Microbial and Physiochemical Quality of Effluent Water from a Brewery in Benin City, Midwestern Nigeria

Aims: The present study w as set up to investigate the physicochemical and microbial contents of waste water discharged into the Ikpoba Rivers as well as water samples obtained from the river at different points of collection with a view to determining impact on the water body.
Study Design: The design chosen for the study was complete randomization, considering the homogeneity of the experimental plots from which samples were collected.
Place and Duration of Study: Samples were collected during the late rainy season of August 2012 from both the Ikpoba River, Benin City, Nigeria and from effluent treatment plants in a brewery in Benin City.
Methodology: Samples were collected in three different locations; in the brewery, from the brewery effluent samples point, as well as in the Ikpoba River, where brewery effluent samples mixes with the river water. Non-effluent samples were also collected from the brewery, these included glycol, condensate, boiler feed, brew cold and cooling tower water (CTW). Samples of the brewery effluent discharged into the river were also collected from the brewery effluent samples channel. On the Ikpoba River, five different sampling point were identified; contact point (CP) of the discharged brewery effluent samples with the river water, 5m and 10m before contact point, as well as 5m and 10m after contact point, respectively.
Results: The pH of glycol was 7.8, compared to those of the condensate and boiler feed which were both 5.8 and 5.5 respectively. The pH of the brewery effluent samples was 5.8, however at the point of contact of brewery effluent samples with Ikpoba River, pH dropped to 4.8. The surface water temperature ranges of non-effluent samples materials was 29.6 – 29.9ºC, as compared to 29.2ºC which was the temperature of the brewery effluent samples before contact with Ikpoba River. The heavy metals detected in the non-effluent samples and brewery effluent samples samples were iron, magnesium, copper and zinc. Lead was only detected in the non-effluent samples while nickel and vanadium were not detected in both samples.
Conclusion: Results showed that the effluents samples from the industry altered the physical, chemical and biological nature of the receiving water body. However, comparison with WHO and FMENV standards showed no deviation from required benchmarks, and as such the samples were adjudged ecologically safe.