PILOT PROGRAM FOR THE EVALUATION OF NANOFILTRATION MEMBRANES PREPARED BY: WILMINGTON, MA ON UF PERMEATE

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1 PILOT PROGRAM FOR THE EVALUATION OF NANOFILTRATION MEMBRANES ON UF PERMEATE PREPARED BY: KOCH MEMBRANE SYSTEMS, INC. 850 MAIN STREET WILMINGTON, MA NANOPILT. D157

2 INTRODUCTION This progrm will outline the experimentl procedures nd guidelines required to perform systemtic evlution of spirl wound nnofiltrtion modules. These experiments re designed to yield the necessry dt to mke full-scle system projections. OBJECTIVES The three most dnportnt prmeters in ny filtrtion process evlution re permete flux rtes, rejection of desired species, nd clenbility. These prmeters will be exmined with respect to concentrtion; operting pressures nd flow rtes; nd length of processing. The gols of pilot progrm re to: Demonstrte successful performnce on long-term processing nd repetitive clening. Develop flux nd rejection dt s function of operting conditions. Optimize processing conditions nd clening procedures. Evlute effects of long-term processing t elevted pressures. Reminder: RO membrne must never be exposed to ny chlorine whtsoever s instntneous membrne degrdtion will occur.

3 2. EXPERIMENTAL OPERATION SimDle Btch ODertion Simple btch opertion (Figure 1) consists of strting with full feed tnk nd concentrting down s fr s possible (or to the desired endpoint). The btch size is limited by the size of the feed tnk. Simple btch opertion is used to generte dt on rejection nd on flux versus concentrtion, verge pressure, flow rte, nd time. Btch opertion is useful for determining if initil membrne selection is pproprite. Modified Btch ODertion Prohibitive tnk size would be required to run high volumetric reductions in simple btch mode of opertion. However, by using modified btch mode (Figure 2), the sme dt cn be provided with much more resonble tnk size. By monitoring the rte of permetion, it is possible to continuously dd fresh feed s permete is removed. With this. rrngement, flux versus concentrtion dt from 1X to the desired endpoint cn be generted. Other prmeters to be exmined will be the effects of verge pressure, flow rte, nd time (fouling) on flux nd rejection.

4 3. Feed nd Bleed Opertion Feed nd bleed opertion minimizes the required tnkge for given process but does this t the expense of membrne re. In this mode of opertion, 1X feed is continuously dded to the system nd concentrte t the desired concentrtion is continuously bled off. These systems re generlly designed s ttstges-in-serieslt (Figure 3). In this mode, the concentrte from one stge becomes the feed for the next. The reson for this reltes to economics. Consider hypotheticl cse where the fluxes re high t 1X nd decrese to low level t the end point of 1OX. If we design one lrge stge to concentrte to lox, tht stge would operte t bout lox, resulting in low flux rtes (nd poor efficiency). If we do the sme design in two stges, we my find the first stge opertes round 4X (moderte) nd the lst t 1OX (low). If we design t three stges, the concentrtions might be 2X (high), 5X (moderte), nd 1OX (low). More nd more stses will result in better efficiency from membrne stndpoint; however, t some point the dditionl cost of the dded stses will offset the sreter membrne efficiency. KMS hs vst experience in determining the optimum point for prticulr process. This mode cn be stisfctorily simulted with btch nd semibtch piloting.

5 KOCH MEMBRANE SYSTEMS, INC. CROSS FLOW MEMBRANE F'ILTRATION FIGURE 1- FEED TANK CROSS-Fi OH MEMBRANE fri r.r RECIRCULATION PUMP BATCH PROCESS FIGURE 1-b t PERMEATE FEED TANK CROSS-FL OW MEMBRANE f I1 TER RECIRCULATION PUMP MODIFIED BATCH PROCESS I FIGURE 1-c FEED TANK STAGE 1 STACE 2 1 R " E FEED AND BLEED PROCESS

6 4. EXPERIMENTAL OBJECTIVES Flux s Function of Concentrtion (J vs Cf) Flux will typiclly decrese with incresing concentrtion of the rejected species. This dt cn be gthered directly by tking feed smples nd mesuring solids, or indirectly by monitoring flux with respect to volumetric reduction. Flux s Function of Averqe Amlied Pressure (J vs Pv) Flux rtes will generlly increse with incresing pressure. Stndrd ultrfiltrtion membrne systems operte in the rnge of 40 to 80 psi verge pressure. Nnofiltrtion membrne systems my operte from 150 psi up to 600 psi verge pressure. Flux rtes t higher pressures re often limited due to resistnces t the boundry lyer nd other membrne surfce phenomen, s well s the possibility of compction of the membrne itself. Averge pressure excursions will be performed t 1X concentrtion nd t the highest ttinble concentrtion. During these excursions, it is importnt to mintin concentrtion, temperture, nd flow rte constnt. Rejection s Function of Averqe Amlied Pressure (R vs Pv) The min incentive for evlution of nnofiltrtion membrnes t higher pressures is for incresed retention over ultrfiltrtion membrnes. Rejection dt will be collected during pressure excursions to determine optimum operting conditions s the rejection properties of the membrne will be influenced by pressure.

