BaytownTownship Ground Water Contamination Site

This page provides information about cleanup of the Baytown Township Ground Water Contamination Site (Site). More detailed information about this Site can be found in technical reports primarily available from the Minnesota Pollution Control Agency (MPCA). Some Site reports are also available from the Minnesota Department of Health (MDH).

Where is the Site

The Site is located in central Washington County, Minnesota. The Site is defined essentially by the MDH’s Special Well Construction Area (SWCA). The SWCA was established to regulate the construction of new wells. At their widest extent, the SWCA and the Site are approximately bounded on the north by 50th Street, and on the south by 20th Street. The contamination extends from the eastern portion of the City of Lake Elmo through BaytownTownship, WestLakelandTownship and the City of Bayport to the St. Croix River as shown in the map below.

Map of Site

Additional maps are available on the Minnesota Department of Health's Web site

What is the Contamination?

The main contaminant of concern that has been released to ground water at the Site is 1,1,2-trichloroethene (TCE). The TCE plume is located within the Site and is approximately five miles long and covers about seven square miles. The TCE plume affects four major ground water aquifers. There are approximately 650 homes and several businesses located within the TCE plume that are served by private wells.

What does the remedy include?

The MPCA selected a remedial action for releases, or cleanup, at the Site that will protect the public health and welfare and the environment. The remedial action was set forth in the July 2007 Record of Decision (ROD) Amendment. The major operable unit components of the selected remedy include the following:

  • Operable Unit 1 (OU1) – Continued monitoring of private wells, sampling of private water supply wells, and installation, change out, and maintenance of granular activated carbon (GAC) filter systems as previously designated in the original May 2000 ROD.
  • Operable Unit 2 (OU2) – An air stripping treatment system at Bayport Municipal Well #2. The City of Bayport is responsible for ongoing operation and maintenance of this air stripper.
  • Operable Unit 3 (OU3) – Containment and treatment of TCE in ground water at the primary source zone– a former metal fabricating shop located at 11325 Stillwater Boulevard in Lake Elmo. A two-pronged approach is being implemented for OU3 as follows:
  • Containment (Hydraulic barrier- OU3)
    In early March, the MPCA completed construction on a hydraulic barrier to capture or contain the TCE plume and prevent off-property migration of contaminated ground water. The barrier consists of “extraction” wells spaced such that their influence overlaps and collectively captures the contamination before it can migrate off the property. The extracted water is then treated by air stripping to remove the TCE from the water.
    The pumps for the barrier system were started up on March 17, 2008. This barrier is anticipated to operate continuously at approximately 70 to100 gallons per minute with the exception of down time for maintenance or tests. Its purpose is to control the ground water gradient such that high concentrations of contamination are unable to continue to migrate to the east. The barrier will likely operate for at least five and maybe beyond 10 years.
    The four extraction wells will recover the ground water and pump it to a low-profile air stripper located within a treatment building. The air stripper will remove more than 99 percent of TCE from the incoming water. The water will be treated to less than 1 microgram per liter (ug/L) which is below the MDH Health Risk Limit of 5 ug/L. The water will then be discharged back to the soil using horizontal wells approximately 25 feet underground.
  • Source treatment (OU3)
    Ground water beneath the source zone will be treated using a treatment train approach to the extent practical. Treating the source area directly will help to minimize the necessary duration of the hydraulic barrier and ultimately the time downgradient wells must remain on whole-house granular activated carbon (GAC) filters. In-situ chemical oxidation is currently being evaluated as a four-month a pilot test has just been completed.

How far along is the cleanup?

  • Operable Unit 1 (OU1) – The MPCA continues to monitor and sample approximately 630 private wells affected by the Site’s TCE plume. For wells on properties platted before April 9, 2002, where concentrations of TCE exceed the Health Risk Limit of 5 micrograms per liter, the MPCA provides bottled water until a whole-house GAC filter system can be installed. Additionally, the MPCA does future change outs and maintenance of these GAC filters. However, for wells on properties platted after April 9, 2002, bottled water service and GAC filters are not provided by the MPCA, but by the homeowner in accordance with local ordinances.
  • Operable Unit 2 (OU2) – Since spring 2007, ground water extracted by Bayport municipal well #2 has been treated with an air stripper prior to its entrance into the Bayport municipal water supply. The MPCA funded the design and construction of the treatment system through a grant agreement with the City of Bayport. MDH continues to monitor all Bayport municipal wells to ensure that levels are safe.
  • Operable Unit 3 (OU3) – Containment and treatment of the primary source area:
  • Containment (Hydraulic barrier)
    The hydraulic barrier construction is now complete. As of mid-March, a total of four extraction wells are pumping contaminated water to a treatment building which houses the air stripper. The air stripper transfers the volatile TCE from extracted ground water to the air. Carefully evaluated and modeled air emissions are predicted to meet applicable air quality standards. Monitoring of actual emissions will be conducted to confirm modeled results. The treated clean water is discharged below the surface and allowed to percolate back to the aquifer.
  • Source treatment
    In November 2007, a pilot test was initiated using in-situ chemical oxidation to treat ground water underlying the source zone. A total of seven injection points were used. The vertical treatment zone extended from 40 to 60 feet below ground surface. Approximately 2300 gallons of sodium permanganate were injected in to the ground water. Effectiveness monitoring of the pilot test is completed. Based on the results of the pilot test, a final feasibility study report will be prepared and final design for the source area treatment will be completed. In addition to in-situ chemical oxidation, in-situ bioremediation may be used to provide a long-term carbon source to further degrade the TCE in ground water at the source zone. Full-scale treatment of the source zone is anticipated to be conducted in 2008. More details of the actual full-scale treatment scenario will be provided in future updates.

Where Can I Get More Information?

All documents prepared during the investigation, selection, design and construction of the remedy are available at the MPCA, 520 Lafayette Road N., St. Paul, MN55155 for review.

Selected documents are also available for review at the Bayport Public Library, 582 N. 4th Street, Bayport and the Rosalie E. Wahl Library, 3479 Lake Elmo Ave. N, LakeElmo.

Staff Contacts

  • Dan Card, Project Leader, 651-297-8379,
  • Kurt Schroeder,Hydrogeologist, 651-296-8593,
  • CoriAhna Rude-Young, Public Information, 651-296-5965,
  • Minnesota Department of Health (health issues or well issues): Jim Kelly, Health Risk Assessor, 651-201-4910