Characterisation of Industrial Effluents from a Beverage Manufacturing Plant in Lagos State and Assessment of Treatment Options

Beverage manufacturing plants in Lagos State, South West Nigeria, generate high-strength effluents characterised by elevated biochemical oxygen demand, suspended solids, and residual sugars, which pose risks to the Lagos Lagoon receiving environment. This study characterises the effluent from a medium-scale beverage facility in Ikeja Industrial Estate over a six-month sampling period and assesses the efficiency of coagulation-flocculation and biological treatment as remediation options. Composite effluent samples were collected weekly and analysed for pH, biochemical oxygen demand, chemical oxygen demand, total suspended solids, total dissolved solids, turbidity, dissolved oxygen, and total coliform counts. Coagulation trials were conducted using alum, polyaluminium chloride, and ferric chloride at doses of 50 to 400 mg/L with pH adjustment between 5.5 and 8.0. A bench-scale activated sludge reactor was operated over 30 days to assess biological treatment performance. Coagulation with polyaluminium chloride at 200 mg/L and pH 7.5 achieved the highest suspended solids removal (91.4%) and turbidity reduction (94.2%). Biological treatment reduced biochemical oxygen demand from 1,840 mg/L to 68 mg/L, a 96.3% reduction, satisfying National Environmental Standards and Regulations Enforcement Agency effluent limits. Combined coagulation followed by biological treatment is recommended for implementation at the facility. Keywords: beverage effluent, coagulation-flocculation, biological treatment, BOD, Lagos