Effects of lipid concentration on anaerobic co-digestion of municipal biomass wastes.
The influence of the lipid concentration on the anaerobic co-digestion of municipal biomass waste and waste-activated sludge was assessed by biochemical methane potential (BMP) tests and by bench-scale tests in a mesophilic semi-continuous stirred tank reactor. The effect of increasing the volatile solid (VS) concentration of lipid from 0% to 75% was investigated. BMP tests showed that lipids in municipal biomass waste could enhance the methane production. The results of bench-scale tests showed that a lipids concentration of 65% of total VS was the inhibition concentration. Methane yields increased with increasing lipid concentration when lipid concentrations were below 60%, but when lipid concentration was set as 65% or higher, methane yields decreased sharply. When lipid concentrations were below 60%, the pH values were in the optimum range for the growth of methanogenic bacteria and the ratios of volatile fatty acid (VFA)/alkalinity were in the range of 0.2-0.6. When lipid concentrations exceeded 65%, the pH values were below 5.2, the reactor was acidized and the values of VFA/alkalinity rose to 2.0. The amount of Brevibacterium decreased with increasing lipid content. Long chain fatty acids stacked on the methanogenic bacteria and blocked the mass transfer process, thereby inhibiting anaerobic digestion.
School of Chemistry and Environment, Beihang University, Beijing 100191, China. Electronic address: sunif@buaa.edu.cn.
Yifei
Y
Sun
School of Chemistry and Environment, Beihang University, Beijing 100191, China.
Dian
D
Wang
School of Chemistry and Environment, Beihang University, Beijing 100191, China.
Jiao
J
Yan
College of Chemical Science and Engineering, China University of Petroleum, Beijing 102249, China.
Wei
W
Qiao
School of Environment, Tsinghua University, Beijing 100084, China.
Wei
W
Wang
School of Chemistry and Environment, Beihang University, Beijing 100191, China.
Tianle
T
Zhu
D000693:Anaerobiosis; D018407:Bacterial Physiological Phenomena; D044822:Biodiversity; D006863:Hydrogen-Ion Concentration; D008055:Lipids / Q000032:analysis* / Q000737:chemistry; D008697:Methane / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid
D008055:Lipids; D012722:Sewage; D008697:Methane
Anaerobic digestion; Inhibition; LCFA; Lipid; Municipal biomass waste