MTBE treatment.pdf
Transcript of MTBE treatment.pdf
Aggregate WaterTreatment Costs due to
MTBE ContaminationArturo A. Keller1
Orville C. Sandall2Robert G. Rinker2Linda Fernandez1Marie M. Mitani1
Britta Bierwagen1Michael J. Snodgrass2
1Bren School of EnvironmentalScience and Management
2Dept. of Chemical Engineering
University of California, Santa Barbara
Cost Elements
z Unit water treatment costyReview of applicable technologies
z Extent of current contaminationyLeaking USTs (LUFTs)yContaminated drinking water wellsyPipeline failuresySurface water reservoirs
z Contribution of MTBE to remediation cost
Unit Water Treatment Costz Applicable TechnologiesyAir StrippingyGranular Activated CarbonyBiofiltrationyAdvanced Oxidation ProcessesyHollow Fiber Membranes
z Scenarios:yHigh concentration/low flowrateyLow concentration/high flowrateyTreat to 5 ug/L
Physicochemical DataProperties at 25oC MTBE ETBE TAME TBA Ethanol
Vapor Pressure (atm) 0.330 0.200 0.090 0.054 0.069Aqueous solubility(mg/L)
43,000 to54,300
26,000 20,000 ¥ ¥
Henry’s Law Constant(Mol L Mol-1 L-1)
0.024 to0.123
0.109 0.052 4.3x10-4
to5.9x10-4
2.1x10-4 to2.6x10-4
Octanol-WaterPartitioning Coefficient,Kow (-)
101.2 101.74 No data 100.35 10-0.16 to10-0.31
Boiling Point (oC) 55.2 67 86.3 82.9 78.5Density (g/mL) 0.74 0.73 0.77 0.79 0.79Molecular Weight(g/mole)
88.15 102.18 102.18 74.12 46.07
CAS Number 1634-04-4 637-92-3 994-05-8 75-65-0 64-17-5
Cases Used in Study
Case 1 2 3 4 5 6 7 8 9 10
Concentration (ug/L) 100 100 100 500 1000 5000 100 500 1000 5000Flow rate (gpm) 1000 500 100 100 100 100 10 10 10 10
z Scenarios:yLUFT: High concentration/low flowrateyDrinking water well or surface water
reservoir: Low concentration/high flowrateyTreat to 5 ug/L
Air StrippingLow Flow
rateMediumFlow rate
High Flowrate
Very HighFlow rate
Water Flow rate(m3/s)
6.3x10-4
(10 gpm)0.0063
(100 gpm)0.031
(500 gpm)0.063
(1000 gpm)
Tower Diameter 0.36 m(1.2 ft)
1.13 m(3.7 ft)
2.54 m(8.3 ft)
3.6 m(11.8 ft)
Tower Height Packing height + 3 mPacking Material 1" Intalox SaddlesVolumetric Air-Water Ratio
150:1
PlannedOperatingSchedule
24 hours/day, 7 days/week, 52 weeks/yr
Air Stripping
1
10
100
1000
10 4
10 100 1000 10 4
MTBE Only
MTBE with Other VOCs
Flow
rate
(gal
/min
)
MTBE Concentration (ppb)
No off-gas treatment needed
MTBE Concentration (ug/L)
Flow
rate
(gal
/min
)
Air Stripping
-5
-4
-3
-2
-1
3.0E-03 3.1E-03 3.2E-03 3.3E-03 3.4E-03 3.5E-03
1/T (K)
ln(H
) (d
imen
sion
less
)
Robbins et al., 1993
VP-Solubility Method
Method of Rinker & SandallSPME/GC/MS Method
Air Stripping
0
20
40
60
80
100
120
140
5 10 15 20 25 30 35 40 45
Temperature (oC)
Pac
ked
heig
ht (m
)
Cases 1,2,3,7
Cases 4,8
Cases 5,9
Cases 6,10
Effluent Concentration = 5 ppb
Air Stripping
Case 1 2* 3* 4* 5 6 7* 8* 9* 10*Concentration (ug/L ) 100 100 100 500 1000 5000 100 500 1000 5000
Flow rate (gpm) 1000 500 100 100 100 100 10 10 10 10MTBE Effluent at 5 ug/L
No air treatment 0.23 0.25 0.40 0.59 0.68 0.88 1.54 2.30 2.65 3.55Thermal Oxidation w/o heat
recovery0.56 0.62 0.93 1.17 1.28 1.54 3.07 3.56 3.96 5.92
Thermal Oxidation with heatrecovery
0.50 0.53 0.76 0.84 0.88 0.97 2.35 2.68 2.84 3.22
GAC for air treatment 0.66 0.70 1.08 1.58 1.86 2.81 2.90 4.37 5.14 7.45Gas Phase Biofilter for air
treatment0.33 0.41 0.73 0.97 1.07 1.33 3.51 4.60 5.11 6.42
Benzene Effluent at 1 ug/LBenzene (no air treatment) 0.16 0.17 0.29 0.38 0.42 N.A. 1.08 1.36 1.47 N.A.
