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Letty Arvide-Gomar, PE
Outline
DIP History and Applications
Corrosion Issues
Internal Cleaning Technologies
Rehabilitation Options
DIP History and Applications
Corrosion Issues
Internal Cleaning Technologies
Rehabilitation Options
DIP history dates back to the early 1800s
1st CIP Horizontal,
Molded
1st CIP Vertical,
Centrifugal
Hot Dip Bituminous
Lining/ Coating
1st Cement-Mortar Lining
1st DIP
Ceramic Epoxy Lining
1816 1850 1860 1922 1955 1990
DI replaced CI
in 50’s and 60’s
Typical applications of DIP in sewer
• Gravity and pressurized systems
• Collection systems, lift stations, and treatment plants
• High groundwater table
• Deep excavations
• Unique applications
– Above water lines
– Replacing VCP
– Inverted siphons
– River and bridge crossings
DIP provides unique benefits for gravity sewer applications
• Long service life, durable
• High strength
– Traffic, deep bury, surge pressures
• Behaves as flexible conduit
• Resistant to differential settlement and seismic events
• Allows less inflow/infiltration
• Cost competitive
DIP History and Applications
Corrosion Issues
Internal Cleaning Technologies
Rehabilitation Options
(typically
1 mm thick)
Air
Wastewater
Acid
ic
Condensate
H2S Entering Air
Oxygen Entering Water
Water Level
Pipe
Wall
Slime
Layer
Pipe Wall Oxidation
How corrosion occurs in pipes
Dissolution of Sulfide
Microbiologically-induced corrosion (MIC) cycle
1. Sulfate (SO4)
2. Dissolved Sulfide (H2S)
3. Hydrogen Sulfide Gas
(H2S)
4. Sulfuric Acid (H2SO4)
Rate of corrosion is affected by wastewater in the collection system
• Low DO promotes anaerobic bacteria and sulfide generation
• High temperature increases microbial growth rate
• Low pH favors hydrogen sulfide gas (H2S)
• Low velocity increases solids deposition
• Turbulence promotes hydrogen sulfide release
Interior pipe linings offer abrasion resistance
• Design for velocities greater than 2 fps
• Apply ceramic epoxy interior pipe linings
– Tnemec Series 431 Perma-Shield
– Protecto 401
Tuberculation buildup in DIP reduces pipe diameter
Tuberculation in DI sewer pipe increases friction and reduces capacity
DIP History and Applications
Corrosion Issues
Internal Cleaning Technologies
Rehabilitation Options
Typical cleaning technologies may not remove tuberculation
• High-pressure water jetting (4,000 and 10,000 psi)
– equally distributed
– point-focus
– rotating
– flushing
Robust mechanical cleaning methods remove tuberculation but can damage pipe
• Cutters, milling machines, and chain knockers/ spinners
– Water pressure driven
– Designed to align within pipe
– Debris suction downstream
High pressure water cleaning
Spinner/chain knocker cleaning
Before After
DIP History and Applications
Corrosion Issues
Internal Cleaning Technologies
Rehabilitation Options
Pipe rehabilitation provides many benefits
1. Structural restoration
2. Reduction of Inflow and Infiltration (I/I)
3. Reduced O&M
4. Maximize benefit of existing asset
Pipe Replacement Pipe Rehabilitation Point Repair
Microtunneling Cured-in-Place Pipe
(CIPP) Structural Sleeves
Pipe Jacking Sliplining Joint Seals
Horizontal Directional
Drilling (HDD)
Chemical Grouting/Flood
Grouting CIPP
Pipe Ramming Fold & Formed/ Formed
Reformed Joint Grouting
Impact Moling Spiral Wound Carbon Fiber
Auger Boring Grout-in-Place
Liners/Panel Liners
Pipe Bursting Sprayed
Pipe Reaming Carbon Fiber
Pipe Rehab/Replacement Methods
Cured-in-Place Pipe (CIPP) for DI pipe
Applications
• 6” to 120” gravity sewer
• Thermosetting resins
• Hot water, steam, UV curing
• I/I elimination
• Structural restoration
Benefits
• Manhole installation*
• Navigates minor bends
• Minimal capacity reduction
• Can include carbon fiber
Challenges
• Pre-cleaning required
• Bypass pumping required
• Access every 1000 ft
*Depends on size to remove cone of manhole
CIPP Animation
Ultraviolet light CIPP (UV-CIPP) for DI pipe
Applications • 6” to 48” gravity sewers
• I/I elimination
• Structural restoration
Benefits • No water/steam for curing
• Fast curing time (10 ft/min)
• Stronger than traditional CIPP
• Pre-cure CCTV inspection
Challenges • Bypass pumping required
• Access every 1,000 ft
UV-CIPP Animation
Pipe Bursting/Splitting for DI pipe
Applications
• 4” to 54” diameter
• Gravity and pressure applications
• Uses roller blade cutters for non-fracturable pipe
Benefits
• Upsize diameter
• Added capacity
• I/I elimination
• Long design life
Challenges
• Access every 1,500 ft
• Bypass pumping required
Pipe splitting specifically designed for DI pipe
• Blade cutting wheel/roller configuration
• Split host pipe instead of ripping or tearing
• Requires less power than other static systems
• Clean process that protects damage of product pipe
Pipe Bursting Animation
Sliplining for DI pipe
Applications
• 8” to 60” diameter
• Gravity and pressure applications
Benefits
• Structural stability
• I/I elimination
• Long design life
Challenges
• Reduces pipe diameter
• Access every 1,500 ft
• Bypass pumping required
Sliplining for DI pipe
Aged DIP causes collection system deficiencies
• Rehabilitation techniques
– CIPP and UV-CIPP
– Pipe Splitting
– Sliplining
• Replacement with new pipe
Summary
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