Hydrothermal carbonization of sewage sludge: Catalytic effect of Cl− on hydrochars physicochemical properties

Potential Application Performance of Hydrochar from Kitchen Waste: Effects of Salt, Oil, Moisture, and pH

The surge in kitchen waste production is causing food-borne disease epidemics and is a public health threat worldwide. Additionally, the effectiveness of conventional treatment approaches may be hampered by KW's high moisture, salt, and oil content. Hydrothermal carbonization (HTC) is a promising new technology to convert waste biomass into environmentally beneficial derivatives. This study used simulated KW to determine the efficacy of hydrothermal derivatives (hydrochar) with different salt and oil content, pH value, and solid-liquid ratio for the removal of cadmium (Cd) from water and identify their high heating value (HHV). The findings revealed that the kitchen waste hydrochar (KWHC) yield decreased with increasing oil content. When the water content in the hydrothermal system increased by 90%, the yield of KWHC decreased by 65.85%. The adsorption capacity of KWHC remained stable at different salinities. The KWHC produced in the acidic environment increases the removal efficiency of KWHC for Cd. The raw material was effectively transformed into a maximum HHV (30.01 MJ/kg). HTC is an effective and secure method for the resource utilization of KW based on the adsorption capacity and combustion characteristic indices of KWHC.

Evaluations of biochar amendment on anaerobic co-digestion of pig manure and sewage sludge: waste-to-methane conversion, microbial community, and antibiotic resistance genes

Effects of biochar on co-digestion of pig manure and dewatered sewage sludge under different total solids (TS) were investigated. Biochar could accelerate the start-up of methanogenesis and shorten the adaptation phase. At TS5%, the methane daily production in biochar group was 60.6% higher than the control; nevertheless, when TS increased, the gap between two groups gradually narrowed. Additionally, the change on antibiotics resistance genes (ARGs) was also affected by TS and the biochar addition. Moreover, biochar was beneficial to reduce ARGs in liquid phase. At TS14%, the total ARGs abundance in the liquid phase of biochar group was 41.4% lower than the control, among which the reduction rates of etB(P), sul1, rpoB2, macA, mupA and mupB were more prominent. These findings could provide useful guidance for developing ARGs elimination strategy before their release into the environment.