Granted Patent
B2
US 12,709,560 · 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)
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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.
Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST
Recorded Mar 12, 2025
From: TARPEH, WILLIAM A.; KOGLER, ANNA; CLARK, BRANDON D.; LIU, MATTHEW JUNJIE; CHOW, WILLIAM
To: THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIVERSITY
Reel/Frame 070491/0092 →
Continuity (2)
Provisional Application
63065988
· Aug 14, 2020
Related Publication
20240025776A1
· Jan 25, 2024
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