44 www.paintsquare.comJ P C L A p r i l 2 0 0 8

igh-performance protective coatings often fail in the severe environ-ment of the headspace in domestic wastewater collection and treat-ment systems. Coating failures are attributed to many factors, includ-ing extensive permeability to hydrogen sulfide gas (H2S) and othercorrosive gases present. Although the chemical and physical proper-ties of coating systems can be determined in the laboratory, this isnot the case for the effects of environmental conditions, such asexposure to severe environments within wastewater headspaces.Unfortunately, specifiers for the wastewater sector are often faced

with selecting from an array of protective coatings that have not beensubjected to testing specifically for the wastewater environment, inlarge part because of inadequate laboratory tests for coating perfor-mance in all the conditions in the facility. This article discusses theadvances in a novel cabinet testing protocol designed to simulate theeffects of the severe conditions in a wastewater headspace. This testprotocol produces data that can be interpreted in 28 days.

Editor’s Note: This article is based on a presentation givenat PACE 2008 in Los Angeles, CA, in January 2008. TheConference Proceedings contains an earlier version of thearticle. The present article is the final version of the arti-cle. PACE is the joint conference of SSPC: The Society forProtective Coatings and the Painting and DecoratingContractors of America (PDCA).

*Currently with RAE Engineering and Inspection Ltd.

H

by Vaughn O’Dea and Rémi Brand, Tnemec Company, Inc.;and Linda G.S. Gray, KTA-Tator (Canada) Inc.*

Accelerated Test EvaluatesResistance to Severe Exposures

AssessingCoatings

& Liningsfor Wastewater:

Photoby

AnnAkesson

By Vaughn O'Deaand Remi Briand,Tnemec Co.;and Linda Gray,*KTA-Tator (Canada) Inc.

permeability of coatings and linings tothe corrosive gases and liquids in thewastewater vapor phase has been shownto substantially increase coating perfor-mance.6 Although perhaps not linear, theatmospheric H2S concentrations appearto be proportional to the rate of sewercorrosion.7 It can also be assumed thatincreased H2S concentrations contributeto greater permeation of polymeric coat-ings and linings. These sewer gases, par-ticularly H2S, compromise the barrierqualities of a protective coating. In thepresence of moisture, H2S can be biologi-cally oxidized to form H2SO4, whichrapidly attacks the underlying substrate.Several notable wastewater testing

programs, including the “Evaluation ofProtective Coatings for Concrete,” per-formed by the Sanitation Districts of LosAngeles County and the “ChemicalResistance Pickle-Jar Test,” developed bythe Standard Specifications for PublicWorks Construction (Greenbook), havebeen performed throughout the years to

BackgroundThe U.S. municipal wastewater infra-structure is deteriorating rapidly due inpart to the effects of biogenic sulfide cor-rosion. Biogenic sulfide corrosion is abacterially-mediated process in whichhydrogen sulfide (H2S) is formed andsubsequently undergoes biological oxida-tion to form sulfuric acid (H2SO4).Sulfuric acid attacks concrete and steelwithin wastewater headspaces.1

Domestic wastewater varies widely incomposition. The main component iswater (~95%) added during flushing tocarry the waste to the drain. Other com-ponents of wastewater include pathogen-ic and non-pathogenic bacteria, organicparticles, inorganic particles, animals,macro-solids, and emulsions. The typicalpH of domestic wastewater is 6.0 to 9.0.Although septic in nature, the untreatedwastewater itself is not particularlydetrimental to the concrete or steel infra-structure. Rather, H2S gas in the head-space above the waterline in enclosed

sewer pipes and structures is principallyresponsible for subjecting the concreteand steel appurtenances in the headspaceto highly corrosive exposures.Hydrogen sulfide gas has always been

present in collection systems up to 10parts per million (ppm).2,3 However, inthe past few decades, as a result ofchanges related to water conservation,industrial pretreatment, and designphilosophies, the conditions in waste-water collection and treatment havebecome more aggressive. The changeshave produced H2S concentrationsexceeding 100 ppm (and occasionallymeasured upwards of 1,000 ppm). Thechanging conditions have contributed torapid deterioration of the wastewaterinfrastructure.4

