Marshfield Utilities Tackles PFAS: Temporary Treatment Success

Challenge

Like many communities across the country, the City of Marshfield, Wisconsin, was concerned with the health risks associated with per- and polyfluoroalkyl substances (PFAS) exposure. In response, Marshfield Utilities participated in voluntary testing of its drinking water supply. PFAS was discovered at each of the Utility’s south wellfield wells at concentrations up to 25 times the maximum EPA contaminant levels, well above Wisconsin Department of Health Services (DHS) advisory standards.

The south wellfield wells supply the City’s Southside Booster Station. Due to the high levels detected, the Utility ceased using the station immediately – straining the water system's capacity, especially during high-demand summer months. Adding to the complexity, the project had to be completed on an accelerated timeline due to a scheduled filter media replacement at the Utility's water treatment plant, which required a plant shutdown.

Marshfield Utilities had plans to construct a new permanent facility capable of treating PFAS, but in the interim, they needed to swiftly implement a temporary PFAS treatment solution to restore a safe water supply to the community while facing tight timelines, space constraints, and unique climate conditions.

Solution

To address these challenges, Marshfield Utilities partnered with SEH to conduct a feasibility study, after which the team designed and implemented an innovative temporary water treatment system. The strategy comprised several key components:

Mobile Treatment System Design

The SEH team devised a creative approach by utilizing a refurbished refrigerated trailer to house the temporary treatment system. This mobile design allowed for rapid deployment and installation, meeting the project's tight timeline. Despite size restrictions, the team successfully engineered the system to accommodate the equipment needed to meet the 950 gallon per minute operating flow rate of the Southside Booster Station.

Innovative Filtration Technology

SEH engineers selected ion exchange media as the primary means of PFAS removal. They implemented a forward-thinking vessel design that supported the ion exchange media with anthracite, an atypical combination that maximized efficiency. This design ensured that the entire bed of ion exchange media was utilized for PFAS removal, with no wasted media adjacent to or below the vessel underdrain.

Climate-Adaptive Systems for Remote Monitoring

Recognizing the unique weather conditions in central Wisconsin, the SEH team outfitted the trailer with specialized equipment for remote operation. This included automated start and stop capabilities based on water demand, remote monitoring systems, temperature and humidity control, access monitoring and control, and power supply equipment compatible with the existing Southside Booster Station infrastructure.

Collaborative Problem-Solving

The SEH team played a crucial role in fostering collaboration between multiple stakeholders, including Marshfield Utilities, the Wisconsin Department of Natural Resources (WDNR), contractor, and equipment suppliers. This collaborative approach was essential in navigating challenges such as the Build America Buy America Act (BABA) requirements, funding considerations, and the selection of appropriate equipment for the unique project needs and space constraints.

Efficient Project Management

Despite the accelerated timeline, the SEH team ensured that the temporary treatment system was completed not only on time but also 12% under the projected budget. This efficiency allowed the Utility to complete its media replacement project ahead of the high-demand summer season.

Beneficial Outcomes

The implementation of this temporary treatment system yielded significant benefits for the Marshfield community, including the following.

• Water Safety: Post-treatment water samples have shown non-detectable levels of all tested PFAS compounds, ensuring a safe water supply for the community.
• Restored Capacity: The project allowed the Utility to bring the Southside Booster Station back online, meeting the community's water demands without compromising safety.
• Minimal Environmental Impact: The mobile nature of the system allowed for installation with minimal disturbance to the existing environment.
• Future Flexibility: The mobile system can potentially be repurposed for other communities facing similar PFAS challenges in the future.

By implementing a creative design, fostering collaboration, and applying effective project management, the SEH team successfully delivered a solution that addressed Marshfield's immediate PFAS concerns while providing a framework for addressing similar challenges in other communities.

Project Award

• 2024 Utility Achievement Award| American Water Works Association, Wisconsin Section (WIAWWA)