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GGeeoo--CClleeaannssee IInntteerrnnaattiioonnaall,, IInncc.. 400 State Route 34, Suite B

Matawan, NJ 07747 (732) 970-6696

www.geocleanse.com

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Geo-Cleanse Experience (States in blue)

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Since 1995, Geo-Cleanse International, Inc. (Geo-Cleanse) has been dedicated exclusively to the design and implementation of in-situ chemical remediation technologies. We have completed well over 150 full-scale remediation programs across the United States, and have been active internationally since 1999, conducting the first in-situ chemical remediation application in Europe. We are a full-service remediation firm, offering a variety of chemical remediation services, including site-specific design and implementation of bench-, pilot-, and full-scale applications. Geo-Cleanse has consistently provided innovative remedial solutions to our diverse client network, and we continue to expand our services to incorporate the advances occurring within the industry. Our extensive field experience, together with independently published results of our work, and our knowledgeable staff of professionals, ensures that Geo-Cleanse continues to be one of the world’s top environmental remediation firms. Our experience includes the design and implementation of the two largest in-situ chemical oxidation (ISCO) projects ever performed, one of which included over 1,200 injection wells and over 3 million gallons of peroxide solution. Geo-Cleanse has been the leader in the in-situ chemical remediation field, completing the first ISCO treatment program to address chlorinated dense non-aqueous phase liquid contamination and manufactured gas plant contamination. We have experience remediating a wide range of contaminants including petroleum hydrocarbons, chlorinated solvents, manufactured gas plant constituents, energetics, chloromethanes, and pesticides.

Office Location: 400 State Route 34, Suite B

Matawan, NJ 07747 Tel. 732.970.6696 Fax 732.970.6697

www.geocleanse.com


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Our Services

In-situ chemical remediation offers an efficient and effective way to eliminate organic contaminants in both saturated and unsaturated environments. The Geo-Cleanse® Process, which patents both the methodology and injection equipment, can be utilized to distribute either catalyzed hydrogen peroxide solutions or other oxidant based reagents (permanganate and sodium persulfate) to the subsurface.

A critical step in ensuring the success of a remedial design is selecting the appropriate chemical oxidant. Geo-Cleanse evaluates each of the oxidant’s strengths and weaknesses as they apply to the site and its relevant conditions, and then chooses the appropriate oxidant or oxidants. Once the oxidant or oxidants have been selected, Geo-Cleanse designs site-specific treatment program for our client.

Treatment programs utilized by Geo-Cleanse are comprised of one or a combination of the following types:

• Bench-Scale Treatability Studies • Pilot-Scale Treatment Programs • Full-Scale Treatment Programs • Pay-for-Performance Treatment Programs

Because our patented injection equipment and methodology are equipped to deliver all types of oxidants and substrates to the subsurface, Geo-Cleanse evaluates each site to determine which oxidant provides the best fit, both chemically and economically.

Geo-Cleanse initially researches the ability of each oxidant to destroy the type of contamination present. For example, at sites containing BTEX compounds, it is well known that permanganate cannot oxidize the benzene ring, thus eliminating permanganate as an oxidant choice

at sites containing BTEX impacts. Next, Geo-Cleanse calculates the number of pounds of contaminant present at the site and corresponding number of pounds of oxidant necessary to destroy that amount of contamination. Using the calculated total amount of oxidant to be delivered, Geo-Cleanse then determines the rate of delivery of the oxidant solution by evaluating the lithologies. Finally, Geo-Cleanse looks at the cost of the oxidant and the timeframe associated with delivery. The oxidant package that is more effective and less expensive than the other is then selected.


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Oxidant Chemistry

Catalyzed Hydrogen Peroxide The chemistry involved with catalyzed hydrogen peroxide (CHP) is based upon Fenton’s reagent. In 1894, H.J.H. Fenton reported that malic acid was rapidly oxidized by hydrogen peroxide in the presence of iron salts. Haber and Weiss (1934) identified the oxidation mechanism resulting from mixtures of hydrogen peroxide and ferrous iron (referred to as Fenton’s reagent) as a hydroxyl free radical (OH·) formed by the reaction: H2O2 + Fe+2 → OH· + OH- + Fe+3

(1)

Where H2O2 is hydrogen peroxide, Fe+2 is ferrous iron, OH· is hydroxyl free radical, OH- is hydroxyl ion, and Fe+3

is ferric iron. CHP chemistry is complex, involving a number of additional reactions producing both oxidants and reductants that contribute to the destruction of the contaminant of concern (e.g., Watts et al., 1999a):

OH· + Fe+2 → OH- + Fe+3

Fe (2)

+3 + H2O2 → H+ + HO2· + Fe+2

Fe (3)

+2 + HO2· → Fe+3 + HO2-

Fe (4)

+3 + HO2· → Fe+2 + O2 + H+

OH· + H (5)

2O2 → H2O + HO2

HO· (6)

2· → H+ + O2·-

(7)

Where HO2· is hydroperoxyl radical, HO2- is hydroperoxyl anion, O2 is molecular oxygen, O2·- is

superoxide radical, H+ is hydronium ion, and H2O is water. Additional reactions occur with organic compounds. The suite of reactions associated with CHP is complex, but very effective at destroying many organic compounds dissolved in groundwater, sorbed to soil, or existing as non-aqueous phase liquids in the subsurface. CHP is generally most efficient under acidic pH conditions (pH <5) because oxidation of iron (from Fe+2 to Fe+3

) by other reactions is minimized, hydrous ferric iron oxides are less likely to precipitate and remove iron from solution, and bicarbonate (which competes with the organic compounds for hydroxyl radicals) is absent. However, an effective (although not chemically optimal) Fenton’s reagent system can be established at a pH >6 (e.g., Watts et al., 1999b; Lindsey and Tarr, 2000).

The hydroxyl free radical is a powerful, non-selective oxidant. Oxidation of an organic compound by hydroxyl free radical is a rapid and exothermic (heat-producing) reaction. Rate constants for reactions of hydroxyl free radical with common environmental pollutants are typically in the range of 108 to 1010 M-1s-1 (e.g., Buxton et al., 1988; Haag and Yao, 1992), and 100% mineralization is generally complete in minutes. Intermediate compounds are primarily naturally occurring carboxylic acids, and the end products of oxidation are primarily carbon dioxide and water. None of the injected reagents pose an environmental hazard. Unconsumed H2O2

naturally degrades to oxygen and water after injection.


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Sodium or Potassium Permanganate Permanganate is supplied as a soluble salt, either as the potassium permanganate (KMnO4) or sodium permanganate (NaMnO4). The two salts differ primarily by solubility; however in aqueous solution both dissolve to release the cation (either Na+ or K+) and the anion (MnO4

-

):

NaMnO4 → Na+ + MnO4-

KMnO (1)

4 → K+ + MnO4-

(2)

The active oxidant for either salt is the permanganate anion (MnO4

-

), which is a strong and persistent oxidant in the subsurface.

The permanganate oxidation pathway for alkenes such as TCE begins with electrophilic attack on the carbon-carbon double bond, producing a cyclic hypomanganate diester as a reaction intermediate. There are two potential oxidation pathways for the diester intermediate, via either hydrolysis to glycol aldehyde or bond cleavage to formaldehyde. Both compounds continue to degrade to carboxylic acids.

Sodium Persulfate Persulfates are strong oxidants that have a wide variety of industrial applications. Dissolution of a persulfate salt such as sodium persulfate (Na2S2O8) in water liberates the persulfate anion (S2O8

-2

) which is an oxidizer:

Na2S2O8 (solid) → 2Na+ + S2O8-2

S (1)

2O8-2 + 2H+ + 2e- → 2HSO4

-

(2)

The persulfate anion has an oxidation potential of 2.1 V. In addition to direct oxidation by the persulfate anion, the persulfate anion can be catalyzed to produce a persulfate radical (SO4•

-

):

S2O8-2 + initiator → SO4•

- + (SO4•- or SO4

-2

) (3)

The persulfate radical is a more powerful oxidizer than the persulfate anion, and has an oxidation potential of 2.6 V. Commonly used activators to catalyze persulfate are heat, hydrogen peroxide, transition metals, and high pH. For economical and technical reasons the most commonly used activators in the environmental industry for ISCO are transition metals and high pH.


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Injection Well Installation

Injection wells can either be temporary or permanent injection points. Geo-Cleanse requires that permanent injection points are installed by direct push or sonic methods by a licensed driller. The

spacing between injection wells is typically a conservatively small spacing appropriate to distribute the reagents across the target treatment zone. Our permanent injection wells are constructed with material this is compatible with the injected reagents and elevated temperatures if CHP is applied. When applying CHP, permanent injection wells, in contrast to temporary (direct push) injection points, is preferred for several reasons:

1. Direct push drill rigs and crews are only mobilized once for well installation. If additional injection phases are necessary, wells can be reoccupied. In contrast, if additional injection is necessary with temporary well points, drilling crews must also be remobilized.

2. Adjacent injection wells provide a dense network of process monitoring locations. These wells allow close monitoring of treatment progress to ensure that appropriate chemical conditions are established, treatment is occurring effectively, and to determine the actual radius of influence. The process monitoring data are critical for daily optimization of the injection to ensure the most efficient treatment program. Process monitoring and optimization are not possible with temporary injection points.

3. Installation is relatively inexpensive. Injection and vent wells are installed using direct push drilling technology and are constructed of CPVC.

4. Geo-Cleanse can establish a larger radius using permanent injection wells in conjunction with our patented equipment. Temporary injection locations, due to the nature of that type of delivery, can generally only distribute reagents a few feet from each location.

5. Multiple injection wells can be treated simultaneously. Geo-Cleanse mobile treatment units can each independently treat between four and 12 injection wells simultaneously.


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Injection Equipment

The Geo-Cleanse® Process utilizes a specialized mobile treatment vehicle and patented injection heads to deliver reagents to the subsurface. The treatment unit includes tanks, pumps, gauges and flow controls to prepare and deliver injection solutions safely and effectively to the injection wells. The mobility of the Geo-Cleanse Process® allows effective remediation with no permanent structures, no need to remove pavement or buildings, no need to close facilities, and no disruption of operations. Geo-Cleanse has small and large rigs, depending on the size of the site. We also have specially designed injection boxes, that we can be used within tighter areas (e.g., inside a building). The view of the injection vehicle shows the control board, which allows the operator to independently control the

flow of reagents and injection pressures to each of the four mixing heads. The mixing heads are specifically designed to control and mix the reagents used during the Geo-Cleanse® Process. The figure to the right shows the general design of an injection head. The specially designed mixing heads are designed with redundant safety features including check valves, pressure gauges and flow control ball valves which are all constructed of material compatible with all of the reagents. The mixing head has a duplicate set of ball valves to control the flow of catalyst, oxidant, and air as a secondary and backup control. The mixing heads are constructed of polypropylene and CPVC for chemical compatibility, and have a pressure relief valve at the base for added safety. The ability to monitor the flow of reagents is present at the control board of the injection vehicle, the control valves of the mixing heads, and the control valves of the reagent storage tanks. The redundant control is established for health and safety reasons. The Geo-Cleanse mobile treatment unit is powered by a 60-kW generator.


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Daily Process Optimization-CHP

CHP requires characteristic pH and iron concentration ranges in order to be most effective, and the nature of a CHP injection allows constant monitoring to ensure the treatment is occurring effectively. Geo-Cleanse conducts routine process monitoring sampling and data analysis each day to ensure that subsurface conditions within an active injection area are optimal for an effective and efficient CHP treatment. These data are evaluated daily to assess the treatment progress and to optimize the injection. This optimization includes an assessment of the catalyst formulation and target injection volumes, to ensure treatment progresses efficiently.

Geo-Cleanse monitors pH, alkalinity, dissolved iron, hydrogen peroxide and chloride concentrations, PID headspace, and temperature taken from groundwater samples obtained daily from the injection and monitoring wells within the treatment area. These field parameters monitor the reaction progress and ensure that appropriate subsurface conditions exist for an efficient reaction. They also assist Geo-Cleanse in proportioning additional reagents into areas onsite where contamination still exists. Monitoring of the offgas concentrations, from the injection and the monitoring wells within

the treatment area, also occurs during injection. These offgas parameters, coupled with the groundwater measurements are effective in determining the progress of a treatment program in the field.


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Case Studies

A few case studies and our most recent newsletters are included as Attachment B. Additional case studies and past newsletters are located on our website. The case studies give an overview of the site conditions and treatment program design. If requested, Geo-Cleanse can provide additional information regarding our past and current projects in the US and abroad.


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Site Data Desired for Project Design

The site information desired for final Geo-Cleanse project design is typically included in a very thorough remedial investigation report. Specifically, we search for the following information: I. General Site Information.

A. Map(s) with buildings, overhead or underground utilities, sample locations, etc. B. Topographic map. C. Site history, especially regarding the plume origin, previous remediation, etc. D. Site hazards and access for drill rig, Geo-Cleanse treatment rig, etc.

II. Soil Data.

A. Detailed lithologic descriptions and geologic cross sections. B. Soil density. C. All soil boring logs from the site. D. All soil analytical data in tabular form. E. Contaminant isopleth maps (by compound and by discrete depth intervals).

III. Groundwater Data.

A. Detailed lithologic descriptions of the aquifer (boring logs). B. Depths of aquiclude/aquitard intervals. C. Depth to groundwater and seasonal variations. D. Hydraulic conductivity. E. Porosity. F. Water quality (pH, alkalinity and iron concentration). G. All groundwater analytical data in tabular form. H. Observations/thickness of free product layers. I. Contaminant isopleth maps (by compound and by aquifer if more than one). J. Groundwater piezometric surface map.

IV. Bedrock Data (if applicable).

A. All groundwater quality data described in Section III. B. Depth to bedrock, and unconsolidated soil data described in Section II. C. Depth to water and seasonal variations. D. Distribution, strike and dip of fracture sets and discrete zones. E. Packer testing results (pump tests, temperature, resistivity, etc.).


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Attachment A References


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References Cited

Buxton, G., Greenstock, C.L., Helman, W.P., and Ross, A.B. 1988. Critical review of rate constants for reactions of hydrated electrons, hydrogen atoms and hydroxyl radicals (·OH/·O-

) in aqueous solutions. Journal of Physical Chemistry Reference Data, v. 17, pp. 513-886.

Haag, W. W. R., Yao, C. C. D. 1992. Rate constants for reaction of hydroxyl radicals with several drinking water contaminants. Environmental Science and Technology, v. 26, pp. 1005-1013.

Haber, F., and Weiss, J. 1934. The catalytic decomposition of hydrogen peroxide by iron salts. Proceedings of the Royal Society of London, Series A, v. 147, pp. 332-351.

Lindsey, M. E., and Tarr, M. A. 2000. Inhibition of hydroxyl radical reaction with aromatics by dissolved natural organic matter. Environmental Science & Technology, v. 34, pp. 444-449.

Watts, R. J., Bottenberg, B. C., Hess, T. F., Jensen, M. D., and Teel, A. L. 1999a. Role of reductants in the enhanced desorption and transformation of chloroaliphatic compounds by modified Fenton's reactions. Environmental Science and Technology, v. 33, pp. 3432-3437.

Watts, R. J., Foget, M. K., Kong, S.-H., Teel, A. L. 1999b. Hydrogen peroxide decomposition in model subsurface systems. Journal of Hazardous Materials, v. B69, pp. 229-243.


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Attachment B Newsletters & Case Studies

In-situ chemical oxidation

with catalyzed hydrogen

peroxide (CHP) or sodium

persulfate (CSP) are gener-

ally optimized to produce

oxidants such as hydroxyl

radicals and sulfate radicals.

Although these powerful

oxidants are capable of de-

stroying a wide range of

contaminants, there are com-

mon soil and groundwater

contaminants that cannot be

oxidized. These contami-

nants, such as carbon tetra-

chloride (CT), must instead

be reduced in order to be

degraded. As a result, in-situ

treatment of such com-

pounds, particularly in the

presence of DNAPL or as

part of mixed plumes with

compounds that can be oxi-

dized, has presented a chal-

lenging problem.

CHP and CSP are known to

produce superoxide radicals

(O2•-, a chemical reductant)

as part of the chain of reac-

tions associated with these

reagents. Destruction of CT

by CHP and CSP has been

reported, however O2•- pro-

duction generally appears to

have been very inefficient.

Recent reports have found

that under certain condi-

tions, hydrogen peroxide

(H2O2) could be efficiently

catalyzed to produce O2•-,

resulting in degradation of

CT including DNAPL. In

light of these results, Geo-

Cleanse undertook extensive

research of catalysts to produce

O2•- in response to a client seek-

ing a rapid, cost-effective solu-

tion for a site impacted with CT

and a suite of other compounds.

The chemicals of concern in-

cluded compounds that react

well with oxidants (e.g., chloro-

benzene and ethylbenzene), and

compounds that cannot be oxi-

dized or do not react well with

oxidants (e.g., CT and related

chloromethanes), including a

DNAPL phase. The result of

this effort is a new catalytic

system for H2O2, which pro-

duces both superoxide and hy-

droxyl radicals efficiently for in-

situ destruction of a mixed con-

taminant plume and DNAPL.

Previous research by Watts and

coworkers has shown that O2•-

is produced by catalyzing H2O2

with Mn+4 at a pH of about 6.8

or higher. Applying this ap-

proach in the field, however,

would be challenging because

Mn+4 forms an insoluble pre-

cipitate (MnO2) at circumneutral

pH; thus application would re-

quire manipulating large pH

shifts within an

aquifer to maintain

Mn in solution for

distribution and

subsequent precipi-

tation of MnO2, or

perhaps fracture

emplacement of

solid MnO2. Thus

an approach was

developed to more

efficiently distrib-

ute the MnO2 catalyst, and then

controllably react the catalyst

with H2O2 to produce O2•- in-situ.

The approach developed by Geo-

Cleanse comprises the following

steps:

(1) First inject sodium per-

manganate solution. Per-

manganate is an oxidant

that can destroy certain

organic compounds; but

most importantly for this

approach, the permanga-

nate anion is reduced and

manganese is precipitated

throughout the aquifer as

MnO2. The manganese in

MnO2 is predominantly in

the Mn+4 valence state.

(2) Permanganate reduction to

MnO2 preferentially oc-

curs in zones with the

highest organic mass, such

as the portion of the treat-

ment area impacted with

DNAPL and associated

highly elevated soil con-

centrations. Thus this

catalyst is preferentially

precipitated in the zones

requiring treatment.

A New Approach Combining ISCO with Chemical Reduction to Destroy Carbon Tetrachloride DNAPL

and Mixed Plumes

Inside this Issue of ISCO Technology Review

Cover Story (continued) 2

Current Geo-Cleanse projects 2

State of the Art - Comparing Contaminant Oxidant Demand among ISCO Reagents 3

Upcoming Conferences 3

ISC

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Geo-Cleanse International, Inc.

400 State Route 34, Suite B

Matawan, NJ 07747

www.geocleanse.com

Cover Story (Continued from Page 1)

IS CO T ECHNOLOGY RE VIE W

(3) A phosphate buffer at pH of 6.8 to

7.0 is injected next. The phosphate

forms a ligand with colloidal MnO2

and MnO2 surfaces, thus stabilizing

the very rapid catalytic reaction

with H2O2. The phosphate solution

also buffers the pH within the de-

sired range.

(4) H2O2 solution is added next. The

H2O2 reacts with MnO2 to produce

O2•-. The O2•

- degrades the CT and

other chloromethanes.

(5) The H2O2 solution also reacts with

native iron in the formation, and/or

with Mn+2 produced by manganese

redox cycling, to produce hydroxyl

radicals. This is important for deg-

radation of other COCs such as

ethylbenzene, which are destroyed

by hydroxyl radicals but not reac-

tive with O2•-.

Laboratory bench tests were conducted

with soil and groundwater from an indus-

trial site in New Jersey. The soil and

groundwater were impacted with CT, chlo-

roform, methylene chloride, chloroben-

zene, ethylbenzene, and methoxychlor,

including a visible DNAPL phase. Batch

reactor tests controlling all phases (soil,

groundwater, and volatilization; volatiliza-

tion was measured using absorbent car-

tridges) were performed to optimize and

test the approach. Results for CT, chloro-

form, and chlorobenzene from a represen-

tative series of tests are shown in Figures 1

& 2. Results for the aqueous phase (Figure

1) show that baseline VOC concentrations

were reduced by 99.99% for CT and chlo-

roform, and 94.6% for chlorobenzene. The

approach was also found to be extremely

effective for the soil-sorbed and DNAPL

phase; this was evaluated by calculating

the total contaminant mass in each reactor.

The contaminant mass results (Figure 2)

show that VOC mass (excluding volatil-

ized fraction) was reduced by very similar

magnitudes, indicating destruction of soil-

sorbed and DNAPL phases in similar pro-

portions to the aqueous phase.

Experiments demonstrated that all of the

compounds, including compounds de-

stroyed only by reduction (e.g., CT) and

compounds destroyed only by oxidation

(e.g., chlorobenzene), were degraded effec-

tively. Overall de-

struction ranged

from 84% to a nomi-

nal 100% relative to

control samples. The

compounds de-

stroyed by O2•- re-

duction were de-

stroyed slightly

more efficiently than

compounds de-

stroyed by hydroxyl

radical oxidation,

but the efficient

destruction of all

compounds indi-

cates that this ap-

proach can be used

effectively for sites

impacted with a

wide range of oxidi-

zable and reducible

compounds. Analy-

ses also included

sampling for inter-

mediate and final

oxidation products

to elucidate the deg-

radation pathways.

No hazardous inter-

mediate or final

compounds were

detected, including negative analyses for

phosgene (a potential reduction product of

CT).

Based upon these results, a field pilot test is

anticipated to be complete in the spring of

2010.

Current Geo-Cleanse International, Inc. Projects

Phase Contaminants Location

Bench Coal Tar Confidential

Pilot Carbon Tetrachloride NJ

Pilot 1,4-Dioxane NC

Full Petroleum / Coal Tar FL

Full Chlorobenzene NJ

Full Petroleum GA

Full 1,1’-Biphenyl, 1,4-Diphenyl Ether, Toluene NJ

Figure 1. Aqueous VOC Concentrations

Figure 2. VOC Mass

Come visit Geo-Cleanse at the following conferences:

20th Annual Conference on Soils, Sediments, Water, and Energy

San Diego, CA

Upcoming Conferences

V OLU ME 4 Page 3

Comparing Contaminant Oxidant Demand among ISCO Reagents

Remediation of Chlorinated & Recalcitrant Compounds

Conference, Battelle

Monterey, CA

Many factors must be

considered when evaluat-

ing a site and assessing

potential ISCO ap-

proaches. One of the

fundamental decisions to

be made is which oxidant

to utilize. An important

factor in this decision,

which is often over-

looked, is how much

oxidant is required to

destroy target contami-

nant mass and the corre-

sponding impact on cost. At sites with

relatively low contaminant concentra-

tions, the natural oxidant demand is usu-

ally larger than the contaminant oxidant

demand; however at more heavily im-

pacted sites, the contaminant oxidant

demand is generally much larger than the

natural oxidant demand. At sites with

very high contaminant mass, such as coal

tar or DNAPL sites, the overall project

cost is heavily influenced by the cost of

the oxidant required to destroy the con-

taminant. Thus the objective of this article

is to show how contaminant oxidant de-

mand can affect project costs.

For comparison purposes, oxidant de-

mand is compared on a stoichiometric

basis. The radical-initiating oxidation half

-reactions for catalyzed persulfate and

catalyzed peroxide are as follows:

Persulfate:

S2O8-2 + e- → SO4•

- + SO4-2

Peroxide:

H2O2 + e- → OH• + OH-

The key observation is that, for both per-

oxide and persulfate, one mole of oxidant

accepts one mole of electrons and produces

one mole of radicals. The number of radi-

cals required (or electrons removed) from a

target contaminant can also be calculated

from oxidation half-reactions. Reactions for

several common contaminants are as fol-

lows:

TCE:

C2HCl3 + 4H2O → 2CO2 + 3Cl- + 9H+ + 6e-

Benzene:

C6H6 + 12H2O → 6CO2 + 30H+ + 30e-

Naphthalene:

C10H8 + 20H2O → 10CO2 + 48H+ +48e-

Thus on a stoichiometric basis, oxidation of

one mole of TCE produces six moles of

electrons, or in other words requires six

moles of radicals and, therefore, six moles

of oxidant. Similarly, one mole of benzene

requires 30 moles of oxidant, and one mole

of naphthalene requires 48 moles of oxidant.

While the number of moles of peroxide or

persulfate required to oxidize a contaminant

is identical, the weight ratio (in terms of

pounds of oxidant required per pound of

contaminant) is very different. This is be-

cause the formula weight of each oxidant

is different. Sodium persulfate has a for-

mula weight of 238 grams per mole, while

hydrogen peroxide has a formula weight of

34.0 grams per mole. For example, oxida-

tion of 1 mole of TCE requires 0.45 lbs of

peroxide or 3.15 lbs of persulfate. Calcula-

tions for benzene and naphthalene are pro-

vided in Table 1. Due to the difference in

oxidant formula weights, contaminant oxi-

dation requires approximately 7 times

more persulfate by mass than peroxide.

The oxidants also have a significant differ-

ence in cost. Hydrogen peroxide, on a

100% concentration basis and including

ferrous iron catalyst, costs approximately

$1.10 per pound. Sodium persulfate, also

on a 100% concentration basis and includ-

ing caustic catalyst to overcome the oxi-

dant and soil caustic demand, costs ap-

proximately $2.25 per pound. The corre-

sponding costs to destroy one pound of

contaminant are shown at the bottom of

Table 1.

Overall, persulfate costs about 14 times

more than peroxide to destroy the same

contaminant mass. The potential impact of

the reagent cost on overall project cost will

vary with the overall contaminant mass. At

sites with low contaminant concentrations,

the overall impact on cost may not be

large, and other technical factors may have

greater weight in determining oxidant

choice. But at large sites with relatively

high contaminant concentrations, such as a

manufactured gas plant or DNAPL sites

where contaminant mass is measured in

tens of thousands of pounds or more, the

difference in reagent costs can be tremen-

dous. In these cases, catalyzed peroxide

ISCO provides a much better choice from

the perspective of reagent cost.

Factor TCE Benzene Naphthalene

Formula Weight 131.4 78.11 128.2

Moles of Oxidant Required to Destory Contaminant 6 30 48

Pounds of H2O2 per 1 mole of Contaminant 0.45 2.25 3.60

Pounds of Na2S2O8 per 1 mole of Contaminant 3.15 15.74 25.19

H2O2 Cost per 1 lb (including catalyst; 100% basis)

Na2S2O8 Cost per 1 lb (including caustic catalyst)

H2O2 Cost to Destroy 1 mole of Contaminant $0.49 $2.47 $3.96

Na2S2O8 Cost to Destroy 1 mole of Contaminant $7.08 $35.42 $56.68

Table 1: Comparison of Oxidant Requirements and Cost

$1.10

$2.25

State of the Art — ISCO Insights from Geo-Cleanse

26th International Conference on Soils, Sediments, and Water

Amherst, MA

TCEQ’s Annual Environmental Trade Fair and Conference

Austin, TX

experience, together with independ-

ently published results of our work, and

an experienced staff of professionals,

keeps Geo-Cleanse at the top

of the industry.

As the chemical oxidation

field continues to evolve, Geo-

Cleanse has expanded our ser-

vices to incorporate the ad-

vances occurring within the

industry. The Geo-Cleanse®

Process can effectively treat a

wide range of contaminants

and has successfully been ap-

plied in many different litholo-

gies. To date, Geo-Cleanse has

field experience on well over 100 sites

in 28 states, Canada, and Europe.

Since 1995, Geo-Cleanse Interna-

tional, Inc. (Geo-Cleanse) has estab-

lished a reputation as the premier in-

situ chemical oxidation company. Geo-

Cleanse consistently provides quality

service and ensures that the goals of

our treatment programs are achieved.

We have the most experience of any

chemical oxidation firm and were the

first to commercially apply oxidants for

a successful NAPL remediation. Our

We Adapt to the Site-

Specific Conditions

Oxidants: Peroxide, Perman-

ganate, Persulfate

Additives: Surfactants, Chelat-

ing Agents, Stabilizers

Novel Application Methods

In-Situ Reduction

Site-Specific Treatment Goals

Coupling with:

Bioremediation

Extraction

Other Technologies

About Geo-Cleanse International, Inc.

400 State Route 34, Suite B Matawan, NJ 07747


Please visit our website for addi-

tional information or a free site

evaluation:

geocleanse.com

Geo-Cleanse Field Experience (Blue States)

ISCO TECHNOLOGY REVIEW

Volume 3, Issue 2

Innovative Coupling of ISCO Technologies Proves Successful in Orlando

Cover Story (continued) 2

State of the Art - Acidification During Catalyzed Hydrogen Peroxide ISCO 3

Current Geo-Cleanse Projects 3

Upcoming Conferences 3

About Geo-Cleanse 4

Inside this issue of ITR

The Chemical Oxidation

Experts

Soil and groundwater contami-nated by chlorinated solvents posed a potential delay to con-struction of the Orlando Events Center, the future home of the Orlando Magic basketball team. Rapid remediation of a per-chloroethylene (PCE) source area was required in order to prevent construction delays. After a competitive public bid, the City of Orlando contracted Geo-Cleanse International, Inc. (Geo-Cleanse) to provide turn-key in-situ chemical oxidation (ISCO) remediation at site. Geo-Cleanse subcontracted MAC-TEC Engineering and Consult-ing, Inc. to provide local sup-port, including acting as regula-tory liaison for the project team, securing approval of a Limited Scope Remedial Action Work Plan from the Florida Depart-ment of Environmental Protec-tion (FDEP), and overseeing certain field construction activi-ties. Challenges to be addressed as part of the treatment program

were:

Very short time frame – Nov. 2007 award to July 2008 completion, including six months of post-remediation groundwater monitoring.

Presence of potential dense nonaqueous phase liquid (DNAPL) source, with groundwater concentrations greater than 14,000 µg/L of PCE.

Basal clay aquitard – could pose rebound problem with back-diffusion of PCE into groundwater.

Pay for performance contract - The City of Orlando was not obligated to make payments over the initial 50% of con-tract unless Geo-Cleanse achieved and maintained Cleanup Target Levels (CTLs) of 3 µg/L PCE, 3 µg/L of trichloroethylene (TCE), and 70 µg/L of cis-1,2-

dichloroethylene (DCE) in ground-water, and soil leachability criteria of 0.03 mg/kg for PCE.

After careful re-view of the site background inves-tigation data, Geo-Cleanse designed a phased treatment program to meet the CTLs in the timeframe neces-

sary to avoid development de-lays. The remediation program incorporated a “treatment train” consisting of three remediation phases:

Phase 1 consisted of injection of catalyzed hydrogen peroxide (CHP) for primary source re-duction.

Phase 2 consisted of injection of sodium permanganate to achieve the CTLs and prevent back-diffusion from the under-lying clay aquitard.

Phase 3 consisted of excava-tion of shallow vadose zone soil impacts.

The ISCO component called for 72 injection wells installed across three depth intervals between approximately 10-40 feet below grade, in an approximate 130 feet x 80 feet area (Figure 1). The aquifer lithology consists of sand to silty sand with an underlying

Figure 2: Our Patented Mixing Head

Figure 1: Treatment Area Map

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Cover Story (Continued from Page 1)

ISCO TECHNOLOGY REVIEW

clay aquitard at a depth of 40 feet. Injec-tion well installation was completed during the period of November 27 to December 15, 2007. The injection wells were then allowed to cure for two weeks.

The first phase of remediation consisted of injecting 85,000 gallons of CHP solution over the period from January 2-26, 2008 (Figure 2). Geo-Cleanse conducted inten-sive groundwater and offgas sampling to ensure appropriate geochemical conditions for an effective CHP injection existed in the treatment area, and to evaluate treat-ment progress. Measurements of volatile organic compounds (VOCs) in the head-space over a groundwater sample, as taken with a photoionization detector (PID), pro-vide a semi-quantitative measure of VOC concentration in the groundwater. Figure 3 is a chart of the PID readings of groundwa-ter samples from the four monitoring wells in the source area. The PID readings show an initial spike in headspace PID measure-ments related to desorption of VOCs from the aquifer matrix, followed by subsequent degradation of the PID measurements to non-detectable levels over the treatment period. These data confirm that the CHP component was complete, and the next remediation phase was initiated.

One week was allowed for residual hydro-gen peroxide to degrade after completing the CHP injection before beginning the permanganate injection. The same network of injection wells installed for the CHP injection was also utilized for the perman-ganate. This second phase of remediation consisted of injecting 21,000 gallons of 4% sodium permanganate solution over the period from February 4-10, 2008. Field monitoring for sodium permanganate in-

jection consisted of collecting groundwater samples for visual analysis to ensure uniform distri-bution of the permanganate re-agent. Permanganate (recognized by its characteristic purple color) was found throughout the treat-ment area following the injection. The post-injection groundwater monitoring period began after completion of the permanganate injection.

The third phase of remediation consisted of soil removal from two areas at which PCE was de-tected at concentrations exceed-

ing the soil leachability criterion of 0.03 mg/kg. A total of approximately 94 tons of soil was removed from two areas over the period from February 25-27, 2008. During the re-moval action, a PVC pipe attached to an ap-parent floor drain system was discovered at

the site (Figure 4). The pipe was found to contain residual sludge and exhibited ele-vated PID readings, and was located directly over the groundwater source areas, and thus is the presumed source. The pip-ing and associated bedding was, therefore, also removed from accessible portions of the site. After receipt of post-excavation sampling results, the excavation was backfilled on March 7, 2008.

The post-treatment performance sampling program consisted of three groundwater sampling events, conducted on February 14, 2008 (4 days after injection), April 23, 2008 (73 days after injection), and July 23, 2008 (164 days) after injection, with a sup-plemental sampling event on

August 5, 2008 (177 days after injection). With one exception, the VOC concentrations in all five of the performance monitoring wells have been reduced to below the CTLs. The total VOC concentration (consisting of the summed PCE, TCE and DCE concentra-tions) is plotted in Figure 5 for the two moni-toring wells exhibiting the highest pre-injection VOC concentrations. During the July 23rd event, PCE was detected at 11 mg/L in MW-5 and was confirmed with a second analysis. MW-5 is a shallow well located adjacent to the soil excavation area, thus the VOC detection is likely associated with the soil removal. Additional treatment was fo-cused in the area of MW-5, and a new sample was collected on August 5, 2008. All VOCs were below CTLs. The injection and moni-toring wells were then abandoned in accor-dance with Florida regulations by August 8, 2008 to allow construction.

This treatment program was successful in obtaining Florida CTLs for the target com-pounds and was completed in a timeframe in order to avoid delays in construction. All pre-construction permitting and field work to achieve the CTLs in all media, including LSRAP submittal, regulatory approval, drill-ing, injection, soil removal, and backfill, was completed by March 7, 2008, approximately 4.5 months after contract execution. The FDEP has approved the results and construc-tion has begun. This project demonstrates how DNAPL sites can be successfully reme-diated with a “treatment train” approach util-izing ISCO. Rarely can one single technol-ogy provide a complete remedy. As this case study demonstrates, Geo-Cleanse has the experience and capability to couple technolo-gies, and to undertake innovative approaches, to achieve cleanup goals.

Figure 3: Monitoring Well Headspace PID

Figure 4: Presumed Source of PCE Contamination

Figure 5: Post-Treatment Groundwater Results

Come visit Geo-Cleanse at the following conferences:

International Conference on Soils, Sediments, & Water

Amherst, MA.

Upcoming Conferences

VOLUME 3, ISSUE 2 Page 3

State of the Art - ISCO insights from Geo-Cleanse:

Acidification during Catalyzed Hydrogen Peroxide ISCO

Current Geo-Cleanse Projects

Remediation of Chlorinated & Recalcitrant Compounds

Monterey, CA

Environmental Trade Fair and Conference Austin, TX.

Conference on Soil, Sediments, and Water

San Diego, CA

Florida Remediation Conference Orlando, Fl

Annual Florida Brownfields Conference

Florida

There are many choices today regarding se-lection of oxidants and catalytic systems. Catalyzed hydrogen peroxide (CHP) is argua-bly the most versatile oxidant, and an impor-tant question to be addressed during system design is whether acidification is necessary as part of the treatment. Studies of classical Fenton’s reagent systems found that treat-ment was generally most effective at acidic pH conditions, typically at a pH of 3-4. Some practitioners try to differentiate themselves as using “neutral” or “cool” CHP as opposed to an “acidified” CHP approach, and claim more efficient treatment than an acidified approach. However the answer to the “which is best?” question lies with consideration of site-specific conditions and treatment objec-tives. This article explores some of the ad-vantages and disadvantages of acidification as part of CHP ISCO.

Hydroxyl radicals (which are the primary reactants with CHP) can be generated at nearly any pH. Thus important considerations are how pH affects, or is affected by, (1) lithology of the soil and aquifer matrix, (2) the catalyst system, and (3) scaven-gers that affect treatment effi-ciency. These factors are i n t e r r e l a t e d , and should not be considered independently.

The advantages of an acidic pH catalyst sys-tem over a circumneutral pH catalyst system include:

Transition metals are required to catalyze peroxide to produce hydroxyl radicals. Under acidic conditions, transition metals

are kept in solution rather than precipitating as oxyhydroxides. Naturally occurring tran-sition metals are also released from the aq-uifer matrix, thus the amount of transition metals that must be added is reduced under acidic conditions.

Bicarbonate interference is re-duced. Hydroxyl radicals react with dissolved bicarbonate in groundwater. The reaction rate of the hydroxyl radical with a bicarbonate is slower than for reaction of hydroxyl radical with common contaminants; however, if dissolved bicarbonate is present at relatively high concentrations (200 – 400 mg/L), then radicals may be hundreds or thousands of times more likely to react with bicarbonate than with the contaminants, and thus may significantly reduce treatment effectiveness. Bicarbonate is eliminated at a pH of about 5.4, thus the hydroxyl radicals are utilized more efficiently for contaminant destruction under mildly acidic pH conditions.

At circumneutral pH, transi-tion metals are typically added in a chelated form. This offers both advantages and disadvantages:

Treatment can be accom-plished in carbonate-rich aquifers. Under heavily im-pacted (NAPL) conditions, the contaminant concentra-

tions are typically high enough that bicar-bonate interference is less significant. This may remain as an advantage until dissolved contaminant concentrations are reduced (for example, to the 1-10 mg/L range), and bi-carbonate interference again becomes sig-nificant.

Chelating agents react with hydroxyl radi-

cals. Thus when a chelated metal is added, often at a concentration much higher than the target contaminant, the chelating agent becomes a hydroxyl radical scavenger and

contaminant treat-ment efficiency is reduced. At neutral pH, radical scaveng-ing from dissolved bicarbonate and chelators will sig-nificantly reduce treatment efficiency.

Many commonly used chelating agents may also be considered environmental hazards if not fully destroyed by the catalyzed perox-ide. For example, EDTA does not readily biodegrade in groundwater, and has been linked to mobilization of metals; and NTA is a suspected carcinogen.

Transition metal injection must be sustained throughout the treatment. At circumneutral pH, once the chelating agent is destroyed and the transition metal has reacted with peroxide, the metal is oxidized and will precipitate as an insoluble oxyhydroxide. Additional transition metal injection is therefore required in order to continue to catalyze the peroxide.

The decision to utilize an acidic pH catalyst system or a circumneutral, chelated metal catalyst system requires consideration of site-specific issues. Both catalyst systems have advantages and disadvantages, and there is no “best” catalyst system applicable to all sites. Geo-Cleanse has considerable experience with both acidic and circumneutral catalyst sys-tems. Our goal is to provide the most effective treatment, and will always optimize the cata-lyst to best fit the site-specific conditions and treatment objectives.

“Our goal is to provide the most effective treatment, and will

always optimize the catalyst to best fit the site-specific conditions

and treatment objectives.”

“...important considerations are how pH affects, or is affected by, (1) lithology of the soil and aquifer matrix, (2) the

catalyst system, and (3) scavengers that affect treatment efficiency. These

factors are interrelated, and should not be considered independently.”

Scale

Oxidant

Contaminant

Location

Bench CHP Carbon

Tetrachloride NJ

Bench CHP Coal Tar NJ

Pilot CHP TCE, BCEE NJ

Pilot CHP Dioxane NC

Full CHP Petroleum /

Coal tar FL

Full CHP Chlorobenzene NJ

Full CHP Petroleum NJ

a successful NAPL remediation. Our experience, together with independ-ently published results of our work, and an experienced staff of professionals,

keeps Geo-Cleanse at the top of the industry. As the chemical oxidation field continues to evolve, Geo-Cleanse has expanded our ser-vices to incorporate the ad-vances occurring within the industry. The Geo-Cleanse® Process can effectively treat a wide range of contaminants and has successfully been applied in many different lithologies. To date, Geo-Cleanse has field ex-perience on well over 100 sites

in 28 states, Canada, and Europe.

Since 1995, Geo-Cleanse Interna-tional, Inc. (Geo-Cleanse) has estab-lished a reputation as the premier in-situ chemical oxidation company. Geo-

Cleanse consistently provides quality service and ensures that the goals of our treatment programs are achieved. We have the most experience of any chemical oxidation firm and were the first to commercially apply oxidants for

We Adapt to the Specific Site Conditions

Oxidants: Peroxide, Perman-ganate, Persulfate

Additives: Surfactants, Che-lating Agents, Stabilizers

Novel Application Methods

In-Situ Reduction

Coupling with:

Bioremediation

Extraction

Other Technologies

About Geo-Cleanse ...

The Chemical Oxidation Experts

400 State Route 34, Suite B Matawan, NJ 07747


Please visit our website

www.geocleanse.com to view our case studies or for a free site evaluation.

Geo-Cleanse Field Experience (Blue States)

Geo-Cleanse Remediation Summary Augusta, GA

Former MGP Plant Coal Tar

Overview: Geo-Cleanse International, Inc. (Geo-Cleanse) was contracted to perform an in-situ chemical oxidation (ISCO) full-scale treatment program to remediate by-product like material (BPLM) on the on- and off-site properties surrounding a former manufactured gas plant (MGP) facility in Augusta, Georgia. BPLM is identified as “free phase” coal tar residuals measured as BTEX (benzene, toluene, ethylbenzene and xylenes) and PAHs (polycyclic aromatic hydrocarbons), which are MGP-specific constituents. Results from the pilot ISCO treatment program indicated these constituents were amenable to chemical oxidation using Fenton’s reagent. Site Background Characteristics: This site was a former MGP located in Augusta, Georgia. From the early 1800s until the 1950s, the MGP site was used to produce gas from coal, coke, or oil. During the gas productions process, various residuals such as tars, liquors, sludges, coal fragments and gas purifying wastes were produced, some of which were released into the soil and groundwater. Treatment Program Design: The full-scale ISCO treatment program was designed to remediate BPLM mass to the extent practicable. Treatment to the extent practicable was defined as the point where no significant BPLM reduction will occur with further treatment. Activities at the site consisted of four main phases of implementation: injection well installation; mass calculations and hydrogen peroxide proportioning; injection; and post-treatment sampling. Each phase of the treatment program was specifically designed to attain the overall goal of the treatment program and to meet the criteria for closure at this site. Injection Well Installation: Injection well installation for the full-scale treatment program at the Augusta site began on July 6, 2004 and was completed on October 27, 2004. The installation phase consisted of approximately 88 days of active installation. Over this time period, 686 injection wells were installed across the site in a maximum of three vertical treatment intervals. In addition, the 43 injection wells installed for the pilot treatment program at this site were utilized as active injection points for the full-scale, equating to a total of 729 injection wells. The injection wells were placed on an approximate 15-ft x 15-ft grid pattern across the majority of the site. In addition to the injection wells, 33 vent wells were installed at this site. The depths and amounts of injection well layers varied based on the presence of BPLM. Injection wells were installed and screened where BPLM was observed. The entire treatment area was subdivided into 39 blocks, which each consisted of 43 injection wells or less. These divisions were implemented to simplify the sampling, injection and data management activities for the site. Baseline Sampling and Mass Calculations: During injection well installation, several injection well locations were continuously cored and sampled. Soil samples were obtained in 5-ft increments from several locations across the site. A minimum of 20% of the injection wells were sampled in order to define the lateral and vertical extent of the contaminant mass present at the site. These samples were analyzed by STL’s Mobile

Laboratory. The samples were analyzed for BTEX using EPA Method 8260B and PAHs using EPA Method 8270C. Using the analytical data from these samples, a target volume was calculated for each injection well at the site, which was based on a 22:1 ratio of hydrogen peroxide to contaminant mass. Every injection well was assigned a BPLM mass and a corresponding volume of hydrogen peroxide was calculated. If the mass volume calculated was less than the minimum amount required to establish an effective radius of influence (ROI), then a volume of 400 gallons of 12.5% hydrogen peroxide was used for that injection well.

Remediation Operations: The injection activities implemented during the full-scale treatment program took place in the following stages:

• 22:1 Ratio/Minimum Injection (Target Volumes) • Photoionization Detector (PID) Headspace Chasing • Peroxide Stability • 21-Day Post-Treatment Monitoring • Long Term Monitoring

These stages of injection were developed to demonstrate that the performance criteria for treating BPLM to the extent practicable were achieved. A description of the treatment criteria is described in more detail below. Each day prior to oxidant injection, groundwater samples were obtained from all of the injection wells within an active treatment block and analyzed for pH, alkalinity, iron, and hydrogen peroxide concentrations, temperature and PID headspace. This process continued throughout the program on a daily basis to monitor the changes in groundwater chemistry and volatile constituents. Once the delivery of the target volume to each injection well was complete in an active block, treatment focused on the injection well locations with PID headspace readings in groundwater greater than 50 ppm. Results from the pilot ISCO treatment demonstrated that PID headspace in groundwater was directly proportional to remaining VOC concentrations. Treatment to the extent practicable was achieved when every injection well within an active block had headspace readings below 50 ppm, thus oxidant delivery refocused on the locations that did not meet this criteria. Once all injection wells within an active treatment block were all below 50 ppm, Geo-Cleanse conducted a hydrogen peroxide stability test. This test involved injecting hydrogen peroxide over the course of one day to obtain a concentration of peroxide equal to or greater than 250 ppm at each injection well for 8 hours. The following day groundwater samples verified that sufficient hydrogen peroxide concentrations existed in each injection well within the treatment block. After the concentration of hydrogen peroxide decreased to 2.5 ppm or below in every injection well, 21-day post-treatment monitoring began, which consisted of obtaining daily PID headspace readings. If headspaces remained below 50 ppm during this 21-day period, the final treatment criterion was effectively met and the block was considered closed. However, select locations within each treatment block were still monitored weekly until active treatment in all the blocks across the site was complete. The long-term monitoring served as an assessment of BPLM rebound and as a final check that the block was treated to the extent practicable. Including the standard ISCO remediation operations, Geo-Cleanse also implemented other innovative remedial technologies and procedures to increase the efficiency of the overall ISCO program. Geo-Cleanse created an above ground piping network designed to contain all fluids

generated during the treatment program. As injection activities proceeded, off-gases created from the reaction caused fluids to mound from the subsurface through the injection wells. In order to manage these mounding fluids, controls were placed on each injection well to direct the groundwater into pipes of the water collection system. At the end of the system, the groundwater was directed through an oil water separator and then into a frac tank. Geo-Cleanse personnel treated and discharged the groundwater on-site eliminating many of the transport, treatment and disposal costs. Geo-Cleanse personnel also used vacuum extraction to reduce the coal tar mass, influence the direction of injected oxidant solution and create larger pathways for oxidant migration. During the treatment program, Geo-Cleanse harnessed the exothermic nature of Fenton’s reagent to desorb and extract some of the free phase and residual product. Geo-Cleanse used a vacuum truck equipped with a multiple port manifold system to extract the liberated contaminants, using the injection wells as extraction points. These collected materials were then discharged into the frac tank portion of the water collection system and treated. This system helped to remove the free phase and residual product and opened up the site for better oxidant delivery. Treatment Results: The full-scale treatment program conducted at the former MGP site in Augusta, Georgia met the criteria required to establish that the BPLM mass at the site was treated to the extent practicable. Based on the injection activities and groundwater quality data, the full-scale treatment program conducted by Geo-Cleanse obtained closure in each of the 39 blocks on the site. Therefore, the criteria for treating BPLM mass to the extent practicable was achieved and maintained for the length of the treatment program. Summary: Injection at the site began in Block A on November 3, 2004, where the pilot was originally conducted. Injection activities were completed in Block AH on September 14, 2005. The entire treatment program from start to finish included the injection of approximately 2.1 million gallons of 12.5% hydrogen peroxide and a site-specific catalyst solution. The full-scale treatment program at the former MGP site in Augusta, Georgia was completed on October 9, 2005. This summary sheet is intended to provide a general overview of the referenced site. For more detailed information, please contact us at (732) 970-6696.

Geo-Cleanse Remediation Summary Savannah, GA

Former MGP Coal Tar

Overview: Geo-Cleanse International, Inc. (Geo-Cleanse) was contracted to perform a full-scale in-situ chemical oxidation (ISCO) treatment program to treat by-product like material (BPLM), which is a manufactured gas plant (MGP) specific constituent. BPLM is identified as “free phase” coal tar residuals measured as BTEX (benzene, toluene, ethylbenzene and xylenes) and PAH (polycyclic aromatic hydrocarbons). Results from the pilot ISCO treatment program indicated these constituents were amenable to chemical oxidation using Fenton’s reagent. Site Background Characteristics: This site was a former MGP located in Savannah, Georgia. From the early 1800s until the 1950s, the MGP site was used to produce gas from coal, coke, or oil. During the gas productions process, various residuals such as tars, liquors, sludges, coal fragments and gas purifying wastes were produced, some of which were released into the soil and groundwater. Program Goals: The goal of the treatment program was to reduce the BPLM contamination in the groundwater and soil within the targeted depth intervals to the extent practicable. Treatment to the extent practicable is defined as the point where no significant BPLM reduction will occur with further treatment. Activities at the site consisted of four main phases of implementation: injection well installation; mass calculations and hydrogen peroxide proportioning; injection; and post-treatment sampling. Each phase of the treatment program was specifically designed to attain the overall goal of meeting the criteria for closure at this site. Injection Well Installation: The injection well installation for the full-scale treatment program at the site began on January 6, 2005 and was complete on April 30, 2005. This phase consisted of approximately 95 days of active installation. Over this time period, 1,238 injection wells were installed on an approximate 15-foot by 15-foot grid pattern, across a maximum of five vertical treatment intervals (see attached map). In addition, the 45 injection wells that were installed for the pilot treatment program at this site were utilized as active injection points for the full-scale. 74 vent wells were also installed at this site.

The depths and amounts of injection well layers varied based on the presence of BPLM. Injection wells were installed and screened where BPLM was observed. Once an injection well was installed, four adjacent injection wells were installed in the same screened interval to ensure sufficient oxidant solution contact with the contaminated area. The entire treatment area was subdivided into 28 blocks, with each consisting of 91 injection wells or less. These divisions were implemented to simplify the sampling, injection and data management activities for the site.

Baseline Sampling and Mass Calculations: During installation, several injection wells were continuously cored and sampled. Soil samples were obtained in 5-foot increments from approximately 20% of the injection wells across the site, in order to define the lateral and vertical extent of the contaminant mass present at the site. The

samples were analyzed for BTEX using EPA Method 8260B and PAHs using EPA Method 8270C. Using the analytical data from these samples, injection wells were assigned a contaminant mass and a target volume of hydrogen peroxide for each injection well was calculated. The volume of hydrogen peroxide required was based on a 22:1 ratio of hydrogen peroxide to contaminant mass. This ratio was proven to be effective during the pilot ISCO treatment program. If the mass volume calculation was less than the minimum amount of hydrogen peroxide required to be injected to establish the radius of influence, a minimum volume of 480 gallons of 12.5% hydrogen peroxide was used for that injection well.

Once mass volume calculations were achieved, the injection activities were implemented and the full-scale treatment program took place in the following stages:

• 22:1 Ratio/Minimum Injection (Target Volumes) • Photoionization Detector (PID) Headspace Chasing • Peroxide Stability • 21-Day Post-Treatment Monitoring • Long Term Monitoring

These stages of injection were developed to demonstrate that the performance criteria for treating BPLM to the extent practicable were achieved.

Remediation Operations: Each day prior to oxidant injection, groundwater samples were obtained from all of the injection wells within an active treatment block and analyzed for pH, alkalinity, iron and hydrogen peroxide concentrations, temperature, and PID headspace. This process continued throughout the program on a daily basis to monitor the changes in groundwater chemistry and volatile constituents. Once the delivery of target volume to each injection well was complete in an active block, treatment focused on the locations with PID headspace readings in groundwater greater than 50 ppm. Results from the pilot ISCO treatment demonstrated that PID headspace in groundwater was directly proportional to remaining VOC concentrations. Treatment to the extent practicable was achieved when every injection well within an active block had a headspace reading below 50 ppm, thus oxidant delivery refocused on the locations that did not meet this criteria. Once all injection wells within an active treatment block were all below 50 ppm, Geo-Cleanse conducted a hydrogen peroxide stability test. This test involved injecting hydrogen peroxide over the course of one day to obtain a concentration of peroxide equal to or greater than 250 ppm at each injection well for 8 hours. The following day groundwater samples verified that sufficient hydrogen peroxide concentrations existed in each injection well within the treatment block. After the concentration of hydrogen peroxide decreased to 2.5 ppm or below in every injection well, 21-day post-treatment monitoring began, which consisted of obtaining daily PID headspace readings. If headspaces remained below 50 ppm during this 21-day period, the final treatment criterion was effectively met and the block was considered closed, however select locations within each treatment block were still monitored weekly until active treatment in all the blocks across the site was complete. The long-term monitoring served as an assessment of BPLM rebound and as a final check that the block was treated to the extent practicable.

Summary and Treatment Results: Injection at the site began on February 6, 2004 and injection activities were completed on January 17, 2005. A total of 7 injection rigs were used throughout the duration of the injection program. The entire treatment program from start to finish included the injection of approximately 3.1 million gallons of 8% hydrogen peroxide and a site-specific catalyst solution. The treatment criteria for treating BPLM mass to the extent practicable was achieved and maintained for the length of the treatment program across the entire site. Based on the injection activities and groundwater quality data, the full-scale treatment program conducted by Geo-Cleanse obtained closure in each of the 28 blocks on the site. The full-scale treatment program at the former MGP site in Savannah, Georgia was completed on February 17, 2005. This summary sheet is intended to provide a general overview of the referenced site. For more detailed information, please contact us at (732) 970-6696.

Edwards AFB Abstract

Page 1 of 3

Permanganate In-Situ Chemical Oxidation of TCE at Edwards Air Force Base, California Todd Battey, Earth Tech, 100 Contractor Hill Road, Edwards AFB, CA 93523 Telephone: (661) 258-7720; Fax: (661) 258-7725; E-mail: [email protected] Kimberly Coleman, Earth Tech, 695 River Oaks Parkway, San Jose, CA 95134 Telephone: (408) 232-2872; Fax: (408) 000-0000; E-mail: [email protected] Dan Bryant, Geo-Cleanse International, Inc., 400 State Route 34, Suite B, Matawan, NJ 07747 Telephone: (732) 970-6696; Fax (732) 970-6697; E-mail: [email protected] ABSTRACT A treatability study of in-situ chemical oxidation (ISCO) using permanganate was conducted in a bedrock aquifer at Site N7, NASA Dryden Flight Research Center, Edwards Air Force Base. The objectives were to achieve contaminant destruction, determine the injection radius of influence, optimize injection methods for bedrock, monitor persistence of permanganate, and evaluate groundwater quality effects. The study area was approximately 100 ft by 50 ft and 100 ft deep. 7,450 gallons of 1.8% potassium permanganate solution were injected into 8 screened wells and 2 boreholes over 5 days. Groundwater samples collected periodically for 60 days following treatment were analyzed for permanganate, metals, and volatile organic compound concentrations. Trichloroethylene and cis-1,2-dichloreothylene remained below detection (from a pre-injection cumulative concentration of 7,210 ug/L). Acetone (presumably an oxidation product) was detected at up to 3,000 ug/L following injection and has attenuated to <460 ug/L. Elevated metal concentrations following treatment have decreased to <80% of their post-injection maxima, with the exception of chromium and nickel. Permanganate degradation rates yield an average half-life of 19 days, and permanganate should degrade below visible concentrations (<0.5 mg/L) in approximately 283 days. Permanganate ISCO appears effective and viable for treatment of chlorinated hydrocarbons at Edwards Air Force Base. Introduction NASA Dryden is located at Edwards Air Force Base, approximately 60 miles north-northeast of Los Angeles, California. NASA Dryden occupies approximately 800 acres on the northwestern edge of Rogers Dry Lake, and consists of administrative, research, laboratory, service, hangar, and storage buildings for support of aeronautical research operations. Site N7 contains two former drum storage areas used by various facility management contractors and a paint shop. Site N7 has approximately 5 feet of silty sand overlying granitic bedrock. The first approximately 10 feet of bedrock is moderately weathered with progressively greater competence with increasing depth. Primary fractures strike northwesterly/southeasterly with a southwesterly dip, and secondary fractures strike north-northeasterly/south-southeasterly with a northwesterly dip. The dip magnitudes are typically 60 to 90 degrees. Apertures generally range from 0.08 to 0.77 inches. Depth to groundwater is approximately 10 feet. Groundwater flow is easterly. Geophysical and hydraulic tests conducted at Site N7 yielded hydraulic conductivity estimates ranging from 8.7 x 10-8 to 1.3 x 10-4 cm/sec, with no consistent trends with depth. Pump tests yielded average transmissivity of 0.004 to 0.035 ft2/min. Groundwater quality at Site N7 is alkaline and slightly saline, with groundwater pH ranging from 7.6 to 8.5, total alkalinity ranging from 383 to 552 mg/L, and chloride concentration ranging from 465 to 1,610 mg/L.


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Trichloroethylene (TCE) and its natural degradation product cis-1,2-dichloroethylene (CIS) were detected at Site N7 with maximum baseline concentrations of 6,500 ug/L and 710 ug/L, respectively. Packer tests indicate that TCE and CIS concentrations decreased with depth, with maxima of 45 ug/L TCE and 120 ug/L CIS at depths deeper than 100 ft below grade. Treatability Study Approach, Implementation and Monitoring Six existing screened wells and 2 new wells were used as injection points. The new wells were left as open boreholes (except for shallow casing to prevent overburden collapse) to provide maximum injection flexibility. Packer testing and geophysical logging were conducted on each new borehole to evaluate the vertical distribution of contaminants and potential transmissive zones within the bedrock aquifer. Project design included an injection volume of approximately 1,000 gallons of 2% KMnO4 solution to each of the 8 locations. This volume was based upon dissolved VOC concentrations and corresponding estimate of VOC mass within the treatment area, plus a conservative excess for inefficiencies. Based upon oxidation stoichiometry and a weighted average ratio of KMnO4 mass to VOC mass of 2.6:1 (based upon observed TCE and CIS concentrations), the minimum mass of solid KMnO4 required was estimated at approximately 31.4 lbs. This estimate assumed perfect reaction efficiency and did not allow for natural inefficiencies due to competing reactions and delivery. A ratio of 40:1 was considered a conservative estimate to ensure complete delivery and oxidation, thus a KMnO4 mass of 1,256 lbs was estimated. A mobile treatment unit was staged at the site, with tanks, pumps, gauges and flow control valves to prepare and deliver reagents safely and effectively. Specially designed mixing heads were attached to the riser pipe of packers installed in the injection wells. The injection process was dynamic and several variables (including injection rate, pressure, and use of air to enhance reagent dispersion) were modified to evaluate optimal injection conditions. Injection rate ranged from <0.25 gpm to > 2 gpm, injection pressure (at which liquid reagents are delivered) ranged from 5 psi to 70 psi, and air was also introduced at pressures ranging up to 70 psi and flow rates ranging up to 4 cfm. Treatment Operations and Results Field injection operations were conducted from August 21-25, 2000. A total of 7,450 gallons of 1.8% potassium permanganate solution (equivalent to 1,102 lbs of solid KMnO4) were injected. Field monitoring during the injection indicated that offgases were not produced in measurable quantities, and thus offgas monitoring for CO2, O2, volatile organics, and LEL were discontinued. Groundwater samples collected each morning were analyzed for manganese, chloride, pH, and permanganate, of which only permanganate concentrations were found to be useful field indicators of reaction or reagent distribution. Groundwater samples for VOC and metals analyses were collected at three stages during the treatability study: during packer testing to evaluate the vertical distribution of VOCs, prior to injection to establish baseline conditions, and 3 post-injection in three rounds (at 5 days, 30 days, and 60 days) to evaluate performance. Destruction of the TCE and CIS at the site was complete, and TCE and CIS have remained below detection for at least 60 days. Acetone, however, appeared at up to 3,000 ug/L following injection, suggesting formation as an oxidation product. Acetone has not been reported as a


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permanganate oxidation product of chlorinated ethenes and was not detected in pre-injection bench scale studies of TCE oxidation in groundwater from other sites at Edwards AFB. Determination of the radius of influence (ROI) was one of the primary objectives. The best ROI indicator was presence or absence of permanganate, which is readily detected in nearby wells. The second constraint is groundwater mounding, indicating connectivity between an injection well and nearby monitoring wells. During the treatability study, the first evidence of groundwater mounding was followed within a few hours by the appearance of permanganate in the well. Monitoring results indicated a horizontal ROI between 30 and 55 feet and a vertical ROI of at least 28 feet. The permanganate concentration data were utilized to determine the rate of permanganate degradation at the site. An initial rates method was utilized to calculate an average rate constant (k) of 0.036 day-1 (assuming a pseudo-first-order reaction), with a corresponding average half-life of approximately 19 days. The long-term persistence of permanganate was estimated from the rate constant using a first-order decay law. The point at which permanganate is no longer visible (approximately 0.5 mg/L) was taken as the final concentration, and the average maximum permanganate concentration (13,509 mg/L) was taken as the initial concentration, yielding an estimate of 283 days until permanganate is no longer visible. Concentrations of most metals were elevated following treatment, but all except chromium and nickel have decreased significantly (>80%) over the 60-day sampling interval relative to the post-injection maximum concentrations. Chromium concentrations in the injection wells doubled from averages of 14,300 to 29,320 ug/L between the 5-day and 30-day post-injection sampling rounds, but then subsequently decreased by 29% to 20,804 ug/L in the 60-day round. Nickel, in contrast, has been variable but remained elevated. Regardless of the mechanism that resulted in the elevated metals (colloidal materials associated with the permanganate or liberated from the formation), the heavy metal concentrations within the treatment area are only anticipated to remain elevated above background concentrations as long as the permanganate persists. Chromium in particular, which may exist in the most soluble hexavalent state, will reduce and precipitate under the alkaline groundwater conditions at Edwards AFB. Overall Conclusions After a 5-day injection period, TCE and CIS have remained non-detectable (reduced from 7,210 ug/L) for 60 days following treatment. Temporary acetone and metals increases observed in groundwater following treatment attenuated rapidly. Only chromium and nickel have remained elevated 60 days after treatment, however neither are stable in alkaline aquifers and are anticipated to attenuate as the permanganate degrades. The purple color imparted to groundwater by permanganate will persist as long as permanganate concentrations remain >0.5 mg/L, which is anticipated to be approximately 283 days based upon permanganate degradation measurements. Overall, permanganate treatment appears to offer an effective and viable remedial alternative for chlorinated solvents dissolved in groundwater at Edwards AFB.

Site Background:For over 100 years, this site was a chemical companylocated in Garfield, NJ. The 2,025 sq ft area is covered by aconcrete cap and the geology of the treatment areaconsists of fine to medium grained sand. Depth togroundwater is approximately 10 feet below groundsurface (ft bgs). During site investigations, toluene, 1,1’-biphenyl, and diphenyl ether were detected exceeding theapplicable NJDEP soil and groundwater remediationstandards. The goal of the in-situ chemical oxidation (ISCO)treatment program was to achieve source reductionwithout any negative impact to the groundwater.


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Site Summary: Garfield Chemical Site

Design & Treatment:Geo-Cleanse International, Inc. (Geo-Cleanse) was contracted to design and implement the ISCO field treatmentprogram. Due to site-specific conditions, Geo-Cleanse determined that catalyzed hydrogen peroxide (CHP) would bethe most appropriate oxidant. The primary field treatment area was approximately 45 ft x 45 ft, 6 ft thick, at a depthinterval from 6 to 12 ft bgs. A total of 11 injection wells and 4 vent wells were installed utilizing direct pushtechnology. Soil borings were also collected for visual soil characterization and to confirm the depth of the treatmentinterval. During soil boring collection and baseline sampling, light non-aqueous phase liquids (LNAPL) were present. Atotal of approximately 29,150 gallons of 8 % hydrogen peroxide and catalyst were injected during a course of 14 days.

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Treatment Results:Our routine process monitoring and sampling ensureda safe and efficient process. Groundwater datacollected during active injection showed thatconditions conducive to a CHP treatment wereestablished. Offgas monitoring data indicated thatoxidation was occurring, resulting in elevated carbondioxide levels. Following the treatment program,LNAPL was eliminated and the soil and groundwatergoals were achieved. Based on the success of thetreatment program, a No Further Action (NFA) letterfor the soil is expected in the near future. Monitorednatural attenuation of groundwater will be used toachieve final groundwater goals.

Pre-Treatment Soil Borings


Summary:Daily process monitoring was conducted during theinjection program to ensure a safe and efficient process. Offgas monitoring data indicated that oxidation was occurring,resulting in elevated carbon dioxide concentrations. Thereagents were successfully distributed throughout thetargeted treatment intervals, and the structures on-sitewere not compromised. Performance monitoring indicatedthat the contaminant concentrations were below the NJDEPSSC and the property owner received a No Further Actionletter.

Site Background:Geo-Cleanse International, Inc. (Geo-Cleanse) wascontracted to perform a full-scale in-situ chemical oxidation(ISCO) treatment program at a residential home in NewJersey. After the removal of an underground storage tank,post-treatment samples revealed residual vadose zone soilcontamination. The contaminants of concern were totalpetroleum hydrocarbons (TPH), which were above the NewJersey Department of Environmental Protection SoilCleanup Criteria (NJDEP SCC) of 10,000 mg/kg. Followingexcavation activities, soil data indicated that contaminantconcentrations were still above the NJDEP SCC, atapproximately 38,000 mg/kg. In order to protect thefoundation of the house and reach final cleanup goals, anin-situ chemical oxidation treatment program wasimplemented.



Site Summary: Residential NJ Home


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Design & Treatment:Based on the site access limitations and the contaminants present, Geo-Cleanse determined that catalyzed hydrogen peroxide (CHP) would bethe most appropriate oxidant for the site to reach the cleanup goals inthe desired time frame. The treatment program targeted an intervalfrom approximately 10 to 19 feet below ground surface (ft-bgs). A totalof 8 permanent injection wells were installed utilizing direct-pushtechnology. The injection wells were installed as nested points, whereeach point contained two wells per bore hole. The nested points helpedto reduce well locations and drilling costs. The injection programconsisted of eight days of active injection and a total of 12,000 gallonsof 10.5% concentration of CHP was injected across the site.


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Treatment Results:The treatment program was conducted on May 3rd and 4th,2010. Post-treatment groundwater analytical resultsconfirmed benzene reductions to below the Class I standardof 0.005 mg/L. Furthermore, all reagents were injected in asafe and efficient manner, injection occurred at the shallowtarget depths, and target injection volumes were deliveredto each injection point.

Based on these conclusions, a successful treatment programwas implemented.

Site Background:Due to inclement weather, an accident occurred along Route 64 in Rochelle, Illinois involving a tanker truck. Thetanker truck was carrying over 8,500 gallons of gasoline, and approximately 534 gallons were lost on the shoulder andinto a drainage ditch. Approximately 558 tons of impacted soil was excavated from the drainage ditch and disposed ofoff-site. Additional investigation concluded that residual soil and groundwater contamination from approximately 2to 7 feet below ground surface (ft-bgs) was present adjacent to the excavated area. The soil matrix of the impactedarea consists of silty clay from 2 to 4 ft-bgs and sand from 4 to 7 ft-bgs. The depth of groundwater was estimated tobe approximately 4.5 ft-bgs. The primary contaminant of concern was benzene, which was present above the Class Igroundwater standards of 0.005 mg/L.



Site Summary: Confidential Rochelle, Illinois Project

Design & Treatment:Geo-Cleanse International, Inc. (Geo-Cleanse) was contracted to designand implement a full-scale in-situ chemical oxidation (ISCO) treatmentprogram, utilizing activated sodium persulfate (ASP). A total of 12temporary injection points were installed, with a 6-ft lateral spacing,over a 500 ft2 area. Temporary injection points were advanced viadirect push technology using a truck mounted Geoprobe. The Geoprobeadvanced the casing to 7 ft-bgs, then extracted the casing to 3.5-ft.Although there are impacts above 3.5 ft-bgs, injection directly into thisinterval was not possible due to the tight clay formation at a shallowdepth and the likelihood of short-circuiting reagents to the surface.Geo-Cleanse expected that the water table would locally moundupward around the active injection point creating contact with theshallow soil interval. A total of approximately 2,050 gallons of ASP wasapplied to the target area.


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