The cyanide component of cassava mill effluent CME is highly toxic to man and it environment. This research was assessed using various concentrations of cyanide with variable concentrations of pH values, inoculum size and phenol, an inhibitory substance. The heterotrophic bacterial and fungal counts were 6.32 x 108cfu/ml and 2.87 x 108cfu/ml respectively. The microorganisms isolated and characterized were: Staphylococcus aureus, Bacillus, Escherichia coli, Lactobacillus, Micrococcus, Klebsiella, Pseudomonas, Salmonella, Corynebacterium, Aspergillus niger, Penicillium, Fusarium and Saccharomyces species. The physicochemical parameters; pH (4.81), electrical conductivity (4860uS/cm), cyanide (17.13mg/l), chemical oxygen demand (2041.20mg/l), biological oxygen demand (1490.08mg/l), total dissolved solids (2478.60mg/l), cations and heavy metals such as Chromium (19.44 mg/l), Manganese (136.08mg/l), Iron (340.20 mg/l) and Nickel (121.50mg/l) were above the Federal Environmental Protection Agency standard for effluent discharge. Bacillus, Pseudomonas and Aspergillus species which had the highest turbidity were used for the batch biodegradation studies. The result revealed that cyanide concentration of about 30ppm at pH 6 with inoculum size 6.5ml gave the highest cyanide degradation ability of 32.73% using Pseudomonas sp. at a residence time of 8 days. It was also found that the same organism gave the best degradative ability in the presence of phenol, an inhibitory substance. The findings revealed that Pseudomonas sp. and Bacillus sp. can be utilized for remediating cassava mill effluent contaminated environment containing cyanide.
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