- Wet pre-treatment of waste with separation of the contaminants and production of a pumpable suspension
- Sand separation by a hydrodynamic grit removal system
- Digestion of the suspension in the methanogenic stage
- Solid-liquid separation of the fermented suspension; recirculation of the filtrate as process water and production of anaerobic compost
An essential part of the development is the wet pre-treatment of waste. The central component of the wet pretreatment is the waste pulper. Scheme 1 is showing the material streams around the waste pulper. The waste which undergoes particle size reduction is intensively mixed with recirculated process water and thus dissolved and further disintegrated. The arising suspension is withdrawn through a sieve at the pulper bottom to be subsequently fed into the hydrodynamic grit removal system. After the withdrawal of suspension the pulper is partly filled with process water again for the contaminant separation. The cleaned contaminants are separated by a rake and a heavy fraction trap. Thus the streams of the rake and heavy fractions are arising. The rake fraction is pressed to get dewatered and transferred to a landfill or to an incineration plant. The heavy fraction is classified for further reduction of organic contents and can be used, for example, as filling material for road construction. Finally, there is a reducing of the wet mass of the waste of clearly more than 90 %.