tws remediation-2
TRANSCRIPT
TWS REMEDIATION
Physical and Chemical Remediation in New Jersey
Stockton University
TJ Denbleyker, Sara Chojna, William Hale
Author Note
This project was done in conjunction with Stockton University’s Remediation and Biotechnology course, ENVL 4446, taught by Dr. Tait Chirenje.
In Honor of Toni Sr.
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Abstract
Our company’s goal is to implement optimal remediation techniques for the soil and
groundwater contamination issues specific to New Jersey. Unfortunately, Trichloroethylene
(TCE), Tetrachloroethylene (PCE), benzene, toluene, ethylbenzene, xylene (BTEX), and Methyl
tert-butyl ether (MTBE) are not only dangerous to human health but remain as the most
prevalent contaminants in New Jersey. Our remediation services are a necessity in protecting
both human health and groundwater resources from these chemicals. Due to New Jersey’s
steadily rising population redevelopment and property transfers are growing and will continue to
do so making our services a much needed commodity. Whether the project requires the
remediation of soil or groundwater from leaking underground storage tanks, dry cleaning
services, or auto body shops we have highly trained professionals who can utilize a variety of
physical and chemical remediation techniques to meet or surpass the required cleanup
standards.
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Table of Contents
Abstract Page 1
Table of Contents Page 2
Environmental Business Prospects Page 3
Contamination in New Jersey Page 3-4
Site Characterization Pages 4-5
Physical Remediation Techniques Pages 5-9
- Excavation Page 5
- Pump and Treat Pages 5-6
- Soil Vapor Extraction and Air Sparging Pages 6-7
- Capping Pages 7-8
- Soil Washing Page 9
Chemical Remediation Techniques Pages 9-11
- Chemical Oxidation Page 10
- Critical Fluid Extraction Page 10
- Permeable Reactive Barrier Page 10-11
Conclusion Page 11
References Page 12
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Environmental Business Prospects
The remediation field in New Jersey is experiencing a wide variety of favorable factors
that will make the longevity and success of a remediation company certain. New Jersey has a
long past of industrial and commercial environmental pollution, having nearly a century’s worth
of legacy pollution to attest to. With the extensive pollution from New Jersey’s industrialized
past creating hot spots of contamination in conjunction with land reaching an all-time premium
the work for remediation firms is bountiful and alone could constitute a reason to get into the
mix. As the economy continues to recover remediation and redevelopment projects are
substantially increasing. With New Jersey’s growing population and the limited amount of
existing land in the state, brownfield remediation projects and property transfers will continue to
grow for quite a long time. Remediation services are a necessity in protecting human health and
groundwater resources and with New Jersey’s long history of legacy pollution and its need of
redevelopment and property transfers due to population increase and limited land the time to
enter into to the remediation field has never been better.
Contamination in New Jersey
Many counties in New Jersey have contaminated soil and groundwater with a large
majority of the contamination coming from gas stations, dry cleaners, scrap metal yards, and
auto repair shops. Gas stations contain underground storage tanks (USTs) that may leak
petroleum products like benzene, toluene, ethylbenzene, and xylene (abbreviated as BTEX),
while also leaking additives like Methyl tert-butyl ether (MTBE). The contamination of such
chemicals is due to the improper maintenance or deterioration of USTs over time. In New Jersey
alone, there are currently 5,936 active UST remediation’s and an additional 1,126 known or
suspected UST sites yet to begin the remediation process (NJDEP). In addition, many gas
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stations are also auto repair shops and spilling antifreeze and oil products, in conjunction with
other potentially hazardous materials, is a fairly common occurrence. Lead, oil, and grease can
leak when radiators are flushed but the most prevalent pollutant in New Jersey according to
Goodguide scorecard report is Trichloroethylene (TCE), a chlorinated hydrocarbon. Used as an
industrial solvent it has found use in multiple industries with its greatest use as a degreaser of
metal parts at auto body shops and metal scrap yards. TCE amongst other VOCs and SVOCs are
released accidentally or improperly and eventually find their way into surface and groundwater
and site remediation is needed to protect and preserve these essential resources. New Jersey
contains a substantial number of dry cleaning businesses, and the improper disposal of hazardous
chlorinated solvents such as TCE and PCE is common cause for the need to conduct site
remediation as both chemicals are found to be probable carcinogens and are regulated under EPA
guidelines.
