Approaches to cleaning up contaminated property have evolved over time to incorporate new technologies and address new environmental concerns. Due to increased awareness of the potential effects of climate change, individuals from government, industry and academia have begun to examine the impact of a cleanup on greenhouse gas emissions, as well as a broad range of sustainability issues.

EPA Region 3 tackled this subject a year ago by initiating a sustainable remediation pilot with a facility required to perform corrective action under RCRA. The purpose of the pilot (see BFN, Dec. 2007) was to determine whether the RCRA program could incorporate measures of sustainability into the remedy decision process.

This new emphasis required the pilot team to examine the environmental outcome of a cleanup more broadly and to consider the benefits of specific cleanup approaches to address those outcomes.

The facility proposed a credit and debit matrix framework which factored in a number of quantifiable components to evaluate the sustainability of a potential remedy. This matrix went through several iterations in a collaborative forum, but always included greenhouse gases, energy use and resource use. Combined with life cycle analysis (see previous article), the matrix was used to evaluate the environmental effects over the duration of the remedy. Although, the matrix is still a work in progress, it served to crystallize a number of issues that require further evaluation.

Some regulators were concerned that a sustainability screening factor would be used as an excuse to limit the scope of cleanups, especially for groundwater. They argued that certain energy-intensive cleanup technologies would never be selected for remedies because of their carbon footprint, even though they may provide the most effective cleanup.

In essence, facilities across the country would use the tool to support “no action” as the preferred remedy alternative at many sites.

To address this, the pilot team emphasized that a sustainability factor should not trump RCRA’s remedy selection threshold criteria: to protect human health and the environment, control sources and achieve media cleanup goals. The pilot team’s vision was to develop this sustainability assessment to enhance the seven traditional RCRA balancing factors that decision makers use to evaluate remedies that achieve the three threshold criteria. Ideally, the outcome will be a cleanup that maximizes the net environmental benefit.

A major challenge was balancing the overlap between energy use and greenhouse gas output resulting from cleanup activities, while supporting the agency’s preference for treatment policy.

One proposal developed under the pilot was to provide carbon credit for the destruction of contaminants with global warming potential. Under the matrix, a positive credit for contaminant destruction would promote more aggressive cleanup technologies and less long-term maintenance, which is more sustainable.

But there were two major snags with this approach.

In certain scenarios, it would be a stretch to say that a contaminant in the subsurface would eventually be released into the atmosphere, if not destroyed. Additionally, some common contaminants, such as chlorinated volatile organics (e.g. TCE), have low global warming potential. Consequently, the estimated greenhouse gases destroyed through treatment were minimal relative to the carbon output from active remediation.

Another way in which the pilot tried to create a sustainable balance between greenhouse gas output and energy use with active remediation was to increase the list of items considered in the framework, making the two factors less prominent.

At times, there were more than a dozen factors to consider, including NOx, SOx, PM-10, noise, land use, and occupational risk. But this raised questions about the merits of a comprehensive evaluation versus the reality of the agency’s limited resources to verify extensive calculations prior to approving a cleanup. The idea was not to create a protocol that adds process and slows down cleanups.

The sustainability framework evolved as it was applied to three solid waste management units at the pilot site. Certain elements of the matrix were dropped, some were incorporated into the traditional RCRA remedy selection factors and some became part of a new sustainability factor.

Although several challenges still require resolution, the evaluation led to a more informed decision for selecting remedies at the three units. The selected remedies all treat source material and result in energy use and greenhouse gas emissions an order of magnitude lower than the technologies favored before the pilot.

For a site where the cleanup can be chosen presumptively, a sustainable assessment is unnecessary. However, when there are several viable options on the table, quantifying the potential impact will provide better environmental results.

This approach warrants further evaluation by regulators and the regulated community for the positive contribution it can make toward reducing greenhouse gas emissions from cleanups while preserving natural resources and providing long-term protection. It’s just a matter of finding the perfect balance.

Deborah Goldblum is EPA Region 3’s RCRA Corrective Action Revitalization coordinator. Bob Greaves is Region 3’s associate director for the Office of Materials Management. Any views expressed in this article are the views of the authors and do not necessarily represent the views of the U.S. EPA.