STUDYING EXISTING STATUS AND GENRATING APPROACH TO OPTIMISE OUTPUT FROM 225 MLD TREAMENT PLANT AT AGRA CITY

Introduction

Agra city is an important city in Uttar Pradesh and is having a population over 16 lakhs souls. City is on the Banks of Yamuna river and has historical importance. World famous TAJMAHAL is in the City. For Drinking water city is dependent on Yamuna river. From the British period a treatment plant is existing in the city. During last 4 decades the plant capacity has been increased as per requirements and a new treatment plant also has been constructed u/s of the existing treatment plant. City's demand for water is consistently increasing. Planning for augmentation is in view with appropriate alternatives; however, the existing facility is also being studied for better output and renovation and up gradation.

In this connection the plant was visited during 23 June to 26 June 2009 along with Shri. Kalelkar and Mr. Mustafa to gather observations and the compilation of views to arrive at the areas in which some additions and alterations are needed to give better utilization of the facility to give desired output. It was learnt that similar pilot report has been submitted by M/s. Water Services Ltd. This report was also referred.

Inception

Initially treated water sample which was authentically tested by the AES Lab, Delhi, was checked so as to know about the type of output of water from the Treatment plant, known as WW 1.

Treated water sample analysis by AES Lab, Delhi, is reproduced here for considering major parameters.

Parameter	Results	units	Desirable limits	Comments
Color	<1		% max.
Odor	UOB
Taste	Agreeable
Turbidity	<1	NTU	5 max.
pH	6.81		6.5—8.5	Within range
Total Hardness	124	ppm	300 max.
Chlorides	81	ppm	250 max.
Iron	0.291	ppm	.3 max.
Re. Free Chlorine	0.2	ppm	0.2
Fluorides	.49	ppm	1 max.
TDS	493	ppm	500 max.	Marginal
Mn	0.336	ppm	0.3 max.	Marginal excess
NO3	3.79	ppm	45 max.
Total Alkalinity	65	ppm	200 max.
Coliform	Absent	Per 100 ML	0 max.

 

This sample was sent by Waterchem Services, as per their pilot treatment suggested by them.

It was found that the Mn which was found excess than the limits was due to Alum which was being used in the existing process of treatment. When the Alum quality was changed Mn was brought down or nullified and it was confirmed during the subsequent testing. All other parameters were within limits.

Waterchem services found few samples in which Coliforms were detected. These samples were of pure water distributed to the consumers. Waterchem services has suggested Aeration by adding chemicals and pH adjusters in the treatment process.

 

 

Test Results : Samples collected under group A

Sr. No.	Sample No.	Turbidity	Odor	Ammonia	Bacteria Coliform	Bacteria E-coli	Res. Chlorine
1	4	10	OB	3.0	17	A	0.2
2	5	10	OB	3.0	A	A	0.3
3	6	12	OB	3.0	A	A	0.3
4	7	8	OB	3.0	A	A	0.3
5	8	6	OB	3.0	A	A	0.2
6	9	8	OB	3.0	A	A	0.3
7	10	10	OB	3.0	26	A	0.2

 

 

Test Results : Samples collected under group B

Sr. No.	Sample No.	Turbidity	Odor	Ammonia	Bacteria Coliform	Bacteria E-coli	Res. Chlorine
1	1	8	OB	3.0	A	A	0.4
2	2	8	OB	3.0	A	A	0.3
3	3	7	OB	3.0	A	A	0.4
4	4	8	OB	3.0	A	A	0.4
5	5	8	OB	3.0	14	A	0.1
6	6	6	OB	3.0	A	A	0.4
7	7	6	OB	3.0	17	A	0.2

 

 

 

 

 

Test Results : Samples collected under group C

Sr. No.	Sample No.	Turbidity	Odor	Ammonia	Bacteria Coliform	Bacteria E-coli	Res. Chlorine
1	1	9	OB	3.0	A	A	0.5
2	2	7	OB	2-3	12	A	Nil
3	3	8	OB	3.0	A	A	Nil
4	4	7	OB	<3	A	A	0.4
5	5	7	OB	<3	A	A	0.3
8	8	5	OB	3.0	A	A	0.2
9	9	6	OB	3.0	A	A	0.3

 

 

