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I N T E R N A T I O N A LFILTRATIONNEWSYour Global SourceMay/June 2011Volume 30 No. 3www.filtnews.comShow Report:Filtech 2011 - Largest EventSince BeginningFiltration – A GrowthMarket for Synthetic FibersMembrane Filter RatingRosedale ProductsSingle or Dual Stage MunicipalDrinking Water Filters

IN THIS ISSUEMay/June 2011, Vol. 30, No. 3Filtration | MarketingFiltration - A Growth Market for Synthetic Fibers 4Association | NewsAFS Dixie Chapter Spring Meeting Held in North Carolina 11Cover Story | Rosedale Products Inc.Single or Dual Stage Municipal Drinking Water Filters 12Membranes | TechnologyNew Methodology for “Hyperfine” Membrane Filter Rating 14Membranes | WastewaterNew Membrane Bioreactor System Eliminates MunicipalSurcharges with Onsite Wastewater Treatment Facility 22Filter | TestingMeasuring the Performance of a Filter Medium 28Show Report | Filtech 2011Filtech 11 - Largest Event Since Beginning 31Published byINTERNATIONALMEDIA GROUP, INC.6000 Fairview Road, Suite 1200Charlotte, NC 28210 USAPhone: +1-704-552-3705Email: info@filtnews.comInternet: www.filtnews.comCarol and Arthur Brown, FoundersKlaas DeWaal, Publisher and CEOAntoinette DeWaal, Associate Publisherand Vice PresidentEditorial DepartmentKen Norberg, Editor in Chief, Ken@filtnews.comAdrian Wilson, Intl. CorrespondentChen Nan Yang, China CorrespondentEditorial Advisory Board, See page 3Administration DepartmentBarbara Ragsdale, Barbara@filtnews.comCirculation DepartmentCherri Jonte, Subscribe@filtnews.comAdvertising Sales RepresentativesUSA:Joan Oakley, Joan@filtnews.comDebra Klupacs, Debra@filtnews.comEurope:Werner Meier, w.meier@iff-media-chJudy Holland, jholland@textilemedia.com -*$ %"*# % ,,, ")$,(%# %(" '%*)(%, &%') ") '() +$) $ $$ $ ")') %$ . '%,)'!) %' -$)) '(#'$ ")' ) $ $" %' *" ) *$ &"' $! $ )' ")'(Cover courtesy ofRosedale ProductsChina:Zhang Xiaohua, ifj-china@yahoo.com.cnPublication DataFiltration News (ISSN:1078-4136) is publishedbi-monthly by International Media Group, Inc.Printed in U.S.A., Copyright 2011.This publication has a requested and controlledsubscription circulation - controlled by the staff ofFiltration News; mailed bi-monthly as PeriodicalsPostage Paid (USPS 025-412) in Novi MI andadditional mailing offices.Filtration News is not responsible for statementspublished in this magazine. Advertisers, agenciesand contributing writers assume liability for allcontent of all submitted material printed andassume responsibility for any claims arisingthere-from made against publisher.Mailing Address for advertising,news releases and address changes:International Filtration NewsInternational Media Group, Inc.6000 Fairview Road, Suite 1200Charlotte, NC 28210 USAPhone: +1-704-552-3705Email: info@filtnews.comInternet: www.filtnews.comPOSTMASTER:Send address changes to:International Filtration NewsInternational Media Group, Inc.6000 Fairview Road, Suite 1200Charlotte, NC 28210 USA2 • June 2011 • www.filtnews.com

Editorial Advisory BoardEditorial Board ChairmanEdward C. Gregor,ChairmanE.C. Gregor & Assoc. LLCTel: 1 704 442 1940Fax: 1 704 442 1778ecg@egregor.comM&A, Filtration MediaHaluk Alper, PresidentMyCelx Technologies Corp.Tel: 770.534.3118Fax: 770.534.3117alper@mycelx.comOil Removal – Water and AirPeter S. Cartwright, PECartwright Consulting Co.cartwrightconsul@cs.comMembranes, RO,UltrafiltrationWu ChenThe Dow Chemical CompanyTel: 1 979 238 9943Fax: 1 979 238 0651Process Filtration (liquid/gas)Equipment and MediaPeter R. Johnston, PETel/Fax: 1 919 942 9092ddandp3@aol.comTest proceduresJim JosephJoseph MarketingTel/Fax: 1 757 565 1549josephmarketing@verizon.netCoolant FiltrationDr. Ernest MayerDuPont Co.Tel: 1 302 368 0021Fax: 1 302 368 1474ernest.mayer@usa.dupont.comGeneral Solid/Liquid Separationsin All AreasRobert W. McilvaineTel: 1 847 272 0010Fax: 1 847 272 9673mcilvaine@mcilvainecompany.comwww.mcilvainecompany.comMkt. Research & Tech. AnalysisHenry Nowicki, Ph.D. MBATel: 1 724 457 6576Fax: 1 724 457 1214Henry@pacslabs.comwww.pacslabs.comAbsorbent Testingand TrainingBrandon Ost, CEOFiltration GroupHigh Purity Prod. Div.Tel: 1 630 723 2900bost@filtrationgroup.comAir Filters, Pharmaceuticaland Micro-ElectronicGregg PoppeThe Dow Chemical CompanyTel: 1 952 897 4317Fax: 1 942 835 4996poppeg@dow.comIndustrial Water, Power,and Membrane TechnologyDr. Graham RidealWhitehouse Scientific Ltd.Tel: +44 1244 33 26 26Fax: +44 1244 33 50 98rideal@whitehousescientific.comFilter and Media ValidationAndy RosolGlobal Filtration Products Mgr.FLSmidth Mineralsandy.rosol@flsmidth.comTel: 1800 826 6461/1 801 526 2005Precoat/Bodyfeed Filter AidsClint ScobleFilter Media Services, LLCOffice: 1 513 528 0172Fax: 1 513 624 6993cscoble@filtermediaservices.comFabric Filters , Filter Media,Baghouse MaintenanceTony ShucoskyPall MicroelectronicsTel: 1 410 252-0800Fax: 1 410 252-6027tony_shucosky@pall.comCartridges, Filter Media,MembranesMark VanoverBayOne UrethaneSystems LLCMarketing ManagerTel: 1- 314-591-1792Email:mark.vanover@bayone.comPolyurethane SystemsScott P. YaegerFiltration and SeparationTechnology LLCTel/Fax: 219-324-3786Mobile: 805-377-5082spyaeger@msn.comMembranes, New Techn.Dr. Bob BaumannAdvisory BoardMember Emerituswww.filtnews.com • June 2011 • 3

Filtration | MarketFiltration – A GrowthMarket for Synthetic FibersBy Edward C. Gregoror the information technology marketwith computers, iPods, cell phones,biotechnology and all the other growthindustries. However, few other manufacturingindustries hold a candle to filtrationsconsistent year-over-year growthand predictable profitability.INDA, the principal nonwoven industrytrade association in the USA,identified North American filtrationnonwoven roll good sales at $735 millionin 2007, as the largest nonwovenmarket segment in North America. In2011, sales are now approaching $800million in spite of the economic environment.Few would image that nonwovenfabrics for filtration marketshave actually surpassed hygiene ormedical drapes and gowns sales. Oneonly need look at what Fortune 500companies have and are paying to acquirefiltration and separations companiesin terms of multiples tounderstand the magnitude and ongoingstrength of the filtration industry.INDUSTRY MEGA TRENDSLeading trends include:Filter Cartridge from Meltblown Nonwoven Fabric Filter with FluoropolymerFibers. Photo courtesy of Pall Corporation.It may surprise many to learn that thefiltration and separation industry isa growth industry and syntheticfibers have played a major role in its success.Over the last 20 years the filtrationand separations industry has grown at asteady rate of 2-6 percent per year beyondthe economy, whether the economyis up, down or stagnant. Certainmembrane market segments have a historicalgrowth of 5-10 percent, whereasothers are growing at 25 percent per year.Synthetic fibers for use in filtration maynot be as glamorous as medical devices4 • June 2011 • www.filtnews.com• Finer filtration, which continuouslycreates opportunities for wider useand refinements of filtration mediaand new materials of construction• Steady predictable long-term growthfor most filter makers and suppliers• Consolidation has accelerated in thelast 4-5 years• Fibers are used widely in filtrationmedia• Environmental consciousness asusers seek solutions to containcontamination• One world business as technologygrows and easily transcends borders;including emerging markets

