The Effects of Dashen Brewery Wastewater Treatment Effluent on the Bacteriological and Physicochemical quality of Shinta River in Gondar, North West Ethiopia

The objective of this study was to investigate the impact of Dashen brewery effluent on the bacteriological and some physicochemical qualities of Shinta River, Gondar town. Bacteriological and physicochemical quality assessments were carried out on samples collected at 13 different sampling stations; upstream, effluent, effluent discharge and 10 downstream stations in three replications. The bacteriological parameters; aerobic mesophilic count, total coliform count and fecal coliform count were done. The values of aerobic mesophilic count ranged from 3.0 105 cfu/ml to 2.64 107 cfu/ml. These counts were significantly different (p<0.05) among the stations sampled. The values of total coliform count ranged from 111 MPN/100ml to 396 MPN/100ml, and the values of fecal coliform count ranged from 96 MPN/100ml to 356 MPN/100ml. The counts of total and fecal coliform were significantly different (p<0.05) among the stations sampled. Microorganisms isolated include, Escherichia coli, Enterobacter aerogenes, Streptococcus faecalis, Staphylococcus aureus, Proteus vulgaris and Bacillus subtilis. The physicochemical parameters analyzed were temperature, total suspended solids (TSS), total dissolved solids (TDS) and Biochemical Oxygen Demand (BOD). The water temperature varies from 22 to 30℃. pH varied between 6.6 and 7.9. The values of TSS fluctuated between 6 and 42 mg/l, and the values of TDS fluctuated between 73 and 201 μs/cm, and BOD ranged between 3.8 and 23.0 mg/l. All the physicochemical parameters were significantly different (p<0.05) among the stations sampled. The results of this study show that all the physicochemical parameters of the brewery effluent were within the EEPA (Ethiopian Environmental protection Agency) and World Bank permissible limits.