| Title |
A Case Study on the Rehabilitation and Design of Economical Surface Water Treatment for River Intakes in Sri Lanka |
| Authors |
이승환(Seung Hwan Lee),기니게(S . G . Ginige) |
| Abstract |
Water supply scheme selected for rehabilitation was an existing system in a depleted condition, which provides water for 45,000 people living on the outskirts of Kandy. In its existing state with worn out pumps and leaking pipelines, the supply of water was limited to 2-3 hours per day. The rehabilitation of this river intake was an opportunity to design, build and test an innovative system of filtering water as it leaves the river. Two filter beds were built on an artificial channel parallel to the direction of flow of the main river. Necessary piping arrangements had been provided for the filter beds for air scouring and high-pressure water for backwashing the filters. Important feature of this system is that the raw water directly fed into the filter system. Chemicals were not added for sedimentation, which makes the operations and maintenance of the system relatively easy and expensive. Four pumps are being used for pumping the filtered water collected into large diameter wells, directly to the main reservoir. New equipment for disinfecting water was fitted. The capacity was increased from about 2,000 - 6,000 ㎥ per day for the beneficiary population. The total cost of the work was US$ 1.0 million, which worked out to about US$ 28 per person. The quality of water supplied by this system is within Sri Lankan standards for turbidity, pH and total iron, but the color during the rainy season is above the maximum permissible level. However the average removal of color is more than 55 percent. |