Filtration | Market• Legislation and regulatory controlsare increasing by the United StatesCongress, State and local officialswith enforcement by the EPA andother agenciesLEGISLATING GROWTHTraditional drivers of industrygrowth revolve around the need toimprove product quality in manufacturingprocesses, prevention of undesirablecontainment and pollutionbefore it occurs and remediation ofenvironmental damage. However, inrecent years, local, State and federalgovernment lawmakers and regulatorshave enacted legislation at an acceleratingrate. The CongressionalClean Air Act of 1990, with enforcementby the EPA, was the first majorpiece of broad legislation with realteeth. It provided new regulations forparticulate and other contaminantcontrol. Since then, there has beenenforcement of coal-based power generationfacilities including mercury,SOX and CO2 exhaust. Other legislationcontrols include oil and greasecontainment from parking lot stormwater runoff. Beginning in 2007,OEM diesel vehicle soot and NOxemissions were regulated in the USAand by most other major territoriesworldwide commencing in 2008. Enforcementaccelerates again in the2014 time frame with vehicle retrofitlegislation in California and implementationacross the USA for use intug boats, locomotives, etc. Separately,the United States EPA enforcementof Superfund Site cleanup andother less publicized enforcementshave also become important factors.In addition to traditional industrygrowth, including emerging countries,legislation has become an importantfactor and best friend of thefiltration and separations industry.FUNDAMENTAL CHARACTERISTICS• Industry growth out-paces theeconomy by 2-6 percent per yearwith certain segments perenniallygrowing at higher levels• Many filtration and separationcompanies achieve 25-50 percentgross profit margins• The customer base is extremelydiversified with over 30 majormarket segments• It’s still largely a razor blade typebusiness with extensive replacementof filters• Liquid filtration and separation, as arule, tends to be more profitable thanair or gas filtration, although thereare exceptions in specific situations• Product cycles are long, often 10 - 20years and more• Upstream product development withcustomers is common, especially forhigh-performance end-uses• The better performing companies6 • June 2011 • www.filtnews.com

Filtration | Markethousings, piping and othersystem materials and one beginsto realize why polymercompanies have paid attentionto opportunities in thismarket.Baghouse Filters from Hydroentangled Nonwoven using PET Fibers.Photo courtesy of PGI Nonwovens.have been acquired at 8-16 timesEBITDA over the last 10 years.MEDIA - THE HEART AND SOULMicroporous membrane filtrationmedia roll stock is a $2.5 - $3 billiondollar worldwide industry, dependingupon whose report one buys. Membranemedia is but one component andabout 10 percent of the cost of an allplasticfilter cartridge, yet uses 2 layersof nonwoven fabric as pleat support forevery one layer of membrane in the filtercartridge. This has an enormous impacton the use of nonwovens andhighlights synthetic fiber contributionsto the filtration and separations industry.Synthetic nonwoven filtrationmedia roll stock sales are approximately$2 billion dollars worldwide.This value does not include in excess of$1 billion worldwide for cellulosic wetlaidfiltration media, typically used inautomotive and truck engine air intake,fuel and oil filters and a variety of otherapplications. Add in the hundreds ofmillions if not billions of dollars in syntheticmonofilament and multifilamentyarns, roving and staple fibers, plasticcartridge support frames, end caps,8 • June 2011 • www.filtnews.comPOLYPROPYLENE FIBERSPolyolefin, and in particular,polypropylene, is one ofthe three main workhorsesynthetic fibers of the industry.Polypropylene fibers arewidely specified in filtrationmedia where chemical or solventresistance is important.Polypropylene monofilamentand multifilament woven fabrics,meltblown, spunbondand thru-air bonded fabricsand spray spun (meltblown)cartridges are widely usedwith a variety of constructionsin coolant filtration, paintspray booths, demisters, filter presses,spring wound cartridges, dewateringbelts and meltblown fabrics for vacuumcleaner bags. Wetlaid polypropylenefabrics are used as membrane substratesfor certain cleanable RO/UFmembranes spiral wrap modules.Polypropylene is a leading polymer andwidely used fiber component of HVACair filters, taking advantage ofpolypropylene’s negative triboelectricproperty for enhanced particle capture.POLYESTER FIBERSPolyester fibers are used primarily innonwoven fabric and monofilamentwoven fabric for a variety of applications,including filtration media municipalsludge dewatering to criticalmedia applications from open heart bypasssurgery to hernia patches. Polyesterand co-polyester fibers in the formof a wetlaid substrate are used as supportmaterial for RO/UF membranesand/or binder fibers combined with celluloseor glass fibers for specialty applications.Polyester yarns dominateknitted channel fabrics in spiral woundmodules. On the nonwoven fabric side,polyester-based media is used in swim-

Association | NewsAFS Dixie Chapter Spring Meeting Held in North CarolinaBy Ed GregorThe Dixie chapter of the AmericanFiltration and SeparationsSociety (AFS) held a two-dayspring chapter meeting and conferenceMarch 9-10 at Purolator-Facet in Greensboro,North Carolina. The event wasmarked with a good dose of networking,camaraderie and the opportunity to makenew industry acquaintances in the best ofsouthern fashion. The event had 12 presentationsover both days covering thetopic of Self-Cleaning, Cleanable andReusable Filters for Liquids and Gas.Chapter members went on a very informativetour of the Childress Wineryand had a unique educational experience.Interestingly, participants learned how filterpresses are being replaced by ceramictangential (crossflow) filtration in winemaking, even with smaller wineries, suchas Childress, who share the equipmentduring the season. The head wine makerwas every bit as much of a “filter man” asanyone of the visitors, with his in-depthknowledge of the vast variety of industryfilters and filtration processes. This obviouslycontributed greatly to the experienceand appreciation of the tour andwinemaking process. Of course, few ofthe participants left without a chance totaste the wine and a visit to the wine shop,taking home the fruits in a bottle or two.A networking reception followed laterin the day with a Dixie chapter meetingincluding the election of three new officersgoing forward: Todd Furbee, DeltaPure Filtration as Dixie chapter president;Rob Prichard, Fiberweb, chapter vicepresident; and Brad Zeigler, Sefar, chaptersecretary/treasurer. An in-depth slide presentationfollowed on the topic of reusablefiltration media, covering six of the mostcommon choices and end use market opportunities.For those who thought theindustry was largely made up of disposablefilters, a dose of just how broad theindustry is and how many opportunitiesexist for higher-margin business wasgleaned, and perhaps a new mindset fromMembers of the Dixie chapter of the AFS at the spring meeting.the comments after the meeting.On the second day, participants met inthe conference room at Purolator-Facetwith 11 presentations on reusable and“green” filtration media, filters and systemsincluding insight into two brandnewemerging technologies, beyondtraditional industry offering with plenty ofchances for Q&A. One of the speakers ranfor the U.S.House of Representativesin2010, but lost, althoughhe said hewould try againin 2012. Most attendeesleft thetwo days with anumber of newprofessional contactswith severalasking about futureDixie chaptermeetingsand/or AFS CorporateSponsorshipfor theirc o m p a n i e s ,which was an allaroundpositivesign of success.Special thanksgo to exiting officers– Cecil Baty,H.C. Warner,chapter president;Don Olds,Olds Filtration,vice president;www.filtnews.com • June 2011 • 11and George Stone, Jack Daniels (retired),secretary/treasurer – for their dedicated effortsand stewardship over the years inkeeping the Dixie chapter strong and oneFNof the leading AFS chapters.AFS’ next calendar event is the 2011Fall Focus Conference in Houston, TX,October 17-20.For more information visit: www.afssociety.org

Cover Story | Rosedale Products Inc.Single or Dual StageMunicipal Drinking Water FiltersBy Dan Morosky, Rosedale Products, Inc.Most Americans take safe,contaminant-free drinkingwater for granted. Yetwaterborne disease outbreaks dooccur, with most directly related tocontaminated surface water orgroundwater with surface watersources. Violations of the Safe DrinkingWater Act affect millions of Americansthrough water provided to thepublic in restaurants, hotels, campgroundsand, of course, our homesfrom our municipal water system.Organisms such as cryptosporidiumand Giardia Lamblia can cause diarrhea,abdominal cramps, nausea, occasionalvomiting, and low-grade fever.Surface water is exposed to contaminationby cryptosporidium and Giardiafrom sewage and animal wastes.Additional organisms, such as Cryptosporidium,threaten water suppliesand produce diseases with serioussymptoms. Particularly at risk, are thevery young, the aged, and the immunologicallychallenged.The federal government has providedthe Surface Water Treatment Rule(SWTR), which specifically requiresthe control of Giardia in public watersupply systems. The SWTR establishesperformance criteria for water treatmentto ensure a 99.9 percent reductionof cysts in water supplies.Left to right: Single Stage Model 8302P; Single Stage Model NCO8135; Cutawayof 740 Cartridge –The “Y” pleat maximizes effective surface area.TWO FILTRATION SYSTEMSRosedale has developed two longlasting,effective water filtration systemsthat meet the SWTR and protocolsfor most states. The Single StageSystem is excellent for smaller applications.The Dual Stage System can be designedto filter water up to 500 GPM.12 • June 2011 • www.filtnews.comSingle Stage GiardiaCryptosporidium RemovalThe Model 8302P and NCO8135high-capacity filter housings offer anexceptional value in Giardia CryptosporidiumRemoval applications. Thesystem is approved for use in Oregonand has met all the EPA LT2 guidelines.The single housing and element providea large containment capacity combinedwith a rugged stainless steel designrated to 150 psi. It incorporates an eyenutcover that is easily removed, reducingtime spent on cartridge change-out.SINGLE STAGE FILTER ELEMENTSPS-740-PPP-356 elements are manufacturedin a unique “Y” pleat arrangementthat optimizes physical size andmaximizes effective surface area. Thelarge surface area provides a low fluidflux rate maximizing dirt containment.This provides a 3 LOG cryptosporidiumremoval (see chart) when usedalone. The optimum flow rate for thesystem is 10 gallons per minute (GPM).The element fits into the RosedaleNCO8135 housing or can retrofit existing8302P housings with an adaptorbasket. The end caps are heat sealedfor high efficiency performance. Theo-ring seal insures sealing and eliminatesbypass.

