title: Sulfate addition as an effective method to improve methane fermentation performance and propionate degradation in thermophilic anaerobic co-digestion of coffee grounds, milk and waste activated sludge with AnMBR.
abstract: This study was conducted to investigate the effects of sulfate on propionate degradation and higher organic loading rate (OLR) achievement in a thermophilic AnMBR for 373days using coffee grounds, milk and waste activated sludge (WAS) as the co-substrate. Without the addition of sulfate, the anaerobic system failed at an OLR of 14.6g-COD/L/d, with propionate accumulating to above 2.23g-COD/L, and recovery by an alkalinity supplement was not successful. After sulfate was added into substrates at a COD/SO4(2-) ratio of 200:1 to 350:1, biogas production increased proportionally with OLR increasing from 4.06 to 15.2g-COD/L/d. Propionic acid was maintained at less than 100mg-COD/L due to the effective conversion of propionic acid to methane after the sulfate supplement was added. The long-term stable performance of the AnMBR indicated that adding sulfate was beneficial for the degradation of propionate and achieving a higher OLR under the thermophilic condition.
authors: Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China; Dept. of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, Japan.
authors: Qian
authors: Q
authors: Li
authors: Dept. of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, Japan; Graduate School of Environmental Studies, Tohoku University, Sendai 980-8579, Japan. Electronic address: yyli@epl1.civil.tohoku.ac.jp.
authors: Yu-You
authors: YY
authors: Li
authors: College of Engineering, China Agriculture University, Beijing 10081, China; Key Laboratory for Soild Waste Management and Environment Safety, Ministry of Education of China, Tsinghua University, Beijing 100084, China.
authors: Wei
authors: W
authors: Qiao
authors: Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China.
authors: Xiaochang
authors: X
authors: Wang
authors: Dept. of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Aoba-ku, Sendai 980-8579, Japan.
authors: Kazuyuki
authors: K
authors: Takayanagi
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D056804:Biofuels; D019149:Bioreactors; D003069:Coffee; D005285:Fermentation; D008697:Methane / Q000737:chemistry*; D008892:Milk; D011422:Propionates / Q000737:chemistry*; D012037:Refuse Disposal / Q000379:methods; D012722:Sewage; D013431:Sulfates / Q000737:chemistry*; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D056804:Biofuels; D003069:Coffee; D011422:Propionates; D012722:Sewage; D013431:Sulfates; C029658:propionic acid; D008697:Methane
keywords: Anaerobic co-digestion; Coffee grounds; Propionate degradation; Sulfate addition; Thermophilic