Civil Engineering ETDs

Publication Date

Summer 7-16-2019


Application of Cation Exchange and Nanofiltration to Treat Flue Gas Desulfurization Wastewater

Ayush Raj Shahi

Bachelor’s in engineering in Civil Engineering

Master of Science in Civil Engineering


Flue gas emitted from coal-fired power plants is one of the major sources of sulfur and nitrogen oxides emissions to the atmosphere. Flue-gas desulfurization (FGD) is a pollution prevention method that is employed to meet regulatory requirements using scrubbers.

FGD wastewater contains high concentrations of dissolved salts which limit options for recycling and reuse. This thesis focused on treating FGD wastewater with a combination of ion exchange (IX), precipitation, and nanofiltration (NF) to improve the recovery of marketable materials and the recycling of water to minimize the disposal of wastewater. For IX, resins were used to perform laboratory batch and column experiments to determine the selectivity of the resin, design parameters and limitations for the removal of calcium. Nanofiltration (NF) was used for the removal of sulfate ions from the wastewater using NF membranes. Removal of trace contaminants, such as arsenic, mercury, nitrate, and selenium were studied in this process.


Ion Exchange, Nanofiltration, Flue Gas Desulfurization, Wastewater, Gypsum, Brucite


Department of Energy

Document Type




Degree Name

Civil Engineering

Level of Degree


Department Name

Civil Engineering

First Committee Member (Chair)

Dr. Kerry Howe

Second Committee Member

Dr. Bruce Thomson

Third Committee Member

Dr. Abdul-Mehdi S. Ali