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Technical Advisory Group Meeting “Sustainable Management of Pollutants Underneath Landfills”

“Onsite Treatment of Leachate Using Energized Processes”

“Critical Examination of Leachate Clogging” By D.E. Meeroff (Florida Atlantic University)

Funded by the Hinkley Center for Solid and Hazardous Waste Management (HCSHWM)

DATE: Friday, March 15, 2013

TIME: 1:00 pm

WHERE: Florida Atlantic University Boca Raton Campus

Computer Center Building

CM Building (22), Room 130 (Studio 1)

777 Glades Road, Boca Raton, Florida 33431

Attendance:

Dan Meeroff (FAU), Tim Vinson (Hinkley Center), Cleevens Geurrier (FAU),

Christine Lyons (FAU), Khaled Sobhan (FAU), Ahmed Albasri (FAU), Frank

Youngman (FAU), Kevin Kohn (University of Florida), Art Torvela (FDEP), Amede

Dimonnay (FDEP)

1. Opening address by Dr. Meeroff followed by introduction of the group members

and participants both through GoToMeeting and live (1:03 pm)

2. Introduction to Landfill Technology Research by Dr. Meeroff

Dr. Meeroff presented the agenda of the meeting, the objectives of the research, and

introduced the speakers. Dr. Meeroff showed the TAG members the project website

(http://labees.civil.fau.edu/leachate.html).

3. Pilot Studies of Photocatalytic Oxidation of Leachate by Frank Youngman

Frank began discussing the background of his research. He explained how the

photocatalytic oxidation treatment mechanism works. Then he went over the

methodology of the pilot scale experiments. He reported on the progress of catalyst

optimization, process removal efficiency and kinetics of COD, ammonia, and color,

and he described ongoing catalyst recovery experiments. He presented a

preliminary cost analysis of the process based on his findings to date, and then

provided recommendations for modifying the process to achieve better removal

efficiencies. Tim Vinson asked Frank to compare the UV dose to previous work to

clarify the differences. Tim Vinson also asked if it was possible to shift the amount of

light while keeping a constant level of TiO2 in order to use less catalyst. He also

stated that the reaction kinetics make the photocatalyst act like a reactant not a

catalyst. He asked if the catalyst is available in bigger particle sizes to facilitate the

separation of the catalyst at the end of the run. Tim Vinson also asked about the fate

of the ammonia if the system is not closed. Perhaps the ammonia is boiling off due

to the elevated temperature in the unit. It was suggested to trap the gases and test

for ammonia in the offgas. Frank and Dr. Meeroff responded by explaining the pH

effect for ammonia removal such that loss of gaseous ammonia would not be

favored at these pH values and temperatures, but no direct measurements of

gaseous ammonia in the treatment offgas have been taken. Frank thought that it

would be interesting to see if the dose of catalyst could be lowered to below 2 g/L

while increasing the UV radiation above 0.3 mW/cm2, which is the current upper

limit of the pilot treatment unit. Frank also responded to a question about scale up

issues with regards to determining the catalyst dose and UV operating conditions.

Since the demonstration testing has not reached the sewer disposal target for COD

and ammonia, Frank responded that modifications to the unit must be made with

respect to increasing the UV dose and increasing the time in the reaction zone. Art

Torvela mentioned that landfill leachate treatment processes should be tested

against total recoverable petroleum hydrocarbons (TRPH) and chlorinated solvents.

He mentioned the target limits for TRPH is 90 ppb and for Benzene, Toluene,

Ethylbenzene and Xylenes (BTEX) it is 200 ppb and for benzene it is 1 ppb. He also

mentioned a CS2 treatment process that has been proposed. Dr. Meeroff observed

that as the amount of leachate generated increases the economics for photocatalytic

oxidation become more favorable. At the same time, if the amount of leachate

increases, the costs for sewage disposal and exceedance surcharges go up, which

also favors photocatalytic oxidation. The key will be to reduce the reaction time

required to meet the 800 mg/L COD level because the ammonia will already be gone

in half the time it takes for the COD to be removed.

4. Laboratory Studies of Groundwater Circulation Well Technology by Ahmed

Albasri

Ahmed began by discussing the background on his research. He explained how the

groundwater circulation well treatment process is intended to work. He was asked

by Dr. Sobhan about the iron levels found in elevated monitoring wells. Ahmed

responded that elevated levels were recorded in the 40 – 85 mg/L range compared to

the groundwater cleanup target of 3 mg/L. Then he went over the methodology of

the aquarium experiments. Dr. Sobhan asked about the scale issue using aquarium

tests. Ahmed explained that the purpose of aquarium tests is to determine the

parameters for scale‐up with regard to air flow rates, depth, well spacing, radius of

influence, etc. He reported rapid removal of iron in the early stages of the process,

but iron speciation has still not been measured. Ahmed explained his steady state

aquarium loading experiments and presented his results for two of the experiments

involving Polk County soils. For one of the experiments, the results showed similar

rapid removal of iron within the first hour of treatment. But for the second aquarium,

the results were inconclusive because the initial concentration was so low (about 10

mg/L vs. 65 mg/L for the first experiment). Ahmed explained that he will continue

loading until a higher steady state concentration is reached and then additional

replicates can be tested. Tim Vinson mentioned a UF dissertation that described how

measuring Fe(II) and Fe(III) is possible in a study focused on Escambia County. Tim

also mentioned that he has seen data regarding pump and treat costs for a similar

sized situation that were on the order of $ 1 million per year. Art Torvela told

Ahmed that he has personally seen reports with existing empirical sparging well

design equations and offered to share those with him. He also mentioned that

Ahmed should investigate a former Delray dump with an iron hotspot because he

has data that he is willing to share and that the cost for an impermeable reactive

barrier technology for this case cost on the order of $2 million.