Test Results : Samples collected under group D

Sr. No.	Sample No.	Turbidity	Odor	Ammonia	Bacteria Coliform	Bacteria E-coli	Res. Chlorine
1	1	8	OB	3.0	A	A	0.3
2	2	8	OB	3.0	12	A	0.3
3	3	7	OB	3.0	A	A	0.4
4	4	6	OB	3.0	A	A	0.3
5	5	6	OB	3.0	A	A	0.3
6	6	10	OB	4.0	A	A	0.4
7	7	9	OB	4.0	A	A	0.3

 

 

The city was divided into four zone. A,B,C,D. Samples were taken from the distribution system in these zones. Some of the samples are shown above from each zone. In all the samples it can be seen that there is odor problem and ammonia is found in all of them. Ammonia is 3 or more in all the samples. Incidentally, it is seen that in all the samples residual chlorine is available. Turbidity is just more than the limit of 5 ppm. In few samples coliforms are found. Odor and Ammonia, and coliform are major problems. All of them have roots in the raw water quality.

 

 

 

 

 

 

Raw water quality

Water quality of Yamuna river is consistently getting affected downstream of Delhi. It is monitored by Delhi Pollution control committee and results are available at various locations near Delhi. From Pala to Agra Canal at Jaitpur the quality of water is going down.

pH varies from 8 to 7.6

TSS has increased from 32 to 114 ppm

COD has ranged from 12 to 132 ppm

BOD has ranged from 2 to 28 ppm

DO has depleted from 9 to zero just near to downstream of Najafgarh drain

Total Coliform has increased from 5000 to 1200000 MPN/100 ML

Delhi is the first major town on the banks of Yamuna river. Waste water from Delhi Metro is let into Yamuna river either after treatment or in some cases without any treatment. Some industrial effluent is also let into the river. Pala is just upstream of Delhi and the quality at Pala is much better than the downstream locations. It is getting worsened as one moves down the stream. Normal restoring capacity of the river in terms of quality falls short for the inflow of pollutants. From Delhi onwards, Faridabad, Mathura all contribute in polluting the river. Downstream of Najafgarh Dissolved oxygen is zero and it shows that all dissolved oxygen has been depleted and the biological oxygen demand is increasing. To that extent it can be seen that river does not get a stretch downstream to get restored naturally nor does it get a chance of dilution by having an influx of another fresh stream.

Coliforms No. in the stream is increasing downstream of Delhi. Consistently the number is increasing. Freshness of water in the river is disappearing. Lot of efforts are being done to control for years together, but the effects are yet to be seen. For the town and inhabitations downstream this is the natural source available for the drinking water. But as a source this has limitations and methods of treatment has to be to counter the pollution. Most familiar disinfectant is chlorine gas and it is used on large scale for pre-chlorination in the source. These local efforts can not change the total quality of water in the river.

Record has been kept of sample testing of the river at various points along the stretch of the river, particularly Delhi and below. This information is available on the internet. Yearly average of the quality parameters at various places are picked up and given below,

 

 

 

 

Sr. No.	Sampling Location	pH	DO	BOD	COD	F_Coliform in MPN/100ml
	Tajewala Hathnikund	7.84	10.2	1.25	6.25	6262
	Kalanaur	7.90	8.95	1	6	30550
	Sonepat	7.85	7.32	1.75	13.5	329750
	Pala	7.84	8.53	1.75	14	31600
	Nizaamuddin Bridge 1/4	7.25	0.9	23.5	73.75	15555000
	Nizamuddinn Bridge 1/2	7.30		25.33	78.66	15533333
	Mathura U/S	7.91	6.48	8	72	111000
	Mathura D/S 1/4	7.80	8.29	10	45.5	523000
	Mathura D/S 1/2	7.96	7.08	10	51.5	371750
	Agra Canal 1/4	7.44		17.5	60.5	10845000
	Agra Canal 1/2	7.48		17.33	63.33	9213333
	Agra U/S	8.31	10.08	8	48.66	477600
	Agra D/S 1/4	7.87	6.50	25.25	95.75	10150500
	Agra D/S 1/2	7.67	2.15	31.75	120.75	12222500

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The autotrophic conversion of ammonia to nitrites and nitrates requires oxygen, and so the discharge of ammonia nitrogen and its subsequent oxidation can seriously reduce the dissolved oxygen levels in the rivers, especially where long residence times required for the growth of the slow growing nitrifying bacteria are available. Also, these organisms are produced in large numbers by highly efficient aerobic biological waste treatment systems, and their discharge with the treated effluent can cause rapid nitrification to occur in waterways. Disinfection of effluents with chlorine can minimize this problem.

