Skellefteå Biogas Plant

The municipal biogas plant, situated at Tuvans wastewater treatment plant in Skellefteå, receives domestic waste, slaughterhouse waste and liquid waste.

The plant has three receiving vessels, of which two are for sourceseparated domestic waste and one for slaughtery waste. The vessels for domestic waste are equipped with four bottom screw conveyors each for decomposition and homogenisation of the incoming substrates and discharge to the transport conveyors for further transport to two mixers. In the mixers the substrate is diluted to the right DS concentration. From the mixers, the substrate is led to a bio-separator for separation of non-digestable material. After that the substrate passes through a disperser for further decomposition and is then led to the buffer tanks. The slaughtery waste is transported with a bottom screw conveyor to the disperser for decomposition and from there to the buffer tanks. Liquid waste is pumped to the buffer tanks via the disperser. From the buffer tanks the substrate is pumped to two hygienisation tanks where the substrate is heat-treated at 70 °C before it is pumped to the digester. To avoid too high temperature in the digester, the incoming substrate is cooled with the dilution water fl ow that is recycled to the process. The produced biogas is then upgraded to vehicle fuel.

Technical data

Organic domestic waste + reserve:

8 720 tons/year

Organic slaughterhouse waste:

5 500 tons/year

Other (liquid):

780 tons/year