since last 12 years. In last 12 years it has faced, all receipt and expenditure audit. It has produced all sorts of accounts and information to the audit. It is capable of analyzing the performance of meter readers in their beats, since 1997. Various meetings were held of all concerned meter readers, counter clerks, fitters, section officers, to evaluate their performance with the help of computer data. They were guided to perform better. Targets were given and seen whether they have been achieved. With the computerization, there was better control over the billing cycle of all 55000consumers. For maximization of the revenue, the assessment should be raised.. Billing should be for all 6 bi-months in the year. Revenue from higher size connections were particularly watched in the meetings.
To make best use of the computerization already existing, following things are required,
* Prepare maps of the ESR zones. Give line Identification no. Branches may also be shown and be numbered.
* Consumer number may be modified based on the above data. It may be alphanumeric. such as " sa bc24 5 045678 "
* It reflects for Saturna ESR, line - bc, 24th branch, 5th connection.
* This unique number has to be entered in the bill process. immediately.
* Assign these numbers to the consumers.
* At any time location of the consumer is traced.
* Total number of bills in the ESR zone will be known to anybody
Exact demand on the zone can be estimated accurately.
* Control over the meter-readers will be increased.
* After allotting these numbers all other information can be fed to the computer by creating some additional fields to the database.
* Featural analysis can be available any time from the computers.
* Technical decision has to be guided through computer.
Energy saving
By keeping power factor at 0.99, a rebate can be availed from MSEB. For that purpose peak hour pumping is being avoided. This is rational. It is leading to energy saving and also economical. The efforts taken by mechanical wing are worth appreciating.
Regarding indirect saving in the water quantity not pumped to the city, is also energy saving criteria. But it is more conspicuous when the extra quantity, which otherwise would have been wasted, is conserved as a useful storage in the reservoir itself. Wasted water has production value of pure water. This whole water, if sold to the consumers, would have fetched lakhs of rupees. It has traveled to the doorsteps of the consumers but not billed, and as such unaccounted. Following table will give the idea of indirect saving.
Hence, it was a good step to come close to the actual water consumption of the consumers. Since 1999-00 to this date the efforts are on, to reduce the pumping from Simbhora. Even though, the water demand was increasing, day by day, population has been increasing and the connections are also increasing. Thereby the demand for water was also increasing. In the year 2002-03 more than 3000 connections were increased, Still, there is constant reduction in pumping, indicating the increasing efficiency of the system and that of the staff. It indicates that indirect saving would have been much more. Nobody can work in isolation to give the system efficiency improved. It is conscious, combined, elaborate and unidirected efforts put into to achieve the targets with full understanding. For canvassing this hourly levels and day to day supply, record has been generated and displayed the results in various meetings with the staff, so as to make them appraised of the fact that, things are going on the right track.
Effective control on the incoming water quantity has not affected the revenue; instead it has increased, year by year. Seeing the actual figures, contribution from staff was increased. A statement for supply on each day during years from 98 –99 to 2003-04 will give an idea of as to how the supply was matched with actual demand and ultimately effected in indirect saving. Total saving in ml/year and cost of water saved indirectly per year shown separately.
Financial status
Amaravati water supply scheme has been handed over for maintenance by Amaravati Municipal Corporation on 9-8-1983. Since then scheme has been under control of Maharashtra Jeevan Pradhikaran from source to consumer. At the time of handing over there were only 14000 connections out of which about 4000 connections were un-metered and in addition there were about 1000 standposts in the city. Scheme was running in loss. Expenditure on salary was much more. It was dependent on Pedhi, Purna river sources and the reliability of these sources had come down drastically. Moreover, 110 workers borne on the scheme were brought on CRT and sent to MJP along with the scheme. Old sources, Chatri Talao and Wadali Talao were handed over to MJP for M&R.
.
Systematic efforts were put in to reduce the expenses and to increase the revenue. For this purpose complete analysis of the distribution system was done based on the computer data. Demands from each area were analyzed and its trends were studied. Augmentation as well as improvement schemes were executed during this process. Augmentation scheme was complete by March 1994. Improvement to distribution was complete by 2001. Water was available from Upper Wardha Dam. Source was not a problem. Rational distribution was still a problem. To asses the new level of service, 100% house to house consumer survey was done and analyzed. Demands were reworked out and related to supply side for broader control at Old and New ESR points.
