A “first-of-its-kind consumer behaviour trial” which involved households receiving groceries in packaging clearly labelled as compostable has reported a fivefold increase in consumers disposing of it in food waste bins.

The experiment – led by Ocado, Recoup and Compostable Coalition UK – saw 120 households in Medway, Kent receive grocery boxes with goods in both compostable and plastic packaging.

The participants were informed they could dispose of compostable packaging in their food and garden waste bin, and any compostable packaging was marked with newly developed labels by environmental charity Hubbub, with input from the not for profit on-pack recycling label scheme OPRL. Households also received educational resources designed by Hubbub, with insight from behavioural scientists at the University of Sheffield, which encouraged residents to check packaging labels, use their food waste bin, and explained the composting process.

As well as the increase in consumers disposing of the compostable packaging in food waste bins, the trial saw the amount of food discarded in food waste bins increase by 23%, while contamination levels in food and garden waste bins dropped on average from 9% to just 3% by the end of the trial.

“Compostable packaging offers a new way to achieve circularity for some of the most challenging hard-to-recycle plastics,” said Julia Schifter, VP strategy analysis of packaging supplier TIPA and co-founder of Compostable Coalition UK. “Yet, the proper collection and treatment of compostables is key to achieve a full circularity for these products. The results of our study clearly prove that once consumers are provided with a label that positively instructs them where to discard such packages, their ability to behave accordingly increased dramatically.

“Moreover, it also increased their overall disposal of food waste in the food waste bin while significantly reducing contamination,” she added.

Items involved in the trial included confectionery, snack food, fresh produce, teabags, coffee pods, and shopping bags from retailers and brands including Co-op, Ocado, Lipton Teas and Infusions.

The Compostable Coalition UK advocates for greater use of compostable packaging and has targeted three types of widely used plastic packaging which are all considered ‘hard to recycle’ and have negligible or no recycling venues in the UK or worldwide; namely consumer flexible packaging (such as crisp bags and fresh produce bags), small format (such as coffee pods and teabags), and single-use serviceware. It also seeks to demonstrate the “practicality of effectively collecting, sorting and recycling compostable packaging via existing UK infrastructure”.

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Source: Compostable Coalition UK

The disposal of compostable packaging in the food and garden waste bin is not currently mandatory nationally, and advice varies between local authorities. Whilst compostable packaging is designed to be collected and treated along with food and other bio-waste in industrial composters, only 51% of councils in the UK offer food waste collections, and 17% offer a co-mingled food and garden waste collection. However, many do not include compostable packaging as a target material due to contamination and processing concerns.

“This trial reinforces the message that providing consumers with clear, visible labels can have a positive impact on both participation and contamination. The findings of the pilot back up OPRL’s own consumer research, which shows that consumers look for information on recycling at the point of disposal,” said Alice Harlock, director of technical and member services at OPRL.

“In our survey, the majority – 54% – also reported the greatest barrier to recycling was confusion over whether items were recyclable. So we can be confident that tackling confusion with clear labels and instructions will help to drive greater volumes of material for recycling,” she added.

The trial’s findings will be used to inform Defra’s new Simpler Recycling reforms, which mandates the collection of food waste from all households across England by 2026.

“We were delighted to participate in this trial which has delivered such positive results. Ocado remains committed to continued collaboration with the industry to determine the role compostable packaging can play in the circular economy, especially when supported by an effective collection, sorting and recycling infrastructure,” said Laura Fernandez, senior packaging and sustainability manager at Ocado Retail.

Alongside the Medway experiment, Compostable Coalition UK also undertook a composting trial at Envar, one of the largest composting sites in the UK.

The work saw 13 tonnes of compostable items including coffee pods, teabags, fresh produce packaging, twist wraps, snack food packaging and single use serviceware tested for their effectiveness to biodegrade under the normal operating conditions of an industrial composting site. Results showed those products supplied in their ready-to-use state biodegraded successfully, with the finished compost passing PAS100 certification, the high-quality standard for compost in the UK.