Applications of In-Situ Chemical Oxidation/Reduction. Jay Romano

Transcription

1 Applications of In-Situ Chemical Oxidation/Reduction Jay Romano Manager Redox-Tech NE Environmental Business Council of New England Energy Environment Economy

2 Redox Tech, LLC Fundamentals of In-Situ Remediation Providing Innovative In Situ Soil and Groundwater Treatment 2

3 Redox Tech, LLC Business founded in Headquarters in Cary, NC. Other offices in GA, SC, IL, MA, and CA. New England Office opened in In situ treatment with biological and chemical manipulation, both reduction and oxidation over 800 projects completed. In situ Soil Blending. 3

4 In Situ Remediation is a TOOL!

5 Site Characterization for In Situ Treatment Designs Horizontal and Vertical Delineation; MNA Field Measurements (Ph, ORP, and DO); Alkalinity, Dissolved Iron, Sulfate, etc Site Geology; Total Oxidant Demand (TOD); Utility Locations; and Nearby Receptors.

6 In Situ Remediation The Design Delivery and Chemistry are Key Requires fundamental understanding of geochemistry and microbiology. Requires confidence in the consultants work. Requires delivery that mimics the target contaminant distribution. Without both proper data, delivery and formulation, remediation likely to fail. May require Pilot Study. 6

7 Total Oxidant Demand (TOD) Water-phase contaminant is not only material that will be oxidized Sorbed phase contaminant Free-phase contaminants Naturally-occurring organic material (NOM) Reduced soil and water minerals Can be estimated with site data 7

8 Total Oxidant Demand Total Oxidant Demand can vary between <0.1 to 155 g/kg 8

9 Treatment Classes Chemical Oxidation Chemical Reduction Aerobic Bioremediation Anaerobic Bioremediation Metals Stabilization Thermal (steam) 9

10 Chemical Oxidants Permanganate widely used for chlorinated alkenes, PCE, TCE, DCE, VC Peroxide (Fenton s) relatively inexpensive, but can be difficult to inject Persulfate replacing many peroxide applications because of safety and gas generation Ozone still occasionally used for gas stations 10

11 Base Activated Sodium Persulfate Competes with permanganate, Fenton s chemistry, ozone and peroxide; Oxidizes a broader range of organic contaminants than permanganate ; Oxidizes more compounds than Fenton s chemistry and does not have gas generation; Slower reaction time than other oxidants which can translate to less rebound; and Much safer to handle than other oxidants.

12 Sodium Persulfate Injection Enfield, CT Gasoline Release in the 1980s; Remediation activities included product recovery, SVE, pump and treat and soil excavation; Following 20+ years of remediation, groundwater concentration were still elevated under the roadway and nearby properties; and Redox Tech NE was invited to bid on a Fenton s Reagent design and proposed activated sodium persulfate as an alternative.

13 Injection Design 17,000 square foot treatment area; Average TVOC approximately 18,000 ppb; 5 to 7 foot thickness; 44 injection points (2 rounds); 54,000 lbs of sodium persulfate; 450 gallons per point; 2 target depth intervals; and Completed in 11 days;

14 Groundwater Treatment Results Average TVOC approximately 4,000 ppb (78%); Elevated sulfate still present in groundwater (>1,000 mg/l); and 22 out of 36 target monitoring wells below groundwater standards (GW Protection and Residential).

15 Redox Tech s Oxygen BioChem (OBC) A slow-release oxygen generating formula designed to provide short-term chemical oxidation (1-2 months) and long term anaerobic oxidation via sulfate reduction (1-2 years) Patented combination of sodium persulfate and food grade calcium peroxide Can be added to excavations or injected into groundwater One of the preferred products in New Hampshire Predecessor to Klozur CR

16 Oxygen BioChem vs. Competitors Oxygen BioChem (OBC) Competitors Greater oxygen as much as 46 wt % Both chemox and biorem. Typically 10 to 20 wt % Mostly bioremediation Greater solubility 40 wt % for the persulfate portion Better value - $3.25 per pound Typically less than 5% soluble Typically $4 to $10 per pound

