The flame retardant HBCD, used in foam insulation boards for decades, is now considered a contaminant. This means that millions of tons of PS foam waste can no longer be regularly recycled. A best practice for the handling of this waste is needed. With the innovative recycling process used by PolyStyreneLoop (PSLoop), an industry-scale recycling process for HBCD containing PS foam will be developed. This technology has been accepted by the UNEP Basel Convention as a best available recycling technology to handle HBCD waste.
PolyStyreneLoop is a solution with a physical recycling process, based on the CreaSolv® Technology, combined with the destruction of the HBCD. Plastic wastes are selectively dissolved using a specific proprietary solvent formulation. This dissolution is a physical separation process. It is a pre-treatment technology, which has the potential to recover polystyrene and separate them from legislated additives (like HBCD). The process consists of three steps. Steps 1 and 2 are pre-treatment for step 3.
- First, the PS foam waste is dissolved in tanks containing a PS-specific liquid. The solid impurities (adhesives, dirt, cement and the like) are separated through filtration and then incinerated.
- Next, another liquid is added, which transforms the PS into a gel, while the additive (HBCD) stays in the remaining liquid. The PS gel is then separated from the process liquids. Once cleaned, this gel is transferred via a devolatiser and extruder into granulated polymer polystyrene and the liquid, together with the additive, is distilled and re-used in a closed loop; the additives including HBCD, remain as sludge.
- This process is followed by the destruction of the HBCD additive within the sludge in a high temperature waste incineration at 1100 C˚. During the last step, the elemental bromine, used for modern flame retardants, is recovered and can be reused to produce new products, thus closing the bromine loop.
The applied technology turns PS foam waste into new high quality raw material. During the recycling process, all impurities, such as cement or other construction residues, as well as the flame retardant HBCD are safely removed and destroyed, while the valuable bromine component is recovered.
“Demolition waste EPS/XPS is either land filled or incinerated today. It runs perfect and is sufficient.”
Incineration, even with energy recovery, is regarded ever more often as the “resource graveyard”; it is not the answer to the long term circular economy challenge society faces. Land filling of plastics will be forbidden in Europe soon. The pressure on the plastics industry to change course is increasing rapidly. Regulation will soon ban landfill and the European Commission’s Plastic Strategy will very likely include binding recycling targets for plastic waste and for recycled content. Therefore, as EPS industry we need to come up with new solutions. Mechanical recycling (sorting and remelting) can only be an option in a limited number of cases for clean PS foam and HBCD concentrations below 100 ppm.
Mechanical recycling of demolition and packaging EPS/XPS waste is frustrated by quality issues: contamination by dirt, adhesives or legacy additives (HBCD), smell (fish box), limitations caused by colour, density, fire properties and lambda value. The rapid change to grey material will further limit such possibilities. In Europe a substantial amount of collected waste is compacted and send to Asia. India and China already closed their borders in 2018 for this kind of shipments, so export of our waste to Asia cannot be seen as the long term sustainable solution.
The definition of an"EPR scheme" is being discussed at EU and national level. The opinions and meanings vary considerably. The idea of PolyStyreneLoop is that we take a certain responsibility for the End of Life stage of our products. This means we take responsibility to change EPS into a Circular Economy industry. We are convinced and committed to make this change and we can only do this together with all links in the EPS supply chain: raw material producers, flame retardant producers, converters, waste collection and waste testament, all must participate- that is the strength of this initiative! So in that sense all players in the EPS value chain benefit, because it enables them all to continue and strengthen their EPS business. In a number of countries, mainly for EPS packaging applications there are EPR schemes in place and functioning. In those cases we need to build up our position around this and reach out to all involved to fit in PolySyreneLoop in the best possible way, inside such systems or separated outside these systems.
PolyStyreneLoop applies newly developed techniques (Creacycle) and a propriety solvent (CreaSolve).
The combination leads to a clean, technically high quality PS recyclate that can be applied as raw material for EPS production. Contrary to alternatives tested in the past, the solvent is non-flammable and non-carcinogenic. So from environmental, health and safety, as well as technical point of view, the PolyStyreneLoop process is superior to alternatives tested in the past. Alternatives include processes such as Polystyvert and the Sony process based upon limonene. These processes have not proven to separate HBCD from PS below levels of 100 ppm of HBCD in the recycled PS.
