NORTH ANDOVER — An exchange of e-mails between state environmental officials and the operators of the region’s sewage plant suggests the operators were ill-prepared for the overflows at three treatment tanks that began July 1 and continued yesterday, even though the overflows occurred several times before.
Two of the plant’s 40-year-old portable pumps that would have been used to suck up the noxious mix of human industrial wastes broke down at the start of the clean-up, the emails disclose. There was a shortage of hoses, although that may not have mattered with too few working pumps. The two-foot concrete containment barriers that were installed around the tanks during earlier overflows were unevenly spaced and too short, allowing partially treated sewage to push under and around them — and sometimes over their tops — and to spill across a service road and into an adjoining wetland.
The e-mails add to the impression of the cleanup during several visits by The Eagle-Tribune during the week of July 8, when the battle to contain the sludge was being waged by crews armed with little more than garden hoses and squeegees and wearing little or no protective gear or clothing. A vacuum truck capable of holding 2,500 gallons stood by.
Last week, the state Department of Environmental Protection said the Greater Lawrence Sanitary District “violated, and continues to violate” the state Clean Waters Act “by allowing the discharge of partially treated sanitary sewerage to ground waters of the Commonwealth without a valid permit.”
The charge, contained in a “Unilateral Administrative Order” dated July 16, also directed the sanitary district to “take any and all actions” to contain the overflows within the concrete barriers and to cleanup the sewage that pushed past the barriers by July 19.
The order, signed by Eric Worrall, the acting director of the DEP’s Northeast Regional Office, also ordered the district to spread lime on the grassy areas surrounding the 40-foot treatment tanks (15 feet are underground) and to provide the DEP with daily updates on the cleanup.
In an separate directive, the agency also ordered the sanitary district to pack the spaces between the barriers with clay.
The order also cited an anonymous allegation that some of the overflowing sewage had reached the Merrimack River a few hundred yards to the west, which plant operators have denied. Worrall said the allegation was relayed to the DEC by a North Andover conservation official, who told the DEP she received “complaints of a sludge/sewage discharge to the Merrimack River via a wetlands/stream area emanating from the facility.”
Jennifer Hughes, North Andover’s conservation administrator, could not be reached yesterday.
Susan Sawyer, the director of the town’s Health Department, said the department has not had an active role in the cleanup because the treatment plant is in an isolated and buffered corner of the town and the spills are not a threat to residents. The plant is off Charles Street, between the runways of the Lawrence Municipal Airport on the north, east and south and the Merrimack River on the west.
“The people it’s affecting most are the people working with it,” Sawyer said. “The citizens aren’t at any risk. We’re counting on the DEP.”
The waste inside each of the 1.4 million-gallon tanks is in an early stage of treatment and still contains coliform bacteria and other pathogens that can cause a range of diseases, including hepatitis A, typhoid and salmonellosis.
Richard Hogan, the executive director of the sanitary district, said earlier this month that the cause of the viscous, black waterfalls pouring from the tops of the tanks is uncertain and said there is no known fix except to allow it to run its course. He said other overflows have occurred before, most recently about two years ago.
The overflows are not unusual in treatment tanks with similar designs nationwide, which have unsealed caps that float on top of the gases inside.
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.