Physico-Chemical Treatment of a Wastewater Collector Loaded with Metals and Suspension Material by The Solution of Raw Carica papaya Latex

Abstract

The papaya (Carica papaya), of the family Caricaceae, is a tree-like tropical plant, native to Central and South America. Papaya cultivation extends to all warm and humid countries. The present study consists in using the solution of raw Carica papaya latex (SLCP) cultivated in Benin as a natural biodegradable flocculant in a physico-chemical process to treat liquid discharges loaded with metals including iron, copper, zinc, and manganese; and suspended matter, and also to test its efficiency against other products commonly used in wastewater treatment. The tests were carried out on water samples from the wastewater collector that runs through the Agla district in Cotonou. The comparative study with a commonly used flocculant, aluminium sulphate, showed outstanding competitiveness with a high flocculation power for the solution of Carica papaya raw latex. In six water samples from the collector with average concentrations of iron, copper, zinc and manganese of 18.20 mg/L ; 2.50mg/L ; 3.80 mg/L and 3.70 mg/L respectively, the percentages of metal removal exceeded 90% for iron and manganese and around 85% for copper and zinc with the combination FeCl3 + SLCP. The NaOH + SLCP combination showed a very significant effect on the removal of metals (96% reduction) and suspended matter.