Statement of assessment, revenue and expenditure year wise will clarify the financial status. It can be seen that profit has not accrued till 2001-02 as compared to revenue. But since then, profit is the trend. Technological improvement has more concern to the profit in comparison to cutting expenditure by audit. Technology, sincerely applied goes long way. While rationalizing the supply it was aimed not to bring down the revenue. These efforts took four to five years to give the required results. As it was a soft part to train the meter readers, fitters, valvemen, supervisors and finally engineers. Consumers were also increasing in number and the demands also were increasing but still they were involved in the process by educating the meaning of the bylaws and rules for the billing process. For this purpose years computerization of the billing process helped to sort out the grievances of the consumers and redressels in the various forums. In last 25 years of management assessment, realization figures are increased 25 times, with profit peeing in after 20 years.
It can be revealed that to reduce the expenditure it is required to concentrate on energy cost. Separate attention was given to study the measures to reduce the expenditure. Major concentration was to reduce the pumping head so as to increase the discharge keeping the pumps as installed originally in the year 1993.Discharge was really increased.
With the adaptation of two measures there is a reduction in the head to the minimum of 20 m and the discharge was increased by about 35000 lit per hour for single pump application. System is always run for 24 hours. Naturally it was possible to plan for pumping at night hours more to get the benefit of subsidized rate per unit consumption.
Institutional efficiency
It is required to compile the hour to hour levels recorded for the various ESRs in the city. Total day's supply is also compiled. Comparison of the days supply with the supply made to the city in the earlier year. This comparison can be made for 4 years before. It can be seen that attempts are continuous to get the control over the supply year by year. Till the time when the supply remains constant or at par with the previous years’ supply, there is always a scope to improve. Results can be seen. Deciding the influence zones of the ESRs in the city, it was possible to identify the population served on the particular ESR. The demand and duty assigned to the ESR can be ascertained. For all the section officers the task was given to control the outgoing from ESR to be matching with demand from the relevant population. For want of better instrumentation, this was done from the previous data, and application was done manually. It took lot of time to stabilize the demands and duties of all the ESRs in the city. When the system was stabilized confidence level of the field staff was increased. Reporting and control management was improved. During the periodical meetings this exercise was discussed with field staff and they were shown the results in the saving in quantity of water. They were encouraged to suggest their own methods for further improvement. They were assessed and upheld. Due recognition was given to the field staff in the various functions for their good contribution in the process. From valve operator to section officer, all were “level conscious” as far the ESRs is concerned.
Before this indicator was in force there was no control over the water supply to the city. Day by day the demand is increasing and still the supply is getting reduced, is indicator to reduce the hydraulic losses.
Assessment increase measures
Increase in the assessment is mainly due to finding out the unauthorized stand post connections taken by Municipal Corporation. Corporation normally denies that they have taken the connections but still they exist. They are not on the record. Hence, it is not billed. Thereby it is a loss of revenue. Corporation may suggest that Pradhikaran can disconnect the connection. But, it is the user authority who is required to take the action, by giving notice to the local people surrounding the stand post area. Pradhikaran may take action after corporation has taken necessary steps. When unauthorized stand posts are taken on record the revenue will go on increasing. The bills are given with retrospective effect. These arrears are to be included in the basic records of corporation.
It is in the interest of the corporation to disconnect the stand posts, which are very less used but being charged at the constant rate by Pradhikaran. Disconnection shall be with the alternative that all nearby users can have the house connections given by the Pradhikaran. in that case the bills are being paid by the users and not by the Corporation. Hence, the Corporation, as well as, Pradhikaran is benefited. Statement of disconnected stand posts and recording unauthorized stand posts is enclosed and how the assessment has effected.
Professionals, doctors, etc., have been identified to be applied with non-domestic rates. House to house survey had been conducted. This survey had been conducted, by the staff of Pradhikaran. Irregular connections have been identified. In the survey level of service was recorded. In some cases 24 hour water was identified and in some cases, one hour supply was seen. For having equitable distribution necessary planning has been made. Irregular connections have been tried to be regularized. With all this, assessment has been increased substantially. Statement for such efforts is enclosed.
Efficiency increase tools
"Who pays" analysis from the computer has been very interesting. It was observed that normal regular payers are from the low income groups. In case of higher size connections, either the meters were out of order or the meters were not in position. Bills are found to be going on lower averages which recorded long back when the supplies were inadequate. This analysis also gives the inefficient meter readers, who were slack in delivering the bills. It results into less revenue. A sample statement is enclosed herewith.
Monthly receipts are tallied with the cash book figures. With 50000 connections of the scheme support from the computers is a must. This gives a cross check. Receipts are mainly through co-op. Bank. Similarly, assessment is given meter-reader wise. Computer gives an abstract of the status of the meters. The area in which nonworking meters are functioning, it has to be watched closely. It is very likely that consumers are happy with paying, at the flat rates, that is indicating higher supply area and more wastage. Line valves are required to be adjusted. A sample can be given to illustrate this point.
