We wanted to recycle our plastic waste in the lab but had no idea about its fate.

By Lena König and Thomas Pribasnig

Everybody who has worked in a molecular biology lab knows that the turnover of plastic products is extremely high. In the heat of the moment, we go through dozens of little, pristine plastic tubes that end up in the general waste within hours or even minutes of usage.

Plastics are a valuable resource

In Austria, this general waste gets picked up by the municipal waste collection services and is then incinerated with energy recovery. While burning plastic waste prevents plastic particles from polluting the environment, it generates roughly twice the amount of greenhouse gas emission as recycling. Moreover, incineration irreversibly destroys the precious material of which plastics are made: synthetic hydrocarbons that are predominantly produced from non-renewable resources such as natural gas and oil. This waste-to-energy strategy does not reduce the demand for new plastic products and thus counteracts the goals of a circular economy. On the other hand, substitution and recycling of plastic products can substantially reduce both greenhouse gas emissions and virgin plastic production.

Yes, we can (recycle lab plastics)

In our lab of about 25 people at the University of Vienna, we use approximately 1.3 tons of plastic per year. Some of it will be gradually replaced with alternative materials and reusable products, but a large part will remain to be discarded after a single use. This remaining plastic waste can largely be collected for recycling instead of being disposed of in the general waste, as described here. Recycling sounds soothing, but do we really know what happens after we dutifully dump different plastic types in separate collection containers?

Left: Lab plastic waste is usually directly disposed of in the general waste or first decontaminated, and therefore ends up being incinerated. Here, 15 kg of plastic waste collected over 6 weeks are shown. Right: In our lab, that plastic waste is collected by type (HDPE, PP) after removal of the bulk of liquid waste, then decontaminated if necessary, and finally picked up for recycling.

Recycling via ARA is not transparent enough

One would think that in Austria, tracing the fate of waste would be an easy undertaking, as, after all, we pride ourselves on living in an open, democratic society, and waste management is a necessary but mundane task. Right? Thomas Pribasnig und Max Dreer from Green Labs Austria were surprised to encounter substantial hurdles when they contacted ARA (Altstoff Recycling Austria), the corporation that organizes about 80% of Austria’s waste collection and sorting. As a matter of fact, despite their key role in Austrian waste management, ARA could not provide us with concrete numbers on plastic waste. At the time of our inquiry, we were told that those numbers were simply not centrally available. Data collection was rather the responsibility of the multitude of employed subcontractors, which did not show any interest in answering our questions. For example, we still don’t know exactly how much of the total plastic waste is currently collected, sorted and subsequently recycled.

What we know – low plastic recycling rate in Austria

The good news is that in contrast to other European countries, plastic waste in Austria officially does not end up in landfills. The bad news is that according to Eurostat, out of the 380,208 tons of Austrian plastic waste in 2018 (43 kg per person), only 25.3% or about 11 kg per person were actually recycled while the rest was incinerated. The large bulk of plastic waste is comprised of packaging (302,000 tons or 34 kg per person in 2018). If only plastic packaging waste is considered, the recycling rate increases to 31.9%. But even with this slight increase, Austria’s plastic recycling rate is far below the EU target rates of 50% and 55% for plastic packaging waste by the end of 2025 and 2030, respectively.

The fate of our lab plastic waste

As an organization promoting recycling of lab plastic waste it is imperative to know about its afterlife. Too many unknowns in the waste flow provided by the municipal waste management led us to team up with the local non-profit Stöpselsammeln.at (shout-out to Andrea Tramontano and Nathalia Jandl for facilitating this collaboration). This non-profit picks up plastic waste that is pre-sorted by type (PP, polypropylene and HDPE, high-density polyethylene), ensures mono-material separation and finally sells it to the recycling plant PreZero Polymers in Kärnten, Austria.

Lena and Thomas visiting PreZero Polymers in Haimburg, Kärnten.

At a visit to PreZero Polymers last fall, we learned a lot. As one of the few plastic recycling plants in Austria, it recycles about 80,000 tons of sorted post-consumer plastic waste per year, that is, plastics recovered after household and commercial usage. The plant in Austria buys polypropylene (PP), high-density polyethylene (HDPE), polystyrene (PS) and mixed polyolefins (MPO) waste from Austria and neighboring regions in Germany, Italy and Slovenia, while another plant in northern Italy also accepts low-density polyethylene (LDPE). Bottles made from PET (polyethylene terephthalate) and plastics from electrical waste are recycled by other companies. Importantly, the success of the recycling process highly depends on the quality of sorting and thus also relies on ARA and other sorting operations: only relatively clean plastic that is 80-100% of purely one type can be turned into plastic granulate that matches the quality of the starting material and even virgin plastics. The versatile principle “shit in, shit out” also applies to recycling.

Mechanical plastic recycling – the process

The whole mechanical recycling process at PreZero Polymers involves recovery at various levels. The large bales of pre-sorted and flattened plastic waste that arrive at the plant get first roughly shredded and washed, and the wastewater thereof is transported to a nearby wastewater treatment plant. After another sorting via an optical sorting machine, the plastic parts get separated by density from remaining contamination such as paper, aluminum and other plastics. These contaminants are why 1,000 kg of plastic waste only yields between 650 to 850 kg of ready-to-use granulate. Fortunately, the contaminants do not go completely unused as they provide energy by incineration for a regional cement plant. The plastic parts get further shredded into smaller pieces and finally get melted, mixed with additives and color, formed into granulates of various colors and plastic types, and then sold.

Room for improvement

While we now know that all our collected lab plastic waste goes to Kärnten and gets mechanically recycled, we cannot be sure about the quality of collection and sorting of the municipal plastic waste. Considering the low recycling rate of plastic packaging waste in Austria, we must assume that both collection and sorting of plastics need to be improved. Plastic recycling itself seems to work well, but if the bulk of plastics in Austria never reaches the plant, the opportunity to recycle is missed.

If numbers of PET bottle recycling, the flagship project of Austria’s plastic recycling effort, are any indication for questionable trends, it’s not primarily the collection rate that is at fault. Out of 41,400 tons of consumed PET bottles in 2019 (15% of plastic packaging waste), 78% have been collected in dedicated collection containers, but only two thirds (23,061 tons) of those collected bottles were recycled. Considering that PET bottle recycling is dubbed “easy”, the overall PET bottle recycling rate of 56% still seems too low. A post-collection inefficiency is likely even higher for the rest of plastic packaging waste, and the question remains why the gap between collection and recycling rate isn’t smaller.

The future is circular

While we depend on governmental institutions in many aspects of our lives, we forget that we are free to get active at an individual level and inspire change. A beautiful example for a self-determined initiative is the open-source hardware plastic recycling project Precious Plastic, which provides a global network for an alternative plastic recycling system. Lucky for us, there is a recycling workshop right around the corner from where we are located in Vienna. We are truly excited to experiment with going full circle in the future. Perhaps our precious single-use plastic tubes, bottles and pipette tips will find a second, long-lasting life as exquisite and functional lab objects.