Evaluation of bacterial profile and biodegradation potential of abattoir wastewater

Abstract

Abattoir wastewater treatments were monitored using physicochemical parameters, bacterial profile and biodegradation potential for 28 days at 7 days intervals. The stages of abattoir wastewater treatment were evaluated through determination of physicochemical parameters such as pH, conductivity, total dissolved solid, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, phosphate, nitrate and iron using standard procedures. Bacterial plate counts were determined using the pour plate method with nutrient agar. Characterization and identification of bacteria was done on the basis of cultural appearance of colony, morphology, differential and selective media. The results showed that Escherichia sp., Pseudomonas sp., Enterobacter sp., Klebsiella sp., Staphylococcus sp., Salmonella sp., Streptococcus sp. were common to both abattoir wastewater samples. Serratia sp. was identified only in Ikpoba Hill abattoir wastewater. The bacteria occurrence frequency revealed that Escherichia sp. was dominant (P>0.05) in both abattoir samples while Streptococcus sp. was least abundant. Bacterial plate count revealed significant increase in both abattoir wastewater samples. BOD 5 /COD ratio revealed that degradation was slow below normal limit of 0.6, and then significantly increased with time. Physicochemical parameters showed significant difference at P>0.05 for both abattoirs. These results suggest that temporal variations of the effluent bacterial community may be useful to predict the wastewater treatment performance and settleability of activated sludge.