In the not too distant past, urban growth and development focused simply on expanding urban areas, with little practical regard for the impact of these developments on the neighborhood and the environment. Luckily, things have changed, and we’ve rightly turned our attention to finding more efficient and effective ways to use and protect land and natural resources. Today’s environmentally-sound best practices not only facilitate urban growth and development, they also minimize the harm development activities have on the earth’s resources and ecosystems. Leading this important effort is a small but growing number of individuals, government agencies and companies that have chosen to develop and implement best management practices that minimize the environmental footprint of their day-to-day activities — from purchasing raw materials to recycling waste products.

Green Practices

Rather than continue historic patterns of urban development that increase urban sprawl, these development teams have focused on the remediation and reuse of environmentally impaired properties known as “brownfields.” The objective is to reclaim previously developed property in the urban core. Although challenges arise when renovating and reusing these properties, it achieves an environmental “win-win” — developers get valuable real estate with access to established infrastructure while open space is preserved.

An important aspect of this approach is the remediation of contaminated properties and the mitigation of the impact of the cleanup measures used. In 2009, the U.S. Environmental Protection Agency (EPA) released its “Five Principles for Greener Cleanups,” calling for green remediation — the identification of the full spectrum of possible environmental effects of remediation and the use of best management practices (BMPs) to lessen the footprint of cleanup activities. The EPA asserts that cleanup efforts should result in minimal impact to society by protecting human health in a transparent manner that involves the community at large as well as stakeholders.

Specifically, the EPA stated that site cleanups should:

- Reduce total energy use and the use of non-renewable fuel

- Incorporate renewable forms of energy, whenever possible

- Reduce impacts to water resources by minimizing the use of fresh water

- Reduce the release of air pollutants including greenhouse gases

- Reduce of the use of raw material and the generation of waste requiring landfill disposal through the reuse and recycling of waste materials

- Protect land resources and preserve ecosystems

Laying the Foundation

In the fall of 2010, SCS Engineers implemented these green remediation standards during the cleanup of a 90+ year old brownfields site that was formerly home to a steam-powered electric utility, laundry and railroad yard in the center of Flagstaff, Ariz. The two-month cleanup project included the excavation and offsite disposal of 832 tons of contaminated soil from a structure in which creosote was used to preserve wood. The site was located adjacent to the primary natural waterway in the center of the city, the Rio de Flag. 

Working closely with the city’s Brownfield Land Recycling Program, SCS Engineers held a series of public meetings to inform residents of the intent to use green remediation methods to renovate the property. SCS also incorporated this requirement into the project’s technical specifications and bid documents prepared prior to hiring an excavation contractor. All work was reviewed and approved by the EPA. This helped to lay the foundation for community acceptance and contractor cooperation.

The Real Work

Contractors working at the site were required to usea “stair step” approach to reduce the volume of clean soil removed and the total amount of soil requiring landfill disposal, haul soil to a local landfill rather than a less expensive regional landfill to reduce emission of greenhouse gases and air pollution, collect fill soil in dump trucks during return from the landfill to reduce the impact on local infrastructure and emission of greenhouse gases and air pollution, and utilize idle controls and low sulfur fuel on construction equipment to reduce emission of greenhouse gases and air pollution. Following SCS’ direction, contractors were required to purchase recycled fill soil for backfill to reduce the use of raw material, eliminate impacts to freshwater supplies by utilizing 100 percent reclaimed water for dust control, chip and recycle non-native species of trees removed from the site for local area landscaping material, collect storm water in contact with contamination for offsite disposal to prevent contact with clean water in the Rio de Flag, and protect the  local ecosystem by replanting the site with native grass species.

Results

The project was successfully completed using green remediation BMPs. These produced the following results:

• Reduced the miles driven per trip for each haul truck from 160 to 25 and the total miles driven by project haul trucks from 7360 to 1150 miles (84 percent).
• Reduced diesel fuel consumption (a non-renewable fuel) by 1035 gallons.
• Reduced greenhouse gas emissions by more than 20,000 lbs of carbon dioxide equivalents.
• Reduced fresh water use by 10,000 gallons.
• Reduced the use of raw materials in the form of soil for backfill by 869 tons. Since the fill soil that was used at the site would have been disposed of at a landfill, recycling this material also saved landfill space for material that could not be reused or recycled and extended the life of the landfill.

The project also reduced impacts to area roads and bridges, and green remediation practices reduced overall project cost. Perhaps most importantly, the use of green remediation techniques received positive reviews from the community, as well as city workers, who stopped by the site on their way to and from work to check on progress and view the latest developments.

Everyone Wins

The success of this project had a number of positive implications for the future of green remediation and demonstrated the effectiveness and viability of EPA’s principles.

This project proved that, by being creative, it is possible to achieve green remediation goals. Best management practices are not limited to those implemented at this site; however, the tactics used during the Flagstaff remediation do represent environmentally sound cleanup measures that can be applied at other sites. Examples like this serve to validate existing EPA guidance and demonstrate that use of green remediation can be beneficial to all parties involved.