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Combined Ion Exchange for the Simultaneous Removal of Dissolved Organic Matter and Hardness

Permanent Link: http://ufdc.ufl.edu/UFE0041287/00001

Material Information

Title: Combined Ion Exchange for the Simultaneous Removal of Dissolved Organic Matter and Hardness
Physical Description: 1 online resource (73 p.)
Language: english
Creator: Apell, Jennifer
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: byproducts, disinfection, exchange, hardness, ion, matter, natural, organic
Environmental Engineering Sciences -- Dissertations, Academic -- UF
Genre: Environmental Engineering Sciences thesis, M.E.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Dissolved organic matter (DOM) and hardness cations are two common constituents of natural waters that substantially impact water treatment processes. Anion exchange treatment, and in particular magnetic ion exchange (MIEX), has been shown to effectively remove DOM from natural waters. An important advantage of the MIEX process is that it is used as a slurry in a completely mixed flow reactor at the beginning of the treatment train. Hardness ions can be removed with cation exchange resins, although typically using a fixed bed reactor at the end of a treatment train. In this research, the feasibility of combining anion and cation exchange treatment in a single completely mixed reactor for treatment of raw water was investigated. The sequence of anion and cation exchange treatment, the number of regeneration cycles, and the chemistry of the regeneration solution were systematically explored. Simultaneous removal of DOM ( > 70% dissolved organic carbon) and hardness ( > 50% total hardness) was achieved by combined ion exchange treatment. This treatment would prove useful for raw waters that are a mixture of groundwater and surface water and as a pre-treatment for membrane systems as both DOM and calcium are major foulants.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Jennifer Apell.
Thesis: Thesis (M.E.)--University of Florida, 2009.
Local: Adviser: Boyer, Treavor H.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2011-12-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0041287:00001

Permanent Link: http://ufdc.ufl.edu/UFE0041287/00001

Material Information

Title: Combined Ion Exchange for the Simultaneous Removal of Dissolved Organic Matter and Hardness
Physical Description: 1 online resource (73 p.)
Language: english
Creator: Apell, Jennifer
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: byproducts, disinfection, exchange, hardness, ion, matter, natural, organic
Environmental Engineering Sciences -- Dissertations, Academic -- UF
Genre: Environmental Engineering Sciences thesis, M.E.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: Dissolved organic matter (DOM) and hardness cations are two common constituents of natural waters that substantially impact water treatment processes. Anion exchange treatment, and in particular magnetic ion exchange (MIEX), has been shown to effectively remove DOM from natural waters. An important advantage of the MIEX process is that it is used as a slurry in a completely mixed flow reactor at the beginning of the treatment train. Hardness ions can be removed with cation exchange resins, although typically using a fixed bed reactor at the end of a treatment train. In this research, the feasibility of combining anion and cation exchange treatment in a single completely mixed reactor for treatment of raw water was investigated. The sequence of anion and cation exchange treatment, the number of regeneration cycles, and the chemistry of the regeneration solution were systematically explored. Simultaneous removal of DOM ( > 70% dissolved organic carbon) and hardness ( > 50% total hardness) was achieved by combined ion exchange treatment. This treatment would prove useful for raw waters that are a mixture of groundwater and surface water and as a pre-treatment for membrane systems as both DOM and calcium are major foulants.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Jennifer Apell.
Thesis: Thesis (M.E.)--University of Florida, 2009.
Local: Adviser: Boyer, Treavor H.
Electronic Access: RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2011-12-31

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0041287:00001


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1 COMBINED ION EXCHANGE FOR THE SIMULTANEOUS REMOVAL OF DISSOLVED ORGANIC MATTER AND HARDNESS By JENNIFER NICOLE APELL A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORID A IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ENGINEERING UNIVERSITY OF FLORIDA 2009

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2 2009 Jennifer Nicole Apell

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3 To Dr. Treavor H. Boyer

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4 ACKNOWLEDGMENTS I would like to thank Orica Watercar e for providing t he MIEX-Cl and MIEX-Na resins and Neil Doty at the Cedar Key Wa ter & Sewer District for assistance with collecting raw water samples.

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5 TABLE OF CONTENTS Page ACKNOWLEDG MENTS .................................................................................................. 4LIST OF TABLES ............................................................................................................ 7LIST OF FI GURES .......................................................................................................... 9ABSTRACT ................................................................................................................... 12CHAPTER 1 OVERVIEW AND OBJECTIV ES ............................................................................. 132 MATERIALS A ND METHOD S ................................................................................ 17Material s ................................................................................................................. 17Preliminary Experim ental Wo rk ............................................................................... 18Jar Test Pr ocedure ................................................................................................. 18Shaker Table Procedur e ......................................................................................... 20Regeneration of Ion Exchange Re sin ..................................................................... 20Analytical Methods .................................................................................................. 223 RESULTS AND DI SCUSSION ............................................................................... 24Cedar Key Water .................................................................................................... 24Preliminary Experim ental Wo rk ............................................................................... 24Magnetically-Enhanced Cation Exchange Treat ment ............................................. 25Combined Cation and Anio n Exchange Treat ment ................................................. 28Simultaneous Versus Sequential Comb ined Ion Exchan ge Treatment ................... 29Influence of Regeneration Paramete rs on Removal E fficiency ............................... 32Applications of Combined Ion Exchange Tr eatment ............................................... 354 CONCLUS IONS ..................................................................................................... 45Conclusi ons ............................................................................................................ 45Recommendations for Fu rther Res earch ................................................................ 45APPENDIX A PRELIMINARY EXPERIMENT AL WORK R ESULTS ............................................. 47B HARDNESS RESULTS FO R EXPERIMENTAL WORK ......................................... 51C DOC and TN RESULTS FO R EXPERIMENTAL WORK ........................................ 54D UV254 and SUVA RESULTS FOR EXPERIMENTAL WORK .................................. 58

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6 E CHLORIDE and SULFATE RESULT S FOR EXPERIMENT AL WORK................... 61F EEMs for selected expe rimental work ..................................................................... 65LIST OF RE FERENCES ............................................................................................... 69BIOGRAPHICAL SKETCH ............................................................................................ 73

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7 LIST OF TABLES Table Page 3-1 Characteristic of Cedar Key raw wate r used in ion exchange experiments. ....... 363-2 Preliminary jar test result s for fresh MIEXNa resi n. ........................................... 373-3 Comparison of finished water qua lity for combined ion exchange and municipal drin king wate r ..................................................................................... 373-4 Comparison of regeneration solutions pr epared from DI water and tap water. ... 37A-1 Hardness results for prelim inary experiment al work .......................................... 47A-2 Dissolved organic carbon and tota l nitrogen results for preliminary experimental work. ............................................................................................. 48A-3 UV254 and SUVA results for prelim inary experiment al work ............................... 49A-4 Chloride and sulfate results fo r preliminary exper imental work........................... 50B-1 Hardness removal comparison of brine and acid/base regeneration for 16 mL/L MIEXNa. ................................................................................................... 51B-2 Hardness removal of simultaneous treatment using 16 mL/L MIEX-Na and (unregenerated) 2 mL/L MIEX-Cl and a dose of 2 mL/L regenerat ed MIEX-Cl. 51B-3 Hardness removal for sequential tr eatments using 16 mL/L MIEX-Na and (regenerated) 2 mL/L MIEX-Cl. ........................................................................... 52B-4 Hardness removal for simultaneous tr eatment using 16 mL/L MIEX-Na and 2 mL/L (regenerated) MIEXCl............................................................................... 52B-5 Hardness removal for simultaneous tr eatment using 16 mL/L MIEX-Na and 2 mL/L (regenerated) MIEX-Cl with the reuse of a tap water regeneration solution (1 L singlet jar test s). ............................................................................. 53B-6 Hardness removal over ti me for 16 mL/L MIEX-Na. ........................................... 53C-1 Organics removal comparison of br ine and acid/base regeneration for 16 mL/L MIEXNa. ................................................................................................... 54C-2 Organics removal of simultaneous tr eatment using 16 mL/L MIEX-Na and (unregenerated) 2 mL/L MIEX-Cl and a dose of 2 mL/L regenerat ed MIEX-Cl. 55C-3 Organics removal for sequential treat ments using 16 mL/L MIEX-Na and (regenerated) 2 mL/L MIEX-Cl. ........................................................................... 56

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8 C-4 Organics removal for simultaneous tr eatment using 16 mL/L MIEX-Na and 2 mL/L (regenerated) MIEXCl............................................................................... 57D-1 UV254 removal comparison of brine and ac id/base regeneration for 16 mL/L MIEX-Na ............................................................................................................ 58D-2 UV254 removal of simultaneous treatm ent using 16 mL/L MIEX-Na and (unregenerated) 2 mL/L MIEX-Cl and a dose of 2 mL/L regenerat ed MIEX-Cl. 58D-3 UV254 removal for sequential treatm ents using 16 mL/L MIEX-Na and (regenerated) 2 mL/L MIEX-Cl. ........................................................................... 59D-4 UV254 removal for simultaneous treatm ent using 16 mL/L MIEX-Na and 2 mL/L (regenerated) MIEX-Cl. .............................................................................. 59 D-5 UV removal for simultaneous treatm ent using 16 mL/L MIEX-Na and 2 mL/L (regenerated) MIEX-Cl with the reuse of a tap water regeneration solution (1 L singlet jar tests) .............................................................................................. 60E-1 Chloride addition and sulfate remova l comparison of brine and acid/base regeneration for 16 mL /L MIEX-Na. .................................................................... 61E-2 Chloride addition and sulfate remova l of simultaneous treatment using 16 mL/L MIEX-Na and (unregenerated) 2 mL /L MIEX-Cl and a dose of 2 mL/L regenerated MI EX-Cl. ......................................................................................... 62E-3 Chloride addition and sulfate remo val for sequential treatments using 16 mL/L MIEX-Na and (regenerated) 2 mL/L MI EX-Cl. ........................................... 63

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9 LIST OF FIGURES Figure Page 2-1 Dosing flowchart for simultaneous and sequenced jar test s procedures. ........... 203-1 Preliminary results for MIEX-Cl resin compared with MIEX-Cl regenerated before first use. ................................................................................................... 383-2 Comparison of sulfate and DOC remo val by MIEX-Cl resin with and without prior regenerat ion. .............................................................................................. 383-3 Impact of brine and acid/base reg eneration procedures on hardness removal by magnetic cation exchange using 16 mL/L MIEX-Na resin. ............................ 393-4 Comparison of DOM and hardness re moval by cation, anion, and combined ion exchange treatment using 2 mL/L MIEX-Cl and 16 mL/L MIEX-Na resins after three regener ation cycl es. .......................................................................... 393-5 Comparison of simultaneous and sequential ion exch ange treatment on removal of (a) hardness, (b) DOC, and (c) UV254. All jar tests used 16 mL/L MIEX-Na resin and 2 mL/L MIEX-Cl resi n. ......................................................... 40 3-6 Fluorescence EEMs for (a) Cedar Ke y water (5.4 mg C/L, 277 mg/L as CaCO3), (b) MIEX-Cl treatment (1.3 mg C/L, 273 mg/L as CaCO3), and (c) MIEX-Na treatment (4.7 mg C/L, 120 mg/L as CaCO3). ..................................... 423-7 Effect of the ratio of NaCl to MIEX-Na resin on regeneration efficiency and hardness remo val. .............................................................................................. 433-8 Effect of varying reaction ti me and regeneration time on regeneration efficiency and hardness removal by MIEX-Na resin. .......................................... 433-9 Regeneration efficiency and resin ut ilization based on the equivalence ratio used during regener ation. ................................................................................... 443-10 Theoretical reduction in fouling ca used by dissolved organic matter and calcium sulfate pr ecipitat ion................................................................................ 44F-1 EEMs for (left) raw water and (r ight) 2 mL/L unregener ated MIEX-Cl treated water. .................................................................................................................. 65F-2 EEMs for (left) raw water, (center ) 16 mL/L MIEX-Na treated water, and (right) 8 mL/L Amberlite-Na treated wa ter. ......................................................... 65F-3 EEMs for (left) raw water and simu ltaneous treatment using 16 mL/L MIEXNa and 2 mL/L unregener ated MIEXCl. ............................................................ 66

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10 F-4 EEMs for (top left) raw water for (t op right) simultaneous treatment using 16 mL/L MIEX-Na and 2 mL/L unregenerated MIEX-Cl and the (bottom left) raw water for (bottom right) 16 mL/L MIEX-Na and 2 mL/L MIEX-Cl that had been through four regener ation cycl es. ....................................................................... 67F-5 EEMs for (left) raw water, (center ) 16 mL/L MIEX-Na treated water, and (right) 2 mL/L MIEX-Cl treated water with resin that had been through two regeneration cycles. ........................................................................................... 68F-6 EEMs for (left) raw water (right) fo r simultaneous treatment using 16 mL/L MIEX-Na and 2 mL/L MIEX-Cl that had been through two regeneration cycles. ................................................................................................................ 68

