CONSERVATION OF TREATED DRINKING WATER

             CONSERVATION OF DRINKING WATER 

               INDUSTRIAL TOWNSHIPS

 

 

 

 

INTRODUCTION

 

The expansion of township is inevitable with the increase in population and passage of time. The mushroom growth leads to imbalanced civic amenities, like drinking water, sewage, & drains. Therefore every decade or so there is a need to upgrade the civic amenities to meet the growing population demands. Drinking water is the first basic need of a man. Normally additional facilities are added on to the old installations for paucity of funds and the situation managed somehow. This is a case of an Industrial township, where the management felt a need to look into the problems of drinking water supply.

 

OBJECTIVE

To assess the existing capacity on a zero base and redesign the age old systems on a modular basis, with latest technology for the next 20 years.

 

FINDINGS:

 

A)  STANDARD AMOUNT OF WATER NEEDED

 

A realistic approach was adopted to assess the actual needs of water for a family of four persons (Two adults and two children) as follows:

 

Bath	3 gallons/person
Clothes	3 gallons
Toilet	2 gallons
Cooking	2 gallons
Miscellaneous	2 gallons
Total	12 gallons/person
Total for 4 persons	12 x4=48 gallons/day
Wastages at 100%	48 gallons/day
Grand Total	96 gallons/day

 

This norm matches with the highest government norm for a family four -100 gallons/day, for an industrial township.

B)  ACTUAL QUANTITY OF WATER SUPPLIED

The rate of flow from a 15 mm diameter pipe line in a house of the family of four is 7 gallons per minute. The supply hours I day are as follows:

 

5 am - 7 am	120 minutes
11 - 12..30 pm	90 minutes
6 pm - 8 pm	120 minutes
Total	330 minutes

 

Therefore total quantity of water supplied / day is 2400 gallons. This is exactly 24 times the amount of water needed It was a revealing observation leading to an obvious solution to contain the gross wastages.

 

C)  THEFT OF WATER

 

The crime rate in an industrial township is higher than other cities, because of higher purchasing power of the population. The villages and lower income group make illegal taping’s in the rising mains to fulfill their basic needs. The poor workmanship of these tapings leads to double wastages: continuous flow of water to the villages over the surface and undetected leakages at the tapings, below the surface.

 

D)  DILAPIDATED PIPELINES         

 

The water towers and the pipelines delivering the drinking water are 70 years old. Moreover they have been over loaded to cater to the mushroom growth of the township over the decades.

Since this civic amenity is round the  year.  Shutdowns are postponed till a major crisis erupts. This attitude leads to leakages from errored pipes, old valves and joints. The quantity of leakages could well equal the consumption of water supply to the township.

   

E)   LEVEL DIFFERENTIALS LEADING TO POOR PRESSURE

 

This industrial township is undulating and slightly hilly. It has a mix of single storied houses built in 1910's and 1940's as well as multistoried buildings built in l980's and 1990's Therefore on any-one delivery line. The level differential could be as high as 12 meters. The management is supplying 2 hours of water to a multistoried building twice a day simply because the level differential reduces the pressure in delivery line and water keeps over flowing from single storied houses till the multistoried flats have had their fill.

 

F)    OVERFLOWS AT THE WATER TOWERS

 

The over flow for 120 min/day from a house-hold tap, 15 mm diameter pipe at the rate of 7gals/min. would work out to 2 lakh gallons per year. This will cost the corporation $200 per year only. But a normal over flow from a 600 mm diameter pipe at the main water towers at the rate of 2500 gallons per minute for a short period of 10 minutes per day would work out to 91 Lakh gallons per year costing $50,000 per year to the corporation.

 

G)        LEAKAGES AT THE WATER TOWERS

 

The age old delivery lines and their corresponding valves are worn-out heavily. But there is no time available to shut down the system and replace them, when the valves are fully closed. The water still leaks past the gaps up to 10 %. This minor 10 % is seemingly a small loss and can be overlooked, until quantified. So it was done to get the accurate picture. The 10 % loss from a 600 mm delivery pipe line at the rate of 4600 gallons/min works out to 460 gals/min. The total amount of water leaking past the worn-out valve is 5 lakh gallons/day which works out to cost of $11,00,000 per year.

 

H)         ORGANIZATIONAL SET UP AND REPORTING SYSTEM

 

 

The raw water treatment plant is managed by one executive agency whose targets are based on demands of the Industry and township put together. He operates independently with little interaction on the supply and consumption side.

The supply of treated water is looked after by another executive agency whose norms are customer satisfaction first at any cost.  Since whatever demands they make on the treatment plant are met regularly. The need for improvements and savings is not felt, so far. This organizational set up has it draw-backs, No one is held accountable for total costs of the system. For the fear of public reactions and uproar, the improvement plans/ideas are shelved in favour of status quo.

 

 

       RECOMMENDATIONS :

 

1. It is proposed to reorganise the delivery pipeline network, with minor modifications to minimise the level differentials up to one meter only and reduce the supply hours in a tapering fashion – (New law of tapering demand by the author).
2. It is proposed to close the head end valves at the water towers, on these delivery lines by 15 % every 10 minutes interval. This break-through will contain wastages of water up to 40 % without sacrificing the function of supplying water to the customers for a full supply of one hour duration.
3. It is proposed to modernise the delivery pipe line system at the water towers on the common header system, having three distinct but interconnected segments; low pressure segment, medium pressure segment and high pressure segment. Standby valves on this common header will ensure regular maintenance without affecting the water supply activity, which will contain the leakages happening after the supply hours.
4. It is also proposed to motorise the valve opening and closing operations at the water towers from a central control room to optimise the manpower deployment. 
    
5. It is recommended to interconnect the overflows of the three storage tanks at the water towers. The overflow of 'A' would act as inlet to 'B' and the overflow of 'B' would be the inlet to 'C'. This will mean that we continue to fill up tank 'A' only at all times and stop this process when 'C' overflows. This will eliminate the individual operations and individual overflows from the storage tanks, which is substantial.
6. It is recommended to install bore wells in villages and low income group housing to obviate the theft of water and the consequential losses arising out of illegal tapings. It has been found to be very economical to provide a bore well in the long run.
    

 

           CONCLUSION:

 

On completion of these proposals the expected savings / benefits would work out to around $2,000,000/year recurring. The investment level is around $800,000. The ROI is very lucrative. Figures are based on the year of study 1990-91.

 

 

Rohit Khanna – Author of Futuristic designs for manufacturing sector.