The use of Moringa oleifera seed as a natural coagulant for wastewater treatment and heavy metals removal

Abstract

Moringa oleifera (MO) is a multipurpose tree with considerable potential and its cultivation is currently being actively promoted in many developing countries. Seeds of this tropical tree contain water-soluble, positively charged proteins that act as an effective coagulant for water and wastewater treatment. Based on this, water quality of “Sungai baluk” river was examined before and after the treatment using MO seed. MO seed exhibited high efficiency in the reduction and prevention of the bacterial growth in both wastewater and “Sungai baluk” river samples. The turbidity was removed up to 85–94% and dissolved oxygen (DO) was improved from 2.58 ± 0.01 to 4.00 ± 0.00 mg/L. The chemical oxygen demand (COD) and biological oxygen demand (BOD) were increased after the treatment from 99.5 ± 0.71 to 164.0 ± 2.83 mg/L for COD and from 48.00 ± 0.42 to 76.65 ± 2.33 mg/L for BOD, respectively. Nevertheless, there was no significant alteration of pH, conductivity, salinity and total dissolved solid after the treatment. Heavy metals such as Fe were fully eliminated, whereas Cu and Cd were successfully removed by up to 98%. The reduction of Pb was also achieved by up to 78.1%. Overall, 1% of MO seed cake was enough to remove heavy metals from the water samples. This preliminary laboratory result confirms the great potential of MO seed in wastewater treatment applications.