Air Stripping Treatment Costs ($/1000 gal)
Granular Activated CarbonFlow Diagram for GAC with Steam Regeneration
GACTank
GACTank
GACTank
Condenser Decanter
1
4
5
2
3
6
7
8
1. Influent water + MTBE2. Treated water3. Saturated steam4. MTBE + water vapors5. Condensed MTBE + water6. MTBE (liquid)7. Water with dissolved MTBE8. Treated water
Normal Operation Regeneration 1st Tank
Legend1
MTBE Storage
GAC
Cs = 11.699 Cw0.7101
r2 = 0.9987
0.01
0.10
1.00
10.00
0.0001 0.0010 0.0100 0.1000 1.0000
MTBE Concentration, Cw (mg/L)
Equ
ilibr
ium
GA
C C
once
ntra
tion,
Cs
(mg/
g)Equilibrium Adsorption Isotherm for MTBE on GRC-22
data from Calgon Carbon Corporation, 1998
GAC
Case 1 2 3 4 5 6 7 8 9 10Concentration (ug/L ) 100 100 100 500 1000 5000 100 500 1000 5000
Flow rate (gpm) 1000 500 100 100 100 100 10 10 10 10Low organics, replace GAC 0.65 0.66 0.93 1.43 1.77 3.07 1.20 1.81 2.24 3.85High organics, replace GAC 0.74 0.76 1.03 1.65 2.08 3.77 1.32 2.09 2.62 4.71Low organics, regenerateGAC
0.34 0.38 0.55 0.81 0.98 1.67 1.98 2.25 2.50 3.29
High organics, regenerateGAC
0.39 0.44 0.61 0.93 1.15 2.05 2.18 2.60 2.92 4.02
Benzene, low organics,replace GAC
0.17 0.18 0.42 0.43 0.43 N.A. 0.57 0.58 0.59 N.A.
GAC Treatment Costs ($/1000 gal)
Advanced Oxidation
ln k = -5253.5/T + 23.952r2 = 0.9483
5.5
6
6.5
7
7.5
0.0031 0.0032 0.0033 0.00341/T (K-1)
ln k
(M-1
s-1
)Temperature Dependence of MTBE Oxidation with Ozone
Advanced Oxidation
Case 1 2 3 4 5 6 7 8 9 10Concentration (ug/L ) 100 100 100 500 1000 5000 100 500 1000 5000
Flow rate (gpm) 1000 500 100 100 100 100 10 10 10 10Reactor Volume (gal) 1000 500 200 500 500 1000 100 100 100 200Number of Reactors 3 3 2 2 2 3 1 2 2 2
Ozone Production (kg/hr) 0.25 0.12 0.025 0.12 0.25 1.24 0.003 0.012 0.025 0.12
AOP Operating Conditions
Advanced Oxidation
Case 1 2 3 4 5 6 7 8 9 10Concentration (ug/L ) 100 100 100 500 1000 5000 100 500 1000 5000
Flow rate (gpm) 1000 500 100 100 100 100 10 10 10 10Only Ozone 0.29 0.41 1.17 1.52 1.68 3.48 3.55 4.19 4.19 5.78
Ozone + GAC 0.67 0.75 1.44 1.95 2.14 3.45 5.99 6.02 6.05 7.25UV/Hydrogen Peroxide 0.62 0.65 1.30 1.35 1.40 1.83 3.15 3.20 4.01 4.06
Ozone/H2O2 studies under way
AOP Treatment Costs ($/1000 gal)
Hollow Fiber Membranes
Water Inlet Port Water Outlet PortHollow Fiber
(Bundle may have 100 to 10,000 fibers)
Shell End-Plate
Potting Material(typically Epoxy)
Module ShellVapors/Gases Outlet Port
Controlled Air Inlet Port
Typical Hollow Fiber Membrane Model Construction
Hollow Fiber Membranes
Lumen
Typical wall thickness:10-50 mm
Inside diameter: 90-450 mm
Outside diameter: 100-500 mm
Typical porosity: 10-80%Pore size: 0.01 to 0.1 mm
Hollow Fiber cross-sectional view
Hollow Fiber MembranesHollow Fiber Membrane Process Diagram
Water Pump
Hollow FiberMembrane Module
VacuumPump
Air/Gas inlet
Regulating Valve
TreatedWater Effluent
InfluentWater with
Organics
Vacuum Gauge
Adsorption,Catalytic or
Thermal Oxidation
Hollow Fiber MembranesComparison between theoretical and experimental
removal efficiency for Hollow Fiber Membrane
y = 1.006x - 0.0045r2 = 0.9464
0%
20%
40%
60%
80%
100%
0% 20% 40% 60% 80% 100%
Experimental Removal Efficiency
Theo
retic
al R
emov
al E
ffici
ency
Hollow Fiber MembranesPredicted performance for commercial membrane
50%
60%
70%
80%
90%
100%
10 15 20 25 30 35 40
Temperature (oC)
Theo
retic
al R
emov
al
10 gpm
15 gpm
20 gpm
Hollow Fiber Membranes
Case 1 2 3 4 5 6 7 8 9 10Concentration (ug/L ) 100 100 100 500 1000 5000 100 500 1000 5000
Flow rate (gpm) 1000 500 100 100 100 100 10 10 10 10MTBE (no air treatment) 0.69 0.72 0.78 0.78 1.16 1.16 1.05 1.05 1.46 1.46MTBE (with air treatment) 1.05 1.12 1.35 1.66 2.25 3.05 1.91 2.29 2.96 3.96Benzene (no air treatment) 0.69 0.72 0.78 0.78 1.16 N.A. 1.05 1.05 1.46 N.A.
