Characterisation Of Effluent Discharges From Edible Oil Producing Industries InBulawayo, Zimbabwe

The discharge of poor quality effluent by edible oil industries in the City of Bulawayo poses a threat to public wastewater treatment plants and water resources alike. Snap and composite samples of the liquid effluents were collected manually from manholes and discharge outlets from the two edible oil producing plants for a period of six months and analysed using standard procedures. The effluent did not meet the regulatory quality standards established by the municipality. The effluent was characterized by high values of soap, oil and grease (SOG), chemical oxygen demand (COD), sulphates, total dissolved salts and turbidity. Although one of the industries pre-treats its effluent before discharging it to the sewer, further treatment of the effluent is still necessary to meet regulatory standards. One of the industries discharges some of its very poor quality effluents into dumping pits.