US 9,809,474 B2
Process for treating effluents containing nitrogen in ammonium form, and equipment for implementing this process
Laure Graveleau, Fresnes (FR)
Assigned to SUEZ INTERNATIONAL, (FR)
Appl. No. 14/761,639
Filed by DEGREMONT, Paris la Defense (FR)
PCT Filed Jan. 16, 2014, PCT No. PCT/IB2014/058331
§ 371(c)(1), (2) Date Jul. 17, 2015,
PCT Pub. No. WO2014/111878, PCT Pub. Date Jul. 24, 2014.
Claims priority of application No. 13 50447 (FR), filed on Jan. 18, 2013.
Prior Publication US 2015/0360981 A1, Dec. 17, 2015
Int. Cl. C02F 3/00 (2006.01); C02F 3/30 (2006.01); C02F 3/02 (2006.01); C02F 3/26 (2006.01); C02F 3/12 (2006.01); C02F 101/16 (2006.01)
CPC C02F 3/02 (2013.01) [C02F 3/006 (2013.01); C02F 3/12 (2013.01); C02F 3/1263 (2013.01); C02F 3/26 (2013.01); C02F 3/30 (2013.01); C02F 3/301 (2013.01); C02F 3/302 (2013.01); C02F 3/307 (2013.01); C02F 2101/16 (2013.01); C02F 2209/14 (2013.01); C02F 2209/15 (2013.01); C02F 2209/40 (2013.01); C02F 2209/42 (2013.01); C02F 2209/44 (2013.01); Y02W 10/15 (2015.05)] 9 Claims
OG exemplary drawing
 
1. A process for treating effluents containing nitrogen in ammonium form, employing a sequential bioreactor, wherein said process comprises:
introducing into the bioreactor in one or more successive volume fractions a volume of effluents to be treated in a complete cycle,
treating each volume fraction during a subcycle, the subcycle comprising:
supplying in a supply phase one of the volume fractions to the bioreactor,
determining, at an end of the supply phase, an initial concentration of N—NH4 in the bioreactor,
setting a desired concentration of N—NH4 in the bioreactor to be reached by an end of an aerating step,
determining the weight of N—NH4 to be treated from the volume of effluents in the bioreactor by the end of the supply phase, and from the difference between the initial concentration of N—NH4 in the bioreactor and the desired concentration of N—NH4 in the bioreactor to be reached by the end of the aerating step,
setting a maximum aeration time TM for the aerating step,
determining an initial air flow rate Qairinit, for a start of the aerating step, the initial air flow rate being determined taking into account the weight of N—NH4 to be treated and the maximum aeration time TM, from the following formula:
Qairinit=k×weight of N—NH4 to be treated×60/TM
where:
Qairinit=initial air flow rate to be applied, in Nm3/h (normal m3 per hour),
k=coefficient between 0.1 and 0.5,
weight of N—NH4 to be treated, expressed in grams,
TM expressed in minutes, and
in the case of injection of oxygen, the oxygen flow rate is deduced from Qairinit and the oxygen content of the air, and
injecting air or oxygen into the effluents in the bioreactor during the aerating step starting with the determined initial air flow rate so that at least partial oxidation of the ammonium to nitrates is achieved during the aerating step, and
decanting and emptying the bioreactor after an end of the complete cycle.