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Water Treatment
Following the 2018 3M Settlement with the State of Minnesota, the city took immediate action to develop a short and long-term plan to deliver the highest-quality water possible to the community.
For project updates, be sure to check out the Water Treatment Plant and Pipeline Project website.
Temporary Water Treatment Plant
Woodbury is making way for a new permanent Woodbury Water Treatment Plant and associated infrastructure to serve the growing community. In the meantime, an expedited plan and construction of a temporary Water Treatment Plant was completed in 2020 and expanded in 2022 to serve the community with drinking water that meets all current state standards.
The plant, located near the intersection of Valley Creek Road and Tower Drive, is treating water from six of the city’s 20 wells to meet water quality standards and guidelines for per- and polyfluoroalkyl substances (PFAS) using granular activated carbon (GAC). The temporary Water Treatment Plant is expected to be in operation until a long-term water treatment solution can be implemented.
In addition, to ensure the best solutions for technology and operation of the permanent Woodbury Water Treatment Plant, a pilot study of GAC and Ion Exchange technologies (both proven to successfully treat for PFAS) is located inside the temporary water treatment plant and will inform decisions for the permanent water treatment plant.
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.
At its Jan. 8, 2020, meeting, the Woodbury City Council took actions to expedite the construction of a temporary water treatment facility to treat three of the city's six water wells currently exceeding water quality standards and guidelines for per- and polyfluoroalkyl substances (PFAS). On February 3, the Minnesota Department of Health gave verbal notification that a seventh well exceeded the health-based guidelines for PFAS and this well was immediately removed from service (official notice was received Feb. 21).
The temporary water treatment plant, which typically takes about 18 months to two years to construct, was completed in about five months. In order to meet peak summer demand, it was critical the temporary treatment facility was operational as quickly as possible.
In early 2022, MDH issued a health advisories for two additional production wells, one in January and one in February. Of the city's 19 production wells, five of the wells with health advisories remain out of service.
The city would not be operating the facility today without the work and cooperation of the State of Minnesota, 3M, the City Council, numerous city staff, our engineering consultant teams, and the construction expertise of the project contractor.
As part of the process of designing the permanent Woodbury Water Treatment Plant, a pilot study is being conducted at the temporary Water Treatment Plant to evaluate performance of various PFAS treatment technologies. The overall goal of the pilot study is to assess iron (Fe) and manganese (Mn) pretreatment alternatives and PFAS treatment alternatives.
Study Objectives
- Recommend whether Fe/ Mn treatment upstream of PFAS adsorption is required, provides an operational benefit for life cycle of PFAS media, or overall net benefit for treatment of PFAS.
- Recommend Fe/Mn media, oxidant, and filter loading rate.
- Recommend a preferred PFAS adsorptive media based on performance, operations and maintenance, supply, and costs.
- Identify potential water quality characteristics that may impact the long-term treatment performance.
- Determine operations and maintenance requirements related to the treatment including chemical consumption, water quality monitoring plan, maintenance and operational requirements, and operator qualifications.
- Confirm site-specific criteria for the design of the full-scale treatment upgrades and to inform the development of capital and operations and maintenance costs.
The design and construction of the temporary Water Treatment Plant and associated infrastructure was completely funded by the 2018 3M Settlement with the State of Minnesota. The city continues to advocate on behalf of the community for funding of the permanent Woodbury Water Treatment Plant and associated infrastructure need to service the residents and businesses of Woodbury for many years to come.
The technology and science behind the temporary Water Treatment Plant (and pilot study) as well as the future permanent Woodbury Water Treatment Plant is exciting and educational. If you are interested in learning more about it or organizing a tour of the plant for a group or organization, please send an email to Jason Egerstrom, Communications Manager.
Long-term Solution: Woodbury Water Treatment Plant
As an advocate for the residents of Woodbury, the city is working on developing a solution that will serve the community today and long into the future, but it may take time. This is the largest project the city of Woodbury has undertaken, and it stretches across the whole community. Careful and thoughtful design work will take place over the next several years.
The ultimate goal for the permanent Woodbury Water Treatment Plant is to provide water that meets current and future standards, for a long time, without doubt. Woodbury is working with national engineering firms to develop the best possible treatment technologies and system improvements to treat not just PFAS but other emerging contaminants for the foreseeable future.
After development of a Preliminary Engineering Report, the city approved a plan to treat ALL groundwater wells through a 32 MGD million gallons per day (MGD) water treatment plant, addition of two new wells, and more than 14 miles of distribution pipelines. With this plan, any future PFAS regulatory action, after the new long-term water treatment plant is built, would not affect the city’s ability to successfully meet current and projected drinking water standards.
In August 2021, the City of Woodbury purchased a parcel of land south of Hargis Parkway and east of Radio Drive for the future construction of the Woodbury Water Treatment Plant.
Costs associated with the purchase of the property were fully funded by the State of Minnesota and 3M settlement agreement. Total costs for the facility construction are in development. For several years, the city has been advocating for the majority of costs associated with treatment for PFAS to be funded through the settlement agreement. Updates on costs and treatment technologies will be forthcoming.
The city of Woodbury’s drinking water system consists of 19 raw water wells, more than 300 miles of water main and storage in four water towers, one standpipe, and one ground storage reservoir. All raw water wells are treated with fluoride and chlorine for dental health and disinfection, respectively. Two wells (Well No. 14 and 15) are treated with polyphosphates to sequester iron and manganese corrosion. The current water supply system produces an average of 6.9 million gallons per day (MGD) with a maximum day water demand exceeding 18.0 MGD in recent years and a historical peak of 23.0 MGD in 2006 and 2021 as a result of peak summer daily system demands.
The long-term plan for the city’s water system includes moving to a hydraulic break system which would include adding a clearwell for storage at the plant and a new pump station. These modifications to the city’s system will provide equal water quality to ALL Woodbury residents.
The city continues to advocate for 3M Settlement dollars to be released expeditiously and to cover treatment of all Woodbury water supplies. The city is also working with state and federal elected officials to capture funding opportunities. The city understands the importance of this infrastructure and is working diligently to fight for responsible funding investment by the state from the settlement and minimize financial impacts to residents.
The State of Minnesota drafted a Conceptual Drinking Water Supply Plan that conceptualized long-term alternatives for addressing PFAS contamination in drinking water throughout Washington County, including partial treatment, well modifications, pipelines, and other miscellaneous items for the City of Woodbury. However, the Water System Master Plan developed by a consultant on behalf of the city, identified gaps in needs and funding as it related to the city’s current water system and projected demands. To date the city has successfully advocated on behalf of the city to secure:
- System-wide treatment
- Increased Tamarack wellfield capacity
- Revised demand from 28.2 to 32mgd based on updated population and demand projections
- Increased pipeline size from Tamarack wellfield
- Addition of a Water Treatment Plant Booster Pump Station and 4MG Clearwell
In total the city’s advocacy with the state has yielded over $62 Million dollars in assets for the city. The city continues to work on addressing additional funding gaps and opportunities.
Home Water Treatment
Private water well owners or residents interested in treating the water after it reaches their home can learn more on the Minnesota Department of Health's website.
Residents who have questions about their private water supply well and whether it is impacted by this change should contact MDH.