THE ECOLOGICAL IMPLICATIONS OF TRENCHLESS PIPE REHABILITATION

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1 THE ECOLOGICAL IMPLICATIONS OF TRENCHLESS PIPE REHABILITATION Bridget Donaldson Research Scientist Virginia Transportation Research Council

2 Transportation Infrastructure Deterioration of pipes is a growing problem for transportation agencies $23 trillion in water and sewer infrastructure needs to be spent in next 23 yrs

3 Open cut: excavate old pipe Pipe Repair Trenchless: line old pipe without digging

4 Trenchless Technologies Four Main Categories: Sliplining Close-fit Liner Spray-on Liner Cured-in-Place Pipe Liner

5 Are there any environmental implications of these pipe repair methods for storm water pipes?

6 Trenchless Technologies Sliplining PVC or steel inserted into host pipe, space between host pipe and liner is grouted

7 Close-fit Liner Trenchless Technologies Folded liner, unfolds and expands to fit shape of damaged pipe

8 Trenchless Technologies Spray-on Liner Epoxy spray, hardens immediately to form a solid liner

9 Sliplining Trenchless Technologies Close-fit Liner Spray-on Liner Cured-in-Place Pipe Liner - Folded/flexible felt liner coated with resin, expands to fit shape of damaged pipe

10 Cured-in-Place (CIPP) Installations Common practice for lining damaged/worn utility pipes CIPP operations span the U.S. and 40 other countries Most common repair method for underground pipes, gained rapid popularity for culverts and storm water pipes

11 CIPP Methods Wet-out = resin impregnation: Resin hose Felt tube (liner) Coating

12 5. Inspect completed installation with camera Lining installation: Pump/Boiler 1. A resin-saturated liner enters the existing pipe by air or water pressure 2. Water or steam expands the liner and pushes it down the length of the existing pipe 3. Heated water or steam re-circulates and cures the resin 4. Cool-down period, then ends of cured liner are cut open

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14 Composition of Resin Unsaturated polyester resins Vinyl ester resins Epoxies Contain Styrene Styrene content: 30-50%

15 Styrene Synthetic chemical, volatizes quickly in water and air Priority pollutant (EPA), potentially carcinogenic Styrene from accidental releases of uncured resin from CIPP installations has caused fish kills Vapor from styrene in CIPP installations has entered buildings and homes and exceeded allowable exposure levels

16 Environmental Implications? Are there effects on water quality at project sites? Measures to ensure containment of resin Methods of curing water/steam disposal Permeability of coating on liner (can styrene leach after installation?) Resin Coating

17 Regulations for Styrene EPA s Maximum Contaminant Level (MCL) for styrene in drinking water is 0.1 mg/l (ppm) The EPA does not have published standards for allowable levels of styrene in receiving waters The discharge of pollutants is regulated (and would require an NPDES permit)

18 METHODS 7 sites in Virginia 3 companies Site County Route No. Pipe Size Spotsylvania Prince Edward Prince Edward Albemarle Nottoway Nottoway Nottoway Diameter (in) Length (ft) Observed 5 installations Sampled water at 7 sites

19 Water Sampling Collected water samples before and after installations (from pipe outlet to up to 40 m downstream) - Sampled until styrene no longer detected -

20 Cleaning host pipe and pre-install inspection Installation Observations

21 Temporary dams or stream diversion

22 Liner insertion

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25 Cutting Pipe Ends

26 Extruded Uncured Resin (580 mg/l)

27 Extruded Uncured Resin

28 What Concentrations of Styrene are TOO High?? MCL of styrene for drinking water: 0.1 mg/l none of the sites were directly linked to drinking water supplies No other U.S. (or VDEQ) regulations for styrene in water What levels harm aquatic life? Canada s regulations for toxins in discharged effluent: Effluent must be below the lethal limit for rainbow trout

29 Toxic Styrene Levels Aquatic Species LC 50 or EC 50 (mg/l) Water flea 48-hr EC 50 : 4.7 Amphipod 96-hr LC 50 : 9.5 Fathead minnow 96-hr LC 50 : 5.2 Rainbow trout 96-hr LC 50 : 2.5 Freshwater green algae 96-hr EC 50 : 0.72 LC 50 or EC 50 : concentration required to kill (LC 50 ) or have a defined effect on (EC 50 ) half of the study population

30 RESULTS Drinking water MCL: 0.1 Water flea EC 50 : 4.7 Rainbow trout LC 50 : 2.4 Styrene Concentrations During CIPP Installations (mg/l) Liner Insertion/Steaming Condensate Release Site Site Site 3-77

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32 Water Sampling Summary Styrene concentrations were detected up to 88 days after installation Highest concentration (77 mg/l) during effluent release Styrene concentrations at 5 of 7 sites exceeded the MCL (0.1 mg/l) of drinking water - These concentrations were above the MCL for 5 to 71 days after installation) - Concentrations above the MCL were detected up to 40 m downstream Styrene concentrations at 4 sites exceeded toxicity criteria for aquatic species - At one site these values were exceeded 24 days after installation

33 Observations after Installations Surface Residue

34 Algal blooms - Appeared within 6 to 8 days after installation, downstream only - Present at least 55 days after installation, up to 40 m downstream

35 Conclusions 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 lining material

36 Recommendations VDOT should suspend styrene-based CIPP and undertake additional study of its installation and use to gain a better understanding of the technology and its potential impacts. VDOT should evaluate their contract specifications to ensure that CIPP contractors are specifically required to prevent the escape or leaching of process residuals and to capture and properly dispose of residuals including cure water, cure steam condensate, and escaped resin. If styrene-based CIPP is reinstated, VDOT should also ensure that proper oversight is provided to ensure compliance with any revisions to the specifications.

37 VDOT Response VDOT immediately placed a stop work order on all styrene-based CIPP repair projects contracted by VDOT 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 stringent specifications for CIPP repair

38 VDOT Specifications VDOT project inspector must provide oversight Additional lining materials are required to ensure capture of extruded uncured resin Finished liner must be rinsed before reinstating water flow Cure water must be properly disposed Contractors must hire independent labs to test water before and after each project

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