14 / 2023-04-26 14:43:59

Co-production of humic acids and biogas from chicken manure and corn straw via stepwise hydrothermal treatment and anaerobic digestion

hydrothermal treatment,humic acids,anaerobic digestion,organic waste

The resource utilization of organic waste rases increasing attention, among which livestock manure and agriculture waste represents as two of the most abundant organic waste. In this study, co-production of humic acids (HA) and biogas from chicken manure (CM) and corn straw (CS) via stepwise hydrothermal treatment and anaerobic digestion were investigated. Results showed the hydrothermal liquid produced from hydrothermal treatment of CM and CS was rich in HAs and chemical oxygen demand (COD), which was highly associated with the CM and CS ratio. The highest COD content was obtained at the CM to CS ratio of 1:0, which was 58390 mg/L. The highest HAs content was obtained at the CM to CS ratio of 0:1, which was 28.64% (% of the substrate added). The high HAs and COD concentration simultaneously achieved at the CM to CS ratio of 1:1, which were 27.44% (% of the substrate added) and 52820 mg/L, respectively. When using the hydrothermal products (hydrothermal solid and hydrothermal liquid) for anaerobic digestion (AD), the hydrothermal liquid obtained faster start-up and shorter fermentation period. Maximum methane yield of 527.1 mL was obtained from the hydrothermal liquid produced at the CM to CS ratio of 2:1. AD of the mixture of hydrothermal solid and hydrothermal liquid obtained higher methane yield and longer lag-phase time. There was no obvious methane production until the 15^th day of AD. Maximum methane yield of 1153.5 mL was obtain from the e mixture of hydrothermal solid and hydrothermal liquid produced at the CM to CS ratio of 1:2. In addition to the HAs and methane production, hydrothermal treatment also achieved high tetracycline hydrochloride degradation ratio (about 95%). To sum up, this study developed a strategy of co-production of HAs and biogas from chicken manure and corn straw via stepwise hydrothermal treatment and anaerobic digestion, which provide promising choice for organic waste treatment.