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Wastewater treatment plants have been identified as an important gathering spot for nanoplastics, possibly having unintended impacts on important biological nutrient removal processes. The underlying effects of long-term exposure of activated sludge to nanoplastics on nutrient removal and the mechanisms involved remain unclear. This study investigated the effect of polystyrene nanoplastics (Nano-PS) on the treatment performance and microbial community structure, and network in activated sludge. The results indicate that 1000 μg/L Nano-PS had chronic negative effects on the treatment performance in a continuous test over 140 days. Nano-PS had no significant impact in the earlier stages (0-50 days). However, as exposure time increased, the removal efficiencies of chemical oxygen demand, total phosphorous, and total nitrogen (TN) decreased by 2.7, 33.2, and 23.5%, respectively, in the later stages (87-132 days). These adverse impacts further manifested as a change in the topological characteristics, forming a smaller scale, lower complexity, and weaker transfer efficiency of the microbial network. Moreover, the scale and complexity of subnetwork-nitrogen removal bacteria and subnetwork-nitrifier were inhibited, leading to an increase in the effluent TN and NH |
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