1 August 2018 by Elizabeth Slow

Bridgend conflicted over plastic liners

Bridgend county borough council in South Wales is looking at the potential of using plastic bags for the collection of food waste, despite an aim to be a ‘plastic-free’ borough.

A spokesperson for the council confirmed that the authority is in the early stages of researching and investigating this as a possibility.

Residents in Bridgend recieve a brown caddy for food waste, orange sack for cardboard, white sack for paper, blue sack for plastics and metals and a black box for glass

However, the announcement comes as the council proposes to pursue a “Plastic Free Bridgend” and looks at ways to further reduce the “environmental impacts” of its own activities and the activities of those it can influence.

Plastic bags

Recently, a growing number of councils have been weighing up the case for allowing residents to use plastic bags for the collection of food waste, as a measure to increase recycling.

Last month letsrecycle.com reported that Buckinghamshire’s waste authority was allowing some residents to use plastic bag in their caddies for food waste (see letsrecycle.com story).

This is in spite of growing momentum around reducing single use plastics consumption, along with calls from the industry to improve the quality of collected food waste.


The news follows a joint statement from ADBA – the Anaerobic Digestion Bioresources Association – and the Renewabe Energy Association (REA) earlier this month on the need to keep plastics out of digestates and composts.

The statement from ADBA and REA addresses the use of plastic caddy liners. “Where the food waste is going to AD, having consulted with their recycling plant, local authorities may specify conventional plastics rather than compostable plastic caddy liners.

“Conventional plastic liners are cheaper than compostable liners and all liners, irrespective of what material they are made of, are removed before the food waste is digested if the treatment is ‘wet’ digestion only.”

However, in another breath the organisations emphasised the need to reduce plastics contamination: “The biowaste sector is clear that the best way of producing high-quality digestate and compost is through the provision of feedstock that is plastic-free.”

The plastic bags removed during the anaerobic digestion process are often sent to energy-from-waste (EfW), with landfill being the “less preferred alternative,” they revealed.


Currently, residents in Bridgend are asked to recycle their food waste in a brown food waste caddy using green compostable bags.

A report for a meeting of Bridgend council’s overview and scrutiny committee last month, states that “a move from a degradable sack to a single use plastic sack potentially offers a saving with seemingly minimal environmental impact”.

Food waste from Bridgend is sent to Agrivert’s South Wales AD Facility in Stormy Down, Bridgend

And, highlighting the “complexity” of a move away from single use plastics, the report explains that residual waste is currently collected in single use plastic sacks. “To embrace fully a move away from single use plastics would realistically involve a move to a wheeled bin waste collection system.”

The change to wheeled bins was previously discounted, the report notes, and now would potentially involve an investment of around £1 million.


Bridgend has a 15-year contract with organics recycling firm Agrivert which started last summer (see letsrecycle.com story). As part of the contract, Agrivert will recycle around 18,000 tonnes of food waste from Bridgend and Swansea residents at its Bridgend anaerobic digestion facility.

Agrivert has recently defended the use of plastic bags as caddy liners, which it promoted as a way of increasing the uptake of food waste recycling (see letsrecycle.com story).


There is definitely increased interest in using conventional polythene bags for use as food waste caddy liners, as a lower cost alternative to compostable liners, where the treatment process is anaerobic digestion. As we’ve heard, both types of liners are generally removed at the front end by the depacking equipment, so there is no clear benefit to using compostable liners in the first place, other than household perception, perhaps – could it be compostable liners have a psychological effect to engage the householder and increase participation? That may be true at the outset but there seems to be no marked deterioration in participation rates or volume where authorities have introduced the lower cost liners, and in some cases food waste collection has increased. The conflict arising from the use of single use plastic liners is understandable but there is so much more to be gained in the context of resource efficiency, the amount of plastic used is miniscule compared to the resource recovered in energy, and emissions saved through the AD process and diversion from landfill. Evidence collected within the waste management industry suggests the amount of plastic used for the liners could be as little as 0.3% compared to the resources collected. That might not square perfectly with the principals of the circular economy but it makes a pretty good model for resource efficiency.

Posted by James Lee on August 2, 2018

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