Abstract: MATH/CHEM/COMP 2002, Dubrovnik, June 24-29, 2002

MATHEMATICAL MODELING OF ANAEROBIC BATCH FERMENTATION OF CATTLE MANURE

AT MESOPHILIC TEMPERATURE

Vahida Selimbasic, Ivan Petric, and Zehrudin Osmanovic

Faculty of Technology Tuzla, Univerzitetska 8, 75000 Tuzla, Bosnia and Herzegovina

In this paper, the anaerobic fermentation of high strength organic waste in batch reactors has been investigated. A mathematical model describing the degradation of cattle manure has been developed. Two different ratios of the cattle manure to water (the substrate dilution of 22.11% and 5% dry matter) with defined incubation times were investigated. Mesophilic anaerobic sludge was used as inoculum. Cattle manure was digested at 35°C for up to 50 days in air-tight 120 mL glass bottles. Three repetitions per both ratio of cattle waste were used. First order rate equations were used for initial hydrolysis of manure.
Monod kinetics, modified by the proper inhibition expression, was used to describe methanogenesis from acetate. Experiments data were used for calculation of corresponding kinetic parameters evolved in the model. Stoichiometry of anaerobic fermentation has been also established. For this dynamic model, solutions were approximated with corresponding numerical methods.

The model has been applied for the simulation of anaerobic mesophilic fermentation in batch reactors and results compare favourably with experimental data.

Key words: mathematical modelling, batch, anaerobic fermentation, mesophilic, cattle manure, simulation