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

Questions?

Letty Arvide-Gomar lgomar@carollo.com