Evaluation of wastewater treatment alternatives in Kenya

Abstract

Treatment of domestic and i n d u s t r i a l wastes is a recent endeavour in Kenya that became a requirement in every town soon a f t e r Kenya attained her independence some 28 years ago. During t h i s period, a tremendous change i n domestic waste c o l l e c t i o n and treatment has taken place in the e n t i r e country whereby d i f f e r e nt types of wastewater treatment a l t e r n a t i v e s have been constructed in various towns. Most of these treatment a l t e r n a t i v e s pose operation and maintenance problems due to t h e i r complexity, lack of spare parts f o r the broken machineries and equipment, lack of q u a l i f i e d s t a ff and lack of attention of these plants from senior c o u n c i l s t a f f. This report examines the design, construction, operation and maintenance of various e x i s t i n g treatment a l t e r n a t i v e s . Effluent data from a l l sources has shown a Biochemical Oxygen Demand (BOD) l e v e l almost constantly higher than the 20 mg/1 standard set for any effluent discharged into n a t u r a l r i v e r s. After comparing a l l the a l t e r n a t i v e s , i t has been concluded t h a t f a c u l t a t i v e waste s t a b i l i z a t i o n pond or oxidation d i t c h (where the topography of the land i s not s u i t a b l e for a pond) are best s u i t e d for future wastewater treatment in Kenya. These w i l l simply operation f a i l u r e due to lack of q u a l i f i e d s t a f f and avoid spare p a r t and maintenance costs.