5. Leachate clogging experiments by Christine Lyons

Christine introduced the joint project with the Hinkley Center, UF, and FAU

regarding the examination of leachate clogging issues at the Solid Waste Authority

of Palm Beach County. She presented her water quality data from several sampling

events, showed a brief video of her sodium hydroxide experiments to create

precipitants in the leachate, and previewed the upcoming demonstration site project

to test potential mechanisms. She mentioned the ongoing leachate collection system

rehab projects which involve 4000 psi jetting and showed the results. Jetting with

10,000 psi and also chemical jetting is planned for the future. Other landfills in the

southeast were identified by Art Torvela as Miami and Monarch Hill that possibly

suffer from leachate clogging too. Kevin Kohn talked about potential mechanisms.

He said that leachate is highly saturated with methane and carbon dioxide and

when the carbon dioxide degasses, the pH jumps up and precipitation of calcium

carbonate is favored. So he described his recent experiment where he collected

degassed leachate/condensate from a landfill gas well at the SWA on March 13, 2013.

He monitored the pH in the degassed leachate and after exposure to air, he

continued to monitor the pH and noticed a slight increase. He tried out his

methodology at the New River Landfill closer to home first before trying the

experiment at the SWA. In general, the pH increased from 7.6 to 8.1 after exposure

to air. He also mentioned ideas about the demonstration project at the SWA which

will involve continuous pumping vs. settling or intermittent pumping. It was

mentioned that permitting is now handled at the Tallahassee level instead of the

local level, so it was suggested to contact Richard Tedder or Joe Lurix to determine

who is handling the SWA case.

6. Adjourn (3pm), thank you for participating!

For more information, contact Dr. Daniel E. Meeroff at:

777 Glades Road, Building 36, Room 222, Boca Raton, FL 33431‐0991

Tel.(561) 297‐3099 FAX.(561) 297‐0493 http://labees.civil.fau.edu

3/18/2013

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Presentation to the HCSHWM Technical Advisory GroupBoca Raton, FL, March 15, 2013

Agenda

1. Introductions/Opening Remarks

2. Photocatalytic Oxidation Studies

3. Circulation Well Experiments

4. Leachate Clogging Project

Dr. Meeroff

Frank Youngman

Ahmed Albasri

Christine Lyons

5. User Input/Open Forum Everyone


Introductions


http://labees.civil.fau.edu/leachate


TAG Meeting

“Onsite Treatment of Leachate Using Energized Processes”

Frank Youngman, BS/MS StudentDepartment of Civil, Environmental & Geomatics Engineering

Laboratories for Engineered Environmental Solutions


Problems with Leachate

Turbidity

Elevated TDS, COD,

NH3

High COD/BOD

ratio

pH toxicity

Heavy metalsPb, As, Cd, Hg

Quantity and quality highly

variable

OdorPathogens

5 Presentation to the HCSHWM Technical Advisory GroupBoca Raton, FL, March 15, 2013

What will we do with leachate in the future?

Hauling

POTWs Deep Injection Wells

Pretreatment

3/18/2013

2


One Solution

• Pre-treatment on-site

• Advanced oxidation using ultraviolet light activation (Energized processes)

• FAU has investigated photochemical iron mediated aeration (PIMA) and TiO2 photocatalysis

• And TiO2 photocatalysis seems to be promising



Titanium dioxide


Hydrogen

Peroxide

Photon (UV)Hydroxyl Radical

Contaminant

Copyright © Trojan Technologies Inc. All Rights Reserved

Water

How Do Energized Processes Work?


h+

e‐Mn+

(aq)

M0(s)

[ Photoreduction ]

+

hν[ Photooxidation ]

Oxygen

Water

TitaniumDioxide


Titanium Dioxide MechanismTiO2TiO2

O2 UV O•

2

H+

O•

2 HO•

2

H2O•OHO

•2 HO

• 2 O2 H2O2

HO•

2 H2O2TiO2 H+

TiO2

H2O2TiO2 TiO2

•OHOH

12

3/18/2013

3


13

Procedures


Wiles Rd

Pow

erline R

oad

Leachate Sample

•Location

•Monarch Hill, formerly known as CDSL

•Pompano Beach, FL

•Sample Point

•Waste Management•South East Step-Up Station



Leachate/ TiO2

CE 584 Falling Film Reactor

• Reservoir (10L)

• Temperature Sensor

• Pump (360 L/h)

• Flow Regulator

• Sampling Port

• 3 Way Valve

• Weir Compartment

• UV Power Source (120W)


Mechanical Improvements• Catalyst

build-up in pump

• Installed a 3-way valve to allow flushing of the pump


Temperature Control• VWR Recirculating Cooler

1150S

• 13 L Capacity

• Temp: -30°C to 150°C

• Filled with Dynalene HC-50 (hydrocoolant)

3/18/2013

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Temperature Curves

0

5

10

15

20

25

30

35

40

45

50

0 50 100 150 200 250 300

Temperature (C)

