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Keenan Recycling recycles marine growth

Sea change for sustainability: Keenan Recycling and Liberty Industrial partner on marine growth recycling

Keenan Recycling, a leading food waste recycling and composting company, and Liberty Industrial, a global engineering, services, and industrial group, collaborated recently to showcase responsible decommissioning practices through the successful recycling of marine growth waste from a North Sea vessel.

A first for Keenan Recycling

Liberty Industrial contacted Keenan Recycling seeking a sustainable solution for marine growth removed during the decommissioning of a North Sea vessel. While Keenan Recycling processes over 2500 tonnes of shellfish waste annually, this marked their first encounter with this specific waste stream. Recognising the growing need for such solutions, Keenan decided to explore the opportunity.


Keenan Recycling recycles marine growth
Keenan Recycling recycles marine growth

A collaborative effort

Risk assessment and regulatory approval

Keenan Recycling conducted a thorough risk assessment to ensure the marine growth wouldn’t negatively impact the composting process or the final product. Following a sample analysis and confirmation of minimal contamination, the next step involved securing regulatory approval. As the specific waste category wasn’t listed on Keenan’s existing permit, special permission from SEPA (Scottish Environment Protection Agency) was required. This involved categorising the waste according to the European Waste Catalogue and obtaining approval for a trial basis.

The composting process

Keenan Recycling utilises the state-of-the-art in-vessel composting system at the New Deer facility. The process involves:

  • Shredding: The marine growth is shredded to create a homogenous mixture with increased surface area for microbial activity.
  • Blending: The shredded growth is combined with garden waste and oversize woody material to achieve the optimal composting blend, ensuring proper nitrogen content, moisture, and oxygen levels.
  • In-vessel composting: The mixture is loaded into vessels where natural microbial activity breaks down the organic material, generating heat and sanitising the waste.
  • Maturation and screening: Following the initial composting phase, the material undergoes maturation and screening to remove larger pieces and any plastic contaminants.
  • Final product: After a final maturation period, the composted material meets BSI PAS 100 standards, transforming it from waste to a valuable soil improver.

18 chamber Vertical Composting Unit (VCU) system at the New Deer site

Benefits of recycling marine growth waste

  • Environmental advantages: Recycling diverts organic waste from landfills, promoting sustainability and reducing methane emissions.
  • Agricultural applications: The resulting compost boasts beneficial properties for local agriculture. Rich in nutrients like N, P, and K, it increases organic matter, improves soil biodiversity, and acts as a natural liming agent, potentially reducing reliance on chemical fertilisers.

Looking ahead

Both Keenan Recycling and Liberty Industrial are committed to responsible waste management practices. This successful collaboration demonstrates the viability of recycling marine growth waste while contributing to a more sustainable future. Moving forward, improved communication regarding waste type, quality, and origin will further optimise the processing experience.

“It was very pleasing to be able to provide an outlet for this waste stream though as I hate to see any organic waste getting landfilled. It’s vitally important that there are alternatives from an environmental perspective but also as there will be a complete ban of biodegradable waste to landfill at the end of next year,” says Gregor Keenan, Operations Director at Keenan Recycling.

“Going forward, we really just need to know what we’re getting in terms of the waste type, quality, where it’s from and when it will be delivered. Last year we processed over 105,000 tonnes at our New Deer site so there’s a huge amount of admin involved for a relatively small team,” adds Gregor.

Keenan Recycling is a leading composting company committed to diverting organic waste from landfills and transforming it into valuable resources. The in-vessel composting process utilises natural microbial activity to create high-quality compost for agricultural use.

“This collaboration with Keenan Recycling showcases our commitment to finding innovative and sustainable solutions for decommissioning waste. Recycling the marine growth demonstrates the potential for responsible waste management in the industry, while creating a valuable resource for agriculture. We look forward to working together on future projects to minimise our environmental impact,” says Lawrence Henderson, Project Director – Decommissioning, at Liberty Industrial.

Liberty Industrial is an award winning, international deconstruction and remediation contracting business. They have carried out some of the largest and most complex projects in mining, oil and gas, energy and defence sectors.