The FITEC Wet Anaerobic Digestion process is ideal for the processing of low to medium contaminated organic waste (e.g. food processing waste, residential & commercial SSO). The FITEC system removes contaminants & impurities (e.g. plastic packaging, glass, metal, bones etc. ) in three stages resulting in a clean digestate:
STAGE I: PRE-CLEANING
In the first step the waste is crushed (conditioned) and – if necessary – is mixed with process water to a medium dry matter content below 25 %. Afterwards most of the impurities (~ 80 %) are separated by the Biosqueeze, hydraulic separation press. For a maximum separation performance the impurities are heated up to 70 °C and then squeezed again. The separated impurities with a dry matter content of more than 50 % could be composted, dried or disposed.
The separated fluid or slurry is then sanitized, if required by local regulations, by the FITEC double tube heat exchanger (1 hour at 70 °C) and then distributed to one or several digesters by the FITEC KV Ball Valve pump. In the digesters, biogas is produced out of the digestible fractions. The biogas is used for the production of heat and power by a combined heat and power plant.
STAGE II AND III: FINE CLEANING
The second and third stage of the elimination of contaminants takes place directly in the digesters. Through the biological degradation process, the inert solids aka “grit” (e.g. pieces of eggshells or glass, bone splinters etc.) sink and are deposited on the digester floor. The FITEC Self-Cleaning Tank has a floor scraping system that continuously cleans the digester floor and separates out the grit for disposal. Swimming/floating contaminants such as light plastics, cork, rubber or Styrofoam et.c are continuously removed from the surface of the digester column via the FITEC Skimmer system. This process ensures that no floating mat of contaminants build up in the digester and that all the digestate that is transported to the digestate storage tank will be clean of contaminants.