Decontaminating Anaerobic Digestion feedstock

Recycling plastic packaging contaminated with residual food waste

Funded by the second round of the Ecosurety Exploration Fund in 2022, the RE:Solve project is tackling a significant but little-known problem. Large quantities of packaging are separated from food waste during processing at Anaerobic Digestion (AD) plants, but is too contaminated with food waste itself to be recycled. Ultimately it ends up in landfill where the attached food decomposes to release greenhouse gases. Led by South West College in Northern Ireland, the project is developing a new process to efficiently separate food waste stuck to plastic packaging, meaning both can be properly treated and recycled.

A huge contamination issue

AD plants turn food waste into energy. Some food waste arrives packaged and is first sent to a de-packer unit to remove the packaging. The machines do a good job, but the plastic packaging is left with a sticky residue from the food waste, which makes it hard to recycle. This is not a small-scale problem either - large AD plants can produce up to 10,000 tonnes of this material per year.


A lose-lose situation

It’s a messy problem. The food contaminated plastic is difficult to recycle without extensive cleaning which requires large quantities of water that make the process uneconomic.

If the contaminated packaging is landfilled the food waste residue decomposes releasing methane, which is more than 25 times more potent as a greenhouse gas than carbon dioxide, and the plastics are not recycled.



A separation solution

Funded by the Ecosurety Exploration Fund, South West College in Northern Ireland is developing a new process to efficiently and mechanically separate food waste residue from plastic packaging waste produced by anaerobic digestion plants, without using huge quantities of water.


Once separated, both the food residue and plastic can be effectively treated and recycled. Developing a process to remove the residual food waste will provide clean plastic for use in existing markets for recycled plastics and boost renewable energy production from anaerobic digestion plants by maximising the usage of food waste feedstock. Ultimately, it promises additional greenhouse gas reductions and increased sustainability.

plastic waste recyclingBOSS 2D sorted plastic film

Granville Ecopark

Scaled up success

This funded project will allow South West College to achieve proof of concept with a prototype plant at Granville Eco Park, a market-leading anaerobic digestion plant in Northern Ireland. This in turn will enable the process to be scaled up commercially, so it can be used by any anaerobic plant in the future.



"Not only do we hope to solve the packaging and food waste problem to aid local industry, but we hope to provide a solution for any AD plants that deal with food waste feedstock." Ashlene Vennard Photo Ashlene Vennard Renewable Engine Post Doctoral Researcher at South West College

About South West College

South West College is renowned for sustainability and renewable energy, notably through their Centre for Renewable Energy and Sustainable Technologies (CREST) – which provides assistance to business and research projects using its in-house expertise and suite of analytical test equipment. The College is the lead partner on the Renewable Engine project; a unique cross-border research and innovation (R&I) ‘supercluster’ involving internationally recognised partners in the area of renewable energy and advanced manufacturing technologies and sustainability.
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Enabling tomorrow's solutions

The RE:Solve project has been funded by the Ecosurety Exploration Fund which is investing £1million in projects that aim to reduce the environmental impact of packaging, batteries or WEEE through innovation or research in the UK. The fund is the first such opportunity to be launched by a UK compliance scheme. It builds on Ecosurety’s experience in supporting innovative projects and new technologies across the waste and recycling sector.
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