Used PVC products are too good to throw away. The European PVC industry has organised a recovery system for the most important PVC products in order to save valuable resources and has set ambitious goals for the future.
Increase in Recovery Quotas
The AGPU and other associations have commissioned the Conversio Market & Strategy GmbH at regular intervals to compile data about PVC waste in Germany. In 2017, the amount of PVC waste was approximately 695,000 tonnes (647,300 tonnes in 2013). This corresponds to 1-2% of the overall volume of household waste and industrial waste similar to household waste. The share of post-consumer waste from this amount was at 568,100 tonnes (520,300 tonnes in 2013). Approximately 155,000 tonnes (140,000 tonnes in 2013) of this amount were recycled mechanically and by feedstock recycling. If production waste (post-industrial) is included in these statistics, the amount of recycled materials totals approximately 257,000 tonnes (243,000 tonnes in 2013). In actuality, the recycled amount is even higher. “In-house recycling” is not included in these statistics. During this process, the production waste generated in converting machines is comminuted and then immediately recovered.
Based on the overall amount of waste (post-consumer and post-industrial), the recycling quota is approximately 37%. Additional PVC waste undergoes energy recovery through state-of-the-art, cutting-edge technology – primarily in waste incineration plants. Since PVC has a calorific value similar to that of brown coal (approximately 19 MJ/kg), the material contributes positively to energy balance when incinerated in household waste (approximately 11 MJ/kg).
Mechanical recycling has been used in PVC production and processing for many decades. The largest part of unmixed waste flows directly back into production. Since the beginning of the 1990s, the PVC industry has developed a number of initiatives for the recovery of post-consumer waste which are now established on the market.
PVC construction materials make up the largest amounts in waste management. The Arbeitsgemeinschaft PVC-Bodenbelag Recycling (AgPR) and RoofCollect – the successor organisation of the Arbeitsgemeinschaft für PVC-Dachbahnen Recycling (AfDR) – handles this waste in Germany. Rewindo Fenster-Recycling-Service GmbH has established a broadbased, take-back system for windows in Germany in close cooperation with their recycling partners. PVC-coated tarpaulins are recycled through the EPCOAT initiative. Since the beginning of 2005, Rohr-Recycling in Westeregeln – a subsidiary of the Tönsmeier-Gruppe –and Kunststoffrohrverband (KRV) have established an alliance to increase the amount of materials to be recovered. This initiative takes back PVC pipes throughout Germany and arranges for the recycling of used products. Furthermore, the PVC industry in Germany cooperates with the European initiative Recovinyl established by VinylPlus (former Vinyl 2010).
In Austria, the industry initiatives ÖAKF for plastic windows (Österreichischer Arbeitskreis Kunststoff-Fenster)and ÖAKR for plastic pipes (Österreichischer Arbeitskreis Kunststoff-Rohre) organise the return and recycling of used PVC materials. The amounts collected in this manner are processed primarily by Reststofftechnik GmbH in Salzburg. Furthermore, the dissolving process VINYLOOP® developed by Solvay allows the recycling of previously difficult-to-treat composite materials (such as PVC/copper made from cable scraps or PVC/polyester from used tarpaulins). Innovative VINYLOOP® technology was launched after completion of a ten-kiloton plant in the Italian city of Ferrara at the beginning of 2002.
Recycling possibilities are also available for packaging, cables, credit cards, and mixed PVC waste. These offers and numerous recycling products are listed in the PVC-Recycling-Finder of the AGPU. The PVC industry has contributed greatly towards a sustainable and resource efficient economy with its forward-thinking, takeback and recovery systems for used products.
Hydrogen chloride in pure form is obtained by thermally treating PVC products. The hydrocarbon part in PVC is used to generate heat and electricity in the same process. Hydrogen chloride then goes back into PVC production. Feedstock recycling can be divided into processes with and without the limitation of chlorine. The recovery process without the limitation of chlorine is especially suitable for contaminated and PVC-rich mixed plastic material fractions. The PVC industry has been researching suitable forms of technology for the feedstock recycling of PVC-rich waste streams since 1992.
The rotary kiln at the recovery plant at DOW/BSL in Schkopau is technologically suitable for PVC-rich waste streams in feedstock processes. PVC waste in solid and liquid form can be recovered at this plant, which started operations at the end of 1999. Through the thermal treatment of waste, the hydrogen
chloride is separated and also the released energy is used. Processed into hydrochloric acid at the plant, it can be used again as a raw material for the production of PVC.
