Impact of effluent from Lubigi Sewage Treatment Plant on Nsooba Channel water quality

Abstract

The discharge of unregulated industrial wastewater effluent from point sources into inland fresh water aquatic systems coupled with the resultant deterioration of water quality, are largely un-documented in many less developed countries, Uganda inclusive. The aim of this study was to assess the impact of effluent discharged from Lubigi sewage treatment plant on the water quality of the surrounding environment. In order to achieve this aim, water samples from four sampling points were carried out namely; upstream, discharge point, mid-stream and lower stream with the distance of 100 meters between each sampling point along Nsooba channel. Water samples were analyzed for physico-chemical parameters including; temperature, dissolved oxygen, Ph and total dissolved solids, as well as Escherichia coli for microbial test. Field measurements were carried out using water quality instruments after calibration with standard buffers (3.3). Inorder to evaluate contamination of Nsooba channel by domestic wastewater "using E. coli as an indicator organism”, pour plate technique was conducted using a Chromocult Coliform Agar. Lubigi wastewater effluent exhibited significantly higher values of E. coli (277133cfu/100ml), total dissolved solids (2900pmm), temperature (22 0 C), pH (7.567) and dissolved oxygen (-1.367mg/L) compared to both upstream and downstream locations along Nsooba channel. It was thus concluded that the discharge of Lubigi wastewater effluent significantly impacts the water quality of Nsooba channel. It is therefore imperative that Lubigi sewage treatment plant sufficiently undertakes the task of pre-treating its wastewater effluent before discharging it into Nsooba channel.