title: Potential and optimization of two-phase anaerobic digestion of oil refinery waste activated sludge and microbial community study.
abstract: Oil refinery waste activated sludge produced from oil wastewater biological treatment is a major industrial sludge. Two-phase anaerobic digestion of oil refinery waste activated sludge was studied for the first time. Thermal pretreatment under 170 °C is effective on sludge solubilization. At the optimum hydrolytic-acidogenic condition which was pH of 6.5, temperature of 55 °C and HRT of 2 days, 2754 mg/L volatile fatty acids (VFAs) were produced and acetic acid and butyric acid were the key components. Comparative studies of single-phase and two-phase anaerobic digestion in terms of organic removal, biogas production and methane concentration were conducted. The cumulative methane production and soluble COD (SCOD) removal efficiency in the two-phase system were 228 mL/g COD added and 77.8%, respectively, which were 1.6 and 2.1 times higher than those in single-phase anaerobic digestion. Such improved performance is attributed to intensification of dominant microbial population in separated reactors. Caloramator, Ureibacillus, Dechloromonas, Petrobacter, and T78 played important roles in hydrolytic-acidification and oil-organics degradation. Syntrophic bacteria in the family Porphyromonadaceae and the genus Anaerobranca provide acetate for methanogen. The results demonstrated the potential and operating condition of two-phase anaerobic digestion in treatment of oil refinery waste activated sludge.
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Oil &Gas Pollution Control, China University of Petroleum, Beijing 102249, PR China.
authors.forename: Qinghong
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Oil &Gas Pollution Control, China University of Petroleum, Beijing 102249, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liang
authors.affiliation: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, PR China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhao
authors.affiliation: Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
authors.forename: Qing X
authors.initials: QX
authors.lastname: Li
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Oil &Gas Pollution Control, China University of Petroleum, Beijing 102249, PR China.
authors.forename: Shaohui
authors.initials: S
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Oil &Gas Pollution Control, China University of Petroleum, Beijing 102249, PR China.
authors.forename: Chunmao
authors.initials: C
authors.lastname: Chen
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism*; D006868:Hydrolysis; D008697:Methane / Q000378:metabolism*; D010578:Petroleum / Q000382:microbiology*; D012722:Sewage / Q000382:microbiology*; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification
chemical_list: D010578:Petroleum; D012722:Sewage; D014874:Water Pollutants, Chemical; D008697:Methane