Site Characterization
Often times the first and most important step in producing a proper contaminated site
remediation strategy is site characterization. The site characterization process consists of the
collection and assessment of data representing the contaminant type and the distribution of the
identified contaminants on property. To properly and adequately characterize a site the
collection of data must include the site geology, site hydrology, and site contaminants, with a
specific focus on the type, concentration, and distribution. Site characterization is typically
carried out in a multiple phase process, starting with a simple preliminary assessment called a
phase I and ending with a full, detailed site investigation that takes into account all of the factors
mentioned above. This work will be subcontracted out to the lowest bidders and based on the
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results of the site investigation and characterization a remediation method that is most applicable
to the site will be chosen and implemented to clean the property to acceptable levels.
Physical Remediation Techniques
Excavation
One of the most simple and straightforward physical remediation techniques our
company will use is excavation. The process involves the removal of the contaminated soils with
the use of standard construction equipment such as backhoes and excavator trackhoes for either
ex situ (above-ground) treatment or disposal via a hazardous waste landfill. Excavation is a
commonly used means of remediating a site and is typically used when other in situ cleanup
methods are either too expensive or too time consuming to perform. The process is highly
effective in remediating the area as it removes the entire zone of contamination, but its usability
is largely dictated by contaminant depth and site accessibility. Excavation in general is a
relatively quick process but the time span depends greatly on the specifics of the site, with
excavation for small quantities of contaminated soil being a very cost-effective approach. The
costs of using an excavation technique to remediate a site will come from renting both heavy
machinery and a licensed operator, based on nationwide averages hourly rates range from $70-90
dollars an hour and contracts can be worked out for sites that require extended use.
Pump & Treat
Our company will also utilize a pump and treat system, a method which consists of
installing one or more wells to extract contaminated groundwater from the site. The
groundwater is pumped from the subsurface via the drilled extraction wells and transported
either directly into a treatment system or storage tanks. Pump and treat systems are a physical
means of removing contamination but will always be used in conjunction with another treatment
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method to treat the extracted groundwater. With a large portion of New Jersey’s contaminants
consisting of VOCs including TCE and PCE the use of a Granular Activated Carbon (GAC)
system can be used. GAC systems used alongside pump and treat systems have a tremendously
high level of efficiency in treating VOCs such as BTEX, TCE and PCE amongst other synthetic
organic compounds and disinfectants at nearly 99.99% (6). The cost of purchasing a GAC
system depends entirely on the size needed, but in many cases renting a unit will be sufficient
and the pricing can be negotiated based on the the time length required. Once a system is in
place it can run with relatively little human interaction, requiring periodic monitoring and
maintenance.
Soil Vapor Extraction and Air Sparging
Soil Vapor Extraction (SVE) and Air Sparging are two physical remediation techniques
that our company will use to remediate contaminants from the subsurface soil and
groundwater. SVE involves the drilling of one or more wells into the contaminated soil,
followed by the attachment of a vacuum pump called a blower which will create a vacuum under
the subsurface. The vacuum created by the pump pulls both air and vapors through the wells
towards the surface where they are collected for treatment. This process requires a minimum
depth of at least three feet otherwise the creation of a vacuum will not be possible. In some
instances the use of a tarp to cover the surface contamination zone will be needed so as to
prevent clean air from being sucked downward, reducing efficiency and increasing the length of
time required. The collected gases are typically run through a granular activated carbon system
referred to as a GAC, where they pollutants are deposited in the activated carbon and clean air is
released back out into the atmosphere. The air sparging process begins in similar fashion, but
instead the one or more wells will act as injection ports and will be sunk directly into the ground
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water soaked soil underneath of the water table. With the use of an air compressor air is
forcefully pumped into the ground, as the air bubbles permeate through the groundwater they
carry the contaminant vapors upwards into the soil above the water table allowing an SVE
system to be used to collect the air and contaminant vapors for treatment. Both air sparging and
SVE are useful in remediating chemicals that readily evaporate, making VOC’s perfect
contaminants for these remediation techniques. What makes these techniques so incredibly
useful is its ability to be used underneath existing buildings allowing hard to reach contaminants
to be remediated with minimal disturbance to the surface of the site. The time length required to
achieve cleanup standards depends greatly on the type and moisture content of the soil. When
soils contain high clay contents or have high moisture content vapors travel at a much slower
pace increasing the project length. SVE and air sparging are tried and proven remediation
techniques having been selected for implementation at approximately 365 registered Superfund
nationwide (7).
