Effect of salt solutions on coagulation performance of Moringa stenopetala and Maerua subcordata for turbid water treatment

The objective of this study is to improve the turbidity removal efficiency of Moringa stenopetala (Baker f.) Cufod and Maerua subcordata (Gilg.) DeWolf using various salt solutions. For this purpose, different coagulant solutions were obtained from solutions of NaCl, NH4Cl and KNO3 in different concentrations (0.01, 0.1, 0.5, 1, and 1.5 M) and deionized water. The coagulation activity of the extracts was measured in synthetic water made of a kaolin clay suspension. The turbidity removal efficiency was tested using spectrophotometric-based assays. The result of the study indicated that at the optimum dose of 2 mu g/mL, 4 mu g/mL using 0.5 and 1.5 M of NaCl and NH4Cl salts respectively. Extracts from M. stenopetala coagulated highly turbid water within 0.5 to 1 h. However, M. subcordata extracted with the same salt types showed lower turbidity removal after 0.5 to 1 h settling time. With increasing contact time especially after 3 h, both extracts of salts and deionized water of both the plant coagulants performed as efficient as alum achieving nearly 95% reduction of highly turbid water. Extraction of natural coagulants using salt solutions improve the coagulation efficiency of the plant species. With further optimization, coagulants from M. stenopetala and M. subcordata can be used on wider scale water treatment technologies.