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S.W. Ottawa County Landfill
Strategy for Containment and Treatment of Contaminated Groundwater
Barbara Marczak, P.E., Project Manager, P&N
Joe Hebert, Chief Operator, OC DPU
August 11, 2010
Landfill Operation
� 1968 – Landfill Constructed
� 1968 - 1980 – Site in Operation (“State of the Art”)
� 1979 – Groundwater contamination discovered
� 1980 – Site Closed
� 1981 – Site Capped
� 1983 – NPL Registered (SUPERFUND)
GW Investigation & Cleanup
� 1979-2009 – Groundwater Investigation� 1987 – Purge & Treatment System Installed� 1992 – 1994 - More wells and treatment added� 1996 – Proposed upgrades� 2003 – Watermainextended Lakeshore Drive� 2006 – New landfill cover� 2008 – New purge wells� 2009 – Modified treatment system
GW Contamination Investigation
� 1979-2009 – Installation of 115 Monitor Wells
� Basic Hydrogeology1. Unconfined Aquifer
2. Groundwater occurs 5 to 25 feet below ground
3. Fine to Coarse Sand, Surface to 40-50 feet
4. Silt/Clay 40-50 feet deep
5. Hydraulic Gradient: 0.004 ft/ft
6. GW Flow Direction: S.W. then West – 1-3ft/day
GW Contamination Investigation
� Contamination
� Indicator Parameters: Specific Conductance & Iron� Primary Contaminants: Volatile Organic
Compounds (ppb range)� VOC contamination is largely gone within 500 to
1,000 feet of the landfill� Elevated iron seen further out as a result of
biodegradation of VOCs through iron reduction� No VOCs above health based drinking water criteria
except next to landfill
SWOCLF Contamination Plume
Purge wells and Pipelines
1987 Groundwater Remediation
I. Purge Wells● 7 purge wells – 2 near landfill, 5 downgradient
● 3 purge wells added in 1992
II. Treatment System (1 MGD)� Iron Removal
1. Oxidation with Potassium Permanganate2. Filtration
� VOC Removal1. Carbon Adsorption
2006-2008 Remediation Improvement
III. Groundwater Remediation ($1,800,000)
� Installed 4 new purge wells to improve capture of contaminants.
� The only current wells that exceed the NPDES permit for discharge are next to the landfill
III. Groundwater Remediation� Benefits
� Reduced flow to treat by one-half� Capture and treat twice as much contamination� Reduced maintenance on purge wells� Capture more contaminated groundwater
2006-2008 Remediation Improvement
Design Criteria
PARAMETERS
Flow rate (gpm)
Iron (mg/l)
Benzene (µg/l)
Chlorobenzene (µg/l)
Ethyl Ether (µg/l)
Tetrahydrofuran (µg/l)
Influent Pre-upgrade
300--700
9
9
11
12
9
Proposed
500
Conc.
25
22
40
20
15
-30%
Mass
+400%
+400%
+400%
+400%
+400%
Design Criteria
PARAMETERS
Flow rate (gpm)
Iron (mg/l)
Benzene (µg/l)
Chlorobenzene (µg/l)
Ethyl Ether (µg/l)
Tetrahydrofuran (µg/l)
Effluent
500
Conc.
<0.3
5
5
none
none
NPDES
Conc.
5
5
5
none
none
DW
Conc.
0.3
5
100
1,500
95
Feasibility / Pilot Testing
•Treatment Options / Costs
•Pilot testing
2006-2008 Remediation Improvement
III. Groundwater Remediation� Improved the treatment system. (.72 MGD)
� Using aeration for oxidation to reduce chemical use and cost.
� Added a new system for iron removal: flocculation, settling, & filtration.
� No changes to carbon adsorption for VOC removal.� System is automated to run with no operator
present
Process Schematic
Oxidation
DeloachIndustries aeration and detention unitInduced draft aerator @ 3,125 CFM+ 15K gal. detention tank (30 minutes)
Purpose� Convert Iron from dissolved Fe2+ (Ferrous) to Fe3+ (Ferric)� 100% conversion of Iron is needed. � Partial removal of organics expected
Added 60 cfmFine Bubble Diffusion within detention tank
Iron Conversion
0
5
10
15
20
Influent Aeration Aeration +KMnO4
NaMnO4
Iron
Con
c.
(mg/
l)
FerricFerrous
Iron Conversion
0
5
10
15
20
Influent Aeration Aeration +KMnO4
NaMnO4
Iron
Con
c.
