Yesterday, Steve Harwood, the operations director at the plant, said samples of the waste have been sent to a microbiology lab in California in an effort to determine the cause of the overflows. In the meantime, Harwood said a defoaming agent is being pumped into the tanks, but the overflows are continuing.
“One of them stopped foaming, one’s foaming just a little bit and one’s still going pretty good,” he said.
During a visit to the site yesterday afternoon, none of the tanks was foaming. Heaps of clay were packed between and around the barriers to block the sewage from seeping through. Little of the thick, lumpy waste remained outside the barriers, although there were deep piles of it inside the barriers and on the circular stairways to the tops of the tanks.
Harwood said the overflows are impossible to predict and difficult to prepare for. He defended the cleanup effort, which he said included spreading 600 pounds of lime on the grassy areas around the tanks, and said crews were issued protective gear.
“We had pumps,” he said. “They blew up.”
“I don’t know if there’s anyway to prepare for this,” he said. “It just happens. The (barriers) have been in place. Everyone’s got protective gear that they can wear. They’ve got face masks, rubber boots, rubber gloves, Tyvek suits. It’s 95 degrees out there and humid. They dehydrate in those things. If they don’t wear them, that’s their option.”
Harwood estimated that the spills have amounted to thousands of gallons so far, but said he could not be more specific.
The plant serves Lawrence, the Andovers, Methuen and Salem, N.H.