assessment and disposal of arsenic treatment residuals...sbrp/epa workshop feb. 28 - mar. 01, 2005 2...
TRANSCRIPT
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Assessment and Disposal of
Arsenic Treatment Residuals
SBRP/EPA Workshop Feb. 28 - Mar. 01, 2005
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2 Philosophy and Format
Road test research Proactive environmental engineering Condense normal timeline Cut across conventional delineations Limited size
facilitate open discussion narrow focus/broad expertise solutions/directions beyond the problems
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3 Changes and Impacts
•2001revised arsenic in D.W. standard •10 ppb MCL (from 50 ppb) •Implementation by 2006-2012
•Predicted impacts •4000 new utilities impacted ( >95% small) •8M lb solid residuals annually (30,000 # As /yr) •Present and future Superfund/RCRA sites
•Residuals hazard assessment •Toxicity characteristic leaching procedure (TCLP) •Waste extraction test (WET)
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4 Next Steps for As Residuals
S1. Simulate landfills/repositories to determine appropriate performance bar
S2. Develop tractable protocols based on engineering critical leaching mechanisms to clear bar
S3. Evaluate (technically & economically) treatment options, including stabilization, alternative sorbents, etc.
S4. Develop and evaluate hybrid (conventional & innovative) disposal options
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6 Test/Landfill Characteristics
Test pH ORP (mV)
Alkalinity (mg/L as CaCO3)
TOC (mg/L)
TDS (mg/L)
Ionic Strength
(M)
TCLP 4.95 103.5 766 38.6 1480 0.08 WET 5.05 74 7940 55.8 5160 0.10 SL1 7.03 121.4 1500 1050 5200 0.03 SL2 7.55 -37 12500 1310 8600 0.49 LL1 6.82 36.1 1100 160 3600 0.33 LL2 4.5-9.0 N/R* 300-11500 30-29000 2000-60000 N/R LL3 6.5-8.2 N/R 1250-8050 N/R 1960-16800 N/R LL4 6.2-7.1 N/R N/R 236-3160 N/R N/R
N/R* - Values Not Reported LL1 – Leachate collected from Tangerine Road Landfill, Tucson, AZ. LL2 – Leachate composition reported in Christensen et al, 2001 (21) LL3 – Leachate composition reported in Jang et al, 2003. (22) LL4 – Leachate composition reported in Hooper et al, 1998. (5)
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7 Our Corollary Research
Treatment systems evaluation (IHS funding) Removal technology development (State of AZ/
SBRP) Residuals assessment (SBRP/AZ State funding)
Adequacy of TCLP and WET What is adequate? Alternative test development Other contaminants and scenarios
Residuals stabilization (SBRP/AWWARF/AZ State funding)
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0
0.2
0.4
0.6
0.8
1
1.2
Extra
ctan
t Ars
enic
(m
g/L
as A
s)
AA, 18hr AA, 48hr
GFH, 18hr GFH, 48hr
Initial Loading: AA, 31 ppb; GFH, 22 ppb
TCLP LL WET SL1 SL2
8 Solid Media Leaching
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9 Residuals Assessment Tests
Guiding Premise: test induces leaching as or more aggressively
than conditions of non-hazardous waste disposal
TCLP WET Mature Landfill
pH 4.95 5.05 7-9
Bioactivity abiotic abiotic biotic
Duration 18 hr 48hr weeks /months
Active Reage nt
acetate c itrate Mix of organics & inorganics
Redox Condition
oxidizing neutral reduc ing
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10 Immediate Findings
•TCLP vs. WET Variables (batch test mode) •agitation method (tumbler (T) > shaker (W)) •headspace (N2 (W) > air (T)) •duration (48 hr (W) > 18 hr (T)) •reagent (citrate (W) > acetate (T))
•Landfill vs. Standard Variables (batch test mode) •pH (6.8 (LL) > ~5 (T&W)) •TOC (above 160 ppm (LL) > below 60 ppm (T&W)) •ORP (below 50 mV (LL) > above 50 mV (T&W))
•Study limitations •batch vs. continuous flow •abiotic vs. biotic •excess (non-reactive) vs. limiting (reactive) substrate
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SYRINGE PUMP (FLOW RATE 0.31mL/min)
INFLUENT GAS COLLECTION
MARIOTTE
FLASK
10% NaOH SOLUTION
UNSATURATED ZONE
SATURATED ZONE
GRAVEL
GRAVEL
WATER WITH pH LEVEL INDICATOR
DEAERATED, COLLECTION DEIONIZED FLASK WATER
SAMPLING PORTS • 23% SHREDDED PAPER • 46% YARD WASTE • 31% SOLID RESIDUAL • 4L ANAEROBIC DIGESTOR SLUDGE
EFFLUENT
11 S1. Setting the bar
Landfill Simulation Columns
