The effect of cassava processing effluent on the physico-chemical and microbiological characteristics of receiving rivers in Oyo and Ilora, Nigeria.

Abstract

In Nigeria, Cassava is important for production of staple food like: Gari, Lafun, fufu etc. Over 70% of Cassava is processed into Gari, during which expressed juice causes pollution. Wet season pollution of water bodies proximate to Gari processing sites in Olokomeje and Iyalamu in Oyo and Odo-Aro in Ilora, Oyo State, were evaluated. Samples from -5-lOM Up-Stream, Down-Stream, Effluent and Contact Point were tested using standard analytical procedures. Physico-chemical characteristics revealed higher values in Cassava effluent and Contact Point. Values are: Temperature: 25±1°C, pH 4.3-7.4; Colour :l-10 Hazen Units; Turbidity (mg/L Si02) 5-42; Dissolved solids-350-655 mg/L; Suspended solids-154-2750 mg/L; BOD:l0-1525 mg/L; COD <5- 1250 and Cyanide <0.1 -19.51 mg/L HCN. Microbiological counts revealed Bacteria: Bacillus sp, Pseudomonas sp, Staphylococcus sp; Enteric Bacteria: Aeromonas sp, Enterobacter sp E.coli, Klebsiella sp, Proteus sp. and Fungi: Aspergillus sp, Candida sp, Fusarium sp, Geotrichum sp & Penicillium sp. The Effluent had fewer coliforms and no fungal isolates in Down-Stream samples. Cassava effluent and human activity polluted the water bodies. Since the Iyalamu river ended in Oyo town municipal water supply, there is the need to treat cassava effluents before discharge to protect the populace from water associated chronic exposure to sub-lethal cyanogens.

Key Words: Cassava, Effluent, Bacteria, Fungi, Physico-chemical, Pollution.