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United Ethanol passes tests for new equipment, fails in other areas

MILTON — United Ethanol's new equipment is operating within permit limits, according to the latest round of state-required testing.

But the plant's good news could be nipped by bad: Other equipment, namely the fermentation scrubber, is over the limit for releasing a pollutant.

The plant on Tuesday submitted to the Wisconsin Department of Natural Resources results from February emissions tests.

Tuesday was the deadline for the plant to turn in the results. The DNR has not reviewed or confirmed the results, said Brian Barbieur, air management engineer.

The tests were required after the plant installed a larger, $2 million regenerative thermal oxidizer in December.

The regenerative thermal oxidizer burns up emissions from the plant's ring dryer, which dries distiller's grain after the ethanol is extracted.

In June, the DNR issued a report listing 170 permit violations at the plant, including emissions violations for particulate matter, volatile organic compounds and nitrogen oxide.

Volatile organic compounds are pollutant gasses. Particulate matter is extremely small particles and liquid droplets made up of acids, chemicals, metals, soil or dust.

Plant officials said the new oxidizer would address some of the permit violations, along with noise and odor issues.

The new regenerative thermal oxidizer met all permit emission limits in testing Feb. 18, according to a letter to the DNR from plant manager Mike Opdahl. DNR officials were present during most of the testing, he wrote.

The plant tested its fermentation scrubber and vent gas scrubber the same week.

The fermentation scrubber tested within limits for volatile organic compounds but over the limit for a specific compound, acetaldehyde, Opdahl's letter said. The compound occurs naturally in many foods, including some fruit, but can cause health problems in people who are overexposed to it, according to the Environmental Protection Agency.

People who are constantly exposed to moderate concentrations of acetaldehyde can experience eye irritation and respiratory problems, the EPA says. Prolonged exposure has caused cancer in animals, the EPA says.

"United Ethanol has hired an expert consultant in scrubber design and operation to investigate the matter and will discuss it with the DNR as soon as the consultant's report is available," plant spokeswoman Dori Lichty said in a statement.

The vent gas scrubber tested over the limit for volatile organic compounds Feb. 19, but on Feb. 20, the plant increased the water flow through the scrubber, dramatically decreasing the compound emissions, Opdahl wrote. The plant has maintained a higher water flow since then.

The plant also performed diagnostic tests of a boiler in February. The boilers had tested well over the limit for particulate matter in past tests.

Plant officials believe that the boilers are testing over the limit because the DNR requires the boilers to fire at their maximum capacities during testing. The plant normally operates the boilers at 60 percent of capacity, Opdahl wrote.

The diagnostic tests confirmed the officials' theory, and officials will continue to talk to the DNR about a solution, he wrote.

"One thing is certain: The United Ethanol boilers are not emitting (particulate matter) at rates indicated by previous testing," he wrote.