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As
(ppb
) 2500
3000 3500
4000 As(III)
DMA(V)
As(dissolved)
MMA(V)
As(V)
As(digested)
1000
1500 2000 HCO3
VFA
500
0 0 200 400 600 800
time (days)
12 S1. Setting the bar
GFH Column Leachate
Equilibrium As Concentration : 25.66ppb
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13 S1. Setting the bar
GFH Column Leachate
0.00
100.00
200.00
300.00
400.00
500.00
600.00
0 200 400 600 800
Time (days)
Fe
(in
pp
m)
0
1000
2000
3000
4000
As(
in p
pb
)
Fe (total) As(total)
-
S1. Setting the bar
Sorb-33 Column Leachate 14
0 50
100 150 200 250 300 350 400 450 500 550 600
0 50 100 150 200 250 300
Time (days)
Tot
al F
e (m
g/L
)
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Tot
al A
s (p
pb)
Total Fe Total As
-
0
0.1
0.2
0.3
0.4
0.5
0.6
Frac
tion
As
deso
rbed
AA
GFH
4.59
14.96
12.25
50.84
28.21
152.5
7 8 9pH
15 S2. New Protocol Development
pH Effects
10
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16 S2. New Protocol Development
Anion’s Effects
Anion Landfill Leachate Range (in mg/L) (Bagchi, 1994)
Concentration Used in
Competition Trials
(in mg/L)
Fraction As expected to leach due to
concentration of anion in LL
Fraction of total leaching attributable to each anion in the
SLL-theo
Activated Alumina Phosphate 0.11- 234 20 0.002 0.04
Bicarbonate 34- 15,050 1,200 0.008 0.15 Sulfate 105- 4,900 500 0.002 0.04 Silicate 5.1-51 10 0.001 0.02 NOM 76-40,000 200 0.04 0.75
Granular Ferric Hydroxide Phosphate 0.11- 234 20 0.0007 0.03
Bicarbonate 34- 15,050 1,200 0.012 0.48 Sulfate 105- 4,900 500 0.0008 0.03 Silicate 5.1-51 10 0.0013 0.05 NOM 76-40,000 200 0.01 0.4
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TCLP LL WET SL1 SL2 0
0.2
0.4
0.6
0.8
1
1.2
Extra
ctan
t Ars
enic
(m
g/L
as A
s)
AA, 18hr AA, 48hr
GFH, 18hr GFH, 48hr
Initial Loading: AA, 31 ppb; GFH, 22 ppb
17 S2. New Protocol Development
Reductant + TOC Effect
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18 S3. Treatment & Stabilization Options
AFH Crystallization
D7
0
100
200
300
D14
0
500
1000
D24
0
500
1000
1500
D0
0 100 200 300 400
20 30 40 50 60 70
D42
0 200 400 600 800
1000 1200 1400 1600 1800
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19 S3. Treatment & Stabilization Options
As Release & Crystallization
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0 300 600 900 1200 AGING TIME(Hrs)
As(t)
/As(T
)
pH7
pH8
pH9
pH10
pH11
pH12
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20 Broader Implications
•Arsenic as an elemental contaminant •no destructive technologies •media and speciation transformations only •surrogate for heavy metals, metalloids, radionuclides
•Arsenic as a redox-sensitive, oxyanion •inverse pH behavior to metals •microbially mediated fate and transport •typically most mobile in reduced form •surrogate for V, Mo, Se, S, Cl, N, P
•Arsenic as a ‘natural’ contaminant •primarily non-anthropogenic sources •naturally diffuse but anthropogenically concentrated •surrogate for Rn, U, Se, S, F, Br, V
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21
Batch Adsorption Experiments
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22 AA Adsorption Edge
0
0.2
0.4
0.6
0.8
1
4 6 8 10 12 pH
C/C
o
Co = 0.125mM Co = 0.05mM Co = 0.0125mM Co = 0.005mM Co = 0.00125mM
• Co - Initial arsenic concentration in solution • C - Equilibrium arsenic concentration in solution
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GFH Adsorption Edge
Co = Initial concentration of As in solution (total As in the system) C = Concentration of As in solution at equilibrium Solid Loading = 25g/L
23
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
5 6 7 8 9 10 11
pH
C/C
o
Co= 1.66mM Co= 8.33mM Co= 16.6mM Co= 83.3mM
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24
Comparative Leaching Tests
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25
-
26
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27 Activated Alumina
0 100 200 300 400 500 600 700 800 900
1000
TCLP WET LL SL1 SL2
Leac
hate
As
Conc
. (pp
b as
As) 18hr
48hr
Concentration of As in solution at equilibrium prior to leaching tests = 21.8ppb Sorbed concentration of As = 1.27mgAs/gAA. Test conditions: No N2 headspace, end-over-end tumbler.
