A Circular Filtration Solution to Eliminate PFAS & Other Micropollutants from Wastewater

The EU-POP Regulation

PFAS-containing products are considered as waste and must be disposed of accordingly. This is typically done via incineration, which, however, is potentially bad for the environment as it doesn’t fully break down toxic compounds. 

On the other hand, when capturing PFAS onto an activated carbon, a solution for PFAS’ complete elimination now exists. DESOTEC has put together a new technique, allowing the complete destruction of PFAS adsorbed on activated carbon. This consists of pyrolysis followed by neutralisation of gases, meaning all PFAS are broken down and fully destroyed.

In particular, this can be achieved if PFAS levels onto the spent carbon do not exceed the thresholds reported in the persistent organic pollutants (POPs) EU Regulation (2019/1021)  (see below):

• PFOS (maximum 50 mg/kg)
• PFOA (maximum 1 mg/kg) 
• PFHxS (maximum 1 mg/kg)

Instead, if the PFAS contamination is above these maximum limits, the activated carbon must be disposed of elsewhere in accordance with local regulations, e.g. by high-temperature incineration. 

The EU Drinking Water Directive

The revised Drinking Water Directive reports emission limits for a series of compounds which may be present in water for human consumption. 

Concerning AOX, the regulation mandates the following thresholds:

• 1,2-dichloroethane: 3 μg/l;
• Trihalomethanes Total (sum of concentrations of chloroform, bromoform, dibromochloromethane and bromodichloromethane): 10 μg/l.

Besides AOX, the above mentioned directive has introduced since January 2026 tighter PFAS emission limits in water:

• 0,50 μg/L for the Total PFAS;
• 0,10 μg/L for the sum of 20 PFAS.

Italy went even beyond that by setting a limit of 0,10 µg/L for the sum of 4 PFAS (PFOA, PFOS, PFNA and PFHxS). 

In addition to this, the upgraded regulation requires EU Member States to monitor PFAS and act immediately when limits are exceeded. For WWTP players, this means relying on treatment solutions that can be implemented quickly and without disrupting daily operations. 

Here are some case studies that prove DESOTEC’s activated carbon-based filtration to be effective in removing PFAS and other micropollutants from water:

A WWTP manager requested DESOTEC to bring down PFAS in their wastewater from 732 µg/l to 100 ng/l (drinking water limit). DESOTEC put in place a 2-filter setup: the first one to remove COD and larger PFAS molecules; the second one to capture smaller PFAS molecules such as perfluorobutanoate (PFBA), perfluorobutanesulfonic acid (PFBS) and trifluoroacetate (TFA). This solution allowed the client to meet the drinking water regulation requirements. Read more here.

A company manages a water purification system on behalf of several chemical firms that shares a site in Belgium. As they release their water in a nearby river, the client must comply with stringent emission limits. In particular, they had to reduce PFAS concentration from 300 to 100 ng/l. Considering activated carbon as a promising solution, the firm approached DESOTEC. We installed four Mobicon filters downstream of their water purification system. Two filters are placed in parallel at the front, and behind each is a second filter. The first filters are meant to adsorb the organic components (TOC) from the wastewater flow. Instead, the second filters are designed to remove PFAS. Thanks to this setup, the customer became fully compliant with the regulation limits. Read more here. 

A chemical producer discovered PFAS (4 mcg per liter, of which 3.6 mcg per liter being PFOS) in groundwater during a piping replacement project. Knowing DESOTEC‘s expertise in dealing with these harmful substances, the company gave us a shout. Taking into account a flow rate of 6.5 m³/ h, we opted for two 2m³ Mobicon 2000 filters in series filled with an activated carbon particularly suited to long-chained PFAS and PFOS. As a result of our intervention, the treated water met PFAS emission limits throughout the duration of the project (3 months). Read more here. 

A pharma company discharges halogenated API residues into its wastewater, thus containing AOX (mostly chloroform, chlorophenols and chlorobenzene). Alongside AOX, their wastewater also contained organic components. To meet legal requirements, the pharma producer had a two-step purification process: a bio-filter to capture organic components, followed by activated carbon to deal with AOX. Yet, the carbon was reaching saturation quickly, and therefore was being exchanged every three weeks. This led to long production downtime and significant waste disposal cost. To sort out the issue, the firm turned to DESOTEC for assistance. After installing a large MOBICON, the company could efficiently remove AOX while exchanging the filter only once a year, hence reducing their purification expenses. 

Following an upgrade of environmental regulations, a WWTP in Portugal was no longer able to ensure compliance with the stricter AOX emission limit (0.4mg/L)​. The plant manager contacted DESOTEC and asked for a rapid solution. As the contaminated flow (9 m3/h) contained suspended solids (80 mg/L), DESOTEC installed 1 MOBICON 2000 as a pre-treatment. Downstream of that, 1 MOBICON packed with ORGANOSOB Plus was dedicated to AOX removal.

A chemical giant had to remove AOX (31,24 mg/L) from the wastewater generated by their pesticides batch production. As wastewater was released into a nearby river, the company was being pressured both by the local community and regulators. Accordingly, the chemical producer reached out to DESOTEC. We enabled the customer to meet legal requirements and avoid complaints by installing 2 MOBICON filters.