Performance Based System

for Determining Post Closure Care (PCC) at Florida MSW Landfills

Southwest Landfill, Alachua County, Florida

Dr. Debra ReinhartAsawari Kulkarni

Outline Performance based methodology Timeline Project status Groundwater Module

Groundwater monitoring well locations Statistical comparison Groundwater data analysis: VOC Metal analysis and results Summary

Next

Performance Based Methodology Developed by EREF (Geosyntec

contractor) Comprised of four modules:

Leachate Module Groundwater Module Landfill Gas Module Cap Module

1988

1989

1990

1991

1992

1993

2000

1999

1998

1997

1994

1996

1995

Operation Began: Constructed and started accepting waste

Horizontal Injection for Leachate Recirculation Initiated

Recirculation via Infiltration Ponds

Started tires separation/ shredding and recycling

Final Closure

2001

2002 LFGTE initiatedSite history and timeline

Performance Based Methodology Leachate Module

Analysis of leachate monitoring data Data from 1993-2007 For 90% ND, reduce monitoring

frequency and then discontinue

Performance Based Methodology: Leachate Module Outcomes Organic contaminants: Reduce

and then discontinue monitoring Declining and approaching MCL (e.g.

acetone) Detected always below MCL ( e.g. styrene

or naphthalene) Following a significant reducing trend

and are below MCL ( e.g. toluene, xylene)

Performance Based Methodology: Leachate Module Outcomes Trends followed by metal

contaminants: Reduce and discontinue monitoring for

metals always BDL ( only copper) Continue monitoring for arsenic, iron,

chromium: Concentration and mass variations depending on the leachate flows

Project Status

Leachate Module Groundwater Module Landfill Gas Module Cap Module

Groundwater Module Analysis of historical groundwater

monitoring data Helps in making a decision on

optimizing/terminating current groundwater monitoring plan during PCC

Data obtained from Southwest Landfill consultants, Jones, Edmunds & Assoc.

EPA Recommended Comparison Options

Comparison with historical data from same well : Intra-well comparisons

Comparison With background wells : Inter-well Comparison

Comparison with MCL

Control Charts

Confidence Interval Method

Tolerance Interval

Test of proportions

ND > 50%?Yes

No

No

No

Data

Test of proportions Confidenc

e Interval (CI)

Are data normal?

Yes

Are Log data normal?

Yes

Normal CI

Log-normal CI

Non-Parametric Approach

Non-Para CIYes

Groundwater Monitoring Data Monitoring data available from

1994-2007 Around 200 parameters are

monitored every year CHEMSTAT is used for statistical

comparisons Minitab 15 for graphical

representations

Groundwater monitoring data√Statistical analysis tools √

Frequently Detected Contaminants: VOCs

1,1-Dichloroethane (109)

1,2-DICHLOROBENZENE (9)

1,4-DICHLOROBENZENE (173)

ACETONE (8)

BENZENE (10)

C,1-2,Dichloroethene (30)

CHLOROBENZENE (129)

CHLOROETHANE (3)

CHLOROFORM (2)

CHLOROMETHANE (12)

DICHLORODIFLUOROMETHANE (7)

METHYLENE CHLORIDE (5)

TETRACHLOROETHENE (16)

VINYL CHLORIDE ( 42)

