Abstract

In Malawi, the requirement to treat wastewater is underscored by the existing regulatory framework, institutional arrangements, and policy guidelines. In addition, formalized national effluent standards exist. This study was conducted to determine the pollutant levels in effluent from municipal wastewater treatment plants in the city of Blantyre, Malawi, and to compare these with Government of Malawi standards and World Health Organisation (WHO) guidelines. Data on physicochemical characteristics of the effluent was collected through a desk study. This study established that Biochemical Oxygen Demand (BOD₅) and Total Suspended Solids (TSS) levels in effluent from the three major wastewater treatment works in the city are in most cases above the recommended Malawi standards and WHO guidelines.  Levels for heavy metals are all lower than the recommended standards except for Cadmium, in the dry season effluent at Limbe wastewater treatment works. In view of the pollution threat posed by the high levels of BOD₅ from the three works, the paper recommends that the assimilative capacity of the receiving watercourses be ascertained to determine the impact of the organic and solids loading in the final effluent upon the aquatic flora and fauna.

Key words:  Aquatic flora and fauna, effluent, municipal wastewater treatment, physicochemical characteristics.