Severe Wastewater Testing Program for Rapid Evaluation of Manhole Linings

Transcription

1 Vaughn O Dea, HWEA Severe Wastewater Testing Program for Rapid Evaluation of Manhole Linings Vaughn O Dea, Tnemec Company, Inc.

2 Vaughn O Dea, HWEA PRESENTATION OVERVIEW Severe Wastewater Environments municipal wastewater conditions biogenic sulfide corrosion protective coating failures Severe Wastewater Testing Program for Rapid Evaluation of Coatings & Linings laboratory testing protocol material selection metric for manhole protection

3 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS MUNICIPAL WASTEWATER COMPOSITION Contains approximately 99% water Pathogenic & non-pathogenic bacteria Organic & inorganic particles Macro-solids May contain emulsions or solvents ph (typical) May become septic --not corrosive to concrete

4 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS BIOGENIC SULFIDE CORROSION Deterioration of manholes, lift stations, sewer interceptors occurring at an alarming rate Biogenic sulfide corrosion process Headspace (vapor phase) environments above flow of the waste stream Increased levels of hydrogen sulfide (H 2 S) Presence of carbon dioxide (CO 2 ), methane (CH 4 ) Permeation-induced failures of high-performance protective coatings

5 Deteriorated Manholes, typical Vaughn O Dea, HWEA

6 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS BIOGENIC SULFIDE CORROSION Biological oxidation of H 2 S to H 2 SO 4 within headspace areas of enclosed wastewater structures Simplified equation for the biological metabolic process converting hydrogen sulfide to sulfuric acid: H 2 S + 2O 2 Thiobacillus SOB H 2 SO 4 H 2 SO 4 attacks the matrix of the concrete above the waterline (i.e., pipe crowns, walls, soffits) Commonly composed of calcium silicate hydrate gel, calcium carbonate from aggregates (when present), and un-reacted calcium hydroxide Less than 7% concentration, theoretical

7 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS Collection System: manholes

8 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS Collection System: lift stations

9 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS Collection System: lift stations

10 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS Collection System: sewer interceptors

11 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS Treatment Facility: influent channels

12 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS Treatment Facility: grit chambers

13 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS Treatment Facility: primary treatment structures

14 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS PROTECTIVE COATING FAILURES H 2 S and CO 2 are produced in association with CH 4 and NH 3 in sewer environments Increased H 2 S, CO 2, CH 4 levels Traditional protective coatings routinely failing Coal-tar epoxies (CTE s) Thin-film epoxies (e.g., polyamides, polyamidoamines, polyamines) High-solids, high-build protective linings NOT performing 100% solids polyurea elastomers 100% solids polyurethane elastomers Certain 100% solids, high-build epoxies (formulation specific)

15 Vaughn O Dea, HWEA COATING FAILURES coal tar epoxy

16 Vaughn O Dea, HWEA COATING FAILURES 100% solids pure polyurea elastomer

17 Vaughn O Dea, HWEA COATING FAILURES 100% solids, high-build epoxy liner

18 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS PROTECTIVE COATING FAILURES Historically considered chemical resistance as primary quality for sewer protection Sanitation Districts of Los Angeles County (LACSD) Standard Specifications for Public Works Construction (Greenbook) Chemical Resistance (Pickle-Jar) Test Recent study considers permeability to corrosive substances as predominant factor in sewer protection Sewer gases

19 Vaughn O Dea, HWEA SEVERE WASTEWATER ENVIRONMENTS THE DILEMMA Protection of wastewater infrastructure is of increasing concern among engineers and owners Recent spike in material offerings marketed for severe wastewater infrastructure protection Shortage of testing to substantiate permeation performance of such materials under severe wastewater headspace conditions Often relying on unsubstantiated claims for product suitability

20 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST (S.W.A.T.) CHAMBER TESTING Accelerated testing chamber provides comparative field results Provides a standardized method for the evaluation of a coating s performance under specific corrosive conditions Yields interpretable performance results in fraction of time

21 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST (S.W.A.T.) ACCELERATED WASTEWATER CHAMBER Developed in 2000 by coalition of industry experts Simulates & accelerates conditions characteristic of severe wastewater headspace environments Standard procedure for testing the durability of manhole linings applied to steel & concrete substrates WEFTEC 2003 PACE 2007 UCT S.W.A.T. chamber in fume hood

22 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PARAMETERS Laboratory Chamber Comprising: 1. Liquid Phase 2. Vapor Phase S.W.A.T. Chamber

23 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PARAMETERS, cont. 1. Liquid Phase: 10% H 2 SO 4 : slightly above maximum theoretical biogenic secretion levels 0.4% NaCl: to duplicate water intrusion experienced in coastal areas and to increase solute conductivity H 2 S (saturated): from sparging the gas through the solution Testing specimens lowered into aqueous solution for 15 min. 3 times per day. Raised to vapor phase balance of time

