Plastic Circularity in Aquaculture – Mobile Shredder Trial
Mobile Plastic Recycling Trial with Oyster Farmers
- LEP23_015_LLC_9
The issue
Plastic is widely used in the oyster industry due to its durability and cost-effectiveness, but damaged or end-of-life infrastructure like baskets, trays, tags, and ropes often becomes difficult to recycle due to contamination (biofouling) and the bulky nature of the material. Many estuary-based oyster farms are located far from recycling centres, and contaminated or mixed plastic types are routinely rejected from standard municipal recycling streams. As a result, aquaculture waste often ends up stockpiled on farms, landfilled, or—if not managed properly—washed into estuaries during storm and flood events, contributing to marine plastic pollution and posing reputational risks to the industry.
The solution
To address the recycling gap, a mobile plastic shredder unit was trialled in partnership with local oyster farmers and Eyre Peninsula Plastics Recycling across 11 NSW estuaries. This trial aimed to:
- Provide on-site shredding of hard plastics to reduce waste volume and transport costs
- Improve recycling rates of aquaculture infrastructure
- Explore circular economy solutions for turning shredded plastic into new products
- Raise awareness of better end-of-life gear management
The mobile unit was transported between farms, enabling small-scale plastic processing directly at the source and increasing accessibility for remote or estuary-based operations.
The impact
Starting in Wonboyn, on the far South Coast of NSW, moving through multiple estuaries to finish in Nambucca Heads, covering the estuaries that expressed prior interest in a collection. Demand exceeded slots available, and the crew worked through two weekends to keep up. To get the gear ready for shredding, various treatments were tested, including pressure washing and manual removal of growth (e.g. barnacles).
While some material had to be removed because of screws, nails or timber and taken to landfill, importantly all material shredded was accepted by the processor in Sydney and on-sold. In this case the shred was on-sold to a third party and used in the manufacture of cable lining. This is a significant milestone on past comments that the material is too contaminated to be of value.
In total, about 32 tonnes of plastic waste was removed and recycled. This is equivalent to 30 truckloads or half a football field. A total of 11 estuaries were serviced with 40 farmers participating in the trial which is nearly 20% of the NSW industry.
Learnings
The trial provided critical first data on gear types, plastic quality, and contamination issues.
The value of the end product is highly dependent on the experience of the crew operating the shredder and prior screening and sorting of the material to ensure maximum value for processer and manufacturing can be maintained. Education around pre-sorting and cleaning gear is essential to improve recycling outcome.
From this trial, the value of the recycled plastic can cover the costs of freight and refinement but additional costs of logistics, processing the plastic before it can be shred etc. is still relying on grant funding or industry. While on-site shredding is effective, it requires a coordinated logistics model to keep the costs to a minimum.
As landfill costs continue to rise, recycling is becoming more economically feasible. Opportunities exist for value-adding shredded plastic into new aquaculture or marine products (e.g., tiles, tags, toolboxes).
Key facts
- 11 estuaries visited
- 40 farmers participated
- ~102 m3 of plastics removed (equivalent to 1/2 football field or 30 truckloads)