The effects of the seed powder of moringa oleifera lam on the quality of wastewater used for vegetable farming in the Kumasi Metropolis

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Moringa oleifera Lam (MO) is a pan tropical, multipurpose tree whose seeds contains high quality edible oil (up to 40% by weight) and water soluble proteins that act as effective coagulants for water and wastewater treatment. Laboratory jar test procedures have been used for coagulation studies on experimental runs using actual wastewater from urban vegetable farms in Kumasi. Water extracts of Moringa oleifera seeds were applied to a wastewater treatment sequence comprising coagulation–flocculation–sedimentation. The results indicate a significant (p<0.05) reduction in turbidity. It revealed that 20mL of 4% (w/v) and 5 % (w/v) MO seed coagulant were very effective in removing turbidity of 250-350NTU to 10 NTU for 1L of raw water. In addition turbidities of 250-300 NTU were lowered to 10-50NTU at 80-100ml of 1.5, 2 and 3 % (w/v). MO also achieved an overall percentage turbidity reduction of 70% for low turbid water (<50NTU), 80% for medium turbid water (50-150NTU) and 95% high turbid water (>150NTU) at 3%w/v and 100mL of MO using 1L of raw water. It was also observed that pH, conductivity, and TDS of the wastewater were not affected by the MO seed powder. Nitrate, chlorine and sulphate were not influenced by the MO except phosphate which recorded a slight increase. Natural alkalinity and total hardness of the raw water remained unchanged after treatment with the MO seed powder. From the results, MO concentrations of 1.5 - 5% (w/v) also reduced faecal coliform levels of the wastewater by 97.88%-99.96% (log 1.71-3.82) within one hour. These studies have shown that the MO seeds are highly effective in the treatment of wastewater from shallow wells and ponds from urban vegetable farms.
A thesis submitted to the Department of Chemistry, College of Science, Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements for the degree of Master of Science (Environmental Chemistry).