Traditional coatings, as well as high-build protective coating and lining tech-nologies, are routinely failing undersevere wastewater conditions, leading toa need for costly renovation of sewer net-works and treatment structures.3,5 Low

J P C L A p r i l 2 0 0 8 45www.paintsquare.com

Vaughn O’Deais Director ofSales, Water &Wastewater, forTnemecCompany, Inc.,where he isresponsible forstrategic sales,marketing, andtechnical initia-

tives. He is an SSPC Protective CoatingsSpecialist, a NACE-certified CoatingInspector Level 3, and a NACE-certifiedCorrosion Technician. He has publishedwidely and is active in the technical com-mittees of NACE and SSPC. He is amember of AWWA, WEF, ACI, ICRI, andAPWA.

As VicePresident ofResearch &Development forTnemec, RemiBriand isresponsible formanaging R&Dprojects, perfor-mance testingand quality con-

trol of the company's products. He hasover 20 years of experience in theresearch and development and the man-ufacturing of high-performance coatings.A member of SSPC and FSCT, Remi

has co-authored a paper for the 2003WEF Technical Exposition & Conferenceand has written for several technical pub-lications related to the coatings industry.

Linda Gray is aSenior MaterialsSpecialist withRAE Engineeringand InspectionLtd. and hasover 20 years ofexperience incorrosion andcorrosion con-trol. She man-

ages a protective coatings testing labora-tory. Her technical specialties includedesign of custom tests, failure analysis,application of EIS in coating testing, andother consulting services for coatings.She is an SSPC Protective CoatingsSpecialist and a NACE Coating InspectorLevel 2-Certified.

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46 www.paintsquare.comJ P C L A p r i l 2 0 0 8

test the viability of high-performanceprotective coatings in wastewater expo-sures.8,9 These testing programs providea good qualifier for the suitability of acoating for wastewater structures.However, simulated wastewater envi-ronments have been studied mainly byusing sulfuric acid (and other individualreagents) directly as the corrosive agentand may not reflect corrosive conditionsfound in wastewater headspaces, whichinclude H2S gas. In other words, the test-ing basis of these programs is strictlychemical immersion. Likewise, someinvestigations have shown that even ifconcrete shows a certain resistance toH2SO4, it does not always indicate resis-tance against biogenic sulfide corro-sion.10 In addition, these existing pro-grams have no readily available meansto characterize a coating and the qualityof permeation resistance.

Objective of StudyIn 2000, through a collaborative effort,researchers pioneered a laboratory test-ing protocol to rapidly evaluate the per-formance of coating systems for theirresistance to permeation by H2S andH2SO4. This testing program, namedSevere Wastewater Analysis Test(S.W.A.T.), was based on a testing cham-ber (Fig. 1) that permits the simulationand acceleration of the conditions char-

acteristic of severe environments inwastewater headspaces. The evaluationmethod allows a comparative evaluationof the performance of commerciallyavailable products intended for severewastewater exposures. It differs consid-erably from other laboratory testingmethods by evaluating a material’s per-meation resistance to elevated concen-trations of H2S gas.For the ultimate in coating evaluation

for wastewater, field exposure is still thegold standard. However, some of today’sadvanced high-build protective liningswith low permeation characteristicsoften require over 10 years of field test-ing to generate usable data. Additionally,field conditions may be mild (relative toH2S), inconsistent, or changeable duringthe test period. As a result, performanceclaims have often been based upon anec-dotal evidence of field histories. The roleof the chamber is to provide a standard-ized, accelerated method for the evalua-tion of a coating’s perfor-mance in wastewater head-space conditions.In 2003, Briand and

Nixon presented data oncommon high-performanceprotective coatings subjectedto the Severe WastewaterAnalysis Testing program.11

They concluded that perme-

ation resistance is the key factor in thesuccessful performance of coatingsplaced in wastewater headspaces. Theauthors also proposed a laboratory test-ing protocol as a measure of a coating’spermeation resistance to these corrosiveenvironments. This article updates theadvances in the testing procedure forcoatings in severe wastewater exposure.

