That sulfurous asphalt smell that drifts across the Mississippi River into the Bottineau and Marshall Terrace neighborhoods may go away in a few months.
Shingle manufacturer GAF announced recently that it has committed to purchasing a $4 million regenerative thermal oxidizer (RTO) and will install it at its plant at 50 Lowry Avenue N. Plant Manager Aric Arneson said the RTO will be built specifically for GAF and will be operational in 12-18 months. Installation will begin in 2019.
Fourth Ward City Council Member Phillipe Cunningham welcomed the news in a statement, “When I was elected to office, I was concerned about the long-term impact of GAF staying in place from an environmental equity lens and from a public health perspective. The smell from the plant has long been an issue in the community. Neighborhood associations as well as residents of Wards 1, 3, and 4 have banded together asking for environmental justice. The news of GAF installing a RTO in an effort to be a good neighbor in our community is very exciting!”
Cunningham said he and his office staff “did a deep dive” into the issue and sought to have an RTO installed as part of a condition to allow GAF to continue to store its finished products on a city-owned lot next to the plant. When his “community benefits agreement” did not meet with support from the community or the Upper Harbor Terminal development team, he said he directed city staff to not renew GAF’s lease on the lot. Arneson said GAF now stores its shingles in Shakopee and Savage before exporting them to Canada and the domestic market.
In 2014, GAF spent $500,000 on upgrading fans, and adding automatic damper controls and an oxygen sensor to mitigate the odor. Arneson said the RTO is part of planned investment in the GAF plant. “We see this as a great opportunity to improve our environmental footprint,” he said. “It’s a somewhat duplicative effort, but it’s our intent to be a good community member.”
The Bottineau Neighborhood Association (BNA) responded swiftly to the GAF announcement. In a letter to elected officials, BNA President Mariam Slayhi asked, “Putting in an oxidizer will improve shingle production but will it fix the air pollution problem caused by the asphalt smelting? Does an oxidizer or other air cleaning device exist for asphalt smelters/heaters? Can GAF show us the device they will use to clean up the used asphalt smelting process?” She asked for assistance in asking the Minnesota Pollution Control Agency (MPCA) to do a full permit review of GAF before allowing installation of the RTO.
Third Ward City Council Member Steve Fletcher said in an email, “I’ve heard from many constituents that they would strongly prefer GAF cease operating in the neighborhood. It’s not clear we have a path to making that happen, so I agree with our Department of Health staff that the next best alternative is to make GAF’s operation cleaner, safer, and less of a nuisance.”
How an RTO works
Sarah Kilgriff, manager of the land and air compliance section of the MPCA, said, “The RTO is really the gold standard in emission control equipment. It’s very efficient; 95 to 99 percent of pollutants are destroyed. These devices have been long known to reduce odors as well.”
She said RTOs have been used by ethanol and paint manufacturing plants, printing companies, pharmaceutical companies and automotive and semiconductor manufacturers. They remove volatile organic compounds (VOCs), hazardous air pollutants (HAPs), industrial odors, organic solvents, emissions, greenhouse gases and other pollutants.
Cunningham agreed. “RTOs are currently the top go-to technology for lowering odor and VOC emissions. Negotiating a RTO was also supported by Midwest office staff of the Federal Environmental Protection Agency who contacted me after Northeast residents reached out to them asking for help with GAF.”
A regenerative thermal oxidizer is basically a giant heat exchanger that operates at very high temperatures, 1300-1500 degrees F. (Asphalt melts at around 410 degrees F.) Polluted air enters an energy recovery canister, where it’s pushed into a combustion chamber that’s lined with ceramic media. A natural gas burner heats the polluted air to about 1450 degrees and keeps it at high heat until it turns into carbon dioxide and water vapor. The “burned” air goes through a second chamber, where the heat is recovered. The heat can be re-used to heat more polluted air; sometimes it’s hot enough that the natural gas burner does not re-ignite, which reduces the manufacturer’s energy costs. The cooled clean air is sent out of the plant’s chimney and into the atmosphere.
So what will come out of GAF’s stack? “Heat and water vapor,” said Arneson. “This is really another layer of technology,” he said.
Ralph Pribble of the MPCA Public Information office said, “GAF reports around 5 tons per year of VOCs (volatile organic compounds) in our Emissions Inventory, so assuming 95 percent destruction from the new equipment, it would be reasonable to expect they will go to emitting only about 1/4 ton of VOCs. That would be a significant reduction.”
Fletcher said, “I’m encouraged that they’re pledging to take some fairly aggressive steps to improve their operations, and significantly reduce the pollution and odor resulting from their operation.”
Arneson says GAF has a stake in North Minneapolis. “We’ve been here since 1938,” he said. “We provide 100 jobs in North Minneapolis. We serve developers all over the Twin Cities. We’re involved in the STEM and STEAM programs at Patrick Henry and North High School. And we do business with our neighbors at North Market. We try to spend our dollars where we operate. We don’t go to Starbucks for coffee; we go to the local coffee shop.”
Kevin Reich, First Ward Council Member, isn’t sure. “The community hasn’t had the best relationship with this company’s presence, so I have reservations and some skepticism about a mere technical solution to deep-seated and ongoing issues that have impacted the community. As it stands, their operation is completely inconsistent with the community’s vision as represented in the River First plan. We’ll continue to monitor the operation of GAF and all of the industrial operations along the riverfront.”
Cunningham summed it up: “I will continue to be in discussions with the constituents that I serve, our environmental officials, and the GAF company to ensure that our community comes first.”