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News | May 16, 2017

New technologies lead San Pedro DFSP restoration efforts

By Elizabeth Stoeckmann, DLA Energy Public Affairs

A pilot study using new technologies will set the stage for remedial efforts to remove contaminants in the fuel tank farm area at Defense Fuel Support Point San Pedro.

Defense Logistics Agency Installation Support Energy project managers will oversee the testing of two aggressive technologies to clean the soil and groundwater at two tanks: electrical resistance heating and steam injection.

This pilot study will determine how to best implement proven technologies at other tanks in the fuel facility to meet the aggressive schedule at DFSP San Pedro.

“There are two reasons we’re doing this: to promote the cleanup of the site and to facilitate return of the property back to the Navy,” said Carol Heeney, DLA Energy Installation Support project manager.

Both technologies are cost-effective and efficient, and the test will provide the site-specific operational data to implement them, Heeney explained.

Laura Fleming, DLA Energy Installation Support for Energy environmental division chief, explained that the new technologies will take less than two years to remediate the World War II-era site with an overall cost savings of up to $20 million, compared with standard commercial technologies that would take up to 40 years.

“It’s not intrusive, and there should be minimal or no disturbance to the habitat. But we will need to evaluate this before we initiate the pilot test,” Fleming said. “Basically, probes are put in the ground and they are either injected with steam or electricity that ‘cooks’ the soil. The fuel vapors are collected using a vacuum technology to avoid emissions into the air.”

One technology, the ERH, delivers an underground electrical current to an array of metal rods. The heat generated converts groundwater into steam, volatilizing contaminants for extraction. This technology will be used at the site’s Tank 3, located on fine-grained soils and clays. When using ERH, the electrical current is prevented from traveling outside of the treatment area.

ERH is an aggressive remediation technology developed for the U.S. Department of Energy in the early 1990s, that can simultaneously treat the petroleum found in saturated and unsaturated soil, as well as groundwater. ERH is often used to clean sites where other technologies have had limited success, and to remediate quickly and completely.

The second technology uses steam injection coupled with a multiphase extraction of soil vapor and groundwater. By introducing heat below ground around the contamination plume, the fuel contamination is displaced and volatized so that it can be more easily extracted. Steam injection is a very effective removal technique and is well suited for large sites (like Tank 20) with petroleum releases in sandy soils and moderate permeability because heating is strongly controlled by the lateral distribution of steam in the treatment area.

Selecting the most appropriate heating technology is influenced by a specific site’s subsurface permeability, as well as the properties and distribution of the contaminants.

“DLA is completing a large and very complicated remediation at a heavily regulated site,” Heeney said. “All the while, great care is taken to prevent and minimize impacts to the sensitive ecological habitat at DFSP San Pedro.” She noted that because DLA Energy chose to test two tanks in areas with differing geology and physical composition, “The testing will tell us how to apply these two technologies for other tanks in the area.”

Once the contract award is complete pilot testing will take less than 10 months, including equipment installation and the remedial operation.

“We are excited to get the pilot test started so we can meet leadership’s goals and reduce liability to the government,” she said.

Following successful pilot testing, DLA Energy Installation Energy plans to roll out similar cleanup technologies at other tanks in fiscal years 2018-2019 based on funding availability.