Assessing the Effectiveness of Low-Cost Coagulant Alternatives Derived from Moringa oleifera in Rural Water Treatment in North East Nigeria

This study assesses the effectiveness of Moringa oleifera seed extract as a low-cost natural coagulant for treating turbid surface water in rural communities of North East Nigeria, addressing the research gap on optimised application conditions and performance reliability under field-representative conditions in the Sahel region. Moringa oleifera coagulation represents a promising appropriate technology for rural water treatment where chemical coagulants are unaffordable or unavailable, but published studies have predominantly used laboratory-optimised conditions that may not reflect the variable turbidities and water temperatures encountered in practice. Surface water samples from three rivers in Adamawa and Gombe States were used as representative raw water sources, with natural turbidity varied between 50 and 800 nephelometric turbidity units. Jar test experiments systematically evaluated the effects of Moringa extract concentration, pH, rapid mixing intensity, slow mixing duration, and settling time on turbidity removal and residual protein content using Box-Behnken response surface design. Bacteriological reduction was assessed using membrane filtration for E. coli. Optimised conditions identified from the response surface analysis were validated in a pilot-scale slow sand filter column fed with Moringa-coagulated water. Results show that Moringa extract achieves turbidity removal above 90 percent for initial turbidities between 100 and 600 NTU under optimised conditions, with maximum effectiveness at pH 7 to 8 and extract dose of 40 to 80 milligrams per litre. E. coli reduction of 1.5 to 2.0 log units is achieved by coagulation followed by slow sand filtration. Keywords: Moringa oleifera, natural coagulant, water treatment, turbidity removal, North East Nigeria.