The threat of PPCPs from WWTP and solutions of advanced reduction coupled treatment processes with pilot-scale

Abstract

Pharmaceuticals and personal care products (PPCPs) in wastewater treatment plants (WWTP) pose potential threats to the receiving aquatic ecosystems. It is urgent to assess the risk and actively seek reliable solutions. In this study, 14 representative pharmaceuticals were selected as target pollutants. A combination of pilot-scale advanced oxidation processes (AOPs) and advanced reduction processes (ARPs) was evaluated, alongside field sampling of a conventional WWTP and its associated receiving river. The conventional WWTP exhibited limited removal efficiency for the target compounds, achieving an average elimination rate of only 65.51 %. This insufficient removal resulted in ecological and human health risks, particularly due to the persistence of carbamazepine, quinolones, and nonsteroidal anti-inflammatory drugs. Moreover, the residual cytotoxicity of the effluent was more persistent and difficult to eliminate than the target pollutants. The removal rates of PPCPs by autotrophic denitrification and heterotrophic denitrification in existing deep treatments were 27.56 % and 10.14 %, respectively. In contrast, advanced oxidation processes (AOP) and advanced reduction processes (ARP) had greater removal rates over the concentration of target pollutants (98.93 ± 0.66 %, 2.90 ± 0.02 times), risks (98.52 ± 1.11 %, 2.50 ± 0.03 times), cytotoxicity (68.36 ± 21.37 %, 5.03 ± 1.57 times), and genotoxicity (93.06 ± 13.14 %, 1.27 ± 0.18 times). In particular, the addition of ARP enhanced the biodegradation capacity to pollutants and increased cytotoxicity (70.95 % average rise) and genotoxicity (16.02 % average rise) removal rate in the whole-water than AOP. These findings enriched our knowledge of PPCP hazards in WWTP with its receiving river and provided a technological approach for comprehensive control of emerging contaminants, risks, and toxicity.