 

 

 

 

 

Nitrogen control has become an important consideration in the design. Limitations have been imposed because of suspected toxic effects upon fish life. It is well known that molecular ammonia is toxic but that the ammonium ion is not. Since the relationship between the two is pH dependent.

NH₃ + H⁺ NH₄⁺

It shows relationship between free ammonia and ammonium ion that exists for several concentrations of ammonia nitrogen over the pH range of interest in natural waters. Free ammonia concentrations above 0.2 ppm are problematic to fish. Hence permitted concentrations are reduced. Ammonia toxicity will not be a problem in receiving waters with pH below 8 and ammonia concentrations are below 1ppm. Control of ammonia for the above reasons can be accomplished by actual removal of ammonia
or by nitrification. The amount of ammonia nitrogen present in water determines to great extent the chlorine needed to obtain free chlorine residuals in breakpoint chlorination and determines ratio of mono-chloramines to di-chloramines when combined chlorine when combined chlorine residuals are involved.

Organic Nitrogen

NH3 N

NO3 N

NO2 N

3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 Days

 

 

 

Nitrogen is originally present in the form of organic nitrogen and ammonia. As the time progresses, organic nitrogen is gradually converted into ammonia nitrogen, and later on, if aerobic conditions are present oxidation of ammonia to nitrites and nitrates occur. Waters with most of the nitrogen is in the form of nitrates it can be considered that the pollution was there, but it was much long ago. Waters with existence nitrite nitrogen is questionable and bacteriological test for coliform provides evidence regarding hygienic safety of waters.

The Nitrate electrode is a liquid membrane electrode. It can detect the presence of Nitrates down up to 1 ppm. For continuous monitoring it is convenient.

 

 

Chlorine combines with water to form hypo-chlorous and hydrochloric acids.

Cl₂ + H₂O = HOCl + Cl ^–

(H⁺)(Cl^-) (HOCl) (4* 10 ^-4)

(Cl₂)

 

Heavy chlorination is being done at source. It is observed that even from the distance of 150 m the chlorine smell was cognizable. Hence, the mixing after dosing is not being done or chlorination can be done with better distribution.

	500	ppm
100
25 ppm

0 100     

20 80

40 % HOCl 60 % Cl₂

60 40

80 20

100 0

pH 1 2 3 4

 

 

 

 

Chlorine reactions with Ammonia

Ammonium ion exists in equilibrium with Ammonia and Hydrogen ion. Ammonia reacts with hypo-chlorous acid to form mono-chloramines, di-chloramines, and tri-chloramines depending upon the relative amount of each and to some extent upon pH as following,

NH₃ +HOCl = NH₂Cl + H₂O

NH₂Cl + HOCl = NHCl₂ + H₂O

NHCl₂ + HOCl = NCl₃ + H₂0

Mono-Chloramines and di-chloramines have significant disinfectant power and they are comparatively long standing. Two factors are important in disinfection: time of contact and concentration of disinfectant. Long contact time with low concentration or high concentration with lower time of contact has similar effect. Cholamines are called combined chlorine residuals. Greater concentration of combined chlorine residuals are required than free chlorine to accomplish a given kill in a specified time. The rate of reaction between Ammonia and hypo-chlorous acid varies upon pH and temperature. It is rapid at pH 8.3 and goes down for other variations in pH on either side.

 

Mole ratio Chlorine: Ammonia Nitrogen

8	0.5	1	1.5	2
7 Res. Chlorine
6	Cl2 Dose Applied
5
4
3
2			Break point
1				Free res. Chlorine

Cl₂ Dose

ppm 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

 

Ammonia nitrogen (N) is present in variable concentrations in many surface and ground water supplies. A product of microbiological activity, ammonia when found in natural water is regarded as indicative of sanitary pollution.

Ammonia is rapidly oxidized by certain bacteria, in natural water systems, to nitrite and nitrate--a process that requires the presence of dissolved oxygen. Ammonia, being a source of nitrogen is also a nutrient for algae and other forms of plant life and thus contribute to overloading of natural systems and cause pollution.

In fish, ammonia represents the end-product of protein metabolism and what is important is whether it is present in the un-ionized form as free ammonia, NH3, which is toxic to fish (both freshwater and marine) at >0.03 mg/L (ppm),
or in the ionized form, NH4+, in which it is innocuous. The relative concentration of each is pH and temperature dependent. The higher the pH, the more of the NH3 will be present. Ammonia can block oxygen transfer in the gills of fish, thereby causing immediate and long term gill damage. Fish suffering from ammonia poisoning will appear sluggish and come to the surface, as if gasping for air. In marine environments, the safe level of NH4+ is between 0.02 and 0.4.

