Improvement of waste management system.
Currently, municipal waste from residents and small businesses in the Alytus region is collected and delivered to Alytus region landfill. After building the planned mechanical and biological waste treatment facility, all the collected mixed municipal waste will be co-fed into a mechanical-manual sorting line, and after that into the collection bunker. The bulky, non-combustible and hazardous waste will be separated out and the rest of the waste is directed to a shredder with a chipper where it is ground to 300 mm before reaching the initial sorting stage (drum separator).
The fraction from 20 to 80 mm separated by the drum separator consists of a large proportion of biodegradable waste – up to 70–80%. This waste fraction passes through a metal separator and goes to the biological treatment facility (dry anaerobic digestion and filtering with a bacterial mixture).
The next step will be improving the dry anaerobic digestion using microorganisms in the fermentation process. For this purpose, water mixed with bacteria is passed through the fermentable medium. The dry fermentation process consumes very little water. The following steps are the gravity drainage of technical compost and its homogenisation in tunnels. The compost is then treated mechanically in the drum separator – separating the small fraction of compost and the lighter fraction of SRF (raw fuel from waste).
It is planned to install 10 tunnels, including 2 reserve tunnels. This means that approximately 30,000 t of the biodegradable fraction of municipal waste can be treated in the fermentation tunnels. It is estimated that about 100 to 120 m³/t of biogas is released from the biodegradable fraction of municipal waste (depending on the composition). This means that about 1.5 million m³ of biogas (4,100 m³/d, 171 m³/h) can be produced per year. The biogas will be used to produce electricity (35–38%) and heat (40–50%). Theoretically, it is estimated that approximately 5.5 – 6 kWh of energy can be produced from of 1 m³ of biogas (with some of the methane coming from biogas).
Expected outcome
Improvement of waste management system: Currently, 61,000 t of municipal waste is treated in the Alytus region landfill. It is planned that after the MBT facility starts operating in 2013, the total amount of mixed municipal waste treated will increase to 63,800 t per year. By 2020, the amount of municipal waste entering the mechanical biological treatment may be increased up to 78,500 t/yr. To handle this amount of municipal waste treatment, mechanical biological productivity must be 25 to 27 t/h.