Accelerated TestingParameters

It is generally accepted that cabinet testsprovide comparative results and notabsolute results.12 Hence, the role of thewastewater chamber is to provide anaccelerated evaluation of a coating’s rela-tive performance under simulated waste-water headspace conditions. The corro-sion protection of steel and concrete by aprotective coating or lining may bealtered by exposure to elevated gasesand by the composition of the corrosivemedia. Exposing coated steel and con-

Fig. 2: Severe Wastewater Analysis Testing specimens. (not to scale)(left) coated steel panel; (middle) coated cylindricalconcrete specimen; (right) molded free film sample

Fig. 1: The Severe Wastewater Analysis Testing chamberPhotos and figures courtesy of the authors

Fig. 3: Logarithmic key for interpretation of the impedance datarelative to barrier protection afforded by organic coatings.

Poor Good ExcellentBarrier Protection

Begins

EIS Coating Impedance, Log Z (Z0.1 Hz Ω cm2)

Increasing Corrosion Protection

Corrosion Protection of Organic Coatings

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crete panels to the wastewater chambercan help determine the suitability ofthese coatings or linings.

Severe WastewaterAnalysis Test (S.W.A.T.)

The severe wastewater chamber is noth-ing more than a static testing vessel usedto expose coated test specimens to a cor-rosive environment at elevated tempera-tures, so that the effect of such an envi-ronment can be evaluated. The test simu-lates severe wastewater headspace condi-tions by cyclic wetting of coated sampleswith a corrosive solution containing sul-furic acid and exposing the wetted sam-ples to air containing high concentrationsof hydrogen sulfide gas. The S.W.A.T. pro-cedure is unique in that it simulates theheadspace environment of enclosedwastewater structures, where perme-ation by hydrogen sulfide gas (and othergases present) alters the properties ofhigh-performance lining systems. It is ulti-mately this aggressive mixture of liquiddroplets in the presence of H2S thatrapidly permeates a protective film.Chemical selection for the S.W.A.T. is

based on the easily detectible corrosivespecies in headspaces: H2S and H2SO4.(Other gases are also present in theseenvironments and can be incorporatedinto the wastewater chamber.)Prior work by Briand and Nixon estab-

lished gas concentrations and testingduration by evaluating the permeation

performance of various polymers atvarying levels of H2S gas.1 It was con-cluded that the permeation performanceof various protective coatings tested inthe S.W.A.T. for a period of 28 days par-allelled their performance in the field.Additionally, preliminary studies using

bare (uncoated) concrete specimensexposed to the S.W.A.T. chamber indicatea concrete mass loss of approximately0.877 in. (2.2 cm) in a year. This massloss parallels many documented cases ofconcrete paste loss of nearly 1 in. peryear from walls and soffits (ceilings)under severe field conditions.13

The average temperature of waste-water in the U.S. is between 10 and 21 C(50 and 70 F). The S.W.A.T. operates at atemperature of 65 C (150 F) to induce an

accelerated reaction rate that is approxi-mately 3 times the actual rate for waste-water headspace conditionsThe corrosion of sewers and other

facilities and odorous gases in sewers areprincipally related to the generation ofhydrogen sulfide. It has also been foundthat permeation by hydrogen sulfide gas(with other sewer reactants) alters filmproperties of protective coatings andcontributes to their blistering and crack-ing.11 The gas content of 500 ppm H2Swas selected for S.W.A.T. based uponearlier studies showing parallelled coat-ing permeation results when testing withgreater concentrations (10,000 ppmH2S).11 Therefore, the 500 ppm is usedto expose samples to realistic levels ofhydrogen sulfide that may be encoun-

J P C L A p r i l 2 0 0 8 49www.paintsquare.com

Fig. 4 (above): Summary of EIS impedance data for 3 different coatings technologies:Control, and Post-S.W.A.T. Product A (left): Coal-Tar Epoxy—no retained impedanceproperties; Product B (middle): Novolac Epoxy—no retained impedance properties;Product C (right): High-Build Amine Epoxy—98% retained impedance properties.

