Reaping the Benefits of Brownfield Redevelopment

Challenge

A 100-acre site in Andover, Minnesota, which once served as an automobile salvage yard, posed serious environmental risks due to extensive contamination. Over years of operation, hazardous substances such as petroleum, diesel, gasoline, heavy metals, and asbestos had seeped into soil, contaminating soil, groundwater, and soil vapor across the property, designating the area as a brownfield site. Of particular concern was the area surrounding a car crusher in the northeast corner, where significant petroleum contamination had been identified. This contamination rendered the property unsafe for its intended future commercial and light industrial development.

Before the site could be transformed, a comprehensive environmental assessment and remediation was required. The goal was to properly manage contaminated soil excavated for the redevelopment, mitigate environmental risks from remaining contaminants, and restore the land to a condition suitable for redevelopment. Without addressing these issues, the contaminants could have long-term environmental and public health impacts, impeding the community's growth and economic development potential.

Solution

To address these challenges, SEH was contracted to provide a full range of investigation, remediation, and redevelopment services. Partnering closely with the City of Andover, the team conducted detailed environmental assessments to fully understand the extent and distribution of contamination. Using data gathered from site assessments, over 14,360 cubic yards of impacted soil was excavated and either disposed of at a landfill or used below the roadway with regulatory approval.

After the initial excavation, additional soil borings were conducted to monitor any remaining groundwater and soil vapor contamination. These post-excavation assessments evaluated the risk of vapor migration into future buildings and measured the effectiveness of groundwater dewatering and contamination removal. This thorough approach ensured that all environmental hazards were fully addressed, preparing the site for safe and successful redevelopment. Following cleanup, the Minnesota Pollution Control Agency issued a No Further Action and regulatory closure for the remaining contaminants.

With the remediation process complete and immediate hazards mitigated, the project moved forward with infrastructure improvements to support the planned commercial and light industrial use. This included comprehensive street, utility, and site grading enhancements. A 42-foot-wide roadway, stretching approximately half a mile, was constructed to facilitate access. The boulevard design featured a sidewalk, multi-use trail, street lighting, and landscaping to create an inviting and functional environment for both pedestrians and vehicles.

Overall, the project required careful coordination between site improvements, contamination cleanup, and on-site wetland mitigation efforts. SEH worked closely with adjacent properties and the local watershed district to reduce any potential environmental impacts during the process. As a result, the once contaminated and unused property was transformed into a safe, commercially viable space, setting the stage for Andover's continued growth and development.