This study aimed to evaluate the effect of thermal pretreatment on anaerobic digestion (AD) of dewatered sludge. Thermal pretreatment was conducted at varying temperatures (40–220 °C) and durations (1–3 h), prior to batch biomethane production. The highest biomethane yield of 195 mL CH4/g VSfeed was achieved at 140 °C for 3 h, which was 81% higher than that of the control. However, the net cash flow of 76,942 USD/yr was achieved at 60 °C for 3 h. The solubilization of chemical oxygen demand and cell lysis were accompanied by a relative abundance of Firmicutes in the bacterial population during batch digestion, implying that thermal pretreatment promoted the growth of hydrolytic bacteria. In the methanogenic archaeal population, the proportion of hydrogenotrophs and electrotrophs increased, indicating that pretreatment enhanced the interspecies transfer of H2 and electrons. Economic analysis revealed that pretreatment at 40 °C for 1 h, 60 °C for 1–3 h and 100 °C for 3 h could be beneficial to AD of dewatered sludge. However, a sensitivity analysis confirmed that 60 °C for 3 h is the most economical pretreatment condition. AD accompanied by mild thermal pretreatment is a viable treatment method for dewatered sludge discharged from small wastewater treatment facilities.
Bibliographical noteFunding Information:
This work was supported by Korea Environment Industry & Technology Institute (KEITI) through Project for developing innovative drinking water and wastewater technologies, funded by Ministry of Environment (MOE), Republic of Korea ( ARQ202001174001 ). This work was also supported by the Technology development Program ( S3138121 ) funded by the Ministry of SMEs and Startups (MSS, Republic of Korea).
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All Science Journal Classification (ASJC) codes
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- Modelling and Simulation
- Renewable Energy, Sustainability and the Environment
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