Fig. 5 (right): Example of optical microscopy measurements of coatingapplied to concrete cylinder specimen.

Permeability

ControlPost-S.W.A.T.

Total DFT: 74 milsPermeation: 21 mils

Permeation: 28%

Tensile Properties

ControlPost-S.W.A.T.

Tens

ileSt

reng

th,p

si(A

STM

D638

)

Elon

gatio

n,%

(AST

MD6

38)

Product D Product E

Fig. 6: Example results for testing the tensile properties. Product D, an elastomeric polyurea, lost 55%tensile strength properties (left) and 31% elongation properties (right) when exposed to S.W.A.T. cabinet.

(55)%(31)%

tered under field conditions. Air con-taining 500 ppm H2S is bubbledthrough the aqueous solution to super-saturate the solution.Other gases commonly found in

untreated wastewater include carbondioxide, methane, and ammonia.14,15,16

Like H2S, these gases are derived fromthe decomposition of the organic matterpresent in wastewater. Since the concen-trations of the latter three gases are not

widely understood relative to H2S with-in wastewater collection systems, theyhave been withheld from testing untilfurther research is conducted. (Data col-lection is currently underway by theauthors for future incorporation into theS.W.A.T. protocol.)As H2S levels have increased within

severe wastewater environments, so hasthe production of H2SO4 byThiobacillus sulfur oxidizing bacteria(SOB) that colonize in the headspaces.4

The theoretical concentration of H2SO4generated by SOB is proposed to be 5 to7% H2SO4.4,14 The S.W.A.T. incorpo-rates 10% H2SO4 into the aqueousphase of testing; this concentration ofacid is slightly above the maximumobserved produced by the SOB. Incoastal areas, salt (sodium chloride orNaCl) in water vapor can be very dam-aging to steel surfaces.17 The concentra-tion of 0.4% (or 4,000 ppm) sodiumchloride was incorporated into S.W.A.T.

to enhance the solute conductivity andto duplicate saltwater intrusion found inmany of these coastal collectionsystems.18 The aqueous solution is alsosaturated with H2S by bubbling the air-H2S gas mixture through the solution.

Testing ProceduresThe suitability of a particular lining sys-tem in severe wastewater environmentsis based upon the retained properties ofthe coating with regard to permeability,

physical testing, and visual inspections.This evaluation is accomplished by test-ing candidate lining systems on steel andconcrete substrates, as well as testingmechanical properties of molded samples(Fig. 2 on p. 46).

PermeabilityPolymeric coatings act as a barrier sepa-rating the substrate from the corrosiveservice environment.A key attribute in theperformance of theprotective coating is,therefore, a low per-meability to salts,water, gases, acids,and other corrosivespecies.Electrochemical

impedance spec-troscopy (EIS) analy-sis is a technique wellsuited for evaluating a

50 www.paintsquare.comJ P C L A p r i l 2 0 0 8

coating’s permeability (barrier) propertiesbased on the electrical resistance provid-ed by the coating. This is referred to asimpedance. The impedance of the coatingis related to the nature of the polymer, itsdensity, film thickness, and fillers. EIS hasbeen widely used in the laboratory andfield within the protective coatings indus-try for determining a coating’s perfor-mance and obtaining quantitative infor-mation on coating deterioration.19,20,21

When used with cabinet tests, EIS analy-sis acts as a quantitative detector of coat-ing quality.20

When interpreting permeation resis-tance using EIS, the higher and more sta-ble the retained impedance following ex-posure, the better the long-termpermeability resistance and, therefore, thebetter the long-term coating performance.The logarithmic impedance scale present-ed in Fig. 3 (p. 46) is derived from a largebody of literature on laboratory and fieldwork.22

EIS control readings are taken beforethe coating is exposed to the S.W.A.T. andthen compared to post-S.W.A.T. imped-ance to determine if the polymer was per-meated or attacked during the test. Anypolymer degradation is easily detected bya decrease in the measured impedance.Experimentally, impedance of a coating

is determined as a function of the fre-quency of an applied AC voltage. Thedata consist of a Bode plot of Log Z ver-sus Log f, where Z is impedance inohms cm2 and f is frequency in Hertz

Fig. 7: Example results for testing the flexural properties of three high-build epoxy mortars.Product E (left) lost 9% of initial flexural strength; Product F (middle) lost 20% of initial flexural

strength; Product G (right) lost 20% of initial flexural strength.

