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The Best Soil Remediation Tools Available

Oct 2, 2018Architecture, Engineering, Environmental, Mining, Oil & Gas

Aerial view the junkyard site at Wrangell taken August 19 that shows two-thirds of the stockpile of treated soil has been removed; the removed soil was transported to an Oregon landfill.


Judy Mottl

Of about 7,600 contaminated sites in Alaska, some 70 percent have been cleaned up with 2,300 remaining that require additional remediation.

Prevention, awareness, and innovation

Of about 7,600 contaminated sites in Alaska, some 70 percent have been cleaned up with 2,300 remaining that require additional remediation.

The bulk of those sites, about 73 percent, are contaminated by petroleum, the most common toxic matter when it comes to land-based spills statewide, according to Alaska Department of Environmental Conservation (DEC) officials and remediation specialists.

“We are in a much better place [with regard to land-base spills] than we were back in March 1989,” says Graham Wood, program manager of the DEC’s Prevention Preparedness and Response Program, which was launched following the Valdez oil spill in 1989.

“The state was in a position where it thought it had things under control [in terms of spill response and prevention] and it clearly didn’t. So out of that came what we have today with our response regulations,” he says. “We’ve been making steady progress in the world of prevention.”

His view is echoed by environmental geologist Tim Shaw, who works for Environmental Contracting Solutions (ECS), a Kodiak-based company that provides an array of remediation-related services including site investigation, spill response, and soil remediation.

“Having been in the environmental services and consulting field for over twenty-seven years, I have seen an increase in prevention plans, strategies, and contingencies for spills,” says Shaw.

“In my opinion, much of this is self-induced by the companies to lower their risks. There is sufficient history now that most companies have seen what the high financial costs and long-term environmental impacts can be from poor environmental controls. Also, the older generation which did things the old way have retired or passed on. The newer generations are more environmentally savvy.”

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Overview of the staging area and barge loading site in Wrangell for hauling the bagged, treated soil off-island.

Spill Prevention, Quick Response

Some of that savviness may be the result of state outreach and education efforts to teach companies how to prevent land-based spills. Program leaders meet with businesses and communities about prevention strategies, as well as federal agency counterparts to talk about spill reporting notification requirement and basic prevention actions, such as a tank farm having transfer procedures in place, an incident plan on hand, and remaining onsite during a transfer activity.

DEC encourages new businesses dealing with oil, gas, and chemicals to communicate with the organization about remediation plans and prevention strategies.

“We’re always happy to talk to companies about how best to prevent potential spills. It’s free advice. When you spill oil, it’s not free advice.”

Once notified of a spill, Wood’s program serves in an oversight capacity regarding cleanup and remediation, working with the responsible party.

“We are not in the response business; we are in the oversight business, and our interest is in making sure contamination is remediated immediately or as soon as possible,” he explains.

Traditional Remediation Strategies

The strategy for remediating land-based spills is tied to three elements: time, cost, and space, says ECS’s Shaw, and traditional approaches involving manual labor and shovels are still prevalent.

“After the 1988 Exxon Valdez spill there was an explosion in remediation methods, ideas, and tools. But the preferred method remains to be removal of contaminated materials; however, that is not always a possibility due to excessive costs, accessibility, or the fact that more damage to the environment will be done through removal than leaving soil in place,” he explains.

Cost is a major factor when it comes to soil remediation. Shaw says he’s seen removal costs in remote sites reach in excess of $2,000 per cubic yard—about ten times that of a remediation effort located along a road system.

Today’s in situ remediation systems have matured, and basic methods remain the same—moving air in and out of soil to enhance naturally occurring microbes and to remove volatile vapors.

Ex-situ remediation can include soil removal and thermal desorption (burning contaminated dirt), land filling, or land farming.

Land farming is when a shallow layer of contaminated dirt is placed within a lined, protected “cell” that can be covered to keep water out but allows a rototiller into the cell to till and aerate the soil. This takes space and time but minimizes costs, notes Shaw.

No one remediation approach is cheaper or easier than any other as each spill presents its own challenges. A remediation strategy “depends on the situation,” notes Wood, and costs can run high. For example, when burning soil there are labor, equipment, and transport costs that arise from taking the soil from the contaminated site to a facility and then back to the site as clean fill.

Long-Term Remediation

When a land-based spill can’t be remediated in a short time to meet state acceptable levels, the DEC’s Contaminated Sites division steps into action.

“We deal with the longer term cleanups,” explains John Halverson, the agency’s contaminated sites program manager.

