Nitrogen removal in intermittently aerated biofilm airlift reactor

Journal Article · Sun Mar 01 00:00:00 EST 1998 · Journal of Environmental Engineering

DOI:https://doi.org/10.1061/(ASCE)0733-9372(1998)124:3(239)· OSTI ID:577375

Benthum, W A.J. van; Mathijssen, J P.M.; Sunde, J; Loosdrecht, M C.M. van; Heijnen, J J ^[1]; Garrido, J M ^[2]

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1. Delft Univ. of Technology (Netherlands). Kluyver Lab. for Biotechnology
2. Univ. of Santiago de Compostela (Spain). Dept. of Chemical Engineering

Nitrogen compounds like ammonium, nitrite, and nitrate can be found in domestic as well as industrial wastewaters. These compounds can cause many environmental problems in surface waters but can be removed by applying nitrification and denitrification processes. Denitrification was integrated in a nitrifying biofilm airlift suspension reactor by intermittent aeration. A total nitrogen-removal efficiency of 75% was reached at an aerobic ammonia load of 5 kg{sub N}{center_dot}m{sup {minus}3}{center_dot}d{sup {minus}1}. Acetate was added to the reactor during the anoxic periods. The system was operated at sufficiently long anoxic hydraulic retention times to allow suspended growth of denitrifying heterotrophs. However, the heterotrophic biomass did not grow in suspension but grew as protuberances and layers on the nitrifying biofilms. Nitrification and denitrification occurred via nitrite as an intermediate, possibly because denitrifiers outcompeted the nitrite oxidizers. Because of the establishing of the nitrite route, a low average COD/N ratio of 2.6 kg{sub COD}{center_dot}kg{sub N}{sup {minus}1} was obtained. When denitrifying operation with acetate addition was started, initially almost all nitrogen removed was emitted as nitrous oxide. Subsequently, the nitrous oxide emission strongly decreased to almost zero in a period of 30 days, while the nitrogen-removal efficiency was maintained.

• Sponsoring Organization: USDOE
• OSTI ID: 577375
• Journal Information: Journal of Environmental Engineering, Vol. 124, Issue 3; Other Information: PBD: Mar 1998
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
BIOREACTORS
NITRATES
BIODEGRADATION
WASTE WATER
PERFORMANCE TESTING
BENCH-SCALE EXPERIMENTS
WATER POLLUTION
REMEDIAL ACTION