CARUS REMEDIATION TECHNOLOGIES
In Situ Chemical Oxidation
(ISCO)
Prepared by: Dr. Ing. Lorenzo Sacchetti
CRT Director Europe, Middle East and Africa
[email protected]
The Science
The Basic Premise:
Inject an oxidizing agent into a contaminated zone in
order to chemically break the carbon bond converting the
contaminant from a toxic compound to naturally occurring
non- hazardous compounds.
What is In Situ Chemical Oxidation?
Distribution
Reagent load
Success is enough oxidant (reducer)
in contact with the contaminant for a long
enough period of time to react effectively
Reagent persistence
Contaminant Destruction
What is In Situ Chemical Oxidation?
The art of achieving contact between
the oxidizing agent and the
contaminant
•Choosing the correct reagent
•Choosing the correct delivery mechanism
•Understanding the site specific oxidant demand
•Creating contact
What is In Situ Chemical Oxidation?
In its simplest sense ISCO remains a contact process
requiring the oxidant to physically contact the
contaminant:
Contact = Reaction (hopefully)
Success ( potentially… )
No Contact = No Reaction
Failure ( definitely! )
Contact is facilitated by a variety of methods and
techniques
Where to apply ISCO ISCR
GW Flow
Dissolved Plume Area 10% Mass
Core Plume Area 10% Mass
Source Area 80% Mass
75% Plume Size
20% Plume Size
5% Plume Size
Bioremediation, Natural Attenuation,
ISCO-ISCR (speed only)
ISCO - ISCR, BioRemediation,
Pump & Treat
Dig and Haul, Thermal,
ISCO - ISCR
The Oxidants
•
•
.
•
•
Permanganate RemOx® S and RemOx® L
MnO4- + 4H+ + 3 e- → MnO2 + 2 H2O
Fenton
H2O2 + 2H+ + 2e- → 2 H2O
2 ·OH + 2H+ + 2e- → 2 H2O
·HO2 + 2H+ + 2e- → 2 H2O
·O2- + 4H+ + 3e- → 2 H2OHO2- + H2O + 2e- → 3 OH- Ozone
O3 + 2H+ + 2 e - → O2 + H2O
2 O3 + 3H2O2 → 4 O2 + 2 ·OH + 2 H2O
Persulphate OBC™
S2O22- + 2 e - → 2 SO4
·SO4- + e - → SO4
1.7 V (permanganate ion)
1.8 V (hydrogen peroxide)
2.8 V (hydroxyl radical)
1.7 V (perhydroxyl radical)
2.4 V (superoxide radical)
0.88 V (hydroperoxide anion)
2.1 V (ozone)
2.8 V (hydroxyl radical)
2- 2.1 V (persulphate)
2- 2.6 V (sulphate radical)
CoCs and Oxidants - I
Hydrogen Peroxide
Oxidant and Activation
Technique
Persulfate
Permanganate
Chelated iron
None*
Iron/acid
Alkaline pH
Iron
Chelated iron
None
Peroxide
Light hydrocarbon fuels1
Fair
Good
Good
Good
Excellent
Excellent
Excellent
Good
Excellent
Heavy hydrocarbon fuels2
Poor
Fair
Fair
Fair
Good
Poor
Fair
Poor
Good
Creosote, coal tar, MGP
residuals, other PAHs
Good
Good
Good
Good
Good
Fair
Fair
Poor
Good
PCBs or PBBs3
N/R**
Fair
Poor
Fair
Fair
Poor
Poor
N/R
Fair
N/R
Fair
Poor
Fair
Fair
Poor
Poor
N/R
Fair
Common contaminant mixtures
.
