HAMPDEN – A plan to temporarily shut down part of Pine Tree Landfill’s gas extraction system was approved Monday by the state Department of Environmental Protection and includes provisions regarding potential odor and safety problems.
Planned for the middle two weeks of July, the shutdown is designed to identify the amount and direction of gases escaping from the conventional landfill, the oldest portion of the facility that was constructed in 1975 under different ownership and less stringent regulation.
The gas extraction system in the newer sections of the landfill will remain on during the testing period.
The shutdown is part of the landfill’s corrective action plan, which includes drilling monitoring wells and installing gas detection equipment on the perimeter of the landfill to track down gases that are escaping from the conventional layer. Once the quantity and direction of the gases are identified, a plan to minimize their escape can be developed, Don Meagher, manager of planning and development for Casella Waste Systems Inc., which owns the landfill, said recently.
“It’s just a piece of data that we need to ultimately determine what the corrective action is,” he said.
Some gases, including odorless methane, have been detected in surrounding soil and groundwater, particularly to the east of the landfill. Gas is extracted from the conventional layer through horizontal trenches at its top, which leaves gases buried deep in the landfill to escape through the soil at the bottom.
Once the conventional layer’s gas extraction system is shut off, officials can monitor how quickly gas pressure builds up, Meagher said.
Though odor and safety problems are not expected to result from the shutdown, the town pushed for stipulations that the system be turned back on under certain conditions, Hampden Town Manager Susan Lessard said recently. One condition is an odor complaint, though it would have to be determined that the odor resulted from the shutdown and rose to a certain level, she said.
“It wouldn’t be an odor related to a load of sludge that just got dumped,” Lessard said.
Odor complaints will be investigated on a round-the-clock basis during the shutdown, and surrounding roads will be monitored for odors, she said.
Turning the system back on, should it be necessary, would be a fairly simple process, Cyndi Darling of the DEP said Monday.
“It’s a matter of turning a valve on,” she said.
If the shutdown goes as expected, the testing period could be extended, Meagher said.
“We don’t want to just arbitrarily shut it off if there’s no reason to and there’s more data to be collected,” he said.