Abstract

Recently, attention has been focused on the activities of plant extracts that have been researched as green alternatives to chemical substances in treating turbid and toxic industrial wastewater. The use of Jatropha curcas as a bio-coagulant and metal-chelating agent for treating tannery wastewater has been scarcely exploited and documented. Effluent streams from tanneries are laden with pollutants ranging from suspended and dissolved solids to heavy metals. This study used protein extract from Jatropha curcas seed cake to treat tannery wastewater. 1 M sodium chloride solution was prepared, and protein was extracted from Jatropha curcas seed cake for active coagulation and metal complexing. The effect of treatment on pH, conductivity, and total dissolved solids (TDS) of the wastewater was obtained for coagulant dosages from 10 to 50 ml/L for a retention time of 24 hr. The pH of the treated effluent shifted towards alkalinity while conductivity and TDS increased as coagulant dosage increased. The pH, conductivity and TDS of the treated effluent were within acceptable limits by NESREA and WHO. The reduction in concentration of selected metals – chromium, iron, magnesium, calcium, sodium, and iron- was obtained and analysed via atomic absorption spectroscopy. Jatropha curcas seed cake extract proved to be an active bio-coagulant and metal chelator for treating tannery wastewater