0 20 40 60 80 100 120 140 160 180

C, ug/L

VOC's Detected at SWLF

Number of Detects

VOCs detected at SWLF

Frequently Detected VOC: Acetone Found only in

well SW-2D Detected

before year 2000

May be due to 7 acres Class III disposal area to the south

1/1/20031/1/20021/1/20011/1/20001/1/19991/1/19981/1/1997

400

300

200

100

0

Date

C,

ug

/L

Acetone : SW-2D

Location of well SW-2D: Acetone

Frequently detected VOC: 1,4-dichlorobenzene

Wells SW-4D, SW-7D and SW-10D

Found in Compliance wells

Frequently detected VOC: 1,4-dichlorobenzene

1/1/20081/1/20061/1/20041/1/20021/1/20001/1/19981/1/19961/1/1994

20

15

10

5

0

Date

C, ug/L

SW-4D * DATE1SW-7D * DATE2SW-10D * Date

Variable

1,4-Dichlorobenzene : SWLF

Frequently detected VOC: Chlorobenzene Second most

frequently detected contaminant

Detected in SW-4D and SW-10D

Probably comes from degradation of dichlorobenzene in anaerobic conditions

Increasing trend

1/1/20081/1/20061/1/20041/1/20021/1/20001/1/19981/1/19961/1/1994

5

4

3

2

1

Date

C,

ug

/L

SW-10D * Date

SW-4D * D

Variable

Chlorobenzene

Frequently Detected VOC: Vinyl chloride

1/1/20081/1/20061/1/20041/1/20021/1/20001/1/19981/1/19961/1/1994

5

4

3

2

1

D2

C, ug/L

1

SW-4D : Vinyl Chloride

Frequently Detected VOC: Vinyl chloride Found consistently in well SW-4D MCL – 1 ug/L Vinyl chloride concentration > MCL May come from dechlorination of chlorinated

ethenes under anaerobic conditions VC degrades better aerobically as compared

with anaerobic conditions Declined after 2001 Significant contamination when compared

with MCL and background wells Never detected in leachate ( always BDL)

Less frequently detected VOC 1,2-dichlorobenzene Benzene C-1,2-dichloroethene Chloroethane Chloroform Chloromethane Dichlorodifluoromethane Methylene chloride Tetrachloroethene

Recommendations for VOCs Reduce, then

discontinue monitoring frequency:

1,2-dichlorobenzene Benzene C-1,2-dichloroethene Chloroethane Chloroform Chloromethane Dichlorodifluoromethan

e Methylene chloride Tetrachloroethene

Recommendations for VOCs Continue monitoring for vinyl

chloride Consistent detection frequency Above MCL

Metal Analysis: Metal Detection Frequency

Antimony

Arsenic

Barium

Cadmium

Chromium

Cobalt

Copper

Iron

Lead

Mercury

Nickel

Zinc

0 100 200 300 400 500 600

Total Detects

Meta

ls

METAL SUMMARY

Metal TME Leachate

Range

GW Range, µg/L

MCL, µg/L

Up Down

Antimony 398 1-41 0.7-2.5 0.7-9 6

Arsenic 764 0-280 1.43-27

1.2-32 10

Barium 401 19-50 2-21 1-420 2000

Cadmium 761 6-14 0.409 0.18-13 5

Chromium

761 0-190 16-18 1.25-53 100

Cobalt 374 0.2-250 BDL 0.4-40 NA

Copper 421 11-3100 2-15 0.6-110 1300

Lead 761 1.5-50 3.6-5.8 1-49.2 15

Mercury 760 0.035-1.5

0.1-0.6 0.087-1.6

2

Nickel 397 97-780 4-14 0.7-72 100

Zinc 410 25-500 1.4-110

1-1300 NA

Metal Recommendation

Reduce, then discontinue metal monitoring frequency:

