Efficient and sustainable treatment of industrial wastewater using a tannin-based polymer

Abstract

ABSTRACT Paint, tannery and textile manufacturing wastewaters contain highly toxic and organic biorefractory compounds and have adverse effects on human health. These effluents require efficient and environment friendly solutions before being discharged. Jar-test experiments are conducted in order to assess the efficiency of a tannin-based polymer (TBP) on the treatment of these industrial wastewaters. The results indicate that TBP is more effective than classical coagulant iron chloride. Coagulation flocculation involving TBP does not require any coagulation pH adjustment, reduces more than 96% of colour and achieves 60, 65 and 87% of COD removal from textile, tannery and paint wastewater respectively. Compared to iron chloride, TBP produces the least amount of sludge for a given amount of COD and colour removed. It produces 28 to 60 % less volume of sludge than FeCl3, and generates a good settling sludge with lower values of SVI (31- 80 ml g−1). Furthermore, TBP allows 4 to 6.5% of water recovery more than FeCl3. Utilisation of such polymer represents an important progress in sustainable environmental technology as it is a renewable resource and allows a lower pollution load, a good settling sludge and an adequate water recovery.