OJO, Otti Oise

This study assessed the dual-scale techno-economic feasibility of using Moringa oleifera as a natural coagulant–flocculant for greywater treatment. The study aimed to evaluate the dual-scale techno-economic feasibility of using locally sourced coagulants for coagulation-flocculation treatment of greywater, with a focus on treatment efficiency, costeffectiveness and possible reuse. The study involved the collection of greywater from a commercial kitchen and its treatment in a fabricated coagulation–flocculation water treatment prototype using locally sourced materials. Moringa oleifera seeds were processed into powder and applied at optimized dosages in operational use of the prototype for greywater treament. Physicochemical parameters including pH, electrical conductivity, turbidity, total dissolved solids (TDS), total suspended solids (TSS), chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were analyzed before and after treatment. A techno-economic analysis compared the experimental moringa-based system with a conventional alumbased system in terms of capital expenditure (CAPEX), operating expenditure (OPEX), energy consumption, sludge management and payback period. The results of this study revealed substantial reductions in key pollutants: turbidity decreased from 8.4 NTU to 3.7 NTU, TSS from 22.4 mg/L to 8.7 mg/L, COD from 800.4 mg/L to 310.6 mg/L, and BOD from 101.3 mg/L to 79.4 mg/L, while colour reduced from 10.4 Pt.Co to 5.3 Pt.Co. However, TDS and EC values decresed from 2577 mg/L to 2554 mg/L and 5153 S/cm to 5107 S/cm respectively but remained above permissible limits, indicating a need for further treatment. The techno-economic analysis showed that the moringa-based system required lower CAPEX (₦ 2.2 million vs ₦ 3.0 million), reduced OPEX (₦ 540,000/yr vs ₦ 820,000/yr), and achieved a faster payback (3.8 years vs 6.5 years), yielding a return on investment of 28% compared to 15% for alum. The study concluded that Moringa oleifera is an effective, eco-friendly and cost-efficient coagulant suitable for decentralized greywater treatment. It is recommended that further optimization of dosage, integration with biological post-treatment and pilot-scale community deployment be pursued to enhance reuse potential and policy adoption.