7 5. Flux s Function of Flow Rte (Pressure DroDI(J versus API Flux rtes nd stbility re often controlled to lrge degree by the flow rte cross the membrne surfce. The boundry lyer formed close to the membrne surfce by the retined species cn offer lrge resistnce to permete flux. The extent of this resistnce cn often be effectively reduced by incresing the flow velocity cross the membrne surfce. The flow rte cn be monitored by the pressure drop since pressure losses re proportionl to fluid velocity. Flow rte excursions will be crried out t the sme concentrtions s the J versus P excursions. During these excursions, it is importnt to mintin concentrtion, temperture, nd verge pressure constnt. Flux s Function of Time (J versus TI Flux rtes cn decrese with time on some strems due to fouling. During continuous processing this is esy to evlute by prepring plots of flux versus time. During btch or modified btch opertion, runs of different feed volumes cn be processed to the sme finl concentrtion nd the influence of time on flux cn be exmined. Exmple: Process 50 gllons to 5X, then process 100 gllons to 5X; compre J versus Cf curves.

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9 6. CLEANING PROCEDURES Clening procedures re specific to ech ppliction nd the effectiveness of the following suggested method must be exmined s prt of the pilot study. Two fctors should be considered when evluting the clening procedure: Did the wter flux return to n pproprite level, nd ws the rejection of the membrne ltered in ny wy? Stndrd Shutdown 1. Drin system of feed. 2. Fill tnk with wrm, good-qulity wter (120 F). 3. Purge system of concentrte. 4. Thoroughly flush permete side of modules. 5. Tke wter flux. 6. Perform stndrd clening. Stndrd Clenins The following stndrd clenings should be used s needed for single four-inch spirl. Alkline clening solution: Removl of orgnic foulnts 1. Fill tnk with 100 F (40 C) soft wter. 2. Recirculte t psi inlet nd 9-10 gpm recircultion flow (FI2). Add 0.2% ALD. Add sodium hydroxide to djust the ph to Run for minutes 3. Flush system with wrm soft wter (100"F, 40 C).

10 7. 4. Tke wter flux, drin. 5. If flux is low, proceed to the cidic clening. Acidic clening solution: Remov.1 of inorgnic foulnts 1. Fill tnk with 100 F (40 C) soft wter. 2. Recirculte t psi inlet nd 9-10 gpm recircultion flow (FI2). Add one of the two cids listed: ) 0.1% solution phosphoric cid (up to 0.5% my be used depending on need). b) 2% solution citric cid. 3. Flush system with wrm soft wter (100 F) (40 C). 4. Tke wter flux, drin. Wter Flux 1. Strt system on soft wter t Pin = 105 psi, Pout = 95 psi. 2. After bout five minutes, record inlet nd outlet pressures, temperture, nd wter flux. 3. Stndrdize wter flux ccording to the following formul: S t ndrdiz ed 250 psi Averge Pressure Wter = [Recorded Flux] x x TCF*. Flux Averge System Pressure *Temperture correction fctor NANOPILT. D157

11 ~ ~ ~~ ~,. WATER FLUX TEMPERATURE CORRECTION FACTOR (F)* Flux (25 C) - Flux (T'C) x F or Flux (77 F) - Flux (T'F) x F Temp Temp (OF) ("C) F Temp Temp (OF) ("C) F Temp Temp (OF) ("C) F Bsed on wter fluidity reltive to 25 C (77 F) fluidity vlue. F - (PT0C/25"C), or F (PT F/77"F) NANOPILT. D 157

12 9. WATER QUALITY GUIDELINES o Turbidity less thn 1.0 NTU o Iron less thn 0.3 ppm o Mngnese less thn 0.05 ppm o Aluminum less thn 1 ppm o Clcium less thn 10 ppm o Silic less thn 10 ppm o Freedom from prticulte mtter such s rust, scle, flke mteril, sndy grnulr mteril, slurries, scum, lge. Softened wter or evportor condenste is generlly cceptble for clening nd flushing ultrfiltrtion membrnes.

