CIVL6618 NewHaven Treatment Technology Assessment For Hazardous Waste Management The Remedial Strategies section of your term project addresses emergency r

CIVL6618 NewHaven Treatment Technology Assessment For Hazardous Waste Management The Remedial Strategies section of your term project addresses emergency response and remedial treatment processes for the decontamination of polluted media that’s been polluted with the chemical benzene. The Transformation section of your report could serve as a guide here as natural transformation processes often present a sound basis for devising engineered treatment schemes. Material covered in Modules 5-7 is essential for this section. Biochemical reactivity is also highly relevant here. Indigenous natural organisms offer an excellent starting point for bioremediation. Although costly, recent advances in molecular biology may also be of great use here. For example, in recent years genetically modified organisms have been successfully used in bioremediation of a variety of contaminants (e.g. petroleum hydrocarbons). Use this Journal to reflect on key aspects of the remediation of various contaminated media (air, water, soil).

In an approximately 250-word entry, respond to the following:

Based on your contaminant’s physical, chemical, and biological properties identify contaminant containment strategies. Comment whether some of these strategies are applicable for emergency response.
Identify physicochemical and/or biological processes that can be used as part of remedial schemes for the treatment of contaminated, air streams, groundwater, and soil.
Compare and contrast in-situ vs. ex-situ treatment schemes.
Comment on non-technical factors (social, cultural, economic, environmental) that may influence your decision to prescribe remedial processes.

Attached within is my group members paper from a previous course pages 9 thru 15 provide a great length of detail and resources for this essay Treatment Technology Assessment for Hazardous Waste Management
CIVL 6618: Hazardous Waste Treatment
Ryan Wagner
19 December 2018
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Table of Contents
1. Introduction to Benzene ………………………………………………………………………………………. 3
2. History………………………………………………………………………………………………………………. 3
3. Physical Properties ……………………………………………………………………………………………… 3
4. Benzene in the Environment …………………………………………………………………………………. 4
5.0 Transport …………………………………………………………………………………………………………. 6
6.0 Fate of Benzene in the Environment……………………………………………………………………… 7
7.0 Contaminant Chemistry ……………………………………………………………………………………… 7
8.0 Health Effects …………………………………………………………………………………………………… 7
9.0 Regulations………………………………………………………………………………………………………. 8
10.0 Evaluation of Treatment Technologies and Alternatives …………………………………………. 9
10.1 Bioventing in Soils ………………………………………………………………………………………….. 11
10.2 Soil Vapor Extraction in Soils ……………………………………………………………………………. 12
10.3 Chemical Oxidation in Soils ……………………………………………………………………………… 13
10.4 Biopiles for Ex Situ Biological Treatment of Soils………………………………………………….. 15
11 Conclusion ………………………………………………………………………………………………………. 16
12. References ……………………………………………………………………………………………………… 17
Tables:
Table 1: Physical Characteristics of Benzene
4
Table 2: States and territories with Reported Amounts of Benzene Released to Water, Land, and
Underground Injection
4
Table 3: Remediation Treatment Technologies
10
Figures:
Figure 1: Benzene chemical structure
3
3
1. Introduction to Benzene
Benzene, also known as benzol or mineral naptha, is a colorless, sweet smelling, highly toxic,
flammable, liquid hydrocarbon (1). Benzene may be produced naturally through natural
processes such as volcanic eruptions and forest fires; and is a primary component of crude oil,
gasoline and tobacco smoke. Benzene is used to manufacture a wide variety of petrochemical
products (e.g. styrofoam, resins, phenols, cyclohexanes, and lubricants) and in industrial solvents
in paints, vanishes, lacquer thinners. Additionally, benzene is used in the pharmaceutical
industry, as well as in the manufacturing of detergents, and pesticides (3).
