POCATELLO — The Idaho Department of Environmental Quality is holding an informational meeting and a formal public hearing this week for local residents to provide feedback on a J.R. Simplot project that would reduce fluoride air emissions at the Don Plant near Pocatello.
The meeting to provide the public with basic information and to address questions will be held at 6 p.m. Thursday at the Pocatello City Council Chambers, 911 N. Seventh Ave., and the formal public hearing will begin immediately afterward at 7 p.m. at the same location, according to a recent news release from the Idaho DEQ.
“This project was proposed by Simplot because fluoride levels were elevated beyond what the state and the EPA consider acceptable,” said Shayne Aytes, the local air quality compliance officer for the Idaho DEQ in Pocatello. “The Environmental Protection Agency and the state DEQ fully support this project, and it certainly is not an inexpensive project.”
Simplot’s Don Plant, located five miles west of Pocatello in Power County, is an integrated ammonium phosphate fertilizer manufacturing plant producing phosphoric acid, sulfuric acid, several grades of solid and liquid fertilizers and other commercial chemical products.
According to the project application Simplot submitted to the Idaho DEQ in April 2022, the Don Plant facility receives phosphate ore as a slurry delivered by an underground pipeline. The slurry is partially dewatered and mixed with sulfuric acid to produce phosphoric acid and a slurried phosphogypsum. The gypsum is pumped to a dewatering stack system for on-site management. The water used to create the slurry and transport the gypsum to the dewatering stack system is decanted and recycled back to the process via decant ponds and a blend tank provides process make-up water.
Currently, three towers located at the Don Plant are used to cool the process water used during the phosphoric acid stages of the process. This process however, has resulted in the Don Plant emitting too much fluoride into the air.
“The cooling towers have various media inside to help spread out the water and then large fans to increase evaporation,” Aytes said. “The towers bring in warm water, use fans to pull in atmospheric air through that warm water causing it to evaporate, which in turn cools what is left behind. Whatever evaporates, however, just goes into the air.”
The proposed project from the Simplot involves replacing the three cooling towers at the Don Plant with about 40 acres of cooling ponds, which function similarly to cooling stacks, only much slower, Aytes said.
“Cooling ponds work on the same principle but instead of having big fans pulling the air through and providing a more rapid cooling of the liquid, it’s a much slower process,” Aytes said. “The pond sort of naturally cools as it tries to come to equilibrium with its surroundings.”
He added, “With cooling ponds, because there’s a lot less energy being put into the system in a very short amount of time, what will happen is that evaporation is so slow that, really, the pollutants of interest, in this case fluoride, don’t really get carried into the air. It’s a much slower process for cooling, but the big win is that not much of the fluoride is going to come out of that pond and go into the atmosphere.”
Originally, the public comment for this project was slated to end on Dec. 14; however, the Idaho DEQ has extended that timeline to end on Friday. All of the application materials are available for public review at DEQ’s State Office in Boise, the DEQ’s Pocatello Regional Office at 444 Hospital Way #300 and on DEQ’s Public Comment Opportunities page.
Those interested in learning more about the project or providing public input are encouraged to attend the public hearing on Thursday.
The formal hearing process will involve taking all public comments, those provided during the meeting and those submitted previously, and formally attaching them to the public record for the project, Aytes said. Underwriters will then take all the comments into consideration before finalizing the permit.
Aaron Hoberg, an air permitting engineer for the Idaho DEQ in Boise, says once the DEQ has reviewed all public comments, it will provide a permit for Simplot to begin construction on the cooling ponds, which he estimates could be issued around the end of January barring any comments that have major implications on the permit application.
Once the construction permit is issued, the proposal is sent to the EPA, which has 45 days to review the plan and issue a permit that will allow Simplot to operate or use the cooling ponds. Hoberg said a good estimate for that permit to arrive from the EPA is around the end of the first quarter in 2023.
*Original full-text article online at: https://www.idahostatejournal.com/news/local/deq-seeking-public-comments-on-j-r-simplot-project-that-would-reduce-fluoride-air-emissions/article_b0cd4e2c-80c4-11ed-ad02-b3905bb8f8be.html
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