Scrubbers

Communities worldwide often have complicated relationships with coal-fired power plants and manufacturing. While they can bring jobs, tax revenue, and energy to a community, many times they may carry serious public health and environmental issues or concerns due to smokestack emissions. Normally, smokestack emissions are the primary visible way the public is able to distinguish heavy manufacturing from other types of industry and business structures in an area, thus providing a public vocal point for concern. Flue gas desulfurization units, or “scrubbers,” are a technology that has specifically been created to address some of these concerns. As such, they have become increasingly prevalent in modern plant design.

Scrubbers are used in industrial processes to separate unwanted residual solids or particulate matter from emissions or effluent before being released into the air or water. Despite what their name seems to imply, scrubbers do not actually physically scrub away emissions like a chimney sweep cleaning the inside of a chimney. Most scrubbers consist of a material such as limestone that traps emissions as a wet or dry substance in order to prevent the emissions from being released. They traditionally control the emissions of acids (e.g., sulfur dioxide, hydrogen chloride, and sulfuric acid) that cause acid rain, smog, and other types of pollution. Some scrubber technologies claim to reduce unwanted emissions by upward of 80 percent.

Before the use of scrubbers, manufacturers and coal-fired power plants had limited ways to reduce harmful particulate emissions. Over time, this particulate soot changed the color of buildings in industrial cities such as Pittsburgh, Pennsylvania, and London, a physical indication of the air quality, or lack thereof, at the time. The image of a smog-filled Victorian era is due to the increased manufacturing production of the Industrial Age without any way to control emissions and other pollution. The resultant impacts ranged from the cosmetic staining of the local architecture to increased public health dangers. Particulate emissions continue to be a problem in today's society, especially due to increased energy needs.

In the United States, burning coal to produce electricity produces 93 percent of the sulfur dioxide created from manufacturing processes. Much of it can be removed with scrubbers. The first scrubbers were invented in Britain in the 1930s; however, they were not widely used. Early scrubbers are considered to have been first implemented in the late 1960s in order to turn trapped sulfur into solid waste and dispose of it in landfills. This practice led some environmental scientists to argue that scrubbers were turning air pollution or emissions into land pollution or a solid waste sludge, thus swapping one [Page 789]problem for another one. Disposing of solid waste sludge from scrubbers became more difficult as regulation of landfills and landfill locations became more stringent in the mid-1980s and onward. The resulting regulations led to the development of new scrubber technology that could reuse scrubber waste. The new process allowed manufacturers to meet environmental, public health, and manufacturing needs. In this process, more than 35 percent of sulfur waste is turned into a dry powder that can be converted into synthetic gypsum and reused to make drywall and other industrial materials.

...