Laboratory evaluation of a water-treatment sequence using Moringa oleifera seed coagulant

Abstract

A water extract of Moringa. oleifera seed was applied to a treatment sequence comprising coagulation-flocculation-sedimentation-sand filtration. Model waters (kaolinite suspensions) of turbidities 10, 100, 300 and 700 NTU were prepared. For the 10 NTU water, the optimum dose was only evident when sand filtration was incorporated into the treatment sequence. For the higher water turbidities tested, a relatively broad optimum dose range exists post filtration. After filter ripening, the filtrate turbidities obtained for the 300 and 700 NTU raw water turbidities were 1 NTU and 3 NTU respectively. Headloss development was gradual giving relatively long filter runs.