17 Enhanced Anaerobic Bioremediation Aquifers are sometimes limited by carbon (or food) source for bacteria In some instances, the proper bacteria (e.g. dehalogenators) are not present Overstimulation can result in domination by methanogens Examples: Redox Tech s ABC, FMC s EHC and Regenesis HRC Data should support the use of these products 17

18 Sodium Lactate Anaerobic BioChem (ABC) Ethyl Lactate green solvent Fatty Acids all dissolved Dipotassium Phosphate for micronutrients and ph buffering Can bioaugment with RTB-1 (DHC) 18

19 ABC Advantages Long lasting (2+ years) but water soluble so large volume of chase water not required Lower injection pressures Does not require hydrolysis of oils to release fatty acids No emulsion breaking potential No soap formation from bringing ph up to high Demonstrated buffering 19

20 Anaerobic BioChem (ABC + ) Mixture of ABC plus zero valent iron (ZVI) Combination of chemical reduction (ZVI) and anaerobic bioremediation Less likely to form VC Licensed with Adventus & Waterloo to add ZVI to carbon amendment Injected over 1,500,000 pounds ABC+ 20

21 ZVI REACTION β-elimination pathway minimizes daughter products very low concentration of chlorinated intermediates intermediates degrade Surface reaction at ZVI 21

22 Redox Potential (mv) Combined Bio and Chemical Reduction Redox Potential Comparison Treatment Time (days) Control ABC ABC+ 22

23 ABC+ Injection Wrentham, MA 5,000 square foot area and a 15 foot thickness Dense material with gravel, which required pre-clearing top 5 feet with auger 5,400 lbs of ABC+ 18 injection points with 5 depth intervals November 2009: PCE = 1,300 ppb and TCE = 93,000 ppb May 2010: PCE = ND < 50 ppb and TCE = ND < 50 ppb Dissolved gases detected and cis-1,2-dce (3,300 ppb) and VC (910 ppb) spiked in May Cis-1,2-DEC and VC reduced in November 2010 to 670 ppb and 430 ppb.

24 Technical Advantages of Sulfate Exists naturally in most groundwater High solubility in comparison to other electron acceptors Easily applied as an aqueous solution Proper application of sulfate enhanced biodegradation will result in no adverse health effects Results are surprisingly rapid 24

25 Sulfate Reduction Case Study Site Background Former gasoline service station with two confirmed releases in 1992 and 2001 Historical remedial efforts with limited success included groundwater pump and treat and monitored natural attenuation Geology consists of fine to medium sand with groundwater present about 10 feet bgs Pilot study was not intended to be a full scale site remediation

26 Jackson, Michigan October 3, GW Flow 1st Qtr 3rd Qtr Sulfate Depleted In core of plume Sulfate East West North BTEX Plume BTEX Baseline Conditions Sulfate is depleted in core Sulfate background is > 50 ppm Max. BTEX is >10,000 ppb 26

27 Jackson, Michigan January 16, 2007 Sulfate Sulfate Increasing BTEX BTEX Shrinking 3 months after initial application Sulfate still elevated in core of plume BTEX >5,000 ppb is shrinking 27

28 Metals Treatment 1. Lead treatment with phosphate buffer. 2. Arsenic/lead treatment with phosphate, calcium buffer and hydrogen peroxide. 3. Hexavalent chromium treatment with ferrous chloride and hydrated lime. 4. Bench Scale Study 5. Majority of project are to assist dig and haul.

29 Heated Water/Steam & Recovery Site in Lawrence, MA; Estimated 500 gallons of No. 6 Oil; Injected heated water into subsurface to create steam; Project was completed in 8 days; Approximately 700 gallons of product was recovered in 6 weeks; No measurable product; and Heated water can be used as an activator.