Fig. 8: Example of two polyurethane hybrids (fast-sets)tested for adhesion using parallel knife test.

Flexible Properties

ASTM

C580

psi

ControlPost-S.W.A.T.

•

J P C L A p r i l 2 0 0 8 51www.paintsquare.com

(0.05 Hz to 100 kHz). From the Bodeplot, Log Z0.1 Hz is determined by inter-polation. The Log Z value at 0.1 Hz istabulated and used as the basis of com-parison between coatings and for moni-toring the change of a coating as a func-tion of exposure time to the test environ-ment. Selection of Log Z0.1 Hz is some-what arbitrary but represents a compro-mise between speed of analysis and theselection of a frequency at which differ-ences in coating performance can be reli-ably determined.22

An example of EIS analysis of threeproducts commonly used in wastewateris compared in Fig. 4 on p. 49. (The redline at Log Z 6.0 is an indication of where“barrier protection begins”.) Product A—a coal-tar epoxy—exhibited excellent ini-tial impedance values. However, theproduct blistered and cracked duringS.W.A.T. exposure and showed noretained impedance. Similarly, ProductB—a high-build novolac epoxy—demon-strated excellent initial EIS impedancevalues. However, this product alsoshowed no retained impedance followingthe S.W.A.T. exposure. Product C—afiber-reinforced high-build amineepoxy—showed excellent initial EISimpedance. Following the 28-dayS.W.A.T. exposure, the product retained98% impedance. This is an indication ofthe product’s low permeation to the cor-rosive wastewater species.In addition to EIS analysis, permeation

of a coating following wastewater cabinetexposure can also be assessed by micro-scopically observing the cross-section ofthe coating film. Permeation by thesevere wastewater reagents typicallymanifests as discoloration when viewedwith 100X microscope with digital imag-ing.Figure 5 (p. 49) shows a high-build

amine epoxy applied at an average of 74mils (1,850 microns) dry film thickness(DFT) to a cylindrical concrete specimen.The concrete specimen is cut to expose across-section of the coating. The cross-section of the film is then measured with

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following post-S.W.A.Texposures.

The commonly usedlaboratory methods tomeasure the tensile prop-erties of coatings and lin-ings are ASTM C307,Standard Test Method forTensile Strength ofChemical-ResistantMortar, Grouts, andMonolithic Surfacings;

ASTM D638, Test Method for TensileProperties of Plastics; and ASTMD2370, Standard Test Method forTensile Properties of Organic Coatings.Tensile control properties are estab-

lished for each candidate lining system

using one of the aforementioned ASTMmethods. For comparison, the specimensare then subjected to the S.W.A.T., andtensile strength is measured again.Figure 6 (p. 49) is an example of suchtensile testing, where Product D—anelastomeric polyurea—exhibited excel-lent initial tensile and elongation proper-ties. However, when subjected to thewastewater cabinet, the tensile proper-ties of Product D were significantlyreduced by 55% and elongation wasreduced by 31%. A deduction can bemade that this polymer technology is sig-nificantly embrittled by the severewastewater exposure.A polymer sample has flexural

strength if it is strong when one tries tobend it.22

Evaluating the flexural properties isimportant to determine the effects ofsevere wastewater exposures on thepolymer. Like tensile properties, a signifi-cant decrease in retained flexural prop-erties may indicate that the polymer islosing plasticity or becoming embrittledand may ultimately crack under long-term field conditions.Figure 7 (p. 50) compares the initial

and post-S.W.A.T. flexural properties ofthree high-build amine epoxy trowel-applied mortars marketed for severewastewater applications. A deductioncan be made, based upon this compari-son, that it is not the greatest initial flex-

ural strength (psi) that isimportant, but rather theretained flexural proper-ties.Product E lost only

