PROCESS FOR BIOLOGICAL REMOVAL OF NITROGEN FROM WASTEWATER Russian patent published in 2018 - IPC C02F3/30 

FIELD: biotechnology.

SUBSTANCE: invention relates to a process for biological removal of nitrogen from wastewater. Method includes providing a stream of wastewater comprising ammonium, continuously supplying the stream of wastewater to a reactor containing granular sludge comprising granules having a core of anammox bacteria and an outer rim of ammonia oxidising bacteria, subjecting the wastewater in the reactor to ammonium oxidation under ammonium oxidising conditions comprising a temperature in the range of from 5 to 25°C, concentration of dissolved oxygen in the wastewater in the range of from 0.4 to 4.0 mg/l, and hydraulic retention time of the wastewater in the reactor in the range of 0.5 hours to 1.5 days, to obtain a gaseous stream comprising nitrogen and a dispersion of granular sludge and non-granular sludge in treated wastewater, continuously separating the dispersion obtained into a stream comprising granular sludge and a stream comprising treated wastewater and non-granular sludge and recycling the stream comprising granular sludge to the reactor and discharging the non-granular sludge from the process, when the granular sludge has a retention time in the reactor of at least ten times the hydraulic retention time,and wherein the retention time of any non-granular sludge in the reactor is equal to or at most three times the hydraulic retention time.

EFFECT: invention provides an efficient process for the combined nitrification and anaerobic oxidation of ammonium at low temperatures on an industrial scale for undiluted wastewater streams.

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