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Sioux Plant ‘Scrubbers’ Go Online
Air Filtration Systems Will Remove More than 95 Percent of Sulfur Dioxide Emissions

A white plume of water vapor from a new, 500-foot stack at Ameren Missouri’s Sioux Plant now signals the successful operation of the plant’s new scrubbers—air filtration systems that remove more than 95 percent of the plant’s sulfur dioxide emissions.

Sioux is a two-unit, 986-megawatt coal-fired power plant, which was completed in 1968. Construction of the scrubbers began in 2006. The project employed more than 600 people at the peak of construction, and will add approximately 20 permanent jobs at the plant. Total project costs were approximately $600 million.

Each generating unit has its own scrubber. As hot flu gas passes through each scrubber, a slurry of crushed limestone and water is sprayed into it. The limestone in the slurry reacts with sulfur in the flu gas, creating synthetic gypsum—an inert material that will be captured and stored in a new landfill on plant property. Gypsum is the main component of wallboard.

“This significant investment demonstrates Ameren Missouri’s commitment not just to cleaner air, but to preparing its power plants to meet customer demand for electricity far into the future,” says Sioux Plant Manager Karl Blank.

The white plume of water vapor will be visible from the plant whenever it is generating electricity, though it will be more visible in colder weather. The new stack consists of two separate liners, one for each of the plant’s generating units. The two original stacks will no longer be used. 

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Contact: Tim Fox, 314.554.4335, tfox@ameren.com

Ameren Missouri has been providing electric and gas service for more than a century, and our electric rates are among the lowest in the nation. The company serves 1.2 million electric and 126,000 natural gas customers in central and eastern Missouri. Ameren Missouri’s mission is to meet their energy needs in a safe, reliable, efficient and environmentally responsible manner. The company’s service area covers 63 counties and 500 towns, including the greater St. Louis area. For more information, visit AmerenMissouri.com.