Wastewater treatment plants (WWTPs) are key reservoirs of antibiotic resistance genes (ARGs), with municipal sludge containing high bacterial densities and diverse ARGs that may spread through land application. Hydrothermal treatment (HT) is a process that inactivates pathogens and stabilizes biomass, but its performance at moderate temperatures is less understood. We evaluated HT (100°C–250°C; 2–24 h) for degrading bacterial DNA and ARGs in dewatered municipal sludge. DNA was quantified by fluorometry, bacterial presence confirmed by 16S rRNA gene PCR, and ARGs profiled by qPCR targeting 84 clinically and environmentally relevant genes. HT up to 250°C produced modest carbon densification, high solids recovery and low gas yields. DNA persisted at 100°C but was undetectable at ≥ 150°C for 2 h, with complete ARG removal. These findings demonstrate that moderate HT effectively eliminates DNA and ARGs while preserving nutrient value, supporting its potential as a sustainable, scalable sludge sanitation strategy to mitigate ARG risks.
Ph.D. et al. (Tue,) studied this question.