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11 LIST OF ABBREVIATIONS DOC Dissolved organic carbon; experim entally defined as the carbon concentration that can pass through a 0.45 m nylon filter DOM Dissolved organic matter L Liter M Molar meq Milliequivalent MIEX Magnetically-enhanced ion excha nge resin manufactured by Orica Watercare MIEX-Cl Anion MIEX resin loaded with ch loride as the mobile counter ion MIEX-Na Cation MIEX resin loaded with so dium as the mobile counter ion min Minute mL Milliliter NOM Natural organic matter Regen. Regenerated / Regeneration rpm Rotations per minute SUVA / SUVA254 Specific ultraviolet absorbance at 254 nm; defined as UV254 divided by the dissolved organic carbon concentration TN Total nitrogen UV254 Ultraviolet absorbance at 254 nm

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12 Abstract of Thesis Pres ented to the Graduate School of the University of Florida in Partial Fulf illment of the Requirements for t he Degree of Master of Engineering COMBINED ION EXCHANGE FOR THE SIMULTANEOUS REMOVAL OF DISSOLVED ORGANIC MATTER AND HARDNESS By Jennifer Nicole Apell December 2009 Chair: Treavor H. Boyer Major: Environmental Engineering Sciences Dissolved organic matter (DOM) and hardness cations are two common constituents of natural waters that subst antially impact water treatment processes. Anion exchange treatment, and in particula r magnetic ion exch ange (MIEX), has been shown to effectively remove DOM from natur al waters. An important advantage of the MIEX process is that it is used as a slurry in a completely mixed flow reactor at the beginning of the treatment train. Hardness ions can be removed with cation exchange resins, although typically using a fixed bed reacto r at the end of a treatme nt train. In this research, the feasibility of combining ani on and cation exchange tr eatment in a single completely mixed reactor for treatment of raw water was investigated. The sequence of anion and cation exchange treatment, the number of regenerat ion cycles, and the chemistry of the regeneration solution we re systematically explored. Simultaneous removal of DOM (>70% dissolved organic carbon) and hardness (>50% total hardness) was achieved by combined ion exchange treatm ent. This treatment would prove useful for raw waters that are a mixture of groundwater and surface water and as a pretreatment for membrane systems as both DOM and calcium are major foulants.

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13 CHAPTER 1 OVERVIEW AND OBJECTIVES Dissolved organic matter (DOM) and har dness cations (i.e., calcium and magnesium) are common constit uents of natural water that have a substantial impact on physical-chemical unit processes and fi nished water quality. DOM is undesirable because it imparts taste, odor, and colo r to water (Cohn et al., 1999); increases chemical requirements for oxi dation, coagulation, and disinfec tion (Kitis et al., 2007); and is a precursor to disinfection by products (DBPs) (Johnson and Singer, 2004). Hardness cations are primarily an economic concern for domestic water users. In addition, many industrial processes require hardness-free water to prevent scaling. Of increasing importance is the fact that both DOM and calcium have been shown to cause reversible and irreversible fouling of membr anes (Kimura et al., 2004; Saravia et al., 2006; Fabris et al., 2007; Gray et al., 2007). Coagulation is a common unit process us ed to remove DOM (Dempsey et al., 1984), while lime softening is commonly used for removal of hardne ss (Mercer et al., 2005). Coagulation and lime softening, however, have lim itations. For example, coagulation is limited to removal of ultrav iolet-absorbing DOM (Archer and Singer, 2006), while lime softening is limited by the so lubility of calcite and removal of carbonate hardness (Stumm and Morgan, 1996). Therefore, alternative treatment processes for removal of DOM and hardness are sought that could provide benefits over traditional treatment. Ideally, a combined anion and cati on exchange process is envisioned that would remove both DOM and hardness, and thereby replace co agulation and lime softening with a single unit process. The bas is for combined ion exchange treatment for removal of DOM and hardness is discussed below.

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14 Anion exchange, and in particular magnetic ion exchange (MIEX), is an alternative to coagulation for DOM removal (Singer and B ilyk, 2002; Boyer and Si nger, 2005; Jarvis et al., 2008). MIEX resin is designed to be used as a slurry in a co mpletely mixed flow reactor or fluidized bed reactor (Boyer and Singer, 2006; Singer et al. 2009). As a result, MIEX resin is used as a pre-treatment proce ss to treat unfiltered wa ter at the beginning of a treatment train. MIEX resin has been previously shown to be very effective for removal of DOM (Humbert et al., 2005; Kitis et al., 2007; Mergen et al., 2008; Zhang et al., 2008). The substantial reduction in DO M by MIEX pre-treatment results in decreased chemical requirements and r educed formation of DBPs (Johnson and Singer, 2004; Kitis et al., 2007). In addition, research has shown that anion exchange and MIEX pre-treatment have t he potential to reduce membr ane fouling by DOM when resin carryover is controlled (Fabris et al., 2007; Zhang et al., 2008). Cation exchange is an alternative to lim e softening for hardness removal, and has been extensively used for point-of-use water softening. In municipal water treatment plants, cation exchange resin is traditionally used in a fixed bed reactor at the end of a treatment train. Orica Waterc are, the manufacturer of MIEX resin, recently developed a weak-acid, magnetic cation exchange resin specifically designed for removal of hardness. This resin is designed to be used in a suspended manner as a pre-treatment process for hardness removal, similar to traditional MIEX resin for DOM removal. Although cation exchange treatment is less common than softening in municipal water treatment plants, recent research has shown that cation exchange is beneficial as a pretreatment for membrane systems (Corneliss en et al., 2009; Heijman et al., 2009). Cation exchange is used to remove calcium and other divalent cations to prevent

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15 precipitation of sparingly soluble minerals, such as calcium sulfate and calcium carbonate, and to minimize enhanced foulin g by DOM on membrane surfaces (Li and Elimelech, 2004). For example, Cornelissen et al. (2009) showed a 10% decrease in irreversible fouling on an ultrafiltration membrane when raw water was treated with cation exchange resin in a fluidized bed. Heijm an et al. (2009) were able to achieve a 97% recovery in a nanofiltration system with t he use of a cation exchange fluidized bed that removed 99% of divalent cations. Thus, combined anion and cation exchange is expected to substantially decrease membra ne fouling by simultaneously removing DOM and divalent cations. Although previous researchers have in vestigated anion exch ange for removal of DOM and cation exchange for removal of hardness, none of the previous work combined both anion and cation exchange into a single unit process for simultaneous removal of DOM and hardness. It is also not known how the interactions between DOM and hardness cations would affect the anion and cation exchange reactions. The potential benefits of combi ned ion exchange for remo val of DOM and hardness are elimination of sludge from coagulation and lime softening, ability to use a single completely mixed flow reactor or fluidized bed reactor at th e head of the treatment train, and removal of both organic and i norganic membrane foulants. The overall goal of this work is to ev aluate the removal of DOM and hardness by combined anion and cation exchange treatment. T he specific objectives of this work are: (1) to evaluate the effe ctiveness of a magnetically-enhanced cation exchange resin; (2) to compare removal e fficiencies for anion, cation, and combined ion exchange treatment; (3) to evaluate the effect that simultaneous versus sequential combined ion

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16 exchange treatment has on removal efficien cies; (4) to determine the influence of regeneration parameters on re moval efficiencies; and (5 ) to discuss additional applications of combi ned ion exchange treatment.

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17 CHAPTER 2 MATERIALS AND METHODS Materials All experiments were conducted using groundw ater from Cedar Key, FL collected from Well 4 of the Cedar Key Water & Sewer Distric t. Groundwater was collected in November 2008 and January, February, and April 2009. Magnetically enhanced anion and cation e xchange resins, manufactured by Orica Watercare, were evaluated in this work. In previous literature, the magnetic anion exchange resin is referred to as MIEX resin. In this work, the magnetic anion exchange resin will be referred to as MIEX-Cl (i.e., ch loride is the mobile counter anion) and the magnetic cation exchange resin will be referr ed to as MIEX-Na (i.e., sodium is the mobile counter cation). Both resins have a polyacrylic backbone, macroporous structure, and contain magnetic iron oxide. In addition, the MIEX-Cl and MIEX-Na resins are designed to be used in a suspended manner in a completely mixed flow reactor, as discussed previously. The MIEX-Cl resin is a strong-base anion exchange resin with quaternary amine functional groups, and has a volumetric anion exchange capacity of 0.52 milliequivalents (meq) per mL resin (Boyer and Singer, 2008). Additional discussion of anion exchange resin properties is provided elsewhere (Boyer and Singer, 2008). The MIEX-Na resin is a weak-acid ca tion exchange resin with carboxylic acid functional groups. Weak-acid cation exchange resins are typically used in the hydrogenform at acidic pH values (Clifford, 1999). At neutral to basic pH values, weak-acid resins function much like strong-acid resins, and are ty pically used in the sodium form (Clifford, 1999). The MIEX-Na resin was assumed to have a cation exchange capacity of 0.52 meq/mL because it was functionalized from the same starting material as the MIEX-Cl

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18 resin. All ion exchange resins were dosed vo lumetrically by measuring the volume of wet settled resin using a graduated cylinder. ACS grade chemicals were used for all ex perimental procedur es and analytical methods. Standard chemicals used for total organic carbon and total nitrogen analyses were provided by the manufacturer. Deioni zed (DI) water was used to prepare all chemical reagents and standards. Glassware was cleaned by rinsing with DI water and, if necessary, a 6% nitric acid solution. Preliminary Experimental Work Preliminary experiments we re conducted to determine the MIEX dose that could remove 50% total hardness and 50% dissolv ed organic carbon (DOC) from Cedar Key raw water. MIEX-Cl was used as delivered and MIEX-Na was regenerated to convert all mobile ions to sodium. The regeneration proc edure is described in the Regeneration of Ion Exchange Resin section below. After MI EX-Cl resin was regenerat ed, a substantial increase in DOC and UV254 removal was seen. MIEX-Cl was then regenerated in the same manner as MIEX-Na before all further tests. Jar Test Procedure A Phipps & Bird PB-700 jar tester with 2 L square jars was used to conduct batch tests with ion exchange resin. Two liters of Cedar Key raw wa ter was added to each jar. The ion exchange resin was measured and added to the jars. The resin was mixed for 20 min at 100 rpm and allowed to settle for 30 min. A sample was taken from each jar from a spigot in the jar. All ion exc hange experiments were conducted using duplicate doses of ion exchange resin, and all result s are shown as average values with error bars corresponding to one standard deviation for duplicate resin doses, except where noted otherwise.

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19 Individual anion and cation exchange jar te sts were conducted as described in the previous paragraph. In addition, three types of combined ion exchange experiments were performed: (1) simultaneous anion an d cation exchange, (2) sequential anion exchange followed by cation exchange (S equence 1), and (3) sequential cation exchange followed by anion exchange (Sequence 2). For all combined ion exchange experiments, anion and cation exchange resins were measured separately in graduated cylinders and then added to a single jar at t he appropriate time during the experiment. Initial jar tests were conducted with fresh ion exchange resin, which is defined in the Regeneration of Ion Exchange se ction below. After the initial jar test, the resin from the duplicate jars was combined for regeneration, which is also described in the same section. The combined resin was split into duplicate doses with the assumption that the anion and cation exchange resins were evenly distributed. Subsequent jar tests were conducted with regenerated resin, and the tests are referred to as the number of times the resin was regenerated (e.g., regen. 1 ). Sequences 1 and 2 followed the general procedure described above, with t he following additional steps. Three jars were used for the first stage of treatment with either anion or cation exch ange resin. After the first treatment stage, at least four liters of treated water was decanted from the three jars, and two liters each of treated water was transferred to two clean jars. The complementary ion exchange re sin was added to the new jars for the second stage of treatment. A sample from each jar was taken after the second treatment stage. Raw and treated water samples were measur ed for pH, total hardness, alkalinity, ultraviolet (UV) absorbance, dissolved or ganic carbon (DOC), total nitrogen (TN), fluorescence intensity, chlo ride, sulfate, and nitrate.

