The introduction of bioplastics to South Africa’s burgeoning and well- developed recycling industry should carefully be considered, says plastics industry association Plastics SA.

Bioplastics are plastic materials produced from renewable biomass sources that are not grown or intended for human consumption, such as vegetable fats and oils, corn starch, straw, woodchips, sawdust and recycled food waste. There are two types; biodegradable bioplastics and nonbiodegradable bioplastics, where the original building blocks of conventional polymers are not sourced from petrochemicals.

Although the association agrees that bioplastics could be ideally suited to certain applications, it is important to realise that, if not properly sorted from the solid waste stream, they could potentially have disastrous and costly consequences on the plastics recycling industry which has become an integral part of South Africa’s economy, explains Plastics SA executive director Anton Hanekom.

He points out that there is uncertainty about the impact that these materials will have on the efficient operation of existing recycling operations and the integrity of recycled products, should biodegradable/compostable products be incorporated into recyclate.

During 2018 alone, about 519 370 t of plastic waste was collected for recycling and provided employment to about 60 000 people. This meant that about R2.3-billion was injected into the informal sector during the year through the buying of recyclable-plastic waste,which, in turn, was used to make many new plastic products where medium- to long-term durability is a key requirement, such as water pipes, builder’s film, fencing and decking, as well as carpeting, geotextiles, strapping and plastic timber.

If there were a separate recycling stream for a certain plastic type, the bioplastic material could simply be recycled together with its conventional counterpart, for example, bio- polyethylene terephthalate (PET) bottles could be recycled with PET bottles. These materials are identical to the petrochemically sourced materials and are not compostable.

Hanekom says bioplastics offer various benefits, such as saving fossil resources by using waste biomass (not crops for food), which regenerates and provides the unique potential of carbon neutrality.

However, it is important to recognise that manufacturing bioplastics is a complicated and energy-intensive process that still depends on fossil fuels, which are also used in the manufacturing of fertilisers and pesticides, he adds.

“Biodegradable and compostable materials are often regarded as a possible solution to littering, as it can be decomposed by micro- organisms without producing harmful residue during decomposition. However, the processes of biodegradation and decomposition depend on very specific environmental conditions and certain factors need to be considered.”

Product Specifications

Firstly, products with any of the compostability standard specifications ASTM D6400, ASTM D6868, EN 13432 or ISO17088, are certified for very specific composting conditions only to be found in industrial composting facilities.

Such materials have been tested and certified to degrade under specific conditions at about 60 ºC – the specifications do not cover home composting, landfills or environmental degradation at ambient temperature, adds Hanekom.

Further, the degradation rate of these materials has been shown to be significantly slower in an aquatic environment than in soil.

Secondly, South Africa currently has very few large-scale industrial composting facilities that are maintained to the conditions required by the abovementioned certifications.

Thirdly, there are currently no large-scale post-consumer waste management programmes for the separation and processing of biodegradable and compostable packaging. Consequently, these materials have no intrinsic value to formal or informal waste collectors, so the products are likely to remain in the environment or at best, end up at landfill.

Although bioplastics can be recycled, it would require a separate stream for the recycling of post-consumer biodegradable or compostable plastics materials parallel to the current one. Hanekom stresses that it is important to consider the entire economic value chain, such as the input and processing costs associated with getting access to post-consumer bioplastics. The initial low volumes of these materials would make dedicated collection schemes very costly and make the economic model for composting facilities less financially viable. Moreover, because they look so similar at face value, it is quite possible for incompatible, traditional plastics to accidentally end up in the composting facility – thereby contaminating the composting facility.

He points that the South African Initiative to End Plastic Waste has formed a working group that assesses biodegradables and compostables. To this end, a position paper on biodegradable and compostable packaging materials is being developed in partnership with sustainable strategists The Moss Group. It is expected that this paper will be completed next month and that key elements of this paper will be considered when developing a strategy for dealing with these materials in the near future.

“Plastics SA feels that it is important to stress that the introduction of biodegradable and compostable material remains a major concern for the plastics recycling industry, as the required infrastructure to separately collect and process these materials does not exist in South Africa.”

Hanekom concludes that these alternatives to conventional plastic packaging do not change consumer behaviour with regard to littering.

”As a result, one problem could potentially be replaced with another, as these materials inadvertently end up contaminating the recycling stream.”