EFFICIENCY OF NEEM LEAF EXTRACT AS A COAGULANT IN THE TREATMENT OF ABATTOIR WASTEWATER

ABSTRACT This study investigated the efficiency of Azadirachta indica (Neem) leaves as a natural coagulant for the treatment of abattoir wastewater, with the aim of providing a low-cost and environmentally-friendly alternative to conventional chemical coagulants. The raw wastewater was collected from abattoir at Oke-Gada, Ede, and its initial physicochemical and bacteriological characteristics were determined. Neem leaves were dried, ground, and applied at varying dosages of 2.5 g/L, 5.0 g/L, 7.5 g/L, and 10 g/L, while an untreated sample served as control. Coagulation was performed following standard APHA procedures, and the clarified samples were analyzed for pH, turbidity, colour, TSS, TDS, BOD, COD, chloride, alkalinity, and microbial load. XRF analysis of the Neem powder showed high contents of SiO2, CaO, MgO, K2O, and P2O3, confirming the presence of metal oxides responsible for charge neutralization and floc formation. The untreated wastewater exhibited very high pollutant levels, including BOD of 391.20 mg/L, COD of 1928.63 mg/L, low DO of 1.20 mg/L, and extremely high turbidity and colour, exceeding FEPA discharge limits. Treatment with Neem leaf powder significantly improved water quality, with the optimum performance recorded at 5 g/L dosage, which produced notable reductions in BOD (15.18%), COD (32.78%), TSS (35.87%), and chloride (22.21%), alongside improved pH, lower turbidity, and increased dissolved oxygen. Bacteriological analysis showed over 95% reduction in E. coli and more than 99% reduction in total bacterial count, indicating strong antimicrobial effects. Although BOD and COD after treatment remained slightly above FEPA limits, other parameters fell within acceptable ranges. The findings therefore demonstrate that Neem leaves are an effective bio-coagulant capable of improving physico-chemical and microbiological qualities of abattoir wastewater, offering a sustainable, locally available, and cost-effective option for pre-treatment in regions lacking advanced treatment facilities.