PERFORMANCE EVALUTION OF LARGE SEWAGE TREATMENT PLANTS IN NORTHERN INDIA

Abstract

The fate of four phthalate esters diethyl phthalate (DEP), di-n-butyl phthalate (DBP), butyl benzyl phthalate (BBP), bis (2-ethylhexyl) phthalate (DEHP) were investigated as phthalate passed through five full scale sequencing batch reactor (SBR) method based wastewater treatment plant (WWTP). The removal of DEP through degradation is 65-98%, up to 93% of DBP, up to 90% for DEHP is recorded. Removal through waste sludge is nearly 14% for various phthalate esters. Risk of phthalate esters from WWTPs effluent was found to know the level of harm to human. It is determined through the risk quotient (RQ). If RQ >1 then risk is present in uptake drinking water. In this study DEHP has RQ >1 and other two phthalate esters DEP, DBP have RQ <1. BBP was not detect in SBR influent and effluent. Exposure concentration to adult was determined to find the accumulation of phthalate esters in human body through drinking water. Removal percentage of phthalate esters by treatment was compared with the removal fraction of physicochemical parameters of WWTP. That helps in establish a relationship between these parameters with phthalate esters concentration. SBR method is significant in reduction of DEP and DBP through degradation process and adsorption process. DEHP require more hydraulic retention time to remove it through WWTP.