MICROBIOLOGICAL AND PHYSICOCHEMICAL QUALITIES OF IKPOBA RIVER IMPACTED BY PIPED TREATED BREWERY EFFLUENT STREAM

Abstract

The impact of discharged treated brewery effluent stream on the microbial and
physicochemical qualities of Ikpoba River which is serving as a receptacle for the treated
wastewater was investigated. Serial dilution, pour plate and multiple tube technique were
employed in evaluating the culturable microbial diversity of the water samples and the
treated brewery wastewater. The physicochemical attributes of the freshwater and effluent
samples were ascertained using titrimetric and spectrophotometric procedures. The mean
heterotrophic bacterial counts for the upstream freshwater samples ranged from 3.7 ×102
cfu/ml ± 2.1 to 0. 6 × 102 cfu/ml ± 2. The mean heterotrophic fungal counts for water
samples obtained at the point of discharge ranged from 0.7×103 cfu/ml ± 6.6 to 9.7 × 103
cfu/ml ± 6.1. The total coliform counts recorded for water samples obtained at the
downstream sampling point ranged from 2 MPN/105 ml to 5 MPN/105 ml. The E. coli
counts for the treated brewery wastewater varied from 2 MPN/105 ml to 4 MPN/105 ml. The
observed differences in the mean heterotrophic bacterial and fungal counts was statistically
significant (P<0.05). Seven bacterial and four fungal isolates were characterized and
tentatively identified; Proteus vulgaris, Bacillus cereus, Klebsiella pneumoniae, Escherichia
coli, Streptococcus sp., Pseudomonas sp., Enterobacter aerogenes, Saccharomyces
cerevisiae, Candida tropicalis, Penicillium sp. and Aspergillus niger. The mean pH, turbidity
and conductivity of the respective samples ranged from 5.63±0.05 to 6.78±0.05, 4.1 NTU
±0.21 to 6.81 NTU ±0.55 and 3.3 ?s/cm ±0.25 to 73.3 ?s/cm ±6.56 respectively. The
discharged brewery effluent stream impacted negatively on the as aesthetic quality of the
Ikpoba River at the point of discharge. The microbiological quality of both the water
samples and the treated effluent is very poor when compared with Federal Ministry of
Environment limits for potable water, hence discouraging the direct consumption of the
water sourced from the Ikpoba River at these sampling points by individuals living along the
catchment area of the river