Since June, an extraction well off the base has pumped 16 million gallons of EDB-contaminated water to a temporary treatment facility on base where it has been cleaned to drinkable standards.
BY DENNIS DOMRZALSKI
Adria Bodour has four words to describe the U.S. Air Force’s plan to clean up the Kirtland Air Force Base Fuel Spill: no carbon left behind.
Although it will take at least a decade to clean up the underground plume of aviation gas-polluted water, the Air Force said none of the contaminates will reach city drinking water wells, Bodour and others involved in the cleanup effort said Tuesday night during an update on the cleanup effort.
The goal of the cleanup plan is to “leave no LNAPL [light non-aqueos phase liquid, or aviation fuel] behind, no carbon left behind,” Bodour, the Air Force’s chief technical expert for the spill, said during a public meeting at the state fairgrounds.
As he has done in the past, Dennis McQuillan, the New Mexico Environment Department’s lead scientist on the spill, assured the audience that the plume of gas and dissolved ethylene dibromide [EDB] won’t reach nearby city wells. “It is a big plume, but it is not going to engulf the entire Northeast Heights or migrate to the Westside,” McQuillan said.
Bodour and NMED officials detailed the progress that has been made in the effort to clean up the estimated 6 million to 24 million gallons of aviation fuel that leaked into the aquifer from an underground pipe at Kirtland’s Bulk Fuels Facility over what could have been a period of 40 years. They also described what will be happening in the coming months to accelerate the clean up.
Here’s a summary of the efforts so far:
Since June, an extraction well off the base has pumped 16 million gallons of EDB-contaminated water to a temporary treatment facility on base where it has been cleaned to drinkable standards. That water has been used to irrigate the base’s golf course.
Two more extraction wells have been drilled and will begin pumping polluted water in December or early January. Those wells can extract between 150 to 200 gallons of water per minute. One well is at the northern tip of the 6,500-foot-long EDB plume, while the other is near the middle and across from the first extraction well that began pumping in June. The idea is to cut the plume in half and create the “hydraulic equivalent of a firebreak” to prevent it from reaching city wells, McQuillan said.
A full-scale treatment facility on base in nearing completion and will be operational in December. It contains two 20,000-pound vessels of granulated activated carbon through which the contaminated water will be run and cleaned. The facility is designed to clean around 1.5 million gallons of water a day, which would be eight extraction wells pumping 100 gallons a minute.
Three pilot projects to store and clean water will begin in December and early spring. The first is an effort to examine the feasibility of injecting the cleaned water back into the aquifer. It will use an existing well on base that was once used to pump water to irrigate the golf course. The filtered water will basically be poured down the well shaft where gravity will pull it into the aquifer. The second is a bioventing test to see if bugs—microorganisms—in the ground that are already eating the trapped aviation fuel, can be encouraged to eat more of it. The process involves pumping air 200 feet into the ground to give the microorganisms a healthier environment. The third is an anaerobic biodegradation test that will feed nutrients to underground microorganisms that are eating the EDB in the hopes that they will eat greater quantities of the contaminant.
Later this year, the NMED will release its strategic plan and goals for 2016. The plan will be an outline, and not a regulatory document. But it will guide the Air Force and has consequences if its goals are not met, McQuillan said.
The Air Force has removed 4,822 tons of contaminated soil from the spill site itself.
Here are some takeaways from the meeting:
Microorganisms are actually eating some of the aviation fuel that remains trapped in the ground above the water table. Bodour estimates that those bugs have eaten more than 200,000 gallons of the fuel.
How the fuel leaked is a fascinating story. It seeped from three thumb-sized holes in an 16-inch diameter pipe that was buried 18 feet in the ground. But it didn’t leak continuously. The pipe transferred fuel from railroad cars and tanker trucks at an unloading dock to a pump house, and then into above-ground storage tanks. A vacuum was applied to the pipe during the unloading and transferring process. It was only when the vacuum was turned off and the transfer process stopped that the residual fuel left in the pipe leaked out through the three holes.
It’s nearly impossible to determine how much fuel spilled, and no one knows for sure how much escaped. Why? Because there was no metering in those days and because the leaks weren’t constant. And tracking down 40-year-old logs from the fuel-transfer process is nearly impossible. The BFF was built in 1951 and became operational in 1953. No one knows when the leaks began. The spill was discovered in 1999. Bodour said she has tried to calculate the amount of fuel spilled, but just can’t.
There is no aviation fuel or EDB in the water table [500 feet down] directly under where the spill occurred, and that’s what confused scientists in 1999 when the spill was discovered. Here’s why: Because of the underground geology of the area, the fuel sort of slid away from the site to the northeast, meaning it didn’t seep straight down into the aquifer. The area is layered with high permeability and low permeability regions of sand and rock. The fuel leaked into high permeability areas, but couldn’t migrate down further because it was blocked by low permeability layers. So is slid to the northeast and away from the pipe until it found a gap in the low permeability layer and oozed down into another high permeability layer. It migrated downwards in that stair-step fashion, until it slid away from the actual leak site, and eventually into the aquifer. When researchers first drilled wells to see if the fuel had hit the aquifer, they drilled right near the leak site. The first four wells they drilled showed no groundwater contamination. It was only with the fifth well, which was much further from the leak site, that they found fuel in the aquifer.
Once more extraction wells come on line, the parties will have to figure out what to do with all that water. Although it is cleaned to drinking water standards, the Albuquerque Bernalillo County Water Utility Authority won’t allow it to be put into the drinking water system. The golf course on base can take only so much before it turns into a lake, and it really can’t be watered in the winter. That’s why officials are looking at getting the water back into the aquifer either through infiltration galleries or injection projects.
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