Assessment of the efficiency of a yeast biofilter in the treatment of abattoir wastewater

Abstract

A yeast biofilter consisting of Candida krusei, Candida morbosa, Torulopsis dattila, Torulopsis glabrata, and Saccharomyces chevalieri was constructed to bioremediate abattoir wastewater. Potato peels were used as filter bed for the growth of the yeasts. Wastewater samples were collected from three different points in Sokoto (Nigeria) abattoir and the physiochemical as well as the microbiological qualities of the wastewater were determined before and after biofiltration. The results revealed that after the biofiltration process, the pH, biochemical oxygen demand (BOD), dissolved oxygen (DO), chemical oxygen demand (COD), and the nitrate content of the wastewater were drastically reduced. Similarly, there was a decrease in the variety of microorganisms isolated as well as in microbial counts after the biofiltration process. Salmonella typhi, Neisseria lactamica, Serratia marcescens, Branhamella catarrhalis, Shigella sp, Penicillium sp, Curvularia sp, and Trichophyton rubrum were completely eliminated after the biofiltration process. The reduction in the pH, BOD, DO, COD, nitrate as well as in the variety and total counts of bacteria and fungi for the wastewater after the biofiltration process indicated that the biofilter was effective in bioremediation of the wastewater. The percentage efficiency of the biofilter was found to be 42.5%.

Key words: Assessment, efficiency, yeast, biofilter, abattoir, wastewater.