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28 Granular Ferric Hydroxide
0
200
400
600
800
1000
1200
TCLP WET LL SL1 SL2
Leac
hate
As
Con
c. (p
pb a
s A
s)
18hr
48hr
Concentration of As in solution at equilibrium prior to
leaching tests = 31ppb Sorbed concentration of As = 7.2mgAs/gGFH. Test conditions: No N2 headspace, end-over-end tumbler.
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29 Ferric Hydroxide Sludge
1
10
100
1000
10000
100000
1000000
10000000
TCLP WET LL
Leac
hate
As
Con
c. (p
pb a
s A
s) 18hr 48hr
Concentration of As in solution at equilibrium prior to
leaching tests = 1040ppb Sorbed concentration of As = 20.3mgAs/gFe. Test conditions: No N2 headspace, end-over-end tumbler.
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30
Competitive Anion Effects
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31 Activated Alumina Anion Effect Anion (Moles As
released/ mole
(Moles As released/
mole
(Moles As released/
mole
Fraction sorbed As expected to leach due to concentration of anion in LL
pH7anion pH9)high pH7anio pH9n)low pH7anion)a pH9verage
Phosphate 279 113 3.05 1.52 9.24 4.69 0.002
Bicarbonate 0.92 0.58 0.014 0.007 0.043 0.025 0.008
Sulfate 0.352 0.143 0.017 0.014 0.045 0.028 0.002
Silicate 12 8.6 0.56 0.68 2.6 2 0.001
NOM 391 336 0.41 0.23 2.35 1.13 0.04
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32 GFH Anion Effect Anion (Moles As
released/ mole
(Moles As released/
mole
(Moles As released/
mole
Fraction sorbed As expected to leach due to concentration of anion in LL
pH7anion pH9)high pH7anio pH9n)low pH7anion)e
pH9averag
Phosphate 357 244 4.02 2.09 10.5 6.07 0.0007
Bicarbonat e
8 4 0.027 0.023 0.24 0.11 0.012
Sulfate 0.698 0.458 0.021 0.005 0.098 0.054 0.0008
Silicate 32 21 2.1 0.62 5.4 3.7 0.0013
NOM 1064 374 0.7 0.19 3.9 0.97 0.01
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33
Column Experiment Methods
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34 Column Packing Composition Specifications Activated
Alumina GFH E-33
Mass of Residual
1017g 527g 509g
Total Amount of As
1.29g 2.86g 2.61g
Initial Sorbed As Conc.
1.27mgAs/gAA 5.42mgAs/gGF H
5.13mgAs/gE33
Initial equilibrium As
conc.
193ppb 25.6ppb 11ppb
Duration of run 302 days 808 days 274 days
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35
Activated Alumina Column
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36 pH
6
6.5
7
7.5
0 50 100 150 200 250 300 350
time (days)
pH
-
37 Alkalinity
0 1000 2000 3000 4000 5000 6000
0 50 100 150 200 250 300 350
time (days)
alk
alin
ity
(m
g/L
)
-
38 ORP
-25
-15
-5
5
15
25
0 50 100 150 200 250 300 350
time (days)
OR
P (
mV
)
-
39 DOC
0
1
2
3
4
5
6
7
0 50 100 150 200 250 300 350
time (days)
DOC
(g/L
)
-
40 Arsenic
0
500
1000
1500
2000
0 40 80 120 160 200 240 280 320
Time(days)
Co
nc
(pp
b)
As(III) As(V)
As(dissolvedl) As (total)
* Small amounts of MMA(V), DMA(V) and MMA(III) were also observed in the effluent.
