Biogas production from supernatant of hydrothermally treated municipal sludge by upflow anaerobic sludge blanket reactor

• Published in: Bioresource technology 2011-11, Vol.102 (21), p.9904-9911
• Main Authors: Qiao, Wei, Peng, Chong, Wang, Wei, Zhang, ZhongZhi
• Format: Article
• Language: English
• Subjects: Ammonia - analysis; Anaerobiosis; Applied sciences; Biodegradation, Environmental; Biofuel production; Biofuels - analysis; Biogas; Biological and medical sciences; Biological Oxygen Demand Analysis; Bioreactors; Bioreactors - microbiology; Biotechnology; China; Cities; Crack opening displacement; Energy; Environmental Restoration and Remediation - instrumentation; Environmental Restoration and Remediation - methods; Exact sciences and technology; Fluctuation; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Hydrothermal treatment; Industrial applications and implications. Economical aspects; Influents; Mathematical analysis; Methods. Procedures. Technologies; Municipal sludge; Oxygen - metabolism; Pollution; Reactors; Running; Sewage - analysis; Sewage - microbiology; Sludge; Temperature; Thermodynamics; UASB; UASB reactors; Various methods and equipments; Waste Disposal, Fluid - instrumentation; Wastes; Wastewaters; Water - chemistry; Water treatment and pollution
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2011.08.037

► Biogas recovery from a hydrothermally treated sludge supernatant was tested by a 550days running UASB reactor. ► The UASB reactor could achieve a high methane production rate and show a stable performance. ► Granular sludge could grow with the supernatant substrate. ► The methane-produced energy was higher than the energy consumed. The supernatant of hydrothermally treated sludge was treated by an upflow anaerobic sludge blanket (UASB) reactor for a 550-days running test. The hydrothermal parameter was 170°C for 60min. An mesophilic 8.6L UASB reactor was seeded with floc sludge. The final organic loading rate (OLR) could reach 18kg COD/m3d. At the initial stage running for 189days, the feed supernatant was diluted, and the OLR reached 11kg COD/m3d. After 218days, the reactor achieved a high OLR, and the supernatant was pumped into the reactor without dilution. The influent COD fluctuated from 20,000 to 30,000mg/L and the COD removal rate remained at approximately 70%. After 150days, granular sludge was observed. The energy balance calculation show that heating 1.0kg sludge needs 0.34MJ of energy, whereas biogas energy from the supernatant of the heated sludge is 0.43MJ.