The USEPA recommends a limit of 0.02 ppm as NH3 in freshwater or marine environments. Total ammonia levels, at this limit, can range from 160 ppm at pH 6 and temperature of 5 degrees C to 0.06 ppm at pH 9 and temperature of 25 degrees C.

If large quantities of fish are suddenly added to the water body (such as during stocking), the ammonia level can spike because the natural bacteria that degrade ammonia are slow to reproduce (having a 14 day cycle),

Nitrates occur in water as the end product in the biological breakdown of organic nitrogen, being produced through the oxidation of ammonia . Although not particularly toxic to fish, excess nitrates in the water is often used as an indicator of poor water quality. Under anaerobic conditions, such as in the sludge or soil at the bottom of a pond, lake or aquarium, denitrification can be used to convert nitrate back to nitrite and from there to nitrogen gas, removing total nitrogen from the aquatic system. In marine environments, levels of 0.1 to 0.2 are considered ideal.

Levels exceeding 50 mg/L (ppm) nitrate-nitrogen are considered unhealthy for lakes.

Levels from 10 mg/l to 40 mg/l indicate poor water in aquariums, depending on the species being raised.

Process alternatives

For removing above mentioned impurities alternative treatment processes are as below,

1. Conventional treatment process with Rapid sand gravity filters
   
2. Primary sedimentation with slow sand filters
   
3. Pretreatment with HRF, sedimentation and slow sand filters
   
4. Primary sedimentation, Slow sand filters with Granulated Activated Carbon sandwich
   
5. Pretreatment with Ozon, Sedimentation and Slow sand filters
   
6. Coagulant sedimentation, membrane filtration
   

Treatment experiment at Istambul

Elmali Reservoir is water source for Istambul city. It is suffering from high ammonia content due to discharges of untreated wastewater upstream. On pilot scale it has been recommended to apply BW membrane. Removal efficiency was anticipated to be 95%. Removal is said to be due to the enlargement of molecular size of ammonium complex compound. pH was increased due to ammonium ion in complex form. Estimated cost of the treatment was in the range of $0.95 to $1.05 per cum of treated water.

 

Comparison of relevant different treatment processes

Relevant to 225 MLD Plant

Sr. No.	Parameter	Convene. With RSF	PST With SSF	PST HRF/SSF	PST With SSF GAC	PST With Pre-Ozon. SSF	Coag.Settle Membrane
1	Land requirement	0.3 Ha/MLD	0.45 Ha/MLD	0.35 Ha/MLD	0.45 Ha/MLD	0.45 Ha/MLD	0.25 HA/MLD
2	Capital cost	12 Lakhs/MLD	10 Lakhs/MLD	8.5 Lakhs/MLD	13 Lakhs/MLD	13 Lakhs/MLD	14 Lakhs/MLD
3	Maintenance Cost/Annum	1.2 Lakhs/MLD	1.1 Lakhs/MLD	0.8 Lakhs/MLD	1.2 Lakhs/MLD	1.2 Lakhs/MLD	1.2 Lakhs/MLD
4	Removing SS	92%	95%	91%	95%	95%	98%
5	Removing Org.	90%	98%	97%	99%	97%	90%

 

Existing use of chemicals (Ref. Water services report) for 225 MLD Plant

Chemical	Dose ( in ppm)	Quantity in kg	Rate (Rs. per MT)	Amount in Rs.
Ferric Alum	50	11250	3450	38813
PAC	22	4950	7650	37868
Chlorine	50	11250	10900	122625
			Total	199306

 

 

This gives approximate cost of chemicals used on plant is Rs. 7.27 crores per annum.

 

Review of existing plant facilities:

Exiting plant has been developed in stages as per necessity. It is in fact a combination of three plants. Old British period plant having a capacity around 106 MLD has Hudson settling tank and SSF as the units. Out of which SSF is completely out of use. It is completely filled up with soil and it has been turned into ground. Its structural status is not known. Other two consecutive additions of plants of smaller capacities are not cognizable but are partially in use. But the subsequent additions are 20 MGD and 90 MLD are to be considered as useful additions. Extension of Hudson tank is also useful. But all of them are missing one unit of natural aeration. WW2 at Sikandara has this unit. In case of WW1 more emphasis has been given on pre-chlorination of source. A battery of chlorinators works continuously and add about 50 PPM Chlorine dose to the raw water in the river. In Sikandara source chlorination does not exist. Reason told was that at 55 km upstream Ganga canal water is added to the river. It mixes with Yamuna water and improves the quality of Yamuna water, may be as the dilution effect. WW1 is about 10 to 12 km down stream of Sikandara.