In the EU, EPS containing HBCD is not classified as hazardous waste. Typically EPS with HBCD as flame retardant contains HBCD in concentrations between 5,000 and 10,000 ppm. According to EU regulation 1357/2014 material containing less than 30,000 ppm (3%) of HBCD is not classified as hazardous waste.
Membership, roles and representatives
The PolyStyreneLoop Cooperative is an organisation under Dutch law. Members of the Cooperative are industry representatives from the whole polystyrene foam value chain: styrene producers, EPS raw material producers, flame retardant producers, styrene and polystyrene producers, EPS foam converters, XPS producers, waste handling companies, recyclers and national and European associations.
The purpose of the initiative is to change the course of the EPS/XPS industry, to improve the environmental performance and the sustainability image of EPS and XPS. Associations play an important role in defining internal industry policies, estimating the quantity and the geographic distribution of the waste across the country, organising the collaboration of the EPS supply chain and reaching out to regulators to influence the EU and national level regulatory framework. E.g. it makes a big difference whether or not a landfill ban is being enforced. It also is important that recycling targets are binding and that by subsidies and penalties the regulator is steering tin the right direction. Administrative obligations regarding fulfilment of plastic strategy targets and fulfilment of the EPS industry pledge will also be an important task.
It is certainly expected that the project should improve the image of EPS; the PS loop Cooperative is asking companies from across the whole value chain (FR manufacturers, raw material producers, converters, waste collectors and recyclers) to participate. The hard work, the foot work needs to be done by the companies. Practical and financial participation will be a condition to bear the PolyStyreneLoop logo. The financial aspects of the activities need to be agreed upon within the Cooperative. The circle only remains closed as there is a sustainable, economic future for all links, for all companies in the chain one missing link would break up the circular economy model.
We already can see positive publications related to PolyStyreneLoop and hope this will continue and grow. It is certainly expected that the project will contribute positively to the image of EPS in general. Therefore associations are invited to participate. The positive PR will be connected most clearly to participating companies bearing the PolyStyreneLoop logo. Therefore the PS loop Cooperative invites companies from across the whole value chain (FR manufacturers, raw material producers, converters, waste collectors and recyclers) to participate. Use of the registered brand and logo will be allowed only to participating companies, including participating EPS converters. These companies can grab the potentially a massive amount of positive PR. Only the financial value of this (free) positive PR would justify participation.
Logistics and Application
This initiative is about demonstrating the viability of recycling construction waste containing the pop HBCDD, destroying the HBCD while recovering the bromine, and recycling the polystyrene back into insulation. Thereby demonstrating a real commitment to the circular economy. When successful, a roll out to different locations in Europe is foreseen.
Theoretically, the recycling initiative is open to all PS foam waste streams. The process offers opportunities for recycling of EPS packaging. Due to the fact that HBCD was generally not added in this application except for packaging for electrical and electronic equipment, the amount of packaging material containing HBCD is low and will decrease further. From economic and environmental point of view, clean EPS packaging waste with a the HBCD content below 100 ppm is preferably recycled by grinding, followed by application in EPS block moulding or by compacting, melting and pelletizing. The PSLoop initiative does not want to compete with existing recycling and take-back-schemes for EPS packaging waste. However, where ever collection and recycling systems for EPS plastic packaging have not been established, the Polystyrene Loop initiative could be a possible recovery route, especially for EPS packaging from households and commercial applications that are susceptible to contamination with HBCD. PolyStyreneLoop also offers a unique upcycling potential in case of other contamination influencing recyclability or recyclate quality, such as organic waste or fish smell. The PolystyreneLoop recycling option, offering an additional high quality, innovative solution, can positively influence EPS packaging image. In the future, collaboration with PS might be an option. Upcycling single use disposables to energy saving insulation by recycling PS coffee cups at schools …?
HBCD was identified as substance of high concern by the EU REACH regulation. It was also listed as a Pollutant by the UNEP Stockholm convention. According to the Basel Conventions General Technical Guidelines, advanced solid waste incinerations, hazardous waste incinerations and cement kiln co-incineration are accepted destruction and irreversible transformation methods for the environmentally sound disposal of wastes with an HBCD content above 100mg/kg or 1000 mg/kg. Besides these destruction methodologies the Basel Convention General Technical Guidelines included in May 2017 the PolyStyreneLoop dissolution process as a valid pre-treatment process for PS foam waste for the separation of Polystyrene and HBCD. HBCD subsequently is destroyed with recovery of bromine in the BRU (Bromine Recovery Unit). As EPS foam containing less than 3000 ppm of HBCD, in Europe it is not classified as hazardous waste, (April 2018) and not treated as hazardous waste in most countries.
