Use of moringa oleifera seed extracts as alternative natural material for water purification

Abstract

This research paper investigated the effectiveness of the use of different Moringa oleifera coagulants for the removal of turbidity, bacteria, and natural organic matter (NOM) from natural surface water using laboratory experiment. In the laboratory study water sample with turbidity of 64NTU was analysed and treated with the three coagulants produced from the Moringa oleifera seed namely: the shell- blended (without oil extraction) seed powder, de-oiled seed powder and the purified protein (polymer) powder. Jar test was conducted to determine the optimum dosages of the coagulant needed in the treatment of raw surface water using the three different coagulants as named above. The concentration of the dose selected for the jar tests were; 30mg/l, 50mg/l, 70mg/l, 90mg/l, 100mg/l and 120mg/l for all three coagulants. The optimum dosages for the shell- blended, de-oiled seed powder and the purified protein powder were found to be 100mg/l, 100mg/l and 90mg/l respectively. After treatment with the optimum coagulant dosage, the water samples were analysed for different physiochemical parameters such as the pH, total solids, turbidity, alkalinity, MPN and SPC. Protein powder had the highest turbidity removal efficiency with a percentage turbidity removal of 92.3% followed by de-oiled powder with a percentage turbidity removal of 83.25% and shell blended powder with a percentage turbidity removal of 75.68% at optimal dosage. The total coliform present in the raw water sample which was measured quantitatively was beyond the W.H.O limit. All three coagulants were able to reduce the total coliforms to a level which conforms to the standard set by the W.H.O. Protein polymer powder had the highest reduction efficiency at optimal dosage followed by the de-oiled powder which was then followed by shell- blended coagulant powder. This study has shown that Moringa oleifera seeds are highly effective in the reduction of the turbidity and faecal coliforms of turbid surface water. In the overall investigations, the results obtained were seen to be comparable to inorganic coagulants of alum and ferric chloride. The use of Moringa oleifera coagulant in combination with alum and ferric chloride showed that reduced usage of inorganic salts to an average of 60% could be achieved. Bactericidal activity seemed to be evident through analysis of E.coli viability in the water and sludge treated by the Moringa oleifera coagulant. Moringa oleifera seed extract was found to have no significant effect on pH or alkalinity of the water. The residual turbidities measured during most of the test runs were seen to satisfy Guideline for Drinking Water Supplies. Findings of this research paper lend support to earlier works recommending the use of Moringa oleifera as alternative natural material for water treatment.