Retrofit Current SitesExisting installations using theRosedale 8302P and PS-520-PPP-241or GLR-PO-825-2 can easily convert toa single housing by installing the PS740 adaptor basket.This is accomplished by replacingthe perforated filter basket with theadaptor. The solid side basket acceptsthe new PS 740 cartridge and directsthe flow through the unit.Typical application, from left to right (below): Optional Roughing Pre-Filter Bag, Filter PS-520-PPP-241, Final Filter GLR-PO-825-2.Dual Stage GiardiaCryptosporidium RemovalRosedale has developed an effectivewater filtration system that meets theSWTR and protocols for most states. Twostage systems are approved in California,Washington, Oregon, Vermont, Maineand Minnesota. This system offers adual-stage design that filters out largercontaminants before filtering out disease-producingmicroorganisms. Thisextends the life of the element that filtersout the Giardia and Cryptosporidium.The system consists of two highqualityRosedale Model 8 housings(pressure vessels), placed in series.• The first stage is fitted with aPS-520-PPP-241 bag/cartridge.• The second stage is Rosedale’sGLR-PO-825-2 bag/cartridge.An optional third Roughing Filter isrecommended, and helps extend elementlife for all the filters (see TypicalApplication photo).This provides a 2 LOG cryptosporidiumcredit (see chart) whenused in tandem. The optimum flow ratefor the system described is 13 gallonsper minute (GPM).DUAL STAGE FILTER ELEMENTSPre-filter (Optional)All graded-density bags are constructedof nine-layers of polypropylenemicro fibers and standard fibersthat are variably calendered. Heavydutyhandles are sewn and turned insideout to avoid leakage and enhancetheir pressure capacities.Final Filter (2 Choices)1. The Rosedale GLR-PO-825-2 elementhas 26 layers of high-efficiencypolypropylene micro fiber material, encasedin a rigid support cage. The initiallayers are pre-filtration levels, while thenext several layers filter the cystpathogen itself. The final barriers preventany material from migrating intothe effluent. All GLR units have a speciallydesigned gasket to assure a bypass-proofseal. All seams and joints areheat sealed to prevent leakage. The inside-outflow design traps contaminantson the inside, reducing thepossibility of downstream contaminationduring change-out and simplifyingthe service process. NSF 61 listed.2. The PS-520-PPP-241 filters aremanufactured in a “Y” pleat arrangementthat optimizes physical size andmaximize effective surface area. Thelarge surface area provides a low fluidflux rate maximizing dirt containment.This means element life is extended(NSF 61 listed).Rosedale manufactures filtration systemsfor larger applications that can filterwater up to 500 GPM. Multiple designsFNare available to meet clients needs.www.filtnews.com • June 2011 • 13For more information contact:Rosedale Products Inc.P.O. Box 10853730 West Liberty RoadAnn Arbor, MI 48106Tel: 1-800-821-5373, 1-734-665-8201Fax:1-734-665-2214Website: www.rosedaleproducts.com

Membranes | TechnologyNew Methodology for “Hyperfine”Membrane Filter RatingBy Tony Shucosky, Patrick Connor and Takehito Mizuno, Pall MicroelectronicsThere are a number of industriesin which microporousmembrane filtration is an enablingtechnology. Membrane filtersallow users to remove microscopic“killer” particles that would otherwisebe detrimental or even destructiveto their processes. A primeexample is leading edge integratedcircuit production. Particles as fine as20 nanometers i can intrude fromprocess streams contacting semiconductorwafers and potentially causingfailure of chips produced from thesewafers. Manufacturers of filters intendedfor these processes must producefilters capable of capturing suchfine particles, as well as providingsome quantitative indication of captureefficiency at these small sizes.The current state of particle countingtechnology exhibits suitable sensitivityonly down to about 30 nm. Thislimits the extent to which membraneproducers can provide a product witha reliable rating finer than 30 nm.Membrane producers have commonlyaddressed this obstaclethrough the use of indirect methodsof assessing particle retention below30 nm. For example, determinationof the pressure (usually referred to asthe “KL” value) at which liquid retainedin the porous structure by surfacetension is expelled has beenshown to correlate with retention ii .Other methods include determinationsof pore size distribution byporosimetry or actual measurementsof pore size by microscopy iii,iv . Evenwhere there is a sound physical rationalefor such methods, they areonly capable of providing a rough,qualitative indication of the size ofparticle the membrane can capture.There is a need to develop new techniquesthat circumvent the limitationsof particle counters and permitquantitative filter rating. This paperdescribes a new technique that candemonstrate quantitative membraneretention of particles as fine as 10 nmusing colloidal gold as a model particlefor challenging the membrane.This new method makes use ofthese key facts regarding colloidalgold:1. It is available in a variety ofsizes from < 5 nm to > 200 nm.2. It can be obtained as suspensionsof particles that are very nearlyspherical.3. As the colloid particles consistof essentially pure gold, their level insuspension can be measured accuratelyand over a wide dynamic rangeby inductively coupled plasma massspectrometry (ICP-MS).4. Suspensions of colloidal goldexhibit the necessary degree of colloidalstability required for testingmembrane retention.5. Because gold is conductive, it isnot necessary to apply a potentiallysize-altering conductive coating forelectron microscopy imaging, whereneeded.In developing this technique, PallMicroelectronics addressed the followingquestions that are importantwith respect to the testing and ratingof filters:• Do the particles exhibit therequisite uniformity of shape andsize required?• Does the technique showcomparability with other moreestablished techniques, e.g., theuse of single-sized PSL beads?14 • June 2011 • www.filtnews.com• Does the technique produceresults that are consistent withexpectations based on predictivetechniques, e.g., correlation ofretention to membrane KLvalues?• Is it possible to apply thetechnique reliably formembranes producedfrom various materials (e.g.,PTFE, polyamide, polyethylene)?• Can unintended adsorptive oragglomerative effects thatartificially enhance retentionefficiency be avoided throughidentification of proper testconditions?As described below, the company’sevaluation of the new technique hasdemonstrated its viability in terms ofall of these issues.EXPERIMENTALColloidal Gold: Materialsand CharacterizationAll of the testing described herewas conducted using colloidal goldobtained in various sizes (EMGCgrade: 10, 20, 30 nm), from BBI(Cardiff, U.K.). The actual particlesize distribution for the differentsizes used was determined using dynamiclight scattering (DLS, modelZetasizer Nano ZS, Malvern, Worcestershire,U.K.), with supplementalconfirmation of size and shape viafield emission scanning electron microscopy(FESEM, model S-5200, Hitachi,Tokyo, Japan). For referencepurposes, 33 nm PSL beads were obtainedfrom Duke Scientific (PaloAlto, CA, U.S.). Detection of the levelof elemental gold in suspensions ofcolloidal gold in deionized water wasdetermined using ICP-MS (model

HP-4500, Agilent, SantaClara, CA, U.S.), usinga standard solution ofchloroauric acid,HAuCl4 (Wako, Osaka,Japan) for calibration.Membrane TestingRetention testing offiltration membraneswas carried out using47 mm disks of varioustypes of media: polytetr a f l u o r o e t h y l e n e(PTFE) possessing ratingsof 20 nm and30 nm, high density polyethylene(HDPE) with ratings of 10 nm and30 nm, and nylon-6,6 rated at 20 nmand 40 nm. Where any medium isdesignated as having a rating finerthan 30 nm, this value was obtainedby extrapolating the correlation observedbetween KL value of themedium (in pure isopropanol) andsize rating as determined by quantitativecounting methods available at30 nm and larger. This is depicted inFigure 1. Rating of Membrane via Extrapolationof Curve for KL Data vs. Measured RetentionFigure 1 for the specific caseof PTFE.As necessary to achievewettability of the medium,disks were prewet with pureisopropanol and installed in astandard 47 mm disk holder. Thedisk holder was plumbed to a 10” filterhousing, functioning as a pressurevessel, which contained the colloidalgold suspension challenging themembrane. The disk holder, pressureFigure 2. Schematic of test set-upvessel, and all other wetted surfaceswere of perfluoroalkoxy (PFA) constructionto avoid potential electrochemicalinteractions that mightoccur between gold and metal surfaces.A constant pressure was main-

