This item is only available as the following downloads:
1 EVALUATION OF ANION EXCHANGE AND A DSORPTION FOR N ATURAL O RGANIC M ATTER (NOM) PRETREA TMENT FROM TWO SURFA CE WATERS USING A TWO STAGE COUNTERCURRENT REACTOR By KATHERINE GRAF A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ENGINEERING UNIVERSITY OF FLORIDA 2013
2 2013 Katherine Graf
3 To my mom, Heidi ; dad, Bill ; and s ister, Rachel
4 ACKNOWLEDGMENTS I acknowledge my advisor, Dr. Boyer, for helping me realize what I can become and pushing me to produce the best version of work that I am capable of, my committee, Dr. Chadik and Dr. Mazyck for their valuable feedback, my research group for their help and company in the lab, Dr. David Cornwell and EE&T for funding, valuable guidance and help with sampling, my family for their support, especially Rachel for her uplifting spirits and large biceps for carrying 60L of water.
5 TABLE OF CONTE NTS page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 LIST OF FIGURES ................................ ................................ ................................ .......... 8 LIST OF ABBREVIATIONS ................................ ................................ ............................. 9 ABSTRACT ................................ ................................ ................................ ................... 10 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .... 12 1.1 Motivation ................................ ................................ ................................ ......... 12 1.2 Magnetic Ion Exchange ................................ ................................ .................... 12 1.3 Anion Exchange Resins ................................ ................................ .................... 13 1.4 Activated Carbon ................................ ................................ .............................. 13 1.5 Material Limitations ................................ ................................ ........................... 14 1.6 Critical Knowledge Needed ................................ ................................ ............... 15 1.7 Goals and Objectives ................................ ................................ ........................ 15 2 MATERIALS AND ME THODS ................................ ................................ ................ 18 2.1 Test Waters ................................ ................................ ................................ ...... 18 2.2 Anion Exchange Resins ................................ ................................ .................... 18 2.3 Act ivated Carbons ................................ ................................ ............................. 19 2.4 Kinetic Jar Tests ................................ ................................ ............................... 19 2.5 Equilibrium Jar Tests ................................ ................................ ........................ 20 2.6 Countercurrent Modeling ................................ ................................ .................. 21 2.7 Two stage Countercurrent Jar Tests ................................ ................................ 23 2.8 Analytical Methods ................................ ................................ ............................ 24 3 RESULTS AND DISCUSSION ................................ ................................ ............... 30 3.1 DOC Removal By Anion Exchange Resins ................................ ....................... 30 3.2 DOC Remov al By Activated Carbons ................................ ............................... 32 3.3 Modeling Two Stage Countercurrent Adsorption Process ................................ 34 3.4 Bench Scale Two Stage Countercurrent Process ................................ ............ 36 4 CONCLUSION ................................ ................................ ................................ ........ 46 APPENDIX: TWO STAGE COUNTERCURRENT MODELING SCENARIOS .............. 48 LIST OF REFERENCES ................................ ................................ ............................... 58
6 BIOGRAPHICAL SKETCH ................................ ................................ ............................ 62
7 LIST OF TABLES Table page 2 1 Collection date, UV 254 and SUVA for SJR water ................................ ................ 26 2 2 Anion exchange resins used and their properties ................................ ............... 27 2 3 Carbons u sed and their properties ................................ ................................ ..... 28 2 4 Two stage countercurrent method ................................ ................................ ...... 29 3 1 Adsorbents, isotherm parameters (K F and n), adsorbent do se to get 99% DOC removal of the adsorbable fraction of the total amount of DOC for single stage and countercurrent two stage reactor ................................ ............. 39 A 1 Modeling Freundlich constants ................................ ................................ ........... 49
8 LIST OF FIGURES Figure page 1 1 Schematic of two stage countercurrent reactor. ................................ ................. 17 3 1 Kinetic jar tests with AERs using water from SJR showing UVA 254 (C/C 0 ) as function of time and mixing speed. ................................ ................................ ..... 40 3 2 Kinetic jar tests with AERs using water from SJR showing DOC (C/C 0 ) at 30 min and different mixing speeds. ................................ ................................ ........ 41 3 3 Kinetic jar tests with GACs and PAC using water from SJR showing UVA 254 (C/C 0 ) as function of time and mixing speed. ................................ ...................... 42 3 4 Kinetic jar tests with GACs and PAC using water from SJR showing DOC (C/C 0 ) at final time (30 min) and different mixing speeds. ................................ ... 43 3 5 Equilibrium isotherms (q e vs. C e ). ................................ ................................ ....... 44 3 6 Counter current jar test showing absolute DOC for untreated (raw) water, 1st stage, and 2nd stage water ................................ ................................ ................ 45 A 1 Modeling for F400 with SJR water including non adsorbable fraction ................ 51 A 2 Modeling for F400 with SJR wat er excluding non adsorbable fraction ............... 52 A 3 Modeling for PFA444 with SJR water including non adsorbable fraction ........... 52 A 4 Modeling for PFA444 with SJR water excluding non adsorbable fraction .......... 53 A 5 Modeling for MIEX with SJR water including non adsorbable fraction ................ 53 A 6 Modeling for MIEX with SJR water excluding non adsorbable fraction ............... 54 A 7 Modeling for F400 with VA water including non adsorbable fraction .................. 54 A 8 Modeling for F400 with VA water excluding non adsorbable fraction ................. 55 A 9 Modeling for PFA444 with VA water including non adsorbable fraction ............. 55 A 10 Modeling for PFA444 with VA water excluding non adsorbable fraction ............ 56 A 11 Modeling for MIEX with VA water including non adsorbable fraction .................. 56 A 12 Mod eling for MIEX with VA water excluding non adsorbable fraction ................. 57
9 LIST OF ABBREVIATIONS AER Anion exchange resin Cl Chloride CMFR Completely mixed flow reactor DI Deionized DOC Dissolved organic carbon GAC Granular activated carbon MIEX Magnetic Ion Exchange ML Million liters NOM Natural org anic matter PAC Powdered activated carbon SJR St. Johns River SUVA Specific ultraviolet a b sorbance TOC Total organic carbon UVA 254 Ultraviolet a b sorbance and 254 nm VA Virginia
