Genus-Level Microbial Fingerprints Predict Estrogen and Nonylphenol Biodegradation in Activated-Sludge Reactors

Endocrine-disrupting chemicals (EDCs) accumulate in soils and surface waters, where their hormone-mimicking activity threatens aquatic ecosystems, food security and human health. Although many bacteria can degrade estrogens and nonylphenols in pure culture, field-scale performance data remain scarce. Here, a pilot activated-sludge plant treating municipal sewage was operated at solids-retention times (SRTs) of 3, 10 and 27 days, thereby also lengthening the hydraulic retention time (HRT), to reshape the microbial community and track EDCs fate. Increasing both the SRT and HRT enriched Rhizomicrobium, Planctomyces, Mesorhizobium and Hyphomicrobium, whose abundances correlated strongly (r > 0.70) with removal of estrone, 17β-estradiol and estriol. In contrast, variability in Mycobacterium, Variovorax and Nannocystis explained differences in 17α-ethinylestradiol elimination. Parent nonylphenol removal tracked Roseiflexus, Turicibacter and Polyangium, while Paracoccus, Novosphingobium and Sphingomonas signalled degradation of nonylphenol-triethoxy-carboxylate. Increasing the SRT raised median removals for most estrogens and long-chain nonylphenol ethoxylates from < 55% to > 85%, whereas recalcitrant 17α-ethinylestradiol and short-chain nonylphenol congeners improved more modestly. Genus-level fingerprints therefore predicted treatment efficacy: a nucleus of versatile degraders (Hyphomicrobium, Rhizomicrobium, Kaistia) co-varied with simultaneous attenuation of steroidal estrogens and nonylphenol derivatives. These insights provide quantitative design criteria for data-driven monitoring and real-time optimisation of full-scale plants facing increasingly stringent EDC discharge limits.