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PFAS Removal from Industrial Discharge and Drainage Water

Reference project

Water treatment .

Challenge

Location

Sweden

Application

PFAS treatment in final effluent discharge at industrial wastewater treatment plant

Industry

Industrial wastewater

Capacity

15 m³/h

Performance

PFOS: 99.97% PFHxS: 99.6% PFOA: 82%

Solution facts.

Mellifiq delivery:

Containerized polishing system using GAC filtration and pre-filtration media

Introduction.

A Mellifiq end-of-pipe plug-and-play delivery for PFAS removal using multi-stage adsorption processes

The wastewater treatment facility is designed to treat process water generated from airport operations. The treatment plant includes several conventional treatment steps such as chemical precipitation, pH adjustment, flocculation, lamella separation, and filtration.

These processes are effective for removing suspended solids, oils, and other bulk contaminants typically associated with airport runoff and airport-related wastewater. However, they are not designed to target dissolved micropollutants such as per- and polyfluoroalkyl substances (PFAS), which are increasingly regulated due to their persistence and environmental impact.

As regulatory requirements have become more stringent, the need to address PFAS in treated water has become acritical challenge for wastewater treatment facilities.

The problem.

PFAS contamination has been identified in the treated wastewater at the facility, with elevated concentrations remaining after conventional treatment processes. PFAS contamination at the site originates from the historical use of firefighting foam (AFFF) during fire training activities.

This has led to long-term contamination of soil and surrounding water systems, with PFAS subsequently detected in wastewater streams entering the treatment process. The existing treatment system, designed to remove suspended solids, oils, and bulk contaminants, is not intended to remove dissolved micropollutants such as PFAS. As a result, PFAS compounds remain in the treated water despite multiple treatment steps.

Laboratory analysis of treated wastewater prior to PFAS polishing confirmed elevated levels of several PFAS compounds, including PFOS (2000 ng/L), PFOA (510 ng/L), and PFHxS (290 ng/L), with a total PFAS11 concentration of approximately 5100 ng/L. These concentrations highlight the limitations of conventional treatment and the need for a dedicated polishing step capable of reducing PFAS levels prior to discharge, in accordance with applicable regulatory requirements.

The solution.

To address this challenge, a containerized polishing system based on granular activated carbon (GAC) adsorption was implemented downstream of the existing treatment plant.

The system was designed as a compact and modular unit to enable straightforward integration with the existing infrastructure. It includes a pre-filtration step to protect down stream processes, followed by two parallel activated carbon filters.

This configuration ensures sufficient contact time while allowing operational flexibility and redundancy. Activated carbon adsorption is a well-established method for removing PFAS, particularly long-chain compounds, by binding contaminants to the carbon surface.

By introducing this targeted treatment step, the system complements the existing treatment processes rather than replacing them. The solution enables continuous operation and stable performance under varying flow conditions, making it suitable for real operating environments such as airport facilities.

Evaluation.

Performance testing was conducted by an accredited laboratory to verify the system’s effectiveness in removing PFAS compounds under real operating conditions. The results demonstrated significant reductions across several key parameters.

Parameter	Before Treatment	After Treatment	Reduction
PFOS	2000 ng/L	0.54 ng/L	99.97%
PFHxS	290 ng/L	1.2 ng/L	99.6%
PFOA	510 ng/L	90 ng/L	82%
Sum PFAS11	5100 ng/L	1400 ng/L	73%

The results demonstrate significant removal of several PFAS compounds such as PFOS and PFHxS, alongside a substantial reduction in total PFAS concentrations.

Multiple samples confirmed consistent performance, demonstrating the system’s ability to effectively complement existing treatment processes and reduce PFAS levels to support compliant discharge under site-specific regulatory conditions, including ABVA.

Overall, the implementation demonstrates how a targeted polishing step can effectively complement existing treatment processes, enabling reliable removal of PFAS and supporting long-term compliance in complex wastewater applications.