Insights into anaerobic transformation of key dissolved organic matters produced by thermal hydrolysis sludge pretreatment

• Published in: Bioresource technology Vol. 266; pp. 60 - 67
• Main Authors: Lu, Dan, Sun, Faqian, Zhou, Yan
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2018
• Subjects: Anaerobic digestion; aromatic compounds; biodegradability; Dissolved organic matters; flavonoids; methane production; molecular weight; polysaccharides; pyridines; Refractory compounds; sludge; solubilization; temperature; thermal hydrolysis; Thermal hydrolysis pretreatment; Thermal hydrolysis pretreatment; Refractory compounds; Anaerobic digestion; Dissolved organic matters
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2018.06.059

[Display omitted] •High temperature sludge treatment mainly improved the release of LMW matters.•LMW DOMs after THP were closely correlated with biogas generation.•The residual DOMs after AD were mainly HS, LMW PN and LMW neutrals.•Steroids and aromatics were dominant in residual LMW refractory compounds. The detailed dissolved organic matters (DOMs) profile by thermal hydrolysis pretreatment and their transformation during anaerobic digestion (AD) were investigated. Among the temperature tested, 172 °C treatment showed the best sludge solubilization and the maximum methane production. The study revealed that high temperature sludge pretreatment mainly improved the release of low molecular weight (LMW) proteins, LMW neutrals and LMW polysaccharides. Notably, the effluent from thermal treated sludge digesters contained more DOMs residues. The predominant residual DOMs were humic substances, LMW proteins and LMW neutrals. At the molecular level, over 50% of the residual LMW components were slowly biodegradable or nonbiodegradable steroid-like compounds and aromatics. Further profiling of the higher MW compounds detected the recalcitrant or inhibitory compounds, e.g. benzenoids, flavonoids, pyridines and their derivatives. It is recommended that polishing step should be considered to further reduce the refractory residues in AD liquor.