In Situ Thermal Treatment Lessons Learned

Transcription

1 In Situ Thermal Treatment Lessons Learned Jim Cummings Technology Innovation and Field Services Division OSRTI/OSWER/USEPA 22 nd Annual NARPM Training Program nd Annual nd Annual NARPM Training Program NARPM Training Program 1

2 Organization of Presentation National Perspective on In Situ Thermal Treatment Lessons Learned 2

3 In Situ Thermal Treatment Electrical Resistance Heating (ERH) Thermal Conductive Heating (TCH) Steam Enhanced Extraction (SEE) * * * * Radio Frequency Heating (RF) * * * * Self Sustaining Technology for Active Remediation (STAR) Gas Thermal Remediation (GTR) 3

4 National Perspective +/- 100 Completed In Situ Thermal projects - domestic and international (# growing) All vendors report being very busy May result in few(er) bids in response to RFPs (Grants, NM dry cleaner project had one bidder) 4

5 National Perspective (cont.) Variety of contaminants Low boiling point solvents Petroleum hydrocarbons High boiling point coal tars and PCB s Variety of unconsolidated and consolidated lithologies (Fractured rock, the Last Frontier ) Variety of conditions/situations Beneath (inhabited) buildings Considerable depth (c. 130 ) Below the water table 5

6 Attributes Effective across a wide range of permeabilities Thermal conductivity varies +/-2 over 10 6 permeability contrast Significant shortening of remedial timeframes In Situ Process Control Possible beneficial impacts on downgradient contamination No evidence of (dreaded) rebound 6

7 Sampler of Completed In Situ Thermal Projects at NPL and NPL-caliber sites Visalia, Ca NPL wood treater - SEE Delisted from NPL Pemaco, Ca Solvent NPL Site - ERH+ Camelot Cleaners, Fargo ND - ERH Tight clays Groveland Wells, Ma - ERH+SEE Silresim, Ma - ERH Grants, NM Drycleaner - ERH+ 7

8 Sampler On- Going/Planned/Prospective NPL caliber In Situ Thermal Projects Frontier Fertilizer, Ca (pesticides) - ERH SRSNE, Conn - TCH S Muni Water Supply Well site, Peterborough, NH - ERH+ Carter Carburetor, Mo. PCB - TCH(?) Wyckoff, Wa., wood treater - SEE/TCH 8

9 ERH Innovations 9

10 Angled Electrode Boring AF Plant 4 Photo Courtesy URS 10

11 Sheet Pile Electrodes 11

12 Horizontal Electrodes 12

13 Lessons Learned Actual performance often exceeds cleanup goals For ERH, need to add water adjacent to electrodes to prevent soil drying and ensure current flow Media conductivity (e.g., fill) may affect ERH applicability/performance For SEE, ensure proper closure of existing monitoring wells, etc. in treatment volume prior to heating (NOT hypothetical) 13

14 Lessons Learned Possible to heat discrete zones horizontally and vertically reduce treatment volume Systems can be installed entirely below grade No conflict w/ facility operations or pedestrian/vehicular traffic Subsidence rarely a problem But see Fargo, ND dry cleaner as main/only(?) exception Buried utilities, etc., usually not a problem (but see SRSNE) 14

15 Naphthalene Pipe Clogging 15

16 Lessons Learned Step 1 Check with local utility regarding power and equipment availability (and KEEP checking) Especially in areas undergoing development If there is a lot of contamination in the ground, you will recover it Have the (big) catcher s mitt ready Cummings rule of remediation mass = 2-5X estimated 16

17 Lessons Learned Specifying generic ISTT in RFP for CVOC sites will allow both ERH and TCH vendors to bid Hot sampling allows discontinuing heating of zones which have met cleanup goals Don t have to wait months for site to cool before demobilizing treatment equipment Concentrate power in zones not cleaning up as quickly A point about sustainability: Carbon footprint for electrically heating 1 yd 3 of contaminated soil digging and hauling it 65 miles (source: Terratherm) 17

18 Resources 18

19 EPA-542-R Mar 04 19

20 Resources/Contact Information Jim Cummings Eva Davis Web-based resources www. Frtr.gov In Situ Thermal Treatment of Chlorinated Solvents: Fundamentals and Field Applications EPA 540-R Mar 2004 In Situ Thermal Treatment Lessons Learned In preparation 20

21 Selective Heating Memphis Depot 22 22

22 Dunn Field, Memphis Depot, TN 8 DNAPL source areas, CVOCs 49,800 cubic yards (Semi-) Surgical remediation (Heron et al. 2009) 23

23 Aerial View of Memphis Site (During Demob) Central Treatment Equipment 367 heaters 68 extraction wells 24

24 New Kids on the Block 25

25 STAR Self-Sustaining Technology for Active Remediation In Situ Combustion Exothermic reaction converting carbon compounds CO 2 + H 2 O -Take advantage of BTU content of wastes Smoldering Flameless Occurs in porous materials Temperatures typically o C Propagation typically 5 ft/day Oxygen-limited, thus controllable 26