Antimony Chromium Copper Barium Nickel Cobalt Mercury

1/1/20081/1/20061/1/20041/1/20021/1/20001/1/1998

9

8

7

6

5

4

3

2

1

0

Date

C, ug/L

SW-5D * D13SW-6D * D15SW-7D * D16SW-8D * D17SW-9D * D18SW-P2 * D20SW-P3 * D21SW-P5 * D22

SW-2D * D1SW-3D * D2SW-13D * D4SW-10D * D5SW-11D * D6SW-15D * D7SW-1DN * D8SW-1SN * D9SW-4D * D12

Variable

Antimony Concentration in Groundwater Monitoring Wells

1/1/20051/1/20001/1/19951/1/1990

100

80

60

40

20

0

Date

C, ug/L

100

Chromium : SW-11D

1/1/20051/1/20001/1/19951/1/1990

2000

1500

1000

500

0

Date

C, ug/L

2000

SW-2SN * D11SW-3SN * D12SW-4D * D13SW-5S * D15SW-6D * D16SW-7D * D17SW-8D * D18SW-9D * D19SW-9S * D20SW-P3 * D22

SW2D * D1

SW-P5 * D23

SW-3D * D2SW-P1 * D3S-13D * D5SW-10D * D6SW-11D * D7SW-15D * D8SW-1DN * D9SW-1SN * D10

Variable

Barium : SWLF

1/1/20081/1/20061/1/20041/1/20021/1/20001/1/19981/1/1996

100

80

60

40

20

0

Date

C, ug/L

100

SW-3SN * D10SW-4D * D11SW-5D * D12SW-5S * D13SW-6D * D14SW-7D * D15SW-8D * D16SW-9S * D18SW-P2 * D19SW-P3 * D20

SW-2D * D1

SW-P5 * D21

SW-3D * D2SW-13D * D3SW-10D * D4SW-11D * D5SW-15D * D6SW-1DN * D7SW-1SN * D8SW-2SN * D9

Variable

Nickel Distribution at SWLF GW Monitoring Wells

1/1/20081/1/20061/1/20041/1/20021/1/20001/1/19981/1/1996

40

30

20

10

0

Date

C,

ug

/L

SW-9S * D10SW-P2 * D11SW-P5 * D12

SW-13D * D1SW-10D * D2SW-1SN * D3SW-2SN * D4SW-3SN * D5SW-4D * D6SW-5S * D7SW-7D * D8SW-8D * D9

Variable

Cobalt Distribution at SWLF

1/1/20051/1/20001/1/19951/1/1990

2.0

1.5

1.0

0.5

0.0

Date

C,

ug

/L

2SW-4D * D11SW-5D * D12

Variable

Mercury: SW-4d & SW-5D

Metal Recommendation

Continue monitoring for: Arsenic Cadmium Lead

1/1/20081/1/20061/1/20041/1/20021/1/20001/1/19981/1/1996

14

12

10

8

6

4

2

0

Date

C, ug/L

5

SW-9D * D19SW-9S * D20SW-P2 * D21SW-P5 * D23

SW-10D * D6SW-11D * D7SW-15D * D8SW-1DN * D9SW-1SN * D10SW-4D * D13SW-5S * D15SW-7D * D17SW-8D * D18

Variable

Cadmium Distribution at SWLF Groundwater Monitoring Well

1/1/20051/1/20001/1/19951/1/1990

30

25

20

15

10

5

0

Date

C, ug/L

10

SW-2SN * D9SW-3SN * D10SW-4D * D11SW-5D * D12SW-5S * D13SW-6D * D14SW-7D * D15SW-8D * D16SW-9D * D17SW-9S * D18

SW 2D * D

SW-P2 * D19

SW-3D * D1SW-P1 * D2SW-12D * D3SW-13D * D4SW-11D * D5SW-15D * D6SW-1DN * D7SW-1SN * D8

Variable

Arsenic Scatter in Groundwater Monitoring Wells

1/1/20051/1/20001/1/19951/1/1990

50

40

30

20

10

0

Date

C, ug/L

15

Lead : SW-11D

Metal Recommendation Reduce, then discontinue

monitoring of metals at wells: SW-9D SW-7D Sw-12D SW-P1 SW-2D

Metal Recommendation Sampling

private wells offsite but down-gradient to track potential transport of heavy metals

Summary

Analysis of groundwater monitoring data completed

Future monitoring limited to few metals and VOCs

5 monitoring wells can be eliminated from metal monitoring

Off-site monitoring for metals

Next Landfill gas

module Landfill gas

quality and quantity

Impact on human health and environment

Thank you