Time (minutes)

Temp. without Cooling (Richard)

0

5

10

15

20

25

30

35

40

45

50

0 50 100 150 200 250 300

Temperature (C)

Time (minutes)

Temp. with Recirculating Cooler


Parameters• COD/ Alkalinity Testing

• Leachate Sample Volume (8L)

• Degussa P25 TiO2 Catalyst• 4 g/L

• 16 g/L

• 25 g/L

• Constant Aeration

• Recirculating Cooler

• 4 - Hour Test Segments

• Flow Rate: 300 L/hr

• UV dose 0.365mW/cm2


Sample Testing


Experimental Protocol

22


23


Experiment #1

• Leachate collected 9/23/2011

• 4 grams TiO2 per liter leachate

• CODo = 6250mg/L

• Ammoniao = 1710 mg/L as NH3-N

• Alkalinityo = 4630 mg/L as CaCO3

• Coloro = 1125 Platinum Cobalt Units (PCU)

• pH = 8.35

• 44 hour total run

3/18/2013

5


What is the limiting parameter?• Clearly COD

is the limiting parameter

• COD is primary concern for determining reaction kinetics

y = ‐0.009x + 1.0024

y = e‐0.064x

y = e‐0.061x

0

0.2

0.4

0.6

0.8

1

1.2

0 5 10 15 20 25 30 35 40 45 50

C/Co

Time (hours)

C/Co comparing degradation of COD, Ammonia and Alkalinity

COD Ammonia Alkalinity Linear (COD) Expon. (Ammonia) Expon. (Alkalinity)


Reaction Kinetics – Zero Order• Initial Values

• 4.0 g/L TiO2

• CODo = 6250 mg/L

• Zero order kinetics

k = - 56 mg/L-hour

• Estimated time for 100% COD removal would be 112 hoursand 97 hours to get to 800mg/L

y = ‐56.005x + 6261.3R² = 0.9825

0

1000

2000

3000

4000

5000

6000

7000

0 5 10 15 20 25 30 35 40 45 50

COD (mg/L)

Time (hours)

Experiment #1 (4g/L) COD Concentration


Reaction Kinetics – First Order• Initial Values

• 4.0 g/L TiO2

• CODo = 6250 mg/L

• First order kinetics

k = - 0.0112 hour-1

• Displays a higher correlation coefficient than zero order

y = ‐0.0112x + 8.7589R² = 0.9832

8.2

8.3

8.4

8.5

8.6

8.7

8.8

0 5 10 15 20 25 30 35 40 45 50

lnCOD

Time (hours)

Experiment #1 (4g/L) ln(COD Concentration)


Reaction Kinetics – Second Order• Initial Values

• 4.0 g/L TiO2

• CODo = 6250 mg/L

• Second order kinetics

k = 0.000002 L/mg-hour

• Displays a lower correlation coefficient than first and zero order

y = 2E‐06x + 0.0002R² = 0.9779

0

0.00005

0.0001

0.00015

0.0002

0.00025

0.0003

0 5 10 15 20 25 30 35 40 45 50

1/COD

Time (hours)

Experiment #1 (4g/L) 1/(COD Concentration)


Experiment #2



• CODo = 5270mg/L




• pH = 7.52



Reaction Kinetics – Zero Order• Initial Values

• 16 g/L TiO2

• CODo = 5270 mg/L

• Zero order kinetics

k = - 52 mg/L-hour

• Estimated time for 100% COD removal would be 98 hours and 83 hours to get to 800 mg/L

y = ‐52.229x + 5140R² = 0.9776

0

1000

2000

3000

4000

5000

6000

0 5 10 15 20 25 30 35 40 45

COD (mg/L)

Time (hours)

Experiment #2 (16g/L) COD Concentration

3/18/2013

6



• 16 g/L TiO2

• CODo = 5270 mg/L


k = - 0.0129 hour-1

• Displays a higher correlation coefficient than zero order

y = ‐0.0129x + 8.5635R² = 0.9839

8

8.1

8.2

8.3

8.4

8.5

8.6

0 5 10 15 20 25 30 35 40 45

lnCOD

Time (hours)



Reaction Kinetics – Second Order• Initial Values

• 16 g/L TiO2

• CODo = 5270 mg/L

• Second order kinetics

k = 0.000003 L/mg-hour

• Displays a lower correlation coefficient than first order, but higher than zero order

• First order takes precedence

y = 3E‐06x + 0.0002R² = 0.9809

0.00000

0.00005

0.00010

0.00015

0.00020

0.00025

0.00030

0.00035

0 5 10 15 20 25 30 35 40 45

COD (mg/L)

Time (hours)

Experiment #2 (16g/L) 1/(COD Concentration)


Experiment #3



• CODo = 5360mg/L




• pH = 7.54




• 25 g/L TiO2

• CODo = 5360 mg/L


k = - 0.0158 hour-1

y = ‐0.0158x + 8.5351R² = 0.9749

7.8

7.9

8

8.1

8.2

8.3

8.4

8.5

8.6

8.7

0 5 10 15 20 25 30 35 40 45

ln(COD)

Time (hours)



