The Manchinchi Sewage Treatment Plant in Lusaka aims to reduce harmful microorganisms in sewage before releasing it into the Ngwerere stream. By analyzing samples from different treatment stages, researchers found that coliform bacteria levels decreased from raw sewage to the final effluent, but were still slightly high due to plant overload. Faecal coliforms in the final effluent exceeded recommended levels, indicating inefficiencies in treatment. Protozoan populations were not a major concern, but the counting method may underestimate their actual numbers.