Trona is a mineral found in large quantities in the United States and is similar to baking soda or soda ash.

Trona — or sodium sesquicarbonate — is the raw mineral used to produce baking soda. It is safe to handle, is abundantly available, and has been an effective means of reducing sulfur dioxide (SO2) emissions in industrial and utility applications for more than 20 years.

A dry powder form of trona is injected into the exhaust gas stream. The trona neutralizes and bonds with the SO2, and the dry byproduct is then removed in the particulate emissions control equipment and collected with ash.

Tests show that coal-fired power plants can realize from 40-60 percent reductions in SO2 emissions using this method.

Mirant utilizes a patent-pending trona injection process at its Potomac River Generating Station in Alexandria, Va. This application enables the plant to significantly reduce emissions and operate within regulatory environmental standards.