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Figure 2 An mL Erle n in a 1.2 and mix Ion Exc h NaCl so equival e rpm. Vi r to beco m contain e 2 -1. Dosing n Innova 20 n meyer fla s M CaCl2 s o ing for 15 h h ange Res i lution, and e nce ratio. T r gin anion a m e fresh r e e d 10 time s flowchart f 00 Platfor m s ks. MIEXN o lution that h ours. The i n section b the molari t T he sampl e Reg e a nd cation e e sin. Both M s more sodi f or simulta n Shaker T m Shaker ( N N a resin w a had an eq u resin was t b elow. One t y of the so l e s were pl a e neration o e xchange r M IEX-Cl an d um or chlo r 20 n eous and s T able Proc e N ew Bruns w a s pre-loa d u ivalence r a hen rinsed mL of MIE X l ution was a a ced on the o f Ion Exc h esins were d MIEX-Na r ide than w s equenced e dure w ick Scient d ed with cal a tio of 200 as describ e X -Ca resin a ltered to r e platform s h h ange Res regenerat e were rege n w as theoreti c jar tests p r ific) was u s cium by pl a meq Ca2+ p e d in the R was place d e ach the d e h aker for 1 2 in e d before t h n erated in a c ally avail a r ocedures. s ed with 12 a cing the r e p er meq M I egeneratio d in 50 mL e sired 2 hours at 2 h eir initial u a solution t h a ble on the 5 e sin I EX n of of 2 00 u se h at

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21 resin, based on an ion exchange capacity of 0.52 meq/mL. For example, 2 mL/L of MIEX-Cl resin has a capacity of 1.04 meq/L, and a 10 times sodium chloride solution has a concentration of 10.4 meq/L as chlo ride (or 10.4 mM as chloride). Although MIEXCl is shipped in the chloride form, prelim inary jar tests showed an increase in DOC removal with regeneration, suggesting that th e anion exchange sites on the virgin resin were not fully saturated with chloride. MIEX-Na is shipped as a mixture of sodium and hydrogen mobile ions, so it was regenerated to convert a ll mobile ions to sodium. The resins were regenerated after each jar test as follows Excess water was decanted from the jars and the resin was rinsed once with DI water. All regeneration solutions had a sodium chloride concentrati on of ~2 M, unless noted otherwise. The baseline regeneration pr ocedure used a brine solution that contained 25 times more sodium chloride (on a meq/L basis) than was t heoretically available on the resin. This was achieved by adjusting the ratio of the volu me of regeneration solution to the volume of MIEX resin. The regeneration solution and resin were mixed on a stir plate for 30 min and allowed to settle for 10 min before decant ing the brine. The c ontainer was filled with DI water, mixed for 10 min, settled fo r 10 min, decanted, and repeated for a second time. The cation and anion exchange resins were combined for the simultaneous ion exchange tests, so the amount of sodium chloride used for regeneration was dependent on the amount of cation exchange resin pr esent. Consequently, the brine solution was 8 times stronger for the anion exchange resin than it was fo r the cation exchange resin because of the dosages of resin. For Sequences 1 and 2, the cation and anion exchange resins were regenerated separately, and therefore, the ratio of sodium chloride to resin, on a meq/L basis, was constant at 25 for both resins.

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22 The MIEX-Na resin was also regenerated using a series of acid and base solutions as follows. The resin was stirred in DI water while hydrochloric acid was added until pH 3 was reached. This step converts the resin to the hydrogen form. Sodium hydroxide was then added until pH 11 to conver t the resin to the sodium form. The same rinsing procedure was followed. Analytical Methods Samples requiring filtration were filter ed through 0.45 m nylon membrane filters (Millipore). All filters were pre-rinsed with 500 mL of DI water followed by 15 mL of sample. Filtered water was used for all anal yses except pH, alkalinity, and total hardness. An Accumet AP71 pH meter with a pH/ATC probe was used to measure pH. The pH meter was calibrated before each use with pH 4, 7, and 10 buffer solutions. Alkalinity and total hardness were det ermined following Standard Method 2320 and 2340, respectively (American Public Health Association, (1998)). UV absorbance at 254 nm (UV254) was measured on a Hitachi U-2900 spectrophotometer using a 1 cm quartz cell. Fluorescence excita tion-emission matrix (EEM) spectra were collected on a Hitachi F-2500 fluorescence spectrophotometer using a 1 cm quartz cell. Samples were scanned at 5 nm increments over an excitation (EX) wavelength = 200–500 nm and at 5 nm increments over an emission (EM) wavelength = 200–600 nm. The raw EEMs we re processed in MATLAB following published procedures (Cory and McKnight, (2005)). A DI water EEM, which was analyzed daily, was subtracted from the samp le EEM; the area under the Raman water peak (EX = 350 nm) was calculated for DI water; intensity values of the sample EEM were normalized by Raman water area; and EEMs were plotted in MATLAB using the contour function with 20 contour lines.

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23 DOC and TN were measured on a Shimadzu TOC-VCPH total organic carbon analyzer equipped with a TNM-1 total nitrogen measuring unit and an ASI-V autosampler. All DOC and TN samples were measured twice wit h average values reported. The relative difference betw een DOC and TN duplicat e measurements was <10% and <15%, respectively. The relative di fference was calculated by subtracting the two values and dividing by the average. St andard checks were within 10% of the known value. Chloride, nitrate, and sulfate were measured on a Dionex ICS-3000 ion chromatograph equipped with IonPac AG22 guar d column and AS22 analytical column. All inorganic anions were measured in dupl icate with average values reported. The relative difference between duplicate m easurements was <5%. Standard checks were within 10% of the known value. The aqueous concentration of metal cations was determined by acidifying samples to pH <2 wi th concentrated nitric acid (Trace Metal Grade, Fisher Scientific) and measuring on an ICP-AES (Thermo Jarrell Ash) as described in the US EPA Method 6010B.

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24 CHAPTER 3 RESULTS AND DISCUSSION Cedar Key Water The average composition of Cedar Key gr oundwater is shown in Table 3-1. The minimum and maximum parameter values show that the water quality was relatively constant over the study timeframe, as would be expected for a groundwater. The relatively high concentrations of DOC and hardness in Cedar Key groundwater are common for a groundwater that has been infiltrated by a surface water. Furthermore, this is a water source that requires subs tantial treatment to prevent the problems associated with elevated concentrations of DOM and hardness, such as DBP formation and membrane fouling. The average specific UV254 absorbance (SUVA254) of Cedar Key raw water was 3.1 L/mgCm, wh ich together with the low sulf ate concentration indicates that MIEX-Cl treatment will be effective fo r DOM removal (Boyer and Singer, 2006). Greater than 90% of the hardnes s was as calcium. This is important because calcium and DOM form strong inner-sphere complexe s, while magnesium and DOM do not interact (Kalinichev and Kirkpatrick, 2007). Preliminary Experimental Work Three preliminary doses of 0.5, 1, and 2 mL of virgin MIEX-Cl resin per L of Cedar Key raw water were tested in the preliminary work. The dose of 2 mL/L was found to remove about 53% of DOC and 60% of UV254 and was therefore chosen for all further research. The DOC, UV254, TN, and SUVA254 results from the th ree preliminary doses can be found in Figure 3-1. Also located in that figure for comparison is the results from a 2 mL/L MIEX-Cl dose that had been regenerated bef orehand to become fresh resin. It can be seen that UV254 and DOC removal steadily increase as the resin dose increases

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25 and that there is a small decline in SUVA. T he raw water SUVA for the preliminary tests was 3.4 L/mgCm, which means that the dos e of 2 mL/L caused a decrease of 0.5 to reach the SUVA of 2.9 L/mg Cm. The raw water SUVA for the 2 mL/L regenerated MIEX-Cl resin dose was 3.0 L/mgCm and decr eased to 1.5 L/mgCm, a difference of 1.5. This difference is caus ed by a greater removal of UV254 compounds than overall DOC. Figure 3-2 shows the difference that regeneration causes in sulfate and DOC removal for the 2 mL/L MIEX-Cl dose. Only a 4% increase in sulfate removal is seen while there is a 22% increase in DOC removal. This is significant because sulfate is the major competitor of organic matter for ion exchange sites on MIEX-Cl resin. All supplementary data for preliminary work can be found in Appendix A. Magnetically-Enhanced Cation Exchange Treatment Preliminary jar tests were conducted us ing the magnetic cation exchange resin (i.e., MIEX-Na) to evaluate the relationshi p between hardness removal and resin dose. The treatment goal was to achieve at leas t 50% hardness removal. The change in water chemistry following magnetic ca tion exchange treatment is shown in Table 3-2. The results are from jar tests us ing fresh MIEX-Na resin that was regenerated with sodium chloride. A linear regression line was fit to the resin dose and hardness removal data ( R2 = 0.997), and showed that 3.6% hardness re moval is achieved per mL/L of MIEXNa resin. Furthermore, MIEX-Na resin remo ved 0.40 meq of hardness per meq of resin at 16 mL/L, which means that the resin wa s 40% saturated with calcium. Complete removal of hardness from Cedar Key water at 16 mL/L MIEX-Na resin is equal to 66% of the cation exchange sites occupied with ca lcium. Thus, the resin has sufficient cation exchange capacity to remove all hardness at 16 mL/L MIEX-Na resin. The previous

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26 calculations used a MIEX-Na resin capacit y of 0.52 meq/mL, and assumed that 20 min was sufficient time for ion exchange. T he resin capacity is a reasonable assumption based on previous work using MIEX-Cl (Boyer and Singer, 2008). The mixing time is also reasonable for an inorganic cation exchange reaction (Kunin and Barry, 1949). Weak-acid cation exchange resin in the sodi um-form has been previously reported to have a high affinity for calcium (Kunin and Barry, 1949), so the exce ss cation exchange capacity remaining after treatment suggests that MIEX-Na resin was incompletely converted to the sodium form. Moreover, weak-acid resin in the hydrogen-form has a very low affinity for sodium and calcium (K unin and Barry, 1949). Therefore, incomplete conversion of magnetic cation exchange resin to the sodium-form is a likely explanation for the hardness removal results. Table 3-2 shows that MIEX-Na resin also removed UV-absorbing substances and DOC. This is surprising because DOM is rich in carboxylic acid functional groups, which give DOM a net negative charge over the pH range of natural waters (Ritchie and Perdue, 2003) and allow DOM to take part in anion exchange reactions (Boyer et al., 2008). The increase in chloride suggests t he possibility of anion exchange between DOM and resin-phase chloride. Because MIEX-Na resin is synthesized from the same starting material as MIEX-Cl resin it is po ssible that there are residual anion exchange functional groups on the cation exchange resin. However, the sulf ate results do not support the anion exchange hypothesis and sugges t that the chloride release is an artifact of regenerating the resi n in sodium chloride solution. Alternative explanations for DOM removal by cation exchan ge resin include adsorption of DOM to the resin matrix and cation exchange uptake of DOM-Ca+ complexes. Boyer and Singer (2008)

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27 previously showed no removal of DOC by a weak-acid, magnet ic cation exchange resin, so adsorption is unlikely. The fraction of DOM that is complexed with calcium (i.e., [DOM-Ca+]/[DOM]) can be estimated using the wo rk of Lin et al. (2005), where DOMCa+ is formed by binding of calcium and carbox ylic acid groups of DOM (Kalinichev and Kirkpatrick, 2007). Assuming that the total hardness (274.5 mg/L as CaCO3) is as calcium (2.74510-3 M Ca2+) and using the stability constant for Suwannee River fulvic acid ( Ks = 50 M-1), [DOM-Ca+]/[DOM] = Ks[Ca2+] = 0.14. The previous calculation supports the idea that a fraction of DOM is removable by cation exchange resin. Cation exchange uptake of DOM-Ca+ is further supported by re sults for Amberlite 200 cation exchange resin shown in Table 3-2. Amber lite 200 shows substantial removal of hardness and no removal of UV254, DOC, chloride, or sulfat e. The polystyrene matrix of Amberlite 200C allows transport of calcium but hinders the transport of DOM and DOMCa+ (Boyer and Singer, 2008). Thus, ca tion exchange uptake of DOM-Ca+ is a reasonable explanation for DOM re moval by MIEX-Na resin. All subsequent cation exchange jar tests were conducted using 16 mL/L MIEX-Na resin, because this resin dose achieved greater than 50% hardness removal. The impact of the regenerati on procedure on the efficien cy of hardness removal by MIEX-Na resin was also investigated. T he MIEX-Na resin was regenerated using a brine solution and an acid/base solution. Figure 3-3 shows the effect of the regeneration procedure on hardness removal. Regeneration of MIEX-Na resin with brine solution results in a measureable advantage in hardn ess removal as compared with acid/base regeneration for the fresh resi n test conditions. During the acid/base procedure, the milliequivalents of sodium added to solution was equal to 1 times the resin capacity,

