Study on the Factors Influencing Methane Productive Rate of Cattle Manure Anaerobic Fermentation from 20 °C to 30 °C

The influence of liquor concentration, temperature and sludge amount on methane productive rate of cattle manure anaerobic fermentation from 20 degrees C to 30 degrees C were studied with the experimental design of quadratic rotatable regression. The ranges of liquor concentration, temperature and sludge amount were from 4% to 12%, from 20 degrees C to 30 degrees C and from 0% to 40% respectively. Frequency analysis was used to find the optimal experimental parameter space. The parameter contribution ratio was used to analyze the order of every parameter in quadratic nonlinear model. The single-parameter analysis was used to analyze the influence of every parameter on methane productive rate. The results showed that the optimal experimental parameter space of liquor concentration, temperature and sludge amount were from 7% to 9%, from 26 degrees C to 28 degrees C and from 21% to 30% respectively. The effect of temperature on methane productive rate was the greatest, sludge amount and liquor concentration were the second and third effective ones. The methane productive rate first increased and then decreased with increasing liquor concentration, first decreased and then increased with raising temperature and first increased and then decreased with increasing sludge amount.