Alternative Thermal Process For Flue Gas Desulphurization (FGD) Scrubber Blowdown - The CoLD™ Process

By HPD, a Veolia Water Solutions & Technologies Company

Environmental regulations are looming which may have the practical effect of requiring zero liquid discharge (ZLD) wastewater treatment for some power plants using wet limestone scrubbers. In ZLD processes, industrial wastewater is reduced to a solid which is usually landfill disposed. Any recovered water from the ZLD treatment process is recycled and reused in the plant.

Conventional ZLD evaporation crystallization processes for evaporation-Flue Gas Desulfurization (FGD) scrubber blowdown waste streams have numerous drawbacks and shortcomings.

These processes require clarification and extensive pre-treatment of the wastewater with lime, soda ash, and other chemicals to replace the calcium, magnesium, and heavy metal ions in the wastewater with sodium ions in order to produce a solid for landfill disposal.

Pre-treatment equipment and chemicals increase the footprint of the ZLD system as well as the capital costs and overall maintenance of the overall wastewater treatment plant.