HAMPDEN – State environmental officials said this week they expect to grant the Pine Tree Landfill a new air emissions license, required as part of the landfill’s expansion plans.

The licensing by the Maine Department of Environmental Protection should occur within the next few weeks, according to a DEP official who said federal authorities had recommended minor wording changes to the document before it is approved.

The emissions license is required when a landfill’s approved capacity exceeds 2.5 million cubic yards.

The Hampden landfill was granted permission to expand to up to 3.8 million cubic yards, although Tom Gilbert, environmental manager with Pine Tree, said the landfill had reached only half that level.

Lynn Ross, environmental engineer with the DEP, said the license covers only air emissions because the agency doesn’t have authority over water, noise or odor issues.

The Hampden landfill is permitted to release up to 20 metric tons of nonmethane organic compounds a year.

Through a flare-burning process, only about 1/4-ton is released, according to landfill officials. The federal government doesn’t require such a burning system until emissions reach about 45 metric tons.

Pine Tree, operated by Casella Waste Systems Inc., is installing thousands of feet of piping to carry gas developing inside the landfill mounds to the flare.

By the end of next year, landfill officials expect to have a generator system in place that will turn the gas emissions into electricity that could be used in-house or sold.