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41 Fractional Arsenic Leached
0
0.02
0.04
0.06
0.08
0.1
0.12
0 50 100 150 200 250 300 350
Time (days)
Fra
ctio
nal
As
Lea
ched
-
42
GFH Column Results
-
43 pH
6
6.5
7
7.5
8
8.5
9
9.5
10
0 200 400 600 800 1000
days
pH
-
44 Alkalinity
0
500
1000
1500
2000
2500
3000
3500
0 200 400 600 800
days
Alk
alin
ity (m
g/L)
-
45 ORP
-250
-200
-150
-100
-50
0 0 100 200 300 400 500 600 700 800
days
OR
P (
mV
)
-
46 DOC
0
500
1000
1500
2000
2500
3000
0 100 200 300 400 500 600 700
days
DO
C (m
g/L)
-
As
(pp
b)
4000 As(III) 3500 As(V) 3000 As(dissolved) 2500 As(digested) 2000
1500
1000
500
0 0 200 400 600 800
time (days)
47 GFH Column Results
-
Fe (m
g/L)
600
400
500 Fe (dissolved) Fe (digested)
300
200
100
0 0 200 400
time (days)
600 800
48 GFH Column Results
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49 Overall Picture
0.00
100.00
200.00
300.00
400.00
500.00
600.00
0 200 400 600 800 1000
Time (days)
Fe
(in
pp
m)
0
1000
2000
3000
4000
As(
in p
pb
)
Fe (total) As(total)
-
50 Fractional Arsenic Leached
0 0.05 0.1
0.15 0.2
0.25 0.3
0.35 0.4
0.45 0.5
0 200 400 600 800 1000
time (days)
Fra
ctio
nal
As
Lea
ched
-
Fe(
mg
/L)
250
200
150
100
50
0 0 200
>5U 0.8U
-
As
(p
pb
)
2500
2000
1500
1000
500
0
>5U 0.8U
-
53
E-33 Column Results
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54 pH
6
7
8
0 50 100 150 200 250 300
time
pH
-
55 Alkalinity
900
1400
1900
2400
0 50 100 150 200 250 300
time
Alk
alin
ity
(m
g/L
)
-
56 E-33 Column Results
0
20
40
60
80
0 50 100 150 200 250 300
time (days)
Fe
(mg
/L)
Fe(II) Fe(III) Fe(dissolved) Fe(total)
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57 E-33 Column Results
0 1000 2000 3000 4000 5000
0 50 100 150 200 250 300
time (days)
As
(PP
B)
As(III) As(V) As(dissolvedl) As(total)
-
58 Fractional Arsenic Leached
0
0.05
0.1
0.15
0.2
0.25
0.3
0 50 100 150 200 250 300
Time (days)
Fra
ctio
nal
As
Lea
ched
-
59
Iron Sludge Column Results
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60 pH
6
6.5
7
7.5
8
8.5
9
0 20 40 60 80 100 120 140 160
Time (days)
pH
-
61 Alkalinity
3000
4000
5000
6000
7000
8000
0 20 40 60 80 100 120 140 160
Time (days)
Alk
alin
ity
(mg
/L)
-
62 ORP
-400
-300
-200
-100
0
100
200
300
0 20 40 60 80 100 120 1
Time (days)
OR
P (
mV
)
40
-
63 Arsenic
0
50000
100000
150000
200000
250000
0 20 40 60 80 100 120 140
Time (days)
As
(pp
b)
As (total) As (dissolved) As(III) As(V)
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64 Iron
0.00 100.00
200.00 300.00 400.00
500.00 600.00
700.00 800.00
0 20 40 60 80 100 120 140
Time (days)
Fe
(in
mg
/L)
Fe (total) Fe (dissolved) Fe(II) Fe(III)
Assessment and Disposal of Arsenic Treatment ResidualsPhilosophy and FormatChanges and ImpactsTest/Landfill CharacteristicsOur Corollary ResearchSolid Media LeachingResiduals Assessment TestsS1. Setting the barLandfill Simulation ColumnsS1. Setting the barGFH Column LeachateS1. Setting the barSorb-33 Column LeachateS2. New Protocol DevelopmentpH EffectsS2. New Protocol DevelopmentAnion’s EffectsS2. New Protocol DevelopmentReductant + TOC EffectS3. Treatment & Stabilization OptionsAFH CrystallizationS3. Treatment & Stabilization OptionsAs Release & Crystallization