Envar Composting is able to undertake AD Grit Recycling, turning the waste into a soil improver. AD grit refers to the materials that cannot be broken down during anaerobic digestion and can accumulate in the systems. Grit in this context usually includes bones, seeds, fruit stones and any inorganic materials that can enter the AD system along with the organic feedstock.

The grit particles can cause issues by settling in the bottom of the digestion tank, reducing the efficiency of the system and potentially causing damage to equipment.

Currently, a number of biogas plants are Continuously Stirred Tank Reactor (CSTR) type AD plants. When first commissioned most were built without pre-treatment to remove unwanted materials. To deal with this, digestate tanks will need to be emptied and cleaned before material compacts and solidifies.

These materials will not compost under regular conditions, making responsible disposal difficult.

Envar composts the grit, in a mix along with food and green waste, through our in-vessel composting (IVC) technology before being arranged into open windrows. After 6-8 weeks the material is ready for screening and sorting to remove any inorganic materials. The result is peat free high-quality PAS 100 Soil Improver.

To find out more about AD Grit Composting services from Envar Composting...