High destruction efficiency of PFAS in rotary kilns, annual pollutant load in discharge water less than 10 grams for PFAS.
Indaver has been providing solutions for hazardous waste for 35 years. We always put safety, people and the environment first in our activities. Also in the processing of PFAS-containing waste, we are committed to the best available techniques and cooperate with scientific research in order to destroy this type of waste and thus keep it out of our society. We always do this in line with the permits and share monitoring results and reports with the relevant agencies and the government in full transparency. The inspection services also regularly carry out their own checks on air emissions and discharge water.
Recently, there has been a lot of progress in the field of PFAS.
Thanks to our robust processing methods and new investments, we continue to succeed in our mission to destroy PFAS in line with the very strict new standards. The rotary kilns destroy PFAS molecules with a high destruction efficiency. This is confirmed by measurements of air emissions. The new stricter permit conditions on the discharge water lead to a maximum pollutant load of 2 kg on an annual basis. For the sum of PFAS the discharge will be less than 10 grams on an annual basis. Indaver is therefore succeeding in its mission to provide a solution for hazardous waste in our society in a sustainable and safe manner.
Indaver shared the results of the VITO report publicly in consultations with stakeholders that are directly involved, via an online webinar.
PFAS is not one substance, but a collective name for compounds containing fluorine. In total, there are currently around 6,000 different variants, such as PFOS and PFOA, for example. They are all compounds or molecules that contain both fluorine and carbon, with or without other atoms added.
PFAS are substances added to everyday products. For example, they ensure that products are waterproof as in waterproof jackets or tents, they make furniture grease- or dust-proof, ensure that our sun cream is water-resistant or our mascara does not run, give our Teflon pan a non-stick coating, etc. PFASs have had many applications since the 1940s: in the textile industry, in water for fire extinguishing, in the galvanising industry, for example chromium plating of taps, in the furniture industry, etc. The substances are therefore widespread in our society. A recent study by VMM (the Flemish Environment Agency) shows that at non-critical sites (i.e. sites where there is no PFAS producer or industry using PFAS) PFAS was also detected in 70% of cases.
Most PFAS molecules degrade very slowly (they are persistent) and they can accumulate in organisms. The degradation time of the molecule and therefore the time it remains in the environment depends on the specific composition. That is why they are also called 'forever chemicals'. Some PFAS molecules, e.g. PFOS or PFOA, have already been the subject of scientific research into their harmful effects on human health. PFOS was added to the Stockholm Convention listing of persistent organic pollutants in May 2009. PFOA did not appear on the list until 2019. But for many other PFAS molecules, further research needs to be done.
Through the POPs Regulation, Europe obliges its Member States to irreversibly destroy waste containing high concentrations of highly persistent organic substances. These include pesticides, herbicides, PCBs but also a number of PFAS compounds. POP stands for persistent organic pollutants.
Substances with many organic compounds (and which are therefore flammable) must be burnt at high temperature. Substances that are not suitable for incineration must be safely disposed of in a licensed landfill. With its processing methods, Indaver complies with the current and future POP regulations that are still being drafted.
For 35 years now, Indaver has been offering a solution for waste flows generated in industry or in wider society, for example in hospitals. In the rotary kilns, many different molecules are broken down or destroyed. Three elements guarantee this decomposition: the high temperature of at least 950°C (and average of 1050°C), combined with a long time in the furnace and good turbulence (the turning of the drum) that ensures that the waste comes into contact with fire from all sides. The installation is also equipped with an extensive flue gas cleaning system. We monitor and control numerous parameters and components and have thus been able to prove for years that the plant destroys hazardous waste. The plant operates according to the guidelines of the BREF, a European reference document that prescribes the Best Available Techniques for combustion plants. This is regularly evaluated by the relevant authorities and inspection services with a view to adding additional conditions in the permit.
