In recent years, plant-derived coagulants have been proposed as alternatives to traditionally used chemical coagulants, such as aluminum sulfate (alum) and ferric chloride. Moringa oleifera (M. oleifera) is a tree that is cultivated in many regions of the world (Central America and the Caribbean, parts of South America, Africa, South and Southeast Asia, parts of Oceania), including regions of water scarcity. M. oleifera’s seeds can be processed to extract a coagulant that has been demonstrated to be effective in removing suspended materials from various water types of practical importance. The goal of this thesis is to explore the feasibility of using M. oleifera for coagulation as pretreatment for ultrafiltration (UF). The present work employs two types of water (high and low turbidity) and uses alum as baseline comparison.The study first compared coagulation performance of M. oleifera with that of alum, identified optimal coagulant doses for each, and subsequently used M. oleifera-derived coagulant to treat feed water for UF. Permeate flux was measured before and after membrane filtration a well as after simulated hydraulic cleaning of the membrane. Flux recovery ratio (FRR) was used as a quantitative metric of membrane cleaning efficiency, while hydraulic resistances (of the membrane and of the fouling layer) were used to characterize the extent of fouling. Residual total organic carbon (TOC) was measured after coagulation-flocculation- settling treatment with M. oleifera and after subjecting this water to UF. M. oleifera was found to be comparable to alum in terms of turbidity reduction for high turbidity water but was more effective than alum in reducing turbidity in low turbidity water. Water treated with alum initially fouled the UF membrane quickly and tapered off into gradual fouling; in contrast, M. oleifera gradually fouled the UF membrane throughout filtration. For low turbidity applications, initial findings suggest that, while a higher FRR can be achieved with M. oleifera than alum, there is no significant benefit to fouling achieved by the addition of a coagulant. However, the presence of organics, regardless of origin, seem to result in fouling that is more difficult to address with hydraulic cleaning. UF effectively removed residual organics introduced by M. oleifera for low turbidity water, but insufficient TOC removal was observed for the higher doses required to treat high turbidity water during CFS. The results suggest that for low turbidity feeds, coagulation with M. oleifera is a viable pretreatment for downstream UF.
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