Experiments #4, 5 and 6Parameter Exp. 4 Exp. 5 Exp. 6

Date leachate collected 7/18/2012 7/18/2012 11/2/2012

Catalyst dosage (g/L) 40 25 10

CODo (mg/L as O2) 6,560 6,560 6,064

Ammoniao (mg/L as NH3-N) 1,635 1,635 1,700

Alkalinityo (mg/L as CaCO3) 4,125 4,125 4,375

Coloro (PCU) 756 756 813

pHo 7.66 7.66 7.71

Total treatment time (hours) 24 24 24


y = ‐0.0011x + 1R² = 0.9411

y = ‐0.0015x + 1R² = 0.963

y = ‐0.0022x + 1R² = 0.9235

y = ‐0.0021x + 1R² = 0.9193

y = ‐0.0018x + 1R² = 0.9509

y = ‐0.0018x + 1R² = 0.7468

0.94

0.95

0.96

0.97

0.98

0.99

1

1.01

0 5 10 15 20 25 30

COD lnC/lnCo

Time (hours)

COD Comparison Plot

4 g/L 16 g/L 25 g/L 40 g/L 30 g/L 10 g/L

Linear (4 g/L) Linear (16 g/L) Linear (25 g/L) Linear (40 g/L) Linear (30 g/L) Linear (10 g/L)

3/18/2013

7


k- constant comparisonTiO2 Dosage k‐value

4 g/L ‐0.0102

16 g/L ‐0.0127

25 g/L ‐0.0167

40 g/L ‐0.0160

30 g/L ‐0.0146

10 g/L ‐0.0125

• 25 g/L exhibits the largest k-value


Catalyst Optimization Curve• Previous

curve, which determined the 10 g/L trial

• 10 g/L supported logarithmic curve

y = 2.9746ln(x) + 19.995R² = 0.9697

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 5 10 15 20 25 30 35 40 45 50

% COD Removal at 24 hours

TiO2 dosage (g/L)

Catalyst Optimization Curve

y = 3.0ln(x) + 20R² = 0.97

y = 2.9746ln(x) + 19.995R² = 0.9697

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 5 10 15 20 25 30 35 40 45 50


TiO2 dosage (g/L)


y = 3.0ln(x) + 20R² = 0.97

y = 2.96ln(x) + 19.88R² = 0.97

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

0 5 10 15 20 25 30 35 40 45 50


TiO2 dosage (g/L)


y = 3.0ln(x) + 20R² = 0.97


Ammonia• 4 g/L shows

highest degradation

• k-constant for 4 g/L = -0.0726/hr

y = ‐0.0103x + 1R² = 0.9838

y = ‐0.0039x + 1R² = 0.9585

y = ‐0.004x + 1R² = 0.8967

y = ‐0.0035x + 1R² = 0.943

y = ‐0.0037x + 1R² = 0.9803

y = ‐0.0082x + 1R² = 0.9444

0.75

0.8

0.85

0.9

0.95

1

1.05

0 5 10 15 20 25 30

lnC/lnC0

Time (hours)

Ammonia Comparison Plot

4 g/L 16 g/L 25 g/L 40 g/L 30 g/L 10 g/L



Alkalinity• 10 g/L shows

highest degradation

• k-constant for 10 g/L = -0.0794/hr

y = ‐0.0087x + 1R² = 0.9713

y = ‐0.0041x + 1R² = 0.844

y = ‐0.0028x + 1R² = 0.8301

y = ‐0.007x + 1R² = 0.9113

y = ‐0.0074x + 1R² = 0.9416

y = ‐0.009x + 1R² = 0.9667

0.75

0.8

0.85

0.9

0.95

1

1.05

0 5 10 15 20 25 30

lnC/lnC0

Time (hours)

Alkalinity Comparison Plot

4 g/L 16 g/L 25 g/L 40 g/L 30 g/L 10 g/L



Conclusions

• Based on COD, Ammonia and Alkalinity removal comparison, the optimum range of TiO2 catalyst dose is 4 – 10 g/L.

• At optimal TiO2 range, it would take approximately 160 - 200 hours to achieve 800 mg/L COD target for sewer disposal• Ammonia: 55 - 75 hours to achieve 25 mg/L target

• Alkalinity: 29 - 30 hours for 90% removal

• Color: 160 - 190 hours for 90% removal


Preliminary Cost Analysis

• As of 2010, Monarch Hill leachate generation ranges from 42 – 96 MG/year (115,000 – 262,000 gal/day)

• Exceedance fees reported at ≈ $350,000 annually, which is ≈ $3.65 - $8.35 per 1,000 gallons

• Investigating the cost of using the optimum catalyst dosage range of 4 - 10 g/L, the most cost efficient dose is 4 g/L.

