Effect of Fe0addition on volatile fatty acids evolution on anaerobic digestion at high organic loading rates.
Excessive acidification frequently occurs in the anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) at high organic loading rates (OLR), due to the accumulation of non-acetic volatile fatty acids (VFA). In this study, the performance of Fe0in enhancing various VFA production and metabolism was investigated. The butyric acid concentration in a high OLR reactor with Fe0addition decreased from 7200 to 0mg/L after a short lag phase, and the total VFA (TVFA) concentration also decreased substantially. The corresponding dominant acidogenesis type also changed from butyric type to propionic type fermentation. Furthermore, the CH4yield of the reactor with added Fe0was approximately 595ml CH4/g VSadded, which was an increase of 41.7% compared with the biochemical methane potential (BMP) test results in controls without added ZVI. A microbial diversity analysis, using high throughput sequencing, showed that Methanofollis and Methanosarcina were dominant in terms of the archaeal structures of the Fe0reactor at the butyric converting stage; however, Methanosaeta was predominant in the reactor during the control BMP test. These results suggested that Fe0can convert non-acetic VFA to acetic VFA and improve the CH4yield by enhancing the activity of methanogens.
Key Laboratory for Solid Waste Management and Environment Safety, Ministry of Education of China, School of Environment, Tsinghua University, Beijing 10084, China.
Xin
X
Kong
Key Laboratory for Solid Waste Management and Environment Safety, Ministry of Education of China, School of Environment, Tsinghua University, Beijing 10084, China.
Shuyao
S
Yu
Key Laboratory for Solid Waste Management and Environment Safety, Ministry of Education of China, School of Environment, Tsinghua University, Beijing 10084, China.
Shuang
S
Xu
Key Laboratory for Solid Waste Management and Environment Safety, Ministry of Education of China, School of Environment, Tsinghua University, Beijing 10084, China.
Wen
W
Fang
Key Laboratory for Solid Waste Management and Environment Safety, Ministry of Education of China, School of Environment, Tsinghua University, Beijing 10084, China. Electronic address: jgliu@tsinghua.edu.cn.
Jianguo
J
Liu
Shenzhen Environmental Microbial Application and Risk Control Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
Huan
H
Li
D000693:Anaerobiosis; D019149:Bioreactors; D020148:Butyric Acid; D005232:Fatty Acids, Volatile / Q000378:metabolism*; D008697:Methane / Q000032:analysis; D062611:Solid Waste
D005232:Fatty Acids, Volatile; D062611:Solid Waste; D020148:Butyric Acid; D008697:Methane
Anaerobic digestion; Butyric type fermentation; Microbial diversity; OFMSW; Zero-valent iron