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28 while the brine regeneration was conducted with 25 times more sodium than resin. The subsequent regeneration test results show that the regeneration procedure had a dramatic impact on hardness removal. Fo r example, hardness removal by resin regenerated with brine decreased from 66% for the fresh resin to 52% for the regenerated resins (i.e., regen. 1 and 2). In contrast, hardness removal by resin regenerated with acid/base soluti on decreased from 51% for the fresh resin to <10% for the regenerated resins (regen. 1 and 2). T he difference in hardness removal due to the brine and acid/base regenerat ion procedures is a result of the affinity of the carboxylic acid functional groups for hy drogen, sodium, and calcium (Kunin and Barry (1949)). Thus, the acid/base regeneration procedure was found to be ineffective at regenerating the resin. All subsequent regenerations were conducted using the brine regeneration procedure. Combined Cation and Anion Exchange Treatment MIEX-Na and MIEX-Cl resins were used s eparately and combined to treat Cedar Key water, and removal of DOC, UV254, and hardness was measured as shown in Figure 3-4. The doses of 2 mL/L of MIEXCl resin and 16 mL/L MIEX-Na resin were used for all jar tests. All results are fo r ion exchange resin that has gone through three regeneration cycles, which will be discussed in more detail in following sections. As seen previously, MIEX-Na resin removed 54% of hardness and removed 19% and 21% of DOC and UV254, respectively. MIEX-Cl resin remov ed a substantial amount of DOM (76% DOC and 89% UV254) and a small fraction of hardness. When MIEX-Na and MIEX-Cl resins were combined, hardness re moval was approximately equal to cation exchange treatment al one, while DOC and UV254 removal was approximately equal to anion exchange treatment alone. Thus, removal of hardness and DOM was not

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29 cumulative for combined anion and cation exchange treatment. Hardness removal is explained by DOM-Ca+ representing a small fraction of total calcium, while DOM removal is explained by DOM-Ca+ retaining deprotonated carboxylic acid groups in the presence of calcium (Bose and Reckhow (1997 )). It is important to emphasize that combined anion and cation exchange treatment is an effective strategy whereby a single unit process can remove 71% DOC and 58% hardness, as can be seen in Figure 3-4. The Cedar Key Water & Sewer District uses the following treatment train: permanganate oxidation at t he well head; MIEX-Cl to remove DOM; lime softening to remove hardness; sand filtration; and chlo rine disinfection. Table 3-3 shows a comparison of water quality data from laboratory-scale, combined ion exchange treatment and full-scale treatment. The comb ined ion exchange process produces water that has a finished water quality near drinking water standards. Simultaneous Versus Sequential Co mbined Ion Exchange Treatment Sequential cation and anion exchange treat ment was tested and compared with simultaneous ion exchange treatment, which was the focus of the previous section. The basis for sequential ion exchange was to ma ximize the removal of hardness and DOM as would be achieved by the summation of hardness and DOM removal by individual cation and anion exchange in Figure 3-4. Fi gures 3-5(a–c) show the removal of hardness, DOC, and UV254 as a function of the ion exchange treatment scenario and number of regeneration cycles. For fres h resin, removal of DOC and UV254 was consistently greater for sequential ion exchange (bot h Sequences 1 and 2) as compared with simultaneous ion exchange, but hardness removal was greater for simultaneous treatment. Furt hermore, there was little difference in hardness and DOM

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30 removal for Sequences 1 and 2. These resu lts support the assert ion that separate cation and anion exchange treatment, using fresh re sin, achieves cumulative removal of hardness and DOM as would be expected from t he results in Figure 3-4. However, the results show there is only a slight cu mulative effect otherwise nearly 100% DOC removal would have been seen by the third regener ation cycle. Evaluating the performance of ion exc hange resin over multiple regeneration cycles is an important contribution of this work, because previous studies have focused on testing fresh resin or simulating c ontinuous operation (Me rgen et al., (2008) and references therein). This is the first study to comprehensively investigate the regeneration of MIEX resin on a batch tr eatment basis. The importance of the regeneration process is illustrated in com paring the removal of hardness and DOM as a function of the number of r egeneration cycles. For example, removal of hardness, DOC, and UV254 all individually approa ched similar values for the three ion exchange treatment scenarios after three regeneration cycles. A different conclusion would have been reached if only fresh resin was evaluated. Although the effect of t he ion exchange treatment scenario was moderated by multiple regeneration cycles, the behavior of hardness and DOM differed over the course of the regeneration proc ess. For example, over the course of three regeneration cycles total hardness removal decreased by 9% for Sequences 1 and 2, whereas hardness removal, after an initial drop in remo val, increased over the course of the three regeneration cycles for simultaneous treatm ent. It is not clear why the multiple regeneration cycles affected hardness removal by Sequences 1 and 2. In contrast to hardness removal, DOC and UV254 removal tended to increase for the three ion

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31 exchange treatment scenarios over the course of three regeneration cycles. Furthermore, UV254 removal increased by a greater extent than DOC removal as indicated by SUVA254. For fresh resin, SUVA254 values for Simultaneous, Sequence 1, and Sequence 2 treated samples were 2.3, 2.1, and 2.1 L/mgCm, respectively. Following three regeneration cycles, SUVA254 values for Simultaneous, Sequence 1, and Sequence 2 treated samples were 1.7, 1.8, and 1.6 L/mgCm, respectively. Increased DOM removal upon regeneration was unexpected, because the fresh resin was regenerated before it was used to ensur e that it had full anion exchange capacity. Thus, it is not clear why removal of hardness and DOM follow different trends with respect to the ion exchange treatment sc enario and number of regeneration cycles. Sulfate and TN were also analyzed to study simultaneous versus sequential ion exchange treatment. Sulf ate removal averaged 82% for Simultaneous, Sequence 1, and Sequence 2 for fresh resi n and regenerated resin. Similarly, TN removal was independent of the i on exchange treatment scenario and regeneration cycle, and removal averaged 30%. The TN removed is believed to be part of the DOM that was removed, because nitrate was < 0.01 mg N/L in the raw water. Greater removal of DOC relative to TN has been reported previously for MIEX-Cl resin (Boyer et al., 2008). The overall order of treatment efficiency for combined ion exchange treatment, considering both simultaneous and sequential treatment for fresh and regener ated resin, was UV254 ~ sulfate > DOC > hardness > TN. Fluorescence EEMs were analyzed to help understand the differences in hardness and DOM removal by anion and cation exch ange. Figure 3-6 shows fluorescence EEMs for Cedar Key raw water, anion exchange tr eated water, and cation exchange treated

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32 water, and the corresponding DOC and hardne ss concentrations. The EEM for Cedar Key water had three peaks: Peak 1 at EM = 440 nm and EX = 265 nm Peak 2 at EM = 300 nm and EX = 275 nm, and Peak 3 at EM = 300 nm and EX = 230 nm. Peak 1 is attributed to terrestrially derived DOM, wh ile Peaks 2 and 3 are likely attributed to microbially derived DOM (Coble, 1996; Chen et al., 2003). Al though it is not known to what extent DOM-Ca+ complexes are contributing to the fluorescence EEM spectra, previous researchers have shown that DO M-metal complexes affect fluorescence intensity (Ohno et al., 2008; Yamashita and Jaffe, 2008). Raw water collected from Cedar Key consistently showed these three peaks as can be seen in Appendix F. Anion exchange treatment substantially decr eased all fluorescence peaks, with a corresponding decrease in DOC of 5.4 to 1. 3 mg C/ L. In contrast, cation exchange treatment only decreased fluorescence Peak s 2 and 3, with corres ponding decrease in DOC of 5.4 to 4.7 mg C/L. Thus, the cation exch ange resin appears to selectively remove microbially derived DOM fluorophores which may also correspond to DOM that preferentially binds calcium. Influence of Regeneration Para meters on Removal Efficiency It was shown that regenerat ion with brine was more effective than regeneration with an acid/base solution. As a result, t he impact of the meq NaCl/meq MIEX resin ratio, regeneration time, and regeneration soluti on chemistry were investigated to learn more about the brine regeneratio n process. Hardness removal as a function of sodium chloride concentration in the regeneration so lution is shown in Figure 3-7, where 25 meq NaCl/meq MIEX-Na resin is the base line regeneration concentration. The data correspond to treatment with 16 mL/L MIEXNa resin after one regeneration cycle. There is a clear trend of in creasing hardness removal with increasing concentration of

PAGE 33

33 sodium chloride in the regeneration solu tion. At a regeneration level of 50 meq NaCl/meq MIEX-Na resin, hardness re moval approached 70%, and the theoretical saturation of the resin with calcium and magnesium was 44% (compared to 36% for baseline regeneration). This suggests that more resin capacity would be available if the resin was regenerated in a brine solution wi th a regeneration ratio greater than 50 meq NaCl/meq MIEX Na resin. In Figure 3-8, the reaction time and r egeneration time are varied to measure the effects on hardness removal. The reaction time is defined as the length of time fresh resin is mixed in raw water, while the regener ation time is the length of time exhausted resin is mixed in concentrated sodium chlo ride solution. The results show that the exchange of hardness ions with sodi um ions can take place wi thin five minutes in the raw water and the regeneration solution. Alt hough these results show that the cation exchange process is relatively quick, longer reaction time s are needed to transfer DOM to/from the anion exchange resi n in a combined ion exchange treatment process (Boyer and Singer, 2005). All regeneration experiment s, up to this point, were conducted using regeneration solution prepared with DI water that c ontained negligible am ounts of hardness and alkalinity. At a full-scale water treatment plant, how ever, chemical reagents are prepared with finished drinking water that ma y contain measurable inorganic chemicals. Thus, a set of regeneration experiments we re conducted to compare hardness removal using regeneration solutions pr epared from DI water and t ap water. The tap water was from Gainesville, FL and had a hardness of 146 mg/L as CaCO3 and an alkalinity of 42 mg/L as CaCO3. The combined ion exchange resins were regenerated using a tap

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34 water regeneration solution fo llowing the baselin e procedure. Table 3-4 shows that hardness removal by 16 mL/L of fresh MIEXNa resin was approximately equal for DI water and tap water regeneration solutions. Th is means that hardness cations present in the tap water had little to no effect on t he regeneration process. In addition, removal of UV254-absorbing substances was consistent regar dless of the use of DI or tap water to prepare the regeneration solution. The impact of reusing t he regeneration solution was al so investigated. Hardness removal decreased by an average of 14% after each regeneration cycle with “used” regeneration solution for both DI water and tap water, as shown in Table 3-4. Before the last regeneration, ~2,563 mg/L (48.4 meq/L) of sodium carbonate was added to the tap water regeneration solution. This am ount corresponded to the theoretical milliequivalents of hardness cations added to the “used” regeneration solution during the previous regeneration cycles, based on calc ulations. A precipit ate was immediately formed by addition of sodium carbonate to the used regeneration solution. The precipitate was not characterized, but it was likely a calcium carbonate mineral. The regeneration solution was then f iltered through a 1.6 m GF /A filter (Whatman) to remove the precipitate. The resin was r egenerated using the sodi um carbonate treated solution and tested in a jar test. The har dness removal increased by 13% from the previous jar test. This suggests that the r egeneration solution can be more effectively reused if calcium is precipitated out of soluti on, especially if a sodium salt of carbonate is used. Furthermore, calcium sulfate may precipitate during r egeneration of combined ion exchange resin, which would benefit both anion and cation exchange regeneration. Thus, the regeneration efficiency of combi ned ion exchange resin can be increased by

PAGE 35

35 the addition of sodium or the removal of calcium from the r egeneration solution; however, increasing resin contact time with the regeneration solution or raw water has no effect. An experiment to determine the regeneration efficiency and resin utilization over a range of meq NaCl to meq MIEX-Na resin eq uivalence ratios was conducted. Figure 3-9 shows that regeneration efficiency increas es as the equivalence ratio decreases meaning that a higher percentage of the sodium is transfe rred to the resin at lower equivalence ratios. However, the amount of calcium removed from the resin increases as the equivalence ratio increases up to an equivalence ratio of 100. Therefore, the desired balanced between sodium chloride usage and resin regeneration efficiency must be chosen by the water treatment plant. Applications of Combined Ion Exchange Treatment Previous researchers have separately investigated anion and cation exchange treatment and shown these processes to be a possible pre-treat ment for membrane systems to reduce fouling (Fabr is et al., 2007; Heijman et al., 2009). However, the impact of combined anion and cation ex change treatment on the reduction of membrane fouling has not been previously demonstrated. Figure 3-10 shows the theoretical reduction in membrane fouling as a result of preventi on of calcium sulfate precipitation and removal of DOM, both of which are major foulants of membrane systems (Shih et al., 2005; Lin et al., 2006; Ja rusutthirak et al., 2007). Although chloride and sodium are added to the ion exchange treat ed water, Jarusutthirak et al. (2007) showed that these monovalent ions cause le ss flux decline than the divalent ions of sulfate, carbonate, and calcium. The membr ane fouling potentials were calculated as: inorganic fouling potential = {[Ca2+][SO4 2-]}/{[Ca2+]0[SO4 2-]0} and organic fouling potential

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36 = [DOC]/[DOC]0, where the subscript 0 indicates in itial concentration. The ion exchange treatment scenarios are as follows: Cation = 16 mL/L MIEX-Na resin, Anion = 2 mL/L MIEX-Cl resin, and Cation + Anion = 16 mL /L MIEX-Na and 2 mL/L MIEX-Cl resins. Although individual cation and anion exchange treatment can reduce the fouling potential, the largest reducti on in fouling is achieved with combined ion exchange treatment. It is expected that combined ion exchange treatment will be effective for reducing membrane fouling potential for a wide range of DOM, sulfate, and calcium concentrations. Table 3-1. Characteristic of Cedar Key raw water used in ion exchange experiments Parameter Average Minimum Maximum pH 7.58 7.09 8.06 UV254 (cm-1) 0.171 0.168 0.186 DOC (mg C/L) 5.6 5.0 6.1 TN (mg N/L) 0.32 0.25 0.38 Cl(mg/L) 11.8 10.5 14.3 SO4 2(mg/L) 20.9 16.9 31.5 Hardness (mg/L CaCO3) 274.5 264.5 287.5 Alkalinity (mg/L CaCO3) 244a Calcium (mg/L) 103a aBased on one measurement from January 2009 water; other cations (mg/L): Na+ = 5.49, K+ = 0.38, Mg2+ = 4.18, Sr2+ = 0.87.