Why aeration is more suitable on this plant?

1. Source is having DO level as zero.
   
2. Ammonia is traced in the source as it is found in the distribution more than acceptable limits.
   
3. NO₃ is detected at 3.75 ppm.
   
4. pH about 7.5.
   
5. Coliforms in large No. are identified in source and heavy chlorination dose is applied.
   
6. Aeration will support chlorination.
   
7. Algal growth is observed.
   

Head works

There are three jack well and pump houses. Entry of water from Yamuna river is through a created unlined channel. Due to inadequate level in the river a temporary bandhara has been constructed to raise the water level. Level near jack well on the day of visit was 479 ft. (146.04 m)It is readable on scale marked on the wall of old jack well wall. Maximum water level is shown as 508 ft.(154.88 m) Floor level of Pump house of No. 1 is about 513 ft. (156.40 m). Old jack well and pump house is called as Pumping station No. 1 and year of construction may as old as 1889. The intake is provided with steel rakes or grill but the condition is much deteriorated, due to rusting. Pump system is positive suction type. Old pump house is about 100 ft away. Old pumps are centrifugal pumps and system is installed in 1889 in the British regime. Probable the older system was with Diesel Engine driven pumpset as one such set is still existing in the pump house. Total 5 leads of suction lines have been taken to the pump house. All these pipe lines are old ones and as they have been used as the suction lines any small holes in the pipe line has become the trouble spot for maintenance. All possible methods to arrest the air entry/water leakage have seen to be applied to these lines. However they get naturally protected to some extent when the river water level increases.

Jack well No. 2 seems to have been constructed in the year 1970. Floor level is slightly higher than the older one, 516 ft (157.32 m ). Three pumps have been installed in the pump house. Inlet is protected with a grill, but is rusted. There is another floor at discharge head level. System of girders and grill needs to be attended to. One pump has vibrations. Civil structure of floor , doors ,windows need renovation.

Jack well No. 3 reported to have been constructed in 1980. Civil structure is in better condition. Only doors windows need renovation. Floor level practically same as Pump house No. 2. Installation of pumps is having no vibrations. But it has been reported that motor needs repairs frequently. Size of the pump house is sufficient to house three pumps. All the pumps are vertical turbine pumps.

Raw water pumping

Pump house No. 1 : Total 5 No. of pumps have been installed.

2 No. of pumps are centrifugal pumps and 3 No. are vertical turbine pumps connected directly to suction pipe line from the Jack well. All are 75 Hp pumps. Duty point is 3300 gpm at 50 ft head. As the suction starts from the river water level, delivery point shall be about 480 + 50 = 530 ft. (161.58 m). Assuming losses of 5 ft in the system delivery level can be 525 ft. (160.06 m). Discharge capacity of each pump is 3300 gpm. Hence, maximum output from this system is as below,

Pump House No.1 : Pumps	Discharge in GPM	Discharge in Lit/hr	Head in ft	Head in m	HP	Maximum discharge in MLD
Centrifugal Pump 1	3300	898920	50	15.25	75	21.57
Centrifugal Pump 2	3300	898920	50	15.25	75	21.57
V.T. Pump 1	3300	898920	50	15.25	75	21.57
V.T. Pump 2	3300	898920	50	15.25	75	21.57
V.T. Pump 3	3300	898920	50	15.25	75	21.57
				Total	375	106.85

 

Whole system is very old. Delivery piping is in good condition. Because of 5 lead lines the system is bit complicated. Efficiency in summer is doubtful. Underground suction lines need frequent repairs. For reconditioning of the pump set problems the workshop is attached to the pump house. Machinery and equipment is available. Working skilled staff is also available. Actual output may be less for keeping the standby. However pumping is done maximum through the system. Somehow it is a feeling that they are keeping the system running being old and traditional. Delivery point is as per old design is to the Old Hudson Tank. If there is an alternative old system can be tried to be used to the minimum.