Membranes | Technologytained above the suspension in thevessel, adjusted to an appropriatelevel to allow a constant flow rate of5 mL/min to pass through the membrane,as established by monitoringthe weight of effluent from the membraneover time. The experimentalset-up is depicted schematically inFigure 2.The typical concentration of goldemployed for testing was 500 µg/L(500 ppb or 0.5 ppm), although additionaltests were run at lower concentrationswhere evaluation of theimpact of particle level (which can beeasily shown to be proportional tolevel of elemental gold for singlesizedparticles) on membrane retentioncharacteristics. The actual levelof elemental gold in the challenge solutionwas confirmed by ICP-MS. Inconducting actual tests, an initialvolume of effluent was discarded soas to ensure that results reflectedonly steady-state operation. Afterthis initial period, sufficient effluentwas collected for analysis of goldlevel by ICP-MS. Particle removal efficiencyis defined as:where Cpart. refers to the concentrationof particles in the influent to oreffluent from the filter membrane.For challenge testing involving single-sizedparticles, Cpart. can be replacedby CAu the level of goldmeasured by ICP-MS, as the parametersrelating Cpart. to CAu cancel in theequation above.Evaluation of Chemical Modificationof Colloidal Gold on Particle CaptureWith respect to HPDE andnylon-6,6 membranes, it was recognizedthat colloidal gold might exhibitexcessive adsorption on thesematerials, thereby leading to artificiallyhigh degrees of particle removal.To evaluate this aspect, aseries of colloidal gold suspensionswere prepared to which was addedbetween 0.5 and 10 ppm of two differentstabilizers known to be capableof bonding to the surface of thegold colloid particle. Based on informationgleaned from studies of thebehavior of colloidal gold in the presenceof various stabilizing ligands,Pall chose to evaluate the impact ofmercaptosuccinic acid (Wako) oncapture of colloidal gold by HDPE,and of 2-amino-2-hydroxymethyl-1,3-propanediol (Wako) for the caseFigure 3. Particle size distribution ofvarious sizes of colloidal gold andPSL beads16 • June 2011 • www.filtnews.com

Figure 5. Comparison of Removal Efficiencies of 20 nm PTFE Membrane Testedwith Various Concentrations of 30 nm Colloidal Gold and 33 nm PSL Beadsto exhibit more variation than thecorresponding size of colloidal gold,and even of the smallest size of colloidalgold employed. Collections ofcolloidal gold deposited onto asmooth surface, for each of the threesizes used, when imaged by FE-SEM,were found to be very uniform, withminimum deviation from spherical,as seen in Figure 4 (a,b,c).These evaluations demonstratethat colloidal gold as fine as 10 nm insize exhibits the requisite characteristicsin terms of approach toFigure 4. FE-SEM Images, 500kXmagnification, of 10 nm (top), 20 nm(middle), and 30 nm (bottom) colloidalgold particlesof nylon-6,6. Membrane testing withstabilized suspension of colloidalgold was otherwise conducted in thesame manner as described earlier.(Based on the known properties ofPTFE, it was not considered necessaryto employ stabilizers in tests involvingPTFE membrane.)RESULTS AND DISCUSSIONSize Distribution and Morphologyof Colloidal GoldAs depicted in Figure 3, the particlesize distributions of the colloidalgold suspensions used in this studyexhibit minimal variation from thevalues provided for them by the manufacturer,when analyzed by DLS. Inthis graph, the PSD of 33 nm PSLbeads has been overlaid, and is foundwww.filtnews.com • June 2011 • 17

Membranes | TechnologyFigure 6.RemovalEfficienciesfor VariousPTFEMembranesChallengedwith 20 nmColloidalGold18 • June 2011 • www.filtnews.commonodispersity of particle size anduniformity of particle morphology tobe used in a successful manner forthe rating of filtration membranesexpected to be capable of retentiondown to 10 nm.Comparison of Retention TestingUsing Colloidal Gold and PSL BeadsWhile the aforementioned limitationsin terms of suitable sub-30 nmPSL beads precludes comparison ofretention test results below that size,it was considered appropriate to establishcomparability of the gold colloidtechnique to the existing PSLmethodology that uses standard lightscattering particle counting instrumentationat 30 nm. For this comparison,PTFE medium which hadbeen assigned a 20 nm rating (per theKL correlative method mentionedearlier) was tested at various incidentparticle levels between about 1 108and 4 108 particles/cm2 of 33 nmPSL beads and 30 nm colloidal gold.As depicted in Figure 5, the twomethods yield essentially identicalresults, an indication that the goldcolloid method is suitable in terms ofquantitative testing of particulate retentionas compared to a well establishedtechnique.Comparability of Gold Colloid toPredictive TechniquesIt has been noted that in the absenceof definitive means of establishingthe quantifiable removal ofparticles of a given size, membraneproducers may utilize indirect techniquesto assign a size rating atwhich some reasonable reduction inlevel of particles ought to occur. Forsome of these methods, most especiallythe extrapolation of ratingbased on membrane KL, the strongdegree of correlation over a wide sizerange within which direct determinationof particle removal is possiblesuggests that predicted values oughtto have some validity, even if onlysemi-quantitative.PTFE membrane exhibiting a KLvalue suggesting that the membrane

Figure 7. Schematic representation of mercaptosuccinic acid (left) and2-amino-2-hydroymethyl-1,3-propanediol (right) covering surface of colloidalgold particles (CH bonds omitted for clarity)ought to provide reasonable retentionat 20 nm was subjected to testingwith a 500 ppb suspension of20 nm colloidal gold without the additionof any stabilizers. It was foundthat essentially 100 % removal wasachieved for the membrane assigneda 20 nm rating by indirect means.Furthermore, a PTFE membrane ofsimilar type, but possessing lower KLvalue and for which a rating of 30 nmhad been previously assigned usingdirect particle counting methodology,was also tested using 20 nm colloidalgold. In this testing, retention at20 nm was found to be 82%. Researchersadditionally tested twoother PTFE membranes that hadbeen assigned 30 nm ratings, but forwhich no information was availablewith respect to assignment of thisrating, with 20 nm colloidal gold retentionfound to be 71% and 55% forthese two membranes. These results,depicted in Figure 6, indicate thatthe colloidal gold technique producesresults that are in line with expectationswith respect to particleremoval of filters known by othermeans to possess intrinsically differentretention characteristics. Theyalso suggest that, there can be somevariation in actual performanceamong membranes given the samerating, even at 30 nm.been applied to the testing of PTFE,HDPE, and nylon-6,6 membranesthat have been assigned ratings finerthan 20 nm based on indirect techniques.For all of these media, it wasfound that the technique returned anindication of essentially complete retentionof the 10 nm (for HDPE) or20 nm (for PTFE and nylon-6,6) colloidalgold with which they werechallenged. These results indicatethat the technique is suitable for establishingretention characteristicsbelow 30 nm for various membranematerials known to have disparatechemical nature and morphology oftheir porous structure.Additionally, Pall compared the retentionof the 10 or 20 nm gold colloidparticles for two different gradesof each material. As shown inTable 1, the technique was capable ofshowing a difference between retentioncharacteristics for all three typesof material. This is further indicationof the general applicability of thetechnique for a variety of differentmembrane materials.For the HDPE and nylon-6,6 membranes,the listed value in Table 1. wasthe lowest observed in testing withvarious levels of stabilizer added, asdiscussed in the next section.Effect of Ligand Addition forAvoidance of the Impact of AdsorptionThe typical manner in which colloidalgold are prepared tends to produceparticles that will possess anadsorbed layer of citric acid, a conditionthat enhances their colloidal sta-Applicability of Gold Colloid Techniquefor Different Membrane MaterialsThe gold colloid technique haswww.filtnews.com • June 2011 • 19

Membranes | TechnologyFigure 8. Impact of addition of stabilizer on retention of colloidalgold particles smaller than assigned rating of membraneFigure 9. Impact of the addition of stabilizer on retention of colloidalgold particles of the same size as assigned filter ratingbility v . As such, no special additivesare necessary to maintain their suspensionin water. In spite of this colloidalstability away from themembrane surface, colloidal and interfacialchemical considerations predictthat for the sizes of particleencountered here, HDPE andnylon-6,6—but not PTFE—could beexpected to have some adsorptive effecton the colloidal gold particles.This condition might tend to resultin artificially high retention levels forparticles smaller than the assignedrating of a membrane.Various studies have shown thatthe surface properties of colloidalgold can be modified through the adsorptionof thiol or amino functionalgroups vi,vii,viii,ix . In evaluating severalpossible candidates it was found thatmercaptosuccinic acid (MSA) wouldbe the most appropriate stabilizer fortesting of the HDPE membrane,while 2-amino-2- hydroxymethyl-1,3-propanediol was suitable for testingof the nylon-6,6 membrane.Figure 7 provides a schematic representationof the adsorption of theseligands via sulfur and nitrogen, respectively,for the two compounds.As can be seen in Figure 8, the20 • June 2011 • www.filtnews.compresence of stabilizer had a significantimpact on retention, with 30 nmHDPE membrane and 40 nmnylon-6,6 membrane capable of exhibitingvery significant retention ofcolloidal gold smaller than the membranerating in the absence of stabilizer,but exhibiting a reduction in thepresence of stabilizer. On the otherhand, the 10 nm HDPE membraneand 20 nm nylon-6,6 membranes eachexhibited minimal reduction of retentionwhen challenged with 10 nm and20 nm colloidal gold, respectively, regardlessof the level of stabilizer presence.These findings are significant inthat they suggest that the techniquecan be optimized to minimize the unpredictableimpact of chemical effectsand provide a conservative indicationof capture that is primarily based onthe typical filtration mechanisms(e.g., sieving and inertial impaction).

