A comparative study of the performance of the Chitungwiza, Marondera and Crowborough sewage treatment plants in Zimbabwe

Abstract

The performance of the Chitungwiza, Marondera and Crowborough Sewage treatment plants in Zimbabwe were evaluated by monitoring the levels of suspended solids (SS), dissolved solids (DS), dissolved oxygen (DO), biological oxygen demand (BOD), K+, Na+, Ca2+, Mg2+, CI-, S042-, N03‘, N02‘, and P043- ions in the period May 1994 to September 1995. The performance of the three plants were assessed by comparison to the UK conventional effluent 30:20 standard for SS, BOD, Cl', N03‘ and P043* ions. All three plants conformed to this standard for nitrate ion, while for Chitungwiza and Marondera plants the levels of BOD, SS, chloride and phosphate ions were in excess of the Standard. In addition, the Chitungwiza sewage plant effluent contained very high levels of nitrite ion.