Biowaste Collection in Sweden

A new report by the Swedish Excellence Center Waste Refinery prepared for the Swedish government recently analysed biowaste collection in Sweden and different options for increasing its efficiency. An interview with Linda Zellner of the Swedish chemical company Perstorp about the potential contribution of compostable plastics.

Ms Zellner, could you give a short overview of Swedish waste management and the status on a separate biowaste collection?

The main target for waste management here in Sweden is to reduce and/or reuse as much as possible. We should strive to minimise the amount of waste through improved production methods and consumption behaviours. In the biowaste system, waste can enter two different biological treatment streams: composting or anaerobic treatment. The biowaste collection is increasing year by year, and now 15 per cent of the waste enters this collection stream. Around 33 per cent of the waste goes into different types of recycling streams such as metals, paper and plastic. The main waste stream goes into energy production where about 52 per cent of the waste ends up.

How have Swedish consumers reacted to biowaste bags made of compostable plastics?

For many people plastic is related to a waste problem to begin with. So using a plastic material that is compostable can be a bit confusing. Spreading information about the material, composition and the environmental impact is very important. Once they used the bag, became familiar with it and compared it with other solutions, they preferred the compostable plastic version which was sealable and reduced smell and flies. It did not leak and it was easy to handle. The new solution was also better from a waste collection point of view since the bags remained closed unlike the other options such as paper bags. Bins and larger collection vessels did not get dirty, and costs could be cut as cleaning is not necessary.

From a processing perspective, how did the compostable plastic bags perform in the tests? What are the challenges and opportunities?

Biological waste treatment systems in Sweden are not really prepared for this type of solution yet, which is obvious from the assessment carried out by Waste Refinery. When the plastic bags entered the biowaste treatment stations, they faced some challenges in the pre-treatment phase where they got caught in the shredding machines, but the analysis showed that the limits for the SPCR120*) were mostly achieved. Different bag options – compostable and paper bags – are having a comparable environmental impact at the moment from a lifecycle perspective. However, as the compostable bags could help to potentially increase food waste collection due to high consumer acceptance, better hygiene and cost-cutting effects, treatment processes need to be adapted.

What are the next steps you would recommend to the Swedish authorities and waste managers?

We need to continue to develop more sustainable solutions but also adapt our systems so that these solutions can be implemented. This means upgrading the waste treatment facilities to avoid the bags from getting caught in the shredding phase and on the screws used in biogas facilities and composting units, since we have these two possibilities in Sweden.

Considering the material composition of the compostable plastic bag, there is still some discussion about them being only “partly” biobased. This – just as the adaption of facilities – is “work in progress”. Functionality of product and material choice and composition always go together. Using the least amount of the most efficient material with as much renewable content as possible should be the target. Even if compostable biowaste plastic bags are not yet 100 per cent biobased, they are considerably thinner than paper bags. Also we just need one bag to enable a hygienic biowaste collection. Addressing the problem of leaking paper bags, the report suggested using two bags. A whole lot of additional material needed.

We need to view the entire picture and not only parts of it to make this work, and also continue to inform and educate both users and converters about the different material.

*) Certification rules for digestate from biowaste by the quality assurance system of Swedish Waste Management.

Source: European Bioplastics e.V.


Linda Zellner – Photo: Perstorp