Turning Brown to Green

What savvy EHS professionals need to know about dealing with today's soil and groundwater contamination issues to turn a problem “brown” site into a “green” site. These examples demonstrate how you can get greener while reducing your cleanup costs and protecting employee health and the value of your property by knowing what to look for.

A shopping center in Chicago's western suburbs was contaminated with high concentrations of chlorinated solvents from past dry cleaning operations. The property was being sold and the seller agreed to retain full liability for cleaning up the contamination.

However, the cleanup was complicated by ongoing business operations and a high school right next door. This project presented a challenge in cleaning up a large amount of contaminated soil without the disruption to business. Not to mention the high cost of traditional “dig-and-haul” remediation.

Previous cleanup attempts had focused on the installation of a conventional soil vapor extraction system consisting of numerous vapor recovery wells. However, the chemical in question, Perk, is a very difficult type of contaminant to remove from the ground due to the tight clay soils found in the Chicago area.

Consequently, after 4 years and thousands of dollars spent, the system had only removed a small quantity — approximately 200 pounds or 10 percent — of the residual solvents from the soils on site.

A NEW TECHNOLOGY

There is another creative, more cost-effective and sophisticated option that produces far better cleanup results in turning a “brown” site “green.” It involves using an alternative remediation technology that ideally is suited for this type of scenario: electrical resistive heating (ERH).

The ERH system uses electrical power to heat the soil to the boiling point. The resulting vapors (and contaminants) are then extracted and treated. The use of this system resulted in successfully removing the vast majority of the remaining 2,200 pounds of contamination in a very short time. This timely and economical solution was completed within several months, rather than years, and reduced the contamination by an impressive 96.5 percent.

In addition, it was completed at a cost one-third less than traditional methods, with the added benefit that business operations continued virtually uninterrupted during the entire process.

The take-away here is to know that certain types of soil contamination necessitate a different cleanup approach to get the desired results. You must be able to implement the right remediation technology for the particular site conditions.

In this case, the less expensive and time-saving cleanup strategy permitted the owner to obtain a No Further Remediation (NFR) Letter from the Illinois EPA, which gave the site a clean bill of health and permitted the expedited sale of the property. The property owners were able to go from “brown” to “green” while saving “green” ($$).

PROTECTING THE VALUE OF PROPERTY

Another “brown” to “green” issue involves vapor intrusion. Knowing about vapor intrusion, and what types of sites may pose vapor intrusion issues, can help you protect the value of your building and the air quality of its inhabitants, thus avoiding potentially serious liability issues.

Vapor intrusion revolves around the risk of vapors from certain types of contaminants, either in soil or groundwater, traveling through the subsurface and into a building's interior air space, thereby threatening human health and safety. Vapor intrusion is not a problem on every site, but can be an issue on sites with previous dry cleaning and/or petroleum contamination involving volatile organic compounds (VOCs).

Vapor intrusion is a rapidly developing field of study on the national and local level, both from an assessment and regulatory perspective. With the “greening” of America, vapor intrusion has taken its place alongside indoor air quality as an item of concern for building owners and managers.

New national standards for dealing with vapor intrusion were recently released by EPA. The Illinois EPA also is working on developing vapor intrusion regulations, scheduled for release early next year. Vapor intrusion is the dispersion of vapors from certain types of contaminated soil and groundwater. These vapors can travel up through the subsurface and into buildings (both onsite and off) and pose a threat to occupants. The new standards follow a tiered approach that begins with an initial survey during the course of conducting a Phase I environmental site assessment, in order to identify potential issues up front.

So why is vapor intrusion a problem? Vapor intrusion can affect other buildings in the area far from the source of the contamination. In addition, vapor migration is not as predictable as groundwater flow, as vapors can even flow “uphill” through utility pathways. The impact of vapor intrusion on human health can lead to significant liabilities for owners and have a negative impact on the value of the property.

A vapor intrusion investigation recently was completed on a suburban Chicago commercial office building that was adjacent to a historic dry cleaner operation. The lender involved in the transaction was very concerned about the possibility of vapor intrusion threatening the health and safety of the existing and surrounding building inhabitants, as well as the potential impact on the value of the building that they were using as collateral.

To keep costs down, the investigation was completed in conjunction with a Phase I environmental assessment and a Phase II subsurface investigation. Air samples were taken below the slab in addition to the soil borings. The result: neither the soil or air samples revealed the presence of VOCs associated with the dry cleaning operations.

The lender now had a comfort level and the client was able to proceed with the purchase of the property. The take-away here is that it's important to know which types of sites fit the profile for vapor intrusion issues, and to understand that a small investment during the initial due diligence process can help protect against big liability exposure down the road.


Russ Chadwick is a professional geologist with 20 years experience in the environmental field. He has an extensive background addressing challenging soil and groundwater issues with creative and cost-effective remediation solutions and getting them through the regulatory process to successful closure. He is the midwest regional vice president for Environmental Services for Bureau Veritas North America (http://www.us.bureauveritas.com).

A TASTY APPROACH TO CORRECTIVE ACTION

Remediation objectives in Illinois are established using a risk-based process referred to as TACO, or the Tiered Approach to Corrective Action Objectives. TACO requires the consideration of several potential routes of exposure, including inhalation, ingestion and the potential for groundwater impact.

The property owner in the case of the Chicago shopping center agreed to maintain an asphalt road (i.e., an “engineered barrier”) to eliminate the inhalation and ingestion pathways. In addition, a deed restriction prohibiting the installation of potable water supply wells was placed on the property to eliminate the potential for groundwater ingestion.

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