Colby Phillips Advisory was engaged by Grain Producers SA to review pathways for recycling plastic grain silo bags for its 4,000 members across South Australia. These silo bags are used as temporary storage for harvested grain and can hold several hundred tonnes, weigh 100+ kg and when unrolled be up to 100m long.

Grain silo bags in use

Waste grain silo bags

The study included grain farmer engagement, projection of silo bag waste generation across the State, engagement with regulatory authorities, potential recyclers and existing recycling scheme operators, ideation of potential recycling pathways, and modelling of potential costs and greenhouse gas emission reduction outcomes for each pathway.

It found that:

• South Australian grain farmers could generate between 500 and 1,500 tonnes of bag waste per year,
• A recycling scheme for the bag waste bags could cost from $60 to $300 / bag, depending on how the recycling scheme operated and how far away from a recycler the farmer was. 
• For many farmers, this recycling disposal cost would be > 10% of the typical bag supply cost.
• It could be several years before local recyclers were ready to accept the bag waste.
• There needed to be more engagement with farmers, bag suppliers, existing recycling scheme operators and recyclers to decide the best approach.

An action program was developed to help guide grain farmers towards future recycling of their waste silo bags.

A copy of this report can be viewed at: Grain silo bag circular economy feasibility study (greenindustries.sa.gov.au)