24 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PARAMETERS, cont. 2. Vapor Phase: 500 ppm H 2 S Permeation by sewer gases found to alter barrier film properties Contributes to blistering and cracking of protective coatings 500 ppm level is realistic exposure Prior work found this level paralleled elevated concentrations Other sewer gases (e.g., CO 2, CH 4 ) incorporated upon further field research Chamber purged (recharged) with sewer gas daily

25 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PARAMETERS, cont. Temperature: 65 C (150 F) The average temperature of wastewater in the US is between C (50-70 F) Chamber temperature accelerates reaction rate 4-5 times actual wastewater headspace conditions

26 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PARAMETERS, cont. Duration: 28 days 60 immersions and 20 gas purges Duration coincident with field failures of protective coatings Example CTE following S.W.A.T. (left) v. field exposure (right)

27 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE Performance measures based upon retained properties with regard to: A. Permeability B. Physical Testing C. Visual Inspections Coated Testing Specimens

28 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. A. Permeability Coatings act as a barrier separating the substrate from the corrosive service environment Low permeability to salts, water, gases, acids and other corrosive species are desired Measured via: 1. Electrochemical Impedance Spectroscopy (EIS) Analysis 2. Optical Microscopy Measurements

29 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. 1. Permeability: EIS Analysis Technique for evaluating permeability based on the electrical resistance (impedance) of the coating Logarithmic impedance scale derived from a large body of literature of laboratory and field work Higher and more stable the retained impedance, the better the long-term permeability resistance & overall coating performance EIS readings taken before/after cabinet exposure Polymer degradation is easily detected by a decrease in the measured impedance

30 Vaughn O Dea, HWEA Electrochemical Impedance Spectroscopy Analysis

31 Vaughn O Dea, HWEA EIS: CORROSION PROTECTION OF ORGANIC COATINGS Increasing Protection Poor Protection Begins Good Excellent Coating Impedance, Log Z (Z 0.1 Hz Ω-cm 2 ) Source: Gray, Linda EIS: A Tool to Predict Remaining Coating Life, JPCL, February 2003.

32 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. Permeability: EIS Analysis Product A: coal tar epoxy (CTE) Product B: novolac epoxy (NEP) Product C: high-build amine epoxy (HBEP) 98% Retained Impedance (2)%

33 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST EIS Analysis: Coating Impedance, Log Z Initial 28 day (15) % (29) % (37) % Product A Product B Product C Product D High-Build Epoxy Mortars (43) % 5.8

34 SEVERE WASTEWATER ANALYSIS TEST EIS Analysis: Coating Impedance, Log Z Initial 28 day Vaughn O Dea, HWEA (2)% (10) (15) % % (100) Product A Product B Product C Product % D High-Build Epoxy Liners 0

35 SEVERE WASTEWATER ANALYSIS TEST EIS Analysis: Vaughn O Dea, HWEA Coating Impedance, Log Z Initial 28 day (2) % Product A FR Epoxy Liners (37) % Product B 7.3

36 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. 2. Permeability: Optical Microscopy Assessment of permeation by microscopically observing the cross section of the coating film from concrete cylinder Permeation typically manifests as discoloration when viewed with 100X microscope with digital imaging

37 Vaughn O Dea, HWEA OPTICAL MICROSCOPY ANALYSIS Typical concrete cylinder coated with candidate systems N.T.S. Concrete cylinder cross section

38 Vaughn O Dea, HWEA OPTICAL MICROSCOPICY ANALYSIS, cont. 100% Solids Epoxy Mortar Observation: Total DFT 183 dft mils (avg.) Permeation: 71 mils (avg.) Permeation: 39%

39 Vaughn O Dea, HWEA OPTICAL MICROSCOPICY ANALYSIS, cont. 100% Solids Epoxy Liner Observation: Total DFT: 59 dft mils (avg.) Permeation: 5.5 mils (avg.) Copyright, Permeation: Tnemec Company, 9% Inc.