Cross checking by the totally different staff by directly contacting the consumers and asking their reactions, keeps a better control over the meter-readers. Changing areas or beats of the meter readers also becomes effective but there is a large proportion of resistance from the staff.
External contribution
Pradhikaran has allowed using the services of Co-op. bank for collection of revenue. It has five branches in the city. For 50000 consumers and 6 bills per consumer, in a year, maximum charges are Rs.300000/- per year. For computerization of bills it is rs.720000/- per year. Hence, total services taken externally are required to be paid up to Rs. 1020000/- per year. Expenditure on both these items is revenue expenditure. In terms of percentage it is hardly 1% of the revenue. Lot of thinking man days have been put into. It has not emerged into software as readymade. It is a customized software. Over a period it has become most utilizable and the intelligent software. Our staff means the same staff from the subdivision who is involved in the billing process. It is always better that the third agency is involved in the process so that there is always a countercheck on the happenings on the billing process. These counterchecks have been introduced in the software. The officer concerned, should make use of capabilities of software. There are other software in the field, but to get the equivalent transparency they need a long voyage. This software has been tested by every receipt audit. It has given all records. Software which was previously only used for billing is working at the same rates for receipts also. Naturally, it has the capability for developing the consumer wise, area wise, beat wise, month wise, abstracts and can create annual reports. Manually it is possible but considering the huge number of connections, it is always lagging. Vertical totals are sparingly correct. It is understood that these accounts should be kept manually. But it should be appreciated that earned revenue of crores of Rs. is entitled to have the computer cross check. Expenditure on the ledger creation will be only Rs.40,000/-. It is just .04% of the revenue. It will update everything. It will support the working of staff. All staff are not equal. Any fraudulent tendency can be curbed through cross check. For last such incidences, computer had come to the help and used by office to crystallize the extent of such activity. It had been the practice to tally the monthly receipt account with the cash book. Audit may think of keeping the process online. Install computers in the Subdivision, Division. It may cost something, but it is relevant to push the things ahead.
Internal economy
Over a period number of consumers has been increased substantially. For 56000 consumers and bimonthly billing 25 meter readers are required. But without appointing any external persons the job has been carried out by drafting equivalent trade wokers as meter readers. These were working as counter clerks, karkoons etc. they were released from their assignment as receipts were given to co-op. Bank. Extra expenditure was saved. It has the capacity to handle even more increase in the consumers. New tender now includes the condition that agency can further update the software into oracle, if required, to handle still better. Expenditure on establishment is given year wise and the trend may be noted.
It has started with the issue of system losses. They had compared the incoming water quantity to the billed quantity. This quantity was by computer by calculating reverse from the rate at which they were billed. Hydraulic quantity was compared with quantity derived from financial bills. Basically, these two are separate entities. Still, this was taken as a task. It took 3 years to get some positive results but now the trend is set. Following table will clarify the point.
Year Pumped Supplied % loss Remarks
1997-98 20.04 mcum 11.70 mcum 41.62 % loss
1998-99 22.00 mcum 11.70 mcum 46.82 % loss
1999-00 20.94 mcum 11.47 mcum 45.22 % loss
2000-01 23.37 mcum 10.28 mcum 56.01 % loss Maximum
2001-02 21.33 mcum 14.53 mcum 32.04 % loss Reduction 23.97 %
2002-03 21.28 mcum 16.18 mcum 23.97 % loss Reduction 32.04 %
2003-04 16.43 mcum 12.95 mcum 21.82 % loss Reduction34.19 %
Whole exercise was to improve the efficiency of the system. It has elaborated the answer for the improvement gateway. The lead has been taken to find out the root cause with the help of same available staff and guided them to go ahead on positive way, which is techno economical and professional too. Adding some more ESRs in the system has rationalized the system supply and has contributed in reducing the losses.
Immediate plans
Four new ESRs have been proposed and they are under construction with some addition of distribution system. Effect of which can be seen in coming two years. Methods have been logically imparted to all the field staff and that is the main success of the exercise.
24X7
When the losses have been controlled, it is a good base to take up the 24x7 water supply. It is not possible to apply to whole of the city as in old areas stand post supply still prevails. In this area 24x7 supply means the increase in the wastage. Hence, selection of new area has been done. In Arjunnagar area water supply is mainly on connections. In this area also trial is being taken on one outlet at the first instance. The details of the area are given below in the table.