Dioxins or furans
Common specific fuel contaminants and breakdown products
Benzene
N/R
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Toluene
Good
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Ethylbenzene
Good
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Xylenes (o-, p- or m-)
Good
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Methyl-tertbutylether
(MTBE)
Poor
Good
Good
Good
Excellent
Excellent
Excellent
Excellent
Excellent
Tert-butyl alcohol (TBA)
N/R
Fair
Fair
Fair
Good
Fair
Fair
Poor
Good
CoCs and Oxidants - II
Hydrogen Peroxide
Oxidant and Activation
Technique
Permanganate
Chelated iron
None*
Persulfate
Iron/acid
Alkaline pH
Iron
Chelated iron
None
Peroxide
Common chlorinated solvents, stabilizers and their breakdown products
Tetrachloroethene (PCE)
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Trichloroethene (TCE)
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
Excellent
N/R
Fair
Fair
Poor
Fair
Fair
Fair
Fair
Fair
Dichloroethenes
4
Vinyl Chloride
Tetrachloroethanes
Trichloroethanes
5
6
N/R
Good
Good
Poor
Good
Fair
Fair
Poor
Good
Dichloroethanes7
N/R
Good
Good
Fair
Good
Fair
Fair
Poor
Good
Chloroethane
N/R
Good
Good
Fair
Good
Fair
Fair
Poor
Good
Carbon tetrachloride
N/R
Excellent
Good
Poor
Excellent
N/R
N/R
N/R
Excellent
Chloroform
N/R
Good
Good
Poor
Good
N/R
N/R
N/R
Good
Dichloromethane
N/R
Good
Fair
Poor
Fair
N/R
N/R
N/R
Fair
Methylene Chloride
N/R
Good
Fair
Poor
Good
Poor
Poor
Poor
Good
Pentachlorophenol (PCP)
Good
Good
Good
Good
Good
Fair
Fair
Fair
Good
Chloro- & Dichlorophenols
Good
Good
Good
Good
Excellent
Good
Good
Good
Excellent
Chlorobenzene
Poor
Fair
Fair
Fair
Excellent
Good
Good
Good
Excellent
Di and trichlorobenzenes
Poor
Fair
Fair
Fair
Excellent
Good
Good
Good
Excellent
.
Chlorinated aromatic contaminants
Explosives, energetics and breakdown products
RDX and HMX
Good
Good
Good
Good
Good
Good
Good
Good
Good
TNT and DNT
Poor
Poor
Poor
Poor
Good
Poor
Poor
Poor
Good
Di and Trinitrobenzenes
Fair
Fair
Fair
Fair
Fair
Fair
Fair
Fair
Good
Mono and dinitrophenols
Good
Good
Good
Good
Good
Good
Good
Good
Good
The Reducers
•
Sodium Bisulphite/Thiosulphate
3NaHSO3 + 2H2CrO4 + 3H2SO4 → Cr2(SO4)3 + 5H2O + 3NaHSO4
Zero Valent Iron (ZVI) ABC+ carbon substrate and ZVI
•
.
Fe0 → Fe2+ + 2eRCl + 2e- + H+ → RH + ClFe0 + RCl + H+ → Fe2+ + RH + Cl-
Anodic Reaction (1)
Cathodic Reaction (2)
Net Reaction (3)
2Fe0 + O2 + 2H2O → 2Fe2+ + 4OH-
Water corrosion (4)
CoCs and Reducers
•
Zero Valent Iron (ZVI) ABC+
Tetrachloroethene (PCE)
Trichloroethene (TCE)
cis 1,2-Dichloroethene (cDCE)
trans 1,2-Dichloroethene (tDCE)
1,1-Dichloroethene (11DCE)
Vinyl Chloride (VC)
Hexachloroethane (HCA)
1,1,2,2-Tetrachloroethane (1122TeCA)
1,1,1,2-Tetrachloroethane (1112TeCA)
1,1,1-Trichloroethane (111TCA)
1,1,2-Trichloroethane (112TCA)
1,1-Dichloroethane (11DCA)
Carbon Tetrachloride (CT)
Trichloromethane (TCM)
Tribromomethane (TBM)
1,2-Dibromoethane (12EDB)
Trichlorotrifluoroethane (Freon 113)
Trichlorofluoromethane (Freon 11)
1,2,3-Trichloropropane (123TCP)
1,2-Dichloropropane (12DCP)
Lindane
Hexachlorobutadiene (HCBD)
N-nitrosodimethylamine (NDMA)
CoCs and Reducers
•
Sodium Bisulphite
Hexavalent Chromium
•
Zero Valent Magnesium (Palladium?)
DDT
DDD
DDE
PCBs
Competing Reactions
Oxidant i.e. MnO4-
Satisfy
Natural Oxidant
Inorganic Demand, t½ = seconds.
Organic Demand, t½ = 10 – 20 min.
Target Compound Mineralization
2.4 lb KMnO4 / lb TCE, t½ = 18 min.
