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Peroxygen Talk

July 2008

Surfactant Enhanced In Situ Chemical Oxidation

In this month’s Peroxygen Talk, Dr. John Collins, President and CEO of VeruTEK Technologies, and Dr. George Hoag, Senior Vice President for Research and Development at VeruTEK, discuss the use of to enhance in situ chemical oxidation of contaminants in NAPLs and absorbed phases. Dr. Collins earned a PhD in Soil Science from UC – Riverside. He has spent the last 15 years consulting to the Department ofDefense/Energy/EPA and Fortune 500 companies on environmental risk, remediation, insurance cost recovery and liability. Dr. Collins is a well-known proponent of green technologies in solving the worldwide legacy of industrial contamination. Dr. Hoag received a PhD in Environmental Engineering from University of Connecticut. In addition, he founded and directed the Environmental Research Institute at the University of Connecticut until 2002. He has over 200 peer- reviewed scientific papers, 4 patents and is one of the founding fathers of In Situ Chemical Oxidation (ISCO), Soil Vapor Extraction and other environmental remediation methods. In 2005, Drs. Hoag and Collins founded VeruTEK Technologies. Please find their article on -enhanced ISCO in the attachment below. Surfactant Enhanced In Situ Chemical Oxidation (S-ISCOTM) Treatment of Non Aqueous Phase Liquids John Collins, Ph.D. and George Hoag, Ph.D. VeruTEK Technologies, Inc. 65 West Dudley Town Road, Bloomfield, CT 06002 www.verutek.com

INTRODUCTION

According to USEPA (2004), Cleaning up the Nation’s Waste Sites, an estimated 294,000 contaminated sites will need to be cleaned up. The estimated cost to clean up these sites is about $209 billion.1 Many of these sites contain Non Aqueous Phase Liquids (NAPLs), which VeruTEK’s technology specifically remedies. NAPL may be dense or light with respect to the density of , approximately 1.0 gm/ml at 25º deg. C. Those liquids immiscible with water having densities greater than the density of water are dense non aqueous phase liquids (DNAPL). Those liquids having densities less than water are light non aqueous phase liquids (LNAPL). The basic reason that NAPLs persist at sites is the result of the highly hydrophobic properties of the chemicals that make up NAPLs. Aqueous of many NAPLs are quite low and include such compounds as benzene ~ 1,791 mg/L, 1,1,1-trichloroethane ~ 1,495 mg/L, tetrachloroethene ~ 150 mg/L, naphthalene ~ 31.7 mg/L, 1,3,5-trichlorobenzene, ~ 6.01, dieldrin ~ 0.17 mg/L, benzo[a]pyrene ~ 0.003 mg/L.2,3 When NAPLs are made up of many chemicals, the aqueous of non polar organic compounds can greatly decrease, based on their in the NAPL and activity coefficient, as described by Raoult’s Law.4 Even though NAPLs have been released to the subsurface at some sites more than 100 years ago, there remains large quantities of these materials present in the subsurface today. Many NAPL sites exist in the United States alone. It is estimated that 37 percent of all USEPA National Priority List (NPL) Sites have DNAPLs present. For the dry cleaning industry alone, USEPA estimates that there are more than 100,000 active and inactive sites. Overall, USEPA estimated as of 2005 that there were approximately 294,000 sites with DNAPL and 447,000 petroleum-related sites in the U.S. alone.

