Cost Evaluation of Water Treatment Plants in Kenya

Abstract

The thesis deals with costs of different production methods of potable water in Kenya. Water supplies in this country involves construction of treatment plants for surface water and groundwater sources, and also the running of these facilities. Plant construction and running is expensive and needs qualified people in all stages of planning, design, implementation and running. The funds used for a water supply scheme should yield the best possible output. The treated water should be of high guality and enough inquantity to meet the demand. In the planning of water treatment plants big savings are possible by selecting the most appropriate processes, materials and construction methods. Proper selection also has a great impact on running costs which must be taken into account already in the planning stage of a treatment plant. A treatment plant could simply be defined as any construction that produces potable water. The origin of the water is precipitation. Rainwater harvesting has been considered and is a goods upplimentary source of water. Using local material any family can afford to store rainwater. Therefore the investment costs should range from zero up to Kshs. 1430 per capita depending on storage construction. Running costs are almost negligible. Shallow wells can speed up the provision of water program in rural areas. The investment costs are Kshs. 170 - 230 per capita and with a good maintenance program the running costs are also low (Kshs. 10 per capita). This kind of program should run in hand with spring protection which requires little maintenance and the investment costs are lower (Ksh. 100 per capita). The groundwater potential in this country as a whole is yet to be assessed. Boreholes have an investment costs of Kshs. 900 per capita on the basis that no treatment except chlorination is required. Running costs varies between Ksh. 1 - 25 per capita because of fuel and labour. Boreholes have an advantage over surface sources over greater simplicity of operation. Surface water treatment plants are financially and managerially burden some. The river appears to be the source because of its immediate availability, but because of the character of the water, complete treatment is required in most cases. Failures are inevitable in treatment plants because of spares, maintenance and water utility operator experience. However, gravity supplies cost much less. The investment costs in treatment plants range from Kshs. 13 to over 707 per capita. If the plant is well run over design life, the unit capital cost of treated water can be very low (Kshs. 0.10 to over 1.50 per cubic metre). Running costs are quite high (Ksh. 0.28 to over 30 per cubicmetre). These costs vary so much because of the difficulties of assessing the data available. Recording is not consistent, especially on maintenance and expenditures qn electricity bills in most plant operationcharts. Scale of economies exists; smaller plants (<100,000 m3/year) spend more per unit production of water than larger plants. Medium plants fall within 100,000 - 300,000 m3/year of treated water produced. But proper capacity sizing of treatment plants should be done with due regard of transmission (distribution) costs. Alternatively, use of package plants should be investigated. The number of operating water supplies by MoWD is increasing, resulting in a growing burden of finance, administration, transport, procurement and staff management. There are advantages of centralized management e.o. cheaperbulk purchases, but services rendered will deteriorate as the number of schemes increase. Decentralization at certain levels (Provincial or. District) should be considered. /Kir09