Efficient PPCPs removal from wastewaters via a novel A/O-MBBR system: Transition towards circular economy in the water sector.

As industrial and agricultural production depends on water supply, it is crucial for economic development. The available freshwater reserves on Earth are insufficient to meet humanity's growing demands. This study establishes a three-stage anoxic/oxic (A/O)-moving bed biofilm reactor (MBBR) system. The study evaluated the wastewater purification capacity of the system in summer and winter, examined the system's removal efficiency of 10 pharmaceuticals and personal care products (PPCPs) from the water, and analyzed the composition of microbial communities. Results indicate that the system effectively removes pollutants and PPCPs, with the aerobic tanks in the first two A/O stages playing a significant role in PPCP removal. The system is effective in removing four kinds of pollutants: AMP, IBU, CLR, and CAF, and the removal efficiency of CAF is up to 99.2%. Seasonal variations significantly affect the removal of PPCPs and bacterial growth, leading to changes in bacterial species. At the genus level, 41 bacterial types presented different effects in response to temperature changes, with Trichoderma and c_OM190_unclassified being the most affected. This study provides essential theoretical support for reducing pollutant levels and improving water recycling and economic efficiency.