BANGOR – Five University of Maine students, upset about air emissions from the biomass boiler in Old Town slated to be operated by Red Shield Environmental LLC, the company purchasing the former Georgia-Pacific Corp. mill, protested Thursday at the local Maine Department of Environmental Protection office.
The group, carrying cardboard signs protesting the burning of construction and demolition debris, which they say would release contaminated materials into the air, submitted letters to the DEP asking for a public hearing.
DEP Bureau of Air Quality officials responded Thursday by stating the students do not have all the facts.
The DEP is in the process of reviewing Red Shield’s request to transfer licenses to operate the facility, including one to operate the biomass boiler.
“I think people have a very dangerous misconception about what this is all about,” William Mathewson, a UM philosophy student, said while holding approximately 10 letters that ask for a public hearing.
Thursday was the deadline to submit comments concerning Red Shield’s licensing.
The students did not attend the public meeting about the issue held Wednesday in Orono and did not protest when G-P originally applied for licenses to operate the biomass boiler, they acknowledged.
Phillip Kohler-Busch, a UM student who lives in Bangor, explained that construction and demolition debris is typically contaminated.
“What’s in that waste shouldn’t be in the air,” he said. “I live in Bangor, but I do hunt mushrooms in the Old Town area, and mushrooms do soak up what’s in the air.”
Jim Brooks, DEP Bureau of Air Quality director, said it’s true that construction and demolition debris contains contaminants, but he added that all biomass boilers have control systems in place to severely reduce emissions. The state also recently established standards concerning the burning of construction and demolition debris.
“The materials will contain [a] small amount of contaminants,” he said. “Basically any wood materials contain a small amount of contaminants.”
Biomass boilers have two systems to control the fine particles created when items are burned.
“They have a multiclone and an electrostatic precipitator,” Brooks said. “I believe the efficiency is like 99.99 percent.”
An electrostatic precipitator is a large box that has high-voltage electrodes inside which give a negative charge to dust particles in the exiting smoke, which then are attracted to a grounded collecting surface that is positively charged. The multiclone is a dust collector that uses centrifugal force to separate dust particles from the discharging smoke before leaving the stack.
The heat level of the combustion itself is another tool that can be used to regulate emissions, Brooks said.
“The G-P boiler in Old Town was licensed to burn construction and demolition debris but never burned it,” Brooks said. “[Red Shield] has asked for an exemption for the carbon monoxide emission rate for a period of nine months.”
Red Shield has not asked for a substandard license, he said, which is a claim made by the protesting students.
The Legislature enacted a new rule last year that limits the amount of construction and demolition debris that can be used to less than 50 percent, Brooks added.
“It’s a fairly tight standard,” Brooks said. “It’s the only standard in the U.S.”
Tamarack Energy, a renewable-energy developer, plans to restart G-P’s biomass boiler system, fueling it with a combination of wood chips and clean construction debris, and is limiting the amount of debris to less than 33 percent.