Method and apparatus for enhancing methane production

• US 5,695,641 A
• Filed: 02/14/1996
• Issued: 12/09/1997
• Est. Priority Date: 02/14/1996
• Status: Expired due to Fees

• Current Assignee: John P. Cosulich, William F. Cosulich
• Original Assignee: John P. Cosulich, William F. Cosulich
• Inventors: Cosulich, John P., Cosulich, William F.
• Primary Examiner(s): McCarthy, Neil
• Assistant Examiner(s): GREEN, THEODORE
• Application Number:
  US08/601,623
• Time in Patent Office: 664 Days
• Field of Search: 210/603, 210/610, 210/630, 210/631, 210/747, 48/198.1, 48/197 A, 405/129
• US Class Current: 405/128.5
• CPC Class Codes: B09B 1/00 Dumping solid waste
• CPC Class Codes: B09B 3/00 Destroying solid waste or transforming solid waste into something useful or harmless
• CPC Class Codes: C12M 21/04 for producing gas, e.g. biogas digesters for manure with production of biogas A01C3/028, biological treatment of water, waste water or sewage C02F3/00, C02F11/02, preparation of natural gas or syngas C10L3/06, C10L3/10
• CPC Class Codes: C12M 23/18 Open ponds; Greenhouse type or underground installations
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel
• CPC Class Codes: Y02W 30/30 Landfill technologies aiming to mitigate methane emissions

Abstract

A method and apparatus for increasing the anaerobic activity in a landfill in order to boost methane production by injecting ammonia to thereby reduce residual oxygen levels, provide a rich source of nitrogen nutrient for the anaerobic microbe population and increase the pH. The ammonia may be injected via dedicated injection wells or via extraction wells that are temporarily used as injection wells. The ammonia may be injected in any form, diluted by a non-oxidizing carrier gas or may alternatively be introduced in aqueous form.

Claims

1. A method for enhancing the rate of methane production within a landfill, comprising the steps of:

providing a system of leach pipes extending into said landfill; and

forcing ammonia into said landfill via said pipe system while limiting the presence of oxygen in said pipe system to less than 5% by volume to substantially reduce the oxygen content within said landfill whereby the rate of anaerobic biodegradation within said landfill is increased.

2. The method of claim 1, wherein said ammonia is dispersed within a carrier medium.

3. The method of claim 2, wherein said carrier medium is a gas and said ammonia is present at a concentration of about 2-10 percent.

4. The method of claim 3, wherein said carrier medium comprises landfill gas.

5. The method of claim 3, wherein said carrier medium comprises CO₂.

6. The method of claim 3, wherein said carrier medium comprises N₂.

7. The method of claim 2, wherein said carrier medium comprises leach water or landfill gas condensate collected from said landfill.

8. The method of claim 2, wherein said carrier medium comprises waste water from municipal or agricultural sources.

9. The method of claim 1 further comprising the step of utilizing the same system of leach pipes to extract methane.

10. The method of claim 9 further comprising the step of injecting a gas devoid of ammonia and having an oxygen content of less than 5% by volume for a predetermined period of time after forcing said ammonia into said landfill via said leach pipes and prior to extracting said methane therefrom.

11. The method of claim 1, wherein a second system of leach pipes is inserted into said landfill and methane is extracted from said landfill therethrough.

12. A method for facilitating anaerobic activity in an oxygen inhibited zone disposed within a landfill, said zone having an O₂ content of between about 0.2% and 2%, comprising the steps of:

providing a conduit extending into said oxygen inhibited zone; and

forcing ammonia into said conduit until said O₂ levels drops below about 0.2%.

13. The method of claim 12, wherein said ammonia is combined with a carrier gas.

14. The method of claim 13, wherein said ammonia is present at a concentration of about 2-10 percent.

15. The method of claim 12, wherein said ammonia is dissolved in leach water or water.

16. The method of claim 12, wherein said ammonia is dissolved in waste water from municipal or agricultural source.

17. The method of claim 12 further comprising the step of extracting methane.

18. The method of claim 17, wherein said methane extraction and said ammonia injection is performed sequentially.

19. The method of claim 17, wherein said methane extraction and said ammonia injection is performed simultaneously.