Claims about the recyclability of biodegradable bags and calls for their exclusion from a proposed levy on carrier bags have sparked a heated debate in the plastics industry.
Quantities of degradable plastic films as low as 2% could cause “significant, detrimental impacts” to the quality of plastics recyclates, a study commissioned by European Plastics Converters (EuPC) indicated. EuPC said the separate collection of degradable plastic products was needed.
The British Plastics Federation’s Recycling Group (BPFRG) also claimed that no biodegradable plastics could not be recycled with conventional plastics “without catastrophic effects”.
But the Oxo-biodegradable Plastics Association (OPA) said such claims were confusing as they did not discriminate between different types of biodegradable bags (see box below).
EuPC’s study confirmed OPA’s view that bio-based bags, such as the hydro-degradable ones used for food waste collection in the UK, were not recyclable with ordinary plastics bags, Michael Stephen, OPA chairman, told MRW.
But he maintained that oxo-biodegradable bags, which are similar to ordinary plastics bags but contain a small quantity of additive that accelerates their degradation, could be recycled with ordinary plastics without any significant detriment to the recycled product.
Stephen said a 2012 study by the South African research centre Roediger Agencies supported the claim (see attached document, right).
“Two per cent of oxo-bioplastic contains only 0.002% of prodegradant additive, which is too small to have any effect at all,” he added.
Biodegradable plastics bags come under the inquiry by the UK parliament into the introduction of a 5p carrier bag levy in England in 2015
The Government has suggested that biodegradable plastic bags could be exempt from the tax, alongside paper bags.
The Packaging and Films Association voiced their concerns over the possible exclusions, saying that it would encourage the use of materials that were made to be thrown away.
The BPFRG is also against the exclusion of biodegradable bags, pointing out they were included in the current taxation system in Northern Ireland and Wales.
Stephen said that oxo-biodegradable bags should be exempt from the levy as they were designed to dissolve in the environment, while bio-based ones should be included as they contributed to litter unless they were collected and processed in anaerobic digestion facilities.
“The inquiry is a good opportunity for the public and decision-makers to begin to understand oxo-biodegradable technology and to stop confusing it with hydro-biodegradable technology,” he told MRW.
The recent concern over biodegradable plastics follows debate in 2011 after Defra published a report from Loughborough University questioning the environmental impact of oxo-biodegradable bags. Supermarket giant Tesco stopped using the bags on the back of the government-commissioned study.
Main types of biodegradable plastics:
Oxo-biodegradable plastics are made of petroleum-based polymers such as polyethylene and contain additives, usually metal salts, which accelerate their degradation when exposed to heat and or light. Their life-span depends on the quantity of additive.
Oxo-biodegradable bags are used only by a small number of retailers in the UK, according to OPA.
Hydro-biodegradable plastics are usually made from vegetable products such as starch. In the UK, they are used mainly as food waste containers. They degrade only in a high-microbial environment.