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.