10 Abstract of Thesis Presented to the Graduate School of the University o f Florida in Partial Fulfillment of the Requirements for the Degree of Master of Engineering EVALUATION OF ANION EXCHANGE AND ADSORPT ION FOR NATURAL ORGA NIC MATTER (NOM) PRETREA TMENT FROM TWO SURFA CE WATERS USING A TW O STAGE COUNTERCURRENT REACTOR By Katherine Graf August 2013 Chair: Treavor H. Boyer Major: Environmental Engineering Sciences The goal of th is research was to investigate a two stage countercurrent sorption reactor for removal of dissolved organic carbon ( DOC ) with a variety of materials: magnetic ion exchange ( MIEX ) resin non magnetic anion exchange resins ( AERs ) granular activated carbon ( GAC ) and powdered activated carbon ( PAC ) Preliminary one stage reactor tests used natural surface water from the St. Johns River (SJR ) in Florida, with raw water DOC of ~17 mg / L. Preliminary experiments tested all materials at four different mixing speed and five different contact times. During the preliminary jar tests MIEX resin, non magnetic AERs, GAC, and PAC showed 54%, 20 30%, 5 1 0%, and 20% DOC removal at 200 rpm and 30 min contact time respectively. T he kinetics in the AERs and activate d carbons were slower than MIEX resin even though the AERs and carbons had higher capacity than MIEX resin A two stage countercurrent process wa s employed to load the DOC onto the resin and carbon by extending the solids contact time and making use of the concentration gradient between solution and solid phase material The two stage countercurrent experiments used MIEX, one non magnetic AER (PFA4 44), and one GAC (F400) with the SJR water and an additional
11 reservoir source from Virginia (VA), which had an average DOC of 3 mg /L. Isotherms and modeling w ere done to determine the doses necessary for 99% removal of the adsorbable fraction of DOC The a verage 2 nd stage percent removal of a d sorbable DOC removal with SJR water and VA water for F400, PFA444, and MIEX were 109 % and 84 % 90 % and 88 % and 85 % and 94 % respectively. These results show that the modeling was relatively effective in predicting the doses and that the two stage countercurrent process was able to remove more DOC than the single stage process
12 CHAPTER 1 INTRODUCTION 1.1 Motivation Natural organic matter (NOM) is a water constituent that is important for both drinking water treatment p rocess performance and finished water quality. NOM can cause chemical demands to increase, contribute to membrane fouling, and form disinfection by products ( Edzwald and Tobiason, 2011 ) As world populations increase utilities must increasingly rely on sou rces that are of a lower quality and have high NOM concentrations (Wang et al., 2010) This increases the need for enhance d NOM removal technologies, such as anion exchange and activated carbon treatment. Activated carbon adsorption (Jancan gelo et al., 199 5; Speth, 2001) and anion exchange (Boening et al, 1980) are two of the recommended technologies for removal of N OM from water 1.2 Magnetic Ion Exchange Several older studies have highlighted the potential of anion exchange resins (AERs) to remove NOM fro m drinking water sources (Anderson and Maier, 1979; Kunin and Suffet, 1980) and found that they out performed activated carbon (Boening et al., 1980). Traditionally, AERs have be en used in a fixed bed reactor, which requires water with a low turbidity to pr event excessive head loss due to clogging. This constrains the AER technology to be located later in the process train. Many recent studies have used AERs in a slurry reactor type, such as the magnetic ion exchange (MIEX) process, and has proven to be a pr omising technology for NOM removal from drinking water sources (Apell and Boyer, 2010; Bolto et al., 2002; Boyer and Singer 2008; Boyer et al. 2008 ). MIEX resin is a macroporous, polyacrylic, strong base AER. The resin is suspended in
13 a completely mixed fl ow reactor (CMFR) where the majority of resin stays in the reactor and a fraction of the resin goes to a regeneration side process. MIEX pre treatment studies have shown results for substantial removal of dissolved organic carbon ( DOC ) which can decrease subsequent chemical requirements (i.e. coagulant and chlori n e) and reduc e disinfection by product formation (Boyer and Singer, 2006; Singer et al., 2007). 1.3 Anion Exchange Resins By applying the MIEX process to non magnetic AERs it will allow them to be used near the beginning of the process train, prior to coagulation. In literature, only a few commercial AERs, other than MIEX, have been investigated for this type of reactor for NOM removal (Humbert et al., 2005; Tan et al., 2005 Cornelissen et al., 20 08). However, Bolto et al. (2002), investigated 20 different AERs, comparing their performance of NOM isolate removal by using the surrogate parameters: total organic carbon (TOC) and ultraviolet a b sorbance at 254 nm (UVA 254 ). Here they found that AERs of open structure and high water content were the best resin type for very efficient removal of any charged aquatic NOM, whether hydrophobic or hydrophilic. Cornelissen and colleagues (2008) had similar conclusions finding that removal of humic and fulvic sub stance s increased with an increase in water content of the investigated AER and decreased with increasing resin size. Thus, it is conceivable that non magnetic AERs could be used in a completely mixed, continuous flow process to remove NOM at the head of a water treatment plant 1.4 Activated Carbon The move for activated carbon from post treatment to pretreatment has only been studied for powdered activated carbons (PACs) (Uyak et al, 2007; Campos et al.,
14 2000). During a survey of 95 conventional treatmen t plants PAC wa s added to the following points of treatment: a continuous stirred tank reactor preceding rapid mix (7%), pre sedimentation (16%), rapid mix (49%), flocculation (10%), sedimentation (7%), and filter influent (10%) (Graham et al., 1997). Howe ver, PAC addition is usually added to target taste and odor compounds rather than NOM. Apart from trace contaminant removal, the need for enhance d NOM removal can be a driver for the installation of granular activated carbon (GAC) absorbers. GAC is typical ly used in a filter bed, which allows for an extended contact time 1.5 Material Limitations MIEX resin has been found to be cost prohibitive in some cases due to the resin loss experienced during pilot testing or by some full scale utilities. Brown and C ornwell (2011) reported a range from < 1 L of resin loss per million liters (ML) of water treated up to 11 L /M L. Activated carbon especially as a pretreatment step, is not widely u sed in practice for N OM control due to low capacity a nd slow adsorption kin etics of N OM by commercially available activated carbons. High operating costs if high PAC doses are required for long periods of time, the inability to regenerate, the low NOM removal, the increased difficulty of residuals management, and the difficulty o f completely removing the PAC particles from the water are several disadvantages of PAC according to Sontheimer (1976). However, GAC can be captured and regenerated. Studies have shown successful NOM removal via GAC absorbers in the back half of the proce ss train (Sontheimer et al., 1988; Kilduff et al., 1996). This however, does no t help reduce the chemical requirements (i.e. coagulant and chlorine ). Some of the commercially available AERs and GACs may need more consideration because they possess a highe r capacity than MIEX resin and may not experience the fragmenting that causes the MIEX resin
15 loss. Many of the non magnetic AERs also have a larger particle size that can reduce resin loss. However, with a higher density and particle size the AERs and GACs may need a differen t reactor, such as a two stage countercurrent reactor shown in Fig 1 1 which is expected to maximize the solids residence time and use concentration gradients to load the DOC more effectively on the sorbent material 1.6 Critical Knowl edge Needed A study comparing MIEX, non magnetic AERs, and activated carbons (GAC and PAC) performance of DOC removal in untreated surface waters is needed to bridge the gap between MIEX CMFR, AER CMFR and fixed bed, PAC CMFR, and GAC fixed bed studies. MI EX treatability of untreated surface waters has been studied ( Bolto et al., 2002; Boyer and Singer 2008; Boyer et al. 2008 ). AER use for untreated surface waters has been studied (Bolto et al., 2002; Humbert et al., 2005; Tan et al., 2005 Cornelissen et a l., 2008 ). PAC performance for DOC removal has also been studied (Uyak et al, 2007; Campos et al., 2000 ). Studies using GAC have focus ed only on GAC adsorbers (Velten, 2011; Lee et al., 1981; Karanfil et al., 1996; Kilduff et al., 1996; Summers and Roberts 1988) and not on a CMFR reactor type. Comparing MIEX, non magnetic AERs, and activated carbons in the CMFR reactor type will help give new insights on performance comparison 1.7 Goals a nd Objectives The goal of this work is to investigate the two stage countercurrent sorption reactor, shown in Fig 1 1, for DOC removal using MIEX resin non magnetic AERs, and activated carbons The specific objectives of this work are: (i) evaluate AER properties and test conditions ; (ii) evaluate activated carbon proper tie s and test conditions ; (iii) model DOC removal for a two stage countercurrent sorption reactor based on
