Monitoring of chloro-organic compounds from Indian paper mills wastewater

Abstract

Untreated and treated wastewater samples were collected from eight paper mills from different parts of India for the monitoring studies. Six categories of chlorophenolic compounds (chlorophenols (CP), chlorocatechols (CC), chloroguaiacols (CG), chlorosyringol (CS), chlorosyringaldehyde (CSA), and chlorovanillin (CV)) and four cRFA compounds, i.e. chlorodehydroabietic acid (CDAA), 12,14-dichlorodehydroabietic acid (DCDAA), 12,13-dichlorostearic acid (DCSA), and 9,10,12,13-tetrachlorostearic acid (TCSA) were detected in the paper mills wastewater. 2,3,7,8- tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) was also detected in the wastewater samples of two mills. The concentration range of chlorophenolics, cRFA, and 2,3,7,8-TCDD detected in untreated wastewater of pulp and paper mills was 12-239 μg L-1, 37-157 μg L-1, and 0-5.4 ng L-1, respectively. Among CP, 2,4-dichlorophenol, 2,5-dichlorophenol, and 2,4,5- trichlorophenols are the dominating compounds detected in paper mill wastewaters. It was observed that the removal of chloro-organics was low by activated sludge process (ASP) and the treated wastewater discharges from the paper mills still contained significant amounts of toxic compounds which are harmful for the receiving aquatic bodies.