Recycling plant for bio-waste and liquid manure [return to biogas plant in waste industry]

Please klick the images in order to get more information about the units.     The picture shows a modern fermentation plant for municipal wastes from GBU, Germany. The well fermented substrate is directly delivered to the farms as a substitute for mineral fertilizers or - as an option - might be mixed with structured material as straw, paper, rice shells etc. and be composted. The gas is gathered inside a pressureless gas holder and used for the production of electricity and hot water by means of a cogenerator.             Energy system   The hot water is partly used to heat up the biogas suspension and to maintain the reactor temperature, to heat up the evaporation plant and to heat up the granulation system.   Treatment of the fermented substrate   The further treatment of the fermented substrate mainly depends on local conditions, especially on the market for the final products.Therefore two alternatives are presented. Evaporation After decantation the solid fraction of the effluent is composted. The liquids are stored in a buffer tank where they are acidificated. After adjustment of the pH to about 6 they are concentrated by a specially designed fluidized-bed-evaporation plant up to a dry matter content of 30%. The concentrate is composted together with the solid fraction and the sorted out organics. There is no waste water from this process. Evaporation-Granulation After the treatment as described under "Evaporation" all of the material is dried and granulated in a combined granulation and drying plant. The final product is a dry granulate with a dry matter content of more than 90% which can be stored, handled and applied like a mineral fertilizer Since no dewatering station is foreseen, the need of electrical energy by the process is very low. Thus most of the electricity produced can be sold to the public network.