ITRC Helps Air Force Cut Costs With Passive SamplingITRC Helps Air Force Cut Costs With Passive Sampling

www.itrcweb.org ■ email: itrc@itrcweb.org ■ July 2014

Many manufacturing plants of the mid-20th century, operating under less stringent environmental

regulations and without today’s knowledge and technology, eventually found themselves facing the cleanup of soil and groundwater contaminated by chemicals after decades of use. Environmental cleanups are by nature time consuming, complex, and expensive. The technically sound, innovative solutions provided in guidance documents and training courses supplied by the Interstate Technology and Regulatory Council (ITRC) have resolved challenges at contaminated sites, saving thousands of dollars during the cleanup process.

The Issue – High Monitoring CostsThis was the case with the United States Air Force Plant (AFP) 44 in Tucson, Arizona, where passive sampling was adopted to save time and thousands of dollars in monitoring costs. At AFP 44, contaminants associated with manufacturing processes were discovered in soil and groundwater. The contaminants identified at AFP 44 included chlorinated solvents, 1,4 dioxane, and chromium. The site entered into the Superfund program in the 1980s and remediation

began. Over 300 groundwater sampling wells were installed, with frequent sampling to monitor the cleanup progress occuring at nearly half.

Bill DiGuiseppi, a senior hydrogeologist who worked on the site remediation, explained that “frequent sampling of many deep and high volume-producing wells was resulting in a very high cost of monitoring for the U.S. Air Force.” After remediation began in the 1980s, dedicated pumps were installed for monitoring at several wells. The sampling process produces “purge water,” extra water that is pumped out of the well to flush it and which must often be treated or disposed of as hazardous waste.

More than a decade later, the pumps began to fail. With replacement costs estimated at $3,000 to $4,000 per well, portable pumps powered by an external generator were used instead for the approximately 100 wells with failing pumps. Although these pumps got the job done, they also significantly increased the time and costs associated with monitoring deep wells and produced hundreds of gallons of purge water that had to be transferred to an onsite plant for treatment. Because the wells were 150 to 300 feet deep and the portable pumps required decontamination between wells, the time required for sampling was high.

ITRC’s guidance documents and training course helped the U.S. Air Force implement passive sampling at AFP 44, saving an estimated $30,000 per year in monitoring costs.

▪ Decreases Sampling Costs▪ Saves Sampling Time▪ Lessens Sampling Effort▪ Eliminates Purge Water▪ Produces Representative Samples▪ Reduces Sampling Variability▪ Deployable over a Wide-Range of Conditions

Benefits of Passive Sampling

DEPLOYING A PASSIVE SAMPLER

Prepare Bag and Place in WellDetermine Deployment Depth

Pull Out Bag Filled with SampleFinish Deployment, Wait for Equilibration

Tap Bag with Sample Straw and Fill Sample Bottles

Use Remaining Water to Measure other Parameters

www.itrcweb.org ■ email: itrc@itrcweb.org ■ July 2014

The Solution – Passive Sampling Passive sampling was identified as one of several potential optimization methods to reduce groundwater sampling costs. Passive sampling allows a sample to be collected from a discrete location or interval in a well, without the active water flow associated with a pump and purge technique.

However, because passive sampling was such a new technology, many people were not familiar with it or how to implement it. ITRC was one of the first organizations to embrace the new and more efficient technology and offered guidance and training on the topic.

U.S. Air Force remedial site manager, George Warner, explains that ITRC “gave credibility to the process.”

After reading a U.S. Army Corps of Engineers study and attending an ITRC training course, DiGuiseppi invited regulators and scientists involved in the cleanup to learn more about the new cost-saving technology. The U.S. Air Force then conducted a pilot study to compare the pump sampling approach to passive sampling and concluded that the resulting concentration numbers matched. Regulatory approval was also needed before passive sampling could be used. Using the ITRC guidance as a reference helped the U.S. Air Force receive regulatory approval from U.S. EPA and the Arizona Department of Environmental Quality for the change to passive sampling.

“The key to success was having an impartial third-party technical group [ITRC] talking about the technology,” said DiGuiseppi. “Ultimately, we have achieved regulatory acceptance of using passive samplers for most of our sampling, resulting in tens of thousands of dollars per event in cost saving, primarily due to significant time savings for the field crew,” he concluded.

According to Warner, the numbers generated with passive sampling have been consistent from year to year, especially as the process is refined and sampling technicians became more familiar with the equipment. The passive samplers have worked so well that the U.S. Air Force plans to use them for all future monitoring wells at the site.

Benefits of Passive SamplingPassive sampling allows for measurement of all contaminants of concern in the same collection device and eliminates production and disposal of purge water, while saving substantial time and money. Warner also describes passive sampling as “green,” explaining that it not only eliminates the purge water, but also the requirement for a vehicle to transport it from the isolated monitoring wells for disposal.

The U.S. Air Force presently saves about $30,000 per year in monitoring costs using passive sampling at 50 wells. The technique also reduces sampling time at each well by approximately two hours, making it a more efficient method.

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To learn more about passive sampling and to access other ITRC resources, visit www.itrcweb.org. All ITRC guidance documents and training

courses are available for free on the ITRC website.