16 equilibrium isotherms; and (iv) test the two stage countercurrent sorption reactor at the bench scale
17 Figure 1 1 Schemat ic of tw o stage countercurrent reactor
18 CHAPTER 2 MATERIALS AND METHODS 2.1 Test Waters One of the source waters used was from the St. Johns River (SJR) in Florida, more specifically the sample location was in Astor, FL. This water was used in all studies. More information regarding this sample location can be found in Walker and Boyer ( 2011 ) Samples were collected on the dates shown in Table 2 1. Samples were taken from either the east or west side of the river, from a dock 4 m from the river bank, using plastic 20 L Nalgene containers. Samples were delivered to the Department of Environmental Engineering Sciences, University of Florida within 3 h of collection and stored at 12C. The second water that was studied during th e isotherm, modeling and two stage countercurrent bench scale experiments was from a surface reservoir source located in Virginia, denoted as VA water. One 100 L sample was collected from a raw water tap at the treatment plant that uses this source prior t o any chemical addition. Samples were kept in five different Nalgene containers and delivered, over three days, to the Department of Environmental Engineering Sciences, University of Florida. All raw water samples were stored in a walk in refrigerator at 1 2C After experiments were conducted the tested samples were stored in the laboratory refrigerator which is maintained at 9.6 C 2.2 Anion Exchange Resins All of the AER s used in this study are listed in Table 2 2 along with their capacity, matrix, parti cle size and functional group. All of the data listed in Table 2 2 was provided by the manufacturer s and was not calculated or measured. All resins is that
19 were designated by the manufacturer for organic matter removal with chloride (Cl ) as the presatura nt ion. Anion exchange resin s were measured as the volume of wet settled resin in a graduated cylinder. All of the virgin AERs were regenerated before their initial use. All AERs were regenerated in a solution that contained 10 times more Cl than theoreti cally available on the highest capacity resin ( i.e., Marathon 11), consistant with previous work of Apell and Boyer (2010). All resins were regenerated with the same concentration ( 0.75 g NaCl/ m L resin/L water ). The virgin resin was mixed in the NaCl soluti on for 30 min at 200 rpm and then r insed in deionized (DI) water for 10 min at 200 rpm using a Phipps and Bird PB 700 jar tester 2.3 Activated Carbons All of the activated carbons used during this study are listed in Table 2 3 along with their type and ra w material. All of the data listed in Table 2 3 was provided by the manufacture r unless noted otherwise with superscripts Activated carbons were measured as a dry weight on a Mettler AE 160 analytical balance. Prior to use, DI water was added to the prev iously weighed carbon just to the point of complete wetness and was allowed to sit for 10 min. Then the carbon was added to 1 L volume of the sample water and the jar test began 2.4 Kinetic Jar Tests The kinetic jar test procedure for AERs and activated carbons w as as follows: mix at 50, 100, 150 and 200 rpm for 30 min with a Phipps and Bird PB 700 jar tester and allowed to settle for 5 min. Samples were collected at 5, 10, 15, and 20 min (no settling) and 30 min (after settling). Samples at 5, 10, 15 and 20 min were removed directly from the jar using a syringe fitted with a PVDF 0.45 m filter (Millex HV, Millipore) a nd analyzed for UV A 254 only. The final sample (after 30 min) was analyzed
20 for DOC and UVA 254 All resin doses were tested in triplicate and a control was done for each experiment. The control sample was untreated water mixed for 30 min followed by 5 min of no mixing before samples were withdrawn. All experiments were conducted with water that was at room temperature ; the temperature of the la b was approx. 24 C. All tests were conducted in a 1500 mL beaker with 1L of water. Results for UVA 254 and DOC are shown as the mean of triplicate samples with error bars showing one standard deviation 2.5 Equilibrium Jar Tests All equilibrium jar tests w ere mixed at 200 rpm for 2 h with 5 min of settling. A 50 mL sample was collected from each jar using a syringe filter as discussed in the previous section at the end of the settling time. The materials used during these experiments were PFA444, MIEX, an d F4 00. The doses used for the equilibrium jar tests for the SJR water were as follows: PFA444 doses were 1, 2, 4, 8, and 16 mL/L; MIEX doses were 0.6, 1, 2, 4, and 8 mL/L; F400 doses were 0.5, 2.5, 5, 10, 20 g/L. The doses used for the equilibrium jar tes ts for the VA water were as follows: PFA444 doses were 0.6, 1 2, 4, and 8 mL/L; MIEX doses were 0.6, 1, 2, 4, and 8 mL/L; F400 doses were 0.5, 2.5, 5, 10, 20 g/L. All doses were tested in triplicate and a control was done for each experiment. The control was untreated water mixed at 200 rpm for 30 min followed by 5 min of no mixing before samples were extracted. All tests were conducted in a 1500 mL beaker with 1L of water. All experiments were conducted with water that was at room temperature ; the tempera ture of the lab was 24 C. All samples were analyzed for UV A 254 and DOC.
21 2.6 Countercurrent Modeling The modeling approach was used to find the dose required for 99% DOC removal of the adsorbable fraction using a two stage countercurrent reactor. To do thi s the equilibrium data are necessary. A modified Freundlich equation was used to describe the equilibrium data following Treybal ( 1980 ): (2 1) where q e (mg DOC/g GAC or resin) and C e (mg DOC/L water) are equilibrium solid phase and solution concentrations, respectively, and K F and n are Freundlich constants. It is important to note that the Freundlich model in Eq uation 2 1 is de fined differently than the more common form Eq uation 2 2 : ( 2 2) which is defined in Weber and DiGiano ( 1996). This form in used to draw conclusions F and n cons tants from this equation. In Equation 2 3 C 0 is the raw water DOC concentration (mg/L) and D (g/L for carbon and L/L for resin) is the dose used for that isotherm point. ( 2 3 ) For the AERs density was found by measuring 3 mL of resin in a graduated cylinder, then the resin was place d in a desiccator for 48 h to dry. The resin was weighed to give the density. Th e density was used to convert q e from mg DOC/ L resin to mg DOC/g resin. To find the dose for the two stage countercurrent jar tests the non adsorbable fraction of DOC was subtracted from the total DOC to make a new isotherm. The DOC concentration that was not removed by the highest dose in the isotherm was
22 approximately equal to that of the second highest dose and therefore, was divided by the initial (raw water) DOC to give the non adsorbable fraction. With the data from the equilibrium jar tests, the Freundlich isotherm constants K F and n were found. The log of the C e values, the DOC concentration of the water after treatment by each dose, w as plotted on the y axis and the log of the q e Equation 2 3 w as plotted on the x axis of the graph. From the graph a line was fit to the form y = ax + b format. Where K F was equal to 10 b and n was equal to a. Using Treybal ( 1980 ) the following equation Equation 2 4 was us ed and solved with Microsoft Excel Solver (Excel 2010) to find the concentration after stage 1 to reach 99% removal at the end of stage 2 (2 4 ) where C 1 is the DOC concentration leaving stage 1, C 2 is the DOC concentration leaving stage 2, and all concentrations refer to the removable fraction of DOC. C 0 is known and C 2 is found using Eq uation 2 5 because of the criteria of 99% removal (2 5 ) With C 1 calculated from Equation 2 4 the necessary dose for the system can be found usi ng the following equation, Equation 2 5 : (2 6 ) where D 2 is the dose for the two stage countercurrent jar test. To compare the dose of the two stage countercurrent system to the regular single stage jar test that achieves the same removal the following equation was used:
23 (2 7 ) where D 1 is the dose for the single stage jar test. Eq uation 2 7 eliminates the C 1 value and goes to C 2 because there is only one stage and no intermediate stage. Screenshots of excel spreadsheets and isotherms for each modeling scenario are shown in the Appendix A The K F and n valu es used for the model, found using Eq uation 2 1, where then converted to represent the K F and n values that are in Equation 2 2. To do this Eq uation 2 1 was algebraically manipulated to have the left hand side equal q e as Eq uation 2 2 has, this results in the following, Eq uation 2 8 : (2 8) Therefore, we must take the n that resulted using Eq uation 2 1 and take the inverse, to get wh at is represented in Eq uation 2 2. Also, the K F from the Eq uation 2 1 model must be raised to the 1/n and then the inverse must be taken to give what Eq uation 2 2 K F represents. 2.7 Two stage Countercurrent Jar Tests For these experiments only the material s for which isotherms were developed were used. The two stage c ountercurrent jar tests were done in 6 steps, or 6 jar tests in series. All steps were mixed at 200 rpm for 30 min and given 5 min to set tle (no mixing) using a Phipps and Bird PB 700 jar teste r. All tests were conducted in a 1500 mL beaker with 1L of water. The 6 steps are listed in Table 2 4 and are briefly described as follows:
24 Step 1 has fresh, unused material (GAC or AER), mixed with raw, untreated water to produce once used material that is discarded and 1 st stage treated water. In Step 2 fresh unused material (GAC or AER) is mixed with the 1 st stage treated water from the previous step to produce once used material and 2 nd stage treated water. Step 3 has th e once used material from the previous step being mixed with raw water to produce twice used material that is discarded and 1 st stage treated water. Step 4 has the same description as Step 2, Step 5 as Step 3, and Step 6 as Step 2. This type of jar test was designed to mimic a set up similar to that shown in Figure 1 1 I n Table 2 4 the twice used material (GAC or AER) is disc arded but in Figure 1 1 the twice used material goes to regeneration which is discussed in more detail in section 3.4. 2.8 Analytical Methods DOC was measured u sing a Shimadzu TOC V CPH total organic carbon analyzer equipped an ASI V autosampler. The standard solution for DOC was prepared from potassium hydrogen phthalate. All DOC samples were measured in duplicate with average values reported. The relative differ ence, the difference between the actual v alue and results divided by the actual value and multiplied by 100 for DOC calibration check standards was < 6% for the entire duration of the project using the 5 mg/L DOC
25 standard. UV absorbance was measured at a 254 nm wavelength on a Hitachi U 2900 spectrophotometer using a 1 cm quartz c uvette
26 Table 2 1 Collection date, UV 254 and SUVA for SJR water Collection Date Average DOC (mg C/L) Average UV 254 (1/ c m) SUVA (L/mg*m) Type of Jar T est Mixing, rpm Material Dose 5/14/2012 13.1 0.471 3.6 Preliminary 50, 100, and 150 a, b 0.5 g/L 200 a 0.5 g/L 5/18/2012 11.1 0.389 3.5 Preliminary 50 and 100 c, d, e, f, g, h,i 2 mL/L 150 c, d, e, h 2 mL/L 6/5/2012 7.4 0.268 3.6 Preliminary 50 and 100 k, j 0.5 g/L 150 f, g, i 2 mL/L 200 c, d, e, f, g, h, i 2 mL/L a 0.5 and 5 g/L b 5 g/L 7/15/2012 22.5 0.725 3.2 Preliminary 50 and 100 j, k 0.5 g/L 200 j, k 0.5 and 5 g/L Isotherm 200 b 0.5,2.5, 5, 10, 20 g /L c 1, 2, 4, 8, 16 mL/L 8/10/2012 20.6 0.643 3.1 Counter current 200 b 6 g/L c 8 mL/L i 2 mL/L 11/15/2012 27.5 1.200 4.4 Isotherm 200 i 0.6, 1, 2, 4, 8 mL/L a=HD3000, b=F400, c=PFA444, d=A850, e=Marathon11, f=Tan1, g=Tanex, h=A50 0P, i=MIEX, j=Aquacarb, k=PAC500
27 Table 2 2 Anion exchange resins used and their properties Resin Type Manufacturer Capacity (eq/L) Particle Size (mm) Functional Group Matrix Water Content (%) MIEX Orica Watercare ~0.5 0.2 Quat ernary Ammonium Acrylic, Macroporous -DOWEX MARATHON 11 DOW 1.3 0.55 Quaternary Ammonium Styrene, Gel 48 58 DOWEX TAN 1 DOW 0.7 0.81 Quaternary Ammonium Styrene, Macroporous 70 82 Purofine PFA444 Purolite 1.1 0.57 Quaternary Ammonium Styrene, Gel 50 6 0 Purolite A500P Purolite 0.8 0.75 Quaternary Ammonium Styrene, Macroporous 63 70 Tanex Purolite 0.75 Quaternary Ammonium Styrene and Acrylic, Macroporous and Gel 68 75 Purolite A850 Purolite 1.25 0.75 Quaternary Ammonium Acrylic, Gel 57 62
28 Table 2 3 Carbons used and their properties Carbon Name Manufacturer Carbon Type Raw Material SA BET (m 2 /g) V micro (cm 2 /g) V meso+macro (cm 2 /g) Hydrodarco 3000 (HD3000) Norit GAC lignite coal 676 a 0.265 a 0.445 a Filtrasorb 400 (F400) C algon Carbon GAC bituminous coal 1035 b 0.404 b 0.149 b Aquacarb CX Siemens GAC coconut shell ---PAC500 Siemens PAC Coconut/ Coal ---a Cheng, W., Dastgheib, S.A., Karanfil, T., 2005. Adsorption of dissolved natural organic matter by modified ac tivated carbons. Water Research, 39, 2281 2290. b Dastgheib, S.A., Karafil, T., Cheng, W., 2004. Tailoring activat e d ca rbons for enhanced removal of na tural organic matter from natural waters. Carbon, 42, 547 557.
29 Table 2 4 Tw o stage countercurrent method Step Start of experiment Experiment Yield Material Stage + Water Stage Material Stage + Water Stage (Sample Type) 1 Fresh (Virgin with pre regeneration) + Raw Once used (discarded) + Once Treated (1 st Stage) 2 Fresh + 1 st Stage Once used + 2 nd Stage 3 Once used + Raw Twice used (discarded) + 1 st Stage 4 Fresh + 1 st Stage Once used + 2 nd Stage 5 Once used + Raw Twice used (discarded) + 1 st Stage 6 Fresh + 1 st Stage Once used + 2 nd Stage
30 CHAPTER 3 RESULTS AND DISCUSSION 3 .1 DOC Removal b y Anion Exchange Resins Results for kinetic jar tests using anion exchange resins are shown in Fig. 3 1 and 3 2 All resins during these experiments were tested at a 2 mL/L dose. The 2 mL/L resin dose is equivalent to appro ximately 500 bed volumes and is therefo re a reasonable dose for a full scale process. Normalized values of UV A 254 for different mixing speeds as a function of time are shown in Fig. 3 1 All resins, except for MIEX and A850, performed similarly at all mixi ng speeds. For MIEX and A850, removal of UVA 254 at difference mixing speed was 200 rpm ~ 150 rpm > 100 rpm > 50 rpm. In Ding et al. (2012a) the optimum bromide removal with MIEX was 100 rpm because at that speed the resin dose used was equally distributed throughout the sample volume. However, there was no additional removal any speed higher than 150 rpm with MIEX for phosphate and 2,4 dischlorphenoxyacetic acid removal because the increased mixing intensity caused the boundary layer thickness around the re sin particles to decrease and the turbulence to increase ensuring an intimate contact between phases (Ding et al., 2012b; Ding et al., 2012c). Visual observation during these experiments showed that for some of the resins, due to larger particle size and density, the resins were not evenly distributed until 200 rpm. It should be noted that the rpm in these studies are not equal mixing as the rpm in the Ding studies. The rpm in the Ding studies would represent a higher velocity gradient than the equilivalen t rpm in these tests. This is because the paddle diameter (equal to this study) to jar diameter (1L beaker in Ding study, 1.5L beaker in this study) ratio is higher and the volume of water treated (500 mL in Ding and 1 L in is study) lower in the Ding stud ies compared to this study, which according to