3/18/2013

8



Costs 42 MG/year 96 MG/year

TiO2 chemical costs (one time only) $289,630 $662,010

2 x 0.2 MG tanks $90,000

2 x 0.3 MG tanks $140,000

UV lamps/ballast/power supply $40,000 $70,000

Pumps/blowers/plumbing/etc. $21,000 $36,000

Total capital cost $440,630 $908,012

Annualized (6%, 20 years) $38,423 $79,179

O&M costs (est. 10% of capital) $44,063 $90,801

Total annual costs $82,486 $169,980

Cost per 1000 gallons $1.96 $1.77

• Original Cost estimate based on lab scale treatment of simulated leachate for 20 hours with 13.3 g/L TiO2



Costs 42 MG/year 96 MG/year

TiO2 chemical costs (one time only) $871,068 $1,991,014

2 x 1.0 MG tanks $1,736,020

2 x 2.5 MG tanks $3,088,180

UV lamps/ballast/power supply $250,000 $500,000

Pumps/blowers/plumbing/etc. $89,000 $136,000

Total capital cost $2,946,088 $5,715,194

Annualized (6%, 20 years) $256,899 $498,365

O&M costs (est. 10% of capital) $294,609 $571,519

Total annual costs $551,508 $1,069,884

Cost per 1000 gallons $13.13 $11.14

• Cost estimate based on pilot scale treatment of real leachate for 200 hours with 4 g/L TiO2


Preliminary Cost Analysis• Current treatment process is not cost efficient and will

require some changes to lower the treatment time.• Increase in UV power (increased intensity and/or

decrease distance from UV source)

• Change the reactor style to mimic continuous flow conditions will speed up the reaction rate

• Chemical additives to optimize the process need to be further researched


Next Step

• Catalyst Recovery• 3 bag sizes (5, 10 and 20 micron) will be tested on

their efficiency in recovering the TiO2 after approximately 8 hours of treatment.

• The goal is to recover at least 80% of the catalyst

• Aeroxide TiO2 P25 is reported to have an average primary size of 21nm


Future Work

• Catalyst Reuse Efficiency

• Refined Cost Analysis

• Understand Alkalinity Dependence

• UV Light Modification


Huddle.net

Acknowledgements

• TAG Members

• Daniel Meeroff, PhD, EI

• Andre McBarnette

• Richard Reichenbach

• Jeff Roccapriore

• Florida Atlantic University

3/18/2013

9


• Do you know of an easy/efficient way to collect the TiO2 nanoparticles for reuse?

• What other chemical constituents of leachate are of interest to you?


Technical Advisory Group Meeting

1. “Reducing The Iron Pollution In Landfill Soils By Using Aeration Wells”

Ahmed Albasri, MSCE CandidateDepartment of Civil, Environmental & Geomatics Engineering



The Problem• Iron is being detected in monitoring wells

downstream of Florida landfills• State Enforceable Secondary Drinking Water Standard

(62-550 FAC) and Groundwater Cleanup Target Level (62-777 FAC) set at 300 µg/L (0.3 mg/L)

• Evaluation monitoring required by 62-701.510(7)(a) if levels are detected significantly above background

• Requires installation of compliance monitoring wells• Requires additional sampling• Stipulates corrective measures (62-780 FAC)

• Pump & treat with filtration, biological treatment, chemical treatment

26

Fe55.845


Sources• Landfill

leachate• Iron liberated

due to the presence of the landfill


Iron from Leachate?


Iron Mobilization in Leachate Plumes• Landfill leachate plume chemistry:

• High oxygen demand• High levels of strongly reduced organic matter • pH 6.5-8 (typical Florida landfill leachate)

• Groundwater chemistry:• Soils high in subsurface iron oxides• Low DO, reducing conditions

• Food source + environmental condtions favor iron-and sulfate-reducing bacteria (Shewanella and Desulfovibrio)• Microbially-mediated liberation of ferrous iron

3/18/2013

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Landfill Leachate• If the source of the elevated iron is landfill leachate,

then we would expect to see:• Other conservative tracers (TDS, chlorides, etc.)• Other leachate contaminants (VOCs, As, etc.)• Dilution effects compared to the measured leachate

water quality

• Caveats:• Variability caused by field sampling methods• Reliability of redox-sensitive parameters • Well construction materials (non-steel)• Variations in landfill construction methods


North Florida Results

Monitoring Well 7S

Monitoring Well 2S

• Townsend 2008

• Timmons et al. 2008

• Wang and Stone 2008


Case Study

• Iron presence was detected in 22 observation wells on 29 April 2008 in North Central Landfill (NCLF) higher than PDWS (Florida Primary Drinking Water Standard) which is 300 µg /L

• High Iron presence exceed the CTL (Clean-up Target Level) which is 3000 µg /L were observed in 15 monitoring wells including compliance wells


NE

SESW


Possible Corrective Measures• Options:

• Either Pump and treat with packed column, sedimentation, membrane filtration system (Sim et al. 2001)

• Excess iron bacteria disinfection

• Lack of iron bacteria microaeration, pH-adjustment, chelation with organic acids, nutrient addition

• Ferrous iron ion exchange or oxidation + filtration or adsorptive filtration or oxidation trenches

• Ferrous + Arsenic advanced oxidation recirculation wells

• Hydrology restore non-reducing conditions


Treatment Method• Soil aeration is one of the successful decontamination processes

used to treat volatiles • Groundwater circulation well (GCW) systems attempt to create a 3-

dimensional circulation pattern in an aquifer by drawing ground water into the well

• The main goal of this system is to oxidize the Iron in the soil from Fe(ll) form to Fe(lll) form, which is insoluble to stop Iron migration with ground water

• The advantage is that treatment of the contaminated groundwater takes place below grade and does not require that it be pumped out the ground

• Another advantage over conventional pump-and-treat is that GCWs induce a groundwater circulation zones that “sweeps” the aquifer• Pump-and-treat systems cause drawdown around the well, leaving

contaminated zones that are not treated

3/18/2013

11


Air

SandFilter

Another Option

• In situ remediation process

• Metals and radionuclides

• Volatiles

• Biodegradables

• Simple to operate

• Rapid

• InexpensiveReactionZone


Groundwater circulation well (GCW)


