A process combining hydrothermal pretreatment, anaerobic digestion and pyrolysis for sewage sludge dewatering and co-production of biogas and biochar: Pilot-scale verification. (April 2018)

• Record Type: Journal Article
• Authors: Li, Chunxing; Wang, Xingdong; Zhang, Guangyi; Li, Jie; Li, Zhiwei; Yu, Guangwei; Wang, Yin
• Is Part Of: Bioresource technology. Volume 254(2018)
• Page Start: 187
• Page End: 193
• Publication Date: 2018-04
• Subjects: Sewage sludge -- Hydrothermal pretreatment -- Anaerobic digestion -- Pyrolysis -- Heavy metal -- Energy balance; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2018.01.045
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: A process (HTPT, AD and pyrolysis) was proposed for full utilization of sewage sludge. The process was successfully operated at pilot scale. The whole process was slightly deficient in energy. Heavy metals were well immobilized during biochar production. The biochar yield was 9.6 t/100 t sewage sludge. Abstract: To fully dispose of/utilize sewage sludge, a process combing hydrothermal pretreatment (HTPT), anaerobic digestion (AD) and pyrolysis was developed and tested at the pilot scale. First, the improvement in sludge dewaterability by HTPT at 180 °C for 30 min was verified, and the water content decreased from 85 to 33 wt% after filter pressing. Then, the resulting filtrate underwent continuous mesophilic (37 ± 2 °C) AD in an up-flow anaerobic sludge bed (UASB) reactor for producing biogas to compensate for the energy required for HTPT. Meanwhile, the filter cake was pyrolyzed in a rotary furnace (600 ± 50 °C) to generate biochar, and heavy metals were well immobilized in the biochar. Finally, the material/energy balance made according to the pilot data showed that the proposed process was effective for full resource reuse of sewage sludge.