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37 Table 3-2. Preliminary jar test results for fresh MIEX-Na resin MIEX-Na (mL/L) Hardness UV254 DOC Chloride Sulfate 2 b 7.7 1.6 3.3 -0.4 0.1 4 b 12.3 3.2 4.4 -2.6 -2.6 16c 57.4 0 16.0 0 6.7 3. 5 -8.7 5.0 3.8 0.1 Amberlite 200Cc, d 76.5 0 -1.1 0.8 -2.3 1.2 -1.0 0.1 -1.2 0.3 a All results are percent removal. b Single resin dose. c Duplicate resin dose; average value one standard deviation reported. d Jar test experiment wit h resin dose of 8 mL/L. Table 3-3. Comparison of finished water qua lity for combined ion exchange and municipal drinking water Parameter Combined ion exchangeaMunicipal drinking water b pH 7.70 8.08 DOC (mg C/L) 1.70 1.1 Hardness (mg/L as CaCO3) 111.6 172.8 Chloride (mg/L) 48.8 59.7 Sulfate (mg/L) 3.1 1.1 a Cation + Anion in Figure 2. b Cedar Key Water & Sewer District; August 2009. Table 3-4. Comparison of regeneration solu tions prepared from DI water and tap water Hardness removal Regeneration solution DI waterTap wateraFresh regeneration so lution 58% 62% Reused regeneration solution (1)44% 45% Reused regeneration solution (2)33% Na2CO3 added to reused solution 46% a Experiments with tap water we re 1 L, single jar tests.

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Figure 3 Figure 3 0 % 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % 90 % 100 % Removal 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%Removal 3 -1. Prelimi n before fi r 3 -2. Comp a prior reg e % % % % % % % % % % % 0.5 mL / U V D O T N S U S u n ary result s r st use. rison of su l e neration. / L1 mL / Te s V 254 O C N U V A u lfate (mg/L) s for MIEXl fate and D / L2 m L s t Condition s Constitue n 38 Cl resin co OC remov a L /L2 m Regen e s DOC (m g n t 2 mL/ 2 mL/ mpared wi t a l by MIEX 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 L/L e rated g C/L) L L Regenerat e t h MIEX-Cl Cl resin wi SUVA (L/mg C/m) e d regenerat e th and wit h e d h out

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Figure 3 Figure 3 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%Removal 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%Removal 3 -3. Impact removal 3 -4. Comp a ion exch a after thr e Fresh Re Catio n DOC UV254 Hardnes s of brine an by magnet rison of D O a nge treat m e e regener a sinR e Test C n A Ion Exc h s d acid/bas e ic cation e x O M and ha r m ent using a tion cycle s e gen. 1x C onditions Bri n A ci d A nion h ange Treat m 39 e regenera t x change us r dness rem 2 mL/L MI E s Regen. 2 x n e d /Base Simultaneo u m ent t ion proce d ing 16 mL/ oval by cat E X-Cl and 1 x u s d ures on h a L MIEX-N a ion, anion, 1 6 mL/L MI a rdness a resin. and combi EX-Na res i ned i ns

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Figure 3 3 -5. Comp a removal MIEX-N a rison of si m of (a) hard n a resin and m ultaneous n ess, (b) D 2 mL/L MI E 40 and sequ e OC, and ( c E X-Cl resi n e ntial ion e x c ) UV254. Al l n x change tr e l jar tests u s e atment on s ed 16 mL / / L

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Figure 3 3 -5. Contin u u ed. 41

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42 Figure 3-6. Fluorescence EEMs for (a) Cedar Key water (5.4 mg C/L, 277 mg/L as CaCO3), (b) MIEX-Cl treatment (1.3 mg C/L, 273 mg/L as CaCO3), and (c) MIEX-Na treatment (4.7 mg C/L, 120 mg/L as CaCO3). (a) (b) (c)

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Figure 3 Figure 3 0 % 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % 90 % 100 % Hardness Removal 0 % 10 % 20 % 30 % 40 % 50 % 60 % 70 % 80 % 90 % 100 % Hardness Removal 3 -7. Effect o hardnes s 3 -8. Effect o efficienc y % % % % % % % % % % % 10 m e 25 m e 50 m e % % % % % % % % % % % 010 o f the ratio o s removal. o f varying r e y and hard n Simultane o e q NaCl/ me q e q NaCl/ me q e q NaCl/ me q 20 Ti m o f NaCl to M e action tim e n ess remo v o us Ion Exc h q MIEX-Na q MIEX-Na q MIEX-Na 3040 m e (minutes) Reaction Ti Regenerati o Reaction Ti Regenerati o 43 M IEX-Na r e e and rege n v al by MIE X h ange 50 me = x-axis o n Time = 30 me = 20 min o n Time = xa e sin on reg e n eration ti m X -Na resin. 6070 min a xis e neration e m e on rege n e fficiency a n n eration n d

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Figure 3 Figure 3 Regeneration Efficiency (% Sodium Transferred to Resin) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1Membrane Fouling Potential 3 -9. Regen e used d 3 -10. Theo r calcium s 0.0% 1.0% 2.0% 3.0% 4.0% 5.0% 6.0% 7.0% 8.0% 9.0% 0 Cation I o e ration effi c uring rege n r etical redu c s ulfate pre c 5 A ni o o n Exchang e c iency and n eration. c tion in fou l c ipitation. 0 Equ i o nSim u e Treatment 44 resin utiliz a l ing cause d 100 i valence Rat u ltaneous CaSO4 DOC a tion based d by dissol v R 150 io Regenera t Resin Utili on the eq u v ed organic R = 0.982 6 R = 0.9355 t ion Efficienc y zation u ivalence r a matter an d 6 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 200 ResinUtilization y a tio d Resin Utilization (meq Calcium / meq MIEX)

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45 CHAPTER 4 CONCLUSIONS Conclusions The overall goal of this work was to evaluate combined anion and cation exchange treatment for removal of DOM and hardness. The major conclusions of this work are summarized as follows: Anion and cation exchange resins can be used in a single completely mixed reactor to remove DOM (>70% DOC) and hardnes s (>50% hardness) simultaneously. This allows for the most efficient use of the brine regeneration solution. Although sequential tr eatment showed slightly better removal for fresh resin, the differences between sequential and simult aneous treatment were dampened by the third regeneration cycle. The behavior of the MIEX-Cl and MIEX-Na re sin changed with regeneration prior to first use and over the regeneration cycles. Increasing the ratio of meq Na+/meq MIEX-Na resin from 10 to 50 resulted in increased hardness removal. However, increasing the ratio of meq Cl-/meq MIEX-Cl resin from 25 to 200 did not improve DOC or UV254 removal. A higher percentage of sodium in the regener ation solution is transferred to the MIEX-Na resin as the meq Na+/meq MIEX-Na ratio decreases; however, the meq of calcium removed decreases as the meq Na+/meq MIEX-Na ratio decreases. The regeneration solution can be used repea tedly, especially if hardness cations are precipitated out of soluti on. Precipitation may also be used to precipitate anions such as sulfate. An economic analysi s should be conducted to determine if precipitation of inorganic co mpounds or the use of a new NaCl solution is more feasible. Tap water, which contained measureable hardness and alkalinity, provided the same regeneration efficiency as hardness-free, DI water. Recommendations for Further Research The results from MIEX-Na tests showed variability in hardness removal under the same test conditions. This suggests that the batches of MIEX-Na resin can have varying resin capacities. The capacity of each batch should be determined in order

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46 to obtain normalized results and to test t he assumption that the average capacity is 0.52 meq/mL resin. Combined MIEX resin should be regenerat ed at varying meq NaCl/meq MIEX-Na ratio based on molarity instead of volume of a 2 M solution. This would determine if the molarity of the solution a ffects the regeneration process. The treatment process presented here s hould be tried with more traditional ion exchange resins such as the Amberlite series.

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47 APPENDIX A PRELIMINARY EXPERIMENTAL WORK RESULTS Table A-1. Hardness results for preliminary experimental work Hardness Experiment Conc. C/Co % Rem. St. Dev. St. Dev./Co 0.5 mL/L M-Cl 266.7 1.000 0.0% 1 mL/L M-Cl 266.7 1.000 0.0% 2 mL/L M-Cl 262.5 0.984 1.6% Raw 266.7 0.5 mL/L M-Na 1 mL/L M-Na 2 mL/L M-Na 250 0.923 7.7% 4 mL/L M-Na 237.5 0.877 12.3% Raw 270.8 16 mL/L M-Na 120.8 0.426 57.4% 0.000 0.000 8 mL/L AL-Na 66.7 0.235 76.5% 0.000 0.000 Raw 283.3 16 mL/L M-Na (Acid/Base) 141.7 0.531 46.9% 0.000 0.000 Control 267.7 1.004 -0.4% 0.035 0.006 Simultaneous 112.5 0.422 57.8% 0.000 0.000 Raw 266.7 Sequence 1 108.3 0.377 62.3% 0.141 0.020 Sequence 2 114.6 0.399 60.1% 0.071 0.010 Raw 287.5

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48 Table A-2. Dissolved organic carbon and total nitr ogen results for prelimi nary experimental work Dissolved Organic Carbon Total Nitrogen Experiment Conc. (mg/L C) C/Co % Rem. St. Dev. St. Dev./Co Conc. (mg/L C) C/Co % Rem. St. Dev. St. Dev./Co 0.5 mL/L M-Cl 4.48 0.83516.5% 0.069 0.013 0.259 0.879 12.1% 0.000 0.000 1 mL/L M-Cl 3.86 0.71928.1% 0.153 0.028 0.233 0.791 20.9% 0.000 0.000 2 mL/L M-Cl 2.52 0.46953.1% 0.144 0.027 0.208 0.707 29.3% 0.020 0.044 Raw 5.37 0.294 0.5 mL/L M-Na 5.69 0.9623.8% 0.311 1.087 -8.7% 1 mL/L M-Na 5.59 0.9455.5% 0.301 1.052 -5.2% Raw 5.92 0.286 2 mL/L M-Na 5.63 0.9356.5% 0.415 0.069 0.300 1.012 -1.2% 0.010 0.033 4 mL/L M-Na 5.45 0.9069.4% 0.560 0.093 0.305 1.013 -1.3% 0.004 0.012 Raw 6.02 0.144 0.304 0.025 16 mL/L M-Na 5.40 0.9336.7% 0.201 0.035 0.328 0.992 0.8% 0.015 0.045 8 mL/L Amberlite-Na 5.92 1.023-2.3% 0. 067 0.012 0.216 0.653 34.7% 0.004 0.013 Raw 5.79 0.330 16 mL/L M-Na (Acid/Base) 5.37 0.9208.0% 0.153 0.026 0.362 0.997 0.3% 0.045 0.125 Control 5.94 1.018-1.8% 0.109 0.019 0.367 1.011 -1.1% 0.032 0.089 Simultaneous 2.30 0.39560.5% 0.303 0. 052 0.341 0.939 6.1% 0.086 0.238 Raw 5.83 0.363 Sequence 1 2.02 0.36263.8% 0.107 0. 019 0.235 0.782 21.8% 0.017 0.058 Sequence 1 Midpoint (M-Cl) 2.21 0.395 60.5% 0.241 0.803 19.7% Sequence 2 2.11 0.37862.2% 0.126 0. 023 0.233 0.775 22.5% 0.013 0.044 Sequence 2 Midpoint (M-Na) 4.83 0.86513. 5% 0.322 1.073 -7.3% Raw 5.58 0.300