31 Cornwell and Bishop (1983) would result in a higher velocity gradient The results show that for some of the denser, larger resins faster mixing speed did not prove to be an important factor ( Fig 3 1 ) which suggests equal distribution did not appear to be a requirement. However, since doses may increase or change throughout the study, all subsequent experiments, isotherms, and two stage countercurrent jar tests were conducted at 200 rpm. The percent UVA 254 r emoval for the 200 rpm mixing speed at 30 min performance among all AERs was: MIEX (69%) > PFA444 (31%) Tan1 (29%) Marathon11 (28%) A850 (27%) Tanex (26%) > A500P (11%). Normalized DOC concentrations as a function of mixing speed for the final tim e, 30 min, is shown in Fig. 3 2 for the AERs The average initial DOC from the controls for these experiments was 11 mg /L wi th a standard deviation of 2 mg /L. Mixing speed had less of an effect on the DOC removal of the AERs, a reason for this is the incre ased variability in the DOC measurements compared to the UVA 254 measurements, causing that measurement to be more sensitive to mixing speed. The order of DOC removal at 200 rpm performance was: MIEX (45%) > Tan1 (25%) PFA444 (25%) A850 (23%) Marathon11 (22%) Tanex (21%) > A500P (8%). Due to storage capacity three different sampling trips where made to conduct the experiments shown in Fig 3 1 and 3 2 ; this aspect can add some variation between data points, informa tion concerning sample date and experiment can be found in Table 2 1. All of the resins presented in Fig 3 1 and 3 2 are strong base AERs, meaning they contain quaternary ammonium groups, and are T ype I, trimethyl am ine These resins remove more NOM compar ed to weak base resins (Bolto et al., 2002) and Type I
32 strong base generally exhibit more selectivity for NOM removal then Type II, dimethylethanol am ine As shown in Table 2 1, resins used in this research were either macroporous or gel type. Resins with a macrop orous structure generally remove more NOM than resins with a gel structure according to Bolto et al. (2002). This is because organic anions, humic acids, can diffuse easier within a macroporous structure. However, Tan et al. (2005) have contrasting findings with gel structures removing more NOM than macroporous resins. This is explained by higher swelling capacity of the gel resins in water. Following from the order of UVA 254 and DOC removal and resin properties, there is no association between gel or macroporous structure, water content or styrene or acrylic material For all of the resins the specific ultraviolet a b sorbance ( SUVA ) decreased from the raw water sample (3.6L/mg m) to the 200 rpm mixed sample after 30 min of mixing. MIEX experienced the largest decrease in SUVA (2.1 L/mg*m) then PFA444 (3.3 Tan1 (3.4 L/mg*m) > A500P (3.5 L/mg*m). This means that all of the AERs preferentially remove aromatic UV absorbing carbon and the MIEX has an affinity greater than the other AER S for aromatic carbon. Humbert and colleagues (2005) have reported that Resins with a styrene structure display a greater affinity for aromatic components than resin s based on an acrylic structure. However, with this SUVA data MIEX has the greatest affinit y and its structure is acrylic. 3 .2 DOC Removal b y Activated Carbons To properly compare GAC and AER performance as a pretreatment for NOM the kinetic jar tests must be the same length of time and therefore at a much shorter time
33 than is typically used whe n investigating GAC performance. Also, the end goal is to use the carbons that are in the preliminary jar tests, as explained in section 2.4, in the two stage countercurrent jar tests, as explained in section 2.7. The results for activated carbon kinet ic j ar tests are shown in Fig. 3 3 and 3 4 I n Fig. 3 3 the normalized UVA 254 concentration for various mixing speeds (50, 100, 150, 200 rpm) for a 0.5 g/L dose and 200 rpm for a 5 g/L dose as a function of time for all carbons listed in Table 2 3. The doses, 0.5 g/L and 5.0 g/L, are much greater than what is typically used in practice but was necessary for this preliminary treatment to compare the performance between the carbons and with the AERs. For the 0.5 g/L dose the UVA 254 removal for the 200 rpm mixing speed at 30 min was PAC 500 (15%) > F400 (11%) > HD3000 (9%) > Aquacarb (7%). UV A 254 r emoval did not increase with time for the GACs at the 0.5 g/L dose this could be because there was n o t an adequate amount of activated carbon added and therefore signifi cant removal did not occur The varying trend between the 50 rpm and 100 rpm versus the 150 rpm and 200 rpm mixing speeds in Fig. 3 3c. and 3 3 b. can be explained by use of water from different sampling dates shown in Table 2 1. The PAC was also more resp onsive than the GACs to increased mixing speed at the 0.5 g/L dose. The 5 g/L all carbons experienced an increase in removal with time. The trend of removal for this dose at 200 rpm was PAC500 (78%) > HD3000 (57%) > F400 (52%) > Aquacarb (49%). Normalize d DOC concentrations for all carbons as a function of mixing speed is shown in Fig. 3 4 The first four sections are at a dose of 0.5 g/L (50, 100, 150, 200 rpm) and the last is for a dose of 5 g/L at 200 rpm. For the 200 rpm mixing speed for the 0.5 g/L t he DOC removal performance was PAC500 (16%) > HD3000 (9%)
34 Aquacarb (9%) > F400 (7%) and for the 5 g/L dose was PAC500 (78%) > HD3000 (57%) > F400 (52%) > Aquacarb (49%). The DOC and UV A 254 results show HD3000 and F400 giving similar removal, even though HD300 has a meso and macropore volume three times that of F400. Previous research shows NOM adsorption primarily takes place in mesopores (2 50 nm width) and large micropores (1 2 nm width) (Lee et al., 1981; Summers and Roberts, 1988; Newcombe et al., 1997; Pelekani and Snoeyink, 1999; Cheng et al., 2005). Velt en and colleagues (2011) found that to achieve high NOM removal efficiency with GAC adsorption, GAC s with a high surface are and large volume of pores with widths of 1 50 nm should be selected. For F400 and HD3000 SUVA decreased from the raw water sample ( average from different sampling dates of 3.7 L/mg*m) to the 200 rpm mixed sample after 30 min of mixing. F400 experienced the largest decrease in SUVA (3.4 L/mg*m), and HD3000 did not experience much of a decrease (3.6 L/mg*m). The two coconut based carbon s experienced an increase in SUVA, Aquacarb with a greater increase (3.9 L/mg*m) followed by PAC500 (3.8 L/mg*m). 3 .3 Modeling Two Stage Countercurrent Adsorption Process The isotherms presented in this work (2 hours) are much shorter than typical isotherm s (1 to 2 weeks) (Dastgheib et al., 2004; Cheng et al., 2005; Smith, 1994). Since these isotherms are being used to model necessary doses for the two stage countercurrent set up, which is only 30 min contact times. Isotherm data and Freundlich modeling for SJR (top row) and VA (bottom row) wa ter are shown in Fig. 3 5 using F400 (a and d), PFA 444 (b and e), and MIEX (c and f). The Freundlich isotherm constants, K F and n for Fig. 3 5 using Eq uation 2 2 and the manipulation of the modeling KF and n values di scussing in section 2.6, can be found in Table 3 1 The
35 original K F and n values from Equation 2 1 can be found in the Appendix. For a given value of K F a lower n reflects a great er solute affinity; th e Freundlich isotherm is convex (favorable) for n < 1, linear for n = 1, and concave (unfavorable) for n > 1. For a given value of n, a higher K F dire ctly reflects a greater sorption capacity at a specific solution phase concentration, specific capacity ( Weber and DiGiano, 1996). The order of K F constants are MIEX > PFA444 > F400 for SJR and VA water This agrees with the modeled doses needed shown in Table 3 1 and the preliminary results shown in Figures 3 1 through 3 4. The order of n constants are F400 > MIEX > PFA444 for the SJR and VA waters. From previou s published literature it is apparent that not all of the NOM in natural water is removable by anion exchange resins (Bolto et al., 2004; Boyer et al., 2008; Fettig, 2005). All isotherms illustrate that the water possesses a non adsorbable fraction of NOM. The non adsorbable fraction for this work was defined by the highest dose used for the isotherm, which was when no more removal was achieved by increasing the dose. In Fig. 3 5 this would be the point with the lowest q e and C e where the vertical line int ersects the x axis indicates the non adsorbale fraction. This is what was subtracted from each point for the two stage countercurrent modeling. The non adsorbable fraction for the SJR and VA water F400, PFA444, and MIE X isotherms are found in Table 3 1 an d show values from 12% to 31 % non adsorbable. Previously reported ranges of non adsorbable fractions range from <10% to approximately 40% for different NOMS and AERs (Bolto et al., 2004). The non adsorbable fraction can vary because the raw water varied wi th different sampling dates and also because the materials have diff erent sorption properties. For e xample, a pproximately 75% of the
