Use scrubbers.
https://www.watertechonline.com/was...scrubbers-how-they-work-and-why-they-are-usedConclusionThe Clean Air Act requirements have driven development and installation of many technologies to reduce hazardous air pollutants in many industries. Several common approaches for flue gas cleanup applications have been generally described here. Scrubbers of various types are widely used commercially and have been found to be feasible technologies for numerous combustion applications, particularly for coal and oil electric power generation and other heat-dependent applications. Emissions of sulfur and nitrogen oxides, toxic stable organic chemicals, mercury and particulates can be managed to high degrees of removal.
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Combustion processes produce a variety of undesirable products depending on the type of fuel used. Because combustion is an oxidation process, flue gases contain carbon monoxide, carbon dioxide, sulfur oxides, nitrogen oxides, acids and aerosolized metal oxides. They can also contain organics such as polynuclear aromatic hydrocarbons (PAHs) and even polychlorinated dibenzodioxins such as TCDD, as well as inorganic and carbon and other particulates. Fossil fuels such as coal and oil contain contaminants that produce those products, and municipal solid and hazardous wastes contain plastics such as polyvinyl chloride (PVC) that can produce the TCDDs and acids such as hydrochloric acid, in addition to many other products. Because most of those combustion products are harmful to people and the environment, especially in nearby areas where they may be more concentrated in the air and settle onto land and waterways, it is not surprising that numerous regulatory controls and technologies have been developed and are capable of removing many of the combustion products. In the past, tall stacks were expected to achieve sufficient dilution and distribution to minimize risks. Forest fires are also massive producers of most of these products, but they are not controllable sources.
Electric power plants and other high-volume heat-generating processing plants such as steel mills, cement kilns, other industrial facilities as well as municipal incinerators generate much of the combustion gases subject to regulation. U.S. electricity generation that once was heavily coal-based has been shifting to lesser contaminating sources of energy. The U.S. Energy Administration estimated that the fuel mix in 2010 was 45 percent coal, 24 percent natural gas, 20 percent nuclear, 10 percent renewable and 1 percent petroleum, and the shift has increased since then because of the greater availability of lower-cost natural gas. Any carbon combustion produces carbon monoxide and carbon dioxide, but natural gas usually has smaller amounts of precursors to sulfur, nitrogen and metals releases, and it can be burned more efficiently.
