Fate and impact of phthalates in activated sludge treated municipal wastewater on the water bodies in the Eastern Cape, South Africa

The concentration and fates of six priority phthalate esters (PAEs); dimethyl phthalate (DMA), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), benzyl butyl phthalate (BBP), di (2-ethyl hexyl) phthalate (DEHP), and di-n-octyl phthalate (DOP) in wastewaters from the wastewater treatment plants (WWTPs) which adopted the activated sludge technology in the Amathole Municipality, Eastern Cape, South Africa were investigated. The six PAEs were detected in all the influents and in almost all the WWTP effluent of which DBP was the most abundant in the influent followed by DEHP. Influent concentration of DBP in the three WWTPs ranged between 2.7 and 2488 mu gL(-1) and the average effluent concentration was 4.90 -8.88 mu gL(-1). On average, the concentration of PAEs in WWTP effluents were higher than PAEs in the upstream and downstream of the discharging point suggesting PAE impact on the receiving water. The concentrations detected in the sludge of which DEHP and DBP were more pervasive ranged between 130 and 1094 mu g/g dry weight. The average removal capacity; 27.3-99.5% suggested more adsorption on settling particles and sludge than biodegradation as high significant correlation was found between PAEs removal, total suspended solid and turbidity. Removal of high molecular weight and high octanol-water partition coefficient (logK(ow)) PAEs through adsorption was found to be significantly high. It could be concluded that the release of PAEs into the sludge, and the amount in the final effluent which were found to exceed the acceptable levels allowed internationally, raises safety concern for both aquatic and human's health. (C) 2018 Elsevier Ltd. All rights reserved.