2. History
Michael Faraday was the first scientist to discover benzene in 1825 (10). He extracted benzene
from cylinders of compressed illuminating gas, used to illuminate buildings in London, which
had been collected from the pyrolysis of whale oil. In 1833, Eilhard Mitscherlich a German
chemist produced what he called benzin via the distillation of benzoic acid (from gum benzoin)
and calcium oxide (lime). In 1845, benzene was found in coal tar by the English chemist Charles
Mansfield. Four years later, Mansfield began the first industrial-scale production of benzene,
based on the coal-tar method. Coal tar is made by destructively distilling coal and is still a
source of benzene today. Benzene was first synthesized in a laboratory in 1870 by Pierre
Berthelot who passed acetylene through a red-hot tube.
3. Physical Properties
Benzene is a liquid aromatic hydrocarbon, volatile organic compound (VOC), with the following
chemical structure: C6 H6
Figure 1: http://www.chem.ucla.edu/~harding/IGOC/B/benzene_ring.html (4)
4
Physical characteristics are listed in Table 1 below (2):
Table 1: Physical Characteristics of Benzene
Physical State
Molecular weight
Melting Point
Boiling Point
Water solubility
Vapor pressure
soil organic sorption coefficient Koc
log octanol/water partition coefficient (log
Kow)
Colorless liquid
184. 26 g/mol
5.5 0C
80 0C
4.00 x 102 mg/L
1.00 x 10 mmHg at 176oC
8.30 x 10 mL/g
2.12
Additionally, benzene evaporates into the air very quickly and dissolves in water.
4. Benzene in the Environment
Sources of benzene released to either water or soil include domestic manufacturing and process
facilities, treated and untreated industrial waste water, leaks from underground storage tanks,
leachate from landfills and other contaminated soils sources, regulated and unregulated
hazardous waste sites (under CERCLA and RCRA), and underground injection (1). Other
sources may include accidental spills or leaks from above ground transfers or poorly maintained
infrastructure. Data collected from the USCG Emergency Response Notification System
indicated that benzene was one of the most occurring spilled non-petroleum chemicals in U.S.
waters (3).
Table 2 below tabulates all the states and territories with reported amounts of benzene released
(in lbs/year) to water, land, and underground injection from regulated facilities that produce,
process or use benzene (1).
Table 2: States and territories with Reported Amounts of Benzene Released to Water,
Land, and Underground Injection
State
Water (lbs/year)
Land (lbs/year)
Underground
Injection (lbs/year)
AK
19
375
0
AL
290
280
0
AR
66
0
0
AZ
0
9
0
CA
129
1,292
228
CO
0
10
0
5
CT
DE
FL
GA
GU
HI
IA
ID
IL
IN
KS
KY
LA
MA
MD
ME
MI
MN
MO
MP
MS
MT
NC
ND
NE
NJ
NM
NV
NY
OH
OK
OR
PA
PR
RI
SC
SD
TN
TX
UT
VA
VI
WA
WI
WV
2
6,006
41
128
1
30
1
No data
102
805
164
799
1,688
55
8
23
8
2,724
0
0
25
5
0
0
No data
443
7
0
56
67
14
8
419
7
4
6
1
63
621
750
787
0
14
0
284
0
26
0
9
0
12
0
0
2,152
4,654
259
766
1,075
26
184
0
127
131
0
0
14
15
5
1
6
150
0
0
10
730
278
41
345
0
0
250
0
280
8,326
809
26
9
95
251
393
0
0
0
0
0
0
0
0
0
14,001
231
0
122,723
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
0
5
0
0
0
0
0
0
0
0
298,595
0
0
0
0
0
0
6
WY
0
1
0
(Data is from 2004)
Estimated releases of benzene to surface water is 16,051 pounds (~7tons) from 986 domestic
manufacturing and processing facilities in 2004, accounted for about 0.2 % of the estimated total
environmental releases from facilities required to report to the TRI (1). Benzene has been
detected in groundwater samples collected at 832 of the 1,684 current and former NPL sites and
in surface water samples collected at 208 of the 1,684 sites.
