Organics and nutrient recovery from anaerobic digester residues

Patent metadata

Field	Value
Publication number	US-2016318819-A1
Application number	US-201615209293-A
Country	US
Kind code	A1
Filing date	Jul 13, 2016
Priority date	Feb 17, 2011
Publication date	Nov 3, 2016
Grant date	—

Abstract

Sludge from an anaerobic digester is treated to recover one or more of fibers, or solids or liquids with a high nutrient content. The solids or liquids can be used as a fertilizer. The fibers can be used in a plant growing medium. Solids are separated from liquids in the sludge and dried. The solids may be dried to produce a flake or pellet. Ammonia in the liquids is recovered and used to produce a concentrated acidic ammonium salt solution. This solution may be mixed with the solids to produce a nitrogen enhanced solid. The fibers and solids or liquids can also be used in combination to produce an enhanced plant growing medium. A device and process for removing ammonia from a liquid can be used in the system or separately.

First claim

We claim:

1 . An apparatus for treating sludge comprising,
(a) one or more of a mechanical dewatering device and a dryer configured to receive the sludge and to output a solids fraction and a liquid fraction; (b) an ammonia recovery system to receive the liquid fraction and output an acidic ammonium salt solution; (c) a pellet making machine to receive the solids fraction and the acidic ammonium salt solution and to combine them into pellets.

2 . The apparatus of claim 1 further comprising an air flow drier to receive and dry the pellets.

3 . The apparatus of claim 1 wherein the ammonia recovery system comprises one or more of a steam based ammonia stripper and ii) a vacuum induced ammonia gas extractor.

4 . The apparatus of claim 3 wherein the ammonia recovery system further comprises an ammonium salt solution concentrator.

5 . The apparatus of claim 1 further comprising an anaerobic digester to produce the sludge.

6 . A process of making a fertilizer pellet comprising combining dried solids extracted from anaerobic digester sludge with an acidified liquid comprising ammonia previously removed from the anaerobic digester sludge.

7 . The process of claim 6 further comprising drying the pellet by way of a flow of air at 90 degrees Celsius or less.

8 . A process comprising steps of a) recovering fibers and a filtrate from an anaerobic digester sludge; b) recovering solids and a liquid from the filtrate; and, c) recovering ammonia from the liquid.

9 . The process of claim 8 wherein the fibers are used in a plant growing medium.

10 . The process of claim 9 wherein at least some of the solid or liquids are added to the plant growing medium.

11 . The process of claim 8 wherein at least some of the solids or liquids are converted into a granule or flake form.

Assignees

• Anaergia Inc

Inventors

• Josse Juan Carlos
• Benedek Andrew
• Theodoulou Michael David
• Scott Zachary

Classifications

• C05G5/12

  Granules or flakes · CPC title

• C05F17/15

  the material being gas · CPC title

• C05C3/00 Primary

  Fertilisers containing other salts of ammonia or ammonia itself, e.g. gas liquor · CPC title

• C01C1/10

  Separation of ammonia from ammonia liquors, e.g. gas liquors {(as part of the ammonia synthesis process C01C1/04)} · CPC title

• C02F11/04

  Anaerobic treatment; Production of methane by such processes · CPC title