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49 Table A-3. UV254 and SUVA results for pre liminary experimental work UV254 Experiment Conc. C/Co % Rem. St. Dev. St. Dev./Co SUVA 0.5 mL/L M-Cl 0.1440.776 22.4% 0.004 0.019 3.2 1 mL/L M-Cl 0.1180.638 36.2% 0.004 0.023 3.1 2 mL/L M-Cl 0.0740.397 60.3% 0.002 0.011 2.9 Raw 0.185 3.4 0.5 mL/L M-Na 0.1811.040 -4.0% 1 mL/L M-Na 0.1761.011 -1.1% 2 mL/L M-Na 0.1780.989 1.1% 0.01 0.041 3.2 4 mL/L M-Na 0.1760.978 2.2% 0.01 0.082 3.2 Raw 0.180 0.01 3.0 16 mL/L M-Na 0.1470.840 16.0% 0.000 0.000 2.7 8 mL/L AL-Na 0.1771.011 -1.1% 0.001 0.008 3.0 Raw 0.175 3.0 16 mL/L M-Na (Acid/Base) 0.145 0.843 15.7% 0.000 0.000 2.7 Control 0.1741.009 -0.9% 0.001 0.004 2.9 Simultaneous 0.0510.297 70.3% 0.007 0.041 2.2 Raw 0.172 2.9 Sequence 1 0.0440.259 74.1% 0.001 0.014 2.2 Sequence 1 Midpoint (M-Cl) 0.0510.304 69.6% 2.3 Sequence 2 0.1440.256 74.4% 0.001 0.028 2.0 Sequence 2 Midpoint (M-Na) 0. 1390.827 17.3% 2.9 Raw 0.168 3.0

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50 Table A-4. Chloride and sulfate result s for preliminary experimental work Chloride Sulfate Experiment Conc. (mg/L)C/Co% Rem. St. Dev. St. Dev./Co Conc. (mg/L)C/Co % Rem. St. Dev. St. Dev./Co 0.5 mL/L M-Cl 19.99 1.49 -49.3% 0.321 0.024 16.76 1.25 -25.2% 0.395 0.000 1 mL/L M-Cl 24.50 1.83 -83.0% 0.728 0.054 9.67 0.72 27.7% 0.607 0.000 2 mL/L M-Cl 36.99 2.76 -176.3% 1.103 0.082 4.38 0.33 67.3% 0.125 0.000 Raw 13.39 22.89 0.5 mL/L M-Na 10.84 0.84 16.0% 14.43 0.65 35.2% 1 mL/L M-Na 11.66 0.90 9.6% 17.79 0.80 20.1% Raw 12.90 22.28 2 mL/L M-Na 13.22 0.97 2.8% 1.592 0.117 24.27 0.94 5.5% 6.815 0.265 4 mL/L M-Na 13.28 0.98 2.3% 1.943 0.143 23.99 0.93 6.6% 8.296 0.323 Raw 13.59 0.979 25.69 4.834 16 mL/L M-Na 14.85 1.09 -8.7% 0.687 0.050 26.37 0.96 3.8% 0.022 0.001 8 mL/L Amberlite-Na 13.84 1.01 -1.4% 0. 020 0.001 27.71 1.01 -1.3% 0.071 0.003 Raw 13.66 27.39 16 mL/L M-Na (Acid/Base) 13.06 1.00 0.4% 0.193 21.237 21.24 0.97 3.5% 0.035 0.002 Simultaneous 38.53 2.94 -193.9% 0.701 0.053 6.59 0.30 70.1% 0.507 0.023 Control 13.17 1.00 -0.4% 0.018 0. 001 22.02 1.00 -0.1% 0.068 0.003 Raw 13.11 22.00 Sequence 1 40.69 2.85 -184.8% 0.019 0.001 9.48 0.30 69.9% 0.058 0.002 Sequence 1 Midpoint (M-Cl) 40.97 2.87 -186.7% 10.14 Sequence 2 41.90 2.93 -193.2% 0.083 0.006 9.91 0.31 68.5% 0.030 0.001 Sequence 2 Midpoint (M-Na) 14.47 1.01 -1.3% 30.00 0.95 Raw 14.29 31.48

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51 APPENDIX B HARDNESS RESULTS FOR EXPERIMENTAL WORK Table B-1. Hardness removal comparison of brine and acid/base regeneration for 16 mL/L MIEX-Na Hardness Experiment Conc. (mg/L CaCO3) C/Co % Rem. St. Dev. St. Dev./Co Brine 95.8 0.34 66.2% 0.000 0.000 Acid/Base 136.5 0.48 51.8% 0.035 0.005 Raw 283.3 Brine Regen. 1x 126.0 0. 47 52.7% 0.035 0.006 Acid/Base Regen. 1x 241.7 0.91 9.4% 0.000 0.000 Raw 266.7 Brine Regen. 2x 131.3 0. 48 52.3% 0.071 0.011 Acid/Base Regen. 2x 255.2 0.93 7.2% 0.035 0.005 Raw 275.0 Table B-2. Hardness removal of simultaneou s treatment using 16 mL/L MIEX-Na and (unregenerated) 2 mL/L MIEX-Cl and a dos e of 2 mL/L regenerated MIEX-Cl Hardness Experiment Conc. (mg/L CaCO3) C/Co % Rem. St. Dev. St. Dev./Co Simultaneous (Unregen. M-Cl) 116.7 0.41 58.8% 0.000 0.000 Raw 283.3 Simultaneous Regen 1x (Eq. Ratio = 10) 179.2 0.64 35.8% 0.000 0.000 Raw 279.2 Simultaneous Regen. 2x (Eq. Ratio = 25) 135.4 0.49 51.5% 0.071 0.011 Raw 279.2 Simultaneous Regen. 3x (Eq. Ratio = 25) 133.3 0.48 51.5% 0.000 0.000 Raw 275.0 Simultaneous Regen. 4x (Eq. Ratio = 25) 131.3 0.49 50.8% 0.071 0.011 Raw 266.7 2 mL/L M-Cl Regenerated 264.5 1.00 0.0% 0.000 0.000 Raw 264.5

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52 Table B-3. Hardness removal for sequentia l treatments using 16 mL/L MIEX-Na and (regenerated) 2 mL/L MIEX-Cl Hardness Experiment Conc. (mg/L CaCO3) C/Co % Rem. St. Dev. St. Dev./Co Sequence 1 90.9 0.34 66.2% 0.000 0.000 Sequence 2 97.1 0.36 63.8% 0.071 0.011 Raw 268.6 Sequence 1 Regen. 1x 109.5 0.41 59.2% 0.071 0.011 Sequence 2 Regen. 1x 111.6 0.42 58.5% 0.000 0.000 Raw 268.6 Sequence 1 Regen. 2x 118.8 0.43 57.1% 0.035 0.005 Sequence 1 Midpoint (M-Cl) 272.7 0.99 1.5% 0.000 0.000 Sequence 2 Regen. 2x 121.9 0.44 56.0% 0.071 0.011 Sequence 2 Midpoint (M-Na) 119.8 0.43 56.7% 0.000 0.000 Raw 276.9 Sequence 1 Regen. 3x 115.7 0.43 56.9% 0.000 0.000 Sequence 1 Midpoint (M-Cl) 260.3 0.97 3.1% 0.000 0.000 Sequence 2 Regen. 3x 121.9 0.45 54.6% 0.071 0.011 Sequence 2 Midpoint (M-Na) 124.0 0.46 53.8% 0.000 0.000 Raw 268.6 Table B-4. Hardness removal for simultaneous treatment using 16 mL/L MIEX-Na and 2 mL/L (regenerated) MIEX-Cl Hardness Experiment Conc. (mg/L CaCO3) C/Co % Rem. St. Dev. St. Dev./Co Simultaneous 73.3 0.27 73.1% 0.050 0.008 Raw 272.7 Simultaneous Regen. 1x 118.8 0.45 55.4% 0.035 0.005 Simultaneous (Eq. Ratio = 50) 83.7 0.31 68.6% 0.106 0.016 Raw 266.5 Simultaneous Regen. 2x 117.8 0.44 56.0% 0.000 0.000 Simultaneous (Regen. Time =60 min.) 117.8 0.44 56.0% 0.071 0.011 Raw 267.6 Simultaneous Regen. 3x 111.6 0.42 58.1% 0.000 0.000 Simultaneous (Regen. Time = 5 min.) 111.6 0.42 58.1% 0.000 0.000 Raw 266.5 Simultaneous Regen. 4x (Reused Regen. Solution) 149.8 0.56 44.2% 0.106 0.016 Raw 268.6

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53 Table B-5. Hardness removal for simultaneous treatment using 16 mL/L MIEX-Na and 2 mL/L (regenerated) MIEX-Cl with the r euse of a tap water regeneration solution (1 L singlet jar tests) Hardness Experiment Conc. (mg/L CaCO3) C/Co % Rem. Tapwater Regen. 103.3 0.38 62.1% Tapwater Regen. 1x 148.8 0.55 45.5% Tapwater Regen. 2x 181.8 0.67 33.3% Tapwater Regen. 3x (added 2,563 mg/L Na2CO3) 146.7 0.54 46.2% Raw 272.7 Regeneration Solution 785.1 Tapwater 148.8 Table B-6. Hardness removal ov er time for 16 mL/L MIEX-Na Hardness Experiment Conc. (mg/L CaCO3) C/Co % Rem. St. Dev. St. Dev./Co Mixing Time = 5 min. 110.4 0.40 60.4% 0.000 0.000 Mixing Time = 10 min. 109.4 0.39 60.8% 0.035 0.005 Mixing Time = 20 min. 104.2 0.37 62.7% 0.000 0.000 Mixing Time = 40 min. 108.3 0.39 61.2% 0.000 0.000 Raw 279.2

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54 APPENDIX C DOC AND TN RESULTS FO R EXPERIMENTAL WORK Table C-1. Organics removal comparison of bri ne and acid/base regeneratio n for 16 mL/L MIEX-Na Dissolved Organic Carbon Total Nitrogen Experiment Conc. C/Co % Rem. St. Dev. St. De v./Co Conc. C/Co% Rem. St. Dev. St. Dev./Co Brine 4.92 0.92 8.5% 0.15 0.03 0.29 1.12 -12.0% 0.02 0.08 Acid/Base 4.94 0.92 8.2% 0.20 0. 04 0.28 1.09 -9.0% 0.02 0.09 Raw 5.38 0.26 Brine Regen. 1x 4.77 0.88 12.2% 0.06 0.01 0.24 0.96 3.8% 0.01 0.02 Acid/Base Regen. 1x 5.00 0.92 7.9% 0. 05 0.01 0.27 1.07 -6.7% 0.01 0.05 Raw 5.43 0.25 Brine Regen. 2x 4.64 0.84 16.1% 0.13 0.02 0.28 0.93 6.5% 0.01 0.04 Acid/Base Regen. 2x 4.87 0.88 11.8% 0. 07 0.01 0.26 0.89 10.7% 0.01 0.02 Raw 5.53 0.29

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55 Table C-2. Organics removal of simu ltaneous treatment using 16 mL/L MIEXNa and (unregenerated) 2 mL/L MIEX-Cl and a dose of 2 mL/L regenerated MIEX-Cl Dissolved Organic Carbon Total Nitrogen Experiment Conc. C/Co % Rem. St. Dev. St. De v./Co Conc. C/Co% Rem. St. Dev. St. Dev./Co Simultaneous (Unregen. M-Cl) 2.65 0.49 51.1% 0.11 0.02 0.25 0.80 19.7% 0.02 0.07 Raw 5.41 0.31 Simultaneous Regen 1x (Eq. Ratio = 10) 3.49 0.59 40.6% 0.03 0.01 0. 49 1.46 -45.5% 0.01 0.03 Raw 5.88 0.34 Simultaneous Regen. 2x (Eq. Ratio = 25) 1.57 0.27 73.4% 0.13 0.02 0.21 0.72 27.9% 0.02 0.06 Raw 5.92 0.30 Simultaneous Regen. 3x (Eq. Ratio = 25) 1.44 0.25 75.3% 0.05 0.01 0.20 0.62 37.9% 0.02 0.06 Raw 5.80 0.31 Simultaneous Regen. 4x (Eq. Ratio = 25) 1.59 0.27 72.8% 0.05 0.01 0.23 0.79 21.4% 0.01 0.04 Raw 5.85 0.29 2 mL/L M-Cl Regenerated 1.39 0.24 75.6% 0.13 0.02 0.19 0.70 30.2% 0.02 0.08 Raw 5.68 0.28

