IP Library Granted Patent US 7,955,419
Granted Patent B2
US 7,955,419 · App. 11/878,586 · Granted Jun 7, 2011

System and method for treating landfill gas using landfill leachate

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Quick Facts
Patent No.
US 7,955,419
App. No.
11/878,586
Granted
Jun 7, 2011
Kind
B2
Abstract

Embodiments of the present invention are directed to systems and methods for treating landfill gas using landfill leachate. In one embodiment of the present invention, a method includes receiving landfill leachate from at least one of a plurality of sources, and pretreating the landfill leachate to adjust at least one chemical property of at least one component of the landfill leachate. The leachate contacts landfill gas, so that at least one component of the landfill gas chemically reacts with at least one component of the landfill leachate to form a spent landfill leachate and a treated landfill gas. The method also includes recycling a first portion of the spent landfill leachate, recirculating a second portion of the spent landfill leachate to at least one of the plurality of sources, and subjecting the treated landfill gas to flare.

Claims (14)

1. A method of treating landfill gas using landfill leachate, comprising: treating landfill leachate using a treatment unit; contacting the treated landfill leachate with extracted landfill gas in a landfill gas recapture device, distinct from a landfill mass, the landfill gas comprising at least two components, wherein at least one component of the landfill gas chemically reacting with the landfill leachate to form a spent landfill leachate and a treated landfill gas; recirculating a first portion of the spent landfill leachate to the landfill gas recapture device; and subjecting the treated landfill gas to flare in a flash chamber.

2. The method of claim 1 , further comprising storing landfill leachate in a storage unit.

3. The method of claim 1 , further comprising heating the treated landfill leachate using a reheater.

4. The method of claim 1 , further comprising recycling a second portion of the spent landfill leachate to a source of the landfill leachate, using a pump.

5. The method of claim 1 , wherein the landfill gas recapture device comprises at least one vertical column for directing landfill leachate in a downward direction in a counter-current manner.

6. The method of claim 1 , further comprising condensing leachate vapors from the landfill gas recapture device.

7. A method for removing hydrogen sulfide from landfill gas, comprising: treating the landfill leachate with at least one of a plurality of enzymes, wherein a pH sensor is attached to a treatment unit to determine the pH level of the leachate in the treatment unit; facilitating absorption of hydrogen sulfide in the landfill gas extracted from a landfill by the treated landfill leachate from the treatment unit, using a landfill gas recapture device, distinct from a landfill mass; introducing the landfill gas into the landfill gas recapture device using a nozzle; withdrawing a first portion of spent landfill leachate laden with absorbed hydrogen sulfide from the landfill gas recapture device, using a first pump; regenerating a first portion of the spent landfill leachate laden with absorbed hydrogen sulfide, wherein a pH sensor is attached to the recirculation unit to determine the pH level of the leachate in the recirculation unit, using a recirculation unit; recycling the regenerated landfill leachate from the recirculation unit to the landfill gas recapture device, using a second pump; and subjecting at least a portion of the landfill gas from the landfill gas recapture device to flashing, using a flash chamber.

8. The method of claim 7 , further comprising disposing a second portion of the spent landfill leachate laden with absorbed hydrogen sulfide to a landfill, using a third pump.

9. The method of claim 7 , further comprising introducing additives to a first portion of spent landfill leachate in the recirculation unit.

10. The method of claim 7 , further comprising storing the at least one of the plurality of enzymes in a treatment chemical storage unit.

11. The method of claim 7 , wherein at least one of the enzymes adjusts the pH of the landfill leachate in accordance with the pH sensor coupled to the treatment unit.

12. The method of claim 7 , wherein the pH of the first portion of the spent leachate is mixed with the leachate in the treatment unit in accordance with the pH sensor coupled to the recirculation unit.

13. The method of claim 7 , wherein the landfill gas recapture device comprises at least one vertical column for directing landfill leachate in a downward direction in a counter-current manner.

14. The method of claim 7 , further comprising condensing leachate vapors from the landfill gas recapture device.

Assignments (9)
SECURITY INTEREST Recorded May 14, 2018
From: CASELLA WASTE SYSTEMS, INC.
To: BANK OF AMERICA, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 045798/0749 →
RELEASE OF SECURITY INTEREST Recorded May 14, 2018
From: BANK OF AMERICA, N.A., AS ADMINISTRATIVE AGENT
To: CASELLA WASTE SYSTEMS, INC.
Reel/Frame 045798/0993 →
PATENT SECURITY AGREEMENT Recorded Jun 15, 2017
From: CASELLA WASTE SYSTEMS, INC.
To: BANK OF AMERICA, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 042827/0065 →
SECURITY INTEREST Recorded Mar 3, 2015
From: CASELLA WASTE SYSTEMS, INC.
To: BANK OF AMERICA, N.A., AS AGENT
Reel/Frame 035078/0505 →
RELEASE OF SECURITY INTEREST Recorded Nov 8, 2012
From: WILMINGTON TRUST COMPANY, AS COLLATERAL AGENT
To: CASELLA WASTE SYSTEMS, INC.
Reel/Frame 029266/0824 →
2ND LIEN PATENT SECURITY AGREEMENT Recorded Jul 27, 2009
From: CASELLA WASTE SYSTEMS, INC., A DELAWARE CORPORATION
To: WILMINGTON TRUST COMPANY, AS COLLATERAL AGENT
Reel/Frame 023003/0383 →
SECURITY AGREEMENT Recorded Jul 15, 2009
From: CASELLA WASTE SYSTEMS, INC.
To: BANK OF AMERICA, N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 022951/0908 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 23, 2008
From: CASELLA, DOUGLAS R.
To: CASELLA WASTE SYSTEMS, INC.
Reel/Frame 021280/0208 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 12, 2007
From: CASELLA, DOUGLAS R.
To: CASELLA WASTE SYSTEMS, INC.
Reel/Frame 019957/0483 →