(mg/
l)
FerricFerrous
45% Conversion
Iron Conversion
0
5
10
15
20
Influent Aeration Aeration +KMnO4
NaMnO4
Iron
Con
c.
(mg/
l)
FerricFerrous
71% Conversion
Iron Conversion
0
5
10
15
20
Influent Aeration Aeration +KMnO4
NaMnO4
Iron
Con
c.
(mg/
l)
FerricFerrous
100% Conversion
Chemical Oxidation
� Approx. 0.5 lb oxidant to 1 lb Fe2+
� Complete iron conversion from Fe2+ to Fe3+
� 108 lbs/day Fe2+
� KMnO 4 @ $4.75 / lb ($94,000 year)� NaMnO4 @ $0.95 / lb ($19,000 year)
O = Mn - O- Na+
O =
O =
Flocculation and Settling
� ParksonLamella plate settler (.72 MGD)� Primary Settling and Removal of TSS and Fe3+
� Design loading rate: 0.55 gal/ft2/min.� Aeration caused poor performance!
� Coagulant optimization and testing• Aluminum Sulfate @ > 60 mg/l ($26,000 year)• *Polyaluminum hydroxylchlorosulfate @ 40 mg/l• ($24,000 year)
� Polymer optimization� Anionic polymer w/Alum @ 5 mg/l ($16,000 year)� Anionic polymer w/poly Al @ 1 mg/l ($3,200 year)
Filtration
� ParksonDynasandDSF-100 SBTF• Removal of TSS and Fe3+
• 92 ft2 surface area• Design loading rate: 5.43 gal/ft2/min.
• Sand media: Effective size 1.2mmUniformity Coefficient = 1.5
• 40 inch bed depth
• Continuous backwash without interrupting flow
• <0.3 ppmFe3+ performance requirement
BenefitsBenefits••Continuous (moving bed) BackwashContinuous (moving bed) Backwash••Better depth filtrationBetter depth filtration
Constant Constant headlossheadlossContinuous backwashContinuous backwash
••Low mechanical & hydraulic energyLow mechanical & hydraulic energyrequirementsrequirements
No redundancy req.No redundancy req.No costly ancillary supportNo costly ancillary support
••Process: CounterProcess: Counter--current separationcurrent separation
DynaSandDynaSand®® FilterFilter
UpflowUpflow
Settling and FiltrationPost Oxidation
0
10
20
30
40
50
60
Influent Lamella Dynasand
TS
S /
Fe3+
mg/
l
TSSFerric
Settling and FiltrationPost Oxidation
0
10
20
30
40
50
60
Influent Lamella Dynasand
TS
S /
Fe3+
mg/
l
TSSFerric
73% removal
81% removal
Settling and FiltrationPost Oxidation
0
10
20
30
40
50
60
Influent Lamella Dynasand
TS
S /
Fe3+
mg/
l
TSSFerric
47% removal (step)
85% removed overall
75% removal (step)
95% removed overall
Carbon Adsorption
� Effective VOC Removal
� 20,000 lbs carbon each� Series flow configuration
Volatile Organic Compounds
0
10
20
30
40
50
60
70
Influ
ent
Aer
atio
n +
Filt
ratio
n
NaM
nO
4 +
Filt
ratio
n
Car
bo
nE
fflu
ent
VO
C
Con
c. (
µg/
l)
TetrahydrofuranEthyl EtherBenzeneChlorobenzene
0
10
20
30
40
50
60
70
Influ
ent
Aer
atio
n +
Filt
ratio
n
NaM
nO
4 +
Filt
ratio
n
Car
bo
nE
fflu
ent
VO
C
Con
c. (
µg/
l)
TetrahydrofuranEthyl EtherBenzeneChlorobenzene
49% removal
ND
Volatile Organic Compounds
100% removal
0
10
20
30
40
50
60
70
Influ
ent
Aer
atio
n +
Filt
ratio
n
NaM
nO
4 +
Filt
ratio
n
Car
bo
nE
fflu
ent
VO
C
Con
c. (
µg/
l)
TetrahydrofuranEthyl EtherBenzeneChlorobenzene
ND
Volatile Organic Compounds
100% removal
Conclusions
�Effective aquifer capture through hydro geological modeling and testing
�Pilot testing always an invaluable tool
�Micro bubbles will prevent proper settling of floc
�Ensure strict manufacturer performance guarantees