T-CON: MIDWEST WATER AND WASTEWATER TECHNOLOGY CONFERENCE SUSTAINABILITY BEGINS WITH CATHODIC PROTECTION June 5, :00 AM 9:30 AM

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1 T-CON: MIDWEST WATER AND WASTEWATER TECHNOLOGY CONFERENCE SUSTAINABILITY BEGINS WITH CATHODIC PROTECTION June 5, :00 AM 9:30 AM Reprinted from Opflow, vol. 36, No. 5 (May 2010), by permission. Copyright 2010, American Water Works Association. Philadelphia Water Department Protection 1

2 Introduction Eric S. Langelund Cost of Corrosion How corrosion works Methods for corrosion control COST OF CORROSION There are 155,693 public water systems in the U.S. There are over 77,500 wastewater systems in the U.S. The average age of water/wastewater today is 41 years, of a 50 year design life. By 2020, 45% of all water/wastewater infrastructure will be in poor to elapsed life condition. Protection 2

3 COST OF CORROSION Based on percentage of GDP, the $36 billion 2002 annual cost of corrosion for water/wastewater is now in excess of $50.7 billion per year. Annual cost for corrosion in water/wastewater by state: California$4.6 billion Texas$4.4 billion New York$4.3 billion Florida$2.8 billion Illinois$2.3 billion COST OF CORROSION Average water loss nationally is 11%. Acceptable percentage of loss in California is 15%. Acceptable percentage of loss in Texas is 20%. Houston Metropolitan Area loses 83 million gallons of water to leaks per day. Nationally there are up to 75,000 sanitary sewer overflows (SSO) annually releasing up to 10 billion gallons of untreated wastewater into the environment. Protection 3

4 COST OF CORROSION According to the American Waterworks Association (AWWA) industry database, there is approximately 1,483,000 km (876,000 mi) of municipal water piping in the United States. COST OF CORROSION ANNUAL COST IN US UTILITIES = $47.9 B, 34.7% TRANSPORTATION = $29.7 B, 21.5% INFRASTRUCTURE = $22.6 B, 16.4% GOVERNMENT = $20.1 B, 14.6% PRODUCTION & MANUF. = $17.6 B, 12.8% TOTAL = $276,000,000,000.00!!! Protection 4

5 COST OF CORROSION PLEASE NOTE, $276 B = DIRECT COST INDIRECT COSTS PLANT DOWN TIME, DELAYS DURING BRIDGE REPAIR, ETC ENVIRONMENTAL CLEAN UP LOSS OF PRODUCT SALES, PIPELINE PRODUCT AND END PRODUCT INDIRECT COSTS ADD APPROX 3X TO DIRECT COST ESTIMATE TOTAL = $600 B PER YEAR!!! COST OF CORROSION WHERE DOES ALL THAT MONEY COME FROM? APPROX US POPULATION = 300 M ANNUAL COST PER PERSON = $2, PER PERSON, PER YEAR!!! FAMILY OF 4 = $8, Protection 5

6 Metals have different energy levels Active (negative) Nobel or Passive (positive) Gold (positive) Platinum Silver Copper Steel Aluminum Zinc Magnesium (negative) Protection 6

7 Fabrication of metals adds energy The metals want to return to their natural (ore) state Steel production involves processing iron ore with other metals and therefore steel is NOT pure iron (hold this thought) Four parts of corrosion, all of which are required Anode-corroding metal surface Cathode-non-corroding metal surface Metal Connection-path for electron energy transfer Electrolyte Connection-path for ionic energy transfer Protection 7

8 There are two basic forms of corrosion Naturally occurring Stray current Naturally occurring corrosion is galvanic and may be caused by Dissimilar metals Dissimilar electrolytes Oxygen concentration Galvanic corrosion process-metals corrode in an attempt to achieve a balance of energy Protection 8

9 Therefore, one metal corrodes to protect another Remember that steel is not pure? Through fabrication of steel the surface is left with anodic and cathodic areas The areas have a metallic connection All that is required for corrosion to occur is an electrolyte (rain or soil) Stray current Man made External source of DC current traversing through the soil (electrolyte) strays onto a structure DC powered transit systems Foreign cathodic protection systems Protection 9

10 Cathodic reaction (protection) occurs where the current is picked up on the structure Anodic reaction (corrosion) occurs where the current leaves the structure into the soil (electrochemical reaction) Stray current may be serious One ampere per year corrodes more than 20 pounds of steel! >5 of 2 pipe >1.75 of 4 pipe >1 of 6 pipe Protection 10

11 Methods of mitigating stray current Electrical bonding to return the current to its source eliminates the electrochemical reaction Sacrificial anodes may be used so that they experience the electrochemical reaction and are consumed instead of the structure (we ll discuss anodes shortly) Control One metal corrodes to protect another Galvanizing Examples Chain link fence Rock chip on car Protection 11

12 Control Chemical reaction of corrosion Fe = Fe e - Zn = Zn e - Mg = Mg e - Control Voltage 0 Cu Fe Zn -1.1 Mg -1.6 Protection 12

13 Control Current + Electrons Volts Resistance -- Conventional current flows positive to negative. Control Current flows from the pipe to the anode along the wire and from the anode back to the pipe through the earth. Protection 13

14 Control Iron Pipe Wire Wire Current Impressed Current Anode Electrons -- Rectifier + Current flows from the positive lug of the rectifier to the IC anode along the wire then through the earth to the pipe and returns to the rectifier negative lug along the wire. Control Control of Pipeline Corrosion, A.W. Peabody At the cathode, a surplus of electrons has arrived. These surplus negatively charged electrons combine with positively charged hydrogen ions from the environment to form hydrogen (H 2 ). This hydrogen is the basis of the polarization film commonly referred to in corrosion work. Protection 14

15 Control Coatings Not perfect Protect a large part of a structure Small flaws in the coating are referred to as holidays Control Effective corrosion control system Coating/wrapping system compatible with its environment Complete designed cathodic protection system Soil resistivity Current density Surface area of structure Environment and/or application Protection 15

16 Using Cathodic Protection Equipment Using Cathodic Protection Equipment Protection 16

17 Testing Cathodic Protection Systems Testing Cathodic Protection Systems Protection 17

18 Real Life Hot water heaters Boats Sardine cans What This Means Rust never sleeps Corrosion control is a proven science, US Navy, etc Remember, need to complete the circuit for corrosion to occur There is always more to learn about corrosion Protection 18

19 Next Steps Always use qualified personnel Corrosion people are ALWAYS willing to help We don t buy food and drinks, we rent them. PIPELINE INSTALLATION Protection 19

20 ANODE INSTALLATION RECTIFIER Protection 20

21 REMOTE MONITORING DAGB Protection 21

22 CONVENTIONAL GROUNDBED REVERSE CURRENT SWITCH Protection 22

23 DRAINAGE SWITCH ANODE IN HOLE Protection 23

24 WATER VALVE REPAIR BALAST TANK W/O CP Protection 24

25 BALAST TANK W/ CP GRAPHITIZATION Protection 25

26 PCCP COPPER Protection 26

27 CONTINUITY BOND CONTINUITY BOND Protection 27

28 WATER TANK W/O CP WATER TANK W/ CP Protection 28

29 CI and DI WALL THICKNESS ICE FREE CP SYSTEM Protection 29

30 TREATMENT EQUIPMENT POLYETHELENE Protection 30

31 CONTINUITY BONDS Protection 31

32 SAFETY FIRST Sustainability Begins With Cathodic Protection Catholic Protection Thank you all very much for attending the conference. Protection 32