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Published May 21, 2014, 09:24 AM

CHS air quality permit under consideration

No comments have been made yet on the Air Pollution Control Permit to Construct requested by CHS for its proposed nitrogen fertilizer plant in Spiritwood, N.D., according to Craig Thorstenson, environmental engineer for the North Dakota Department of Health.

By: Keith Norman, Forum News Service

No comments have been made yet on the Air Pollution Control Permit to Construct requested by CHS for its proposed nitrogen fertilizer plant in Spiritwood, N.D., according to Craig Thorstenson, environmental engineer for the North Dakota Department of Health.

The comment period opened May 5 and extends through June 6.

CHS announced it was in the planning stages for construction of a nitrogen fertilizer plant in September 2012. In April 2014, it delayed an announcement on the project because of higher-than-anticipated costs.

The company has continued with the water and air quality permits while the project is pending. If constructed, the plant would be the largest construction project ever built in North Dakota. Most recent cost estimates exceeded $2 billion.

CHS declined to comment on the permit application process.

“We still could get some comments towards the end of the period,” Thorstenson says. “But the vast majority (of applications) go through the process without comments.”

The announcement issued by the state Health Department at the start of the comment period says preliminary evaluations indicate the project would comply with all applicable air pollution control rules, and there would be no significant detrimental effects to air quality.

That includes the ambient air quality standards set by the federal government. This standard sets maximum concentrations of listed substances and carcinogens possible in the air. A proposed plant meets these standards if its projected emissions, combined with emissions from existing facilities in the area, do not exceed the maximum concentrations.

“The expected combined impact of emissions from the (CHS) facility and all nearby facilities is expected to be below all state and federal ambient air quality standards,” the department report says.

Thorstenson lists particulate matter, nitrogen oxides and ammonia as the principle emissions.

“I wouldn’t anticipate any noticeable odors,” he says, speaking of the ammonia. “It is hard to tell if any would occur, but we’re not expecting significant odors.”

The staff analysis of the emissions done by the state Health Department says it expects an average concentration of 0.327 milligrams of ammonia per cubic meter. The odor threshold is approximately 3.48 milligrams per cubic meter.

Particulate matter is the fine particles associated with combustion. Much of this material will be captured by control equipment, but some will escape into the atmosphere.

The Health Department also performed a carcinogenic risk assessment. This assessment assumed people would be exposed to the emissions for 70 years. The results estimated less than one case of cancer per 100,000 people.

The study also says CHS is using the best available control technology at the plant to limit emissions. Despite those control technologies, CHS will construct 12 emission stacks at the site of the plant.

Five of the stacks are listed as “flare” stacks where excess combustible chemicals would be burned off when the plant is out of balance, Thorstenson says.

“Normally flare stacks are only used in an emergency,” he says. “The height of the flare stacks allows for a dispersion of the pollutants if they are used, but that is in an emergency, not part of the normal operations.”

Thorstenson says the permit application had been under review since September.

“If there are no comments, we move forward,” he says addressing the process of issuing the permit. “If there are comments, we reply to those, and that could take a few weeks.”

Copies of the study are available online at www.ndhealth.gov/ehs/publicnotices.aspx, or written copies are available at the Stutsman County Auditor’s Office.

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