In practice, normally manure and energy crops are used to produce biogas. Through innovative reactor concepts problematic biomass such as straw, solid manure, grass clippings from landscape management can also be utilized for the production of biogas.
Biogas is mainly composed of CH4, CO2 and H2. It results from the microbial transformation of organic biomass under anaerobic conditions. The diversity of microorganisms results in a significant metabolic potential that is generally suitable for the utilization of all kind of biomass. Of particular interest is the use of hard-degradable organic material, but also of residual and waste materials from agricultural and biotechnological production.
The Continuous Stirred Tank Reactor (CSTR) is commonly used or for the combined fermentation of manure and biogas plants.
Digestation of structure rich materials demands for novel reactor types. Researchers at the ATB developed the Upflow Anaerobic Solid-State (UASS) Reactor as well as a continuous two-phase leach bed reactor (LBR). These reactor types are characterized by high biological stability. They are particularly suitable for bulkable long-fiber organic biomass. (See also Biogas laboratory)
Furthermore, methods for the elimination of nitrogen have been integrated into novel biogas plant concepts. As a result, it is possible to reduce nitrogen loads which are detrimental to microbiology. Such effects occur in particular when agricultural substrates such as chicken manure is used as feedstock.
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