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56 Table C-3. Organics removal for sequ ential treatments using 16 mL/L MIEX-Na and (regenerated) 2 mL/L MIEX-Cl Dissolved Organic Carbon Total Nitrogen Experiment Conc. C/Co % Rem. St. Dev. St. De v./Co Conc. C/Co% Rem. St. Dev. St. Dev./Co Sequence 1 1.87 0.35 65.0% 0.07 0.01 0.23 0.73 26.7% 0.01 0.02 Sequence 2 1.75 0.33 67.1% 0.14 0.03 0.23 0.71 28.8% 0.02 0.06 Raw 5.33 0.32 Sequence 1 Regen. 1x 1.69 0.30 70.0% 0.13 0.02 0. 40 1.30 -29.7% 0.03 0.08 Sequence 2 Regen. 1x 1.43 0.26 74.5% 0.12 0.02 0.20 0.64 35.7% 0.02 0.05 Raw 5.61 0.31 Sequence 1 Regen. 2x 1.38 0.26 74.5% 0.06 0.01 0.24 0.79 21.0% 0.01 0.04 Sequence 1 Midpoint (M-Cl) 1.27 0.24 76.4% 0.00 0.00 0.22 0.71 28.5% 0.01 0.03 Sequence 2 Regen. 2x 1.63 0.30 69.8% 0.31 0.06 0.19 0.62 38.0% 0.01 0.03 Sequence 2 Midpoint (M-Na) 4.70 0.87 13.0% 0.00 0.00 0. 35 1.15 -15.4% 0.01 0.02 Raw 5.40 0.30 Sequence 1 Regen. 3x 1.31 0.22 77.7% 0.13 0.02 0.19 0.67 33.0% 0.01 0.04 Sequence 1 Midpoint (M-Cl) 1.41 0.24 75.9% 0.20 0.03 0.19 0.67 33.0% 0.01 0.02 Sequence 2 Regen. 3x 1.32 0.23 77.4% 0.19 0.03 0.19 0.70 30.3% 0.01 0.02 Sequence 2 Midpoint (M-Na) 4.73 0.81 19.2% 0.00 0.00 0. 35 1.27 -26.9% 0.00 0.00 Raw 5.85 0.28

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57 Table C-4. Organics removal for simult aneous treatment using 16 mL/L MIEX -Na and 2 mL/L (regenerated) MIEX-Cl Dissolved Organic Carbon Total Nitrogen Experiment Conc. C/Co % Rem. St. Dev. St. De v./Co Conc. C/Co% Rem. St. Dev. St. Dev./Co Simultaneous 2.42 0.43 57.1% 0.15 0.03 0.23 0.69 30.8% 0.03 0.08 Raw 5.65 0.34 Simultaneous Regen. 1x 2.03 0.35 64.6% 0.11 0.02 0.22 0.71 29.3% 0.03 0.09 Simultaneous (Eq. Ratio = 50) 1.80 0.31 68.6% 0.04 0.01 0.20 0.64 36.4% 0.01 0.03 Raw 5.73 0.32 Simultaneous Regen. 2x 1.90 0.34 65.8% 0.10 0.02 0.24 0.75 25.0% 0.01 0.04 Simultaneous (Regen. Time =60 min.) 1.66 0.30 70.2% 0.20 0.04 0.23 0.70 29.8% 0.02 0.05 Raw 5.57 0.32 Simultaneous Regen. 3x 1.70 0.29 70.7% 0.07 0.01 0.23 0.71 28.9% 0.02 0.07 Simultaneous (Regen. Time = 5 min.) 1.85 0.32 68.2% 0.22 0.04 0.22 0.65 34.5% 0.01 0.04 Raw 5.80 0.33 Simultaneous Regen. 4x (Reused Regen. Solution) 1.52 0.28 72.1% 0.13 0.02 0.23 0.77 23.0% 0.03 0.11 Raw 5.43 0.29

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58 APPENDIX D UV254 AND SUVA RESULTS FOR EXPERIMENTAL WORK Table D-1. UV254 removal comparison of brine and ac id/base regeneration for 16 mL/L MIEX-Na UV254 Experiment Conc. (cm-1) C/Co % Rem. St. Dev. St. Dev./Co SUVA Brine 0.149 0.87 12.6% 0.001 0.004 3.0 Acid/Base 0.147 0.86 13.5% 0.000 0.000 3.0 Raw 0.170 3.2 Brine Regen. 1x 0.137 0. 80 20.2% 0.001 0.004 2.9 Acid/Base Regen. 1x 0.143 0. 83 16.7% 0.001 0.004 2.8 Raw 0.171 3.1 Brine Regen. 2x 0.135 0. 80 20.1% 0.000 0.000 2.9 Acid/Base Regen. 2x 0.143 0. 85 15.4% 0.000 0.000 2.9 Raw 0.169 3.1 Table D-2. UV254 removal of simultaneous treatm ent using 16 mL/L MIEX-Na and (unregenerated) 2 mL/L MIEX-Cl and a dos e of 2 mL/L regenerated MIEX-Cl UV254 Experiment Conc. (cm-1) C/Co % Rem. St. Dev. St. Dev./Co SUVA Simultaneous (Unregen. M-Cl) 0.070 0.41258.8% 0.001 0.008 2.7 Raw 0.170 3.1 Simultaneous Regen 1x (Eq. Ratio = 10) 0.028 0.16583.5% 0.000 0.000 0.8 Raw 0.170 2.9 Simultaneous Regen. 2x (Eq. Ratio = 25) 0.023 0.13186.9% 0.001 0.004 1.4 Raw 0.172 2.9 Simultaneous Regen. 3x (Eq. Ratio = 25) 0.021 0.12487.6% 0.000 0.000 1.5 Raw 0.170 2.9 Simultaneous Regen. 4x (Eq. Ratio = 25) 0.021 0.12487.6% 0.001 0.008 1.3 Raw 0.170 2.9 2 mL/L M-Cl Regenerated 0.022 0.12687.4% 0.001 0.004 1.5 Raw 0.170 3.0

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59 Table D-3. UV254 removal for sequential treatm ents using 16 mL/L MIEX-Na and (regenerated) 2 mL/L MIEX-Cl UV254 Experiment Conc. (cm-1) C/Co % Rem. St. Dev. St. Dev./Co SUVA Sequence 1 0.038 0.22 77.9% 0.001 0.004 2.0 Sequence 2 0.033 0.19 80.6% 0.001 0.008 1.9 Raw 0.170 3.2 Sequence 1 Regen. 1x 0.030 0.18 82.4% 0.000 0.000 1.8 Sequence 2 Regen. 1x 0.023 0.13 86.8% 0.001 0.004 1.6 Raw 0.170 3.0 Sequence 1 Regen. 2x 0.025 0.14 85.6% 0.002 0.012 1.8 Sequence 1 Midpoint (M-Cl) 0.021 0.12 87.6% 0.000 0.000 1.6 Sequence 2 Regen. 2x 0.022 0.13 87.1% 0.001 0.008 1.4 Sequence 2 Midpoint (M-Na) 0.137 0.81 19.4% 0.000 0.000 2.9 Raw 0.170 3.1 Sequence 1 Regen. 3x 0.021 0.12 87.6% 0.000 0.000 1.6 Sequence 1 Midpoint (M-Cl) 0.019 0.11 88.8% 0.000 0.000 1.3 Sequence 2 Regen. 3x 0.019 0.11 88.8% 0.000 0.000 1.4 Sequence 2 Midpoint (M-Na) 0.133 0.79 21.3% 0.000 0.000 2.8 Raw 0.169 2.9 Table D-4. UV254 removal for simultaneous treatm ent using 16 mL/L MIEX-Na and 2 mL/L (regenerated) MIEX-Cl UV254 Experiment Conc. (cm-1) C/Co% Rem. St. Dev. St. Dev./Co SUVA Simultaneous 0.056 0.33 67.2% 0.00 0.00 2.3 Raw 0.169 3.0 Simultaneous Regen. 1x 0.038 0.22 78.3% 0.00 0.01 1.9 Simultaneous (Eq. Ratio = 50) 0.038 0.22 78.0% 0.00 0.02 2.1 Raw 0.173 3.0 Simultaneous Regen. 2x 0.031 0.18 82.2% 0.00 0.00 1.6 Simultaneous ( Regen. Time =60 min.) 0.030 0.17 82.7% 0.00 0.01 1.8 Raw 0.171 3.1 Simultaneous Regen. 3x 0.029 0.17 83.0% 0.00 0.00 1.7 Simultaneous (Regen. Time = 5 min.) 0.030 0.17 82.7% 0.00 0.00 1.6 Raw 0.171 2.9 Simultaneous Regen. 4x (Reused Regen. Solution) 0.024 0.14 86.3% 0.00 0.00 1.6 Raw 0.172 3.2

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60 Table D-5. UV removal for simultaneous tr eatment using 16 mL/L MIEX-Na and 2 mL/L (regenerated) MIEX-Cl with the reuse of a tap water regeneration solution (1 L singlet jar tests) Hardness Experiment Conc. (cm-1) C/Co % Rem. Tapwater Regen. 0.026 0.15 84.9% Tapwater Regen. 1x 0.025 0.15 85.5% Tapwater Regen. 2x 0.022 0.13 87.2% Tapwater Regen. 3x (added 2,563 mg/L Na2CO3) 0.023 0.13 86.6% Raw 0.172 Regeneration Solution 2.689

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61 APPENDIX E CHLORIDE AND SULFATE RESULT S FOR EXPERIMENTAL WORK Table E-1. Chloride addition and sulfate removal comparison of brine and acid/bas e regeneration for 16 mL/L MIEX-Na Chloride Sulfate Experiment Conc. (mg/L) C/Co % Rem. St. Dev. St. Dev./Co Conc. (mg/L) C/Co % Rem. St. Dev. St. Dev./Co Brine 17.19 1.39 -39.3% 0.16 0. 01 25.66 0.98 2.2% 0.10 0.00 Acid/Base 12.52 1.01 -1.4% 0.15 0. 01 26.42 1.01 -0.6% 0.31 0.01 Raw 12.34 26.25 Brine Regen. 1x 13.11 1.25 -24.8% 0. 56 0.05 16.32 0.97 3.2% 0.14 0.01 Acid/Base Regen. 1x 10.85 1.03 -3.3% 0. 00 0.00 17.12 1.02 -1.5% 0.03 0.00 Raw 10.50 16.86 Brine Regen. 2x 12.83 1.14 -13.6% 0. 16 0.01 22.53 0.98 2.0% 0.04 0.00 Acid/Base Regen. 2x 11.69 1.04 -3.5% 0. 02 0.00 23.58 1.03 -2.6% 0.02 0.00 Raw 11.29 22.99

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62 Table E-2. Chloride addition and sulfate removal of simultaneous treatment using 16 mL/L MIEX-Na and (unregenerated) 2 mL/L MIEX-Cl and a dose of 2 mL/L regenerated MIEX-Cl Chloride Sulfate Experiment Conc. (mg/L) C/Co% Rem. St. Dev. St. Dev./Co Conc. (mg/L) C/Co% Rem. St. Dev. St. Dev./Co Simultaneous (Unregen. M-Cl) 43.64 3.87 -286.7% 0.71 0.06 6.31 0.28 72.1% 0.29 0.01 Raw 11.28 22.61 Simultaneous Regen 1x (Eq. Ratio = 10) 37.71 3.35 -234.9% 0.20 0.02 4.82 0.21 78.8% 0.02 0.00 Raw 11.26 22.69 Simultaneous Regen. 2x (Eq. Ratio = 25) 43.83 3.86 -286.5% 1.94 0.17 4.32 0.19 81.0% 0.17 0.01 Raw 11.34 22.67 Simultaneous Regen. 3x (Eq. Ratio = 25) 44.61 4.10 -310.3% 0.43 0.04 3.22 0.17 83.2% 0.09 0.00 Raw 10.87 19.19 Simultaneous Regen. 4x (Eq. Ratio = 25) 40.24 3.73 -273.0% 0.11 0.01 2.83 0.16 84.3% 0.00 0.00 Raw 10.79 18.00 2 mL/L M-Cl Regenerated 41.70 3.68 -267.8% 0.34 0.03 2.72 0.15 84.8% 0.10 0.01 Raw 11.34 17.94

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63 Table E-3. Chloride addition and sulfate removal for sequent ial treatments using 16 mL/L MIEX-Na and (regenerated) 2 mL/L MIEX-Cl Chloride Sulfate Experiment Conc. (mg/L) C/Co% Rem. St. Dev. St. Dev./Co Conc. (mg/L) C/Co% Rem. St. Dev. St. Dev./Co Sequence 1 41.35 3.61 -261.4% 0.45 0.04 2.86 0.16 83.7% 0.14 0.01 Sequence 2 43.13 3.77 -276.9% 0.36 0.03 3.02 0.17 82.7% 0.01 0.00 Raw 11.44 17.52 Sequence 1 Regen. 1x 45.25 3.86 -286.2% 0.03 0.00 3.07 0.17 82.9% 0.01 0.00 Sequence 2 Regen. 1x 45.23 3.86 -286.0% 0.02 0.00 3.03 0.17 83.1% 0.05 0.00 Raw 11.72 17.98 Sequence 1 Regen. 2x 46.37 3.90 -289.7% 0.23 0.02 2.92 0.16 83.9% 0.02 0.00 Sequence 1 Midpoint (MCl) 0.00 3.40 -240.4% 0.00 0.00 0.00 0.19 80.9% 0.00 0.00 Sequence 2 Regen. 2x 44.44 3.73 -273.5% 0.49 0.04 3.06 0.17 83.2% 0.04 0.00 Sequence 2 Midpoint (MNa) 0.00 1.23 -22.6% 0.00 0.00 0.00 0.92 7.5% 0.00 0.00 Raw 11.90 18.16 Sequence 1 Regen. 3x 46.13 3.78 -277.6% 0.55 0.05 2.92 0.15 84.6% 0.03 0.00 Sequence 1 Midpoint (MCl) 36.29 3.25 -224.7% 0.00 0.00 3.14 0.18 82.1% 0.00 0.00 Sequence 2 Regen. 3x 50.62 4.14 -314.4% 0.41 0.03 3.46 0.18 81.8% 0.03 0.00 Sequence 2 Midpoint (MNa) 19.68 1.76 -76.2% 0.00 0.00 16.29 0.93 7.4% 0.00 0.00 Raw 12.22 19.00

