Parameter-optimized hydrothermal carbonization of swine manure for carbon recovery integrated antibiotic degradation and derived wastewater fertilization

This work investigated the hydrothermal degradation of typical antibiotics present in swine manure (SW) under varying reaction parameters and evaluated the potential of hydrothermal carbonization (HTC) products as high-value carbon materials and liquid fertilizers. The results indicate that doxycycline, sulfadiazine and enrofloxacin were completely degraded under the HTC condition of 260 °C and 40 min, while the optimal HTC conditions for SW were identified as 300 °C, 40 min, and a solid-liquid ratio of 0.1 g/mL. Analysis of the HTC products revealed that hydro-char exhibited favorable surface morphology, a high degree of carbonization, the ability to stabilize heavy metals, a high higher heating value (HHV), and excellent thermal stability. Furthermore, the hydrothermal wastewater complies with discharge standards in terms of heavy metal content, antibiotic concentration, and drug-resistant bacteria content. It also contains significant amount of nitrogen and potassium, along with moderate phosphorus content, highlighting its potential as a liquid fertilizer. This study provides novel insights into the harmless and resourceful utilization of SW and can also serve as a valuable reference for the treatment of other organic waste.