Method for biologically removing nitrogen from wastewater

Patent · Tue May 25 04:00:00 EDT 1993

OSTI ID:6350668

Kos, P

An activated sludge process for biologically removing BOD and nitrogen from wastewater is described comprising the steps of: (a) forming mixed liquor; (b) transferring the mixed liquor through a first nitrogen removal stage by directing the mixed liquor into and through first anoxic and aerobic treatment zones including maintaining the mixed liquor under anoxic conditions within the first treatment zone for a specified period to permit denitrifying organisms to reduce a portion of the nitrates and nitrites present in the mixed liquor to elemental nitrogen, transferring a portion of the mixed liquor from the first anoxic zone to the first aerobic zone and aerating the mixed liquor for a sufficient time period for nitrifying organisms to convert a portion of the ammonia and organic nitrogen in the mixed liquor into nitrates and nitrites, and circulating the mixed liquor back and forth between the first anoxic zone and the first aerobic zone of the first nitrogen removal stage to effectuate denitrification and nitrification; (c) transferring mixed liquor from the first nitrogen removal stage to a second nitrogen removal stage having a second anoxic zone and a second aerobic zone, and circulating the mixed liquor back and forth between the second anoxic zone and the second aerobic zone of the second stage to effectuate further denitrification and nitrification; (d) transferring the mixed liquor treated in the first and second nitrogen removal stages to a final clarifier where settled sludge is separated from purified supernatant; and (e) recycling at least a portion of the settled sludge to form the mixed liquor.

• Assignee: T. Krueger, Inc., Cary, NC (United States)
• Patent Number(s): US 5213681; A
• Application Number: PPN: US 7-756440
• OSTI ID: 6350668
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320305* -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Industrial Waste Management
ACTIVATED SLUDGE PROCESS
AERATION
AEROBIC DIGESTION
AMMONIA
BIOCHEMICAL OXYGEN DEMAND
CHEMICAL REACTIONS
DENITRIFICATION
DIGESTION
ELEMENTS
HYDRIDES
HYDROGEN COMPOUNDS
LIQUID WASTES
MANAGEMENT
NITROGEN
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PROCESSING
REMOVAL
WASTE MANAGEMENT
WASTE PROCESSING
WASTE WATER
WASTES
WATER
WATER TREATMENT