Estimated release of benzene to soil is approximately 24,033 pounds (~11 metric tons) from 968
domestic manufacturing and processing facilities, accounting for about 0.3 % of the estimated
total environmental releases from facilities required to report to the TRI (1). An additional
435,000 pounds (~197 metric tons), consisting of about 6% of the total environmental emissions,
were released via underground injection.
It is noted that the state with the highest release to water was Louisiana with 1,688 lbs/year,
release to land was Texas with 8,326 lbs/year, and release via underground injection was also
Texas with 298,595 lbs/year.
5.0 Transport
Benzene may be directly released into subsurface soils and/or groundwater, or may occur
through leaching from surface spills, releases and/or discharges, or from landfills or other
contaminated sources. The influential parameters that determine the leachability include the soil
type (sandy vs clayey soils or fractured vs non-fractured rock), amount of rainfall, depth to
groundwater and seasonal fluctuations of the groundwater table, and extent of degradation (1).
Benzene is highly volatile, therefore once the contaminant is released to either a surface water
source or a near sub-surface soil source a high volatilization rate back to the atmosphere will
occur.
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6.0 Fate of Benzene in the Environment
As indicated in Table 1, the soil organic carbon sorption coefficient (Koc) is 83 mL/g, this
indicates that benzene is highly mobile in soil and highly capable of leaching into groundwater.
Once benzene has reached the groundwater table, and depending on the permeability of the soil
matrix, benzene has the capability of transporting many meters from the initial contaminated
source.
Therefore, the fate and potential impact in the environment can be averse to many sources either
through impacts directly into groundwater or through expression of groundwater into surface
water sources.
In determining the risk of either of these contaminant transport methods, it must be taken into
consideration the potential affects upon environmental sensitive areas and potential extraction or
beneficial uses (i.e. drinking water, recreational use, protection of ecosystems, agricultural uses
(stock watering and irrigation), and industrial uses).
7.0 Contaminant Chemistry
Benzene (C6H6) is an aromatic compound and the parent to which numerous other aromatic
compounds are related. Aromatic compounds consist of a large class of unsaturated chemical
compounds characterized by one or more planar rings of atoms joined by covalent bonds of two
different kinds. The unique stability of these compounds is referred to as aromaticity.
In benzene, the six carbon molecules are joined in a ring, having a planar geometry of a regular
hexagon in which all of the C – C bond distances are equal. The six π electrons circulate in a
region above and below the plane of the ring, each electron being shared by all six carbons,
which maximizes the force of attraction between the nuclei (positive) and the electrons
(negative).
8.0 Health Effects
Benzene exposure may occur through a number of pathways (5). The first being ingestion, this
may occur through drinking water from a groundwater source contaminated with the benzene.
8
The second pathway may occur through inhalation, this may occur through breathing air
contaminated with benzene vapor. And Thirdly, through dermal contact, this may occur through
skin contact if you handle gasoline or other products that may contain benzene (including
contaminated soils or sediments). The US EPA classifies benzene as carcinogenic to humans.
Long term exposure to high levels of benzene can cause leukemia and cancers of the bloodforming organs (bone marrow, lymph nodes, and spleen). Health impacts are dependent on how
much, how long, how often, and the way one is exposed. Young children, the elderly, and
people with on-going health problems are more at risk for negative health impacts from benzene
exposure. Breathing high levels of benzene may result in a rapid heart rate, dizziness, tremors,
headaches, and drowsiness. Breathing high levels of benzene for long periods of time may cause
serious problems with the production of blood. Benzene causes harmful effects on the bone
marrow and can cause a decrease in red blood cells, leading to anemia. Additionally, it can also
cause excessive bleeding and affect the immune system. Drinking high concentrations of
benzene can cause an irritated stomach, vomiting, rapid heart rate, dizziness, convulsions, and
sleepiness.