26 NAPL Smoldering Heating Element NAPL GROUNDWATER AIR SUPPLY HEATER OFF SOIL GRAINS 27 27

27 STAR Application 28 28

28 Pilot Results Pitt Consol DuPont Facility in NJ Post-pilot Soil Sampling Before After 29 29

29 Post-pilot Soil Sampling Compound STAR Pilot Results Average Concentration (mg/kg) Before STAR Treatment Combustion Zone T > 600 o C 2,4-Dimethylphenol Methylnaphthalene 7, Methylphenol Methylphenol Acenaphthene 3,950 6 Acenaphthylene Anthracene 16, Benzene 36 0 Benzo(a)anthracene Benzo(a)pyrene Benzo(b)fluoranthene Benzo(g,h,i)perylene Benzo(k)fluoranthene Carbazole 6,750 2 Chrysene Dibenzo(a,h)anthracene 60 0 Dibenzofuran 3,850 7 Ethylbenzene 40 0 Fluoranthene 3, Fluorene 5,150 7 Indeno(1,2,3-cd)pyrene Naphthalene 29, Phenanthrene 10, Pyrene 2,550 8 Toluene Xylenes (total) TPH-DRO soil C10-C28* 118, TPH-GRO soil C6-C10 1,300 7 Average Concentration Reduction = 99.72% Approximately 10,000 # of coal tar destroyed in situ Proceeding to full- 22 nd Annual 22 nd Annual NARPM NARPM Training scale Training Program Program 30

30 CLIQUEZ ET MODIFIEZ LE TITRE IN-SITU AND EX-SITU THERMAL DESORPTION APPLICATIONS GTR - Gas Thermal Remediation 31

31 How it Works Closed-loop in-situ thermal conductive heating system; More information at: Co-located vapor extraction and heating wells; Treatment temperatures from ~100 C to >400 C 32

32 Contaminants : Petroleum and Heavy Hydrocarbons Max. Concentration: 15,000 mg/kg Depth: 21 ft bgs Small Geology: Case Sand, Study: silt ISTT Underneath Volume: Building 400 m3 Treatment Time: 25 days Target Temperature: 200 C Challenges: Difficult access in basement; Rapid schedule RE transaction Remedial Goal: < 300 ppm Remedial Result: Avg. Concentrations < 90 ppm Both Performance and Time Guarantees Achieved Turnkey ISTD Cost: $168 / cu yd (note: larger areas generally less costly)

33 Reuse of TCH Wells: Geothermal Heat Storage Water in Water out When the commercial building was redeveloped to residential apartments, the heating wells were left in place and converted to geothermal heat storage wells with PTFE tubing. The system harnesses the constant temperature of the subsurface to preheat municipal water prior to the building s boiler system. The use of the wells in this manner also contributes to a more rapid reduction in in-situ soil temperatures. 34

34 Current, Select Small Projects (North America) Chlorinated Solvents: 900 cu yards ISTD (indoor installation) San Francisco 3,100 cu yards ISTD (active facility) Toronto BTEXs 2,700 cu yards ISTD (former petrol station) Sacramento 3,000 cu yards Ex-Situ Thermal Treatment in Wyoming PCBs 1,300 cu yards ISTD (to residential goals) in California Dioxins 1,900 cu yards Ex-Situ Thermal Treatment near Phoenix Coal Tar 2,500 cu yards ISTD (to residential goals) in Illinois 35

35 Part II: ISTD of PCBs at a Former Electrical Substation (Initial Pilot Study Results) 36

36 PCB Pilot Study (Commenced June 2012) Initial Soil Concentrations: Average 5,900 mg/kg (Aroclors 1242, 1260) Design Remedial Goal: Average samples < 10 mg/kg Design Duration > 250 C: 72 hours (64 days total heating duration) CEM: ambient air and emissions monitoring (reason for tent) Full Scale: project is > 10,000 cubic yards (combination of in situ and ex situ soils); estimated start date January 2013.

37 PCB Pilot Study (Vadose + Saturated Zones) Three Phases of Thermal Conduction Heating: First: Heating from ambient to boiling point of water (100 C) Second: Boiling, evaporation of groundwater in TTZ (steam stripping and removal of mobile DNAPL) Third: Superheating from 100 C to 250 C (thermal destruction of residual DNAPL)

38 PCB Pilot Study (Initial Results) Final results will be published in a scientific journal Spring Lessons Learned: 1. High temperature hydrolysis effected significant dechlorination of PCBs during remediation and likely acts as a positive polishing effect (more in our article). 2. Significant mass was extracted as NAPL and vapour off-gas. C3 Technology vapor condensation system specified for full scale treatment. 3. ND levels of dioxins and furans measured (low potential for indoor air quality impacts). Levels of dioxins and furans are now being measured in soil and groundwater for pre- vs. post-treatment quantification.

39 Cool (or Hot) New Idea Post-Remediation use of ISTT Infrastructure to support Geothermal Heat Pump for HVAC Considered for Frontier Fertilizer site but big box retailer decamped Reportedly part of plan post-istt at industrial facility in Bordeaux, France 40

40 Vendor Contact Information Additional Case Studies Terratherm - terratherm.com - Ralph Baker Thermal Remediation Services thermalrs.com David Fleming Current Environmental Solutions Cesiweb.com Joe Pezzullo McMillan-McGee Mcmillan-Mcgee.com Bruce McGee

41 Vendor Contact Information (cont.) RF Heating Ray Kasevich STAR Technology Gavin Grant, Geosyntec Gas Thermal Remediation TPS Tech America Grant Geckeler