National Clothesline

With an estimated 20,000 contaminated drycleaning sites in the United States needing clean-ups, the search for techniques that can get the job done and, perhaps, lower the cost of doing it, is key to ensuring not only the health of the environment but also that of the drycleaning industry.

To capture a snapshot of the current state-of-the art, the State Coalition for Drycleaner Remediation (SCRD) published a survey this spring that looks at the technology trends reported by 28 states in which a total of 1,229 drycleaning sites had been assessed. The SCRD report evaluates clean-up trends across the country from 1999 to 2002, comparing responses from 28 states to those from a similar survey in 1999.

The survey gathered information on technologies for two main areas: assessment and remediation, It also looked at program- and project-specific information concerning contaminant types, general costs, clean-up standards, guidance documents and the lessons learned.

Of the two main areas, SCRD found that remediation has shown more technological change than assessment, which has remained fairly consistent in recent years. Remediation technologies used for soil contamination include SVE, bioventing, excavation, chemical treatment, and thermal. For groundwater remediation, there is air sparging, pump and treat, multi-phase extraction, recirculating wells, bioremediation, chemical oxidation, in-situ flushing, thermal treatment, permeable reactive barrier walls, and monitored natural attenuation.

While standard technologies such as air sparging, pump and treat, multi-phase extraction, and monitored natural attenuation are still being used, bioremediation and in-situ chemical oxidation are becoming important tools for site cleanup, SCRD found.

“New products continue to be introduced that enhance bioremediation and chemical oxidation efforts,” the report said.

In bioremediation, many different products are used to create an environment for optimizing growth of microorganisms. Among the products used by survey respondents were dextrose, ethyl lactate, molasses, sodium lactate, cooking oil, ethanol, Hydrogen Release Compound, Oxygen Release Compound, and potassium lactate.

In chemical oxidation, chemicals are injected into contaminated groundwater to promote a reaction that converts the contaminant to harmless by-products. Survey respondents identified the following products used during chemical oxidation projects: Fenton’s Reagent, hydrogen peroxide, ozone, KMnO4, and NaMnO4.

“Innovative technologies continue to evolve as more research is conducted in the lab and at contaminated sites,” SCRD concluded “The search for a cost efficient and technically effective remediation technology will also continue since site-specific conditions vary greatly at these drycleaning sites. Technologies that work at one site may easily be a great failure at the next site.”

While none of the technologies provides a one-size-fits-all solution, as SCRD noted, even on a single site various approaches may be used — one for the source area, another for the plume contaminant and yet another to finish off the corrective action.

And technology does not solve all the problems. Non-technological obstacles to remediation are many, ranging from uncooperative landowners, tenants, and independent third parties to difficulties in gaining access to the source areas due to buildings, streets, utilities, etc. Other problems are getting permits to do the work, determining whether remediation waste is hazardous and how to dispose of it and even objections to noise from the system operation.

And then there is the question of cost, emphasized by SCRD in its report as “Cost, COst, COSt, COST!!!!!”

“Assessment and remediation technology is changing as consultants come up with innovative ideas to overcome the obstacles,” SCRD concluded. “Geologic and hydrogeologic conditions generally dictate how a site is approached. Field screening techniques, waste minimization procedures and rapid assessment are important for conducting cost effective site characterization. States continue to search for new ways to complete effective, cost-efficient corrective action.”

While site assessment techniques, the other major area examined in the survey, have not changed so much over the past few years, they remain important for understanding how the contaminants were introduced into and move through the subsurface. It’s costly, too, since site characterization tools can be expensive and difficult to use and chlorinated solvent plumes are generally more expensive to assess because chlorinated solvent contamination remains in the soil and groundwater, creating larger, often more complicated contaminant plumes.

Nearly one-fourth of the assessments reported by the states cost more than $100,000; a third were under $50,000 while the rest were between $50,000 and $100,000.

In addition, site assessments face many of the same non-technological obstacles as remediation projects.

The SCRD survey found that the level of assessment and remediation is often directly related to a state’s clean-up standards.

“Many states have adopted risk-based levels for soil and groundwater,” SCRD said. “Alternative evaluation methods that are often considered include presence of receptors, risk pathways, beneficial use of water, current and future land use onsite and on offsite property impacted by the contaminant plume. Groundwater cleanup guidelines varied from the maximum contaminant levels established by the EPA to state calculated or approved risk-based standards.”

Ten of the 28 states have risk-based standards as an option when considering clean-up standards, the report said.

The complete report is available on SCRD’s web site, www.drycleancoalition.org. The site’s Profiles section also has assessment and remediation data for more than 75 drycleaning sites.

SCRD members are state governments that have established programs to fund remediation of drycleaner sites. Current member states include Alabama, Florida, Illinois, Kansas, Minnesota, Missouri, North Carolina, Oregon, South Carolina, Tennessee, Texas, and Wisconsin. California and New York, which do not have formal programs but are active in drycleaner remediation under other authorities, also participate. SCRD operates with support from the U.S. EPA's Office of Superfund Remediation and Technology Innovation and the National Ground Water Association. The next SCRD meeting will be May 12-13 in St. Paul, MN.

The organization’s mission is to provide a forum for states to share programmatic, technical, and environmental information to improve the remediation of drycleaner sites

For information about “Drycleaner Site Assessment & Remediation – A Technology Snapshot (2003),” contact Bob Jurgens of the Kansas Department of Health and Environment, SCRD’s technical issues subgroup chair, via e-mail at bjurgens@kdhe.state.ks.us.

For general information about the State Coalition for Remediation of Drycleaners, contact SCRD Chair William Linn of Florida Department of Environmental Protection, via e-mail at william.linn@dep.state.fl.us.