40 Vaughn O Dea, HWEA OPTICAL MICROSCOPICY ANALYSIS, cont. 100% Solids Epoxy Liner Observation: -Not attempted Permeation: 100%

41 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. 2. Physical Testing Any physical effects on the lining system are useful in detecting any significant changes a polymer may undergo as a result of exposure Commonly used laboratory tests to measure physical properties: Tensile Strength Testing Flexural Strength Testing Adhesion Testing

42 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. Physical Testing: Tensile Strength ASTM C306 ASTM D638 ASTM D2370 Elastomeric Polyurea

43 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. Physical Testing: Flexural Strength ASTM C580 ASTM D % solids, High-build Epoxy Mortars

44 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST Physical Properties: ASTM C 307 Tensile Strength ASTM C307 Tensile, psi Initial S.W.A.T (13) (36) (29) % % Product A Product B Product % C High-Build Epoxy Mortars

45 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST Physical Properties: ASTM C 580 Flexural Strength ASTM C580 Flexural, psi Initial S.W.A.T (18) (41) (40) % % Product A Product B Product % C High-Build Epoxy Mortars

46 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. Physical Testing: Adhesion ASTM D4541 Parallel scribe adhesion borrowed from NACE TM0185 Example of parallel scribe adhesion test on Polyurethane (hybrid) fast-sets Rating: D Rating: B

47 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. 3. Visual Inspection Identifies any physical alterations of a polymer following chamber exposure to corrosive conditions Assessed for: Rusting Blistering Checking/Cracking

48 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. Visual Testing: Rusting ASTM D610 Pinpoint rusting of a 100% solids, high-build amine epoxy liner

49 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. Visual Testing: Blistering ASTM D714 Left: Example of blistering of a coal-tar epoxy Right: Example of blistering of a 100% solids, high-build amine epoxy

50 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING PROCEDURE, cont. Visual Testing: Checking/Cracking Identified as described in: ASTM D660 ASTM D661 Left: Example of checking of a Polyurea Elastomer; Middle/Right: Example of cracking of Novolac Epoxies

51 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING RESULTS Results obtained are a means for estimating the protective barrier qualities of a protective lining under severe wastewater headspace conditions provides interpretable & comparative results in 28-days Copyright, Tnemec Company, Name of Laboratory: Inc. City, State, Country Name of Engineer: Rapid Evaluation of Coatings and Linings by Severe Wastewater Analysis Test Manufacturer: Product Trade Name: Address: Product Generic Description: City, State, Zip: Contact: Surface Preparation: Steel Concrete Resurfacer (if applicable): Primer (if applicable): RESULTS OF ANALYSIS Dry-Film Thickness (DFT): Control Sample 1 Sample 2 Sample 3 Steel Specimens Concrete Specimens Permeability Control Sample 1 Sample 2 Sample 3 Steel Specimens Electrochemical Impedance Log Z (@0.001Hz) Spectroscopy (EIS) Avg. Concrete Specimens Optical Microscopy Permeation N/A % Permeation N/A Grand Avg. Physical Testing Control Sample 1 Sample 2 Sample 3 Steel Specimens Tensile Adhesion Parallel Scribe Adhesion Concrete Specimens Parallel Scribe Adhesion Grand Avg. Grand Avg. Grand Avg. Tensile Strength Run 1 Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Control Specimens Grand Avg. S.W.A.T. Specimens Grand Avg. Flexural Strength Run 1 Run 2 Run 3 Run 4 Run 5 Run 6 Run 7 Control Specimens Grand Avg. S.W.A.T. Specimens Grand Avg. Visual Testing Steel Specimens Control Sample 1 Sample 2 Sample 3 Blistering (ASTM D 714) Rusting (ASTM D610) Checking (ASTM D 660) Cracking (ASTM D 661) Date of Sample Receipt: Date of Report: Name of Responsible Manager:

52 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST SUMMARY Laboratory testing procedure to rapidly evaluate protective coatings in simulated severe wastewater headspace environments vapor phase with sewer gases and corrosives accelerated testing procedure interpretable data in 28 day period Material evaluation for: permeability physical testing visual inspections Ongoing work to extrapolate service life predictions to support asset management approach

53 Vaughn O Dea, HWEA SEVERE WASTEWATER ANALYSIS TEST TESTING FACILITIES RAE Engineering Edmonton, Alberta Corrosion Probe, Inc Centerbrook, CT

54 Vaughn O Dea, HWEA REFERENCES 1. ASTM C307, Standard Test Method for Tensile Strength of Chemical-Resistant Mortar, Grouts, and Monolithic Surfacings, (West Conshohocken, PA: ASTM). 2. ASTM C580, Standard Test Method for Flexural Strength and Modulus of Elasticity of Chemical- Resistant Mortars, Grouts, Monolithic Surfacings, and Polymer Concretes, (West Conshohocken, PA: ASTM). 3. ASTM D610, Standard Test Method for Evaluating Degree of Rusting on Painted Steel Surfaces, (West Conshohocken, PA: ASTM). 4. ASTM D638, Standard Test Method for Tensile Properties of Plastics, (West Conshohocken, PA: ASTM). 5. ASTM D660, Standard Test Method for Evaluating Degree of Checking on Exterior Paints, (West Conshohocken, PA: ASTM). 6. ASTM D661, Standard Test Method for Evaluating Degree of Cracking on Exterior Paints, (West Conshohocken, PA: ASTM). 7. ASTM D714, Standard Test Method for Evaluating Degree of Blistering of Paints, (West Conshohocken, PA: ASTM). 8. ASTM D790, Standard Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials, (West Conshohocken, PA: ASTM). 9. ASTM D2370, Standard Test Method for Tensile Properties of Organic Coatings, (West Conshohocken, PA: ASTM). 10. ASTM D4541, Standard Test Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers, (West Conshohocken, PA: ASTM). 11. Bowker, Robert P.G., et al. Odor and Corrosion Control in Sanitary Sewerage Systems and Treatment Plants,. USA: Noyes Data Corporation, 1989.

