REGENESIS "Oxygen Release Compound"

Here's some "bumph" (as the Brits say) from their web site. Not intended as an endorsement, although I understand the product has performed quite well at many field sites.

1. How can I learn more about ORC?

We have a complete set of Technical Bulletins available to you. These will help you understand the technology and its application to your particular site. Also available are Product brochures, price lists and peer reviewed journal articles.

For more information or help in designing your specific application please contact the REGENESIS manager closest to you or call our corporate office technical support at 949-366-8000.

2. How long will ORC release oxygen into a contaminated aquifer?

ORC will begin releasing oxygen upon contact with moisture. The total release period will last from three months to one year, however, this is a site specific issue that is primarily dependent on contaminant load and groundwater velocity. Field experience has indicated that at most hydrocarbon contaminated groundwater sites ORC continues to release oxygen for a period of at least 6 months' time.

3. How much oxygen will ORC provide?

ORC will release a full 10% of its weight as dissolved biologically available oxygen.

4. What concentrations of dissolved oxygen can I expected to see at a site after ORC application?

Unlike air sparging which uses atmospheric air, ORC provides pure oxygen. Thus, the concentration of oxygen from ORC can build up in groundwater to very high concentrations (up to 45ppm or so) before leaving solution in the form of a bubble. This gives ORC technology a tremendous advantage over air sparging in that the high concentrations of oxygen dramatically increase the rate of oxygen diffusion through the subsurface. Thus, ORC has the potential to impact a much greater area around an application point by simple diffusion than can be expected by applying atmospheric air.

It should be recognized however that dissolved oxygen concentrations do not always have the opportunity to build up in the groundwater. If ORC is applied into contaminated groundwater there exists a biological oxygen demand that is using the oxygen -- this is the effect you are trying to achieve where the indigenous microbes are aerobically degrading the pollutant. If the contaminant concentration is actively being reduced, the oxygen is being consumed and therefore may not build up to high dissolved levels. Once contamination in the area around the application point is degraded, the biological oxygen demand in this area is reduced and one can then expect to see a buildup of dissolved oxygen.

5. Can ORC be harmful to the aquifer?

ORC is a non-toxic compound with no potential adverse effects to the aquifer. The by-products of ORC''s reaction with water are oxygen and ordinary magnesium hydroxide, which is virtually insoluble. Thus, ORC liberates only oxygen into the aquifer. The magnesium hydroxide is insoluble and remains as an inert faction of the soil or in the application of filter socks, the magnesium hydroxide is contained within the cloth and is removed from the well. It should be noted that magnesium peroxide and magnesium hydroxide are safe for human consumption as they are both used as anti-acids in common drug store products.

6. Does ORC elevate the pH?

Moderate pH levels are maintained when ORC is used in bioremediation. The pH of magnesium peroxide is 8.5. After it is hydrated and begins to form magnesium hydroxide the pH rises to 10. However, due to the insoluble nature of ORC (the solubility factor is 1.8 x 10-11) and the end product magnesium hydroxide, any pH increase in the subsurface remains highly localized. Thus, a very short distance from the ORC application the pH will be at background levels.

7. Will ORC foul the aquifer?

No. The use of ORC combats the problem of biofouling by generating a highly localized, elevated pH. Hence, microbial growth is inhibited in the immediate area of the application. Regenesis has never received notice of ORC fouling in-situ conditions within an aquifer such as a noticeable reduction in hydraulic conductivity, etc.

Iron fouling is minimized because of the slow, gentle release of oxygen which diffuses out into the aquifer. In fact, ORC has been used in aquifers with elevated iron when air sparging was not possible because of high levels of iron hydroxide precipitated in the vicinity of the sparge points.

8. What is the radius of influence?

The movement of oxygen from an ORC particle is governed by the laws of mass transport. The commonly used advection-dispersion equations, derived from these laws are used to understand the phenomenon.

