Modeling fatty acid relationships in animal waste anaerobic digesters

Journal Article · Thu Jan 01 04:00:00 EST 1987 · Trans. ASAE; (United States)

DOI:https://doi.org/10.13031/2013.31978· OSTI ID:5694587

Hill, D T; Bolte, J P

Volatile fatty acid (VFA) relationships are important in the anaerobic digestion of animal wastes as they (acetic, propionic and butyric) are direct precursors of methane, either through direct conversion of acetate or through the intermediate formation of hydrogen and carbon dioxide. Thus, they are essential compounds in the biological conversion of heterogenous wastes to useable products. VFA's are also known inhibitors in the biological conversion process if their concentrations are sufficiently high. Thus, VFA's are simultaneously essential for the process and can be toxic agents should they be present in excess quantities. This relationship makes quantifying VFA's in the modeling studies essential to accurately predicting digester failure or success. A highly correlated relationship between the level of acetic acid and/or the propionic to acetic acid ratio in digesters that were successful and in digesters that failed has been shown. These data have been used to calibrate an original comprehensive methanogenesis model and along with the addition of dual-use substrate kinetics for the simultaneous catalysis of propionate and butyrate, have produced a much improved prediction of the VFA relationships observed in operating anaerobic digesters. This manuscript describes the addition of the dual-use substrate kinetics and the modification of the kinetic parameters of the original methanogenic model and compared the simulated output of the original and modified models to demonstrate the improved predictive ability. (Refs. 12).

• Research Organization: Auburn Univ., AL. Agricultural Engineering Dept., Alabama Agricultural Experiment Station
• OSTI ID: 5694587
• Journal Information: Trans. ASAE; (United States), Journal Name: Trans. ASAE; (United States) Vol. 30:2; ISSN TAAEA
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
090122* -- Hydrocarbon Fuels-- Preparation from Wastes or Biomass-- (1976-1989)
140504 -- Solar Energy Conversion-- Biomass Production & Conversion-- (-1989)
ACETIC ACID
AGRICULTURAL WASTES
ALKANES
ANAEROBIC DIGESTION
ANIMALS
BACTERIA
BIOCONVERSION
BUTYRIC ACID
CALIBRATION
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CATALYSIS
CHALCOGENIDES
CHEMICAL ANALYSIS
COMPARATIVE EVALUATIONS
CORRELATIONS
DATA
DIGESTION
ELEMENTS
FUNCTIONAL MODELS
HYDROCARBONS
HYDROGEN
INFORMATION
INHIBITION
KINETICS
MANAGEMENT
MANURES
METHANE
METHANOGENIC BACTERIA
MICROORGANISMS
MONITORING
MONOCARBOXYLIC ACIDS
NONMETALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC WASTES
OXIDES
OXYGEN COMPOUNDS
PARAMETRIC ANALYSIS
PERFORMANCE
PROCESSING
PROPIONIC ACID
QUANTITATIVE CHEMICAL ANALYSIS
QUANTITY RATIO
REACTION INTERMEDIATES
REACTION KINETICS
SUBSTRATES
TOXICITY
USES
WASTE MANAGEMENT
WASTE PROCESSING
WASTES