Abstract

Moringa oleifera plant is unique due to its coagulation effect on turbid water. However, the extent to which the seed’s powder coagulant changes the physico-chemical characteristics of treated water has not been discussed in previous studies. In addition, there are limited data and information on the optimum concentration of M. oleifera seed powder coagulant and the nature of the sludge that forms after the treatment of water. The aim of this study is to examine the extent to which M. oleifera seed powder can be used as a coagulant in treating different types of turbid waters and how it changes the physico-chemical characteristics of treated water.  Samples of turbid water were subjected to various dosages of dry M. oleifera seed powder concentrations to determine the degree of clarification, changes in physico-chemical characteristics of water and the proportion of sludge formed after coagulation process. The results showed that M. oleifera seed powder leads to reduction of water turbidity from 461 NTU to about 15 NTU within 45 min. Significant clarification of turbid water occurred at the mean optimum concentration of M. oleifera seed powder coagulant (0.20 g/l) and maximum optimum concentration of 0.50 g/l. The mean water turbidity reduction efficiency was 64% with the maximum efficiency of 95%. Increasing coagulant concentration above 0.50 g/l led to an increase in water turbidity, electrical conductivity, salinity and total dissolved solids (TDS). The sludge formed after water treatment was found to be equivalent to 10% of the total volume of treated water.  There are also significant differences in the effectiveness of coagulant derived from various provenances of M. oleifera found in Eastern and Coastal regions of Kenya in terms of turbidity reduction.

Key words: Moringa oleifera, turbidity, water treatment, coagulation, physico-chemical parameters.