Combined Ion Exchange as a Pre- and Post-Treatment for High Pressure

Membrane Systems

Jennifer N. Apell

(M.E., 2009)

Dr. Treavor H.

Boyer

Dr. Katsuki

Kimura

This research was supported by NSF East

Asia and Pacific Summer Institutes (ESPSI)

Program award to JNA.

Flux decline for untreated and pre-treated (9 mL/L

IRA958, 2 mL/L Amberlite 200, 60 min mixing time)

Aldrich humic acid (AHA) synthetic water. Filtration

continued until 70% recovery was achieved.

Overview and Objectives

As membrane water treatment systems increase in use throughout the world, pre-treatment will be needed to prevent

fouling of membranes and post-treatment of the concentrate will be needed for disposal purposes and to reach zero-

liquid discharge. Dissolved organic matter (DOM) and calcium ions are two major foulants of membrane systems

that cause severe fouling and limit system recovery. Research has begun to address membrane pre-treatment

possibilities but is limited in scope. Little research has been conducted to address the treatment of membrane

concentrate.

Combined anion and cation exchange has been previously shown to effectively remove DOM and calcium from

natural water. The following research questions were formulated based on this previous work. Can combined ion

exchange reduce membrane fouling and allow for higher membrane system recovery? Will combined ion exchange

work for both water and wastewater treatment? Accordingly, the objectives of the proposed research are: (1) to

evaluate combined ion exchange as a pre-treatment for high pressure membrane systems and (2) to use combined

ion exchange to treat the concentrate from high pressure membrane systems in order to increase the recovery of pure

water and come closer to attaining zero liquid discharge.

Conclusions

The higher average molecular weight of AHA caused a slower exchange rate with the anion exchange

resins and the removal of AHA suffered from size exclusion.

Calcium exhibited a stronger interaction with SRNOM than AHA causing less removal of calcium in

SRNOM synthetic water than in AHA synthetic water.

Despite combined ion exchange having similar removals of DOC and calcium for both synthetic waters,

combined ion exchange was able to alleviate a substantial amount of fouling for the AHA synthetic water

and a negligible amount of fouling for the SRNOM synthetic water.

Further research is needed to discern the characteristics of organic matter responsible for the difference in

the effectiveness of combined ion exchange and membrane fouling.

Apell, J.N., Boyer, T.H., Kimura, K., 2011. “Combined ion exchange (CIX) as a pre-treatment for high-pressure

membrane systems,” Proceedings of the American Water Works Association Membrane Technology Conference,

Long Beach, California, 28–31 March 2011, 6 pp.

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Treavor H. Boyer, Ph.D. ~ Assistant Professor ~ Department of Environmental Engineering Sciences ~ University of Florida

thboyer@ufl.edu ~ 352.846.3351 ~ www.ees.ufl.edu/homepp/boyer ~ www.twitter.com/WaterWeUpTo