Anaerobic waste-activated sludge digestion - A bioconversion mechanism and kinetic model
- Hokkaido Univ., Sapporo (Japan)
The anaerobic bioconversion of raw and mechanically lysed waste-activated sludge was kinetically investigated. The hydrolysis of the biopolymers, such as protein, which leaked out from the biological sludge with ultrasonic lysis, was a first-order reaction in anaerobic digestion and the rate constant was much higher than the decay rate constant of the raw waste activated sludge. An anaerobic digestion model that is capable of evaluating the effect of the mechanical sludge lysis on digestive performance was developed. The present model includes four major biological processes - the release of intracellular matter with sludge lysis; hydrolysis of biopolymers to volatile acids; the degradation of various volatile acids to acetate; and the conversion of acetate and hydrogen to methane. Each process was assumed to follow first-order kinetics. The model approximately simulated the overall process performance of the anaerobic digestion of waste-activated sludge. The model suggested that when the lysed waste-activated sludge was fed, the overall digestive performance remarkably increased in the two-phase system consisting of an acid forming process and a methanogenic process, which ensured the symbiotic growth of acetogenic and methanogenic bacteria.
- OSTI ID:
- 6806750
- Journal Information:
- Biotechnology and Bioengineering; (United States), Vol. 41:11; ISSN 0006-3592
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
METHANE
BIOSYNTHESIS
METHANOGENIC BACTERIA
GROWTH
ANAEROBIC DIGESTION
MATHEMATICAL MODELS
SEWAGE SLUDGE
ALKANES
BACTERIA
BIOCONVERSION
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
DIGESTION
HYDROCARBONS
MANAGEMENT
MATERIALS
MICROORGANISMS
ORGANIC COMPOUNDS
PROCESSING
SEWAGE
SLUDGES
SYNTHESIS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
090900* - Biomass Fuels- Processing- (1990-)