IP Library › Granted Patent US 12709560
Granted Patent B2
US 12709560 · App. 18/041,678 · Granted Aug 18, 2026

Systems and methods of flexible electrochemical stripping to recover alkaline ammonia and acidic ammonium from wastewaters

Inventors: William A. Tarpeh (Union City, CA); Anna Kogler (Stanford, CA); Brandon D. Clark (Attleboro, MA); Matthew Junjie Liu (Palo Alto, CA); William Chow (Sherman Oaks, CA)
Assignee: The Board of Trustees of the Leland Stanford Junior University
C02F1/4693C02F1/20C02F1/46109C02F2001/46142C02F2101/16C02F2103/005C02F2201/46115
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Quick Facts
Patent No.
US 12709560
App. No.
18/041,678
Granted
Aug 18, 2026
Kind
B2
Abstract

Most nitrogen recovery techniques recover acidic ammonium fertilizers, and few enable alkaline ammonia recovery. Many embodiments provide multi-chamber electrochemical stripping reactors to recover alkaline ammonia and acidic ammonium from wastewater. The reactor combines electrodialysis and membrane stripping. The acidic and alkaline product portfolio for wastewater-derived ammonia expand implementation opportunities for nitrogen recovery.

Claims (27)

1 . An electrochemical stripping reactor for removing ammonia and ammonium and recovering acidic ammonium and alkaline ammonia comprising:

at least two anode chambers and each chamber comprising at least one anode;

at least two cathode chambers and each chamber comprising at least one cathode;

at least one cation exchange membrane; and

at least one gas permeable membrane;

wherein the anode chambers and the cathode chambers are disposed in alternating arrangement, and the cation exchange membrane and the gas permeable membrane are disposed in alternating arrangement; wherein the cation exchange membrane is disposed between a first anode chamber and a first cathode chamber sequentially, and the gas permeable membrane is disposed between the first cathode chamber and a second anode chamber sequentially;

wherein at least the second anode chamber recovers acidic ammonium; and

wherein at least a second cathode chamber recovers alkaline ammonia.

2 . The electrochemical stripping reactor of claim 1 , wherein the anode chambers have a lower pH value than the cathode chambers.

3 . The electrochemical stripping reactor of claim 1 , wherein the anode chambers have a pH value lower than 7 and the cathode chambers have a pH value higher than 7.

4 . The electrochemical stripping reactor of claim 1 , wherein an ammonia-containing aqueous stream influent is added to the first anode chamber or the first cathode chamber.

5 . The electrochemical stripping reactor of claim 4 , wherein the ammonia-containing aqueous stream influent is urine, municipal wastewater effluent, or fecal sludge treatment plant effluent.

6 . The electrochemical stripping reactor of claim 1 , wherein the reactor operates in a concurrent mode or a staggered mode.

7 . The electrochemical stripping reactor of claim 1 , wherein an ammonium removal efficiency is up to 100%.

8 . The electrochemical stripping reactor of claim 1 , wherein a total ammonium recovery efficiency is at least 90%.

9 . The electrochemical stripping reactor of claim 1 , wherein a distribution of a total ammonium recovery has controlled alkaline ammonia and acidic ammonium production.

10 . The electrochemical stripping reactor of claim 1 , wherein a total alkaline ammonium recovery efficiency is at least 65%.

11 . The electrochemical stripping reactor of claim 1 , wherein a total acidic ammonium recovery efficiency is at least 25%.

12 . The electrochemical stripping reactor of claim 1 , wherein the acidic ammonium is an ammonium salt.

13 . The electrochemical stripping reactor of claim 12 , wherein the ammonium salt is ammonium sulfate.

14 . The electrochemical stripping reactor of claim 1 , wherein the alkaline ammonia is ammonium hydroxide or aqueous ammonia.

15 . The electrochemical stripping reactor of claim 1 , wherein the anode comprises a conductive material that catalyzes oxygen evolution, wherein the cathode comprises a conductive material that catalyzes hydrogen evolution.

16 . The electrochemical stripping reactor of claim 15 , wherein the anode comprises a titanium mesh coated with iridium-tantalum mixed metal oxide.

17 . The electrochemical stripping reactor of claim 15 , wherein the cathode comprises a stainless steel mesh.

18 . The electrochemical stripping reactor of claim 1 , wherein the cation exchange membrane comprises gel polystyrene cross linked with divinylbenzene and modified with sulphonic acid functional group.

19 . The electrochemical stripping reactor of claim 1 , wherein the gas permeable membrane comprises a hydrophobic material allowing passage of gaseous species and resistant to wetting by water.

20 . The electrochemical stripping reactor of claim 19 , wherein the gas permeable membrane comprises PTFE or polyethylene.