CONCLUSIONSPall Microelectronics has developeda technique involving colloidal goldthat allows quantitative determinationof the removal by membrane of particlesas fine as 10 nm. This permits theassignment of size ratings below30 nm by a direct, operational measurementtechnique for today’s nextgenerationfiltration membranes. Thisrepresents a significant advancementover the indirect membrane ratingmethods that analytical limitationshave necessitated to this point for assigningratings finer than 30 nm. Thetechnique has been shown i.) to utilizea material available with the necessaryuniformity of size and shape to be appropriatefor the rating of filtrationmembranes, ii.) to provide resultsconsistent with expectations based onother direct and indirect methods, iii.)to be applicable to a variety of differentmembrane materials and iv.) to becapable of optimization to ensure thatadsorption effects that might lead toartificially high retention are addressed,thus providing a suitably conservativeindication of membrane ratingexpected to be based on typicalparticle capture mechanisms.FNFor more information contact:Tony Shucosky, Pall MicroelectronicsEmail: Tony_Shucosky@pall.comREFERENCESi) International Technology Roadmapfor Semiconductors, 2009 edition.ii) Pall, D.B., Kirnbauer, E.A,, andAllen, B.T., “Particulate retention bybacteria retentive membrane filters,”Colloids and Surfaces, 1(3-4), 235(1980).iii) Sanz, J.M., Jardines, D., Bottino,A., Capanelli, G., Hernandez, A., andCalvo, J.I., “Liquid–liquid porometryfor an accurate membrane characterization,”Desalination, 200(1-3), 195(2006).iv) Wyart, Y., Georges, G., Deumi, C.,Amra, C., and Moulin, P., “Membranecharacterization by microscopicmethods: Multiscale structure,” J.Membrane Sci., 315(1-2), 82 (2008).v) Kunze, J., Burgess, I., Nichols, R.,Buess-Herman, C., and Lipkowski, J.,“Electrochemical evaluation of citrateadsorption on Au(111) and thestability of citrate-reduced gold colloid,”J. Electroanalytical. Chem.,599(2), 147 (2007).vi) Schlenoff, J.B., Li, M., and Ly, H.,“Stability and self-exchange in alkanethiolmonolayers,” J. Am. Chem.Soc. 117(50), 12528 (1995).vii) Stoeva, S. I., Smetana, A.B.,Sorenson, C.M., and Klabunde, K.J.,“Gram-scale synthesis of aqueousgold colloids stabilized by variousligands,” J. Colloid. Interface Sci.,309(1), 94 (2007).viii) Chen, S., and Chimura, K.,“Synthesis and characterization ofcarboxylate-modified gold nanoparticlepowders dispersed in water,”Langmuir, 15(4), 1075 (1999).ix) Yonezawa, T., Yasui, K., andKimizuka, N., “Controlled formationof smaller gold nanoparticles by theuse of four-chained disulfide stabilizer,”Langmuir, 17(2), 271 (2001).www.filtnews.com • June 2011 • 21

Membranes | WastewaterNew Membrane Bioreactor SystemEliminates Municipal Surcharges withOnsite Wastewater Treatment FacilityBy Jim McMahonGolden Flake Snack Food’s membrane bioreactor in Birmingham, Alabama.The membrane bioreactor(MBR) system, designed andbuilt by ADI Systems Inc.,treats up to 400,000 gallons per day ofraw snack food wastewater using advancedmembrane bioreactor technologyfor liquid-solid separation,reducing suspended solids and biochemicaloxygen demand to less than 2milligrams per liter, eliminating$100,000 per month in municipalwastewater surcharges, and releasing250 gallons per minute of treated, filtered,oxygenated water into the localwatercourse ecosystemGolden Flake Snack Foods (GoldenFlake) located in Birmingham, Alabama,was faced with a tough decision;either come up with a solution to stemthe escalating municipal wastewatersurcharges it was being assessed, ormove its 300,000 square-foot snackfood processing plant out of the countyto stem the significantly rising costs. In1998, the plant was paying $800 to$1,000 per month to Jefferson Countyin surcharges for decanting its 100,000to 350,000 gallons of wastewater intothe county’s municipal sewer system.By 2008 that figure had escalated to$100,000 per month in surcharges forthe same daily discharged wastewater22 • June 2011 • www.filtnews.comflow rate, with county projections thatthe rate would most likely raise to$250,000 per month within the nextfive years.Given the fact that 68 percent ofGolden Flake’s 250-plus work forcelives within a 13-mile radius of theplant, the company preferred to keepits 80-year-old headquarters and mainmanufacturing facility in Birmingham,and find a solution to reduce or eliminatethe surcharges. This meant, inessence, getting off of the county sewersystem.The Alabama Department of EnvironmentalManagement, which sets

standards for wastewater regulationswithin the state, made it clear that ifGolden Flake could reach prescribedTSS (total suspended solids), BOD(biochemical oxygen demand), NH3-N(ammonia-nitrogen) and DO (dissolvedoxygen) concentrations, it couldreceive a discharge permit to conveytreated effluent directly into a creekthat runs along the perimeter of itsproperty, and bypass the JeffersonCounty sewer system altogether.GOLDEN FLAKE’S WASTEWATERThe Golden Flake plant manufacturesand distributes a full line of snackfood items, including potato chips, tortillachips, puffed corn, corn chips,cheese puffs, cheese curls, onion ringsand pork skins. Pork skins are its specialty,producing over a dozen varietiessuch as Louisiana Hot Sauce PorkSkins®, Hog Hides Pork Skins®, andWash Pot Style Pork Cracklins®.Golden Flake sells more pork skins inthe southeastern United States than anyother company.It is also well known for its extensiveline of potato chips, which is theproduct that Golden Flake wasfounded on in 1923. Dill Pickle Thin &Crispy Potato Chips®, and SouthernHeat Dip Style Potato Chips® are a fewof the 15 varieties it produces and distributes.The company’s popular brandsof Maizetos Tortilla Chips®, and TostadosMini Rounds® are highly recognizedbrands in the southeast U.S.In 2009, Golden Flake’s Birminghamfacility processed more than 20million pounds of snack foods totaling$120 million in sales, 95 percent ofwhich was distributed within 12southeastern states.The plant’s production mix of potatochips, corn chips and pork skins canvary, causing the raw snack food wastewaterto have varying strengths andconsistencies, with flow rates rangingfrom 100,000 to 350,000 gallons perday (gpd).All of the plant’s wastewater handledthrough its on-site wastewater treatmentfacility comes from the productionof snack foods (no sanitary sewageenters this system), mainly from theprocessing of potatoes and corn. Fromtheir arrival on site, the potatoes arecarried in a water flume to be peeledand sliced. The slices are then washedand put through deep fryers beforebeing packaged. The flume and washwater is drained daily and dischargedfor onsite wastewater treatment.Raw corn, for the production of cornand tortilla chips, is cooked in kettleswith water and lime to loosen and removethe husks, then soaked in vats toincrease the moisture content of thekernels. The kernels are then washed toremove impurities, milled, sheeted torun through ovens, deep-fried andpackaged. The water from theseprocesses is discharged after use for onsitewastewater treatment.Pork skins arrive at the plant in pelletform and go straight into deep-frying,then seasoning and packaging. Theplant has seven deep fryers that handleits various product types. The majorityof the spent cooking oil is trapped in anoil pit and removed before enteringwastewater treatment. But the fryers doneed to be boiled-out weekly con-www.filtnews.com • June 2011 • 23

FiltrationMergers, Acquisitionsand DivesturesGL Capital, LLCMembranes | WastewaterWe understand the nuances ofthe domestic and internationalfiltration industry and bringover 70 years of combinedbusiness, technical and financialexpertise. The current economicclimate is an ideal timefor sellers to locate buyersseeking to diversify and forbuyers to identify growth opportunitiesthrough acquisition.ADI-MBR system at Golden Flake, showing the pre-aeration tank.For a confidential conversation contact:Edward C. Gregor704-442-1940ecg@egregor.comP. John Lovell719-375-1564glcapital@comcast.net24 • June 2011 • www.filtnews.comtributing to the wastewater stream.Raw snack food wastewater ispumped through vibrating screens,which collect 15,000 to 20,000 poundsper week of large food particles. This organicmatter is collected and transportedupstate to be used as animal feed.From the time the facility was originallybuilt in the 1950s, the prescreenedwastewater leaving the plantwas received at a primary clarifier (forprimary sludge settling) with supernatantdischarged to the county sewersystem (Golden Flake is permitted torelease up to 400,000 gallons of wastewaterper day). The stagnant wastewaterin the primary clarifier was notaerated or covered and would produceoff-odors. The clarifier was locatedalong the edge of a street, where subsequentlya housing development hadbeen built, and the odor was becomingan issue with residents.“The wastewater being decanted tothe county sewer system had BOD andTSS concentration levels in the thousands,exceeding maximum surchargelevels” said David Jones, executive vicepresident of operations for GoldenFlake. “As our surcharges continued toescalate, we began looking for a treatmenttechnology that could not onlyhandle our high-volume peak flows of350,000 gpd, but also produce an effluentthat was below the Alabama Departmentof EnvironmentalManagement’s maximum allowable dischargeconcentration limits for BOD,TSS, NH3-N and DO.”ENGINEERING A SOLUTIONGolden Flake brought in ADI Systemsto engineer a solution. The problemwas somewhat complicated by thefact that the plant is landlocked in itsposition, being in the Birminghaminner city. There was no room for siteexpansion, and little available room fora conventional activated-sludge facilitywith the footprint requirements forspray fields that would be required toprocess the plant’s wastewater flow.ADI Systems recommended the implementationof a membrane bioreactor(MBR) system to treat the raw wastewaterfollowing the vibrating screens.The ADI-MBR process, based on technologydeveloped by ADI Systems andKubota Corporation, is a form of activatedsludge technology that uses asubmerged membrane barrier to performthe liquids/solids separation and

