Delaware’s venture into modern landfills.

Delaware’s venture into modern landfills.

N. C. Vasuki, P.E., DEECEO, Delaware Solid Waste Authority

www.dswa.com

N. C. Vasuki, P.E., DEECEO, Delaware Solid Waste Authority

www.dswa.com

IntroductionIntroduction■ Landfills provide the foundation for the State’s

solid waste management program■ In 1980 the first geomembrane (30 mil pvc) lined

landfill cell (9 acres) was constructed■ In 1982, a second cell (18 acres) was added.■ Leachate treatment became an issue.■ Dr. Fred Pohland’s research at Georgia Tech

appeared to provide a solution for our problem.■ Attempts were made to introduce leachate into

both cells.

■ Landfills provide the foundation for the State’s solid waste management program

■ In 1980 the first geomembrane (30 mil pvc) lined landfill cell (9 acres) was constructed

■ In 1982, a second cell (18 acres) was added.■ Leachate treatment became an issue.■ Dr. Fred Pohland’s research at Georgia Tech

appeared to provide a solution for our problem.■ Attempts were made to introduce leachate into

both cells.

Leachate recirculationLeachate recirculation■ Absence of prescriptive regulations allowed us

to experiment with various methods.■ Vertical recharge wells (perforated concrete

manhole sections) appeared to work.■ More wells were added and leachate export for

external treatment was reduced.■ Gas production also increased. Based on the

experience gained, we started improving our design.

■ Absence of prescriptive regulations allowed us to experiment with various methods.

■ Vertical recharge wells (perforated concrete manhole sections) appeared to work.

■ More wells were added and leachate export for external treatment was reduced.

■ Gas production also increased. Based on the experience gained, we started improving our design.

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Property Boundary

Shallow Pleistocene

Pleistocene

Frederica Aquifer

Cheswold Aquifer

Gas Migration Monitoring Well

Water Supply Well

Irrigation Well

Surfacewater Sampling Point

Single Leachate Sampling Point

Duel Primary Leachate/Secondary

Detection Liquid Monitoring Point

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LEGEND

Fig. 4: Sandtown Landfill - Locations of Groundwater, Leachate, and Surfacewater Monitoring Points

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Area C-D

Jones Crossroads LandfillJones Crossroads Landfill■ DSWA’s southern landfill■ Four separate cells, Cells 1 through 4■ Leachate collected and pumped to tanks, hauled

by truck off-site. Limited volume recirculated.■ Landfill Gas collected and flared.■ Dead chickens disposal (emergency service)

created a hydrogen sulfide problem.

■ DSWA’s southern landfill■ Four separate cells, Cells 1 through 4■ Leachate collected and pumped to tanks, hauled

by truck off-site. Limited volume recirculated.■ Landfill Gas collected and flared.■ Dead chickens disposal (emergency service)

created a hydrogen sulfide problem.

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LEGEND

Shallow Piezometers

Property Boundary

Shallow Columbia Wells

Deep Columbia Wells

Manokin Wells

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Surfacewater Sampling Point

Irrigation Wells

Single LeachateSampling Point

Primary Collection& Secondary DetectionMonitoring Point

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Fig.8 Jones Crossroads Landfill - Locations of Groundwater, Leachate, and Surfacewater Monitoring Points

Liner CostsLiner Costs

$3.77 $3.77 -- fPPfPP$3.99 $3.99 –– HDPEHDPECell 4Cell 4$6.45 $6.45 –– fPPfPP$4.31 $4.31 –– HDPEHDPEArea EArea E$5.70$5.70Cell 3Cell 3US$/smUS$/smCellCell

Liner Leakage RatesLiner Leakage Rates

None, to dateNone, to date12.112.1GeonetGeonetCell 4Cell 4102,237102,2377.47.413.213.2GeonetGeonetArea EArea E

62,42962,42915.915.99.79.7GeonetGeonetCell 3Cell 3813,056813,056115.6115.68.98.9SandSandArea DArea D

