Systems and methods for recovering landfill gas

Patent metadata

Field	Value
Publication number	US-11633767-B2
Application number	US-202117229360-A
Country	US
Kind code	B2
Filing date	Apr 13, 2021
Priority date	Apr 13, 2021
Publication date	Apr 25, 2023
Grant date	Apr 25, 2023

Abstract

A landfill gas recovery system includes a waste layer disposed in a landfill and a capping layer overlying the waste layer. The capping layer includes a cured sealing layer and a loose fill layer between the waste layer and the cured sealing layer. The loose fill layer includes a granular fill material. The cured sealing layer includes a composite of the granular fill material and a cured water soluble polymer. The cured sealing layer is substantially impermeable to landfill gases formed within the waste layer.

First claim

The invention claimed is:

1. A landfill gas recovery system comprising:
a waste layer disposed in a landfill;
a capping layer overlying the waste layer, the capping layer comprising a cured sealing layer and a loose fill layer between the waste layer and the cured sealing layer; and
a landfill gas collection apparatus positioned at least partially under the cured sealing layer and in fluidic communication with a landfill gas wellhead outside the landfill,
wherein:
the loose fill layer comprises a granular fill material;
the cured sealing layer comprises a composite of the granular fill material and a cured water soluble polymer;
the cured sealing layer is substantially impermeable to landfill gases formed within the waste layer; and
the cured sealing layer has a thickness from 5 cm to 15 cm.

2. The landfill gas recovery system of claim 1 , wherein the composite comprises from 5% to 15% by weight cured water soluble polymer, based on the total weight of the cured sealing layer.

3. The landfill gas recovery system of claim 1 , wherein the landfill gas collection apparatus comprises a manifold that passes through at least the cured sealing layer and connects perforated recovery pipes under the cured sealing layer to the landfill gas wellhead.

4. The landfill gas recovery system of claim 1 , wherein the granular fill material comprises at least 50% by weight sand, based on the total weight of the granular fill material.

5. The landfill gas recovery system of claim 1 , wherein the cured water soluble polymer comprises a polyurethane.

6. The landfill gas recovery system of claim 1 , wherein:
the granular fill material comprises at least 50% by weight sand, based on the total weight of the granular fill material;
the cured sealing layer comprises from 5% to 15% by weight cured water soluble polymer, based on the total weight of the cured sealing layer; and
the cured water soluble polymer comprises a polyurethane.

7. The landfill gas recovery system of claim 1 , further comprising a plastic sheet between the cured sealing layer and the loose fill layer.

8. The landfill gas recovery system of claim 7 , wherein the plastic sheet comprises polyethylene or polyvinylchloride.

9. The landfill gas recovery system of claim 1 , wherein the landfill further comprises a second waste layer overlying the capping layer.

10. The landfill gas recovery system of claim 9 , wherein the landfill further comprises a second granular layer between the second waste layer and the capping layer.

11. The landfill gas recovery system of claim 1 , wherein the loose fill layer has a thickness from 20 cm to 40 cm.

12. A method for sealing a landfill for recovery of a landfill gas from the landfill, the method comprising:
applying an aqueous solution comprising a water soluble polymer onto a landfill cover overlying a waste layer of a landfill, the landfill cover comprising a loose fill layer comprising a granular fill material;
continuing to apply the aqueous solution until at least a portion of the granular fill material is saturated with the aqueous solution to a predetermined depth of the granular fill material; and
allowing the aqueous solution to cure to form a capping layer over the landfill, the capping layer comprising a cured sealing layer and an uncured portion of the loose fill layer between the waste layer and the cured sealing layer,
wherein:
the cured sealing layer comprises a composite of the granular fill material and a cured product of the water soluble polymer;
the cured sealing layer is substantially impermeable to landfill gases formed within the waste layer; and
the predetermined depth of the granular fill material is from 5 cm to 15 cm.

13. The method of claim 12 , wherein the aqueous solution comprises the water soluble polymer and water and the concentration of the water soluble polymer in the aqueous solution is from 3% to 9% by weight based on the weight of the aqueous solution.

14. The method of claim 12 , wherein the composite comprises from 5% to 15% by weight cured water soluble polymer, based on the total weight of the cured sealing layer.

15. The method of claim 12 , wherein the water soluble polymer comprises a polyurethane.

16. The method of claim 12 , wherein the granular material comprises at least 50% by weight sand, based on the total weight of the granular material.

17. The method of claim 12 , wherein the landfill cover further comprises a plastic sheet between a first portion of the loose fill layer and a second portion of the loose fill layer, whereby a position of the plastic sheet determines a depth of the loose fill layer to which the aqueous solution saturates the granular fill material.

18. The method of claim 17 , wherein the plastic sheet comprises polyethylene or polyvinylchloride.

19. The method of claim 12 , wherein applying the aqueous solution comprising the water soluble polymer onto the landfill cover overlying the waste layer of the landfill comprises spraying the aqueous solution onto the landfill cover.

20. The method of claim 19 , wherein the aqueous solution is sprayed onto the landfill cover at a rate from 5 L/m 2 to 15 L/m 2 .

Assignees

• Saudi Arabian Oil Co

Inventors

• Shana'A Jihad

Classifications

• B09B3/80 Primary

  involving an extraction step · CPC title

• B09B1/004 Primary

  Covering of dumping sites · CPC title

• Y02W30/30

  Landfill technologies aiming to mitigate methane emissions · CPC title