Nitrogen removal from wastewaters at low C/N ratios with ammonium and acetate as electron donors

A denitrifying upflow anaerobic sludge blanket (UASB) reactor was operated at different nitrate loading rates at a C/N ratio of 1.2, with acetate as an electron donor. This resulted in an increase in the accumulation of nitrite. After this, the UASB reactor was supplemented with 100 mg NH 4 + –N l −...

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Bibliographic Details
Published in:Bioresource technology 2001-09, Vol.79 (2), p.165-170
Main Authors: Cervantes, Francisco J., De la Rosa, David A., Gómez, Jorge
Format: Article
Language:English
Subjects:
Acetates - metabolism
Anaerobic ammonium oxidation
Anaerobiosis
Autotrophic denitrification
Biological and medical sciences
Biological treatment of waters
Bioreactors
Biotechnology
Carbon - metabolism
Environment and pollution
Fundamental and applied biological sciences. Psychology
Hot Temperature
Industrial applications and implications. Economical aspects
Nitrates - analysis
Nitrite reduction
Nitrites - analysis
Nitrogen - metabolism
Nitrogen removal
Oxidation-Reduction
Quaternary Ammonium Compounds - metabolism
Time Factors
Waste Disposal, Fluid - methods
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Summary:A denitrifying upflow anaerobic sludge blanket (UASB) reactor was operated at different nitrate loading rates at a C/N ratio of 1.2, with acetate as an electron donor. This resulted in an increase in the accumulation of nitrite. After this, the UASB reactor was supplemented with 100 mg NH 4 + –N l −1 d −1 , while acetate was gradually limited in the medium. This prevented nitrite accumulation at a C/N ratio of 0.6 due to an enhanced nitrite reduction rate achieved in the reactor. An increasing amount of ammonium was consumed when the C/N ratio was lowered in the medium. This suggested that ammonium was used as an alternative electron donor during denitrification, which is supported by nitrogen balances. Nitrite was shown to be toxic for the nitrogen removal process at 200–400 mg NO 2 − –N l −1 when the C/N ratio was decreased to 0.4 leading to formation of ammonium. The present study showed that addition of ammonium as an alternative electron donor for denitrification achieved a nitrogen removal process with negligible accumulation of undesirable intermediates.
ISSN:0960-8524
1873-2976
DOI:10.1016/S0960-8524(01)00046-3