Use of extract of moringa seeds as coagulant agent in treatment of water supply and wastewater

Abstract

The objective of this work was to evaluate the efficiency of the extract of moringa (Moringa oleifera) seeds when used as a coagulant agent, in removal of turbidity and coliform in domestic sewage, pig wastewater and water to be used for public supply. To evaluate the effect of coagulant on each type of water, tests were performed using the Jar-test apparatus, and was evaluated the effects of the concentrations of 0.02; 0.04; 0.06; 0.1; 0.2; 0.3; 0.4; 0.6; 0.8 and 1.2 g of powdered seeds per liter of analyzed water. Turbidity was measured in suspensions after 2 and 24 h and counting of organisms of the group total coliforms (TC) and fecal or thermotolerants coliforms (FC) after 24 h of application and mixing of the coagulant. Mathematical equations were fitted by regression, relating the concentration of the extract of moringa seeds in water samples with turbidity. It was found that in the water to be used for public supply, the concentration of 0.4 g L-1 of moringa seeds to a sedimentation time of 2 h presented the best turbidity removal (98%). In equal sedimentation time, the average removal of turbidity in the domestic wastewater was 22.3%. On a larger sedimentation time (24 h), the average removal is increased to 35.3%. The addition of extract of moringa seeds not presented turbidity removal of pig wastewater. With regard to the removal of TC and FC, the concentration of 0.2 g L-1 of seeds was the most suitable for water to be used for public supply, obtained 90% of FC removal. In the case of domestic sewage, the best concentration was 0.04 g L-1 of seeds, has been obtained removals of 95.6 and 94.3%, respectively, and in pig wastewater, the best concentration was 0.8 g L-1 of seeds, which presented removals of 96.5 and 94.8%, respectively.