Fermentation of particulate organic matter to methane in a thermophilic anaerobic attached film expanded bed reactor

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6819840

Clarkson, W W

The anaerobic attached film expanded bed (AAFEB) has been applied to dilute sewage at low temperatures and to soluble organics at thermophilic temperatures. In this study, microcrystalline cellulose was used to determine the sites and rates of particle conversion to methane in bench-scale AAFEB reactors at 55/sup 0/C. The reactors had expanded bed volumes of 500 ml composed of inert diatomaceous earth grains approximately 0.4 mm in diameter supporting thin films. Methanogenic biofilms could be established on soluble feed within 30 days. Over a 27-month experimental period, cellulose was fed to the expanded beds at volumetric loads from 2 to 69 g COD/lxd. Total COD conversion efficiencies were 90 to 20% and cellulose solubilization efficiencies were 92 to 53% in the methane forming reactors. Hydrolysis was mediated by suspended bacteria colonizing the cellulose particles. High slug cellulose loads to the AAFEB indicated a maximum potential hydrolysis rate in excess of 75 g COD/lxd, which exceeds the maximum reported methanogenesis rate. Suspended-growth reactors were used to determine kinetic parameters of the hydrolytic bacteria at 55/sup 0/C. Specific cellulose conversion rate was 4.8 g COD/g cellsxd, equivalent to values calculated from the AAFEB data. Yield of hydrolyzers = 0.22 g VS/g CODxd, and decay coefficients = 0.05 d/sup -1/. A small amount of methane was produced at SRT as low as 1.5 days at pH 6. Biofilm reactors were found to be stable and capable of efficient conversion of high loadings of organic suspended solids. Biofilm and suspended bacteria play unique roles in the process.

• Research Organization: Cornell Univ., Ithaca, NY (USA)
• OSTI ID: 6819840
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
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ALKANES
ANAEROBIC DIGESTION
BENCH-SCALE EXPERIMENTS
BIOCHEMICAL REACTION KINETICS
BIOCONVERSION
BIOREACTORS
BIOSYNTHESIS
CARBOHYDRATES
CELLULOSE
CHEMICAL OXYGEN DEMAND
DESIGN
DIGESTION
HYDROCARBONS
KINETICS
LOADING RATE
MANAGEMENT
METHANE
ORGANIC COMPOUNDS
PERFORMANCE TESTING
POLYSACCHARIDES
PROCESSING
REACTION KINETICS
SACCHARIDES
SEWAGE
SYNTHESIS
TESTING
THERMOPHILIC CONDITIONS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES