Transforming organic waste into energy and high-quality compost – the process
The process integrates wet anaerobic digestion, separation and composting in several steps:
- Hydro-mechanical pre-treatment
Organic waste is mixed with water in a pulper to create a homogeneous, pumpable suspension (around 90% water content). During this stage:- Organic material is broken down into fine particles
- Heavy impurities (e.g. stones, glass) settle and are removed
- Light impurities (e.g. plastics) float and are separated
The recovered water is reused within the system.
- Pulp cleaning and preparation
The suspension passes through a grit removal system, increasing the solids concentration to an optimal level for digestion. Excess water is recycled back into the process. - Wet anaerobic digestion (AD)
The prepared pulp is fed into the digester, where microorganisms break down the organic matter and produce biogas. Mixing inside the digester is achieved by recirculating biogas, creating strong internal currents without the need for mechanical stirrers. This ensures stable operation and reduces maintenance needs. - Digestate dewatering and separation. The digestate is separated into:
- A liquid fraction with low solids content
- A solid fraction (digestate cake) with high solids content
Most of the liquid is reused as process water, while the rest is treated internally.
- Composting stage
The solid digestate is transferred to composting (e.g. windrows or aerated systems), where it undergoes aerobic stabilisation and maturation to produce high-quality compost.
The final product
The resulting compost is a stable and mature soil improver, meeting high quality standards for biological stability. It can be safely used in agriculture and landscaping, contributing to soil health and nutrient recycling.