1
Presented by: Steve Kebbe, P.E., Principal Engineer , Clean Water Services Susan M. Gierga, P.E., Murray, Smith & Associates, Inc.
PACIFIC NORTHWEST CLEAN WATER ASSOCIATION2010 ANNUAL CONFERENCE
October 24-27, 2010
2
PRESENTATION OVERVIEW
• Existing Facilities
• Evaluation
• Corrective Measures
3
CLEAN WATER SERVICES TREATMENT PLANTS
4
TWIN 24-INCH FORCE MAINS
5
FORCE MAIN COMPONENTS
Pipelines are plastic with the following exceptions:
• Fittings are ductile iron• Three creek crossings are ductile iron• Air release and vacuum valve assemblies have
metal components
6
CORRODED VALVE COMPONENTS
7
CORRODED THREADS
8
9
INSPECTION OF THE VAULTS
10
A SINGLE AIR RELEASE VALVE
11
TWO AIR RELEASE VALVES
12
TWO AIR RELEASE, TWO VACUUM BREAKERS
13
VENT WITHIN THE VAULT
14
VENT TO A NEARBY MANHOLE
15
VENT TO ODOR CONTROL CANISTERS
16
FINDINGS
• Corrosion within the vaults
17
CORROSION WITHIN THE VAULTS
18
CORROSION WITHIN THE VAULTS
19
CORROSION WITHIN THE VAULTS
20
CORROSION WITHIN THE VAULTS
21
CORROSION WITHIN THE VAULTS
22
FINDINGS
• Corrosion impacting the buried (metallic) components of the pipeline
23
CORROSION IMPACTING THE BURIED PIPE AND FITTINGS
24
CORROSION IMPACTING THE BURIED PIPE AND FITTINGS
25
FINDINGS
• Microbiologically Induced Corrosion (MIC)
26
MICROBIOLOGICALLY INDUCED CORROSION (MIC)
27
MICROBIOLOGICALLY INDUCED CORROSION (MIC)
28
CORROSION 101
Corrosion – The deterioration of a substance (usually a metal) because of an electrochemical reaction with its environment. External Corrosion Introduction to Chemistry and Control, Manual M27, AWWA.
29
CORROSION 101
ATOM
Ion – an atom that has lost or gained an electron.
Oxidation – the process of stripping electrons from an atom.
Reduction – the process of adding electrons to an atom.
30
CORROSION 101
Anion – an ion that has lost an electron (always negative) and therefore has a positive charge.
Cation – an ion that has gained an electron and therefore has a negative charge.
At least two types of IONS:
Positive Ion - Anion
Negative Ion - Cation
31
CORROSION 101
Anodic Process –
1.Positively charged ions (anions) leave the solid surface and enter into solution;
2.Anode – the point where the anion leaves the surface. This is the point where evidence of corrosion appears.
Cathodic Process –
1.Positively charged ions (anions) leave the solution and adhere to the metal surface.
2.Cathode - the point where the current returns to the metal from solution and protects it.
32
GALVANIC CORROSION
Galvanic corrosion can occurs whenever two or more dissimilar metals are in contact with each other while exposed to an electrically conductive liquid (such as sea water or rain water).
One metal corrodes preferentially when in electrical contact with a different type of metal.
The most reactive of the metals becomes corroded, in preference to the less reactive metal, which remains unaffected.
33
CORROSION 101
Four essential elements of any corrosion cell:
• There must be an anode;
• There must be a cathode;
• Both anode and cathode must be immersed in a conducting electrolyte;
• There must be a metallic conductor between the anode and the cathode.
34
THREE DISCRETE PROJECTS
1. Vault Replacement Project
2. Impressed Current Project
3. Buried Metallic Fittings Project
35
VAULT REPLACEMENT PROJECT
36
VAULT REPLACEMENT PROJECT
37
VAULT REPLACEMENT PROJECT
38
VAULT REPLACEMENT PROJECT
39
VAULT REPLACEMENT PROJECT
40
VAULT REPLACEMENT PROJECT
41
VAULT REPLACEMENT PROJECT
42
VAULT REPLACEMENT PROJECT
43
VAULT REPLACEMENT PROJECT
44
VAULT REPLACEMENT PROJECT
45
VAULT REPLACEMENT PROJECT
46
VAULT REPLACEMENT PROJECT
47
GALVANIC ANODE CATHODIC PROTECTION
48
IMPRESSED CURRENT PROJECT
49
IMPRESSED CURRENT PROJECT
50
IMPRESSED CURRENT PROJECT
51
IMPRESSED CURRENT PROJECT
52
IMPRESSED CURRENT PROJECT
53
IMPRESSED CURRENT PROJECT
54
IMPRESSED CURRENT PROJECT
55
IMPRESSED CURRENT PROJECT
56
IMPRESSED CURRENT PROJECT
57
IMPRESSED CURRENT PROJECT
58
IMPRESSED CURRENT CATHODIC PROTECTION
59
BURIED METALLIC FITTING PROJECT
60
SOIL RESISTIVITY/CORROSIVITY
61
BURIED METALLIC FITTING PROJECT
62
BURIED METALLIC FITTING PROJECT
63
BURIED METALLIC FITTING PROJECT
64
BURIED METALLIC FITTING PROJECT
65
BURIED METALLIC FITTING PROJECT
66
Presented by: Steve Kebbe, P.E., Principal Engineer , Clean Water Services Susan M. Gierga, P.E., Murray, Smith & Associates, Inc.
PACIFIC NORTHWEST CLEAN WATER ASSOCIATION2010 ANNUAL CONFERENCE
October 24-27, 2010
Top Related