HFM Treatment Costs ($/1000 gal)
Comparative Cost Study
1 2* 3* 4* 5 6 7* 8* 9* 10*Concentration (ug/L ) 100 100 100 500 1000 5000 100 500 1000 5000
Flow rate (gpm) 1000 500 100 100 100 100 10 10 10 10Air Stripping
MTBE (no air treatment) 0.23 0.25 0.40 0.59 0.68 0.88 1.54 2.30 2.65 3.55MTBE (with air treatment) 0.33 0.41 0.76 0.84 0.88 0.97 2.35 2.68 2.84 3.22
GACMTBE w/low organics 0.34 0.38 0.55 0.81 0.98 1.67 1.20 1.81 2.24 3.85MTBE w/high organics 0.39 0.44 0.61 0.93 1.15 2.05 1.32 2.09 2.62 4.71
AOPOzone only 0.29 0.41 1.17 1.52 1.68 3.48 3.55 4.19 4.19 5.78
Ozone + GAC 0.67 0.75 1.44 1.95 2.14 3.45 5.99 6.02 6.05 7.25UV/Hydrogen Peroxide 0.62 0.65 1.30 1.35 1.40 1.83 3.15 3.20 4.01 4.06
Hollow Fiber MembraneMTBE (no air treatment) 0.69 0.72 0.78 0.78 1.16 1.16 1.05 1.05 1.46 1.46MTBE (with air treatment) 1.05 1.12 1.35 1.66 2.25 3.05 1.91 2.29 2.96 3.96*air treatment may not be required for this system.
Treatment Costs ($/1000 gal)
Unit Water Treatment CostTotal Groundwater Site Remediation
Gasoline withMTBE
ConventionalGasoline
Range Typical Range TypicalSite
investigation$30,000 -250,000
$100,000 $20,000-170,000
$77,000
SoilRemediation
$22,000 -260,000
$97,000 $22,000-260,000
$97,000
Watertreatment
$140,000-240,000
$190,000 $55,000-180,000
$110,000
Total $190,000-750,000
$390,000 $97,000-610,000
$280,000
AnnualizedCost
$95,000-150,000
$130,000 $50,000-120,000
$93,000
Groundwater ContaminationAggregate Annualized Cost of UST Treatment
Gasoline with MTBE Conventional GasolineNumberof sites
90% fullremediation
10%natural
attenuation
20% fullremediation
80% naturalattenuation
Older activeUSTs
350 $60 to 240million
$2 to 11million
$7 to 44million
$13 to 70million
Older USTsites
2100 $360 to1,420million
$40 to 160million
$42 to 270million
$81 to 420million
Subtotal 2450 $420 to1,660million
$42 to 170million
$49 to 310million
$94 to 490million
Annualupgraded
tank failures30-880
$15 to 590million
$2 to 68million
$2 to 110million
$8 to 180million
Aggregate Annualized Cost ofWater Treatment1
Low Estimate High EstimateOlder UST sites $320 million $1030 millionFuture UST sites $7 million $370 million
Pipelines $5 million $10 millionPublic Wells $2 million $36 millionPrivate Wells $1 million $4 million
Surface Water $4 million $30 millionTotal $340 million $1,480 million
1relative to conventional gasoline
Conclusions
z Unit Water Treatment Costs for MTBE are40 to 100% greater than for commongasoline components (e.g. BTEX)z MTBE will be at much higher
concentrations than other componentsz Site characterization and remediation
costs are higher for MTBE than BTEX,given the greater extent of contamination
Conclusions
z Natural attenuation is less likely to be anoption due to the low biodegradability ofMTBE under natural conditionsz UST failures in past, present and future
place groundwater supplies at risk;immediate remediation is cheaperz Legacy of MTBE is treatment costs of
hundreds of millions of dollars per year untilthe sources are removed
Acknowledgements
z Study funded under SB 521 through UCToxic Substances Research & TeachingProgramz Contributions fromyE. Schroeder et al. (1998): biofiltrationyM. Suffet et al. (1998): activated carbonyS. Hitz, H. Kun, A. Peterson, B. Smith & M.
Yoshioka, graduate students at the BrenSchool