What Is Anaerobic Digestion of Food Waste?

Anaerobic digestion (AD) of food waste is a natural biological process where organic waste breaks down inside oxygen-free, sealed tanks. Naturally occurring microorganisms consume the food material, converting it into two outputs: biogas (a renewable source of energy) and digestate (a nutrient-rich bio-fertiliser).

When you outsource your food waste to ReFood, your scraps, surplus ingredients, and leftovers are never discarded or dumped in landfills. Instead, they enter a tightly controlled, circular processing system that captures 100% of the energy and nutrients within your waste. Nothing is wasted.

How the Anaerobic Digestion Process Works (Step-by-Step)

Step 1: Secure Collection & Transport

Food waste is collected from your site in dedicated, clean containers, ranging from wheelie bins to bulk trailers, and transported directly to our specialised UK processing hubs. All operations fully comply with Animal By-Products (ABP) Category 2 and Category 3 regulations, ensuring complete regulatory assurance and chain-of-custody tracking.

Step 2: Depackaging and Pre-Treatment

Upon arrival, packaged food waste goes through automated depackaging technology to separate food from plastic, cardboard, or glass. The raw food is blended into a consistent liquid slurry, pasteurised to eliminate pathogens, and fed into sealed digestion vessels.

Step 3: Biological Breakdown (Digestion)

Inside these oxygen-free vessels, natural bacteria break down the organic matter over several weeks. As the microorganisms consume the waste, they release biogas (primarily methane and carbon dioxide).

Step 4: Capture & Resource Recovery

The biogas is captured from the top of the tank to generate renewable power, while the pasteurised organic liquid left at the bottom is recovered as high-grade agricultural fertiliser.

What Happens to the Energy Captured From Your Waste?

Rather than relying on a single recovery route, ReFood operates a flexible multi-facility model across the UK. This allows us to maximise energy recovery and support the nation’s transition away from fossil fuels in two distinct ways:

Renewable Electricity Generation

At facilities like our Doncaster hub, captured biogas powers combined heat and power (CHP) engines. The resulting green electricity is exported directly to the national grid to power local homes, businesses, and manufacturing facilities.

Gas-to-Grid Biomethane Injection

At our gas-to-grid facilities in Widnes and Dagenham, biogas is purified into high-quality biomethane. This renewable gas is injected straight into the national gas grid, supplying sustainable heating fuel to homes and heavy industry.

What Happens to the Solid Material? (Closing the Loop with ReGrow)

Energy generation is only half the story. The liquid material remaining after digestion contains all the vital plant nutrients, nitrogen, phosphate, and potash, originally taken from the soil.

ReFood converts this remaining material into ReGrow, our proprietary PAS110-certified bio-fertiliser.

PAS110 Certification

This independent British standard certifies that ReGrow meets strict safety, quality, and environmental requirements, legally transforming your waste into a certified agricultural product.

Soil Health Improvement

ReGrow is applied directly to farmland, replacing chemical synthetic fertilisers, enriching soil biology, and feeding future crop yields.

This completes a natural closed-loop cycle: growing food, capturing waste, generating power, and returning nutrients to grow the next harvest.

Why ReFood? The Traceability Advantage

While many commercial waste brokers can collect your bins, few can guarantee where your waste goes or how it is processed. Here is how ReFood provides a level of operational security unmatched in the UK waste sector:

• Complete End-to-End Ownership: ReFood operates its own dedicated collection fleet, regional transport hubs, and processing network. We manage the entire chain from the moment our driver collects your bin to the final injection of gas or application of fertiliser.
• National Processing Scale: Processing 480,000 tonnes of food waste per year across our purpose-built sites makes ReFood the second-largest dedicated food waste processor in the UK, guaranteeing your business long-term operational capacity.
• Local Closed-Loop Innovation: At our Doncaster facility, waste heat generated during digestion is piped directly back to local regional industry, including our sister company Nortech Foods. This creates a hyper-local, industrial symbiosis where food processing waste directly fuels regional food production.
• Decarbonised Logistics: We are actively transitioning our collection fleet toward a fully renewable energy fleet by 2035, ensuring that the transport of your waste reduces emissions at every step.

Answers to Common Business Decision-Maker Questions

How does anaerobic digestion improve our ESG and sustainability reporting?

Diverting organic waste from landfills prevents the release of fugitive methane, a greenhouse gas 28 times more potent than carbon dioxide. ReFood provides clear traceability metrics, giving your sustainability team audited data to report measurable Scope 3 carbon reductions and demonstrate true circular economy practices.

Will outsourcing food waste collection disrupt our daily operations?

No. ReFood designs waste collection workflows around your site layout and production schedules. We provide tailored container options, from kitchen caddies and wheelie bins to specialised bulk trailers and liquid tankers, ensuring seamless hygiene compliance and minimal staff operational burden.

Partner with the UK’s Food Waste Specialists

Diverting your food waste away from disposal and into renewable energy is one of the fastest, most effective steps your business can take to hit net-zero targets and lower waste management expenses.

Ready to transform your food waste into renewable energy and sustainable bio-fertiliser? Enquire about our commercial food waste collection services today or call our Doncaster team directly to get a tailored collection quote for your site.

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