9% of its flexural proper-ties compared toProducts F and G, whichwere reduced by 20%.This sharp decline offlexural strength in thelatter two products indi-cates greater attack onthe mechanical proper-ties of the polymers andperhaps a greater

propensity to crack under long-termwastewater field conditions.Other ASTM laboratory testing meth-

ods are available to measure the mechan-ical or physical properties of coatingsand may be incorporated into theS.W.A.T. to measure the effects of thewastewater exposure.One such testing method is ASTM

D4541 Standard Test Method for Pull-Off Strength of Coatings Using PortableAdhesion Testers. This test method delin-eates a procedure for evaluating thedirect tensile strength (commonlyreferred to as adhesion) of a coating onsteel. The adhesion test consists of dolliesmade of aluminum, which are glued per-

an optical microscope to determine theextent of permeation. The margin of per-meation has been superimposed onto theimage pictured and tabulated at an aver-age of 21 mils (525 microns) DFT. Thiscalculates to 28% permeation of the totalfilm following S.W.A.T. exposure. Alower permeation percentage is tanta-mount to superior barrier protectionunder severe wastewater field condi-tions.

Physical TestingIn addition to the measurement of thepermeation resistance of a particular lin-ing system, the assessment of physicaleffects on the lining system is useful indetecting any significant changes a poly-mer may undergo as a result of severewastewater exposures. For example,physical testing can reveal whether thelining system loses its tensile or flexuralproperties and becomes embrittled fromexposure to these environmental condi-tions. When incorporated into theS.W.A.T., the quantitative determinationof these properties can be tracked at asmall fraction of the exposure time usu-ally required for these changes to be dis-cerned under actual field exposures. Twolaboratory tests used to measure tensilestrength and flexural strength can beused in a general way to assess a coat-ing’s suitability in wastewater. Thesemechanical properties are assessed bysubjecting coatings to an applied forceand determining their behavior under it.Any changes from the control (laborato-ry) condition are compared to the results

52 www.paintsquare.comJ P C L A p r i l 2 0 0 8

Fig. 10: Example of cracking on steel panels. Novolac epoxyliners following S.W.A.T. exposure.

Fig. 9: Example of blistering on steel panels. Coal-tar epoxy (left) andhigh-build amine epoxy liner (right) following S.W.A.T. exposure.

pendicular to the coated surface of thesamples. After the curing of the adhesive(glue), the testing apparatus is attached tothe loading fixture (dolly) and aligned toapply the tension (normal stress) to thetest surface. The force applied to the load-ing fixture is then gradually increasedand monitored until either a plug of coat-ing material is detached or a specifiedvalue is reached.Another method used to assess the

adhesion of the candidate lining systemsis the parallel scribe method, which isoften used with NACE TM0185Evaluation of Internal Plastic Coating forCorrosion Control of Tubular Goods byAutoclave Testing. This test method isconducted by making two cuts, 1⁄8 to 1⁄4 in.(3 to 6 mm) apart, through the coating tothe substrate (Fig. 8 on p. 49). Adhesionof the coating between the scribe marksis evaluated by prying the coating with autility knife and comparing the resultwith the rating scale below.

Although perhaps considered subjec-tive, the parallel scribe adhesion methodis useful in determining the adhesioneffects of undercut corrosion and blackrust that may not necessarily beobserved using ASTM D4541 direct ten-sile adhesion methods.Similar to the other mechanical test-

ing, the testing of adhesion properties isperformed prior to (control) and follow-ing exposure to the S.W.A.T. cabinet. Asignificant loss of adhesion is an indica-tion that the lining material is being per-meated and is affecting adhesion to thesubstrate at the bond line.

