Treatment of abattoir wastewater using <i>Moringa oleifera</i> seed and snail shell in Rivers State, Nigeria

Abstract

The practice of discharging abattoir wastewater into a receptacle without treatment is most likely to alter its physicochemical and microbiological properties. Against this background, this study is aimed at determining the efficacy of Moringa oleifera and snail shells as bio-coagulants for treatment of abattoir wastewater using the jar. The mean values of monitored physicochemical parameters were electrical conductivity (1227.7), total organic carbon (224.4%), biochemical oxygen demand (362.3 mg/l), chemical oxygen demand (1001.5g), total dissolved solids (462.5 mg/l), total suspended solids (1562.5) mg/l and turbidity (190.6 NTU). The mean total heterotrophic bacteria count (THBC) for untreated wastewater was 1.4 x 108 CFU/ml, total coliform count (TCC) was 5.6 x 10⁵ CFU/ml, and total fungal count (TFC) was 1.6 x 10² CFU/ml. After treatment, the biocoagulants caused 82.5-84.2% reduction in EC, TOC (59-88.3%), BOD (90.8-93.7%), COD (94.4-95.3%), TDS (89.6-91.9%), TSS (93.3-94.5%) and turbidity (80.8-84.5%). The bio-coagulants were able to remove 92.2-95.4% of Zn, Pb (97-97.5%), Cr (97.2-98.8%) and Cd (86.7-89.3%). After treatment with the bio-coagulants, THBC dropped from 4.7 x 10³-5.3 x 102 CFU/ml to 8-10 CFU/ml on day 6, TCC dropped from 4.2 x 10² – 6.7 x 10 CFU/ml to 5-7 CFU/ml on day 6 while TFC dropped from 1.1 x 102 - 1.5 x 10 CFU/ml to 2-4 CFU/ml on day 6, representing approximately 99.9% reduction in microbial load. Thus, the bio-coagulants were as good at removing pollutants in water as alum, but with the added advantages of being natural, cost-effective, and readily available.