In-duct Wastewater Evaporation is a simple, low-cost way of achieving zero liquid discharge from a wet FGD process. Atomized wastewater is evaporated using flue gas upstream of the particulate control device. The dissolved solids form particulate captured with the fly ash for disposal or beneficial use.
AECOM Process Technologies has successfully deployed technology involving the injection of atomized salt solutions for more than a decade. We have the experience, tools, and technology to do this successfully and reliably.
With In-duct Wastewater Evaporation, the purge stream from the wet FGD process is introduced directly into the flue gas using the existing ductwork. The water is evaporated and the suspended and dissolved solids that were present form particulate. By introducing the wastewater upstream of the particulate control device, the additional particulate is collected with the fly ash prior to its disposal or beneficial use.
Depending upon the amount of wastewater that needs to be evaporated, it can either be introduced to the flue gas upstream or downstream of the air heater. If injected prior to the air heater, a slight impact to unit efficiency can result, but a greater volume of wastewater can be eliminated.
By combining this technology with Process Technologies proven ability to minimize the required purge stream from a wet FGD process, we can deliver a cost-effective, overall solution for zero liquid discharge that is fully compliant with the Effluent Limitations Guidelines.