BANGOR, Maine — Three windmills recently installed at Bangor International Airport are the latest in a series of steps the city has taken to improve the water quality of Birch Stream.
Located off Godfrey Boulevard, the windmills power an air compressor that blows air into runoff stored in an underground basin, John Murphy, assistant city engineer, said this week.
Murphy said the runoff needs to be aerated because it contains de-icer fluid, which depletes the water’s oxygen supply as it decomposes.
“What the windmills are trying to do is put some oxygen back into the water,” he said.
The windmill project is among several the city has conducted with $2.8 million it received this spring under the American Recovery and Reinvestment Act, also known as President Barack Obama’s stimulus package, he said.
Other work included improvements to Godfrey Boulevard, the reconstruction of a retention pond and channel also at BIA, and improvements to the Penjajawoc Stream watershed near the Bangor Mall, Murphy said.
The city also used some of the stimulus money to buy in-stream monitoring equipment and a high-efficiency street sweeper designed to reduce the amount of debris that eventually could wind up in streams.
Birch and Penjajawoc streams are among five waterways in Bangor that have been deemed impaired, or polluted, by the Maine Department of Environmental Protection. The others are Shaw Brook near Birch Street, Arctic Brook along Valley Avenue and Pushaw Stream near the Glenburn town line.
The watershed improvement projects aim to substantially decrease nonpoint-source pollution, City Manager Edward Barrett said in March, when the city announced its intent to accept the federal stimulus money.
Birch Stream first came under scrutiny in 2003, when officials from the Maine Department of Environmental Protection began investigating contamination of the stream by a de-icing agent the airport was using on military and commercial aircraft.
Some residents of the nearby Griffin Park housing complex complained that the propylene glycol antifreeze used in the de-icer caused headaches and other ailments, although there were no scientific data to support those claims.
The DEP, however, did determine that Birch Stream was heavily polluted, though it also concluded that runoff from the airport and the nearby Maine Air National Guard base was only part of the problem.
The waterway runs underneath a dense commercial district along Union Street, including the Airport Mall.
The city and airport have been working with the Air Guard and numerous other stakeholders to implement a comprehensive watershed management plan designed to improve water quality in Birch Stream.
BIA and the Air Guard recently installed a de-icer collection system, which diverts the fluid from the stream to the city’s wastewater treatment facility. They also have teamed up to clean debris from some sections of the stream.