In the production of calcium carbide at Alzchem Trostberg GmbH in Hart, high calorific plastic fractions with a chlorine content of up to 10% can be used. These waste materials are used to increase the amount and calorific value of the resulting carbide furnace gas. Ecoloop, a subsidiary of Fels-Werke GmbH, employs a new technology for the energy-efficient conversion of organic and carbon-rich materials such as used wood or plastic into purified syngas as an energy source. In the process, raw materials with a chlorine content of up to 10% can be used.
Currently in Germany there are about 73 plants for the thermal treatment of mixed municipal waste. They have an approved total capacity of approximately 18 million tonnes at their disposal.
In the past, it was assumed that PVC contributed approximately 50% towards the chlorine input in waste incineration plants. Today, this amount is estimated at about one-third (30–35%). This reduction can be traced back to the recovery activities in the packaging sector, among other things.
The chlorine content in PVC is converted completely to HCl during incineration and removed from the flue gas far below the legally permitted emission limits as defined by prescribed flue gas cleaning. The scrubber liquid is neutralised primarily with burnt lime. The resulting calcium chloride is deposited.
Some waste incineration plants do not work with limestone scrubbers. They neutralise with sodium hydroxide. This results in a valuable brine. In order to reduce the chlorine input, hydrogen chloride can be separated from the flue gas as hydrochloric acid and used again in chemical production. Five waste treatment facilities in Germany – e.g. in Hamburg, Böblingen, Kiel, and in Kempten – work according to this principle.
Another possibility is offered by the SOLVAir® (former NEUTREC®) process from SOLVAY. Sodium chloride is recovered and purified with the help of sodium bicarbonate in the flue gas purification of incineration plants. Facilities used for the treatment of reaction products containing sodium are in operation in Italy and France.
The HALOSEP® process also offers the possibility of recovering chlorine from waste incineration in the form of salt. Waste from the flue gas purification of two major Danish waste incineration plants was treated as part of a pilot program. In doing so, more than 99% of the chlorine was recovered.
Dioxins and furans (PCDD/F) result from almost every incineration process involving organic materials. The amount of these undesired compounds depends heavily on the construction and operation of the waste incineration plants. Remaining emissions are minimized through steps towards flue gas purification (adsorption filter). Since 2000, all European waste incineration plants must emit less than 0.1 ng TEQ dioxin per m3 of exhaust gas, based on EU Directive 2000/76/EG.
Numerous investigations show that the PVC portion of household waste does not effect the amount of dioxin formation and thereby dioxin emissions. The complete sorting of PVC products from waste does not alter the dioxin concentration in exhaust gas. The reason is the salt content which is always present in waste, for which residues of food among other things are responsible. No matter whether with or without PVC: there is no change in compliance with the threshold value of 0.1 ng/m3. Thermal and other control parameters in incineration have the greatest influence on dioxin emissions. It would be better to discuss exhaust gas rather than dioxins. Its toxicity is much higher due to other pollutants. This is the case with the carcinogenic substances PAHs (polycyclic aromatic hydrocarbons such as benzo[a]pyrene) or fine dust particles. A holistic approach to adverse effects is especially important for uncontrolled thermal processes as seen in the following section.
PVC and RDF
The PVC industry arranges for a substantial portion of used PVC to be recovered through various recycling initiatives (among others to be found in the PVC-Recycling-Finder of the AGPU)before the waste reaches refusederived fuel (RDF) processing. In this manner, the chlorine content of the fractions is reduced considerably for RDF processing. The PVC share of “PVC-rich” fractions, which is sorted out during RDF manufacturing, is usually only 5-15%.
PVC products stored in landfills are not posing a risk to human health and the environment. Heavy metal stabilisers may in fact reach the leakage water of landfills in small amounts, but are more or less insignificant in comparison to heavy metals from other sources in municipal waste. It is similar with plasticisers which can migrate from soft PVC through micro-organisms. They are broken down and do not lead to a toxically relevant deterioration of the leakage water. This conclusion was reached by an extensive international research project on the long-term behaviour of PVC products in landfills and under ground. It was conducted by the Technical University Hamburg-Harburg, the University of Linköping, and Chalmers University in Göteborg from 1996-2000.
In principle, valuable materials such as plastics do not belong in landfills. The depositing of untreated plastics and other organic materials is outdated and is no longer permissible in some European countries. Since January 2000, all organic waste in Switzerland must be thermally treated in waste incineration plants before reaching landfills. In Germany, a corresponding regulation in the form of a ban on depositing organic waste such as wood, paper, and plastics has been in effect since 2005 (source: DepV – Landfill Ordinance, Technical Guidelines – Municipal Waste). In Austria, the topic was dealt with in the same way through the Landfill Ordinance of 2008.