Flue Gas Desulfurization


Use FMX to meet upcoming 2014 selenium and mercury regulations

The flue gas desulfurization (FGD) process is designed to remove sulfur dioxide from fossil-fuel power plant exhaust. With over 600 coal burning power plants in the United State alone, FGD wastewater is becoming of greater and greater concern. As regulations tighten on contaminant discharge concentrations, the treatment of FGD wastewater is becoming a must.
The goal of this project was to examine the feasibility of using the FMX-NF membrane system to reduce selenium and mercury concentrations in FGD wastewater for discharge.
BKT tested 5 different NF membranes in order to examine the FMX’s treatment capabilities for FGD wastewater. The various membranes were compared based on flux and rejection parameters to determine the ideal membrane for full scale treatment. Given that each plant’s location will be governed by differing discharge regulations, the best membrane may be site depended.
Selenium and sulfate rejection were measured for the tested membranes. Given the various pore sizes tested (150-800 daltons), rejection parameters ranged from 96.4% to 99.6% for selenium, meeting the 10 ug/L limit (FN-SR99 effluent Se concentration was 1.7 ug/L). Sulfate exhibited similar results with rejections ranging from 74.5% to 99.7%. Mercury concentrations were only analyzed for one membrane resulting in a 98.5% rejection.
The flux for the various NF membranes tested ranged from 73 to 253 LMH (43-149 GFD). Flux is a key parameter when designing a full scale FMX system. Due to this factor, it is important to note that flux results from a FMX-B confirmation test are used only for the purpose of performance confirmation for full scale design.