PFAS Treatment Tests
Finding the right treatment chain to tackle forever chemicals
Project overview
Client: Anonymous
Industry: Chemistry
Key results
Regulatory compliance
TFA reduced from 8 ppm to below the 1 ppm regulatory threshold using RO membranes.
Technology selection
The most effective and cost-efficient treatment chain identified through on-site testing.
Process insight
Detailed data on membrane performance, resin behaviour, and preconcentration effects.
The challenge
A chemical industry operator needed to prove, through on-site pilot testing, that its wastewater could be treated to meet tightening PFAS regulations before committing to a permanent installation.
PFAS, or per- and polyfluoroalkyl substances, are a family of man-made chemicals that have been used in industrial processes for decades. Their nickname says it all: forever chemicals. They do not break down in the environment, they accumulate in living organisms, and they are increasingly linked to serious health concerns. In recent years, their presence in water bodies across Flanders and France has become a major regulatory and environmental issue.
This client, a chemical industry operator, had been generating wastewater containing trifluoroacetic acid (TFA), a specific PFAS compound, at concentrations of around 8 Parts Per Million (ppm)*. Environmental authorities had set a discharge threshold of 1 ppm. Meeting that threshold required implementing a treatment process, but no single off-the-shelf solution exists for PFAS: the right approach depends heavily on the specific water composition, flow rates, and site constraints.
The client needed a rigorous, on-site pilot test to identify which combination of technologies would work, and at what cost.
* To put the numbers in context: ppm stands for parts per million, a unit used to measure trace concentrations in water. One ppm is equivalent to one milligram per litre, or roughly one drop of a substance dissolved in 50 litres of water.
What Revalio delivered
Revalio was brought in as the specialist operator, subcontracted to commission, run, monitor, and report on a mobile PFAS treatment test bench developed by Waterleau. The unit, housed in a 40-foot container, was designed to test multiple treatment configurations in sequence and in parallel, producing comparable data that could inform a permanent treatment decision.
Over eight weeks on site, Revalio handled:
Commissioning and start-up of the full treatment unit, including pre-treatment, membrane systems, adsorption columns, and instrumentation.
Day-to-day operation of the pilot, including adjustment of operating parameters, cleaning-in-place (CIP) procedures, and membrane management.
Systematic sampling and testing across multiple configurations, working with a specialist laboratory to track PFAS concentrations at each stage of the process.
Technical reporting, documenting performance data, anomalies, and recommendations for each treatment technology tested.
How the treatment tests work
The test bench was designed as a modular treatment train, allowing different process combinations to be tested on the actual site water. The main stages were:
Pre-treatment. The incoming water was conditioned through a manganese filter and a twin softener to remove hardness and reduce fouling risk downstream. This step proved essential: the raw water contained high levels of calcium sulphate, which posed a significant scaling risk for the membranes.
Concentration via Closed Circuit Reverse Osmosis (CCRO). Rather than a conventional reverse osmosis pass, the system used a closed-loop batch approach. Water is circulated and concentrated in cycles until a target recovery rate is reached, then the concentrate is flushed and the cycle restarts. This approach provides more operational flexibility and reduces biofouling and scaling compared to continuous RO, since the changing conditions in the concentrate loop discourage microbial growth and crystal formation. It also reduces energy consumption, as the feed pump only needs to handle the permeate flow rather than the full recirculation volume.
Adsorption on ion exchange resins and activated carbon. The concentrated PFAS stream was then passed through columns of selective ion exchange resins, with and without activated carbon pre-treatment. Two different resins were tested at varying flow rates and on different feed streams (raw water versus concentrate), producing a clear dataset on resin lifetime, saturation behaviour, and the comparative effect of activated carbon.
Testing confirmed that selective resins can bring PFAS concentrations below threshold values, but their saturation is accelerated by high sulphate concentrations, which has a direct impact on operational costs. Pre-concentrating with the CCRO before feeding the resin columns showed a measurable positive effect on resin lifetime.
Results
✓ TFA successfully reduced from 8 ppm to 0.6 ppm using RO membranes, well below the 1 ppm regulatory limit.
✓ The CCRO approach demonstrated strong flexibility and lower scaling risk compared to conventional RO, with clear performance data to support its selection.
✓ Ion exchange resins confirmed effective at achieving compliance, with activated carbon providing a beneficial pre-treatment effect on resin colour and longevity.
✓ Pre-concentration of the PFAS stream before adsorption shown to extend resin lifetime, reducing long-term operational costs.
✓ Full test report delivered, giving the client the evidence base needed to design and commission a permanent treatment installation.
Facing similar challenges?
If your site is dealing with PFAS contamination or tightening discharge standards, Revalio can help you find and validate the right treatment approach.