Cocurrent biological nitrification and denitrification in wastewater treatment

Journal Article · Sun Nov 01 04:00:00 EST 1998 · Water Environment Research

DOI:https://doi.org/10.2175/106143098X123598· OSTI ID:318626

Spector, M

Repetitive conditioning of recycle activated sludge (RAS) under strict anaerobic conditions gradually changes the products of ammonia oxidation from nitrite and nitrate to nitrous oxide (N{sub 2}O) and nitrogen (N{sub 2}). Nitrite inhibits oxygen respiration of anaerobically conditioned sludge; biochemical oxygen demand (BOD) is then oxidized by nitrite, which is reduce to N{sub 2}O and N{sub 2}. When anaerobic RAS conditioning is initially imposed on a nitrifying system, Nitrobacter species continue to oxidize nitrite to nitrate and thus reduce the nitrite available to oxidize BOD. However, Nitrobacter in the mixed liquor gradually tend to wash out because the sole source of Nictrobacter energy, the oxidation of nitrite to nitrate, is diminished to the extent that nitrite is reduced. Incorporation of an RAS conditioning zone to the activate-sludge process results in evolution of a nonfilamentous biomass, which affects both cocurrent biological nitrification and denitrification (CBND) and biological phosphorus removal (BPR). The initial feed zone may be either aerobic or anaerobic. A final anoxic denitrification zone is desirable for removal of residual nitrite plus nitrate (NO{sub x}) from aeration effluent. Nitrous oxide, the main reaction product of CBND, promotes both global warming and destruction of the stratospheric ozone layer.

• Sponsoring Organization: USDOE
• OSTI ID: 318626
• Journal Information: Water Environment Research, Journal Name: Water Environment Research Journal Issue: 7 Vol. 70; ISSN 1061-4303; ISSN WAERED
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ACTIVATED SLUDGE PROCESS
BIODEGRADATION
DENITRIFICATION
INDUSTRIAL WASTES
NITRIFICATION
WASTE WATER