36 F400 surface area is located within the pores smaller than 1 nm in nominal diameter On the other hand, the average sizes o f NOM components have been reported to be between 0.5 and 5 nm (Reckhow et al., 1990; Karanfil et al., 1999). So, it is evident that some N OM will be excluded from adsorption The most important mechanism for NOM r emoval via AERs is the exchange of ions, t he exchange from NOM acids and chloride ions ( Boyer and Singer, 2008; Tan et al., 2005), rather than physical adsorption. However, for the carbon the adsorbent pore size distribution appears to be the principal factor controlling NOM uptake by GAC while el ectrostatic effects play a secondary role (Newcombe et al., 2002). The doses found using the isotherms, non absorbable fraction, and modeling for single stage and two stage cou ntercurrent are found in Table 3 1 3.4 Bench Scale Two Stage Countercurrent Pro cess The absolute DOC (mg/L) meaning that these values are not normalized by the initial concentration of the raw water, results for the two stage countercurrent jar tests with F400 (a and d), PFA444 (b and e), and MIEX (c and f) for the SJR (top row) and VA (bott om row) water are found in Fig. 3 6 The first bar represents the raw water. The second bar, 1 st stage treated water, in cycles 1, 2, and 3 represents the product of steps 1, 3, and 5, respectively, described in Table 2 4 The third bar, 2 nd stage treated water, represents steps 2, 4, and 6, respectively, described in Table 2 4. Raw water for SJR jar tests was collected in one trip for countercurrent jar tests but a different sampling trip from the isotherm water, as described in Table 2 1, and var ied from 23.6 to 17.9 mg/L (standard deviation of 2.8 m g/L) between raw water for Fig. 3 6 a, b, and c. The raw wa ter f r o m VA was collected in one trip, also the same trip as the isotherm water, and varied from 2.9 and 3.4 mg/L (standard deviation of 0.17 m g/L ) between raw water for
37 Fig. 3 6 d, e, and f. This variation could be from storing the water in different containers and not mixing the water within the container before measuring the volume needed for the experiment. The doses chosen for this experimen t were based on the m odeling and are found in Table 3 1 Fig. 3 6 shows consistent performance between cycles 1, 2, and 3. This means that the experiment was able to reach a steady state removal in stage 1 and 2. The target removal t hat was modeled for wa s 99% o f the adsorbable fraction. Fig. 3 6 shows the total DOC which includes the adsorbable and non adsorbable fractions The average 1 st stage and 2 nd stage percent of total DOC removal with SJR water for F400, PFA444, and MIEX were 58 % and 82 % 43 % and 68 % and 56 % and 74 % respectively. The average 1 st stage and 2 nd stage percent of total DOC removal with VA water for F400, PFA444, and MIEX were 42 % and 69 % 35 % and 59 % and 45 % and 65 % respectively. From the isotherms we know t he percent of DOC that i s non ad sorbable for each material and water. Subtracting the fraction of non adsorbable fraction from the treated and raw water results shows how close to the target of 99% removal was achieved. The average 1 st stage and 2 nd stage percent of adsorbable DO C only removal with SJR water for F400, PFA444, and MIEX were 82 % and 109 % 62 % and 90 % and 66 % and 85 % respectively. The over 100% removal suggests that part of the calculated non adsorbable fraction was removed. The average 1 st stage and 2 nd stage per cent of ad sorbable DOC only removal with VA water for F400, PFA444, and MIEX were 56 % and 84 % 61 % and 88 % and 69 % and 94 % respectively. These numbers show that the achieved adsorbable DOC removal at the 2 nd stage was close to
38 the 99% targe t of non adsor bable DOC removal. This shows that the isotherms and modeling were reasonable for this system. Using MIEX resin as an example, since the doses in the two stage countercurrent and kinetic study are equivalent for the SJR water scenario it is evident that t he two stage process was able to increase DOC removal and loading onto the resin. For the kinetic tests, which mimic a one stage system, 2 mL/L of MIEX with the SJR water and achieved ~45% DOC removal, shown in Fig. 3 2 In the two stage countercurrent sys tem 2 mL/L of MIEX with the SJR water achieved 82% removal after the 2 nd stage. There are, however, some practical implications that must be considered. In comparison to a single stage process the two stage counter current who have high capital cost becaus e of the increased infrastructure necessary due to the need for two tanks rather than one higher energy cost because of the system will require more mixing and pumping to move water and material, and lower chemical cost because it will allow the water to have a lower dose to achieve equivalent removal. Regeneration must also be considered. AERs have easy and proven on site regeneration; however, the waste brine residual must be managed. Typically GAC is regenerated off site; but, some on site thermal and e lectrochemical regeneration research (Narbaitz and McEwen, 2012) can make GAC a much more appealing material.
39 Table 3 1. Adsorbents isotherm parameters (K F and n ), adsorbent dose to get 99% DOC removal of the ad sorbable fraction of the total amount of DO C for single stage and countercurrent two stage reactor Adsorbent Water Source Freundlich isotherm Adsorbent dose to achieve 99% removal Dose used for countercurrent jar test Non abs % K F n single stage countercurrent two stage F400 SJR 26 1.68 0.67 34 5 6 g/L PFA444 SJR 23 1.79 0.49 39 8 8 mL/L MIEX SJR 12 9.32 0.58 11 2 2 mL/L F400 VA 17 1.64 0.54 12 2 3 g/L PFA444 VA 31 1.98 0.41 9 2 3 mL/L MIEX VA 29 5.64 0.41 3 1 1 mL/L
40 Figure 3 1 Kinetic jar tests with AERs using w ater from SJR showing UVA 254 (C/C 0 ) as fu nction of time and mixing speed. (a) MIEX, (b) PF444, (c) Tan1, (d) A850, (e) Marathon, (f) Tanex, and (g) A500P all at a dose of 2 mL/L. Data are the mean of triplicate samples; error bars show one standard deviati on (typically inside symbol).
41 Figure 3 2 Kinetic jar tests with AERs using water from SJR showing DOC (C/C 0 ) at 30 min and different mixing speeds. AERs are in the order (left to right) of MIEX (solid black), PFA444 (light downward diagonal), Tan1 (so lid white), A850 (light horizontal), Marathon11 (solid gray), Tanex (dot), A500P (wide upward diagonal).
42 Figure 3 3 Kinetic jar tests with GACs and PAC using water from SJR showing UVA 254 (C/C 0 ) as fu nction of time and mixing speed. (a) F400, (b) HD3000, (c) Aquacarb, and (d) PAC500. The first number in the key represents the rpm that the sample was stirred at and the number after the hyphen is the dose of carbon in g/L.
43 Figure 3 4 Kinetic jar tests with GACs and PAC using water from SJR showing DOC (C/C 0 ) at final time (30 mi n) and different mixing speeds. T he first set of rpm is for 0.5 g/L and the 200 5.0 is for 5.0 g/L of carbon. Carbons are in the order (left to right) of F400 (solid black), HD3000 (light downward diagonal), Aquacarb (solid white), PAC 500 (light horizontal).
44 Figure 3 5 Equilibrium isotherms (q e vs. C e ). (a) F400, (b) PFA444, and (c) MIEX for SJR (top row) and (d) F400, (e) PF444, and (f) MIEX for Virginia water (bottom row). The line is the Freund lich isotherm fitted to the actual data (red triangles). c
45 Figure 3 6 Counter current jar test showing absolute DOC for untreated (raw) water, 1st stage, and 2nd stage water (a) F400, (b) PFA444, and (c) MIEX for SJR (top row) and (d) F40 0, (e) PFA444, (f) MIEX for Virginia water (bottom row). The solid black bar, the light downward diagonal bar, and the solid white bar represent the raw (untreated water), 1st stage, and 2nd stage treated waters, respectively.
