Regenesis

1. Is the reaction of the COCs and product exothermic?
Yes, but the rate of reaction and thus the heat released is controlled by the reaction conditions, No significant chemically induced temperature or pressure has been detected at a RegenOx™ application site.
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2. How does RegenOx reaction not produce significant heat, while still maintaining a high reaction rate?
The active ingredient for RegenOx™ is hydrogen peroxide which does not need to be above 3% for efficient reaction kinetics. At this concentration, the heat production in minimal.
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3. The direct oxidation equation in your literature indicates reaction products include 4 NaCl and 2H₂CO₃. Therefore, will post-injection ground water monitoring show a significant increase in alkalinity and sodium and chloride ions?
The actual effect in alkalinity, sodium, and chloride would be dependent on site specific characteristics. However, typically the amount of sodium added to the subsurfaces is initially less than 300 ppm.
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4. Which is better for CVOCs, PCE, TCE remediation: RegenOx or HRC?
It depends on the concentration and project specific goals, but generally RegenOx™ is better in source zones above 10 ppm and HRC® is better in diffuse plume areas below 1 ppm.
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5. Do you always need a trial/bench soil and/or groundwater sample prior to treatment?
No, in fact a small pilot in the field can be done for a similar cost and can give you more information.
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6. What is the viscosity of the RegenOx mix? Does it inject easily?
RegenOx™ as a 8% solution has the viscosity of water and is easily injected.
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7. What ppm range would you suggest using ORC versus RegenOx?
ORC is usually for the ppb levels in the diffused plume and RegenOx is for the ppm levels in the source area.
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8. Are there standardized methods to measure soil oxidant demand, natural oxidant demand, and total oxidant demand?
Yes, currently we work with two labs that have helped to develop the protocol and can do the analyses for $300/sample.
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9. How do you calculate the stoichiometric demand?
Stoichiometry is calculated according to the following overall equation: 1*X + A*H₂O₂ + B*NaOH ^{^} C*CO₂ + D*NaCl + E*H₂O Appendix A in the RegenOx™ manual shows the calculation for over 40 different COCs.
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10. How much water do you mix into Part A and Part B?
Typically, RegenOx™ is injected as a 3% w/w solution. So, 30 pounds of Part A & B each are added to 116 gallons of water.
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11. Why is the activator mixed for 5 minutes?
The activator is a concentrated, colloid suspension of silica and iron and much of the silica settles out during storage and transportation. If it is not mixed much of the silica sticks to the bottom of the pail.
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12. By the way, I am assuming permanent injection points have to be installed.
No, usually direct push injection points are used because this method usually allow for great control of the vertical and horizontal distribution of the RegenOx™. However, in heavy contaminated source areas where multiple injection events are needed, permanent injection point can be used and are more cost effective.
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13. For the 2nd injection, injection points are different from the 1st one. Will it be more expensive not using the 1st injection points?
Yes, but the increase in effectiveness because of the better distribution of the RegenOx™, counterbalances these costs.
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14. What about pushing away the contamination through the injections?
If displacement of the contaminant is a concern, we design an injection scheme that starts on the outside of the source area and works towards the center of the plume mass.
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15. What is a typical half-life of RegenOx in soil?
Five to 20 days depending on the amount of contaminant and the TOD.
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16. So what is the advantage of RegenOx compared to p+t with respect to rebound?
RegenOx™ has no O&M costs and is more effective in permeating the microporous/diffusion limited contaminants. So, rebound levels will be lower.
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17. What is the effective pH range?
RegenOx™ is most effective in the pH 9 to 11 range, but no pH adjustment is needed. It is functional from pH 7-12.
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18. Is UIC permit required? Has there been a general acceptance of this by the state UIC programs, similar to ORC/HRC? Send me the answer by e-mail as I am leaving the seminar.
UIC permitting is a state-by-state requirements. If a UIC permit is required for HRC or ORC, then it will be needed for RegenOx™. The UIC permitting process should not be any more difficult than for HRC or ORC. RegenOx™ has already been used in several states that require UIC permits.
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19. How substantial are the vapors given off during the oxidation of soils within a building especially where applying to the surface within a basement.
The amount of vapors released by the chemical process can be calculated from the stoichiometry, lithology and physical parameters (depth). Because RegenOx™ does not generate significant heat or pressure, treating with RegenOx™ will not add to the vapor generation via physical transport phenomena.
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20. How calculate a rough initial estimate of injection point spacing?
5-10 in clay and 10 to 20 ft in sand.
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21. Have you had approval for sites in New Jersey and New York?
Yes, We have had several applications in NY. Not in NJ; however, many applications for RegenOx™ injections are being concerned by NJDEP.
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22. Since there is not a significant exothermic reaction, is it acceptable to inject this product in close proximity to pvc cased monitoring wells? Also, have you seen any issues with clogging pore spaces in the well sandpacks?
Yes, RegenOx™ can be applied in Pvc cased wells and around infrastructure. However, if applied at too high a concentration and/or temperature and not flushed out of the sandpack, you can clog the well.
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23. What is the advantage to use Regen ox then just inject low concentration of hydrogen peroxide <10%
RegenOx™ oxidation system is more efficient than Fenton's type reactions, and is effective at lower oxidant concentrations.
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24. In a sandy aquifer, can you overcome close injection spacing by injecting more RegenOx soln (e.g., 120 gallons @ 8%)
Yes, injection designs in sandy aquifers are typically few points, further apart, and higher volumes.
