Effects of Cassava Wastewater on the Quality of Receiving Water Body Intended for Fish Farming

Abstract

Aim: The goal of the study is to determine the suitability of a pond into which cassava mill wastewater is discharged for fish farming. The pond which is located adjacent the Faculty of Engineering of the Delta State University, Oleh Campus is currently being proposed for acquisition by the Faculty for the project. Methodology: A total of 13 physicochemical parameters were analysed from samples collected at four different points around the pond. The parameters investigated were pH, CN, BOD, COD, DO, turbidity, conductivity, hardness, Pb2+, Hg2+ and Fe2+. The TSS, TDS, DO, total hardness were determined by the UV absorption spectrophotometer at 220 and the metal ions at 420nm respectively; while the Winkler’s titrimetric method was used to determine the COD and BOD. The pH, conductivity and turbidity were determined using the pH meter, conductivity meter and turbidity meter respectively. Results: The average cyanide content at the discharge point over the four weeks experimental period was 39.0±1.69 with a highly significant effect (p=0.042) and the lowest value of 3.8±0.01 mg/l was recorded 10 metres downstream of the discharge point. The COD, BOD, TDS and TSS at the discharge point were 1236±0.63 mg/l, 430.7±0.53 mg/l, 975±0.90 mg/l and 4030±9.26 mg/l respectively; while the Pb2+ and Hg2+ were higher at the sample point close to a refuse dump. Values recorded for all the tested parameters were far higher than that recommended for water bodies suitable for fish farming. Conclusion: The pond cannot be used for the intended project at its present form, it could be considered for use however, if all sources of pollution are stopped with proper remediation.