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Ozone-Peroxide
Advanced Oxidation Water Treatment System for Treatment of
Chlorinated Solvents and 1,4-Dioxane
Dr.
Reid H. Bowman, Chief
Technical Officer, Applied Process Technology, Inc., 3333
Vincent Road, Suite 222, Pleasant Hill, CA 94523, Tel:
925-977-1811, Fax: 925-977-1818
Philip Miller, England
Geosystem, Inc., 15375 Barranca Parkway, Suite F-106,
Irvine, CA 92618-2207, Tel: 949-453-8085, Fax:
949-453-0733
Michael Purchase, Orion
Environmental, Inc., 3450 E. Spring St., Suite 212, Long
Beach, CA 90806, Tel: 562-988-2755 Fax:
562-988-2759
Randy Schoellerman, San
Gabriel Basin Water Quality Authority, 858 Oak Park Road,
Suite 200, Covina, CA 91724, Tel: 626-859-777, ext. 26,
Fax: 626-859-7788
A
suspected carcinogen, 1,4-dioxane is an industrial solvent
and an acid scavenger frequently added to chlorinated
solvents to neutralize hydrochloric acid.
Common analytical methods used in groundwater
quality investigations, such as EPA Method 8260, either do
not include 1,4-dioxane or achieve relatively high
detection levels, on the order of 100 µg/l.
Detection of 1,4-dioxane to 3 µg/l
requires EPA Method 8270M.
The State of California recently adopted a drinking
water “action level” of 3 µg/l,
prompting more intensive monitoring for 1,4-dioxane in
groundwater. As
a result of this monitoring, 1,4-dioxane has been
discovered in groundwater wells where pump and treat
remediation systems are in place to remove chlorinated
solvents. Commonly used groundwater treatment
technologies, such as air stripping and liquid-phase
granular activated carbon (LGAC), have been shown to be
ineffective in removing 1,4-dioxane.
A line pressure advanced oxidation process (AOP)
using ozone and hydrogen peroxide has been shown to
effectively remove 1,4-dioxane to below the 3 µg/l. This AOP
technology has been integrated into existing remediation
systems, both air stripping and LGAC, as a pretreatment
for the removal of 1,4-dioxane.
In addition to removing 1,4-dioxane to below 3 µg/l,
the concentrations of most of the other chlorinated
solvents present were significantly reduced.
The concentration of 1,4-dioxane treated ranged
from 7 to 600 µg/l.
The scalability of line pressure advanced oxidation
of 1,4-dioxane and chlorinated solvents has been
demonstrated from pilot tests of 10 GPM to commercial
installations of 1,000 GPM.
Implementation
of an In Situ Chemical
Oxidation Program for Remediation of Saturated Zone
Petroleum Hydrocarbons at the Navy Exchange Service
Station Naval Air Station, Brunswick, Maine
Alexander
C. Easterday, EA Engineering, Science, and Technology,
175 Middlesex Turnpike, 3rd Floor, Bedford, MA
01730, Tel: 781-275-8846
Curtis J. Varner, EA Engineering, Science, and
Technology, 3 Washington Center, Newburgh, NY 12550, Tel:
845-565-8100
A
full-scale in situ
chemical oxidation program utilizing hydrogen peroxide (H2O2)
to remediate residual dissolved-phase and sorbed-phase
petroleum hydrocarbons was applied at the Navy Exchange
Service Station, Naval Air Station, Brunswick, Maine.
In situ chemical oxidation was selected as a final remedial
technology to achieve site closure following several years
of active soil vapor extraction/air sparging operations,
which successfully treated vadose zone contamination and
significantly reduced saturated zone petroleum hydrocarbon
concentrations. In situ chemical oxidation was utilized to mitigate
residual saturated zone petroleum hydrocarbons that were
found to be recalcitrant to ongoing soil vapor
extraction/air sparging operations.
To assess
the site-specific effectiveness of in
situ chemical oxidation and to provide necessary data
for design of the full-scale in situ chemical oxidation injection program, bench-scale testing
was completed using ground-water and saturated zone soil
samples collected from the remedial target area.
The bench-scale tests evaluated percent oxidation
of benzene, toluene, ethylbenzene, and total xylenes;
methyl tertiary-butyl ether; and total petroleum
hydrocarbons against applied doses of hydrogen peroxide
and ferrous-iron chelating agent solutions.
Bench-scale testing and in
situ chemical oxidation injection procedures were
completed by ISOTEC Inc., of West Windsor, New Jersey,
under subcontract to EA.
The
full-scale in situ
chemical oxidation injection program was designed and
implemented using the bench-scale testing results.
To evaluate the effectiveness of the full-scale in situ chemical oxidation program, ground-water and saturated zone
soil samples were collected prior to and following each
injection event.
This
presentation will detail the results of the bench-scale
testing and full-scale in
situ chemical oxidation program with an emphasis on
the correlation of the bench-scale testing to the
full-scale in situ
chemical oxidation effectiveness.
The presentation will also discuss the overall
effectiveness of the in
situ chemical oxidation remedial program for reducing
dissolved-phase and sorbed-phase petroleum hydrocarbon
concentrations as required to achieve conditions necessary
for proceeding to site closure.
Cost
Effective Application of Modified Fenton’s Reagent at an
Operational Dry Cleaners Site
Prasad
K. Kakarla, In Situ Oxidative Technologies, Inc., 51
Everett Drive, A-10, West Windsor, NJ 08550, Tel:
609-275-8500, Fax: 609-275-9608, Email: prasad.kakarla@isotec-online.com
Richard S. Greenberg, In Situ Oxidative
Technologies, Inc., 51 Everett Drive, A-10, West Windsor,
NJ 08550, Tel: 609-275-8500, Fax: 609-275-9608, Email: richard.greenberg@ewma.com
Advanced
oxidation techniques based on Fenton’s chemistry are
increasingly surpassing traditional remediation treatments
with respect to cost effectiveness, expediency, variety of
contaminants mineralized, and the innocuous nature of the
end products. Despite
its benefits, the field application of Fenton’s Reagent
in its traditional form has historically been hindered by
the instability of oxidizing and catalytic reagents when
introduced into the subsurface, and the impracticality of
lowering the native pH to acidic conditions.
Therefore, a modified Fenton’s reagent consisting
of chelated iron catalyst and stabilized peroxide capable
of functioning in the neutral pH range was developed by
In-Situ Oxidative Technologies, Inc. (ISOTECSM).
The modified Fenton’s reagent delays formation of
reactive hydroxyl radicals, allowing the oxidizing agent
to thoroughly disperse in the subsurface first.
ISOTECSM implemented its patented
process, which incorporates the modified reagent, to
remediate a contaminated groundwater plume caused by an
operational dry cleaners located in northeast Florida. The
ground water was contaminated with up to 38 µg/l of
Trichloroethene (TCE) and 54 µg/l of Tetrachloroethene (PCE)
spread over an approximately 8,500-sq. ft area. The low
chlorinated solvent concentrations render conventional
treatment techniques more costly and less effective,
despite the high capital, operation, and maintenance costs
involved. Initially,
a laboratory bench scale and in-situ field experiments
were performed to ascertain the subsurface
characteristics, treatment stoichiometry, and process
conditions. The
results of the laboratory bench scale indicated a 100%
reduction in total VOCs found in the ground water sample.
A small portion of the groundwater plume was
utilized for a field pilot program, which involved a 4-day
injection event. The
pilot program yielded positive results; the concentrations
of all VOC compounds in the treated area measured below
Florida Department of Environmental Protection (FDEP)
regulatory guidelines.
In the full-scale treatment program that followed,
the majority of the plume was treated and all contaminant
concentrations were reduced to below applicable FDEP
groundwater quality criteria (3 µg/l for both TCE and PCE)
after three two-week treatments over a six-month
timeframe. Closure of the site is expected in the summer of 2002, after
8 quarters of FDEP required post-treatment groundwater
monitoring. The
entire treatment program was completed for an approximate
cost of $18.00 per cubic yard of soil.
The
Thermodynamics of Sodium Permanganate Oxidative Reactions
Brenda
Veronda, Carus Chemical Company, 315 5th
St., Peru, IL 61354,
Tel: 815-224-6557, Fax:
815-224-6663
Ken Pisarczyk, Carus Chemical Company, 315 5th
St., Peru, IL 61354,
Tel: 815-224-6503, Fax:
815-224-6663
Erik Pedersen, Carus Chemical Company, 1500 8th
St., LaSalle, IL 61301,
Tel: 815-224-6869, Fax:
815-224-6841
According
to the United States Environmental Protection Agency (USEPA),
a significant number of the hazardous waste sites in the
United States have contaminated groundwater.
Some of the most common contaminants are
chlorinated organic solvents such as trichloroethylene (TCE)
and perchloroethylene (PCE).
In-situ (ISCO) and ex-situ chemical oxidation
techniques and technologies have been developed to quickly
and effectively oxidize these types of chlorinated
contaminants. The
key reacting element in these remediation techniques is
the oxidant, and knowledge of how the oxidant reacts and
the consequences of its reactions are critical factors
that can affect the successful completion of a remediation
project.
The use
of permanganate ( MnO4- ) as the
oxidant for in-situ or ex-situ chemical oxidation is
characterized by fast reaction rates that result in the
complete mineralization of TCE and PCE into carbon
dioxide, water and chloride salts.
Sodium and potassium permanganate are strong
oxidizing reagents, and the reactions need to be
thoroughly understood and controlled in order to achieve
optimum oxidation results.
The kinetics – or rate at which permanganate
reactions occur, and the thermodynamics - amount of heat
released during a reaction, are important safety factors
that depend directly upon the concentration of the
oxidant.
Data will
be presented illustrating the effects of oxidant
concentration on the amount of heat released during these
reactions. In
addition to the reactions of interest, the presentation
will also examine the reactions between the oxidant and
other common reducing agents present at remediation sites. How oxidant concentrations radically alter the reaction
characteristics and directly affect the hazardous
characteristics and conditions that surround the product
will be discussed.
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