Soil Matrix
Demand (NOD – SOD)
x CO2 + x MnO2 + x Cl- + H+
1.3 lb KMnO4 / lb PCE, t½ = 260 min.
Not significant for permanganate
Oxidant Decomposition
4MnO4- + 4OH-
4MnO4-2 + 2H2O + O2
t½ = 10’s of years
Evaluation Process
What Needs to be Considered
Geology
Geochemical Concerns
• Sands
• Silts
• Clays
• Glacial Till
• Fractured Bedrock
• Target Contaminants
• Natural Oxidant Demand
• Contaminant Phase
• pH
• Alkalinity
• Heavy Metals
Oxidant Selection
Delivery Mechanisms
• Sodium Permanganate
• Potassium Permanganate
• Hydrogen Peroxide
• Ozone
• Sodium Persulfate
• Fenton’s Reagent
• High or Low Pressure Injection
• Hydraulic Fracturing
• Pneumatic Fracturing
• Recirculation Systems
• Reactive Barriers
Design pathway
Evaluation Process
How Much Do I Need To Inject?
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SOD and Calculations for ISCO
SOD and Calculations for ISCO
• CS = Contaminant Concentration in soil (mg/kg)
• CGW = Contaminant Concentration in groundwater (ug/l)
• CNPL = Contaminant Concentration in NAPL phase (mg/l)
• PEb= Effective Porosity
• G = Gallons Water To Be Treated (X*Y*Z*PE)
• YS = Yards of Soil To Be Treated (X*Y*Z)
• S = Stoichiometric requirements per pound of contaminant
• SOD = Soil Oxidant Demand (g/kg)
• SODE = Effective Soil Oxidant Demand %
• SR = Other Scavenging Reactions (g/kg)
• CF = Confidence Factor (contaminants, lithology, hydrogeology,
distribution, contact delivery)
TR = Total Pounds of Oxidant required
TR = { (CS+CGW+CNPL)*G*S + (SOD*SODE+SR)*Ys}*
CF
PCE and TCE + Fenton
Benzene + Fenton
Cloroethenes and RemOx
RemOx Permanganate Oxidation of
Chlorinated Ethenes
+
ClPermanganate
Ion
Complete
Mineralization
PCE + RemOx
4 KMnO4 + 3 C2Cl4 + 4 H2O
6 CO2 + 4 MnO2 + 4 K+ + 12 Cl- + 8 H+
Stoichiometric Mass Requirements:
1.3 g KMnO4 / g PCE
1.1 g NaMnO4 / g PCE
Cl
0
Cl
CAS Rn = [127-18-4]
Molecular Weight : 165.8
Cl
Cl
Melting point: -22.7 oC
Boiling Point @ 101.325kPa: 121.2 oC
Density @ 20oC : 1.623 g/cm3
Solubility in water @ 20 oC : 150 mg / kg
Solubility of water in PCE @ 20 oC : 80 mg. /kg
Ln(PCEt /PCEt=0)
PCE
Reaction Time, minutes
-0.5
-1
-1.5
-2
200
400
600
10
1
12
2
800
TCE + RemOx
2 MnO4- + C2HCl3
2 CO2 + 2 MnO2 + 3 Cl- + H+
Stoichiometric Mass Requirements:
2.4 g KMnO4 / g TCE
2.2 g NaMnO4 / g TCE
Cl
50 100 150 200 250 300
Cl
CAS Rn = [79-01-6]
Molecular Weight : 131.4
Melting point: -87.1 oC
Cl
o
Boiling Point @ 101.325kPa: 86.7 C
Density @ 20oC : 1.465 g/cm3
Solubility in water @ 20 oC : 0.107 %(w/w)
Solubility of water in TCE @ 20 oC : 0.025 %(w/w)
Ln(TCEt/TCE0)
TCE
Reaction Time, minutes
-2
-4
-6
-8
DCE and VC + RemOx
DCE
8KMnO4 + 3C2H2Cl2
6CO2 + 8MnO2 + 8K+ + 6Cl- + 8OH+ + 2H2O
Weight Ratio: KMnO4 4.4 : 1
NaMnO4 3.9 : 1
VC
10KMnO4 + 3C2H3Cl
6CO2 + 10MnO2 + 10K+ + 3Cl- + 7OH+ + H2O
Weight Ratio: KMnO4 8.5 : 1
NaMnO4 7.6 : 1
Energetics + Permanganate
RDX
RDX, an initialism for Research Department Explosive, is an explosive
nitroamine widely used in military and industrial applications. It is also
known less commonly as cyclonite, hexogen and T4. Its chemical
name is cyclotrimethylenetrinitramine; variants include cyclotrimethylenetrinitramine and cyclotrimethylene trinitramine
+ KMnO4
Methylenedinitramine
Hydroxymethylnitramine
Formaldehyde
Formic Acid
Carbon Dioxide
RemOx Oxidation Rates
k (M-1s-1)*
t½(min)**
Trichloroethylene
0.65 ± 0.01
17.8
Perchloroethylene
0.045 ± 0.003
256.7
Cis-dichloroethylene
0.920 ± 0.05
12.6
Trans-dichloroethylene
30.0 ± 2.0
0.4
1,1-dichloroethylene
2.38 ± 0.13
4.9
* Yan & Schwartz. 1999. Journal of Contaminant Hydrology. 37. 343-365.