The environmental performance for the recovery of EPS waste depends on:
- the specific type of waste stream and level of contamination,
- existing recovery infrastructure and
- technologies in the EU member states
- logistic organisation and
- transport distances.
For instance, in case of reliable clean EPS packaging waste, which does not contain HBCD or suspect in any other way, mechanical recycling remains an excellent recovery option. The EPS waste is crushed and mixed as foam particles to virgin material during block moulding. Alternatively, it could be compacted, melted, followed by extrusion and chopping to General Purpose PolyStyrene (GPPS) pellets. These options for mechanical recycling are already applied and economically viable in many EU member states.. In case of clean and reliable, often industrial waste feedstocks, this often would be the most economic treatment of such waste. Although the environmental impact of applying PolyStyreneLoop is very positive compared to incineration at End Of Life, mechanical recycling is even slightly better. E.g. the LCA analysis regarding impact category according to EUMEPS EPD for EPS 15 kg/m3 grey material shows a value for Global Warming Potential of 72, 44 kg CO2-eq for incineration and a value of 23,86 kg CO2-eq for mechanical recycling, a reduction of 67%. Not fully comparable, however the LCA analysis for End of Life for EPS ETICS shows a reduction of 47% comparing PolyStyreneLoop with Incineration.
In literature and by some first attempts chemical recycling/ back-to-feedstock recycling options are proposed. The aim of those techniques is to breakdown, to depolymerise, the EPS and PS waste. So chemical recycling brakes down the polystyrene polymer to its basic chemical, styrene, which can be used for many chemical processes. This has as a consequence that afterwards, you need to re-do the polymerisation step, eg suspension polymerisation to produce EPS. This results in a drawback compared to PolyStyreneLoop: firstly the costs of again going through the polymerisation step and secondly the related environmental impact. As these developments are in early stages it is not possible to come to definitive conclusions regarding these techniques. It still needs to be proven if the quality of regained styrene would be of sufficiently high quality to be useful for EPS raw material production. In any case it will take some years to achieve practical useable results.
If the environmental profile of PolyStyreneLoop would not have any environmental benefits compared to incineration, it would be better to incinerate with energy recovery rather than take all the efforts of the PolyStyreneLoop process. Therefore, we asked FH Münster and TÜV Rheinland to do full LCA (Life Cycle Analysis). First results of a Life Cycle Analysis (LCA) according to ISO 14040 and 14044 show environmental benefits in all impact categories for the treatment of EPS demolition waste containing HBCD from ETICS applications in comparison to incineration with energy recovery. In the analysis treatment of EPS demolition waste from ETICS by the PolyStyreneLoop process was compared with incineration with energy recovery. The outcome was that the environmental impact of PolyStyreneLoop for all impact categories was roughly halved! This means that we can significantly improve the sustainability profile of EPS by moving from incineration with energy recovery to PolyStyreneLoop. Fur such waste streams PolyStyreneLoop is an environmental beneficial recovery route. Incineration will remain a way of treating EPS waste. In certain cases incineration will continue to play a role, especially when included in small amounts in other combustible fractions, but also in case transport distances make other options economically not viable.
In literature and by some attempts other recycling options are proposed applying different solvents. The main advantages of the CreaSolv®Process and the CreaSolv® Formulations from CreaCycle are:
- The remaining solvents level is reduced to a degree where it does not have a negative impact on the technical properties of the PS-recyclate. The
critical technical properties and quality of the GPPS recyclate makes it applicable for more the difficult application of expandable polystyrene,
thereby PolyStyreneLoop enables to close the EPS loop for the first time!
- The solvent formulation is not flammable and non-carcinogenic which makes a big difference for all production processes
- The Basel Convention General Technical Guidelines included the PolyStyreneLoop dissolution process as a valid pre-treatment process for PS foam waste for the separation of Polystyrene and HBCD in May 2017. HBCD subsequently is destroyed with recovery of bromine in the BRU (Bromine Recovery Unit). This is not the case for alternative processes and therefore these will not be permitted.