Synergistic bioremediation and resource recovery via photosynthetic bacteria treatment of swine manure hydrothermal carbonization wastewater

This study investigates an innovative approach for high-value utilization of high-concentration swine manure (SM) through hydrothermal carbonization (HTC) combined with photosynthetic bacteria (PSB) treatment. The HTC-derived wastewater quality indices including pH, nutrient concentrations, antibiotic residues, and antibiotic-resistant bacteria were characterized. The optimal HTC conditions are identified as 300 °C reaction temperature, 40 min reaction time, and 0.1 g/mL SM loading, which results in a marked reduction in chemical oxygen demand (COD) to 31,200 mg/L in the HTC-derived wastewater. Subsequently, the HTC-derived wastewater was employed for PSB cultivation. The ideal PSB treatment configuration involves mixed bacterial consortia, a 15-fold dilution ratio, and microaerobic operation conditions. The optimized conditions facilitate effective microbial growth, producing a commercial-grade PSB bioagent compliant with national quality specifications. The residual COD content is comparable to that in commercial PSB bioagents. This work provides valuable insights for the sustainable management of SM, achieving full elimination of pollutants and resource recovery. • The feasibility of integrating HTC with PSB treatment for swine manure is verified. • The characteristics of high concentration HTC-Derived wastewater are investigated. • The optimum conditions for PSB to utilize HTC-derived wastewater are studied.