Potential Impacts of Kirinya Wetland in Treating Secondary Municipal Effluent from Jinja Stabilisation Ponds

Abstract

Kirinya West wetland is located on the Northern shores of Lake Victoria in Jinja- Uganda. The wetland receives secondary treated effluent from the stabilisation ponds owned and operated by the National Water and Sewerage Corporation. The effluent finally enters Lake Victoria at the Napoleon Gulf. ln this paper, we report the baseline water quality before the bio-manipulation of the wetland and demonstrate the impact of Kirinya West wetland in treating secondary municipal effluent from the existing waste stabilisation ponds. The bio-manipulation of the wetland will entail spreading the effluent from the stabilisation ponds over the northern edges of the wetland so as to increase the treatment area of the wetland and its treatment efficiency. Bio-manipulation will increase the current treatment efficiency of the wetland, as the contact between plants and the wastewater will increase. The baseline data indicate that there was significant improvement of water quality as the wastewater flowed through the ponds (61% decrease in NH_4-N, 46.9% in P0_4-P and 98% in faecal coliforms). There was a further reduction in the concentration of pollutants (80% for NH_4--N and 98% for faecal coli forms) as the wastewater flowed through the wetland before reaching Lake Victoria at the Napoleon Gulf. However, channelised flow allowed wastewater to flow at the western edge of the wetland and this is associated to the effluent from the stabilisation pond that discharge at the northwestern edge of the wetland.

Keywords: Bio-manipulation, Kirinya West wetland, Lake Victoria, Wetlands, Wastewater treatment