Author(s)

S. M. Sajidu, E. M. T. Henry, G. Kwamdera & L. Mataka

Abstract

There is increasing interest in developing low cost water and wastewater treatment processes particularly in poor countries. The use of natural coagulants such as the Moringa polyelectrolytes to replace expensive imported synthetic coagulants is particularly appropriate for agro-based developing countries such as Malawi because local production of these coagulants will also contribute to the rural and national economy. There is also widespread recognition that the presence of heavy metals, such as cadmium, lead and iron, in water is hazardous to the environment and human health and their discharge into surface waters is a concern worldwide. This study was conducted to investigate the potential of Moringa Oleifera polelectrolytes for treatment of wastewater contaminated with heavy metals. The potential of Moringa Oleifera whole seed kernels and ram press cakes, in removing lead, iron, and cadmium ions from synthetic contaminated water was investigated at initial metal ion concentrations of 5.00 and 7.00 ppm by means of jar tests. Metal ion removal was observed ranging from 70.86 ± 2.22% to 89.40 ± 0.00% for lead, 66.33 ± 3.38% to 92.14 ± 0.00 % for iron and 44.95 ± 3.95% to 47.73 ± 6.38 % for cadmium. Further experiments on optimization of the reaction conditions such as pH and coagulant dosage, method of extraction of polyelectrolytes and elucidation of the nature of interactions are being carried out. Earlier work by the same group has shown that Moringa Oliefera ram press cake polyelectrolytes reduce wastewater turbidity by over 99% and reduce faecal coliform counts by 89% at an optimal dosage of 120 mg/L without affecting pH or significantly increasing BOD. This paper is the first report of heavy metal ion removal by moringa polyelectrolytes. Keywords: Malawi, polyelectrolytes, Moringa Oliefera, whole seed kernels, ram press cakes, lead, iron, cadmium, jar tests, wastewater, trace and heavy metals, coagulant.

Keywords

Malawi, polyelectrolytes, Moringa Oliefera, whole seed kernels, rampress cakes, lead, iron, cadmium, jar tests, wastewater, trace and heavy metals,coagulant.