Fate and ecological risk assessment of phthalates in wastewater treatment plants

With the rapid increase in plastics use worldwide, phthalates (PAEs) as an endocrine disruptor, have been receiving attention. It is necessary to investigate the pivotal considerations affecting the degradation of PAEs and the ecological risk assessment in wastewater treatment plants. The presence and spatial distribution patterns of 16 PAEs across three wastewater treatment plants (WWTPs) in northern China were studied by collecting wastewater samples, and by comparing the mechanism of action of AAO and oxidation ditch process on the removal efficiency of long and short chain PAEs, we fill the gap in the study of comprehensive assessment and process-specific removal effect of multiple PAEs. The influent concentration of PAEs and the treatment process were the pivotal considerations in the primary and secondary treatments, respectively. In the primary treatment stage, long-chain PAEs were more readily removed compared to short-chain PAEs. Conversely, during the secondary treatment, short-chain PAEs were removed more effectively than long-chain PAEs, independent of the specific treatment process. Long-chain PAEs were more easily removed during the AAO processes. Furthermore, the ecological risk assessment of the effluent was conducted at each stage of the three WWTPs. The ecological risk assessment results of the three WWTPs for fish and Daphnia showed no risk, while that for green algae showed a low risk. These findings can be used as a model for controlling PAEs and provide important information on the occurrence and distribution of PAEs in WWTP and their ecological risks of effluents.