However, for PFAS molecules, there is as yet no validated measurement method for any residual molecule at the level of the chimney. Commissioned by the government, VITO, the Flemish Institute for Technological Research, therefore developed a measurement method between October 2021 and the summer of 2022 to sample and analyse the flue gases for PFAS residues. Indaver has cooperated in this research so that VITO could test the method on Indaver's air emissions. The first results were presented in the summer of 2022 and confirm that the rotary kilns are very efficient in destroying PFAS molecules. VITO used a scientific model to convert the measured values into depositions, in other words to simulate how much PFAS residues actually fall back down. The result of this study shows that the values are much lower than the EFSA (European Food Safety Authority) values of the 4 most important PFAS components.
Based on the results of the emission measurement campaign, it can also be calculated that the installation is highly efficient. Hence we are helping to ensure that thousands of kilograms of PFAS molecules are removed from our society for ever.
Indaver guarantees that it can destroy Chemours' PFAS-containing waste in the rotary kilns. The rotary kilns are equipped with extensive flue gas cleaning. The water released from the flue gas purification installation is further treated in the water purification installation. Indaver also complies with the new standards imposed in the discharge permit for Chemours' flows. This is also demonstrated by various studies by the University of Utrecht, Wageningen University, Deltares and RIVM which show that the substance used by Chemours (HFPO-DA), whose production waste is incinerated by Indaver in its rotary kilns, is not measurable in the Westerschelde, or only in very low quantities.
PFAS is a collective name for molecules containing fluorine and carbon atoms, with or without an additional atom. The number of carbon atoms determines the length of the chain. The family of PFAS has almost 6,000 variants. Ultra-short chains are PFAS molecules with 2 or 3 carbon atoms. Scientific research shows that the temperature required to destroy PFAS molecules is between 600 and 930°C (Per- and polyfluorinated substances in waste incineration flue gases, RIVM report 2021-0143, J. Bakker, B. Blokker, M. Broekman). Indaver applies a combustion temperature of 1050 to 1100°C.
Indaver also provides the solution for PFAS-containing waste for which incineration is not the most appropriate solution. This waste is deposited in a licensed landfill site.
Thanks to progressive insight and new knowledge about the behaviour of the different PFAS molecules, the processing method for non-combustible PFAS-containing waste has also been adjusted. Indaver now stores the waste in separate salt cells at the landfill site. A salt cell is a zone in which waste is encapsulated so that no water can seep through. The landfill itself also has several impermeable layers. This ensures many layers of protection. The water that is released during the process is burned in the rotary kilns.
Indaver received a discharge permit with very strict conditions in June 2022. This permit remained valid for one year. The procedure for updating the discharge permit is currently ongoing.
Pending these updated discharge standards, Indaver must comply with the reporting limits set out in the Compendium for the Sampling, Measurement and Analysis of Water (WAC), and more specifically for the determination of PFAS in water. These standards are stricter than the discharge standards previously held by Indaver. The discharged wastewater is continuously monitored. The analysis results are reported periodically.
Indaver thus complies with the legislation and (temporarily) respects the stricter discharge standards laid down for discharging PFAS in Vlarem II and the WAC.
The rotary kilns are equipped with an extensive flue gas cleaning system. Wastewater is released during the washing of flue gases. This is further treated in the water treatment plant together with the rest of the site's wastewater.
The water purification system has been expanded in recent months with additional activated carbon filters. In total, there are now 8 activated carbon filters in two connected series of four that are replaced very regularly. After all, we are doing everything possible to meet the new strict standards in the discharge permit. Recent analytical results confirm the good functioning of the set-up, especially for all PFOS and the PFAS listed in the POPs Regulation.
We are also looking forward to a new study by VITO, which is currently investigating the Best Available Technique for capturing PFAS in complex wastewaters. We are doing everything we can to meet the strict standards, but we do note that additional research is still needed to consistently ensure good performance, especially for some specific PFAS molecules.
Indaver itself also aims to continuously improve its processes. At Indaver, too, concern for people and the environment is central. Due to the wide distribution of PFAS in society, there is a need for an installation such as this one of Indaver’s that can destroy this pollution now and in the future. We invest in new technology as soon as it becomes available and also participate in scientific research ourselves. The rotary kiln technology is an efficient technology for destroying PFAS molecules. The results are also promising in terms of impact on water. The measurement results of the past months show a significant reduction of PFAS in the discharge water.