 

 

Pump House No. 2

Pumping from this pump house is through three V.T. Pumps installed. The capacities are as below,

 

Pump House No.2 : Pumps	Discharge in GPM	Discharge in Lit/hr	Head in ft	Head in m	HP	Maximum discharge in MLD
V.T. Pump 1	14000	3813600	75	22.86	250	91.53
V.T. Pump 2	9000	2451600	75	22.86	200	58.83
V.T. Pump 3	4500	1225800	75	22.86	125	29.41
				Total	575	179.77

 

 

Considering standby Maximum Discharge from this pump house is 150.36 MLD. Actual standby is one pump 14000 gpm or running two pumps of 9000 and 4500 gpm pumps. It was observed that two pumps of 14000 and 9000 gpm pumps were in operation during visit. And it was told that pumps do not stop and run continuously if the electricity is available. Thus for this combination of working there is no real standby. It needs to be created. 4500 gpm pump can be replaced by new 14000 gpm pump, by doing other minor modifications. Due to heavy chlorination in the source, pump impellers of existing pumps need to be replaced. One such assembly was lying outside and it was observed that the condition from inside was not better. The effect of chlorination on shaft was not possible to be verified. It should be checked. It may require to use better grade of SS be used for impellers at least.

Electrical panel board for motors and OCB panel were not in a good condition. It needs complete renovation. Soft start starters shall be provided. All gauges on the panel were not working. Motor temperature readings were not possible to be taken as the meters were not installed or not in position.

Electrical system needs to be completely replaced. Use of automation to pumping can be introduced so that it may not be limited to only the 'on and off' operation. Rated discharge figures have been shown in the table above but there is no measurement of the discharge and no instrumentation was seen. Hence, it could not be ascertained that how much discharge is actually passing through the lines. It is suggested that minimum instrumentation and automation shall be introduced. Pumping logbooks were not available in the pump house.

No visible leakage through piping was observed.

 

 

Pump House No. 3 :

Pumping from this pump house is through three V.T. Pumps installed. The capacities are as below,

 

Pump House No.2 : Pumps	Discharge in GPM	Discharge in Lit/hr	Head in ft	Head in m	HP	Maximum discharge in MLD
V.T. Pump 1	14000	3813600	75	22.86	250	91.53
V.T. Pump 2	14000	3813600	75	22.86	250	91.53
V.T. Pump 3	9000	2451600	75	22.86	200	58.83
				Total	700	241.89

 

 

Considering standby Maximum Discharge from this pump house is 183.06 MLD. Actual standby is one pump 14000 gpm or running two pumps of 14000 and 9000 gpm pumps. It was observed that two pumps of 14000 and 14000 gpm pumps were in operation during visit. And it was told that pumps do not stop and run continuously if the electricity is available. Thus for this combination of working there is no real standby. It needs to be created. 9000 gpm pump can be replaced by new 14000 gpm pump, by doing other minor modifications. Due to heavy chlorination in the source, pump impellers of existing pumps need to be replaced. The effect of chlorination on shaft was not possible to be verified. It should be checked. It may require to use better grade of SS be used for impellers at least.

Electrical panel board for motors and OCB panel were not in a good condition. It needs complete renovation. Soft start starters shall be provided. All gauges on the panel were not working. Motor temperature readings were not possible to be taken as the meters were not installed or not in position.

Electrical system needs to be completely replaced. Use of automation to pumping can be introduced so that it may not be limited to only the 'on and off' operation. Rated discharge figures have been shown in the table above but there is no measurement of the discharge and no instrumentation was seen. Hence, it could not be ascertained that how much discharge is actually passing through the lines. It is suggested that minimum instrumentation and automation shall be introduced. Pumping logbooks were not available in the pump house.

No visible leakage through piping was observed.

 

Overall capacity of lifting raw water

Though the pumping capacities have been developed time to time, total installed capacity and expected output from them needs to be summarized.

 

Pump House No.	Discharge in GPM	Discharge in Lit/hr	Head in ft	Head in m	HP	Maximum discharge in MLD
No. 1	16500	4494600	50	15.24	375	106.85
No. 2	27500	7491000	75	22.86	575	179.77
No. 3	37000	10078800	75	22.86	700	241.89
	81000	22064400		Total	1650	528.51

 

It can be seen from the table that the overall installed capacity is more than double when one considers that the expected output from the plant is 225 MLD. It is good asset but it needs more maintenance cost of keeping all of them in working condition. It is likely to limit the working hours. In any case output can be 225 MLD. Reported output is somewhere 165 MLD. However, no record of flows was available.

