(best examples and good practices) on household organic waste ...

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Figure 41.: Stockholm concept
(Chemical Engineering <strong>and</strong> Technology department KTH., 2007)
The Henriksdal WWTP was built in the 1940s <strong>and</strong> it is, as well as the digesters,
mainly located inside a rock. The upgrading plant is placed on the top of the
rock. The plant was built inside the rock due to the risks for bacteria <strong>and</strong> odor
diffusion, since there was a mill located not far from the area. A residential area
is located on top of the rock. The safety distance for localization of a biogas
plant is 50 meters from residential buildings <strong>and</strong> premises hard to evacuate,
such as schools, hospitals etc.
The external organic material received at the plant is as mentioned earlier
grease trap removal sludge <strong>and</strong> small amounts of other pumpable organic waste
from restaurants, institutional kitchens <strong>and</strong> market halls. The sludge is
transported to the plant by special slurry exhauster vehicles <strong>and</strong> since the plant
is located within the city of Stockholm, the distance is not very long. The
central location also facilitates a future possibility of household waste
treatment at the plant. The produced gas is upgraded at each plant <strong>and</strong>