Waste Disposal Practices of Offshore Oil Platforms and Marine Pollution in Nigerian Waters

Offshore oil and gas platforms in Nigeria's continental shelf waters generate diverse waste streams including produced water, drilling fluids, drill cuttings, food waste, domestic sewage, and solid waste, all of which carry potential for marine environmental impact if not managed in accordance with MARPOL and national regulatory requirements. This study evaluates waste disposal practices of offshore platforms operating in Nigerian waters, focusing on compliance with MARPOL Annexes I, IV, and V and the Department of Petroleum Resources' Guidelines for Offshore Operations. A structured questionnaire is administered to environmental management officers on 22 offshore platforms operated by eight different companies active in OML blocks across the Gulf of Guinea. The questionnaire assesses waste categorisation procedures, treatment technologies installed, disposal records, operator training, and regulatory inspection frequency. Produced water discharge data reported to the Department of Petroleum Resources are extracted and analysed for compliance against oil-in-water concentration limits. Water sampling around three selected platforms during a research cruise in 2024 measures total petroleum hydrocarbons, surfactants, and chemical oxygen demand at 500-metre and two-kilometre radii. Analysis of drill cutting pile characteristics from available sub-sea survey reports addresses seabed impacts of historical barite-weighted drilling waste disposal. Findings are expected to reveal widespread under-reporting of produced water discharge volumes and inadequate treatment capacity for sewage on ageing platforms. Recommendations for mandatory third-party waste audit programmes and platform waste minimisation targets are proposed. Keywords: offshore platform waste, MARPOL, produced water, Nigerian waters, marine pollution