30 Delivery Capabilities Proprietary injection tools that are integrated with Geoprobe. Permanent injection points (PVC riser and screen). Injection of gasses, liquids and solids in largely varying geological environments - pressures from 10 to 2000 psi (Hydraulic Fracturing). Excavations/Trenches. In Situ Soil Blending for shallow soil (<25 bgs.). 30

31 Why Injection Isn t for Amateurs 31

32 Pump and Treat Gone Bad 32

33 Hydraulic Fracturing Injection of water, solution or slurry at pressure that exceeds the lithostatic pressure and cohesive strength of the formation. Results in short-term enhancement of soil permeability. Increases radius-of-influence and injection rate. 33

34 Hydraulic Fracturing Concept GROUT HEAD - ATTACHES TO GEOPROBE RODS " NYLOBRADE FLEXIBLE PVC HOSE PUMP GEOPROBE RIG GEOPROBE RODS GROUND SURFACE UNFRACTURED SOIL SEAL AROUND GEOPROBE RODS WITH BENTONITE AS RODS ARE PUSHED. SEE DETAIL "A" FRACTURED ZONES BEFORE FRACTURE (Diffusion Controlled) AFTER FRACTURE (Connection & Diffusion Controlled) DETAIL "A" VAPOR MOVEMENT IN SOIL MICROSTRUCTURE

35 Pressure Time History Fracture Maintenance

36 ABC+ Injection Equipment 36

37 In Situ Soil Blending Efficient and uniform delivery of remediation amendments Production rates comparable to dig, haul and backfill No long term liability associated with disposal Costs that can be 2 to 10 times less expensive than dig and haul, depending upon the extent of contamination No RCRA TSD permits are required Can treat a wide range of compounds, such as chlorinated solvents, pesticides, PAHs, etc 37

38 In Situ Soil Blending The Beginning 38

39 In Situ Soil Blending - Improved 39

40 Improvements in Blender Weight reduced by ~50% which reduces transportation costs by factor of two ($5-6 per mile now) Horsepower approximately doubled Independent acting dual motors in custom designed mixing head Torque load sensing on both sides of head so rotation speed automatically adjusts prevents deadheading Base is common excavator so parts readily available 40

41 In Situ Soil Blending Cambridge, MA Dichloroethane (DCA) Contamination 41

42 Post In Situ Soil Blending 42

43 USEPA Site Rhode Island 43

44 Treatment Area 44

45 Blending Activity Day 1 Top Photo A view of the excavation prior to blending activity Bottom Photo A view of the application of the first 1K pounds of KMnO 4 45

46 Blending Activity Day 1 (Continued) Top Photo A view of the initial mixing with an excavator. Bottom Photo A view of the soil blending thoroughly mixing the KMnO 4 with the contaminated soil. 46

47 Day 1 Area Completed 2,000 pounds of KMnO 4 blended with ~ 300 cy of contaminated soil (Area shaded in purple). KMnO 4 not observed in down gradient monitoring wells. 47

48 Day 5 Area Completed 7,000 pounds of KMnO 4 blended with ~ 1,500 cy of contaminated soil (Area shaded in purple). Approximately 8,500 gallons of water was used to blend the KMnO 4 with the soil. KMnO 4 observed in 3 down gradient monitoring wells ( ). 48

49 Day 7 Soil Blending Completed 10,000 pounds of KMnO 4 blended with ~ 2,100 cy of contaminated soil (Area shaded in purple). Approximately 10,500 gallons of water was used to blend the KMnO 4 with the soil. KMnO 4 observed in 4 down gradient monitoring wells ( ). 49

50 Day 12 Post Blending Monitoring KMnO 4 observed in 7 monitoring wells ( ). 50

51 In Situ Remediation Issues Underestimated contaminant mass; Unknown underground structures; Poorly marked utilities; Daylighting; Back Pressure; Surface grade; Aboveground obstructions; and Poorly identified geology

52 The End In Situ Remediation is 1 of many tools; Injection is not the only application technique; Know your site; Work with your In-Situ contractor; Understand the function of the chemical; and For more information: 52