In 2004, PFAS were first found to have contaminated drinking water supplies in parts of the eastern Twin Cities. Over the last 15 years or so, PFAS have been discovered in Woodbury’s groundwater supply, and research has been conducted to identify the source and level of contamination. Most of the contamination has been traced to four dumps or landfills in Oakdale and Woodbury, at the 3M manufacturing facility in Cottage Grove, and at the Washington County landfill.
On February 20, 2018, the State of Minnesota settled its lawsuit against the 3M Company in return for a settlement of $850 million. Minnesota’s attorney general sued 3M in 2010 alleging that the company’s production of chemicals known as PFCs (now commonly referred to as PFAS) had damaged drinking water and natural resources in the southeast Twin Cities metro area.
In May of 2019 Woodbury Submitted an expedited project request to the State of Minnesota to complete a distribution system PFAS mitigation feasibility study to support the sustainable operation of the water system while plans for a final treatment system are developed. It was important to Woodbury that they understand the potential impacts of additional well contamination and could react quickly should regulations change or contamination levels increase. A key portion of this feasibility study was to develop a hydraulic model focused on PFAS mixing and system operational dynamics which would allow Woodbury to further evaluate the well hydraulics and mixing dynamics within their distribution system.
Upon completion of the mixing analysis in October of 2019 AE2S discovered that Woodbury’s drinking water system did not completely mix and they could potentially experience levels of PFAS above acceptable health index levels. Following this discovery Woodbury approached the state of Minnesota with a formal request for a temporary WTP. The goal of the WTP would be to eliminate the risk of regulatory changes or increasing contaminate levels in Woodbury’s wells until a final WTP was operational.
Following negotiations with the state and the identification of a temporary WTP site Woodbury was awarded a grant of $8,725,000 to design and build a temporary WTP capable of treating 3,800gpm. AE2S jumped into action in early 2020 to begin planning for the design and construct a temporary WTP with a goal of treatment being operational by June 1, 2020. In addition to AE2S beginning an expedited design process, Woodbury determined that this was an emergency and declared a city emergency which allowed them to utilize a unique CMAR (Construction Manager at Risk) contracting method not yet allowed in Minnesota.
AE2S assembled a team that was ready to deliver a project in record time. Due to the expedited nature of the project AE2S felt that a good contracting partner would be essential. AE2S scheduled and facilitated interviews with three (3) construction partners in mid-January and ultimately Woodbury selected Rice Lake Construction Group to team with. The team jumped into action establishing a guaranteed maximum price (GMP) from Rice Lake Construction. The project team (City of Woodbury, AE2S, and Rice Lake) met weekly to collaboratively develop three (3) separate design packages and begin portions of the construction in order to meet the schedule requirements. Rice Lake began excavation on site on February 24th. The underground piping and foundation work was completed by April 1st just in time to allow GAC pressure vessels to be delivered on site with the precast wall panels the first week of April. Once the building was erected Rice Lake worked diligently with the engineering team to complete the necessary internal components of the WTP and commission the pressure vessels so that the WTP successfully met the June 1st substantial completion date and was able to produce PFAS free water. Final project items were completed following substantial completion and the entire project was successfully completed under budget and closed out by the end of 2020.