Capping
Capping will also be another physical remediation method that can be implemented by
our company. Capping involves the placement of a cover over top of the contaminated
soil. These covers are commonly referred to as “caps” thus the name capping is used to describe
the remediation technique. Caps do not degrade, destroy or remove soil contaminants but instead
isolate and contain them to prevent further spreading with the main goal of preventing human
and wildlife interaction with the hazardous material. The type of cap used depends greatly on
the type of contaminant and the characteristics of the site, ranging from concrete and asphalt to
use of a clay or vegetative layer. Caps work well with containing most VOC’s, SVOC’s, X-
SVOC’s, and heavy metals. Caps work moderately well with X-VOC’s, radionuclides, and other
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inorganic compounds. Cap depth plays an important part in how effective the implemented cap
will function; the deeper the cap is placed the better it will perform as a barrier. The sediment
type the cap is placed on is another factor in its effectiveness; high silt soils have the highest
performance while granular soils with large particle sizes perform the worst. Caps can be a costly
method of remediation as the material costs are high in addition to usually having to cover a
large area to properly contain the hazardous materials. The work involved to create the cap can
be intensive but if properly installed and maintained a cap can be a highly effective tool for
treatment.
Soil Washing
Soil washing is another physical remediation technique that will be used by our
company. Soil washing is a technology that uses liquids in conjunction with a mechanical
process to scrub contaminants from polluted soil. Silt and clay particles in soil have the
tendency to bind to contaminants and in return these silt and clay particles bind to larger sand
and gravel. The soil washing process begins with the excavation and relocation of the
contaminated soils into a staging area. The soil is then fed into the soil washing equipment
where larger sized rocks and and boulders are removed. The remaining soil enters into a soil
scrubbing machine where a liquid is used, typically water but additional additives such as
detergents are possible, is mixed with the soil to cleanse away the contaminants. The wash water
is then drained away and clean water is used to rinse the soil again. The costs typically range
from $150-250 per cubic meter of soil and the equipment needed can be rented and pricing can
be worked out based on how long the heavy equipment is needed.
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Chemical Remediation Techniques
Chemical Oxidation
The first chemical remediation technique our company will use is called in situ Hydrogen
Peroxide Remediation. This technique can be used to remove TCE, MTBE, and BTEX. For the
removal of MTBE and BTEX, a warehousing facility in Union County, NJ had used the
technique to clean the groundwater in unsorted rocks and sand. While the total cost of the
demonstration turned out to be $220K, post-treatment samples indicated that both MTBE and
BTx were below detection limits. In addition to removing BTEX and MTBE, this technique has
proven useful to remove TCE from clay backfill types of soil. One such example was at
Anniston Army Depot, Anniston, AL, where the remedial project’s area was about 2 acres with
over 43,125 cubic yards of contaminated soil. After 4 months and more than $5.7M later, soils
that were over 1,760mg/kg in TCE concentration were reduced to below detection.
Our company’s second technique, in situ chemical oxidation with Potassium Permanganate
(KMnO₄), will address contamination issues with TCE and PCE in groundwater. This technique
has been shown to be effective in many instances. One such case was on the Canadian Forces
Base Borden located in Ontario, Canada. The soil type at that location was sand. The source zone
in this area had contained an average of 1,200 mg/kg TCE and 6,700 mg/kkg PCE. While the
price for such a process was low (a mere $45K), preliminarily analysis indicated that there was a
99% reduction in peak concentration for TCE and PCE.
