Fate of four Different Classes of Chemicals Under Aerobic and Anaerobic Conditions in Biological Wastewater Treatment

Abstract

The removal mechanisms and extent of degradation of 28 chemicals (triclosan, fifteen polycyclic aromatic hydrocarbons, four estrogens, and eight polybrominated diphenyl ether congeners) in different biological treatment systems [activated sludge, up-flow anaerobic sludge blanket reactor (UASB) and waste stabilization pond (WSP)] was investigated to provide insights into the limits of engineered biological treatment systems. This was done through degradation experiments with inhibition and abiotic controls in static reactors under aerobic and anaaerobic conditions. Estrogens showed higher first order degradation rates (0.1129 h−1) under aerobic conditions with activated sludge inocula followed by low molecular weight (LMW) PAHs (0.0171 h−1), triclosan (0.0072 h−1), middle (MMW) (0.0054 h−1) and high molecular weight PAHs (HMW) (0.0033 h−1). The same trend was observed under aerobic conditions with a facultative inoculum from a WSP, although at a much slower rate. Biodegradation was the major removal mechanism for these chemicals in the activated sludge and WSP WWTPs surveyed. Photodegradation of these chemicals was also observed and varied across the group of chemicals (estrogens (light rate = 0.4296 d−1; dark = 0.3900 d−1) degraded faster under light conditions while reverse was the case for triclosan (light rate = 0.0566 d−1; dark = 0.1752 d−1). Additionally, all the chemicals were resistant to anaaerobic degradation with UASB sludge, which implies that their removal in the UASB of the surveyed WWTP was most likely via sorption onto solids. Importantly, the first order degradation rate determined in this study was used to estimate predicted effluent concentrations (PECs). The PECs showed good agreement with the measured effluent concentrations from a previous study for these treatment systems.

Microbial Debromination of Polybrominated Diphenyl Ethers by Dehalococcoides-Containing Enrichment Culture

“…This enhancement greatly shortened the debromination period and achieved more extensive debromination of higher BDE-183. The dominantly produced tri-BDEs are less toxic and tend to be more readily degraded by microorganisms in the environment ( ATSDR, 2017 ; Komolafe et al, 2021 ), thus likely reducing the public health risks. Generally, the supplement of the auxiliary substrates of more readily utilized electron acceptors, such as other organohalide pollutants (e.g., trichloroethene) or priming organic nutrients (e.g., lactate) have shown an obvious enhancement of BDE debromination in lab-scale studies ( Robrock et al, 2008 ; Lee and He, 2010 ; Ding et al, 2013 ).…”

Effect of Carbamazepine, Ibuprofen, Triclosan and Sulfamethoxazole on Anaerobic Bioreactor Performance: Combining Cell Damage, Ecotoxicity and Chemical Information

“…Conventional WWTP are not designed for the optimal removal of CEC. Recently, studies in the literature analyzed PPCPs in WWTP, based on mass balances and considered their biological or abiotic degradation, presence in liquid phase effluents, or sorption in the sludge sewage [12,13], even focusing on AD of sewage sludge [14]. The analysis of sludge samples from several WWTPs showed that nearly 20 PPCPs can be detected in sewage sludge in concentrations up to 100 ng/g.…”