Wet scrubbers remove sulfur from flue gas in coal-fired power plants. The scrubbing agents used in FGD scrubbers are limestone (calcium carbonate) and/or lime and caustic soda. Wastewater from the wet scrubbing FGD process must itself be treated before being released to surface water. FGD wastewater poses a treatment challenge because of the following unique characteristics: high concentrations of total dissolved solids (TDS) and total suspended solids (TSS); high sulfates; high temperature; high organic concentration; ammonia and presence of heavy metals such as arsenic, boron, mercury, and selenium.
Treatment of the FGD blowdown currently consists of blending with cooling tower blowdown to meet EPA discharge requirement.
Current technologies to desalinate the FGD are expensive.
The RDI™ Desalination System offers a cost-effective alternative to conventional technologies for treating this water as the system can tolerate sulfates and reduce the heavy metal content below EPA requirements for drinking water.