The Environmental Implications of Road Culvert Repair Technologies. Bridget Donaldson Senior Research Scientist

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1 The Environmental Implications of Road Culvert Repair Technologies Bridget Donaldson Senior Research Scientist

2 Presentation Overview Culvert repair technologies Past and ongoing research by VCTIR Cured-in-Place Pipe repair study and resulting specifications Other lining technologies being evaluated 2

3 Pipe Repair In the U.S., $23 trillion in water and sewer infrastructure needs to be spent in next 20 yrs Pipe/culvert repair technology has grown rapidly Repair technologies originated for underground pipes 3

4 Culvert Repair Deterioration of culverts is an increasing problem for transportation agencies 4

5 Open cut Trenchless 5

6 Trenchless Technologies Six Main Categories: Slipliners Spiral wound liners Fold and form liners Spray-on liners Cured-in-place pipe liner Pneumatically applied concrete (Shotcrete) 6

7 Slipliners PVC or steel inserted into host pipe, annular space is grouted - Benefits: no chemicals or resins - Disadvantages: reduction in flow capacity 7

8 Spiral Wound Liners Sections of PVC wound and welded around spiraling machine, annular space grouted - reduction in flow capacity 8

9 Fold and Form Liners Folded liner, unfolds and expands to fit shape of damaged pipe - minimal reduction in flow capacity max diameter 9

10 Spray-on Liner Epoxy spray, solidifies immediately - Disadvantages: pipe must be completely dry, environmental issues? - Advantages: cures quickly, no reduction in flow capacity 10

11 Cured-in-place (CIPP) Liners Flexible liner coated with resin, expands to fit shape of damaged pipe, - minimal reduction in flow capacity - environmental issues 11

12 Pneumatically Applied Concrete Concrete application along culvert bottom - Raises bottom elevation (at least 4 in) 12

13 Costs Varies greatly depending on pipe and site conditions Longevity Lowest $ Highest $

14 VCTIR study: Are there any environmental implications of these pipe repair methods? 14

15 Trenchless Technologies Six Main Categories: Slipliners Spiral wound liners Concrete (Shotcrete) Spray-on liners Cured-in-place pipe liner Fold and form liners 15

16 Trenchless Technologies Six Main Categories: Slipliners Spiral wound liners Concrete (Shotcrete) Fold and form liners Spray-on liners Cured-in-place pipe liner Steel, PVC, HDPE + grout Increased enforcement of permitting regulations Entail a chemical transformation 16

17 Trenchless Technologies Six Main Categories: Slipliners Spiral wound liners Concrete (Shotcrete) Fold and form liners Spray-on liners Cured-in-place pipe liner Steel, PVC, HDPE + grout Increased enforcement of permitting regulations Entail a chemical transformation 17

18 Trenchless Technologies Fold and form liners Spray-on liners Cured-in-place pipe liner Lab study (2009) found no env effects, would like to evaluate in field Will be evaluated this year 18

19 Cured-in-place Pipe Repair CIPP operations span the U.S. and 40 other countries Most common repair method for underground pipes Repair method used by nearly all U.S. DOTs, and for approx 1/2 of VDOT s culvert repair projects before

20 CIPP (conventional) A resin-saturated felt liner is pulled or inverted through host pipe Water or steam inflates the liner, conforms to shape of host pipe Heated water or steam re-circulates and cures the resin Cool-down period, then ends of cured liner are cut open 20

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22 CIPP (conventional) Resin is 30-50% styrene Styrene is an EPA priority pollutant, potentially carcinogenic - Max Contaminant Level (MCL) for drinking water: 0.1 mg/l Styrene from uncured resin from CIPP installations has caused fish kills (FL, Canada) and damaged water treatment plants - Toxicity level for rainbow trout: 2.2 mg/l Vapor from styrene in CIPP installations has entered buildings and homes and exceeded allowable exposure levels 22

23 CIPP study (VCTIR) Monitored 7 CIPP installations in VA Collected water samples before, during, and after installations 23

24 CIPP Observations: Discharge of hot cure water Uncured extruded resin Algal blooms 24

25 CIPP Water Sampling Test Results Styrene concentrations were as high as 77 mg/l and were detected up to 88 days post installation times the MCL for drinking water - 31 times toxicity values for rainbow trout and water flea Styrene concentrations exceeded the toxicity values of the rainbow trout and water flea at four of the seven monitored project sites (for up to 24 days post installation) 25

26 CIPP Styrene concentrations detected in water samples resulted from one or a combination of the following: Installation practices that did not capture condensate containing styrene Uncured resin that escaped from the liner during installation Insufficient curing of the resin Some degree of permeability in the felt lining material 26

27 CIPP: VDOT Response VDOT immediately placed a stop work order on all styrene-based CIPP repair projects contracted by VDOT (2007) A VDOT task group led by VDOT s Environmental Division was formed to evaluate further the use of steam- and water-cipp repair projects containing styrene VDOT developed new specifications for CIPP repair 27

28 VDOT s CIPP Specifications VDOT project inspector must provide oversight Thermocouples required during installation Additional lining materials are required to ensure capture of extruded uncured resin Finished liner must be rinsed before reinstating water flow Cure water and rinse water must be captured and disposed Contractors must hire independent labs to test water before and after each project New York State DOT has also issued new CIPP specifications California has reduced its use of CIPP 28

29 Other CIPP Methods being Evaluated Epoxy (styrene-free) CIPP - small amount of uncured, extruded resin observed - some samples exceeded aquatic species toxicity thresholds - water volume and dilution have important effect on chemical concentrations 29

30 UV-CIPP (styrene) - Uses 1/3 of the resin as compared to conventional method - Fiberglass liner, inner and outer impermeable foil - Produces no effluent 30

31 UV-CIPP Preliminary test results: Many samples were non-detect, but some exceeded aquatic species toxicity thresholds 31

32 Recommended Considerations for New Lining Products Field-test and monitor new products before approval Detailed specifications for projects requiring resin or spray - rinse liner, capture and dispose of effluent and rinse water, test water samples after installation Installation oversight with trained inspectors 32

33 Final VCTIR report will be available 2012 Will include information to assist with pipe repair product selection and specification development 33