Zürcher KVA: The end for recyclable plastic waste

"We want to promote the material recycling of plastic waste," says Alfred Rudin, managing director of Zürcher Abfallverwertungs AG, or ZAV for short. It includes all five Zurich waste incineration plants (KVA) in Dietikon, Hinwil, Horgen, Winterthur and the city of Zurich. Since January 1, 2021, ZAV has been subject to an acceptance stop - companies are no longer allowed to deliver plastic waste. With this step, the waste incineration operators are doing pioneering work to increase the potential of recyclable plastic waste from commerce, industry and construction. That's a good thing, because recycling plastics is still in its infancy in this country. For Rudin, it's clear: "Such waste fractions, especially if they are unmixed and uncontaminated mono-batches or quantities from collections, don't belong in MSW."

What does the Federal Office for the Environment (Bafu) say about Zurich's approach? There is nothing to be said against such a collection stop, according to the Bafu's Waste and Raw Materials Department. However, it must be ensured that the separately collected plastics are actually recycled. "If waste fractions from commerce, industry and construction are collected in mixed form and exported abroad, a permit from the Bafu is required. In addition, it must be proven where and for what purpose the waste is exported," reminds Isabel Junker of Bafu.

Samples are made

The question arises as to how the Zurich MSWI operators control the acceptance stop. According to Rudin, the relevant personnel at the MWIP must pay particular attention to ensuring that no recyclable plastic fractions end up in thermal disposal. On average, around 3,000 tons of combustible waste are delivered to Zurich's five MSWIs every day. Rudin speaks of around 1,000 routine spot checks that are necessary to control these tonnages. 

Is the MWIP fuel missing?

Zurich's MSWIs not only incinerate their waste, they also supply a lot of energy in the form of electricity and district heating. Plastic waste is known to be a good fuel. With the elimination of the fraction, the MSWIs lose between 10,000 and 15,000 tons of combustible material per year, estimates the ZAV managing director.

What does that mean for the district heating supply, especially in the heating season? Rudin waves it off, because he has made provisions and secured "fuel" to the tune of over 6,000 tons per year. The MWIP operators fall back on "antique refuse". This comes from the dismantling of the Tambrig household waste landfill in Obfelden, Canton Zurich.  

Is there a market for material recycling?

Closing material cycles is the order of the day. But is there a market for recyclable plastic waste? According to the ZAV managing director, up to 100 francs per ton are paid for sorted and good quality. The price is different for mixed fractions, which first have to go through a sorting plant, which is not free of charge. It should be noted that disposal in the waste incineration plant also has its price - around 150 francs are paid for one ton. 

Dormant potential

Around one million tons of plastics are consumed in Switzerland every year. Around a quarter of this is used for durable products such as window frames. Based on figures from Bafu, around 780,000 tons of plastic waste are produced each year, of which around 650,000 tons are used for energy in waste incineration plants and a good six percent in cement plants. In total, more than 80 percent is disposed of thermally.

Focus on trade and industry

The largest quantities of plastic waste in Switzerland come from trade and industry. This is why Zürcher Abfallverwertungs AG wants to apply the leverage here with its acceptance stop: More material plastic recycling is very effective in these sectors and brings large savings in primary resources with justifiable effort. Sorting out in so-called bulky building materials sorting plants is also expressly desirable. In order for a recycling economy for recyclable plastics to function, sufficiently large quantities are needed, says Rudin.

According to him, ZAV wants to strengthen the partnership with recycling companies in the future: The MSWIs would buy sorting residues that cannot be recycled from such companies in order to dispose of the latter thermally.