Turning organic waste into biogas and high-quality compost: the process

The process integrates dry anaerobic digestion and composting in several steps:

• Pre-treatment of organic waste
  The organic fraction is reduced to particles smaller than 40 mm. Large materials such as plastics and textiles are removed or shredded. Metals can be recovered for recycling, while inserts such as stones and glass are eliminated. Cleaner feedstock simplifies the pre-treatment stage.
• Mixing and preheating
  The pulped organic material is mixed with previously digested residue from the digester, typically at a ratio of 1 tonne of  feedstock to 6–8 tonnes of digested material.
• Dry anaerobic digestion
  The mixture is pumped into the top of the digester. Inside the reactor, the material slowly moves downward by gravity while microorganisms break down the organic matter and produce biogas, which is collected and treated.
• Digestate extraction and recycling
  The largest part of the digested material is removed from the bottom of the digester and recycled back into the mixing stage. The average retention time in the digester is about 20 days.
• Composting stage
  The remaining digestate is transferred directly to aerated composting tunnels, where it is mixed with structural green waste to improve aeration and moisture balance. During this stage, the material undergoes aerobic stabilisation and maturation, producing high-quality compost.

The final product

The resulting compost meets VLACO certification standards, which ensure strict requirements for stability, maturity, contaminant levels and nutrient content. This guarantees a safe and reliable soil improver suitable for use in agriculture and landscaping.