Joon Ae Ahn

US Patent:

8586337, Nov 19, 2013

Filed:

Oct 6, 2008

Appl. No.:

12/681123

Inventors:

Kartik Chandran - New York NY, US
Ran Yu - Danbury CT, US
Joon Ho Ahn - New York NY, US

Assignee:

The Trustees of Columbia University in the City of New York - New York NY

International Classification:

C12P 1/04
C12M 1/00

US Classification:

435170, 4352831

Abstract:

Methods of controlling a nitrification reaction in a biological nitrogen removal reactor to favor partial nitrification of ammonia to nitrite instead of complete oxidation of ammonia to nitrate are disclosed. In some embodiments, the methods include the following: maintaining a pH in the reactor within a range that promotes growth of ammonia oxidizing bacteria; maintaining a concentration of dissolved oxygen in the reactor within a range that limits the ammonia oxidizing bacteria from completing nitrification; selecting an operational solids retention time within a range suitable for maintaining increasing concentrations of the ammonia oxidizing bacteria in the reactor while reducing concentrations of nitrite oxidizing bacteria in the reactor; and increasing a concentration of free ammonia in the reactor thereby inhibiting growth of the nitrite oxidizing bacteria in the reactor.

US Patent:

20140339157, Nov 20, 2014

Filed:

Nov 19, 2013

Appl. No.:

14/083549

Inventors:

Kartik Chandran - New York NY, US
Ran Yu - Danbury CT, US
Joon Ho Ahn - New York NY, US

International Classification:

C02F 3/00
C02F 3/02

US Classification:

210620, 210 961

Abstract:

Methods of controlling a nitrification reaction in a biological nitrogen removal reactor to favor partial nitrification of ammonia to nitrite instead of complete oxidation of ammonia to nitrate are disclosed. In some embodiments, the methods include the following: maintaining a pH in the reactor within a range that promotes growth of ammonia oxidizing bacteria; maintaining a concentration of dissolved oxygen in the reactor within a range that limits the ammonia oxidizing bacteria from completing nitrification; selecting an operational solids retention time within a range suitable for maintaining increasing concentrations of the ammonia oxidizing bacteria in the reactor while reducing concentrations of nitrite oxidizing bacteria in the reactor; and increasing a concentration of free ammonia in the reactor thereby inhibiting growth of the nitrite oxidizing bacteria in the reactor.