Challenge 11.3

What is the problem, and how does it affect the Challenge Sponsor organisation, service users and/or People of Scotland?

Litter Sinks develop due to a combination of factors such as tides, currents, and prevailing winds. These can cause marine borne plastics and litter to accumulate unevenly along our coastlines. As plastics break up in the environment, smaller and smaller pieces of mixed plastics become heavily intermingled with seaweeds, and then can become embedded in matrices of wrack, grasses and other plant matter.

The quantity of litter at Arrochar over the decades built to the point where it was designated a Litter Sink by the Scottish Government in 2017 and heavy machinery was required to remove / transport it to landfill. It is extremely heavy and therefore costly to dispose of.

Whilst on the foreshore, this litter accumulation is an environmental hazard that can cause animals, marine life and wildlife to become entangled and in some cases they can ingest the litter as well, causing a build-up of toxins in the food chain (toxins adhere to micro plastics). Further, the Litter Sink materials generate methane once in landfill, and the mixture of plastics and biodegradable material poses real challenges in relation to removal and separation. Scotland is moving towards a ban on sending biodegradable materials to landfill from January 2026, and so mechanical methods of clearing the Litter Sink would become even more challenging using the current available approaches.

The challenge also has a detrimental effect on the Local Community and visitors to the area. The Arrochar Litter sink is often in the media, and is considered by many to be a blight on the landscape at the heart of a small rural west coast village. The local community have tried to tackle the worsening litter problem for decades, however it is completely disheartening, watching waste arrive on every tide and not being able to make a visible difference.

The community can no longer landfill the waste (which was already a large and cost-prohibitive exercise), and it can’t be left in situ to continue to worsen. This is why we present this Challenge – to seek new and innovative ways to combat this problem for the benefit of the Local Community, tourists, economy and environment.

We are excited to partner with The National Robotarium in this Challenge. Pending the nature of the proposed solutions, the Robotarium may be able to provide connections to support, subject-matter expertise and robotics specific commercial expertise, to participants.

How will we know the Challenge has been solved?

• We see an end to the tons of marine plastics washed up on the shore with every tide.

• Arrochar once again becomes a place where the local community can be proud of their village with the loch reverting to becoming a scenic focal point for locals and visitors alike.

• Improved quality of life for local people and an enhanced visitor experience.

• We see an increase in economic activity both in terms of opportunity for those making their living in or on the water eg aquaculture and tourism.

• We see increased inward investment eg. tourism infrastructure and an increase in tourist numbers.

• The reverse of business decline and boost to local employment

• We see a reduction in the threat of invasive non-native species (INNS).

• Improved  biodiversity.

• Environmental benefits such as a reduced risk to wildlife.

• There is potential for recycling the plastics removed.

• There is potential for use of the seaweed once separated from the plastics.

Who are the end users likely to be?

• Argyll & Bute Council (+ other Local Authorities with coastal areas)

• The GRAB Trust

• Marine Directorate

• Land owners

• Entrepreneurs/businesses who lead the development of a successful technological solution that can be replicated around the UK and abroad in locations experiencing similar problems.

• Harbour / port owners

• Community groups

• UK and Foreign Governments

Has the Challenge Sponsor attempted to solve this problem before?

Only through directly organising / supporting volunteer beach cleans.

Technology exists to remove marine litter from the open ocean (The Ocean Cleanup) where the vast majority of what is removed is marine grade plastics coming from offshore industries. However what works in large, open bodies of water doesn’t necessarily work in smaller, inland bodies of water.  We also have solutions for the mouths of rivers where we have one directional flow of water. (This is also carried out by the ocean cleanup with their interceptors). In other locations booms are used – one is proposed for the Clyde by the City of Glasgow (New River Clyde Boom to Net Marine Litter - Glasgow City Council) – though this is currently unfunded. In calm, flat bodies of water (such as marinas and canals) where there is access to power – sea bins can work well. As it stands there is no existing technology that we are aware of for removal of the litter from a tidal sea loch where the litter is heavily mingled with large amounts of seaweed.

Anaerobic digestion has been ruled out previously as a solution. Zero Waste Scotland (ZWS) administered an Innovation fund through their Circular Economy Investment Fund and Waste Prevention Implementation Fund.  There were exceptionally few applications.  The business that applied for funding to look at the potential for using anaerobic digestion of the Arrochar waste, applied and received a very small amount to run laboratory trials - with a view to scaling the application up should the trials have been successful.  This was pursued by the applicant as a potential new business opportunity – looking for economic/commercial potential. The business liaised with the waste experts in Zero Waste Scotland regarding their trial and outcomes and did not apply for further funding, concluding that as a consequence of the level of plastic contamination anaerobic digestion at scale was not economically viable.

Are there any interdependencies or blockers?

No.

Will a solution need to integrate with any existing systems / equipment?

No.

Is this part of an existing service?

No.

Any technologies or features the Challenge Sponsor wishes to explore or avoid?

We are open to a broad range of technologies that can solve this Challenge, but we are particularly interested to see approaches that utilise advances in robotics. This is not a requirement of the Challenge however — the most important thing is solving the problem.

What is the commercial opportunity beyond a CivTech contract?

In 2024 globally, we generated around 220 million tons of plastic waste. This figure continues to increase. Of this around 70 million tons, is expected to be mismanaged and end up in the natural environment. Sadly Arrochar is not unique in its marine plastic problem, on many beaches around our coastlines we find mixtures of materials which are unable to be separated by hand.

Who are the stakeholders?

• The GRAB Trust

• Local Residents (Arrochar Community Council)

• Argyll and Bute Council – land owners

• Luss Estates –  landowners

• Crown Estates – if any offshore structure was being proposed

• LLTNP – Arrochar falls within the National Park

• The National Robotarium

Who’s in the Challenge Sponsor team?

• The GRAB Trust – BMLP

• SSE

• Sea Changers

• Loch Long Salmon

• The Arrochar Community Council

What is the policy background to the Challenge?

Marine litter strategy - gov.scot (www.gov.scot)

Biodiversity strategy - Biodiversity - gov.scot

Climate change - gov.scot

Following publication of the Arrochar Litter Sink topic sheet arrochar-litter-sink.pdf (www.gov.scot), the Scottish Government has supported Keep Scotland Beautiful’s Upstream Battle – focusing on changing littering behaviour along the Clyde and its tributaries to reduce amount of litter ending up in our seas and washing up on our beaches. Unfortunately the litter/waste continues to arrive and accumulate.