Our client is an industrial waste management and recycling facility in Western Europe. Historic activities had contaminated the local groundwater and leachate at this site with extremely high levels of ultra-short-chain PFAS (the smallest, most challenging PFAS molecules). Measured concentrations were on the order of 5–10 ppm (mg/L) – astronomically above typical environmental levels.

Moreover, the water had a very high salinity (~8000 µS/cm conductivity) and other organic contaminants, making treatment difficult.

Conventional approaches (Granular Active Carbon-GAC, standard resins) are known to have low effectiveness for ultra-short-chain PFAS and would incur prohibitive costs at such loads. The client sought a solution that could handle the complex matrix (high salt and organics) and drastically reduce PFAS, ideally including on-site destruction to avoid simply transferring the problem to another waste stream.

Multiple treatment train based on IEX and and GAC

Waterleau deployed its PFAS Test Bench to the site for a rigorous pilot campaign. Over a 2-month test program, our engineers evaluated multiple treatment train configurations to find the optimal approach. The pilot was designed with robust pre-treatment (water softening and multimedia filtration) to mitigate scaling and fouling from the high salt content.

We then tested a series of advanced process combinations, including Closed-Circuit Reverse Osmosis (CCRO) for high-recovery separation, granular activated carbon, and two types of ion exchange resins – in various multi-stage sequences – to determine which would best remove the diverse PFAS present.

In total, eight different treatment trains (up to 5 stages each) were trialed and evaluated during the pilot. Throughout, Waterleau collected data on PFAS removal efficiency, resin exhaustion rates, membrane performance, and more, while also tracking the operating costs associated with each approach.

Reduction of PFAS treatment cost with 50% compared to a single technology approach

The pilot yielded a clear, data-driven solution. By combining technologies in a smart way, we demonstrated that the PFAS treatment cost could be reduced by a factor of 2 compared to a single-technology baseline.

In other words, the hybrid approach achieved the target PFAS removal at roughly half the cost of any stand-alone method – a huge win given the client’s high contaminant levels.

The pilot gave the client confidence to move forward with a full-scale design, knowing the exact performance and cost of the selected multi-technology treatment train. This case underscores Waterleau’s ability to tackle “impossible” PFAS – like ultra-short-chain compounds in a harsh waste stream – by leveraging our unique pilot toolbox and innovative thinking.