After many years of operating with low sulfur coal (instead of the original lignite fuel), TMPA hired AECOM Process Technologies (legacy URS) to upgrade the flue gas desulfurization (FGD) system in anticipation of Mercury Air Toxics Standards (MATS) requirements. To control chlorides in the FGD liquor, a purge stream treatment system was designed to remove suspended solids (which were returned to the FGD system) and provide treatment for both mercury and selenium. AECOM Process Technologies incorporated many of the needed process steps and equipment into the upgraded dewatering facility, saving the client significant time and costs.