THE S-ISCOTM PROCESS

Surfactant-Enhanced In-Situ Chemical Oxidation (S-ISCO™) is a new field verified Coelution Technology™ capable of reducing the amount of source NAPL in soils and reducing the flux of groundwater constituents associated with these sites. S-ISCO™ remediates NAPLs and contaminant species that are strongly sorbed to soil and sediment. It is well known that In Situ Chemical Oxidation (ISCO) reactions predominantly take place in the aqueous phase in the subsurface, and have limited impact on contaminants bound to soil and in the NAPL phase. In a recent study published by the State of Colorado, Division of Oil and Public Safety in 2007, assessment of ISCO application at 20 sites with some degree of NAPL present was investigated. Of the 20 sites where ISCO was implemented 15 sites resulted in lack of success and 3 additional sites had uncertain success. 5 Interactions with contaminants bound to soil or in the NAPL phase are not effectively addressed using ISCO treatment alone, but are addressed using the S-ISCO™ process. Other than associated with sampling, the S-ISCOTM process does not generate any 1 wastes on site as compared to excavation, thermal or stabilization processes. Additionally, the carbon-greenhouse gas footprint of this new process is dramatically lower than with energy and material intensive processes, such as excavation, thermal and stabilization-containment remedies. S-ISCO™ is a Green Coelution TechnologyTM developed by VeruTEK Technologies, Inc. (VeruTEK™) which includes plant-based ingredients. S-ISCO™ uses a patent-pending surfactant-cosolvent , VeruSOL™, which enables aqueous phase oxidant reactions to destroy solubilized NAPLs. VeruSOL™ is a biodegradable, U.S. FDA Generally Recognized as Safe (GRAS) plant oil-based cosolvent and surfactant system (i.e., coconut oil, castor oil, and citrus extracts). Once NAPL constituents are dissolved in the aqueous phase using VeruSOL™, a choice of a variety of chemical oxidation technologies can be effectively used to destroy the contaminants and reduce contamination. Because the rate of partitioning of contaminants into the aqueous phase determines the overall rate of reaction, as the of VeruSOLTM is increased, the partitioning and subsequent rate of chemical oxidation is increased. Therefore, using VeruSOL™ in S-ISCO™ increases the rate at which contaminants transfer to the aqueous phase, resulting in faster and more complete NAPL and soil decontamination utilizing oxidation reactions. This is significant over other methods of remediation such as ISCO. Solubilization of NAPL constituents with continued immobilization of NAPL in the soil pore space are controlled using S-ISCOTM which is key to this process. The addition of VeruSOL™ increases DNAPL and adsorbed compound solubility in water between one to three orders of magnitude without physical mobilization of the NAPL. The scientific merit of this discovery revolves around VeruTEK's ability to match the fate, transport and reactions of the green cosolvents and surfactants with the activity of oxidants, particularly free-radical based chemical oxidants. S-ISCOTM involves coeluting both the cosolvent- surfactant mixture with the oxidant enabling concurrent dissolution and oxidation. The inherent properties of plant-oil based surfactants to resist immediate chemical oxidation is key to VeruTEK's ability to simultaneously transport the surfactant and oxidants through the subsurface and target NAPL contaminated zones. The injected VeruSOL™ surfactants have a lipophilic end that is attracted to non polar constituents in NAPL. The other end is hydrophilic and is attracted to the water. The surfactant creates a microemulsion of the NAPL in the oxidant . A microemulsion is a solution composed of oil, water and surfactant and/or cosolvent or cosurfactant. Nanometer-sized form with the immiscible liquid as dispersed in the aqueous phase with surfactant at the interface. There are oil-in-water and water-in-oil microemulsion systems. An oil-in-water microemulsion is a Winsor Type I . VeruTEK’s green surfactant/cosolvent mixture achievesWinsor Type I solubilization, where the NAPL is solubilized as a single-phase microemulsion and dissolution of constituents occur without NAPL mobilization. Logically these systems have high solubilization while requiring low amounts of chemical additives. Winsor Type I microemulsification will solubilize less NAPL than in either Winsor Type II or III systems, which allows for control of the S-ISCO™ process. VeruTEK’s patent pending S-ISCOTM process avoids Winsor Type II systems, that is, water-in-oil with oil as the continuous phase and water inside the , which results in mobilization of the NAPL, typical of Surfactant Enhanced Aquifer Remediation (SEAR) flushing product recovery processes. Winsor Type III microemulsions are formed between the two types where the systems changes from hydrophilic to lipophilic. In this mid-phase the