13 J 10. EXPERIMENTAL PROGRAM Initil Membrne Clening nd Rejection Verifiction 1. Perform stndrd lkline clening to remove residul preservtive nd to evlute new membrne wter flux. Preservtive: 0.02% Pentchlorophenol solution. 2. Evlute initil slt rejection s bseline reding to determine if subsequent clenings or process conditions re detrimentl. -- Prepre 0.5% NCl solution. Recirculte through system t n verge pressure of 350 psi t 25 C. -- Collect flux dt nd conductivity vlues on the permete nd on the concentrte sides. -- Determine percent NCl rejection s follows: % Rejection = (1 - Permete Conductivity/Feed Conductivity) x 100 The following mrkers hve lso been used to evlute this membrne nd, if possible, one of them should be evluted long with the slt. Mrker RO % Rejection NF % Rejection Lctose 98% 98% MgS04 99% 98% NCl 98% 45%

14 11. ExDeriment #1: Short-term opertion in Feed f Bleed mode -- pressure nd flow excursions (- 8 hours) Operting Conditions: 330/270 psi Btch Size: Prefiltrtion: gllons 150 p 1. Recycle t 2X for 30 minutes to llow process to stbilize. Record flux decline. 2. Tke feed nd permete smples. 3. Begin concentrting. Clculte bleed rte required to chieve the following concentrtion fctors, bsed on the eqution given below: 3X, 5X, lox, 15X.** Allow 20 minutes to stbilize t ech concentrtion. Tke bleed nd permete smples. 4. Perform stndrd CIP nd record wter flux. **Bleed rte = Permete Rte/(X-1) where X = concentrtion fctor. NANOPILT. D 157

15 12. Exrseriment #2: Long-term opertion in Modified Btch mode (- 48 hours) Refill the feed tnk with 1X feed. Strt the system nd run pproximtely 15 minutes on totl recycle. Record stndrd dt on the log sheet nd tke n initil feed nd permete smple. Additionl smples will be tken t pproximtely 2X, 3X, 4X, 5X, lox, nd finl concentrtion s the vrious concentrtions re reched, or t minimum every 6 hours. Perform excursions 10 minutes between Pin/Pout Dsi) 330/ / / / / / / / /270 s shown below. Allow flux to stbilize bout ech setting before recording dt. Pvq Delt P (wid Do not exceed 10 gpm on recircultion flowmeter. Begin modified btch opertion. Direct the permete to drin nd dd 1X feed t rte equl to the permetion rte. Agin, monitor system performnce every 30 to 60 minutes nd record the stndrd dt. Continue dding 1X feed until pproximtely 50,000 pmho conductivity is reched in the RO process tnk. "Btch down" the RO process tnk. Stop 1X feed nd continue to remove permete. As the hlf level is reched in the tnk, tke smples nd record ll pertinent dt. As btchdown my be rpid, it is convenient to return the permete to the process tnk on 100% recycle while smples nd dt re collected. Perform pressure nd flow excursions s described erlier. At the end of the test, drin the tnk nd clen the system. Perform the stndrd clening nd record the clen wter flux. Additionl tests should be performed in the modified btch operting mode. Bsed on the previous tests, optimum conditions of verge pressure nd flow should be used.

16 13. Experiment #3: Long-term opertion in Feed & Bleed mode t sme concentrtions (- 48 hours). OPTIONAL: For feed strems with consistent composition Operting Conditions: 330/ Recycle to llow flux to stbilize. Record flux decline. Tke feed nd permete smples. Set concentrtion to pproprite concentrtion fctor s determined from Experiments #1 nd #2 nd tke smples fter pproximtely one hour. Record dt every 1-2 hours. Tke smples pproximtely every six hours. Perform stndrd CIP nd record wter flux. Repet test. A minimum of two runs should be performed on ech feed strem tested. SmDlin Techniques Crefully lbeled smples of UF feed, concentrte, nd permete nd RO concentrte nd permete should be collected during the process runs t vrious concentrtion fctors. Glss smple bottles re preferred over plstic becuse the plstic will dsorb vrious smple constituents of interest (such s oil & grese). The nlyticl work should be performed promptly, preferbly the sme dy the smple is generted. Anlysis should include the following for feed, concentrte, nd permete smples: totl dissolved solids, suspended solids, conductivity, ph, oil & grese (if required), BOD (if required), COD (if required), nd mmoni (if required).

The Discussion of this exercise covers the following points: The open-loop Ziegler-Nichols method. The open-loop Ziegler-Nichols method

The Discussion of this exercise covers the following points: The open-loop Ziegler-Nichols method. The open-loop Ziegler-Nichols method Exercise 6-3 Level Process Control EXERCISE OBJECTIVE In this exercise, you will perform PID control of level process. You will use the open-loop step response method to tune the controller. DISCUSSION