This technology has been proven for many years and is suitable for deposits with a high dry matter content, without the need for complex pretreatments.
The operation is simple: the waste to be treated is incorporated in digesters, commonly called “garages-digesters” and remain in fermentation for 6 to 8 weeks. During this cycle, the material is maintained at mesophilic temperature by means of a ground heating network system. Inoculation is by reincorporation of already digested material and by spraying heated percolate through the pile throughout the cycle. The percolate is then recovered via gutters and stored in a tank adjacent to the digesters.
The biogas produced in the various garages-digesters is stored using gasometers and then upgraded to cogeneration to produce electricity and heat. The continuous operation of the cogenerator is ensured by the filling of several digesters at regular intervals of time.
At the end of the anaerobic digestion cycle, the fermentation residue called digestate is discharged and can be spread as it is or undergo a composting or drying operation.
This technology can be adapted to feedstock quantities from 5 000 to 30 000 t/year and has the following advantages: