Date of Award

Fall 2017

Project Type

Thesis

Program or Major

Civil Engineering

Degree Name

Master of Science

First Advisor

James P. Malley, Jr.

Second Advisor

Elisabeth Vaudevire

Third Advisor

Weiwei Mo

Abstract

In the drinking water sector, anion exchange technologies are increasingly used for color and disinfection by-products removal, which targets low molecular weight natural organic matter, particularly humic substances (HS). After treatment, resins are regenerated to 99.9% recovery with NaCl resulting in a saline waste stream, referred to as brine. The resulting brine contains left-over NaCl, as well as desorbed inorganic and organic anions (SO42-, HCO3-, HS, etc.) from raw water. Disposal of this brine is a problem, especially with regulations becoming increasingly strict. Fortunately, compounds in the brine can be reclaimed if properly separated: NaCl for direct reuse in the regeneration process; and HS as bio-stimulants for crop growth. Previous investigations highlighted the efficiency of using electrodialysis technology to achieve this separation of 1) NaCl with mono-selective membranes and 2) divalent ions from HS with non-selective membranes. However, little was known about the effect of high organic loads from the brine on operations causing fouling or spacer clogging.

The purpose of this research was to evaluate the long-term feasibility of electrodialysis technology for treatment of an anion exchange brine including NaCl and HS recovery. Electrodialysis treatment with mono-selective membranes was evaluated on pilot scale over a six-month period while recording operational data and quality of the by-products. Additional experiments were also conducted to further understand the overall fouling phenomena and lab-scale simulation of spacer clogging. Results demonstrate that ED treatment with mono- and non-selective membranes is an innovative process, effective at targeting the recovery of resources from concentrated waste streams.

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