9.0 Regulations
Many chemicals are listed as toxic substances for specific regulatory purposes (2). Benzene is
designated a priority pollutant under the Clean Water Act. Listed as a hazardous substance,
designated under the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA). Designated as a listed chemical under Appendix IX of 40 CFR Part 264 (7). The
regulation requires that benzene is monitored in groundwater monitoring wells surrounding
Resource Conservation and Recovery Act (RCRA) land based hazardous waste disposal units.
The monitoring must take place when groundwater contamination is first detected, and then
again once per year. Additionally, benzene is designated a hazardous air pollutant under the
1991 Clean Air Act Amendment.
In 1974, Congress passed the Safe Drinking Water Act (8). This law required the US EPA to
determine the level of contaminants in drinking water at which no adverse health effects are
likely to occur. These goals non-enforceable health goals, based solely on possible health risks
and exposure over a lifetime with an adequate margin of safety, are called maximum
contaminant level goals (MCLG).
9
MCLG for benzene is zero (8). The EPA set this level of protection based on the best available
science to prevent potential health problems. Additionally, the EPA has set an enforceable
regulation for benzene, referred to as the maximum contamination level (MCL), at 0.005 mg/L
or 5 ppb. MCLs are set as close to the health goals as possible, considering cost, benefits and the
ability of public water systems to detect and remove contaminants using suitable treatment
technologies.
The Act also requires the EPA to conduct a Six Year Review of the Drinking Water Standards.
The reviews have indicated that EPA still determines that the level of 0.005 mg/L or 5 ppb are
still protective to human health (8).
Additionally, individual states may set more stringent drinking water MCLGs and MCLs for
benzene than EPA.
In comparison to the EPA drinking water guideline, the World Health Organization (WHO) has
determined that for the protection of human health a safe drinking water level of 0.001 mg/L is
suitable (9).
10.0 Evaluation of Treatment Technologies and Alternatives
In determining all remediation technologies, one must take into consideration the following
factors: contaminate of concern, concentration levels, geological (i.e. sandy clay vs fractured
basalt) and geochemical factors, required clean up levels, appropriate technology, cost of
remediation, impacts to human health and sensitive environmental receptors, time to remediate
the contaminated site, and regulatory requirements (11).
Ex situ remediation includes techniques such as landfarming, biopiling, and processing by
bioreactors along with thermal, chemical, and physical processes. These processes are suitable
for contaminants such as PAHs, BTEX, phenolic compounds, cyanides, and PCBs, to name a
few. Even though ex situ remediation is a more efficient remediation technique, and less
technical technique, the costs are generally higher than in situ remediation due to the remediation
processes and exaction, transport and disposal of the waste (11).
In situ remediation techniques include bioventing, biosparging and phytoremediation along with
physical, chemical and thermal processes. These processes are suitable for contaminants such as
10
free product petroleum, PAHs, BTEX, TCEs, and non-chlorinated solvents. In situ monitoring
techniques may be less costly than ex situ due to lack of excavation and transport cost, but may
be more costly due to costs associated with advanced site characterization, additional monitoring
and extraction wells installed, pilot trials, installation of remedial engineering technology and
equipment set up to extract, treat and dispose of soil vapor, and the free phase and dissolved
phase liquid hydrocarbon contaminants, and on-going monitoring to determine the reduction of
contaminants, and any potential on-going natural attenuation of the contaminants of the
contaminants after remedial treatment (11).
Table 3 below outlines some (but not all) remediation technologies applicable for Benzene (12).
The table is divided into remediation treatment techniques for soil, sediment and sludge, and for
groundwater, surface water and leachate. Additionally, the table gives a description of the
development status, use rating, and strategy for the specific technology.
Table 3: Remediation Treatment Technologies (12).
