Assessment of Effluent Characterisation and Treatment Needs at an Abattoir in Ibadan, South West Nigeria

Abattoir effluents containing blood, offal washings, fat, manure, and pathogenic organisms present severe organic and microbiological pollution challenges when discharged untreated into drainage systems or water bodies, a condition prevalent at municipal slaughterhouses across South West Nigeria. This study characterises the effluent produced at a municipal abattoir in Ibadan, Oyo State, South West Nigeria, and assesses treatment needs relative to applicable discharge standards. Effluent samples are collected from four production zones: lairage washdown, slaughter hall, offal processing, and final washdown drainage, at morning and afternoon slaughter shifts. Parameters measured include pH, temperature, total suspended solids, biochemical oxygen demand, chemical oxygen demand, total nitrogen, total phosphorus, oil and grease, total coliform, Salmonella spp., and faecal coliform counts. Pollutant load calculations incorporate effluent volume measurements. A comparative analysis of appropriate low-cost treatment options for abattoir wastewater, including anaerobic lagoons, constructed wetlands, and up-flow anaerobic sludge blanket systems, is conducted based on performance data from peer-reviewed literature and economic feasibility assessments relevant to a Nigerian municipal setting. A treatment system sizing recommendation is presented, along with sludge management and co-treatment options involving co-composting with market solid waste. Findings provide the Ibadan municipal authority with a technically sound and financially realistic abattoir wastewater management action plan. Keywords: abattoir effluent, wastewater treatment, Ibadan, biochemical oxygen demand, constructed wetlands