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25. Is RegenOx effective for chlorinated ethanes (111-TCA)?
Yes, We have bench-scale studies that have determined the typical kinetics with various chlorin.
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26. Can it be effective on compounds like PCBs and PAHs?
Yes.
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27. Is RegenOx applicable to MTBE? Since MTBE has a high solubility, how could RegenOx react with MTBE, the net efficiency?
RegenOx™ very effectively degrades MTBE. The high solubility of MTBE does facilitate this efficiency.
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28. For chlorinated solvents (PCE/TCE), are there ant "rules of thumb" (e.g. a concentration range in soil or groundwater) for when you are better off using HRC instead of RegenOx?
The "Rule of Thumb" would be use RegenOx™ in source area with PPM concentrations, and HRc in diffuse plumes with concentrations in the PPB range.
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29. Does it work on PCB contaminated soils and groundwater?
Yes, we are currently doing bench-scale studies to determine the kinetics.
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30. Fenton's is typically most effective in acidic environments. Is the same true for RegenOx?
No, RegenOx™ is a base-catalyzed free radical generating system.
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31. What successes have you had on Gasoline range TPH and BTEX sites in groundwater?
We have several successful sites with TPH and BTEX.
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32. What sort of subsurface/contaminant conditions would the NJDEP be looking for to approve application of RegenOx and what sort of monitoring requirements following application?
As long as your injection program does not exceed 180 day, RegenOx injections can go through the expedited, "Permit-by-Rule" process in NJ.
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33. We were curious about your need to analyze for hex chrome during the monitoring program.
Typically an aquifer is anoxic and chrome (native or manmade) will be in the Cr+3 state which is less soluble. Adding an oxidant like RegenOx™ to the aquifer can temporarily change the chrome to the Cr+6 (chromate) which is more soluble. Typically, this is only observed in the treatment area, and the chromate usually oxidizes organics or inorganics, reverts to the Cr+3 state and falls out of solution. Sential wells outside of the treatment zone should be monitored to confirm this reaction.
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34. Has Regenox been used for treatment of 1,4-dioxane in groundwater in-situ.
Currently, we do not have a case study with 1,4-dioxane, but theoretically, it is degradable by the RegenOx™ oxidation system.
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35. Can you produce chloroform by oxidation of soil organic matter with RegenOx?
Chloroform is mostly oxidized. Chloroform formation through oxidation of soil organic matter is unlikely, and is impossible if there is no chlorine in the system. Chloroform is a disinfection byproduct formed through the oxidation of organic matter in water by using relatively high concentrations of chlorine as the oxidant.
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36. What is the purpose of testing hex chrome in monitoring plan?
See Answer #33.
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37. Is the performance monitoring plan available on-line or for purchase?
Just e-mail us with your request and we will send it to you.
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38. What is the cost of RegenOx?
$1.90 to $2.45/ pound depending on the amounts.
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39. How receptive or not receptive has the state of CA been about this technology?
We have several injections in CA. There are 129 different regulatory bodies in CA so complete acceptance is a little down the road. Please contact us with the names of the exact agencies that you are dealing with and we will let you know if we have gotten acceptance with them yet or not.
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40. You reference injection spacing in several slides - vertical or horizontal?
Injection space horizontally is usually 5 to 15 feet. Vertically, we recommend bottom up injecting through a geoprobe rod, injecting at 1 ft intervals.
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41. Given the choice, is ex-situ vadose zone treatment recommended over in-situ treatment?
On a technical basis, ex-situ treatment is much more likely to be successful than in-situ treatment because you have more control on contacting the oxidant with the contaminant. However, on a overall technical and economic-basis in-situ mixing application may be better.
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42. Can I use this in conjunction with a ZVI application?
The chemistry is not capatible concurrently because RegenOx™ is oxidative and ZVI is reductive. However, sequentially (before or after) they could work.
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43. Is this product capable of treating low levels (e.g. benzene @ ~100 ppb) to a criteria of 1 ppb?
Yes, technically, but it may not be the most economical way to remediate to low levels.
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44. For low level CVOCs (<1ppm to 10 ppb) would HRC or RegenOx be recommended?
It depends on the project objectives (i.e., need for closure in <6 months). In general, enhanced in situ bio has been shown to be a cost-effective remedy for most low level CVOCs sites.
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45. Does RegenOx degrade organic chlorine pesticides?
Yes, theoretically it should be effective on chloro-organic pesticides.
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46. How effective is this technology compared to injecting fenton's reaction, Oxygen, ozone or KMNO4?
RegenOx™ compares well against other oxidants for effective degradation. How well would depend on site conditions.
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47. Will the RegenOx generate bromate?
Bromine has a large range of oxidation states from -1 to +5. So it depends on the starting material.
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48. Can existing 4 inch monitoring wells be used (these were installed with air rotary)?
Yes, but it probably is not a valid monitoring point after the injections.
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49. Can we use the monitoring wells as injection points?
Yes, but it probably is not a valid monitoring point after the injections.
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50. Another question, would you suggest if RegenOx works for ccl4?
Carbon Tetrachloride is completely oxidized, so in theory it cannot be further oxidized by an oxidative process. However, carbon tet is susceptible to chemical reduction and has been shown to be degraded in modified Fenton systems. The mechanism of CCl4 degradation is suspected to be the superoxide radical, a reductant (Watts 2004). RegenOx produces superoxide radicals, so in theory, should be able to degrade carbon tetrachloride. This could be proven through bench testing.
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