Letty Arvide-Gomar, PE

Transcription

1 Letty Arvide-Gomar, PE

2 Outline DIP History and Applications Corrosion Issues Internal Cleaning Technologies Rehabilitation Options

3 DIP History and Applications Corrosion Issues Internal Cleaning Technologies Rehabilitation Options

4 DIP history dates back to the early 1800s 1 st CIP Horizontal, Molded Hot Dip Bituminous Lining/ Coating DI replaced CI in 50 s and 60 s 1 st DIP st CIP Vertical, Centrifugal 1 st Cement- Mortar Lining Ceramic Epoxy Lining

5 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

6 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

7 DIP History and Applications Corrosion Issues Internal Cleaning Technologies Rehabilitation Options

8 Acidic Condensate How corrosion occurs in pipes Air Pipe Wall Oxidation H 2 S Entering Air Water Level Oxygen Entering Water Wastewater Slime Layer Pipe Wall (typically 1 mm thick) Dissolution of Sulfide

9 Microbiologically-induced corrosion (MIC) cycle 1. Sulfate (SO 4 ) 4. Sulfuric Acid (H 2 SO 4 ) 2. Dissolved Sulfide (H 2 S) 3. Hydrogen Sulfide Gas (H 2 S)

10 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 (H 2 S) Low velocity increases solids deposition Turbulence promotes hydrogen sulfide release

11 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

12 Tuberculation buildup in DIP reduces pipe diameter

13 Tuberculation in DI sewer pipe increases friction and reduces capacity

14 DIP History and Applications Corrosion Issues Internal Cleaning Technologies Rehabilitation Options

15 Typical cleaning technologies may not remove tuberculation High-pressure water jetting (4,000 and 10,000 psi) equally distributed point-focus rotating flushing

16 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

17 High pressure water cleaning

18 Spinner/chain knocker cleaning Before After

19 DIP History and Applications Corrosion Issues Internal Cleaning Technologies Rehabilitation Options

20 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

21 Pipe Rehab/Replacement Methods Pipe Replacement Pipe Rehabilitation Point Repair Microtunneling Cured-in-Place Pipe (CIPP) Structural Sleeves Pipe Jacking Sliplining Joint Seals Horizontal Directional Drilling (HDD) Pipe Ramming Chemical Grouting/Flood Grouting Fold & Formed/ Formed Reformed CIPP Joint Grouting Impact Moling Spiral Wound Carbon Fiber Auger Boring Pipe Bursting Pipe Reaming Grout-in-Place Liners/Panel Liners Sprayed Carbon Fiber

22 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

23 CIPP Animation

24 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

25 UV-CIPP Animation

26 Pipe Bursting/Splitting for DI pipe Applications Benefits 4 to 54 diameter Gravity and pressure applications Uses roller blade cutters for non-fracturable pipe Upsize diameter Added capacity I/I elimination Long design life Challenges Access every 1,500 ft Bypass pumping required

27 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

28 Pipe Bursting Animation

29 Sliplining for DI pipe Applications Benefits 8 to 60 diameter Gravity and pressure applications Structural stability I/I elimination Long design life Challenges Reduces pipe diameter Access every 1,500 ft Bypass pumping required

30 Sliplining for DI pipe

31 Aged DIP causes collection system deficiencies Rehabilitation techniques CIPP and UV-CIPP Pipe Splitting Sliplining Replacement with new pipe

32 Summary

33 Questions? Letty Arvide-Gomar