** 158 mg KMnO4/L, KMnO4 in excess
RemOx in summary
Permanganate Points
•The utilization of permanganates for ISCO of chlorinated
“ethenes” is a proven and maturing market
• Single component oxidant not requiring activation
•Very stable oxidant
•Persistence allow diffusion into tighter matrixes
•Reaction is not pH sensitive
•Lowest carbon footprint for permanganate production in
the world
OBC™ activated persulfate
• OBC™ Oxygen BioChem is a patented
combination of sodium persulfate and food grade
calcium peroxide in one product
• A slow-release oxygen generating formula
designed to provide short-term chemical oxidation
(1-2 months) and long term anaerobic oxidation via
sulfate reduction (1-2 years)
• Fast oxidation via persulfate radicals
• Injected, blended or added prior to backfill
OBC action scheme
Chemical action
1-2 months
SO4•- + e- à SO4-2
E0 = ~ 2.6 v
CaO2 + H20 à Ca(OH) 2 + H2O2
Biological action
up to 2 years
SO42- à 2O2 + S2S2- + Me2+ à SMe↓
29
OBC™ in summary
OBC™ Activated Persulfate Points
•The utilization of OBC for ISCO is a proven and maturing
market for the following contaminats: TPHs (GRO, DRO),
MTBE, hydraulic oils, chlorinated solvents
• pre mixed two components reagent
•Allows for consequent bioremediation (SRBs)
•No need for pH control
•Ideal for mixed contamination
MONITORING
• Contaminants of Concern (CoCs)
• Metals if required
• Oxidant
• pH, RedOx, activators, sulphates (for persulfate)
• colour (permanganate)
On monthly basis for 3 months
or on the basis of site specific conditions
In Summary
Applicability
• Permeable soils (Contact !!)
• Vadose (RemOx, OBC, Ozone)
• Less permeable soils (silt, clay) with fracturing and
persistent oxidants (i.e. Permanganate no Fenton)
• Reactivity with the oxidants/reductants
• Reasonable NOD-SOD
• Source areas
In Summary
Limits
• Impermeable soils
• Activation, pH control (not for permanganate, ZVI, bisulphite)
• Free phase (can be treated by some Fenton, ABC+)
• Exothermic reactions, gas production, explosions
for Fenton
Delivery Technologies
Simplified Injection
Simplified Direct Push Injection
Permanganate Injection Equipment
Permanganate Injection Equipment
Permanganate Injection Equipment
Permanganate Injection Equipment
Permanganate Injection Equipment
Delivery Techniques In Situ Mixing
Delivery Techniques In Situ Mixing
How To Ensure a Successful ISCO Project
• Be confident in your site data
– MIPS or more sampling
• Inject enough oxidant
– Know your PNOD
• Know your goals
• Establish a sampling plan
– Make sure there are enough sample
locations to prove goals
• Design for at least two injections
• Be flexible in the field
EUROPE
Lorenzo Sacchetti
[email protected]
+39 345 40 19 965
CARUS EUROPE
Parque Empresarial de ASIPO - C/ Secundino Roces 3 - Oficina 13-14
33428 Cayes ( Llanera )
Spain
+34 985.785.513 Fax +34 985.785.510
[email protected]
USA
Kelly Frasco
Liz Mueller
Laboratories (USA)
Pamela Dugan
[email protected]
[email protected]
[email protected]