The process for treating an ammonium containing liquid by denitrification treatment of an ammonium containing liquid containing at least ammonium comprises carrying out nitrate reduction treatment of reducing nitrate contained in or added to the ammonium containing liquid to nitrite, and carrying out anaerobic ammonium oxidation treatment of simultaneously anaerobically denitrifying nitrite produced in the nitrate reduction treatment and ammonium contained in the ammonium containing liquid by anaerobic ammonium oxidizing bacteria.
This is a Division of Application No. 12/073,637 filed Mar. 7, 2008, which is a Divisional of Application No. 11/359,529 filed Feb. 23, 2006, now U.S. Pat. No. 7,537,698. The disclosure of the prior applications is hereby incorporated by reference herein in its entirety.
Priority Data
Feb 28, 2005 [JP] 2005-054423 Mar 04, 2005 [JP] 2005-061375 May 18, 2005 [JP] 2005-145785