46 CHAPTER 4 CONCLUSION T he two stage countercurrent set up was able to load more DOC onto the resin and GAC than just one stage for the SJR water, since this was the only water used during the kinetic jar tests. Comparing the kinetic jar test loading for the final time, 30 min, a t 200 rpm to the loading for the 2 nd stage water in the two stage countercurrent experiments that were also mixed at 200 rpm for 30 min for the SJR, the two stage countercurrent set up loaded 2.2 mg DOC/g F400, 0.52 mg DOC/ mL PFA444, and 5.13 mg DOC/mL MI EX more than the kinetic, one stage, tests. All two stage countercurrent figures appear similar as far as relative DOC removal at each stage indicat ing that the two stage modeling did a reasonable job giving doses needed for the target removal. It also in dicated that the 2 h isotherm time was sufficient for the modeling purposes MIEX was able to achieve the same removal with 1 / 4 and 1 / 3 the amount of resin of the PFA444 for the SJR and VA waters, respectively. However, with 1 L of MIEX resin loss per 1 ML water treated (Brown and Cornwell, 2011) this fraction could change if PFA444 resin loss is experienced in pilot or full scale. Cost, regeneration, and resin loss potential need to be explored before declaring which material will be best for the two stag e counter current process. Resin and carbon unit cost and regeneration need to be compared to appropriately compare carbon dose with MIEX There was no clear trend between resin properties and performance. It is possible that the other resins will perform better in a column process and therefore, more work
47 must be done with these resins to explain why their high capacity does not get more removal than the lower capacity resins (i.e. MIEX).
48 A PPENDIX TWO STAGE COUNTERCURRENT MODELING SCENARIOS This part of the appendix shows screen shots of the spreadsheets for each modeling s cenario. The Figure A 1 will be the most detailed. When the cell is occupied by an equation that equation will be defined in Fig ure A 1 All subsequent figures will follow the same for mat as Fig ure A 1 The difference will be a different material and/or treatment water. The top table (A3:E8) represent isotherm data. Column A in this table represents the doses chosen for the isotherm and are represented as kg/L or L/L depending on if the material is GAC or resin, respectively. Information in row 3 in this table represents the raw, untreated water. Column B is the aqueous phase equilibrium concentration. From this concentration the solid phase equilibrium concentration is calculated and th e equation is found on Fig ure A 1 From columns B and C logarithmic values are taken to make up columns D and E, respectively. The logarithmic values are plotted in the graph, with log(q e ) making up the x axis and log(C e ) making up the y axis. A line is fi t to the data in the graph and the equation is displayed on the graph in the linear form shown (y = ax + b). The a and b values from this fitted line are used to find Freundlich constants, equations are displayed in Fig ure A 1 The C0 cell (B12) is equal t o the raw was concentration in cell B3. The C2 cell (B14), the concentration leaving stage 2, is calculated by multiplying the raw water concentration by 0.01. This is because we are looking to remove 99% of the DOC. Cells B16 and B17 represents the left h and side and right hand side of the equation shown in Fig ure A 1 Using solver cell B17, right hand side of the equation, is set as the objective function to equal a value of 99, which is what the left hand side equals since our target is 99% removal. The variable cell in solve is set to equal B13, the concentration of the water leaving stage 1.
49 Now that C1, cell B13, is found the GAC or resin dose for a two stage counter current or single stage set up can be found. The K F and n values that were used in th e modeling are shown in the screenshots and in Table A 1 Table A 1 Modeling Freundlich constants Adsorbent Water Source Modeling Freundlich K F n F400 SJR 0.46 1.50 PFA444 SJR 0.30 2.06 MIEX SJR 0.02 1.71 F400 VA 0.40 1.86 PFA444 VA 0.19 2.44 MI EX VA 0.01 2.45 Figure A 1 is showing the modeling for the F400 carbon with SJR that includes the non adsorbable fraction and that is why the doses that for calculated are so high. Figure A 2 shows the same isotherm information but subtracts the non adso rbable fraction from the C e (B3:B8) values. The non adsorbable fraction for the case of the F400 was found to be equal to the average of the last two points since removal was greater for the fourth point than the fifth. This is probably due to error associ ated with DOC measurements. Due to the averaging one of the C e values comes out to be negative so that value point was not plotted. Like Fig ure A 1 and A 2 Fig ure A 3 and A 4 go together in the same way, except with PFA444 resin and SJR water. Fig ure A 3 is the including and Fig ure A 4 is excluding the non adsorbable fraction. For this isotherm the non adsorbable equaled the C e in point 5, cell B8 in Figure A 3 Figure A 5 and A 6 shows MIEX with SJR water isotherm and modeling, including and excluding the non
50 adsorbable fraction. For this isotherm the non adsorbable equaled the C e in point 5, c ell B8 in Figure A 5 Figure A 7 and A 8 show F400 with VA water isotherm and modeling, including and excluding the non adsorbable fraction. The non adsorbable fract ion was found to be equal to the average of the last two points since removal was greater for the fourth point than the fifth, like the case for F400 in SJR water. Fig ure A 9 and A 10 shows PFA444 with VA water isotherm and modeling, including and excludin g the non adsorbable fraction. For this isotherm the non adsorbable equaled the C e in point 5, cell B8 in Fig ure 10 Figure A 11 and A 12 shows MIEX with VA water isotherm and modeling, including and excluding the non adsorbable fraction. For this isotherm the non adsorbable equaled the C e in point 5, cell B8 in Fig. A 12 However, points 3, 4, and 5 yeilded similar C e values which threw off the linear trend for the log plots. Therefore, points 4 and 5 were excluded to give a better fit.
51 Figure A 1 Mode ling for F400 with SJR water including non adsorbable fraction
52 Figure A 2 Modeling for F400 with SJR water excluding non adsorbable fraction Figure A 3 Modeling for PFA444 with SJR water including non adsorbable fraction
53 Figure A 4 Modeling for PFA444 with SJR water excluding non adsorbable fraction Figure A 5 Modeling for MIEX with SJR water including non adsorbable fraction
54 Figure A 6 Modeling for MIEX with SJR water excluding non adsorbable fraction Figure A 7 Modeling for F400 wi th VA water including non adsorbable fraction
55 Figure A 8 Modeling for F400 with VA water excluding non adsorbable fraction Figure A 9 Modeling for PFA444 with VA water including non adsorbable fraction
56 Figure A 10 Modeling for PFA444 with VA water excluding non adsorbable fraction Figure A 11 Modeling for MIEX with VA water including non adsorbable fraction
57 Figure A 12 Modeling for MIEX with VA water excluding non adsorbable fraction
58 LIST OF REFERENCES Anderson, C.T., Maier, W.J., 1979. Tr ace organics removal by anion exchange resins. Journal AWWA 71 (5), 278 283. Apell, J. N., and Boyer, T. H., 2010. Combined ion exchange treatment for removal of dissolved organic matter and hardness. Water Research 44(8), 2419 2430. Boening, P.H., Beckman n, D.D., Snoeyink, V.L., 1980. Activated carbon versus resin adsorption of humic substances. Journal AWWA 72 (1), 54 59. Bolto, B., Dixon, D., and Eldridge, R., 2004. Ion exchange for the removal of natural organic matter. Reactive & Functional Polymers 60 171 182. Bolto, B., Dixon, D., Eldridge, R., King, S., and Linge, K., 2002. Removal of natural organic matter by ion exchange. Water Research 36(20), 5057 5065. Boyer, T. H., and Singer, P. C., 2008. Stoichiometry of removal of natural organic matter by ion exchange. Environmental Science & Technology 42(2), 608 613. Boyer, T. H., Singer, P. C., and Aiken, G. R., 2008. Removal of dissolved organic matter by anion exchange: Effect of dissolved organic matter properties. Environmental Science & Technology 4 2(19), 7431 7437. Boyer, T.H., Singer, P.C., 2006. A pilot scale evaluation of magnetic ion exchange treatment for removal of natural organic material and inorganic anions. Water Research 40 (15), 2865 2876. Brown, R.A., Cornwell, D.A., 2011. Impact of An ion Exchange Pre Treatment on Downstream Processes. Water Research Foundation. Campos, C., Schimmoller, L., Marinas, B.J., Snoeyink, V.L., Baudin, I., Laine, J.M., 2000. Adding PAC to remova DOC. Journal AWWA 92(8), 69 83 Cheng, W., Dastgheib, S.A., Kara nfil, T., 2005. Adsorption of dissolved natural organic matter by modified activated carbons. Water Research 39, 2281 2290. Cornelissen, E. R., Moreau, N., Siegers, W.G., Abrhamse, A.J., Rietveld, L.C., Grefte, A., Dignum, M., Amy, G., Wessels, L.P., 2008. Selection of anionic exchange resins for removal of Natural Organic Matter (NOM) fractions. Water Research 42(1 2), 413 423. Cornwell, D.A., Bishop, M.M., 1983. Determining velocity gradients in laboratory and full scale systems. Journal AWWA 75(9), 470 4 75.
