Abstract

 The study was conducted to determine the physicochemical quality and bacterial profile of waste water sample recycled using an immobilized biofilm system. Temperature, pH, turbidity, colour, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), and dissolved oxygen (DO) were analysed over a period of 2months. The parameters were analysed using standard methods. Microbiological examinations of the samples were carried out using standard microbiological methods. COD obtained from the samples during the course of treatment ranged from 2375.03±3.42mg/l to 904.32±0.0Smg/l. COD of eftluent before treatment was observed to be 2375.03±3.42mg/l, but after treatment for 9weeks, a COD value of 904.32±0.05mg/l was observed with a percentage reduction in COD content of 61.9%. Similarly, the overall turbidity removal efficiency was 39.7% after 9weeks of treatment. The mean TDS concentration of the influent wastewater was 2 I 47±2.82mg/l, and the final effluent after treatment for 9weeks was l 003.5±2. l 2mg/1. This showed that the treatment was able achieve overall mean TDS removal efficiency of 53.3% after 9weeks of treatment. The value recorded before treatment was 1 828.96±4.75mg/l. After treatment for three weeks, the value was decreased to 96S.08±0. I 8mg/l with highly significant difference between the influent wastewater and the effluent. The percentage reduction in BOD values recorded respectively for the 3, 6 and 9 weeks were 43.9%, 49.6% and 53.4% respectively. The pH of the wastewater stood at 8.28 and was observed to decrease during the course of treatment. The pH values of the effluent water after the 3, 6 and 9 week of treatment were 7.22, 7.09 and 6.89 respectively. The total coliform recorded for the influent wastewater reduced from 1.42 x 10 7 cfu/ml to 6.1 x 10cfu/ml of the final effluent discharged after 9weeks. Similarly, the total heterotrophic count recorded for the wastewater reduced from 2.16 x 10cfu/ml to I.72xl0 9 cfu/ml ofthe final effluent discharged after 9weeks. The results of this study revealed the occurrence of a total of 12 species of bacteria namely Escherichia coli, Klebsiella sp., Staphylococcus aureus, Salmonella enteritidis, Bacillus spp, Pseudomonas aeruginosa, Serratia marcescens, Enterobacter aerogenes, Proteus vulgaris, Micrococcus spp. and Streptococcus faecalis. Nitrosomonas europea, before treatment while 5 species namely Enterobacter aerogenes, Pseudomonas aeruginosa, Micrococcus spp, Staphylococcus aureus, Klebsiella spp, were isolated after treatment. The ability of the wastewater treatment bioreactor to effectively reduce some key parameters suggests that the treatment reactor was efficient