eactor biomass retention functions, insteadof gravity clarification, whicheliminated problems associated withsludge settling and separation.The MBR process also fits on compactsites while providing consistent,high quality effluent that can be reusedin certain applications.Golden Flake representatives likedthe MBR approach as the treated wastewater(effluent) from the MBR systemcould then be discharged into theUpper Valley Creek, adjacent to theproperty, no longer requiring the needand expense of discharging wastewaterto the county sewer system.ADI Systems commissioned a 350-gallon MBR pilot plant onsite at GoldenFlake using a small stream of their prescreenedwastewater. The MBR pilotplant operated for three months todemonstrate and evaluate ADI-MBRtechnology for treating Golden Flake’swastewater.The MBR pilot study was a successand demonstrated that ADI-MBR technologywas easy to operate, could consistentlymeet the effluent limits, andproduce a direct discharge quality effluentwhile being situated on a sitewith a compact footprint.“The technology is really what soldus,” explained Mr. Jones. “We toureda couple MBR facilities in Georgia thatwere using the Kubota submergedmembranetechnology, and we werevery impressed by what we saw. Thequality of the effluent leaving theMBR for discharge into the streamwould meet the requirements of theAlabama Department of EnvironmentalManagement.”“The system also fits in to a verycompact and small footprint,” continuedMr. Jones. “This is what we neededfor our site.”MEMBRANE BIOREACTOR SYSTEMThe ADI-MBR system provides anear-absolute barrier to suspendedsolids and allows for operation athigher mixed liquor suspended solids(MLSS) concentrations (typically10,000 to 18,000 mg/L versus 2,000-5,000 mg/L as in conventional activatedsludge systems) resulting inlonger solids retention times, lesswww.filtnews.com • June 2011 • 25waste sludge production and a muchsmaller footprint.The ADI-MBR system at GoldenFlake consists of a pre-aeration tankand two membrane basins, eachequipped with double-decker submergedmembrane units (SMU).The MBR system is also equippedwith aeration blowers, a re-aerationchamber, pumps, instrumentation andcontrols. The total package includes acontrol building with a dewateringpress/conveyor system, automatic compositesamples, laboratory, office andPLC systems.During operation of the ADI-MBRsystem, treated effluent is passedthrough the membranes via a slightsuction, and then aerated to meet theDO limit prior to discharge to the adjacentstream. Waste activated sludgeis dewatered onsite with a screw pressand the sludge cake is removed fordisposal.“Membrane treatment technologiesare often employed when higher qual-

Membranes | WastewaterGolden Flake pre-aeration tank and MBR partially open.ity effluents are required,” said MikeMcDermaid, project manager for ADISystems. “Additionally, the ADI-MBRsystem is ideal when available plantfootprint is very limited, and when thewastewater characteristics make conventionalgravity settling technologiesdifficult or ineffective.”“The ADI-MBR process results in arobust, ultra-compact treatment system,occupying significantly less footprintcompared to a conventionalactivated sludge treatment system,”continued Mr. McDermaid. “We feltthis would be a very suitable applicationfor Golden Flake.”The ADI-MBR system at GoldenFlake provides a design hydraulic retentiontime of approximately 1 day,and is designed for a daily influent flowrate of up to 400,000 gpd. The systemtreats pre-screened wastewater withBOD and TSS concentrations that rangefrom 1,000 to 10,000 mg/L and 200 to12,000 mg/L, respectively.SYSTEM IMPLEMENTATIONThe new ADI-MBR system beganconstruction in February 2009, becameoperational in August 2009, and con-26 • June 2011 • www.filtnews.com

sistently produces effluent that is lowerthan effluent discharge limits set by theAlabama Department of EnvironmentalManagement:

Filter | TestingMeasuring the Performance of a Filter MediumBy Peter R Johnston, ConsultantWhen the process engineerfaces the question ofchoosing a filter medium,he also considers the device for holdingthe medium in the process stream. Thatis, he may employ a flat-sheet medium ora tubular cartridge-type filter.The flat-sheet design is straightforward.Consider the fluid-approach velocitywhile measuring filtration efficiency, aswell as measuring the volume of liquidpassing per area of the filter medium, beforethe medium either plugs with smallsolids, or a cake of permeable solidsforms. In the case of a tubular cartridge,the liquid does not evenly feed the surfacesof the medium. After all, both thefeed and the exit ports are at the same endof the cartridge, and some cartridges arevery long. Thus, a filter-performance testhas to be tied to the configuration of thefilter medium.Many cartridge-type filters are on themarket and an industry has been builtaround testing just cartridges. In thosetests, a specific test dust, with a specificparticle-size distribution, is mixed with aspecific liquid then fed the cartridge at aspecific flow rate.Then arises the question: How do testresults translate to the use of other fluids,particles, and flow rates?HISTORY OF “STANDARD” TESTSDuring the years 1975-1990 a group ofpeople met twice a year to review andwrite filtration tests, calling themselvesCommittee F-21 of the ASTM (AmericanSociety of Testing and Materials). Progresswas very slow because some attendeesdidn’t want any new test methods appliedto their filter media. Yet the committeemanaged to turn out about fifteen standardtest methods, all of which were advertisedfor comments before beingdeclared standard.Further, the National Fluid Power Association(NFPA) and the Society of AutomotiveEngineers (SAE), wrote testprocedures for measuring the performanceof cartridgefilters. Thosegroups employ asilica test dust inwhich their teachingof the particlesizedistributiondiffers from thatfound in ASTMRound-Robin studies[8].Around 1990,the American FiltrationSociety(AFS) asked membersto send incopies of test proceduresthey founduseful. In 1995,those procedureswere gathered in abook [1], whichsoon went out ofprint. (Used copiesare for sale on theInternet.) A 1990book [2] reviewedknowledge, whileadding guidelinesfor reporting test28 • June 2011 • www.filtnews.comresults, along with a plea to follow anEnglish-language style guide [3]. A 2004book [4] discussed using filters to sterilizeliquids.MEASURING FILTRATION EFFICIENCYWhat follows comes from two ASTMMethods [5,6].In comparing the particle-size distributionin the feed stream to that in the filtrate,via use of a particle counter, employthe term filtration ratio, R. That ratio, foreach particle diameter, d, is the numberconcentrations of particles in the feedstream to that in the filtrate.Avoid the beta ratio, the numbers of d-diameter-and-larger particles in the feedstream to that in the filtrate [7]. The betaratio is, obviously, a function of the particle-sizedistribution in the feed stream.Moreover, such a ratio provides an inflatedmeasure of filtration efficiency fordecreasing particle diameters.One paper, some years ago, even suggesteduse of the mass, or volume, ratiosof d-diameter-and-larger particles in thefeed stream to that in the filtrate. Thatprocedure provides an even greater inflationof filtration efficiency for decreasingparticle sizes, more so than the betaratio—while also being tied to the particle-sizedistribution in the feed stream.Many writers refer to particle size as alinear measurement without saying if theymean diameter or radius. Radius has beenemployed in studies of gas filtration.After gathering data of filtration ratiosR, vs. particle diameters d, the next questionis: How does one plot such data? Studentsof physical chemistry learn to plotdata so that straight lines appear, providinga clear relationship. It so happens thatplots, on log/log paper, of d vs. log R showstraight lines, illustrated in Figure 1.Then, add, across from log R, the corresponding,filtration efficiency, E, of individuald-diameter particles.For a given filter medium, K and n arefunctions of many variables, such as temperature,fluid flow-rate, the nature of thefluid, along with the natures of the particlesand the filter medium.Filter media are not sieves, as somewriters teach.During the course of a run, as solids fill