2 interfacial tension drops extremely low. Winsor Type III promote NAPL mobilization and require a delicate balance of various parameters, typically difficult to achieve for subsurface applications. Winsor Type III Emulsions are not formed as part of the S-SICOTM process. The field of surfactant chemistry is well developed and excellent reviews and papers exist that describe Winsor systems and interactions of surfactants and surfactant-cosolvent mixtures with NAPLs of environmental significance. 6,7 Solubilization of NAPLs using Winsor Type I systems have also been well documented and relationships between solubility enhancement and octanol/water partition coefficients8, relationships between several molar solubilization ratios (MSRs) and -lipophile balance (HLB) for several single component NAPLs for a particular non ionic surfactant system.9 LABORATORY TESTING

An example of a Winsor Type I system made with VeruTEK’s VeruSOL-3TM cosolvent- surfactant system is shown in Figure 1. A Manufactured Gas Plant (MGP) DNAPL sample was obtained from a site. In comparison, a laboratory simulated sample using a trichloroethylene (TCE) DNAPL is shown in Figure 2. It is clear from these two figures that a single phase Winsor Type I system is formed in these two experimental systems. Using a complex chlorinated DNAPL obtained from a field site, solubility enhanced factors for the major compounds in the DNAPL mixture were related to the octanol-water in a method similar to that of Jafvert (1991).7 It can be readily seen that the solubility enhancement factors for the three major compounds carbon tetrachloride (log Kow = 2.83), tetrachloroethylene (log Kow = 3.40) and hexachlorobutadiene (log Kow = 4.90) follow linear relationships at a given VeruSOL-3TM concentration and increasing slopes with increasing of the VeruSOL-3TM mixture as observed in Figure 3. Based on the above relationships, controlled dissolution of NAPL mixtures using VeruSOL-3™ can be readily developed using both experimental and theoretical bases. The ability of S-ISCOTM process to destroy a complex chlorinated DNAPL mixture used in the above solubilization tests is demonstrated in the following example, as shown in Figure 4. Samples of the dissolved DNAPL microemulsions were oxidized with alkaline persulfate at concentration 200 g/L and at a pH>11, adjusted with sodium hydroxide (NaOH). On the left side of Figure 4, results from the dissolution tests are summarized for three of the VeruSOL-3™ doses used along with a control test (only site groundwater and DNAPL) for Total Volatile Organic Compounds (VOCs) and Total Polycyclic Aromatic Hydrocarbons (PAHs). On the right side of Figure 4, results of the oxidation tests are summarized. After only a 14 day reaction period percent destructions of the 0.4 g/L and 4.2 g/L VeruSOL-3TM dosed DNAPL were greater than 99 percent for VOCs and SVOCs. For the 83.3 g/L VeruSOL-3TM dose, the percent reduction was approximately 94 percent for VOCs and 75 percent for SVOCs and only required a longer reaction period to achieve greater than 99 percent compound destruction. When applied in the field, the residence time for the S-ISCOTM chemicals at sites will be on the order of several months, which allows ample time for reactions to go to completion.

Subsequent soil column testing was conducted on highly contaminated soils from the site that were also spiked with Suidan IV red-dyed DNAPL. A photographic comparison of a typical ISCO process (alkaline persulfate with 50 g/L sodium persulfate at a pH > 10.5) with the S- ISCOTM process (alkaline persulfate with 50 g/L sodium persulfate at a pH > 10.5 and 5 g/L VeruSOL-3TM) is shown in Figure 5. After only 14 days of treatment, the S-ISCOTM process 3 had a 97 percent reduction in Total VOC and SVOC concentrations in the column effluent in comparison to the control column. The S-SISCOTM column, achieved nearly 99.99+% removal (57% degraded + 43% eluted-out) of the Total VOCs and SVOCs in the tests. Visually, the difference between the amounts of DNAPL left in the columns is dramatic.

Additional soil column test results demonstrate the ability of the S-ISCOTM process to remediate soils contaminated with MGP residuals. The results of three soil column tests contaminated with various concentrations of MGP residuals (~5,000 mg/kg to 50,000 mg/kg) are shown in Figure 6. To simulate dispersed MGP DNAPL in soils, each column was contaminated with MGP DNAPL by dissolving either 1 g or 5 g of the DNAPL in hexane, then saturating the columns with the mixture followed by evaporation of the hexane, leaving the MGP DNAPL on the soil. After 28 days of contact with the S-ISCOTM chemicals (Fe(II)-EDTA activated persulfate and VeruSOL-3TM) the columns achieved greater than 99.9% removal of the MGP DNAPL, based on TPH analysis of the soils before and after treatment.

FULL-SCALE FIELD TRAIL

Field applications of S-ISCOTM technologies at sites with organic contaminants in either or both of the LNAPL and DNAPL phases or with sorbed phases are dependent on several factors for successful achievement of removal of the NAPL or sorbed phases. These factors can include the following:

1) Effective delivery of injected oxidants, activating , and surfactants or surfactant-cosolvent mixture into the subsurface.

2) Travel of oxidant, activator, and surfactant solutions to the desired treatment interval in the soil.

3) Selection of surfactants or cosolvent-surfactant mixtures and oxidants to ensure coelution of the surfactants or cosolvent-surfactant mixtures and enable subsequent injected oxidants to travel to the desired treatment interval in the soil.

4) Desorption and apparent solubilization of NAPL constituents and residual NAPL phases into the aqueous phase for destruction by the oxidant and radical species.

5) Reactions of oxidant and/or radical species with target mobilized contaminants of concern (COCs).

8) Adequate monitoring of COCs, injected oxidant and activator solutions, essential geochemical parameters and any other environmental media potentially affected by the treatment.

The S-ISCOTM process underwent a large-scale field trial in Long Island, New York in 2006 under review and oversight of the New York State Department of Environmental Conservation (NYSDEC) and an oversight consulting firm. The test site was a 125 years old former manufactured gas plant (MGP) site. Coal tar DNAPL residually saturated soils with oil droplets were evident when examining soils cores obtained from the test site prior to treatment.

4 The field trial test area was 30 ft by 60 ft and with a saturated thickness of approximately 60 feet. The subsurface consisted predominantly of medium to fine, well sorted sands. The Pilot Test operating conditions are given in Table 1. Chemical injection took place at this site for 31 days on a 24 hour – 7 day per week basis.

Groundwater monitoring to document the presence and persistence of the injected chemicals took place continuously at this site. Additionally, groundwater VOC and SVOC concentrations were measured on 5 occasions from 7 monitoring well clusters, including before and after treatment. Soil samples were taken from 54 discrete sampling locations before and after treatment. The soil sampling results averaged by depth interval in the pilot test area prior to treatment for VOCs and SVOCs are illustrated in Figure 7. In comparison, the soil sampling results after treatment, are shown in Figure 8. More than 4,000 kg of medium weight petroleum hydrocarbons were destroyed during the test. Following the completion of the pilot test in June 2006, groundwater samples were taken quarterly from monitoring wells located up gradient and down gradient from the pilot test area. Photologs of soil borings taken within 3 feet of each other before and after the S-ISCO™ treatment illustrate the typical visual change observed when comparing pre-treatment to post-treatment conditions are shown in Figure 9. The results from Quarter 1 and Quarter 2, 2007 reveal that all down gradient monitoring wells had lower VOCs and SVOCs results than the historical mean concentrations from each well. In most cases, the reductions in concentrations were dramatic, even though much of the down gradient zones were beyond the S-SICOTM process treatment zones. The continued monitoring demonstrates that rebound has not occurred. The oversight consultant’s Pilot Test Report conducted in accordance with a NYSDEC work plan evaluating the effectiveness of S-ISCOTM showed that “…complete or near complete remediation…” can be achieved where S-ISCOTM is in contact with MGP impacted soils.

