Abstract: The apparatus includes a wet electrostatic precipitator (ESP) field disposed along a combusted fossil-fuel flue gas stream path downstream of a dry ESP field. The wet ESP field includes a chamber having a flue gas inlet and a flue gas outlet, and at least one collection plate positioned within the chamber. The chamber also includes one or more wash nozzle positioned adjacent the collection plate, and a wet hopper positioned substantially under the collection plate. The apparatus preferably further includes one or more cooling nozzles positioned near the flue gas inlet. The cooling and wash nozzles are fluidly coupled to a water source, while the wet hopper is fluidly coupled to either a pH adjustment module or a treatment processor. A method of removing contaminants from a flue gas stream using the above apparatus is also disclosed.