The principal factor governing the transport of oxygen is groundwater advection. If a project site has significant groundwater flow, the radius of oxygen movement from an ORC application point will be distorted in the down gradient direction. A very fast moving aquifer will result in a narrow band of oxygen moving downgradient with very little lateral spreading of the oxygen.

In the event that there is very little to no groundwater flow at a site, the force of diffusion will dominate the oxygen transport process. In this case, the outward movement of the oxygen is more radial in geometry and is driven primarily by oxygen concentration gradient. Thus in a low flow situation such as a low permeability aquifer material, oxygen being released from the ORC will move outward into the polluted groundwater from an area of high concentration near the ORC particle to an area of low concentration in the polluted aquifer matrix.

9. What are the advantages to using ORC as opposed to other remediation options?

When considering alternatives for remediation of a dissolved phase contaminant plume, ORC is generally the most cost effective treatment option. Due to the accelerating effect that oxygen has on in situ biodegradation processes, ORC is often used to expedite, and therefore reduce the cost of natural attenuation approaches to site remediation. The process of using ORC to reduce the cost of natural attenuation and expedite site closure has been termed ""Accelerated Natural Attenuation"" by the environmental engineering industry.

Because ORC is a passive treatment technology, O&M costs are substantially reduced as compared with other mechanical remediation technologies such as pump and treat or air sparging with SVE.

10. Is ORC useful in unsaturated soil applications?

Sometimes. When considering in situ soil treatment ORC may be cost effective, based upon the concentration of contaminant to be degraded, and the ability to transport the ORC particles and/or oxygen to the specific subsurface area impacted. In highly impacted soils, or soils of very low hydraulic conductivity ORC may not be cost effective. Having said this, ORC has been shown to be very cost effective as several sites where low concentrations of hydrocarbons were degraded in high permeability unsaturated soils.

Another good application of ORC is where the product is employed to keep soil clean after is has been put back in an excavated pit with a rising groundwater table. In this type of application, ORC powder is mixed into the bottom of the pit prior to backfilling. Then, when the contaminated groundwater rises, the ORC''s oxygen is released and aerobic bioremediation will ensues, degrading the encroaching hydrocarbon. Other soil applications include remote, excavated biopiles or contaminated soils that cannot be mechanically aerated for physical or environmental reasons.

11. Can ORC be used to remediate chlorinated hydrocarbons?

Yes, if the compound is aerobically degradable. The most visible of these applications is for vinyl chloride treatment. Vinyl chloride is a highly carcinogenic degradation product of perchloroethene (PCE) and trichloroethene (TCE), which is often associated with dry cleaning operations and landfills. Unlike its more highly chlorinated parent compounds which require treatment by anaerobic dechlorination, the vinyl chloride is aerobically degradable, and thus is rapidly degraded by indigenous microbes in the presence of ORC. If you are interested in the treatment of more high chlorinated compounds such as PCE and TCE, we encourage you to consider the use of Hydrogen Release Compound (HRC™) which was developed specifically for he treatment of these compounds.

12. Have regulatory agencies approved the use of ORC?

Yes. ORC has been approved for use in all 50 states of the US. In addition it has been used in many other countries including Canada, UK, Germany, Poland, Netherlands, Denmark, France, Italy, Japan, Korea and Australia.

13. Are there any disposal issues with the spent ORC?

No. The ORC powder if injected into the aquifer for plume treatment remains in-place after treatment, becoming an innocuous part of the soil matrix. In the Filter Sock form, the socks are not considered a hazardous waste unless perhaps they have been allowed to absorb large amounts of phase separated chemicals. Thus, if used properly the socks can simply be disposed of as non-hazardous waste

14. What references are available on ORC''s effectiveness?

Since its introduction in 1995, well over one hundred technical papers have been published on the effectiveness of ORC. A partial listing of publication as well as several complete peer reviewed articles on ORC are available for your review and download.