Effect, Fate and\nRemediation of Pharmaceuticals and\nPersonal Care Products (PPCPs) during Anaerobic Sludge Treatment:\nA Review

Biomass energy recovery from sewage sludge through anaerobic\ntreatment\nis vital for environmental sustainability and a circular economy.\nHowever, large amounts of pharmaceutical and personal care products\n(PPCPs) remain in sludge, and their interactions with microbes and\nenzymes would affect resource recovery. This article reviews the effects\nand mechanisms of PPCPs on anaerobic sludge treatment. Most PPCPs\nposed adverse impacts on methane production, while certain low-toxicity\nPPCPs could stimulate volatile fatty acids and biohydrogen accumulation.\nChanges in the microbial community structure and functional enzyme\nbioactivities were also summarized with PPCPs exposure. Notably, PPCPs\nsuch as carbamazepine could bind with the active sites of the enzyme\nand induce microbial stress responses. The fate of various PPCPs during\nanaerobic sludge treatment indicated that PPCPs featuring electron-donating\ngroups (e.g., ·–NH<sub>2</sub> and ·–OH),\nhydrophilicity, and low molecular weight were more susceptible to\nmicrobial utilization. Key biodegrading enzymes (e.g., cytochrome\nP450 and amidase) were crucial for PPCP degradation, although several\nPPCPs remain refractory to biotransformation. Therefore, remediation\ntechnologies including physical pretreatment, chemicals, bioaugmentation,\nand their combinations for enhancing PPCPs degradation were outlined.\nAmong these strategies, advanced oxidation processes and combined\nstrategies effectively removed complex and refractory PPCPs mainly\nby generating free radicals, providing recommendations for improving\nsludge detoxification.