Objectives

1. To develop a list of viable engineering alternatives for controlling the release of iron in-situ

2. To conduct lab experiments for iron (and possible co-contaminant) removal in-situ using groundwater recirculation well technology


Samples Collection• Boca soil samples were collected

• 4 samples were collected from Polk County Landfill

• The first 2 samples where collected from SE & NE of the site on 05/11/2011

• The second set of 2 were collected from SE & SW on 11/10/2011

• The samples collected after removing the top 15 cm from the soil surface

• The soil has a homogeneous profile

• The samples were kept at room temperature until testing


Aquarium Experiments• GCW model consists of the following parts:

• Transparent glass aquarium of (11.5 × 5.5 × 7.75) inch dimensions

• A prototype of sparging well (vinyl tube ½” outside DIA)

• Two well screens with 4 slits/cm and 1 inch long separated by 1 inch

• Vinyl tube within a tube to create the negative pressure head of the air bubbles which induces circulation

• Gravel filter around the well with #20 Sieve for a diameter of 1.5 inch around the well

• Aquarium Air pump (elite 799) with 1 cubic ft / min flowrate and with pressure of 1.0 PSI


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Test with Boca Soils• For conservative demands the test has started with soil from Boca

Raton to prove the ability of contaminant removal

• Boca soil is sandy as it lies in the Eastern Sandy flatland area according to physiographic region.

• The geographical distribution of the soil in Florida reflects that Boca soil is sposdsol type which has an expected iron content of 300 mg/kg

• Iron reference of 100 mg/L was added to the water and soil in the aquarium

• Two aquarium tests were running simultaneously to obtain replicate results



Results of Boca Soil Tests• Iron concentration found in Boca Raton was close to

the theoretical data (~300 mg/kg) for all samples• Iron removal readings through the 72 - 264 hr

running time show arbitrary numbers as it cannot be decided whether the Iron is in Fe(II) or Fe(III) form as they both can be occur in spectrometric test

• Independent lab results were also inconclusive due to the limitations of the phenanthroline colorimetric method


0

100

200

300

400

500

1 2 3 4

fFe

mg

/Kg

Boca Raton test Results compare with chen.1999

Fe soil test withoutrover

Fe with Rover

Spodosols(0.033*10^4)

0

0.5

1

1.5

2

0 1 2 3 4 6 24 48 54 72

Fe(

C/C

0)

Time (hours)

Iron reading in Boca Soil

Sample1

Sample2


Test for Polk County Soils

• 3 samples for each one of the 2 samples collected in May 11-2011 for Iron digestion Hot Block experiment are in process

• 2 Aquariums of the SE and NW landfill soil which was collected in May 11-2011 are built already

• The 2 which were collected in November are in the drying process


Tests with Polk County Soils

• 4 Aquariums for the soils Collected from Lakeland landfill.

• Same Construction were adopted for Boca tests.

• SE & NE soil samples were sandy profile which enable setting them quickly in their 2 aquariums.

• SE & SW were need further process as they were clay constructed soil.

• Soils had been dried for 24 hour with 100 degree Celsius

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Tests with Polk County Soils

• 4 samples were homogenized with a hammer and added to 2 aquaria

• 94 mg/L Iron has been created FeCl2 with HCl

• 4 Aquaria were saturated with iron for 1 day

• 4 Aquaria tests were started on 10/31/2012



Testing Results

• Spectrophotometer test conducted and samples collected 1, 2, 4, 6, 8 & 12 hours

• The results show fast decreasing after 1 hour of running the experiment in 4 aquaria

• Iron reading were 0.11 - 0.08 mg/L for the 4 test experiments after 1 hour running and keep decreasing through time


0 1 12FE 94.3 0.1195 0.0909

0

50

100

Iro

n

Fe for NE 05/11/11

0 1 12FE 94.3 0.08969 0.05764

0

50

100

Iro

n

Fe for SE 05/11/11

0 1 12FE 94.3 0.08 0.0933

0

50

100

Iro

n

Fe for SW 11/9/11

0 1 12FE 94.3 0.08 0.04

0

50

100

Iro

n

Fe for SE 11/9/11


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Adding Iron to the Samples

• Fast initial degradation of iron soil may play vital role by adsorbing the spiked iron

• To counteract this possibility, iron was saturated in the aquaria to achieve a variance <10 % (steady state) in aqueous iron concentration

• This spiking process took 3-4 weeks• 365+ mg of iron were spiked for each aquarium

• Loading of the aquaria required an additional 4 weeks due to flooding, seepage, and evaporation


Aquarium 1 and 2

• Aquarium 1 (SE 11/09/2011) and 2 (SW 11/09/2011) show less than 10% variance which make them ready to test

Slope = 0.4% Slope = 0.18%


Aquarium 3 and 4

• Aquarium 3 (SE 05/11/2011) and 4 (NE 05/11/2011) still show higher variance, so we are still in the spiking process

Slope = 4.3% Slope = 0.65% Presentation to the HCSHWM Technical Advisory GroupBoca Raton, FL, March 15, 2013

Saturated Aquarium Experimenting• Aquarium 1 and 2 were started on 02/24/2013

• Sampling times were concentrated in the first hour as degradation was expected to occur rapidly