the surface voids of the filter medium, filtrationefficiency may increase.One feature of the Figure-1 kind ofplot is: On employing two layers of a filtermedium, in place of one layer, all logR values increase by a factor of 2.0. Forexample, when log R, for a certain d, increasesfrom 1.0 to 2.0, E increases from0.90 to 0.99.Investigators who maintain that a filtrationtest measures the size of the“largest” pores, by capturing a certain particlediameter with an efficiency of 0.99,or greater, would then wrongly say thatthe double-thick medium has smallerpores. Instead, it contains more internalsurface area, more pore walls.The NFPA, rather than saying a certainparticle diameter is captured (or stopped)with great efficiency, prefers to say it isseparated from the fluid stream, with aspecific removal efficiency. As mentionedabove, that group specifies use of the biasedbeta ratio.Figure 1 thus provides, via ASTMMethods [5, 6] a standard way of displayingresults. Recall, from the literature, thevery wide variety of different E scales, andd scales, and plotted curves readers areasked to digest.Of course, a less complicated measureof filtration efficiency lies in simply comparingthe turbidities of the two streams,or the mass concentrations of particles.MEASURING LIFE OR CAPACITYCase 1.When the liquid-driving pressure isconstant (constant head of liquid) makea plot, on log/log paper, of increasing volumefiltered, V, vs time, t. Compare thatplot to those in Figure 2, derived frommathematical rate constants [9].Notice, in Figure 2, all curves beginwith a straight line of slope 1.0, the symptomof laminar, viscose flow. If the slope isless, getting into inertia flow, the operatoris asking too much of the medium.It gets no better than Curve A, especiallywhen solids are to be recovered.Writers who plot V vs. t on linear/linearcoordinates cannot tell what kind ofblocking rates occurred or that desirablecake filtration was achieved, or that liquidflow was viscose.Case 2.When the liquid flow-rate is constant(using a positive displacement pump),and when the initial flow is viscose, makea plot, on log/log paper, of the increasingwww.filtnews.com • June 2011 • 29driving pressure, P, vs. time, t, and comparethat curve to the curves in Figure 3.When Curve D does appear, in eitherFigure 2 or 3, the addition of a filter aidto the feed stream, while also pre-coatingthe filter medium with filter aid, often enablesan almost Curve A.Sometimes a filter medium withsmaller pores may change a Curve D intoCurve C or B, or even A.Make sure “driving pressure” is thepressure drop across the faces of the filtermedium, and does not include addedpressure drops across the device holdingthe medium.

Filter | TestingIn a test of cartridges filters [10] wherethe feed and exit ports are at the same endof the cartridge, a Figure 3 kind of plotshowed curves similar to Curves B, andC. Again, plots on linear/linear coordinatesfail to tell what plugging rates occur.Case 3.When a centrifugal pump is employedto feed the filter medium, and the system“rides the pump curve,” plot data as inFigure 4, to see which theoretical curvematches the test results. These curves derivefrom data in Figures 2 and 3.MICRON RATINGSome writers have adopted a practiceof assigning a micron rating to a filtermedium, meaning that micron-diameterparticle the medium stops with an efficiency,E, of 0.98 (R = 50) or higher, in acertain (and sometimes arbitrary) filtrationtest.But, of course, as mentioned above, therating has to be tied to many variables, i.e.,the nature of the medium, the thickness,the specific fluid, the fluid velocity, temperature,and the specific test particles.A more realist rating, for a flat-sheetmedium, involves the structure, that is,the material(s) of construction, thickness,permeability in liquid viscose flow, andporosity, from which deduce the viscoseliquid-flow-averaged pore diameter. Thesesubjects belong in a separate discussionthat also involves the meanings of poresizedistributions, and the size of the“largest pores.”A WAR STORYMany years ago the present writer accompanieda salesman calling on a potentialcustomer who was using Brand Xfilter cartridges. We learned that if wecould demonstrate that our cartridge is asefficient as Brand X, he would considerus. He wanted to see test results of filteringhot water contaminated with particlesof black iron oxide.Accordingly, we tested in our lab bothBrand X and our cartridge, and saw identicalresults. Returning to the potentialcustomer, we showed him our plots of filtrationefficiency vs. particle diameter. Heresponded that Brand X is more efficientthan we had found.Later we learned that the Brand Xpeople had showed him results wherethe liquid was not hot water. It was aFNlow-viscosity oil.For more information contact:Peter R Johnston, ConsultantTel: 1-919-942-9092Email: ddandp3@aol.comReferences[1] Johnston, P.R, 1995, A Survey of Test Methods in Fluid Filtration.Gulf Publishing Co.[2] Johnston, P.R. 1990, Fundamentals of Fluid Filtration, a TechnicalPrimer, Tall Oaks Publishing Co, 2nd edition.[3] Strunk, William Jr, and White E.B, The Elements of Style,MacMilliam[4] Johnston, P.R., 2004, Fluid Sterilization by Filtration, 3rd edition,Interpharm./CRC Press[5] ASTM F797-88, Standard Practice for Determining the Performanceof a Liquid Filter Medium Employing a Single-Pass, Constant-Rate, Liquid Test.[6] ASTM F796-88, ...Constant Pressure...[7] Dickenson, Christopher, 1992, Filters and Filtration Handbook,Elsevier Publishers[8] Johnston, Peter R., and Roy Swanson. 1982. “A Correlation Betweenthe Results of Different Instruments used to Determine theParticle-Size Distribution in AC Fine Test Dust,” Powder Technology,32: 119-124.[9] Grace, H.P. 1956, “Structure and Performance of Filter Media,”AIChE Journal, 2: 307-336[10] Johnston, Peter R., James E. Schmitz, 1974, “A New and RecommendedWay to View the Performance of Cartridge Filters,” Filtration& Separation, 11, Dec.30 • June 2011 • www.filtnews.com

Show Report | Filtech 2011Filtech 11 – Largest Event Since BeginningBy Adrian Wilson, European CorrespondentThis year’s Filtech show, whichtook place in Wiesbaden, Germany,March 22-24, was biggerand better than ever, with exhibitors upby 46% and visitors up by 38%.As the founder of Filtech, Mike Taylorexplained that this highly successful showstarted in the 1960s at the Olympia inLondon, later moving to Holland, beforesettling in Germany.“This reflects how the country hascome to dominate in Europe in the automotivefield and many other industrialareas,” he said. “Wiesbaden is a short distancefrom Frankfurt and its Rhein-Maincenter is an excellent choice for an exhibitionof this size.”At the same time, 56% of visitorstravelled to the show this year from outsideGermany, reflecting the globalstructure of the filtration industry, and avery comprehensive conference featuredover 180 papers.CENTER STAGE FOR H&VTaking center stage in Hall 1 at Filtech11 was Hollingsworth and Vose, one ofthe key players in nonwoven-based filtermedia, with manufacturing sites in theAmericas, Europe and Asia.The company’s NanoWave range ofnanofibrous membranes have a range ofuses, and at Filtech, the company outlinedhow, for example, they are achievingmassive savings for a manufacturer ofbusiness and civilian jets.At its U.S. dry-paint spray booth facilities,this company collects oversprayFounder of the Filtech show, Mike Taylor,with members of his team, Ariana Chittka(left) and Yvonne Klose, in Wiesbaden.www.filtnews.com • June 2011 • 31

Show Report | Filtech 2011The Eurocarb teamIrema’s Anja-Michen Mueller at thecompany’s Filtech booth.Karl-Keinz Knotz and RogerTischauser of Lanz-AnklerReto Vogt of Textest shows their newMobilair FX 3320 portable airpermeability tester.Fabio Bruschi of TenaxThomas Maahsen and MichaelCasp of Jentschmann AG showstheir ultrasonic cutting system.paint in bag filters that periodically needto be replaced to ensure a consistent flowacross the paint bay. Obligated by law tocomply with proper procedures for thedisposal of hazardous waste, the companywas making eight filter set changes annuallyat a cost of $11,000 each.Annual savings as a result of replacementwith H&V’s NanoWave-based bagshave been put at $45,000, as a result ofthe media’s dust-holding capacity, whichis said to be double that of both syntheticand glass fiber alternatives.SURFACE AREANanofiber layers are the latest generalprogression for nonwoven-based filtermedia, allowing greatly expanded surfacearea which allows for maximum efficiencywith low resistance, while furtherincreasing particle-loading area.As a consequence, most leading companiessupplying nonwoven-based mediaare employing them, but Germany’s Iremahas gone a stage further, in introducing apatented single-step process for producingmeltblown nonwoven webs with fullyintegrated nanofibers.The company’s 100% polypropyleneminipleat filter has recently been testedand certified to a number of standards,which prove its performance to be on parwith glass fiber.“The demand for our patented new filtermedia, manufactured on the latestgeneration of our proprietary lines, isgrowing continuously, particularly in theventilation and air conditioning markets,”said the company’s Anja-Michen Muellerat Filtech.Such new developments are only likelyto intensify in the coming years – the filtermedia market now has an overall annualvalue of over $20 billion.TECHNOWEB PROWith production facilities currently inAsia, South Korea’s Finetex says it has expansionplans for both North Americaand Europe. The company’s patentedTechnoweb Pro nanofiber technologyproduces webs, which are both glass andfluoro free.“Our nanofibers are mechanicallystructured, as compared to other materialswhich rely heavily on an electrostaticcharge, pre-treated media or a combinationof very expensive nonwoven materialswhich can lose efficiency over arelatively short period or time,” said sales32 • June 2011 • www.filtnews.commanager David Seung. “Due to the literallymillions of channels in Technoweb,we can provide greater life expectancy forevery filter made, with less pressure dropand inexpensive nonwoven substrates, foreither surface or depth filtration.Typical applications are in HVAC,HEPA and ULP clean-room grades andtransportation, and the company is currentlydeveloping products for both themedical industry and battery separators.Of particular significance as far asmedical applications are concerned, thelayered structure of Technoweb has millionsof pores, just like human tissue. Itexceeds 99.99% filtration at 01. micronswith good absorption and diffusion. Potentialapplications here are anti-bacterialmasks, surgical drapes, caps and gowns,sterile barrier systems and even cell culturefiltration systems.Techoweb separators can also be usedin lithium-ion batteries for consumerelectronic devices, in addition to reservepower and grid management systems andelectric vehicles.Techoweb advantages here includeoutstanding electrolyte affinity and impregnation,lower electrode and electrolyteinterface resistance and high ion

