New construction of an intake for leftover food at the Appenzeller WWTP
In the first half of the year, a collection point for leftover food was installed in a newly created annex between the Ökohof recycling centre (literally the “Ecology yard”) and the Appenzell wastewater treatment plant.
Food leftovers are delivered to the plant by restaurants in standardized containers. The containers are emptied into the receiving funnel with the aid of an automated tipping device. Then, the substrate is shredded and unwanted matter is removed. From there it is conveyed into a (stackable-type) storage tank, and fed in batches as a co-substrate to the digestion tanks of the sewage treatment plant. In this way, biogas can be obtained from the leftover food via the biological degradation processes. The portion of the undigestable co-substrate will be disposed of together with the digested sludge.