Iron Degradation Experiments


Results

• The GCW process with Aquarium 1 shows rapid degradation in the first 2 hours• kfirst order = 2.4 hr-1; r2 = 0.89

• Aquarium 2 did not show significant changes because the initial iron concentration was much lower than in the 1st aquarium• kfirst order = 0.4 hr-1; r2 = 0.06

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Summary of Findings

• According to the last 2 tests conducted with Polk County soil, they both showed rapid iron removal using GCW technique

• Aquarium 2 needs to be repeated with more spiked iron to confirm

• Further tests for the 2 samples left are going to consolidate the principle targeted to using that technology as remediation solution


Next Steps

• 1. Complete the saturation of the 3rd and 4th aquaria and test them with GCW for iron removal

• 2. Find the design limitation according to the prototype specification and soil features

• 3. Develop a design equation for field implementation

• 4. Analyze the iron speciation


Recommendations

• Utilizing the sparging well (GCW) as treatment technique for contaminated groundwater and soils with elevated iron

• Study soil profile as the technique could vary according to soil characteristics, permeability, and texture which will determine the efficiency of the process


I Have Questions for YOU

• Do you have any knowledge of design equations that govern groundwater circulation well (GCW) systems or sparging wells?

• Do you have any suggestions for an appropriate test method to speciate the forms of iron, Fe(II) and Fe(III), in groundwater and soils?

• Where else is iron reductive dissolution a problem?

• What are the costs associated with remediation of iron dissolution?


TAG Meeting

“Leachate Clogging Project”

Christine Lyons, BSCE CandidateDepartment of Civil, Environmental & Geomatics Engineering



Exciting New Joint Project

• “Critical Examination of Leachate Collection System Clogging at SWA Disposal Facilities”

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Problem Statement

• Calcium carbonate scale buildup in leachate collection system for certain cells causes clogging

• Removing clogs is costly and time consuming

• Private company does the cleanout• $130K + $1200/day for video

• 2.5 months to clean cells 6-16


2012 Jetting Results


2013 Jetting Results


What is in the LCS?

• Primary leachate

• Leak detection (2° liner)

• Gas wells

• Condensate lines

• Class III leachate

• Dyer (closed landfill) leachate

• Cooling water


LCS

• 65 miles of gravity pipe

• Laterals are 60-70 ft apart

• 6-8 inch DIA perforated pipe wrapped in filter cloth

• Pump stations• 250-270 gpm 24/7

• Pump station A is the lowest point in the system

• Forcemain

• Drip lines for gas condensate

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Parameters

• Temperature

• pH

• Specific conductance

• Conductivity

• Salinity

• DO

• COD

• Ammonia

• Color

• Alkalinity

• TSS,TDS,VSS

• Ca, Mg, Fe


11/21/2012 FAU SamplesParameter Cell 6 Leachate

CompositeCell 6 Leak Detection

Gas Condensate

Gas WellsForcemain

pH 6.60 7.17 7.26 7.56

Cond. (mS/cm) 0.49 4.31 1.35 1.05

TDS (mg/L) 2,380 30,000 17,750 5,280

TSS (mg/L) 15 35 57 89

COD (mg/L) 780 3940 6830 3730

Color (PCU) 200 1025 600 200

Alk (mg/L as CaCO3) 1175 675 2750 2725

Ca (mg/L as CaCO3) 470 3310 250 270

Mg (mg/L as CaCO3) 230 180 250 50

NH3-N 364 1644 1250 870


12/10/2012 FAU SamplesParameter Cell 6 Leachate

CompositeCell 6 Leak Detection

Gas Condensate

Gas WellsForcemain

pH 6.53 6.93 7.05 7.57

Cond. (mS/cm) 0.35 4.61 1.24 1.31

TDS (mg/L) 1331 37,020 4190 6510

TSS (mg/L) 14 20 332 46

COD (mg/L) 600 4110 11,190 4040

Color (PCU) 250 350 250 750

Alk (mg/L as CaCO3) 800 575 2250 3275

Ca (mg/L as CaCO3) 420 2990 100 300

Mg (mg/L as CaCO3) 80 790 250 150

NH3-N 208 1432 1592 1026


12/10/2012 FAU SamplesParameter Class 1 Flare Class III +

DyerDyer Cooling

Water

pH 7.16 7.21 7.27 6.88

Cond. (mS/cm) 1.11 0.67 0.64 0.48

TDS (mg/L) 6305 3114 2733 3645

TSS (mg/L) 98 6.1 23 28

COD (mg/L) 9290 820 740 60

Color (PCU) 125 275 250 125

Alk (mg/L as CaCO3) 2200 1350 1850 75

Ca (mg/L as CaCO3) 200 680 440 1710

Mg (mg/L as CaCO3) 230 530 100 200

NH3-N 1232 376 360 10



01/25/13 FAU SamplesParameter Class I

FlareCell 5 Gas F/M

Cell 6 GasF/M

Pump Station D

pH 6.91 7.75 6.07 6.90

Cond. (mS/cm) 8.5 17.3 54.4 9.4

TDS (mg/L) 5200 37,020 4190 5700

DO (mg/L) 3.81 5.07 5.04 1.67

Temperature (°C) 28.0 24.2 23.2 28.5

TSS (mg/L) -- -- -- --

COD (mg/L) 4450 4130 63,400 2760

Color (PCU) -- -- -- --

Alk (mg/L as CaCO3) 1075 2100 4700 1850

Ca (mg/L as CaCO3) 100 160 11400 --

Mg (mg/L as CaCO3) 170 200 700 --

NH3-N (mg/L as N) 1090 1660 5130 550

Fe (mg/L) 6.15 18.8 530 --

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01/25/13 FAU SamplesParameter Cell 7

