Peer-Reviewed Journal Details
Mandatory Fields
Nizami, AS;Murphy, JD
2011
September
Environmental Science & Technology
Optimizing the Operation of a Two-Phase Anaerobic Digestion System Digesting Grass Silage
Validated
WOS: 47 ()
Optional Fields
WASTE-WATER TREATMENT UASB REACTOR METHANE PRODUCTION ENERGY CROPS SLUDGE GRANULATION HYDROLYSIS BIOREACTOR BIOMETHANE GRANULES
45
7561
7569
This paper examines the optimization of an existing two-phase anaerobic digestion process using grass silage as a feedstock. The system comprises 6 leach beds connected to an upflow anaerobic sludge blanket (UASB). The existing system produced 305 L CH(4) kg(-1) VS added at an overall retention time of 42 days (6 leach beds emptied and fed sequentially every 7 days in series). The desired improvements were a reduction in retention time with increased methane production. It was noted in the existing system that biogas production and COD levels fell off in the last 2 days of each 7-day cycle. Thus the first change involved reduction in retention time to 30 days (6 leach beds fed sequentially every 5 days in series). This lead to a slight improvement in methane production (310 L CH(4) kg(-1) VS added). The second change was effected by separation of flows to the first stage (leach beds) and the second stage (UASB) through addition of an extra pump to optimize leaching. This led to an increase in CH(4) production (341 L CH(4) kg(-1) VS). The overall improvement from the existing system was an increase of 11.8% in methane production and a reduction in size or retention time of 40% (42 days decreased to 30 days retention time).
WASHINGTON
0013-936X
10.1021/es201357r
Grant Details