In many instances contaminated soil and water monitoring is set up to determine the full impact of the spill and best cleanup approach. DEC works with the responsible party, providing oversight and approving the remediation plan. Soil remediation on large sites often requires excavating soil and transporting to a private treatment facility for thermal treatment.

One such facility is Alaska Soil Recycling, a subsidiary of Anchorage Sand & Gravel (AS&G), which was the first state-approved, off-site treatment facility to offer thermal desorption. The facility can store up to 30,000 tons of soil for treatment, according to Brad Quade, Alaska soil recycling manager for AS&G.

Land farming is a common alternative, but the slow natural attenuation of contaminates (because of Alaska’s climate) typically requires more resources and much more time, says Quade. A remediation approach is often determined by spill location and size.

“With many of the remote sites, there is a lack of infrastructure and equipment to do things easily on site,” he says.

Alaska state regulations require that any release of oil to land in excess of 55 gallons be reported as soon as a person has knowledge of the discharge; any release in excess of 10 gallons but less than 55 must be reported within forty-eight hours.

While the majority of spills involve a responsible party, a remediation effort can also be initiated by the state. In that scenario DEC is not only is the overseer but serves as the remediation project manager.

Remediation costs for a former junkyard in Wrangell hit more than $6 million.

Byford Junkyard

DEC served the as remediation lead for the cleanup of the former Byford Junkyard in Wrangell. The site housed large piles of metal and improperly stored hazardous materials, from batteries and tanks to drums and tires.

An assessment revealed extremely high levels of contamination, including elevated levels of lead, and the federal government deemed the site an imminent risk to human health and the environment.

In 2014 DEC approved a $3.9 million spending plan to perform an emergency cleanup with a DEC contractor. While no new contaminants were found, the volume of material requiring treatment was much greater than the original assessment estimate, which boosted cleanup costs to $6.5 million.

The original plan was to remove soil and transport it to a hazardous waste facility in Oregon. But the escalated costs led the state to devise a new plan to treat and store the soil onsite. But that plan was then altered because of the cost associated with building a facility to house the soil.

The final solution is to treat soil onsite with Ecobond, a compound that reduces solubility of lead, and then dispose of 18,500 cubic yards of soil at the Columbia Ridge Landfill in Arlington, Oregon. The soil being shipped out is loaded into flexible intermodal bulk containers for transport, and as of mid-August, one barge of soil had left Alaska “with a few more barges to go,” Halverson reports. DEC anticipates site restoration work will be completed and the remaining soil will be off-island by mid-October.

A barge load of flexible intermodal bulk containers leaves Wrangell on August 7, headed to Columbia Ridge Landfill in Arlington, Oregon.

On the Horizon

While various soil remediation approaches are in play, some new technology and tools are in use and on the horizon.

Discovery Drilling, a geotechnical and environmental drilling services company based in Anchorage, is using an optical image profiler (OIP) geoprobe for identifying and monitoring certain contaminates in a quicker, easier, and more cost-effective fashion.

The device features a camera and uses UV light to locate gas, diesel, or motor oil in real time.

“Before, if we wanted to drill and do a soil sample, it was a long process: you take a sample, send it to the lab, and then wait for results. Sometimes a sample would show nothing [and] then you would have to take more samples. With this [OIP] we know right away what’s there,” says Keeter Brown, Discovery Drilling vice president.

Environmental engineering firms often engage Discovery Drilling to investigate the extent of a spill and provide soil sampling and groundwater testing services.

The geoprobe is one of several new technologies that was presented by Discovery Drilling during a recent brown-bag workshop with DEC officials. Others include hydraulic conductivity and electromagnet conductivity.

The OIP, says Brown, presents a compelling option given its capabilities and time savings.

“The OIP, in the right conditions, can get spill delineation and site characterization results at up to three times the rate of traditional soil sampling. It doesn’t take the place of traditional soil sampling methods but can definitely reduce the amount of sampling required.”

As the industry strives to reduce costs and manpower involved in spill remediation, innovative spill prevention and remediation options will continue to evolve, says ECS’s Shaw. “As long as people keep using their imagination there will be new remediation tools, some worthy of use, others not much more than a get rich quick idea,” he says, adding: “The best remediation tool will always be prevention.”

“Developing new areas for mining, drilling, and industry in keeping Alaska strong can be accomplished safely and effectively within the existing regulations as long as the attitude of the management of those developers have the knowledge, respect, awareness, and understanding of the short and long term effects of environmental impacts,” he says.

“The human factor means that spills will occur, but environmental professionals like myself are there to respond to spills, minimize further environmental impact, and restore the contaminated area as close to original as practical.”

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