Birte Mahn and Elom Westi of Pintashowcased reticulated foam andnonwoven media with active carbon.conductivity. In addition, the quality ofthe membrane can be easily controlledand the streamlined production processresults in lower cost.NANOFICSA group of nano-scaled functionalcoatings called Nanofics has been developedby Europlasma, based in Oudenaarde,Belgium. The coatings are appliedby low pressure plasma polymerisationand are typically thinner than 100nm.Europlasma’s Nanofics technologyguarantees a uniform coverage of complex,three-dimensional structures andapplications include:• Super hydrophobic nanocoatings –to protect electronic devices such as hearingaids or smartphones against liquiddamage, to protect PCBs against corrosion,to make ultra-light liquid aircraftfoams water repellent, for engine air intakeconducts and for improving the performanceof diesel engine filter media.• Oleophobic nanocoating to improvethe efficiency of electret filter media, tomake super oleophobic filter membranesto level 8, to prevent cell growth on medicalimplants and to improve personalprotective equipment.• Super hydrophilic coatings to improvethe wettability of culture growthproducts, blood filter media, battery separators,etc.• Barrier coating to prevent the oxidationof metal surfaces and for food packagingmaterials.David Seung and Donald Cho ofFinetexSpecifically for gas filter media,Nanofics can be employed for:• The oleophobic nanocoating of electrets• Respirator masks• HVAC filter media• Hydrophobic nanocoating ofair conducts• Super oleophobic nanocoating of filtrationmembranes• Hydrophobic nanocoating of dieselengine filtersFor liquid filter media, Nanofics canapply hydrophilisation to porous plasticsand ceramics and hydrophilic coatings toblood filter media and battery separators.ACTIVATED CARBONEurocarb is the European center of operationsfor Sri Lanka-headquartered Haycarb,the world’s leading manufacturer ofcoconut shell activated carbon with anannual capacity in excess of 22,500 tons.Haycarb recently received attention forthe completion of its Recogen project –the world’s first industrial electricity generatingcharcoaling plant. Recogen is recognizedas a carbon credit generatingfacility by the Kyoto protocol.Eurocarb provides effective solutionsfor the removal of gas and vapor contaminantsfrom air, with its high purity materials– whether derived from coconutshell, coal or wood carbons – providingan optimum balance of surface area, densityand hardness.The highly micro-porous structure ofcoconut shell carbons in particular, is eminentlysuited to the removal of smallmolecules such as volatile organic compounds.Eurocarb carbons are also useddaily in critical water filtration applications,where material homogeneity ensuresconsistent water flow and silverimpregnation adds protection and longlife to filter units.“In many cases we have supportedcustomers in determining an activatedcarbon particle size specification that balancesadsorption capacity against pressuredrop within desired parameters,” saidMarket Development Manager KC Perera.www.filtnews.com • June 2011 • 33METAL REPLACEMENTItalian-headquartered Tenax introduceda new family of plastic nets madefrom PBT (polybutylene terephthalate).“They can very successfully replacemetallic parts in filters cartridges,” explainedFabio Bruschi, market managerfor the company’s Industrial and PackagingDivision,“ as spacers for filter media,pleating supports, rigid tubes for innercores or external cages. They can be usedto assemble completely metal free filtercartridges which can be incinerated atend of life and they possess a good degreeof shape memory and can be veryeasily pleated.”In respect of mechanical properties,the PBT meshes have a high resistance todeformation at high temperatures and/orin contact with organic solvents, whilemaintaining a high toughness even whenused at low temperatures.Key characteristics include:• Yield strength of 52mpa• Maximum operating temperatureof 180-200ºC• Minimum operating temperatureof –40ºC• Melting point of 220-230ºC• Good resistance to organic solvents• Good creep resistance• Flame retardancyREGULATIONSWilhelm Höflinger of the ViennaUniversity of Technology explainedhow increasingly stringent Europeanregulations are currently driving thedust filtration market alone.“Fine dust, especially particlesbelow one micron, can cause seriousheart and respiratory disease andmore efficient pollution standardshave recently been introduced to improvethe ambient air quality in Europe,”he said. “This is the drivingforce for speedily improving existingdust separators in respect of their fineparticle separation ability.”Add to this the need for cleanerwater, a demand for finer degrees ofseparation in industry, the drive forbetter hot exhaust gas filtration andfor higher energy efficiencies in allseparation operations, and it becomesclear why Europe’s filtration industryis currently so buoyant, and why Filtechremains a vital platform for theexchange of ideas.FN

Mini Mart Ads34 • June 2011 • www.filtnews.com

www.filtnews.com • June 2011 • 35Mini Mart Ads

Advertiser IndexPage WebsiteA2Z Filtration Specialities 16 www.a2zfiltration.comAFS Conference Inside Front Cover www.afssociety.orgAir Filter, Inc. 9 www.airfilterusa.comAshby Cross Co. 18 www.ashbycross.comFiltration News Buyers’ Guide Inside Back Cover www.filtnews.comClack Corporation 29 www.clackcorp.comContract Pleating Services 30 www.solentech.comDexmet Corporation 9 www.dexmetfilter.comEd Gregor 24 ecg@edgregor.comFerguson Perforating 31 www.fergusonperf.comFTG 11 www.ftginc.comINDA 7 www.inda.orgIndustrial Netting 31 www.industrialnetting.comJCEM-USA 23 www.jcem.chLawrence Industries, Inc 36 lawrenceindustries@juno.comMaag Pump Systems 10 www.maag.comMagnetool Inc. 26 www.magnetoolinc.comMetalex 28 www.metlx.comMetcom Inc. 26 www.metcomusa.comOrange Research, Inc. 17 www.orangeresearch.comOrival Inc. 19 www.orival.comPerCor Mfg. 8 www.percormfg.comPerforated Tubes 15 www.perftubes.comRosedale Products Back Cover www.rosedaleproducts.comSealant Equipment 25 www.sealantequipment.comSolent Technology Inc. 6 www.solentech.comSonobond Ultrasonic 27 www.sonobondultrasonics.comSpati Industries, Inc. 21 www.spatiindustries.comSpin Tek Filtration 1 www.spintek.comXinxiang Tiancheng Aviation 5 www.tchkjh.comAd Representatives:AUSTRIA, GERMANY,SWITZERLANDBruno FischWerner MeierIFF Media AGEmmersbergstrasse 1CH-8200 Schaffhausen,SwitzerlandTel: 41 52 633 08 88Fax: 41 52 633 08 99Email: b.fisch@iff-media.chEmail: w.meier@iff-media.chBENELUX, FRANCESabine DusseyINTERNATIONAL JOURNALSDuppelstr. 7D-42781 Haan, GermanyTel: 49 2129 348390Fax: 49 2129 3483910Email: Sabine.Dussey@dussey.deCHINAMr. Zhang XiaohuaMobile: 0086 13522898423Mr. Han JiweiMobil: 0086 13810778772Email: ifj_china@yahoo.com.cnBeijing, ChinaINDIAYogesh JogBRIDGE MEDIAD-302, Shiromani ComplexNr Nehrunagar – Satellite RoadOpp Ocean Park, Satellite,Ahmedabad – 380015.Tel: 91 79 26752628Telefax: 91 79 26762628Mobile: 98242 31895Email: media.bridge@gmail.comITALYFerruccio SilveraSilvera PubblicitáViale Monza 24, I-20127 Milano,ItalyTel: 39 02 284 6716Fax: 39 02 289 3849Email: ferruccio@silvera.itJAPANKenji Kanai36 • June 2011 • www.filtnews.com3-9-25, Wakamatsudai, SakaiOsaka 590-0116, JapanTel: 81 6 6343 4513Fax: 81 722 93 5361Email: fwpb9629@mb.infoweb.ne.jpKOREAYoung-Seoh ChinnJES MEDIA Inc.2nd Fl.,ANA Building257-1, Myungil-DongKangdong-Gu,Seoul 134-070, KoreaTel: 82 2 481 3411/3Fax: 82 2 481 3414Email: Jesmedia@unitel.co.krTAIWANBuildwell Intl. Enterprise Co. Ltd.No. 120, Huludun 2nd St., FongyuanCityTaichung County 42086, TaiwanTel: 886 4 2512 3015Fax: 886 4 2512 2372Email: buildwel@ms23.hinet.netUNITED KINGDOMJudy HollandTextile Media Services Ltd.2A Bridge Street, SilsdenKeighley, BD20 9NB, UKTel: 44 1535 656489Fax: 44 8700 940868Email: jholland@textilemedia.comUSA, CANADABob MooreRAMCOP.O. Box 4032Cave Creek, AZ 85327Tel: 1 480 595 0494Fax: 1 480 595 1749Email: ramco@qwest.netALL OTHER COUNTRIESKen NorbergEditor, International Fiber JournalPO Box 265Winchester TN 37398 USATel: 1 202 681 2022Email: ken@ifj.com