Visual InspectionThe last measure to determine the suit-ability of a candidate lining system forsevere wastewater is visual inspection.Visual inspection identifies any physicalalterations of a polymer following cabinet

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• A: No disbondment• B: >50% still attached• C: <50% still attached• D: No adhesion• F: Disbondment outside scribed lines

exposure to corrosive conditions. Forexample, the lining system is assessed forblistering, cracking, or rusting (pinpointor otherwise) of the coated panel.The rusting of the surface is assessed

in accordance with ASTM D610,Standard Test Method for EvaluatingDegree of Rusting on Painted SteelSurfaces.

Blistering is assessed in accordancewith ASTM D714, Standard TestMethod for Evaluating Degree ofBlistering of Paints. As seen in Fig. 9 (p.52), many protective coatings cannotwithstand the permeation of the corro-sive species found in severe wastewaterconditions and ultimately blister andcrack.

Any checking or cracking of the film isvisually identified on the steel and con-crete specimens. The extent of checkingor cracking can be identified as describedin ASTM D660, Standard Test Methodfor Evaluating Degree of Checking ofExterior Paints, and D661, Standard TestMethod for Evaluating Degree ofCracking of Exterior Paints. Figure 10 (p.52) shows two novolac epoxy liners thatcracked following S.W.A.T. exposure.

SummaryAsset management philosophy hasmunicipalities and water agencies lookingto protect their critical wastewater infra-structure from the destructive effects ofbiogenic sulfide corrosion with high-buildprotective linings. But where other ser-vices such as atmospheric or marinehave accelerated and other lab testsavailable, the wastewater coatings indus-try has not had suitable laboratory test-ing procedures to evaluate coatings forwastewater environments. Instead, theindustry has had to rely on anecdotalevidence as performance markers for useunder these corrosive conditions, andanecdotal evidence is not considered ade-quate to predict product performance.An accelerated Severe Wastewater

Analysis Test has been developed to sim-ulate severe wastewater headspace con-ditions. The S.W.A.T. protocol providesinterpretable data for product evaluationin fewer than 30 days. Manufacturers,recognized testing agencies, and technicalorganizations need to incorporate thisaccelerated cabinet protocol into theirevaluation programs when comparingmaterials for the protection of their criti-cal wastewater conveyance and treat-ment assets.

References1. O’Dea, Vaughn, “UnderstandingBiogenic Sulfide Corrosion,” MP(November 2007), pp. 36-39.

2. Nixon, R.A., “Coating SelectionGuidelines for Changing ExposureConditions,” JPCL (May 2001),

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pp. 42-58.3. Nixon, R.A., “Deterioration ofWastewater Treatment andCollection System Assets: KnowingWhere and How to Look,” PACE2006 Conference Proceedings, SSPC:The Society for Protective Coatings,Pittsburgh, PA (2006).

4. O’Dea, Vaughn, “Protecting

Wastewater Structures fromBiogenic Sulfide Corrosion,” JPCL(October 2007) pp. 52-56.

5. “No-Dig Technology Report,” NationalAssociation of Sewer ServiceCompanies (Owings Mills, MD: 1990).

6. Tnemec Company Inc. “TechnicalBulletin 03-41: A Novel Approachfor Evaluating Protective Coatings

Performance in WastewaterEnvironments,” Tnemec Company,Inc., Kansas City, MO (2002).

7. U.S. Environmental ProtectionAgency, “Detection, Control, andCorrection of Hydrogen SulfideCorrosion in Existing WastewaterSystems,” EPA/832/R92/001,Washington, D.C. (1992).

8. Redner, J.A., et al, “Evaluation ofProtective Coatings for Concrete”,Final Report, December 2004,County Sanitation Districts of LosAngeles County, 1986. (Updated:2004).

9. “Greenbook” Standard Specificationsfor Public Works Construction.BNi Building News, Vista, CA(2006 Edition).

10. Vincke, Elke, et al, “A New TestProcedure for Biogenic SulfuricAcid Corrosion of Concrete,”Biodegradation 10 (1999),pp. 421-428.

11. Briand, Remi and Randy Nixon, “ANovel Analytical Approach forEvaluating Protective CoatingsPerformance in WastewaterEnvironments,” WEFTEC 2003Conference Proceedings, WEFTEC(Alexandria, VA: WaterEnvironment Federation, 2003).

