Reduction of bacteria and other pollutants in sewage stabilization ponds.

Abstract

Management of water resources is one of the biggest the problems facing developing countries today where sewage water treatment plants only serve the urban population. The rural areas and informal settings often lack mechanisms of sewage water treatment thereby posing potential harm to the environment. Different sewage water treatment options must therefore be developed to protect the environment. Sewage Stabilization Ponds (SSPs) are artificially constructed ponds that use biological treatment mechanisms to purify sewage water. They are simple to construct and maintain, have low capital investment and annual running costs, and also require less skilled personnel. This study evaluated performance of SSPs to determine whether they can efficiently treat sewage. It was conducted at the University of Eldoret sewage treatment plant which has 4 SSPs. Performance of these SSPs was achieved by determination of numbers of bacteria and levels of physicochemical pollutants in the sewage water at 5 different points (raw sewage influent, pond 1 effluent, pond 2 effluent, pond 3 effluent and pond 4 effluent) for10 months. Results indicated that levels of all physicochemical parameters, except pH, temperature and total suspended solids reduced significantly (p<0.05) from one station to the next and the least values were recorded for station 5. The numbers of bacteria, except for total bacteria counts, reduced significantly (p<0.05) from one station to the next and the least values were recorded in station 5. Thus, SSPs are effective in sewage water treatment and can be adopted in small communities to protect aquatic environments and alleviate contamination of drinking water sources.