Dry batch process

Product Description

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:

• Less dependency on mechanical equipment
• Not sensitive to undesirable substances such as stones, pebbles, strings, wood
• Reduced liquid consumption
• Reduced maintenance costs over 15 years
• Low energy consumption
• Ease of operation, traceability, batch, operation
• Use of raw solid digestate, spreadable as it is without specific treatment