Critical Fluid Extraction
The third chemical remediation technique the company will use to address the
contamination of organic compounds and petroleum hydrocarbons in soil is called Critical Fluid
Extraction. Organic compounds, like TCE and PCE, have shown to be responsive to extraction
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from soils (higher in sandy and gravelly soils than in silt) and sludges with a technique utilizing
liquefied gas. Clay-Sand soils have also shown responsive, using this technique, when extracting
petroleum hydrocarbons (7). Usually the liquified gases used are carbon dioxide, propane,
butane, or alcohol (on rare occasions). The method begins in this way: High pressure and
moderate temperatures compress the specified gases to a fluid state. Extraction begins with the
addition of hazardous waste to a vessel containing a critical fluid. Organic compounds move to
the top of the vessel, with the critical fluid, and are pumped to a different vessel. In this vessel,
the temperature and pressure are decreased causing the contaminants to volatilize from the
critical fluid. At that point, the concentrated organics are recovered while the fluid is just
recycled. While this is a higher cost remediation technique, volatile and semivolatile organics in
liquid and semi-solid wastes have been removed with 99.9 percent extraction efficiency in the
laboratory and are quite effective when implemented in the field (4).
Permeable Reactive Barriers
The fourth technique our company will use to address TCE and PCE groundwater
contamination will be passive (requiring lower operational and maintenance than pump and treat)
in situ Permeable Reactive Barriers (PRBs). PRBs remediate contaminated groundwater that
passes through a reactive zone where contaminants like TCE and PCE are either immobilized or
chemically converted to a more desirable state (8). Most applications of this use zero-valent iron
(ZVI) to treat chlorinated solvents. It is important to note that a PRB is a barrier to contaminants,
but not to groundwater flow. The technique is advantageous for site redevelopment use and the
long-term performance of such a technique as shown to be reliable.
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Conclusion
The formation of our New Jersey based remediation company is occurring at a time
where potential business is at an all-time high. With New Jersey’s history of pollution and the
increase in redevelopment activity the need for site remediation services is steadily
increasing. Our company will offer multiple remediation techniques that will allow us to clean a
wide variety of contaminated sites. Physical remediation methods will include excavation, pump
and treat, soil vapor extraction and air sparging, capping and soil washing. In addition, our
company will utilize chemical remediation methods that include chemical oxidation, critical fluid
extraction and permeable reactive barriers. Based on the results of the site investigations an
appropriate physical or chemical remediation method will be chosen to meet cleanup standards
and achieve optimal results.
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References
1. C.L. Ho, M.A-A. Shebl, and R.J. Watts, Development of an injection system for in situ
catalyzed peroxide remediation of contaminated soil. Hazardous Waste & Hazardous
Materials 12:15-25; 1995.
2. D.D. Gates, R.L. Siegrist, In-situ chemical oxidation of trichloroethylene using hydrogen
peroxide. Journal of Environmental Engineering. 121(9):639-44; 1994.
3. E.K. Nyer, Groundwater treatment technology 2nd ed. New York, NY: Van Nostrand
Reinhold; 1992.
4. R. Bellandi (ed), Innovative engineering technologies for hazardous waste remediation.
New York: Van Nostrand Reinhold; 1995.
5. "Drinking Water Treatment Technology Unit Cost Models and Overview of
Technologies." EPA. Environmental Protection Agency, n.d. Web. 27 Mar. 2016.
6. A Citizen's Guide to Soil Vapor Extraction and Air Sparging. Washington, D.C.: U.S.
Environmental Protection Agency, Office of Solid Waste and Emergency Response,
2001. Www.EPA.gov. Environmental Protection Agency, Sept. 2012. Web.
7. Reis, E., Lodolo, A., & Miertus, S. (2007). Interstate Technology and Regulatory
Cooperation Work Group Permeable Reactive Barriers Work Team. Retrieved March 27,
2016
8. United States, Environmental Council of the States, Interstate Technology Regulatory
Corporation. (2009, September). Regulatory Guidance for Permeable Reactive Barriers
Designed to Remediate Inorganic and Radionuclide Contamination. Retrieved March 27,
2016, from http://www.itrcweb.org/Guidance/GetDocument?documentID=67