12. Baboian, Robert, Corrosion Tests andStandards: Application andInterpretation. (Fredericksburg, VA:American Society for Testing andMaterials, 1995).

13. U.S. Environmental ProtectionAgency, “Sewer and Tank SedimentFlushing: Case Studies,”EPA/600/R98/157, Washington,D.C. (1998).

14. Bowker, Robert P.G., John M. Smith,and Neil AWebster, Odor andCorrosion Control in SanitarySewerage Systems and TreatmentPlants, Noyes Data Corporation,Park Ridge, New Jersey (1989).

15. Tchobanoglous, George, et al.,Wastewater Engineering: Treatmentand Reuse (New York, NY: Metcalf

J P C L A p r i l 2 0 0 8 57www.paintsquare.com

WHY WASTE TIME BLASTINGTHICK & DIFFICULT COATINGS?

Our specialized induction machines typically remove thick anddifficult coatings from steel surfaces between 5 to 20 times fasterthan UHP or sandblasting. Removing coatings like vulcanized rub-ber, glassflake epoxies, fire protectants (like Chartek), tank linings,and anti-skid deck surfaces, is a piece of cake. The thicker andtougher the coating, the better. In addition to being fast, our ma-chines are virtually silent, and dust & waste free. This offers a muchsafer and more environmentally friendly alternative to blasting. Asyou read this you are probably full of questions and scepticism. Wewere too when we first started working with this technology 9 yearsago, but our combined 30+ years of working with paints led us tokeep looking for better solutions. No process is ideal in all situa-tions, but our induction machines work wonders on thick, toughcoatings. We challenge you, as a paint contractor or facility owner tolearn more about this process. You will be pleasantly surprised withhow well this works. We already have a number of major interna-tional oil companies, commercial contractors and even the US Navyas clients. This is proven technology. We urge you to check it out!

Visit the following webpage and register for a free DVD (containingvideos and brochures) that explains the RPR technology and showsour machines in actual use: www.RPRtech.com/JPCL

RPR Technologies, Oslo Norway(+47) 9139-0604 or Keizer Technologies

Americas (817) 685-7090 (www.rprtech.com)

The Measure of Quality

800-448-3835 or www.defelsko.comOgdensburg, New York USA • Tel: 315-393-4450Fax: 315-393-8471 • Email: techsale@defelsko.com

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& Eddy, Inc., 2002).16. Tchobanoglous, George, et al.,

Wastewater Engineering: Collectionand Pumping of Wastewater,(New York, NY: Metcalf & Eddy,Inc., 1981).

17. U.S. Environmental ProtectionAgency, “Odor and CorrosionControl in Sanitary SewerageSystems and Treatment Plants,”EPA/625/1-85/018, Washington,D.C. (1985).

18. Jones, Denny, Principles andPrevention of Corrosion. MacmillanPublishing Company, New York,NY (1992).

19. Loveday, D., et al., “Evaluation ofOrganic Coatings withElectrochemical ImpedanceSpectroscopy: Application of EISto Coatings, Part 1: Fundamentalsof Electrochemical ImpedanceSpectroscopy,” JCT CoatingsTech,1/8 (2004).

20. Loveday, D., et al., “Evaluation ofOrganic Coatings withElectrochemical ImpedanceSpectroscopy: Application of EISto Coatings, Part 2: Application ofEIS to Coatings” JCT Coatings Tech,1/10 (2004).

21. Loveday, D., et al, “Evaluation ofOrganic Coatings withElectrochemical ImpedanceSpectroscopy, Part 3: Protocols forTesting Coatings with EIS,” JCTCoatings Tech, 2/13 (2005).

22. Gray, Linda, KTA-Tator (Canada) Inc.,and Bernard Appleman, KTA-Tator,Inc., “EIS: A Tool to Predict RemainingCoating Life,” JPCL, (February 2003)pp. 66-74.

23. Polymer Science Learning Center,“Mechanical Properties ofPolymers” University of SouthernMississippi, 2005,http://www.pslc.ws/mactest/mech.htm (10 October 2007).

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