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64 Table E-4. Chloride addition and sulfate removal for si multaneous treatment using 16 mL/L MIEX-Na and 2 mL/L (regenerated) MIEX-Cl Chloride Sulfate Experiment Conc. (mg/L) C/Co% Rem. St. Dev. St. Dev./Co Conc. (mg/L) C/Co% Rem. St. Dev. St. Dev./Co Simultaneous 43.07 3.85 285.4% 0.19 0.03 4.07 0.23 76.6% 0.00 0.00 Raw 11.17 17.53 Simultaneous Regen. 1x 46.94 4.15 314.8% 3.06 0.27 3.44 0.19 80.8% 0.18 0.01 Simultaneous (Eq. Ratio = 50) 55.82 4.93 393.3% 3.00 0.27 3.67 0.21 79.4% 0.07 0.00 Raw 11.32 17.85 Simultaneous Regen. 2x 47.57 4.24 324.0% 0.24 0.02 3.06 0.17 82.6% 0.02 0.00 Simultaneous (Regen. Time =60 min.) 48.44 4.32 331.8% 0.51 0.05 3.02 0.17 82.8% 0.04 0.00 Raw 11.22 17.57 Simultaneous Regen. 3x 48.79 4.33 333.3% 0.03 0.00 3.11 0.18 82.3% 0.00 0.00 Simultaneous (Regen. Time = 5 min.) 43.94 3.90 -290.2% 0.08 0.01 3.09 0.18 82.4% 0.04 0.00 Raw 11.26 17.60 Simultaneous Regen. 4x (Reused Regen. Solution) 45.20 3.99 299.3% 0.73 0.06 3.06 0.17 82.7% 0.06 0.00 Raw 11.32 17.70

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65 APPENDIX F EEMS FOR SELECTED EXPERIMENTAL WORK Figure F-1. EEMs for (left) raw water and (r ight) 2 mL/L unregenerated MIEX-Cl treated water. Figure F-2. EEMs for (left) raw water, (center) 16 mL/L MIEX-Na treated water, and (right) 8 mL/L Amberlite-Na treated water.

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66 Figure F-3. EEMs for (left) raw water and simultaneous treat ment using 16 mL/L MIEX-Na and 2 mL/L unregenerated MIEX-Cl.

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67 Figure F-4. EEMs for (top left) raw water for (top right) si multaneous treatment using 16 mL/L MIEX-Na and 2 mL/L unregenerated MIEX-Cl and the (bottom left) raw water for (bottom right) 16 mL/L MIEX-Na and 2 mL/L MIEXCl that had been through four regeneration cycles.

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68 Figure F-5. EEMs for (left) raw water, (center) 16 mL/L MIEX-Na treated water, and (right) 2 mL/L MIEX-Cl treated water with resin that had been through two regeneration cycles. Figure F-6. EEMs for (left) raw water (r ight) for simultaneous treatment using 16 mL/L MIEX-Na and 2 mL/L MIEX-Cl that had been through two regeneration cycles.

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69 LIST OF REFERENCES American Public Health Association, Amer ican Water Works Association, and Water Environment Federation 1998. Standard Met hods for the Examination of Water and Wastewater, 20th Edition. Washington DC. Archer, A.D., Singer, P.C., 2006. An eval uation of the relationship between SUVA and NOM coagulation using the ICR databas e. Journal American Water Works Association 98(7), 110-123. Bose, P., Reckhow, D.A., 1997. Modeling pH and ionic strength effects on proton and calcium complexation of fulvic acid: A tool for drinking water-NOM studies. Environmental Science & Te chnology 31(3), 765-770. Boyer, T.H., Singer, P.C., 2005. Bench-scale testing of a magnetic ion exchange resin for removal of disinfection by-product precursors. Water Research 39, 12651276. Boyer, T. H., Singer, P.C., 2006. A pilotscale evaluation of magnetic ion exchange treatment for removal of natural or ganic material and inorganic anions. Water Research 40(15), 2865–2876. Boyer, T.H., Singer, P.C., 2008. Stoichiometr y of removal of natural organic matter by ion exchange. Environmental Sc ience & Technology 42, 608-613. Boyer, T.H., Singer, P.C., Ai ken, G.R., 2008. Removal of dissolved organic matter by anion exchange: Effect of dissolved or ganic matter properties. Environmental Science & Technol ogy 42, 7431-7437. Chen, W., Westerhoff, P., Leenheer, J.A., Booksh, K., 2003. Fluorescence excitation Emission matrix regional integration to quantify spectra for dissolved organic matter. Environmental Scienc e & Technology 37(24), 5701-5710. Clifford, D.A., 1999. Ion Exchange and Inorgani c Adsorption. In Water Quality and Treatment: A Handbook of Community Water Supplies. Edited by R.D. Letterman, McGraw-Hill Inc., New York, NY. Coble, P.G., 1996. Characterization of mari ne and terrestrial DOM in seawater using excitation emission matrix spectro scopy. Marine Chemistry 51(4), 325-346. Cohn, P.D., Cox, M., Berger, P.S., 1999. Health and Aethetic Aspects of Water Quality. In Water Quality and Treatment: A Handb ook of Community Water Supplies. Edited by R.D. Letterman, McGraw-Hill Inc., New York, NY. Cornelissen, E.R., Beerendonk, E.F., Nederlof, M.N., van der Hoek, J.P., Wessels, L.P., 2009. Fluidized ion exchange (FIX) to cont rol NOM fouling in ultrafiltration. Desalination 236, 334-341.

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70 Cory, R.M., McKnight, D.M., 2005. Fluore scence spectroscopy reveals ubiquitous presence of oxidized and reduced quinones in dissolved organic matter. Environmental Science & Technology 39, 8142–8149. Dempsey, B.A., Ganho, R. M., Omelia, C.R., 1984. T he Coagulation of Humic Substances by Means of Aluminum Salts. Journal American Water Works Association 76(4), 141-150. Fabris, R., Lee, E.K., Chow, C.W.K., Chen, V., Drikas, M., 2007. Pre-treatments to reduce fouling of low pressure microfiltration (MF) membranes. Journal of Membrane Sciences 289, 231-240. Gray, S.R., Ritchie, C.B., Tran T., Bolto, B. A., 2007. Effect of NO M characteristics and membrane type on microfiltration perform ance. Water Research 41, 3833-3841. Heijman, S.G.J., Guo, H., Li, S., van Dij k, J.C., Wessels, L.P., 2009. Zero liquid discharge: Heading for 99% recovery in nanofiltration and reverse osmosis. Desalination 236, 357-362. Humbert, H, Gallard, H., Suty, H., Crou, J.P., 2005. Performance of selected anion exchange resins for the treatment of a high DOC content surface water. Water Research 39, 1699-1708. Humbert, H., Gallard, H., Jacquemet, V., Cr ou, J.P., 2007. Combin ation of coagulation and ion exchange for the reduction of UF fouling properties of a high DOC content surface water. Water Research 41, 3803-3811. Jarvis, P., Mergen, M., Banks, J., Mcintosh, B., Parsons, S.A., Jefferson, B., 2008. Pilot scale comparison of enhanced coagulation with magnetic resin plus coagulation systems. Environmental Scienc e & Technology 42(4), 1276-1282. Jarusutthirak, C., Mattaraj, S., Jirarat ananon, R., 2007. Influence of inorganic scalants and natural organic matter on nanofiltrati on membrane fouling. Journal of Membrane Science 287, 138-145. Johnson, C.J., Singer, P.C., 2004. Impact of a magnetic i on exchange resin on ozone demand and bromate formation during drinki ng water treatment. Water Research 38, 3738-3750. Kabsch-Korbutowicz, M., Majewska-Nowak K., Winnicki, T., 2008. Water treatment using MIEX DOC/ultrafiltration pr ocess. Desalination 221, 338-344. Kimura, K., Hane, Y., Watanabe, Y., Amy, G., Ohkuma, N., 2004. Irreversible membrane fouling during ultr afiltration of surface water. Water Research 38, 3431-3441.

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71 Kitis, M., Harman, B.I., Yigit, N.O., Bey han, M., Nguyen, H., Adams, B., 2007. The removal of natural organic matter from selected Turkish source waters using magnetic ion exchange resin (MIEX). Reac tive & Functional Polymers 67, 14951504. Kalinichev, A.G., Kirkpatrick, R.J., 2007. Molecular dynamics simulation of cationic complexation with natural organic matter. European Journal of Soil Science 58(4), 909-917. Kunin, R., Barry, R.E., 1949. Carboxylic, weak acid type, cation exchange resin. Industrial and Engineering Chemistry 41(6), 1269–1272. Li, Q.L., Elimelech, M., 2004. Organic foulin g and chemical cleaning of nanofiltration membranes: Measurements and mechani sms. Environmental Science & Technology 38(17), 4683-4693. Lin, C.J., Shirazi, S., Rao, P., Agarwal, S., 2006. Effects of operational parameters on cake formation of CaSO4 in nanofiltra tion. Water Research 40, 806-816. Lin, Y.-P., Singer, P.C., Aik en, G.R., 2005. Inhibition of calc ite precipitation by natural organic material: kinetics, mechanism and thermodynamics. Environmental Science and Technology 39, 6420-6428. Mercer, K.L., Lin, Y.P., Singer, P.C., 2005. Enhancing calcium ca rbonate precipitation by heterogeneous nucleation during chemical softening. Journal American Water Works Association 97(12), 116-125. Mergen, M.R.D., Jefferson, B., Parsons, S. A., Jarvis, P., 2008. Magnetic ion-exchange resin treatment: Impact of water type and resin use. Water Research 42, 19771988. Ohno, T., Amirbahman, A. Bro, R., 2008. Parallel factor analysis of excitation-emission matrix fluorescence spectra of water sol uble soil organic matter as basis for the determination of conditional metal binding parameters. Environmental Science & Technology 42(1), 186-192. Ritchie, J.D., Perdue, E.M., 2003. Proton-binding study of standard and reference fulvic acids, humic acids, and natural organic matter. Geochimica et Cosmochimica Acta 67(1), 85-96. Saravia, F., Zwiener, C., Frimmel, F.H ., Boller, M., 2006. Interactions between membrane surface, dissolved organic substances and ions in submerged membrane filtration. De salination 192, 280-297. Shih, W.Y., Rrahardianto, A., Lee, R. W., Cohen, Y., 20 05. Morphometric characterization of calcium sulfate dehydr ate (gypsum) scale on reverse osmosis membranes. Journal of Membrane Science 252, 253-263.

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72 Singer, P.C., Bilyk K., 2002. Enhanced c oagulation using a magnetic ion exchange resin. Water Research 36, 4009-4022. Singer, P. C., Boyer, T., Holm quist, A., Morran, J., Bourke, M., 2009. Integrated analysis of NOM removal by magnetic ion ex change. Journal American Water Works Association 101(1), 65–73. Stumm, W., Morgan, J.J., 1996. Aquatic Chem istry, John Wiley & Sons, Inc., New York. Yamashita, Y., Jaffe, R., 2008. Characterizing the interactions between trace metals and dissolved organic matter using excitati on-emission matrix and parallel factor analysis. Environmental Scienc e & Technology 42(19), 7374-7379. Zhang, R., Vigneswaran, S., Ngo, H., N guyen, H., 2008. Fluidi zed bed magnetic ion exchange (MIEX) as pre-tr eatment process for a s ubmerged membrane reactor in wastewater treatment and r euse. Desalination 227, 85-93.

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73 BIOGRAPHICAL SKETCH Jennifer Nicole Apell was born in1985 in Ta mpa, Florida. She lived in the Tampa Bay area until her acceptance to the Universi ty of Florida and subsequent relocation to Gainesville. She graduated wit h her B.S. in environmen tal engineering sciences in December 2008. She earned the honors of su mma cum laude with her honors thesis A Critical Review of Low-Pressure Memb rane Fouling by Natural Organic Matter As a participant of the 4/1 program, she immediately started work on a Master of Engineering in environmental engi neering. Her focus was on water and wastewater treatment which was complimented by her thesis research on ion exchange for water treatment. She has since accepted a position wit h the engineering consulti ng firm CDM, Inc. at its headquarters in Cambridge, MA.