Total Total amount of amount of

liquid liquid collectedcollected

Liters/Liters/ha/dayha/day

Size of Size of cell (ha)cell (ha)

Type of leak Type of leak detection detection systemsystem

CellCell

Cap Costs & Leachate GenerationCap Costs & Leachate Generation

7,3367,336NANA80,25080,250Pigeon pt.Pigeon pt.Soil +PhytoSoil +Phyto

7067066,7756,775243,800243,800Jones crossJones crossCell 2Cell 2

6506502,7322,732324,900324,900Jones crossJones crossCell 1Cell 1

Leachate GenLeachate GenLiters/ha/dayLiters/ha/day

ACAC

Leachate GenLeachate GenLiters/ha/dayLiters/ha/day

BCBC

Cap Cost Cap Cost $/ha$/ha

LandfillLandfill

Cap costs & Leachate GenerationCap costs & Leachate Generation

8938934,0814,081175,700175,700SandtownSandtownCell DCell D

1,3181,3183,7103,710192,100192,100SandtownSandtownCell CCell C

3,7753,7753,4263,42667,80067,800SandtownSandtownCells A&BCells A&B

Leachate GenLeachate GenLiters/ha/dayALiters/ha/dayA

CC

Leachate GenLeachate GenLiters/ha/dayLiters/ha/day

BCBC

Cap costCap cost$/ha$/ha

LandfillLandfill

Current trends in leachate Current trends in leachate recirculation in Delawarerecirculation in Delaware

■■ Our new landfill cells use Horizontal pipes to Our new landfill cells use Horizontal pipes to introduce leachate into the solid waste mass.introduce leachate into the solid waste mass.

■■ The most promising method appears to be The most promising method appears to be the “Horizontal Injection Trenches” or HIT’s.the “Horizontal Injection Trenches” or HIT’s.

■■ The volume of leachate required to saturate The volume of leachate required to saturate the solid waste can be estimated using the the solid waste can be estimated using the build up of pressure as a guide.build up of pressure as a guide.

■■ The trench is allowed to rest and later the The trench is allowed to rest and later the same pipe can be used to extract LFG. same pipe can be used to extract LFG.

Data CollectionData Collection

■■ We are attempting to add to our already We are attempting to add to our already large data base with specific measurements large data base with specific measurements of LFG production from various cells. This of LFG production from various cells. This may help in improving our understanding of may help in improving our understanding of the behavior of landfill cells over a period of the behavior of landfill cells over a period of time.time.

■■ One must be patient in this respect and One must be patient in this respect and persistent in data collection. persistent in data collection.

What should USEPA do to help What should USEPA do to help improve landfills?improve landfills?

■■ Modify landfill cap requirements to Modify landfill cap requirements to allow more experimentation.allow more experimentation.

■■ For landfill cells with double liners, For landfill cells with double liners, phyto caps should be allowed.phyto caps should be allowed.

■■ Establish uniform criteria for collection Establish uniform criteria for collection of leachate and LFG data from all of leachate and LFG data from all landfills in the nation.landfills in the nation.

What else can USEPA do to help What else can USEPA do to help reduce emissions of LFG?reduce emissions of LFG?

■■ Expedite Title V permit issuance. It is Expedite Title V permit issuance. It is taking too long!taking too long!

■■ Actively support research to develop Actively support research to develop criteria for determining the end of the criteria for determining the end of the closure period of landfills.closure period of landfills.

■■ Actively support upgrading the training Actively support upgrading the training programs for landfill operators.programs for landfill operators.

Delaware’s venture into modern landfills.IntroductionLeachate recirculationJones Crossroads LandfillLiner CostsLiner Leakage RatesCap Costs & Leachate GenerationCap costs & Leachate GenerationCurrent trends in leachate recirculation in DelawareData CollectionWhat should USEPA do to help improve landfills?What else can USEPA do to help reduce emissions of LFG?