59 Dastgheib, S.A., Karafil, T., Cheng, W., 2004. Tailoring activatd carbons for enhanced removal of antural organic matter from natural waters. Carbon 42, 547 557. Ding L, Deng H, Wu C, Han X, 2012a. Affecting factors, equilibrium, kinetics and thermodyn amics of bromide removal from aqueous solutions by MIEX resin. Chemical Engineering Journal 181 182, 360 370. Ding L, Lu X, Deng H, Zhang X, 2012b. Adsorptive removal of 2,4 Dichlorophenoxyacetic Acid (2,4 D) from aqueous solutions using MIEX resin. Indus trial & Engineering Chemistry Research 51, 11226 11235. Ding L, Wu C, Deng H, Zhang X, 2012c. Adsorptive characteristics of phosphate from aqueous solutions by MIEX resin. Journal of Colloid & Interface Science 376, 224 232. Edzwald, J.K., Tobiason, J.E., 2011. Chemical Principles, Source Water Composition, and Watershed Protection in: Edzwald, J.K. (Ed.), Water quality & treatment: A handbook on drinking water, 6th ed. McGraw Hill, Inc., New York. Fettig, J., 2005. Modelling the uptake of Natural Organic Matter (NOM) by different granular sorbent media. Journal Water Supply Research Technology AQUA, 54(2), 83 93. Humbert, H., Gallard, H., Suty, H., Croue J.P., 2005. Performance of selected anion exchange resins for the treatment of a high DOC content s urface water. Water Research 39, 1699 1708. Jacangelo, J.G., DeMarco, J., Owen, D.M., Randtke, S.J., 1995. Selected processes for removing NOM: and overview. Journal AWWA 87 (1), 64 77. Karanfil T., Kilduff J.E., Kitis M., Wigton A., 1999. Role of granula r activated carbon surface chemistry on the adsorption of organic compounds. 2. Natural organic matter Environmental Science & Technology 33, 3225 3233. Kilduff, J.E., Karanfil, T., Chin, T. P. Weber Jr., W.J., 1996. Adsorption of natural organic poly electrolytes by activated carbon: a size exclusion chromatography study. Environmental Science Technology 30 (4), 1336 1343. Kunin, R., Suffet, I.H., 1980. Removal of humic material from drinking water by anion exchange resins. In: McGuire, M.J., Suffet, I .H. (Eds.), Activated Carbon Adsorption of Organics from Aqueous Phase. Ann Arbor Science Publishers Inc., Ann Arbor, MI (Chapter 18). Lee, M.C., Snoeyink, V.L., Crittenden, J.C., 1981. Activated carbon adsorption of humic substances. Journal AWWA 73 (8), 440 446.
60 Narabaitz, R., McEwen, J., 2012. Electrochemical regeneration of field spend GAC from two water treatment plants. Water Research 46 4852 4860. Newcombe, G., Drikas, M., Hayes, R., 1997. Influence of characterized natural organic material on activa ted carbon adsorption:II. Effect on pore volume distribution and adsorption of 2 methylisoborneol. Water Research 31, 1065 1073. Newcombe, G., Morrison, J., Hepplewhite, C., 2002. Simultaneous adsorption of MIB and NOM onto activated carbon. I. Characteris ation of the system and NOM adsorption. Carbon 40, 2135 2146. Pelekani, C., Snoeyink, V.L., 1999. Competitive adsorption in natural water: role of activated carbon pore size. Water Research 33, 1209 1219. Reckhow D.A., Singer P.C., Malcolm R.L., 1990. Chl orination of humic materials by product formation and chemical interpretations. Environmental Science Technology 24: 1655 1664. Singer, P.C., Schneider, M., Edwards Brandt, J., Budd, G.C., 2007. Magnetic ion exchange for the removal of disinfection by product precursors: pilot plant finds. Journal AWWA 99 (4), 128 139. Smith, E.H., 1994. Bench scale tests and modeling of adsorption of natural organic matter by activated carbon. Water Research 28 (8), 1963 1702. Sontheimer, H. 1976. The use of powdered activated carbon. In Translation of Reports on Special Problems of Water Technology, Vol 9: Adsorption. Report EPA 600/9 76 030, Cinicinnati, OH: USEPA. Sontheimer, H., Crittenden, J.C., Summers, R.S., 1988. Activated Carbon for Water Treatment, 2nd ed. D VGW_Forschungsstlle, Karlsruhe. Speth, T.F., 2001. In: Clark, R.M., Boutin, B.K. (Eds.), United States Environmental Protection Agency Document, EPA/600/R 01/110, December 2001, 9 1 9 30. Summers, R., Hooper, S., Solarik, G., Owen, D., Hong, S., 1995 Ben ch scale evaluation of GAC for NOM control. Journal AWWA 87 69 80. Summers, R.S., Roberts, P.V., 1988. Activated carbon adsorption of humic substances: II. Size exclusion and electrostatic interactions. Journal Colloid Interface Science 122(2), 382 397. T an, Y., Kilduff, J.E., Kitis, M., Karanfil, T., 2005. Dissolved organic matter removal and disinfection byproduct formation control using ion exchange. Desalination 176, 189 200.
61 Treybal, R.E., 1980. Mass Transfer Operations. McGraw Hill Publishing 3rd ed Uyak, V., Yavuz, S., Toroz, I., Ozaydin, S., Genceli, E.A., 2007. Disinfection by products precursors removal be enhanced coagulation and PAC adsorption. Desalination 216, 334 344. Velten, S., Knappe, D., Traber, J., Kaiser, H., von Gunten, U., Boller, M. Meylan, S., 2011 Characterization of natural organic matter adsorption in granular activated carbon adsorbers. Water Research 45 3951 3959. Walker, K.M., Boyer, T.H., 2011. Long term performance of bicarbonate form anion exchange: Removal of dissolved organic matter and bromide from the St. Johns River, FL, USA. Water Research 45, 2875 2886 Wang, D., Xing, L., Xie, J., Chow, C.W.K., Xu, Z., Zhao, Y., Drikas, M., 2010. Application of advanced characterization techniques to assess DOM treatability of mic ropolluted and un polluted drinking source waters in China. Chemosphere 81, 39 45. Weber, W.J., DiGiano, F.A., 1996. Process Dynamics in Environmental Systems. Wiley, New York.
62 BIOGRAPHICAL SKETCH The author began research with Dr. Treavor Boyer during th e summer of 2009, comparing anion exchange and coagulation for DOC removal from landfill leachate with Sarah Comstock. She conducted her own research with Dr. Boyer with the University Scholars Program during the summer of 2010, using MIEX to remove DOC fr om nanofiltration membrane concentrate. She presented this work as an oral presentation at American Water Works Association (AWWA) Water Quality and Technology Conference 2010 in Savannah, GA and as a poster at the Environmental Engineering Poster competit ion and University Scholars Poster Forum. She received a Bachelor of Science in Environmental Engineering from University of Florida in December 2011. She presented this work at as a poster at American Water Resources Association Annual Conference 2012 in Jacksonville, st Annual Engineering School of Sustainable Infrastructure and Environment Poster competition where she won first place in the graduate student section. She presented this work as an oral presentation at AWWA Annual Conference and Exposition 2013 in Denver, CO.