Assessment oflndustrial and Municipal Effluent and Urban Run-off Loads Discharged into Lake Victoria from tbe Uganda Catchment

Abstract

An assessment was carried out to determine the pollutant loads discharged into Lake Victoria from industrial and municipal sources as well as the contribution from urban run-off from the Uganda catchment from 1997 to 2000. This study was part of the Lake Victoria Environmental Management Project (LVEMP). The paper outlines the outcome of a case study which was the first ever done to quantifY pollution loading into Lake Victoria emanating from municipal /urban and industrial sources located in the entire part of the lake catchment of Uganda. Similar work was carried out simultaneously in Kenya and Tanzania. Most urban centres and fishing villages with a potential pollution threat to Lake Victoria were identified. Similarly, factories in Kampala, Jinja and Entebbe with potential pollution threats have been identified. The results show that urban centres contributed a daily load of 6.17 tonnes BOD, 1.43 tonnes of nitrogen and 0.98 tonnes of phosphorus. 1.88 tonnes BOD, 0.26 tonnes of nitrogen and 0.13 tonnes of phosphorus are discharged daily from the 124 fishing villages with a total discharging human population of 92,000. Industrial loads reaching the lake were estimated to be l tonne BOD, 0.1 tonnes nitrogen and 0.1 tonnes phosphorus per day. Contrary to the previously long held perception that industries were responsible for much of the pollution loading entering the lake, this study demonstrated that the major pollution loading entering the lake was actually from the urban centres; they accounted for nearly 70 % of BOD and 80 % of other nutrient loads. Kampala accounted for about 60 % of the discharging population and 65 % of the total BOD load. Pollution management strategies proposed for urban centres should therefore focus on improved garbage collection and sanitation, particularly in the Nakivubo catchment of Kampala. There is a need also for a more proactive approach for the protection of wetlands since the study showed the significant role they play in the reduction of pollution loads. Sanitation improvements advocated include improved operation and maintenance of the existing municipal wastewater treatment works, strengthening of process engineering expertise (Cleaner production) and greater on-site sanitation coverage. Similar sanitation recommendations apply for fishing villages, but here, the strategy should be focused on improving the ability of fishing village communities to help themselves and access existing sanitation programmes. The strategy for industry is the use of the Pollution Control Manual produced for training and guidance, strengthening of process design capacity, a staged approach to treatment plant development, and strengthening of Discharge Agreements.

Keywords: Pollution loads, Municipal waste, Urban run-oft: Fishing villages, Industrial diluent, Lake Victoria