Technology
Development Status Use Rating
Soil, Sediment and Sludge
In Situ Biological Treatment
Bioventing
Full
Wide
Enhanced
Full
Wide
Biodegradation
Phytoremediation
Pilot
Limited
In Situ Physical/Chemical Treatment
Chemical Oxidation
Full
Limited
Soil Flushing
Pilot
Limited
Soil Vapor Extraction Full
Wide
Ex Situ Biological Treatment (Assuming Excavation)
Biopiles
Full
Wide
Composting
Full
Wide
Landfarming
Full
Wide
Ex Situ Physical / Chemical Treatment (Assuming Excavation)
Chemical Extraction Full
Limited
Chemical Reduction / Full
Limited
Oxidation
Soil Washing
Full
Limited
Ex Situ Thermal Treatment (Assuming Excavation)
Pyrolysis
Full
Limited
Other Treatment
Excavation and OffN/A
Wide
Site Disposal
Technology Strategy
Destruct
Destruct
Destruct
Extract
Extract
Extract
Destruct
Destruct
Destruct
Extract / Destruct
Destruct
Extract
Destruct
Extract/Immobilize
11
Groundwater, Surface Water and Leachate
In Situ Biological Treatment
Enhanced
Full
Limited
Biodegradation
Natural Attenuation
Full
Limited
Phytoremediation
Full
Limited
In Situ Physical / Chemical Treatment
Air Sparging
Full
Limited
Bioslurping
Full
Limited
Chemical Oxidation
Full
Limited
Dual Phase
Full
Limited
Extraction
In Well Air Stripping Full
Limited
Ex Situ Biological Treatment (Assuming Pumping)
Bioreactors
Full
Limited
Ex Situ Physical / Chemical Treatment (Assuming Pumping)
Advanced Oxidation Full
Limited
Processes
Air Stripping
Full
Wide
Granulated Activated Full
Wide
Carbon (GAC) /
Liquid Phase Carbon
Adsorption
Ground Water
Full
Limited
Pumping
Destruct
Destruct
Extract
Extract
Destruct
Destruct
Extract
Extract
Destruct
Destruct
Extract
Extract
Extract
10.1 Bioventing in Soils
Bioventing is a new technology in which oxygen is delivered to contaminated unsaturated soil by
forced air movement (either extraction or injection of air) to increase oxygen concentrations that
stimulates the natural in situ biodegradation of any aerobically degradable compounds in soil by
providing oxygen to existing soil microorganisms (12). In contrast to soil vapor vacuum
extraction, bioventing uses low air flow rates to provide only enough oxygen to sustain microbial
activity. Oxygen is most commonly supplied through direct air injection into residual
contamination in soil. In addition to degradation of adsorbed fuel residuals, volatile compounds
are biodegraded as vapors move slowly through biologically active soil. Regulatory acceptance
of this technology has been obtained in 30 states and in all 10 EPA regions, and use of this
technology in the private sector is growing rapidly. Bioventing is a medium to long-term
technology. Clean-up ranges from a few months to several years. Bioventing techniques have
12
been successfully used to remediate soils contaminated by petroleum hydrocarbons,
nonchlorinated solvents, some pesticides, wood preservatives, and other organic chemicals.
Factors that may limit the applicability and effectiveness of the process include (12):
•
The water table is within several feet of the surface, saturated soil lenses, or low
permeability soils reduce bioventing performance.
•
Vapors can build up in basements within the radius of influence of air injection wells.
This problem can be resolved by extracting air near the structure of concern.
•
Monitoring of off-gases at the soil surface may be required.
•
Low temperatures may slow remediation, although successful remediation has been
demonstrated in extremely cold weather climates.
Key cost factors associated with bioventing in soil include (12):
•
Surface area of the contaminant: this impacts the number of injection wells that are
needed to be installed. The number of wells required to be installed (and cost) increases
with the surface area.
•
Soil type: soil types containing sand and gravel produced significantly lower costs by
reducing the number of injection/extraction wells that needed to be installed.
10.2 Soil Vapor Extraction in Soils
Soil vapor extraction (SVE) is an in situ unsaturated (vadose) zone soil…
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