Anaerobic digestion turns your waste into resources

Anaerobic digestion (AD) is a biological process in which microorganisms break down organic matter in the absence of oxygen. This controlled decomposition produces biogas — primarily methane and CO₂ — along with digestate, a nutrient-rich byproduct used as a natural fertilizer. AD is widely used across agricultural, industrial, and municipal sectors as a proven renewable energy solution.

A wide range of organic feedstocks can be processed: agricultural residues (manure, slurry, crop waste), food industry byproducts, municipal organic waste, wastewater treatment sludge, and energy crops. The key requirement is that the material must be biodegradable. Mixed feedstocks are common and can actually improve biogas yields through co-digestion.

The two primary outputs are biogas and digestate. Biogas is a renewable gas composed mainly of methane (50–70%) and CO₂, which can be valorized as energy. Digestate is the stabilized organic residue remaining after digestion — it is rich in nitrogen, phosphorus, and potassium, making it a high-quality substitute for mineral fertilizers.

No. Biogas is a versatile energy carrier with multiple end uses. It can be combusted in a boiler to produce heat, used in a combined heat and power (CHP) unit to generate both electricity and thermal energy, upgraded to biomethane (renewable natural gas) for injection into the gas grid, or compressed as a vehicle fuel (bio-CNG/RNG). The right valorization pathway depends on your site’s energy needs and local infrastructure.

Partially, yes — and it’s one of the strongest arguments for AD projects. When upgraded to biomethane, biogas reaches natural gas quality and can directly substitute fossil gas in heating, industrial processes, or transportation. On a larger scale, widespread AD deployment contributes meaningfully to reducing fossil fuel dependency and meeting national renewable energy targets.

Not entirely — they are complementary technologies. Composting is an aerobic process suited for dry, fibrous organic matter and produces a soil amendment. Anaerobic digestion processes wetter, higher-energy feedstocks and generates both energy (biogas) and fertilizer (digestate). In many cases, digestate can be further composted after the AD process. Choosing between the two — or combining them — depends on your feedstock profile and energy objectives.

Significantly. AD reduces greenhouse gas emissions in several ways: it captures methane that would otherwise be released into the atmosphere from decomposing organic waste, it displaces fossil-based energy with renewable biogas, and digestate replaces synthetic fertilizers whose production is highly carbon-intensive. Life cycle assessments consistently show net GHG savings of 60 to 90% compared to conventional waste management and energy production.

A successful AD project relies on five pillars: a thorough feasibility study with accurate feedstock characterization, well-sized and properly integrated equipment (mixers, storage, gas treatment), a clear biogas valorization strategy aligned with your business model, regulatory compliance from permitting through to operation, and a long-term maintenance and monitoring plan. Partnering with an experienced technical integrator from day one is critical to avoiding costly delays or underperformance.

Digestate is a valuable co-product, not a waste stream. It can be applied directly to agricultural land as an organic fertilizer, providing crops with readily available nitrogen and other nutrients. It can also be separated into liquid and solid fractions for more targeted agronomic use or further processing. In all cases, digestate application is regulated and must comply with local spreading plans and environmental standards.