Steve Harwood, operations director at the treatment plant, notified the DEP about the overflows on July 2 in an email that now appears to have been overly optimistic.
“We have the foam contained with jersey barriers,” Harwood said in his email to Mohatny Nihar, a DEP engineer. “As of now the foam has subsided on 2 of the 3 digesters and slowing down on the 3rd.”
Things apparently worsened as the week went on.
Three days later, aerial photographs showed wide streams of the sludge running past the containment barriers, pooling on the service road that loops past the tanks and flowing into the adjoining wetlands and the two storm drains that serve the area. A warning posted in a sludge-saturated stretch of the wetlands warns, “Protected wetlands. Restricted access.”
On Tuesday, at least two of the three tanks were gushing sludge, streaking the concrete sides of the tanks with black slime and fouling the circular aluminum stairways that run up along the outside.
On Thursday, one tank was bubbling over. On Friday, two were.
On Thursday, nearly two weeks after the spills began, the chairman of the sewer district’s board of directors said he had not been to the site.
“From what I understand, sometime this week they put plywood between the barriers to try to prevent it from leaking through,” Chairman Thomas Connors said. “I know they’re pumping it back into the tanks. They have a (pumper) truck to pick up anything that seeps through. Beyond that, I don’t know what else we can possibly do.”
The wetlands that circle the treatment complex and separate it from the airport runways and the rail tracks and river are regulated at least in part by the North Andover Conservation Commission. Hogan said Jennifer Hughes, the town’s conservation administrator, visited the plant after the spills began.