Ethanol plant makes progress on action plan
The consultant, Bill Roddy, is evaluating the plant as part of an “odor action plan” agreed to by the city and plant in response to numerous complaints from neighbors since the plant began operations in 2007.
Roddy will visit Milton on Feb. 8 and 9 to get input from residents and plant and city officials, City Administrator Todd Schmidt told the plan commission Monday.
Roddy has extensive environmental consulting experience with private companies and government agencies in the U.S. and other countries, according to a memo from the plant to the city. He already has visited Milton once to tour the plant and conduct an “odor patrol.”
During his next visit, plant neighbors and city officials will be invited to speak with Roddy one-on-one about their experiences, Schmidt said. A public meeting also will be scheduled so other residents can participate.
Roddy will complete his evaluation sometime after the February visit, said Alan Jentz, vice president of grain operations and risk for United Cooperative, United Ethanol’s parent company.
Jentz and Dennis Hatfield, an environmental consultant for the plant, offered an update Monday on the other requirements of the odor plan:
-- Hire a consultant to examine the plant’s grain dryer. Plant officials have called the dryer—specifically, the regenerative thermal oxidizer that burns up emissions as they come out of the dryer—the most likely primary source of odor at the plant.
Roddy recommended several procedures to minimize emissions and odor from the dryer, including inspecting the system daily and performing preventative maintenance every six months, according to a memo to Jentz dated Friday.
-- Analyze the plant’s odor-complaint log. Roddy analyzed all odor complaints that could be substantiated as probably coming from the plant, according to a memo dated Thursday. He was able to validate 35 percent of the 159 complaints received since 2007.
The validated complaints were attributed to three sources: the drying and thermal oxidation process, the fermentation process and the wastewater pond. More than half were attributed to the drying process.
Complaints originating from the drying process were highest in 2008, before the plant installed a new regenerative thermal oxidizer.
-- Hire a consultant to review emissions tests. Emissions tests conducted in August and September show the plant is in compliance with all air emission standards, Hatfield said. He summarized the results for the commission in a December report.
The plant already has taken steps to improve odor control before Roddy’s evaluation is complete, Jentz said.
In June, the plant started adding a chemical to its emissions stack to destroy acetaldehyde, a chemical that exceeded emissions limits in earlier testing. In November, it installed a data logger to help monitor and record data related to its dryer.