Evaluation of Solid Waste Management Practices at Chemical Manufacturing Plants in Ogun State

Industrial solid waste generation from chemical manufacturing in Ogun State, South West Nigeria, where the Sagamu and Sango-Ota industrial clusters are concentrated, poses risks to soil and groundwater in surrounding communities due to inadequate waste characterisation and disposal practices. This study evaluates solid waste management practices at eight chemical manufacturing facilities in Ogun State against the requirements of the Nigerian Environmental Impact Assessment Act and the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes. Data collection employed structured waste management audits, facility waste register review, and interviews with environmental health officers. Waste categories assessed included spent catalysts, filter cakes, packaging contaminated with hazardous materials, off-specification products, process sludge, and general industrial waste. Results revealed that only two of eight facilities maintained a compliant industrial waste register with hazardous waste classification under NESREA regulations. Three facilities disposed of filter cake containing zinc and chromium above hazardous thresholds in municipal solid waste landfills without special waste manifests. Hazardous waste contractor due diligence was not practised at six facilities. The study identifies regulatory knowledge gaps among environmental compliance officers at small-to-medium enterprises as a primary driver of non-compliant disposal. Recommendations include mandatory waste characterisation protocols, a state-level hazardous waste manifest system, and capacity building grants for SME environmental compliance in Ogun State. Keywords: industrial solid waste, hazardous waste, chemical manufacturing, Ogun State, NESREA