Full-scale nitrogen removal from digester liquid with partial nitritation and anammox in one SBR.
Full-scale application of partial nitritation and anammox in a single suspended-growth sequencing batch (SBR) reactor presented here confirm the process suitable for removing nitrogen from ammonium-rich wastewater with low concentrations of BOD and suspended solids: details of simple and robust process control based on online ammonium or conductivity signals are discussed by describing the full-scale startup at three municipal plants (five reactors in total). Ammonium oxidation rates of up to 500 gN m(-3) d(-1) with conversion to N2 of over 90% are achieved in a full-scale plant, but pilot results indicate that significantly higher rates are feasible. With continuous aeration at dissolved oxygen concentrations <1 mgO2 x L(-1), the nitrite oxidation and the anammox reaction occur simultaneously, allowing increased overall performance and simplified process control compared to separate aerobic end anaerobic phases (segregated either temporally or in different reactors). Sedimentation of the sludge requires special attention only during startup. Although the observed N2O emissions were slightly higher than in conventional nitrogen removal, the overall greenhouse gas emissions were lower, mainly due to energy-saving.
Joss
Adriano
A
Eawag, Swiss Federal Institute for Aquatic Science and Technology, Uberlandstrasse 133, PO Box 611, CH-Dübendorf, Switzerland. adriano.joss@eawag.ch
Salzgeber
David
D
Eugster
Jack
J
König
Roger
R
Rottermann
Karin
K
Burger
Sabine
S
Fabijan
Peter
P
Leumann
Susanne
S
Mohn
Joachim
J
Siegrist
Hansruedi
H
D019149:Bioreactors; D009573:Nitrites / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000379:methods
D009573:Nitrites; D000644:Quaternary Ammonium Compounds; D012722:Sewage; D014874:Water Pollutants, Chemical; D009584:Nitrogen; D010100:Oxygen