Estimation of methane production for batch technology – A new approach

• Proposed model calculates methane production with good precision.
• Model mainly uses only last phase – methanogenesis.
• Model uses only simple factors – for example content of carbon in the mixture of substrate and inoculum.
• Model was tested for arable crops, animal manure, vegetable waste, animal waste and municipal waste.

In the case of agricultural biogas plants it is the living microorganisms (mainly archaea) that determine the amount of methane produced. If the conditions in the digester are not adequate or the substrates are selected incorrectly, the microorganisms will not be able to develop properly and methane production will also be low or none. Therefore, in the first place the influence of individual factors on the production of methane was analysed. Next, based on the conclusions drawn from the analysis of the factors, a mathematical model was developed that will facilitate the selection of appropriate substrates and process parameters by future investors building agricultural biogas plants. The aim of the study was to demonstrate the impact of the factors on the production of methane and to present a mathematical model for estimating methane production for batch technology used in agricultural biogas plants (this kind of production is also used in laboratories for testing specific substrates). The model presented in the paper has been developed and tested on a group of over seventy substrates of agricultural origin. The inclusion of many factors determining methane production in the model is not complicated as each of the factors is easy to measure.