1

WASTE PRETREATMENT

The pretreatment section allows the separation of the non-degradable waste fraction (plastic, wood, metal and inert waste), which could eventually be found in the organic waste transported to the plant, in order to avoid problems in the following anaerobic digestion phase and ensure the highest efficiency of the plant.

Pre-treated organic waste is then stored in a walking-floor feeding bunker through which it is transported to the digestor.

2

ANAEROBIC DIGESTOR

The digestor is continuosly fed. It designed as a horizontal piston flow reactor and it is equipped with eight paddle stirrers and a heating system with the possibility of operating in mesophilic (37 ° C) or in thermophilic (50 – 55 ° C) conditions.

3

DIGESTATE

The extracted digestate has a high water content so it is mixed with the green fraction, which is able to absorb water and give structure to the material: it is then sent to the composting phase.

A wheel loader deposits the green fraction in an external hopper of adequate capacity, able to automatically dose the material according to the quantity of digestate to be mixed.

4

UPGRADING

The refining of the biogas is done through a PSA technology system with chemical absorption of H2S and removal of CO2, N2, O2.

The PSA system allows a high efficiency of the treatment.

5

FEED-IN

The resulting biomethane is sent to the cabin of connection to the gas distribution network, which is composed by an analysis and measurement section, a filtration and pressure reduction section and an odorization system.

In the “fiscal measurement” part of the cabin, there are the gas analysis and fiscal flow measurement instruments and the valves for the deviation of the gas in the flare in case of overpressure or in case the gas doesn’t respect the specifications.

The filters, the pressure regulation section, the non-fiscal gas flow measurement and finally the odorization system are instead located in the “non-fiscal measurement and regulation” part of the cabin.