1 Introduction
Anaerobic digestion of organic wastes and by‐products from agriculture and the food industry is a process
known for many years and is widely used for waste stabilization, pollution control, improvement of
manure quality and biogas production (Weiland, 2006). Biogas production from manure contributes to
climate protection by reducing emissions of CO2 via substitution of fossil fuels and by reducing CH4
emissions from the manure during storage (Moller et al., 2007). It is expected that biogas production will
be instrumental in reaching European goals in the field of renewable energy. Due to the simultaneous
advantages of avoiding greenhouse gas emissions and producing energy (Sommer et al., 2004) as well as
reducing odor emissions (Hansen et al., 2006), there has been a rapid development in the use of biogas in
recent years (Weiland, 2006).