LeachateCell 7 Leak Detection

Cell 10 Leachate

Cell 10 Leak Detection

pH 7.40 7.37 7.17 7.42

Cond. (mS/cm) 46.78 43.33 43.23 26.62

TDS (mg/L) 28,210 28,160 25,890 16,880

DO (mg/L) 4.2 5.6 1.1 1.9

Temperature (°C) 29.0 24.2 29.6 26.4

TSS (mg/L) -- -- -- --

COD (mg/L) 4050 3600 3760 3400

Color (PCU) -- -- -- --

Alk (mg/L as CaCO3) 3000 4675 5800 7300

Ca (mg/L as CaCO3) 650 150 3200 --

Mg (mg/L as CaCO3) 350 1000 500 --

NH3-N (mg/L as N) 2440 2630 2840 2570

Fe (mg/L) -- -- -- --Presentation to the HCSHWM Technical Advisory Group

Boca Raton, FL, March 15, 2013

01/25/13 FAU SamplesParameter Cell 12

LeachateCell 12 LDS

Cell 11 Leachate

Cell 11 LDS

Cell 9 Leachate

Cell 9 LDS

pH 7.17 7.09 6.81 7.33 7.25 7.34

Cond. (mS/cm) 22.1 12.6 48.1 21.3 40.9 28.4

TDS (mg/L) 12,990 7,995 27,700 14,130 23,850 17,850

DO (mg/L) 1.13 1.76 1.15 1.97 2.20 2.11

Temperature (°C) 30.6 26.3 31.8 24.0 31.1 26.9

TSS (mg/L) -- -- -- -- -- --

COD (mg/L) 2290 920 2760 2780 5200 4220

Color (PCU) -- -- -- -- -- --

Alk 4700 2850 3900 5700 5450 7200

Ca -- -- -- -- -- --

Mg -- -- -- -- -- --

NH3-N (mg/L as N) 1630 1240 1440 2170 2490 2820

Fe (mg/L) -- -- -- -- -- --


April 24, 2012 CDM Letter ReportParameter Cell 6

Leachate Composite


Gas Condensate

Gas WellsForcemain

pH 7.12 6.82 6.50 6.96

DO (mg/L) 3.77 (34°C) 1.45 (32°C) 1.24 (35°C) 0.40 (37°C)

Salinity (ppt) 20 21 4.2 20

ORP (mV) -182 -30 -114 -188

Conductivity(mS/cm)

38 31 9 39

TDS (mg/L) 27,000 23,000 2900 30,000

TVS (mg/L) 8,600 5200 1800 17,000

TS (wt%) 2.98 2.47 0.36 3.64

Foaming No No Yes YesPresentation to the HCSHWM Technical Advisory Group

Boca Raton, FL, March 15, 2013

April 2012 InorganicsParameter Cell 6

LeachateComposite


Gas Condensate

Gas WellsForcemain

Chloride 18,000 14,000 760 12,000

TP 13 7.1 7.2 12

Sulfate 630 570 560 990

Alkalinity 6100 780 2700 9900

Ammonia 11 5 5 14

TKN 15 12 14 20

NO3 + NO2 0.7 1.7 0.7 1.1

TN 16 14 15 21

TOC 4200 390 2100 12,000


April 2012 Metals and VFAsParameter(mg/L)

Cell 6 LeachateComposite


Gas Condensate

Gas WellsForcemain

Calcium 920 1300 34 1400

Magnesium 150 110 29 230

Sodium 5600 4500 500 5400

Total Fe 75 13 3.0 270

Soluble Fe 65 6.0 3.2 21


NaOH Precipitation

• Rock formation occurred in certain samples with the addition of NaOH

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NaOH Precipitation

• Moles of NaOH required to form rock correlates with alkalinity:


Sampling Plan• 23 samples @ 3 times (to apply statistics)

• LCS Class I – Cells 5 to 12 (8 samples)• LDS Class I – Cells 5 to 12 (8 samples)• Dyer Road Landfill leachate (1 sample)• Liquid from saturated gas wells (2 samples)

• Cell 5 and 6

• Class III leachate (2 samples)• Pump Stations C & D

• Condensate from Class I flare (1 sample)• Cell 8

• Blowdown water from WTE plant (1 sample)


Future Plans

• Three months of continuous sampling is expected to happen this summer

• Analyze the water quality data for calcium carbonate precipitation potential (Langelier’s Index, Ryznar Index, etc.)

• Demonstration testing on site


Questions?


Questions for You

• Do you have any suggestions for possible solutions?

• Have you heard of this happening at other facilities?

• What other experiments would you suggest?


Contacts

• Mark Eyeington

• Ron Schultz, Utilities Manager• Gas and leachate, electrical, and pump stations

• Tim Townsend

• Kevin Kohn

• Christine Lyons

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Sponsors


116

website: http://labees.civil.fau.edu

technical advisory group - florida atlantic universitylabees.civil.fau.edu/technical advisory...

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