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In the present work, wastewater treatment plants and collection systems from Nagpur, Central India were studied for frequently occurring endocrine disrupting chemicals. All the EDCs, such as bisphenol A, butylparaben, and diethyl phthalate were present in all the collected samples with a detection frequency of 100%. Laboratory analysis revealed high bisphenol A, butylparaben, and diethyl phthalate levels, with mean concentrations of 79.10, 4.12, and 2.25 μg/L, respectively, in influent samples and 33.20, 1.62, and 0.77 μg/L, respectively, in the effluent wastewater. The distribution of the emergent pollutants among the sampling locations was found to be consistent with the physicochemical characteristics of wastewater, according to the component analysis, and the sites with the highest levels of contamination were also identified. Finally, an ecological risk assessment was carried out for aquatic biota in terms of risk quotients. The risk quotients for the target chemicals in effluent wastewater suggested a minimal impact, except for the target insect Chrironomus riparius, which had a risk quotient value of 33.20 for bisphenol A. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes (AOPs) for the degradation of recalcitrant wastewater are of interest due to field application potential. We attempted the treatment of caprolactam (CL) wastewater which is highly acidic (pH 3.1) with low biodegradability index, using AOPs viz. electrochemical oxidation (EO) and ozonation. EO experiments under recirculation batch mode (20 mL min−1) in a three-dimensional carbon bed reactor confirmed 18% chemical oxygen demand (COD) reduction. The first order rate constant for the EO of CL wastewater was estimated as 1.38 ± 0.15 × 10−2 min−1. The apparent Faradic efficiency and specific energy consumption were found to be 9.4% and 2.75 kWh kg−1 COD, respectively. Similarly, 27% COD and 26% total organic carbon were removed during 4-h ozonation. Various organic compounds present in the raw and ozone treated effluent have been identified using GC-MS; while many degraded partially, CL persisted even in 10-h reacted samples. Both EO and ozonation methods are insufficient for the degradation of highly non-biodegradable complex wastewater. [ABSTRACT FROM AUTHOR]

Industrial effluent treatment plants (ETPs) are very important in protecting the environment and different life forms from harmful industrial waste. Hence, the efficiency of ETPs must be regularly monitored, particularly after major repair or replacement work. Present study evaluated the performance of an ETP over a period of 4 months, during which aeration tank (T1) of the activated sludge unit was replaced with a new one (T2). System had to be maintained operational during this transition, which warranted close monitoring of the system performance due to the daily load of hazardous industrial wastewater. Analysis showed that the raw wastewater was highly variable in composition and contained many hazardous organic and inorganic pollutants, such as heavy metals, bisphenol A and cyanoacetylurea. It showed significant toxicity against HepG2 cells in vitro. However, the ETP was found to successfully treat and detoxify the wastewater. Denaturing gradient gel electrophoresis (DGGE) analysis showed large temporal fluctuations in the ETP microbial community, which is consistent with the variable composition of wastewater. It indicated that functional stability of the ETP was not associated with stability of the microbial community, probably due to high microbial biodiversity and consequently high functional redundancy. In conclusion, the CETP showed consistent level of detoxification and microbial community dynamics after switching to T2, indicating successful development, acclimatization and commissioning of T2.