Working capacity of pumps in three pump houses

In every pump house there is a preferred standby as per installation practice. Keeping standby maximum discharge capacity in each pump house is tabulated below,

Pump House No.	Discharge in GPM	Discharge in Lit/hr	Head in ft	Head in m	HP	Maximum discharge in MLD
No. 1	9900	2696760	50	15.24	225	64.72
No. 2	23000	6265200	75	22.86	450	150.36
No. 3	28000	7627200	75	22.86	500	183.05
	60900	16589160		Total	1175	398.14

 

It can be seen that with keeping standby also the pumping capacity is 80% more than the expected output from the plant. Even then the output reported is much less that about 165 MLD. It raises two questions about working. First is regarding efficiency and second is regarding leakages. On the plant, leakage of large scale was not visible; hence it becomes the question of efficiency of pumping.

Old system as a whole pumping, Hudson settling tank, defunct SSF, Clear water reservoir (condition could not be seen), is open for doubts regarding efficiency, and partially for leakages. Old pipes are however, are of good quality and may be even better than comparatively recent installations. It is checked for capacity of installations without depending old system. And those results are tabulated below,

 

Working capacity of only pump house No. 2 and 3

Pump House No.	Discharge in GPM	Discharge in Lit/hr	Head in ft	Head in m	HP	Maximum discharge in MLD
No. 2	23000	6265200	75	22.86	450	150.36
No. 3	28000	7627200	75	22.86	500	183.05
	51000	13892400		Total	950	333.41

 

It can be seen that Keeping standby as installed, Pump house No. 1 and Pump house No.2 pumps have the capacity 33% more than the expected output from the plant i.e. 225 MLD. Hence, only this working capacity can be utilized to give better proportional output.

For this purpose however, conditions in the installations are to be renovated to work more reliably and efficiently. As mentioned above the impellers need to be changed and if required the shaft be checked. However, the process should start from checking the flows and recoding for reasonable time all salient discharge points.

Proposed Arrangement

9000 gpm pump to be taken out from Pump House No.3.

4500 gpm pump to be taken out from Pump house No.2.

Reinstall 9000 gpm Pump in place of 4500 gpm Pump in Pump House No.2.

Install New 14000 gpm pump in pump House No.3 in place of 9000 gpm pump taken out.

Combination after change

Pump House No.2	Pump House No.3
14000 gpm	14000 gpm
9000 gpm	14000 gpm
9000 gpm	14000 gpm

 

Proposed working of pumps and their minimum capacity

Pump House No.	Discharge in GPM	Discharge in Lit/hr	Head in ft	Head in m	HP	Maximum discharge in MLD
No. 2	18000	4903200	75	22.86	400	117.68
No. 3	28000	7627200	75	22.86	500	183.05
	51000	13892400		Total	900	300.73

 

If 20 hours working is assumed for each pump (However, pumping should be continuous working at least one pump in operation in each pump house) 250. 60 MLD are still available.

Saving in chemicals per day

Chemical	Dose ( in ppm)	Quantity in kg	Rate (Rs. per MT)	Amount in Rs.
Ferric Alum	50	11250	3450	38813
PAC	10	4950	7650	17212
Chlorine	25	11250	10900	61312
			Total	117337

 

Existing per day cost of chemicals on plant up to settling, Rs. 199307

Anticipated use of chemicals per day will cost Rs. 117337

Expected saving Rs. 81970

Why chemicals will be saved?

Pre chlorination is being done at present in the river. Water is channelized to the head works. Lifting is done by pumps. It is proposed to pre-chlorinate water whatever is pumped. Hence dose concentration will be more effective.

Further dosing will be done after proposed new Aeration fountain. Aeration will be effective to some extent for oxidation due to natural air. Hence, chemical oxidation will be required less.

Chlorination will be done in the channel and it will be allowed to mix properly and hence the given dose will be effective.

Energy level in the channel will be much more than normal river flow and it will encourage the transfer of chemicals and reaction will be more fruitful.

Alum and PAC dose is proposed to be given just after pre chlorination and it will help stabilization of the reaction.

Energy will be further utilized to move through Horizontal filters (proposed specifically) to have the better reaction opportunity with organic matter which is strained in the media boxes in series, at low velocities.

The process will ensure the effective pre-chlorination with 50% dosing level.

