Advanced digestion process development for methane production from biomass: waste blends
A series of exploratory anaerobic digestion experiments was performed with a mixed biomass-waste feed to search for digestion configurations that provide improved performance over that of conventional high-rate digestion. The techniques studied were pretreatment of the feed with caustic soda, product gas recycling to the digester, recycling of aerobically treated digester effluent to the digester, two-phase digestion with complete mix acid- and methane-phase reactors, and packed-bed, methane-phase digestion of the effluent from an acid-phase reactor. Ambient-temperature pretreatment of the feed blend with dilute caustic and recycling of the product gas each afforded higher methane yields and volatile solids reduction efficiencies than high-rate digestion alone. It was found that spent caustic could be recycled for fresh feed pretreatment and that neutralization was not necessary before feeding to the digester. Two-phase digestion in the complete-mix reactors gave methane yields and reduction efficiencies about the same as those of high-rate digestion but at much higher loadings and reduced detention times thereby offering significant reductions in equipment size for the same throughputs. The use of a packed-bed anaerobic filter as a methane-phase reactor also showed considerable promise for operation at reduction detection times when the filter effluent was recycled to the filter inlet. Analysis of the data from the experiments conducted to study each advanced digestion technique indicates that an integrated series of unit processes consisting of dilute caustic pretreatment, thermophilic acid-phase digestion, mesophilic complete-mix and packed-bed methane-phase digestion, and limited-aeration aerobic treatment of the methane-phase effluents coupled with recycling should exhibit digestion efficiencies and methane yields near the upper practical limits.
- Research Organization:
- Inst. of Gas Tech., Chicago, IL
- OSTI ID:
- 6488818
- Report Number(s):
- CONF-790415-P8
- Journal Information:
- ACS Symp. Ser.; (United States), Vol. 144; Conference: 177. national meeting of the American Chemical Society, Honolulu, HI, USA, 1 Apr 1979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANAEROBIC DIGESTION
OPTIMIZATION
GRASS
ALKALINE HYDROLYSIS
METHANE
BIOSYNTHESIS
MUNICIPAL WASTES
SEWAGE SLUDGE
WATER HYACINTHS
EFFICIENCY
GAS YIELDS
LIQUID WASTES
RECYCLING
SOLID WASTES
ALKANES
AQUATIC ORGANISMS
BIOCONVERSION
CHEMICAL REACTIONS
DECOMPOSITION
DIGESTION
HYDROCARBONS
HYDROLYSIS
LYSIS
MANAGEMENT
ORGANIC COMPOUNDS
PLANTS
PROCESSING
SEWAGE
SOLVOLYSIS
SYNTHESIS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
YIELDS
090122* - Hydrocarbon Fuels- Preparation from Wastes or Biomass- (1976-1989)
140504 - Solar Energy Conversion- Biomass Production & Conversion- (-1989)