III P

Anaerobic digestion as a natural process enables the re-entering of organic materials into the environ-mental cycle. As an industrial proc-ess it can be helpful to solve prob-lems of environmental pollution and recovery of natural ressources but needs special efforts for stable and effi cient operation. The process design and economic effi ciency of biogas plants is primarily related to the possible accuracy in prediction of biogas yields from or-ganic compounds and waste com-positions. With the help of experi-mental results and the analytical de-scription of complex organic com-pounds it is possible to develop models of energy and mass balances for the digestion of wastes like ma-nures or sewage sludge as well as heterogeneous bulk biowastes. Process design and plant economy are discussed for the full-scale ap-plication of a thermophilic anaerobic digestion system applied for the processing of farm manure and in-dustrial organic wastes as well as agricultural crop residues. This co-fermentation approach re-sults in enhanced biogas generation which is used for electrical and ther-mal energy production to meet the plant consumption and in addition enables use of the CHP-waste heat for farm and residential heating at the plant location while surplus of electric power is sold to the public grid. By the references of numerous plants in operation mainly in Europe full-scale manure digestion is shown to be a proven and reliable technol-ogy