Advantage of Horizontal filters in the system

1. It is a simple method of aerobic series filtration.
   
2. It uses coarse media.
   
3. Particularly in this case limestone with 80 mm to 100 mm size media will be preferred.
   
4. If available, plastic/synthetic media also can be used.
   
5. Algae and other biodegradable material has chance of oxidation and trapping.
   
6. Due to low velocities fitration is better and it is improved with series media boxes.
   
7. In between blank boxes indicate the effectiveness in series and allow time for the flocks to form.
   
8. Though a mechanical process, allows better chances of removal of dissolved impurities.
   
9. Choking is an indication of effectiveness.
   
10. Choking does not stop filtration process, and water runs over the box to next media box.
    
11. In that process blank box acts as a cushion.
    
12. There are 8 streams provided and for clearing purposes one stream can be closed at a time.
    
13. Sufficient cleaning space is provided.
    
14. Effective velocity through filters is about 0.2 m/sec.
    
15. Limestone will be useful for increasing pH and for comparatively effective dosing.
    
16. Flow recording can be done in the Inlet / outlet channel of Horizontal filters.
    

Automation

1. Raw water quality parameters such as DO, NO2, NO3 and pH are proposed to be measured on line at periodic intervals.
   
2. Raw water pumping in both Pump house No.2 and Pump house No.3 are proposed for complete automatic operation with due recorders of all data regarding all concerned parameters of pumping. Electric substations will also be covered for automation.
   
3. Flow of water in the delivery lines is proposed to be measured and cumulating is recorded automatically with a tally of recording the flow in the fountain channels.
   
4. Chemical dosages are proposed to be decided automatically.
   
5. Actual dosing will be cross checked.
   
6. Quality parameters of DO, pH and NO3 will be measured at the outlet of Horizontal filters and outlet of settling tanks and at clear water reservoirs.
   
7. Filter operations are proposed to be done automatically.
   
8. Flow, Water levels at salient points in the system will be measured and displayed on a common screen for control.
   
9. Clear water reservoir levels will be displayed on a common screen.
   
10. Clear water pumping operations are proposed to be automatic along with display of activities on the common screen. Flow measuring of clear water pumping outlets is proposed to be continuous and displayed.
    
11. Finally total water going outside the plant will be checked and tallied with inflow and losses of water on plant will be displayed.
    
12. MIS regarding staff, on duty staff, Material, machinery and chemical inventory is proposed to be computerized.
    
13. Automation with PLC and SCADA is necessary for efficiency improvement.
    
14. Control rooms well equipped with all facilities can be suitably developed below Aeration fountain along with regular office, meeting and training hall.
    
15. Process will be computer controlled as far as the plant is concerned.
    
16. Necessary awareness and skilled operations training is also proposed to be undertaken.
    

Hydraulic Design of Aeration fountain and Horizontal filters

Hydraulic design of aeration fountain and Horizontal filters is enclosed in excel format 2007 version. General basis of design is as per the CPHEEO manual. Regarding Horizontal filters application on the large size plant is proposed particularly considering the requirement of the situation. For this purpose flow has been split up into no. of streams and each stream is provided with series of 7 media beds. Flow through velocity is also kept minimum. Major constraint for not providing these units is the space. But in this case space can be made available. All launders and channels are proposed to be painted with plasti-coated paints.

Aeration fountain has been proposed with 6 cascades and a total fall of more than 2.25 m. Overall plan area is about 675 sq.m. It will be a full RCC structure. An explanatory drawing prepared in excel is also enclosed separately in separate worksheet.

Space below Aeration fountain and HF

Space below is quite large. It can be utilized for significant purpose. Particularly for plant office, laboratory, meeting hall, training hall, control room with computers.

Repairs to civil structure and recondition

Civil structures for pump houses filtration plant and other process units are proposed to be renovated. They should be painted.

Replacement of Panel boards in Raw and clear water pumping machinery

All the panel boards are proposed to be suitably replaces and all the gauges, meters are kept in working condition. Incoming and outgoing cables be checked.

Impellers of Raw water pumping machinery to be renovated or replaced with proper grade of SS and similarly Motors be checked for winding resistance and overall insulation, earthling. All electrical installations of the concerned pump houses are proposed for checking as per I.E.Rules.

All chlorinators' assemblies shall be checked with Indian Explosives act.1981.

Laboratory set up

Complete renovation and updating of laboratory facilities is essential. It should include replaced of old equipments and replenishing of required chemicals and adding new required equipments as prescribed by the CPHEEO manual. It is also essential to built up the record of sample testing results.

Status report

No. of photographs showing the status of existing plant components are taken and will be appropriately inserted in the main report.