Temporary Water Treatment Facility

Water Treatment FacilityAs of June 2020, the temporary water treatment facility is online and capable of producing water at full designed capacity. The facility, located near the intersection of Valley Creek Road and Tower Drive, is treating water from four wells to meet water quality standards and guidelines for per- and polyfluoroalkyl substances (PFAS) using granular activated carbon.

The temporary water treatment facility is expected to be in operation until a long-term water treatment solution can be implemented in the next five to seven years. Funds for the long-term solution are expected to be available from the $720 million settlement the state received from 3M in 2018. 

2022 Expansion

In anticipation of additional wells potentially receiving health risk advisories from MDH, at the end of 2021 the city embarked upon the expansion of the temporary facility to increase its water treatment capacity. 

As of February 2022, two additional wells received health risk advisories from the MDH and are now included in the expansion process and will be connected to the facility. These wells are expected to be put back into service in summer 2022. 

Approximately half of the expansion process will be completed within the existing facility. Connection of the two additional production wells to the site will result in temporary traffic changes on Tower Drive and temporary closure and rerouting of trails. Connection of the wells will be completed with horizontal boring to minimize impact the surrounding area but will still require points of excavation.

  1. About GAC Treatment
  2. Project Background
  3. Site Plan
  4.  Nature Preserve Impacts

Activated carbon is commonly used to adsorb natural organic compounds, taste and odor compounds, and synthetic organic chemicals in drinking water treatment systems. Adsorption is both the physical and chemical process of accumulating a substance, such as PFAS, at the interface between liquid and solids phases. Activated carbon is an effective adsorbent because it is a highly porous material and provides a large surface area to which contaminants may adsorb. Activated carbon is made from organic materials with high carbon contents such as wood, lignite, and coal; and is often used in granular form called granular activated carbon (GAC).

GAC has been shown to effectively remove PFAS from drinking water when it is used in a flow through filter mode after particulates have already been removed. GAC can be 100 percent effective for a period of time, depending on the type of carbon used, the depth of the bed of carbon, flow rate of the water, the specific PFAS you need to remove, temperature, and the degree and type of organic matter as well as other contaminants, or constituents, in the water.