2 July 2018 by Elizabeth Slow

Food recyclers defend use of plastic bags

Organics recycler Agrivert has promoted the benefits of using plastic bags as caddy liners as a way of increasing food waste recycling.

The news comes after the Waste Partnership for Buckinghamshire reported a surge in food waste recycling last month after allowing some residents to use plastic bags as opposed to compostable liners (see letsrecycle.com story).

Agrivert’s Wallingford anaerobic digestion facility

The move could be considered controversial given the current momentum around plastics and growing public awareness on single-use materials. There have also been calls from some in the sector for better quality across the whole supply chain, which may include prohibiting the use of plastic liners (see letsrecycle.com story).

Agrivert is one of two companies contracted to manage food waste for Buckinghamshire at its Wallingford anaerobic digestion facility. The other company is Olleco at its Westcott Park facility (acquired from Renewi).


Speaking to letsrecycle.com, Harry Waters, commercial director at Agrivert said that allowing material to be presented in plastic bags helps to remove public barriers to recycling food waste. And, Mr Waters using plastic bags removes “one of the five biggest barriers to recycling which is price”.

According to Mr Waters, bioliners are around five times the price of plastic liners and less available, therefore they are expensive for residents to purchase.

Agrivert is also able to remove plastic bags “much more efficiently,” he explained, as bioliners become “gloopy” during the anaerobic digestion process and difficult to separate.

The company has made investments in secondary screens for digestate to improve quality. “We have upgraded all of our plants and put in secondary screens for the digestate to retrieve the smallest bits of plastic,” Mr Waters said.

A sample of the digestate produced at one of Agrivert’s AD plants

“Some plastic inevitably can still end up in the digestate although it is a very small amount,” says Mr Waters. However, he says his view is that the overall benefits of digestate as a fertiliser and the increase recycling is likely to outweigh the potential “tiny fragments” of plastic which might get through.

The change is also designed to increase “transparency” to the public who may believe their bioliners are being recycled, he said. Both bioliners and plastic bags removed during the process are sent for energy from waste.

And, Mr Waters said the company has been “very focussed” on digestate quality. “Despite already meeting PAS110 we upgraded our screening systems prior to the very welcome intervention of Blue Planet which raised awareness of plastics in the environment.  We are only able to work with partners like Buckinghamshire because we have comprehensive systems in place.”


Meanwhile, Olleco has explained that its Westcott Park facility can accept “limited amounts of plastic or compostable/biodegradable liners”.

The AD plant receives food waste from Aylesbury Vale district council in Buckinghamshire. Residents in the district have been allowed to use plastic bags as caddy liners since the start of June 2018.

A spokesperson for Olleco said the de-packaging technology at Westcott Park “ensures materials such as plastics and compostable liners are removed from the food waste during this part of the process”.

The facility has gained and maintained its PAS 110 certification for digestate, Olleco said.

Olleco’s Westcott Park AD facility receives food waste from Aylesbury Vale district council

Despite some organics recyclers continuing to accept material collected in plastic liners, environmental campaigners remain opposed to the use of the material for the collection of food waste.


In response the use of plastic bags as caddy liners, Julian Kirby, plastics campaigner for Friends of the Earth (FoE), pointed to the need to stop using plastic bags in the future.

“An increase in food waste collection is clearly beneficial, and a bonus would be if this scheme collects plastic bags to be recycled, or otherwise disposed of properly, which is to say, not incinerated,” he said.

However, Mr Kirby explained: “In the long term we have to overcome our collective plastic addiction by finding ways to drop plastic bags altogether.”


I’m interested to note FoE’s Julian Kirby’s comments here, and to be true to the principals of the circular economy we should be recycling the bags rather than burning, but surely it’s all about resource efficiency and if using a small amount of plastic can bring about a significant increase in food waste recycling, that’s got to be good. Recovering the calorific value afterwards, through EFW means we get more out of a relatively small percentage of the waste. We did some work on the amount of plastic used for waste and recycling bags, including food waste liners, we calculated that, in recycling schemes, 300 tonnes of resources are recovered for every 1 tonne of plastic bags, that looks like resource efficiency to me.

Posted by James Lee on July 2, 2018

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