DETAILS OF OUTLETS OF ARJUN NAGAR ZONE
As on 15.10.2007
S.No. Particulars Outlet No.1 Outlet No.2
24 Hrs Suppty Daily 3.00 Hr Supply
1 Diameter of pipe
350 mm 250 mm
2 Supply Hours
2 Supply Hours
24 Hrs. 7.30 to 9.45
3 Area covered
3 Area covered
Vinayak Nagar
Shegaon Gaothan MSEB ,
Arjun Nagar Coloney
Shrihari Nagar
Shriram Nagar
Rahatgaon
Sonal Coloney
4 Total Population 12879 9353
5Population served 8100 6150
6No. of Connections ( Exisiting ) 632 950
7Proposed new Connections 795 624
8Daily Requirement at 135 LPCD 1738665 1262655
9Present water supply in Ltrs. 950000 760000
( Actual supplied Qty )
10Actual Assessed Quantity 817500 610000
11Per capita Supply 117 124
12Loss of Water - % 13.94% 19.73%
13Peak Factor 3 4.5
14Total Length of Pipeline 9.51 Km 7.20 Km
15Proposed Pipelines6.20 Km5.40 Km
16Assessment per Year 28.08 Lakh 22.65 Lakhs
17Annual Recovery 23.75 Lakhs 17.32 Lakhs
18% of Recovery 84.60% 76.50%
19Per connection paid bill Average Rs. per Annum.
3758 1823
Water supply control has two fold effects. Apart from the reduction of losses main aim is to get more revenue. Use of water in case of 24x7 is expected to increase. It is always seen initially. However, if the billing efficiency is good then the revenue is comparatively increased. Per connection average payment per annum will be increased. For purpose of comparison the supply on the second outlet is available. The data is noted for the second outlet and it can be found out that first outlet has supplied less per capita supply in comparison with the second outlet and further it is to note that losses are less in this 24x7system. Thus 24x7 supply is no doubt effective and it is encouraging to improve the system by extending the concept of 24x7 water supply to larger area. On one side it educates the people to use less water as they shall have to pay for it and at the same time it has the facility to use water as and when required. It builds up confidence in the minds of the users.
STATUS OF WATER METERS OF ARJUN NAGAR ZONE - OUTLET NO.1 ( 24 X 7 )
As On 15.10.2007
Sr. No. Status Diameter Total % 100
15 mm N/D D N/D D
1Meters Working 103 605 609 99.19%
2Meters Non Working 000 18 18 2.93%
3Disconnection 1 4 5 0.81%
The status of the working meters in the outlet no. 1 area shows positive trend about the working meters. All consumers have meters and about 99% are working. This is a good sign of efficient management.
.
Shrihari Nagar
Shriram Nagar
Rahatgaon
Sonal Coloney
4 Total Population 12879 9353
5Population served 8100 6150
6No. of Connections ( Exisiting ) 632 950
7Proposed new Connections 795 624
8Daily Requirement at 135 LPCD 1738665 1262655
9Present water supply in Ltrs. 950000 760000
( Actual supplied Qty )
10Actual Assessed Quantity 817500 610000
11Per capita Supply 117 124
12Loss of Water - % 13.94% 19.73%
13Peak Factor 3 4.5
14Total Length of Pipeline 9.51 Km 7.20 Km
15Proposed Pipelines6.20 Km5.40 Km
16Assessment per Year 28.08 Lakh 22.65 Lakhs
17Annual Recovery 23.75 Lakhs 17.32 Lakhs
18% of Recovery 84.60% 76.50%
19Per connection paid bill Average Rs. per Annum.
3758 1823
Water supply control has two fold effects. Apart from the reduction of losses main aim is to get more revenue. Use of water in case of 24x7 is expected to increase. It is always seen initially. However, if the billing efficiency is good then the revenue is comparatively increased. Per connection average payment per annum will be increased. For purpose of comparison the supply on the second outlet is available. The data is noted for the second outlet and it can be found out that first outlet has supplied less per capita supply in comparison with the second outlet and further it is to note that losses are less in this 24x7system. Thus 24x7 supply is no doubt effective and it is encouraging to improve the system by extending the concept of 24x7 water supply to larger area. On one side it educates the people to use less water as they shall have to pay for it and at the same time it has the facility to use water as and when required. It builds up confidence in the minds of the users.
STATUS OF WATER METERS OF ARJUN NAGAR ZONE - OUTLET NO.1 ( 24 X 7 )
As On 15.10.2007
Sr. No. Status Diameter Total % 100
15 mm N/D D N/D D
1Meters Working 103 605 609 99.19%
2Meters Non Working 000 18 18 2.93%
3Disconnection 1 4 5 0.81%
The status of the working meters in the outlet no. 1 area shows positive trend about the working meters. All consumers have meters and about 99% are working. This is a good sign of efficient management.
.
Subscribe to: Post Comments (Atom)
Subscribe to:
Posts (Atom)
