Environment

Navy making good on pledge to clear water of contamination

In this building along Grumman Boulevard, polluted groundwater flowing from the Enterprise Park at Calverton is extracted and treated by air strippers before being discharged back into the ground. (Credit: Tim Gannon)
In this building along Grumman Boulevard, polluted groundwater flowing from the Enterprise Park at Calverton is extracted and treated by air strippers before being discharged back into the ground. (Credit: Tim Gannon)

Because the plume shifts from time to time, the groundwater extraction wells have a capture zone that scientists feel should still be large enough to capture the plume, according to Dave Brayack of Tetra Tech, another consultant on the site.

“There’s always a possibility it could do something we’ve never seen in the past,” Mr. Brayack said. “We’ll keep monitoring it, but the big thing is, if we are continuing to capture mass [VOCs], then we know we are intercepting the plume. The original source area [of pollution] was cleaned up several years ago. We’ve done some calculations that suggested that within several years, there should be nothing more coming down and, at some point, we’ll stop seeing mass. And when we stop seeing mass, we’ll have to make sure the plume hasn’t shifted on us, and if not, at that point we’ll look at shutting [the treatment facility] down.”

Asked by county Legislator Al Krupski (D-Cutchogue) how long it will take to treat all the groundwater “to everyone’s acceptable level,” Mr. Brayack said, “We’ve done the calculations, and the calculations say that’s somewhere between two and four years. But it’s based on assumptions. This system will run as long as it needs to run, so two to four years is really the minimum.”

After the meeting, Mr. Krupski said, “I’ve got a pretty good background in soils and soil chemistry, so I understand what they are talking about, and I’m pretty impressed with the way they’re doing the operation. It seems like their treatment methods are effective. It’s just a matter of them finishing the job.”

The Navy’s tests also indicate that the plume has not traveled under the Peconic River, Mr. Brayack said. When news of the plume first broke five years ago, there was concern that if contaminants ran deep enough in local groundwater, they could flow under the river into neighborhoods farther south.

The primary contaminants in the plume come from jet fuel and chlorinated solvents that were dumped on the land when Grumman operated there from 1954 to 1995, according to James Tarr of the Naval Facilities Engineering Command, which is leading the cleanup.

“This is where they pressure tested the fuel lines on the aircraft, and they leaked,” Mr. Tarr said last week.

“Petroleum constituents usually don’t make it too far” from where they’re spilled, he said. “But chlorinated solvents have a tendency to run with the groundwater, and they don’t degrade very well.”

The Navy, which turned over most of the former Grumman land to Riverhead Town in 1998, retained ownership of four properties there where cleanup was required due to contamination from the Grumman days.

In 2007, the Navy turned one of those properties, a 144-acre site that had been deemed clean, over to the town. The three remaining parcels the Navy owns at EPCAL are 169 acres adjacent to land sold by the town to developer Jan Burman, 30 acres on the southern boundary near Grumman Boulevard/River Road and nine acres surrounded by Mr. Burman’s property.

In addition to the plume that’s traveled off site, the Navy is cleaning three other sites at EPCAL, including an old munitions dump on the southwest portion of the property, where soil excavation is expected to start in May.

Also being cleaned is an old fuel depot site within Mr. Burman’s acreage. This site has been treated since 2005 by an “air sparging” system and soil vapor extraction. But that system, which had been operating seasonally, may be near the end of its functional life, according to Mr. Brayack, because the blower burned out and will need a major overhaul to get it working again. That system, he said, was designed for four years of use and has been in operation for close to eight.

There are a number of test wells in the area to measure the amount of contaminants in the groundwater there, he said.

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