55 Vaughn O Dea, HWEA REFERENCES 12. Briand, Remi and R.A. Nixon, A Novel Analytical Approach for Evaluating Protective Coatings Performance in Wastewater Environments (WEFTEC 2003 Conference Proceedings), October Design Manual Odor and Corrosion Control in Sanitary Sewerage Systems and Treatment Plants, EPA/625/1-85/018. Washington, D.C.: U.S. Environmental Protection Agency, Hydrogen Sulfide Corrosion in Wastewater Collection And Treatment Systems: Report to Congress, EPA/430/9-91/010. Washington, D.C.: U.S. Environmental Protection Agency, Joyce, J., An Overview of Methods and Approaches for Estimating and Solving Odor and Corrosion Problems in Collection Systems. Odor and Corrosion: Prediction and Control in Collection Systems and Wastewater Treatment Plants, Water Environment Federations (2001). 16. Gray, Linda and Bernard Appleman, EIS: A Tool to Predict Remaining Coatings life, Journal of Protective Coatings and Linings, (February 2003) pp Hydrogen Sulfide Corrosion in Wastewater Collection And Treatment Systems: Report to Congress, EPA/430/9-91/010. Washington, D.C.: U.S. Environmental Protection Agency, Joyce, J., An Overview of Methods and Approaches for Estimating and Solving Odor and Corrosion Problems in Collection Systems. Odor and Corrosion: Prediction and Control in Collection Systems and Wastewater Treatment Plants, Water Environment Federations (2001). 19. Loveday, D., et al, Evaluation of Organic Coatings with Electrochemical Impedance Spectroscopy: Application of EIS to Coatings Part 1: Fundamentals of Electrochemical Impedance Spectroscopy, JCT Coatings Tech, 1/8 (2004). 20. Loveday, D., et al, Evaluation of Organic Coatings with Electrochemical Impedance Spectroscopy: Application of EIS to Coatings Part 2: Application of EIS to Coatings, JCT Coatings Tech, 1/10 (2004). 21. Loveday, D., et al, Evaluation of Organic Coatings with Electrochemical Impedance Spectroscopy: Application of EIS to Coatings Part 3: Protocols for Testing Coatings with EIS, JCT Coatings Tech, 2/13 (2005).

56 Vaughn O Dea, HWEA REFERENCES 22. Neville, A.M. Properties of Concrete. Fourth Edition., J. Wiley, New York, NY, Nixon, R.A., Deterioration of Wastewater Treatment and Collection System Assets: Knowing Where and How to Look, (PACE 2006 conference proceedings), February New Survey Shows Permeability a Critical Corrosion Factor, WaterOnline 7 Nov. 2006: n. pag. Online. Available: O Dea, Vaughn, Protecting Wastewater Structures From Biogenic Sulfide Corrosion, Journal of Protective Coatings and Linings (October 2007), pp O Dea, Vaughn, Understanding Biogenic Sulfide Corrosion, Materials Performance (November 2007), pp O Dea, Vaughn, Spare the Concrete: Understanding the Mechanisms of Biogenic Sulfide Corrosion Can Lead to Solutions, Public Works Magazine (April 2007), pp O Dea, Vaughn, Lining Prevents Biogenic Sulfide Corrosion in Wastewater Systems, Materials Performance (May 2007), pp O Dea, Vaughn, et al., Assessing Coatings & Linings for Wastewater: Accelerated Test Evaluates Resistance to Severe Exposures, Journal of Protective Coatings and Linings (April 2008), pp Tchobanoglous, George, et al., Wastewater Engineering: Collection and Pumping of Wastewater, (New York: NY: Metcalf & Eddy, Inc. 1981). 31. Tnemec Company, Inc. Technical Bulletin 03-41R2: A Novel Approach for Evaluating Protective Coatings Performance in Wastewater Environments, Kansas City: Tnemec Company, Inc., Yongsiri, C., et al., Influence of Copyright, Wastewater Tnemec Constituents Company, on Hydrogen Inc. Sulfide Emission in Sewer Networks. Journal of Environmental Engineering ASCE (December 2005).

57 Thank You