CONCLUSIONS

The S-ISCOTM process, recently developed by VeruTEK, is a profound improvement over prior In Situ Chemical Oxidation processes. Not only does this process enable treatment of NAPLs at a wide variety of contaminated sites that pose risk to the public and the environment, it provides green chemistry solutions (or reaction conditions) as well. The use of U.S. FDA GRAS citrus- based surfactants and plant oil-based surfactants enables effective dissolution and emulsification of NAPLs so that commonly used chemical oxidants can break down toxic organic chemicals. In the case of the field trial example presented in this paper, the persulfate was obtain from FMC Corporation manufactured using a hydroelectric power renewable energy source generated at Niagara Falls.

This new process enables complete in situ treatment at NAPL sites and does not create additional risks to the public or the environment, as with many ex situ-based remedies. Other than associated with sampling, the S-ISCOTM process does not generate any wastes on site as compared to excavation, thermal or stabilization processes. Additionally, the carbon-greenhouse gas footprint of this new process is dramatically lower than with energy and material intensive processes, such as excavation, thermal and stabilization-containment remedies. Effective in situ treatment using this process also minimizes; 1. potential human risk caused by exposure to vapors and contaminated soils, 2. groundwater and NAPLs requiring above ground storage and

5 3. treatment and/or transportation and disposal associated with excavation, thermal and stabilization-containment remedies.

In situ destruction of high NAPL concentrations of in soils, groundwater and sediment represents a significant advancement over previous ISCO technologies alone that only treat compounds in the aqueous phase and are limited in effectiveness, as such. The ability to utilize US FDA Generally Recognized as Safe products represents a major technological breakthrough in the field of in situ remediation and green chemistry. S-ISCO™ benefits outweigh excavation, thermal processes and stabilization-containment remedies with respect to the safety of the community surrounding the remediation site, transportation corridors and treatment/disposal sites.

REFERENCES

1. U.S. Environmental Protection Agency, Office of Solid Waste and Emergency Response. Cleaning Up the Nation's Waste Sites: Markets and Technology Trends. 2004 Edition. EPA 542-R-04-015, September 2004. 2. Howard, P.H. (editor). Handbook of Environmental Fate and Exposure Data for Organic Chemicals. Volumes I (1989), II (1990), III (1991). Lewis Publishers, Michigan. 3. Verschueren, K. Handbook of Environmental Data for Organic Chemicals. 2nd edition, (1983) Van Nostrand Reinhold, Co., New York. 4. Schwarzbach, R.P., Gschwend, P.M., and Imboden, D.M. Environmental . (1993). John Wiley & Sons, New York. 5. The Colorado Department of Labor and Employment Division of Oil and Public Safety. (2007) Petroleum Hydrocarbon Remediation by In-situ Chemical Oxidation at Colorado Sites, June 2007. 6. Winsor, P. A. (1948). Hydrotropy, solubilization, and related emulsification processes, Part I, Transactions of the Faraday Society, 54:376-399. 7. Jafvert, Chad T., Technology Evaluation Report: Surfactants/Cosolvents, Ground-Water Remediation Technologies Analysis Center Report, TE-96-02, December, 1996. 8. Jafvert, Chad T. (1991). Sediment and saturated-soil-associated reactions involving an anionic surfactant (dodecylsulfate). 2. Partitioning of PAH compounds among phases, Environmental Science and Technology. 25:1039-1045. 9. Diallo, M.S., L.M. Abriola, and W.J. Weber. (1994). Solubilization of nonaqueous phase liquid hydrocarbons in micellar solutions of dodecyl ethoxylates. Environmental Science and Technology, 28(11): 1829-1837.

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