公开(公告)号：US20180208491A1

公开(公告)日：2018-07-26

申请号：US15478456

申请日：2017-04-04

Applicant: Hitachi, Ltd.

Inventor： Yuya KIMURA ,  Shinichi YOSHIKAWA ,  Shoko MIYAMAE ,  Hajime IKUTA

IPC: C02F3/30 ,  C02F3/00

CPC classification number: C02F3/303 ,  C02F3/006 ,  C02F3/307 ,  C02F2101/16 ,  C02F2103/20 ,  C02F2103/343 ,  C02F2103/346

Abstract: Provided is a method for treating ammoniacal nitrogen in wastewater performed via biologically oxidizing ammoniacal nitrogen, and producing nitrite nitrogen and nitrate nitrogen at a desired rate. In the method, ammoniacal nitrogen is oxidized by bacterial sludges to produce at least either of nitrite nitrogen and nitrate nitrogen. Specifically, the method includes an inactivating treatment step of treating the bacterial sludges with an inactivating operation via sterilizing bacteria or causing bacteriostasis, and a nitrifying treatment step of oxidizing the ammoniacal nitrogen by the bacterial sludges thus treated in the inactivating operation. Production amounts of the nitrite nitrogen and the nitrate nitrogen are controlled by adjusting biomass of the bacterial sludges to be treated in the inactivating operation, and/or a time interval between the inactivating operations each repeatedly performed in combination with the nitrifying treatment step.