Semi-permeable membrane windrow composting of green waste

This technology transforms green waste and digestate into high-quality compost through an aerated windrow composting system covered with a semi-permeable membrane. It is designed to process plant-based materials from gardening and landscaping, while also allowing the addition of digestate to optimise moisture and nutrient balance.

The controlled process ensures efficient decomposition and the production of a stable, hygienised and nutrient-rich soil improver.

Producing high-quality compost from green waste – the process

The process combines pre-treatment, aerated composting and refining in several steps:

  1. Feedstock reception and preparation
    Green waste (branches, leaves, grass, woody materials) and, when needed, digestate are collected and prepared for processing.
  2. Shredding and screening
    The material is reduced in size and cleaned to ensure a consistent structure for composting.
  3. Windrow formation on aerated floor
    The prepared material is arranged in windrows placed on an aerated floor system, allowing controlled air supply.
  4. Membrane covering
    Windrows are covered with a semi-permeable membrane, creating a stable microclimate that protects against weather and supports efficient decomposition.
  5. Active composting (hygienisation phase)
    Air is supplied from below, maintaining oxygen levels and thermophilic temperatures required to eliminate pathogens and ensure hygienisation.
  6. Curing and stabilisation
    After the active phase, the material continues to mature and stabilise.
  7. Membrane removal and screening
    The membrane is removed and the compost is screened to achieve a uniform product.
  8. Product refinement and storage
    The final compost is refined and stored for use.

 

The final product

The compost produced meets recognised quality standards, ensuring it is safe and suitable for agricultural use.

Typical characteristics include:

  • Organic matter content and stable humus
  • Balanced nutrient levels (nitrogen, phosphorus and potassium)
  • Neutral to slightly alkaline pH
  • Absence of pathogens, viable seeds and significant impurities

This makes the compost suitable for soil improvement in agriculture.

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