Efficient total nitrogen removal in an ammonia gas biofilter through high-rate OLAND.
Ammonia gas is conventionally treated in nitrifying biofilters; however, addition of organic carbon to perform post-denitrification  is required to obtain total nitrogen removal. Oxygen-limited autotrophic nitrification/denitrification (OLAND), applied in full-scale for wastewater treatment, can offer a cost-effective alternative for gas treatment. In this study, the OLAND application thus was broadened toward ammonia loaded gaseous streams. A down flow, oxygen-saturated biofilter (height of 1.5 m; diameter of 0.11 m) was fed with an ammonia gas stream (248 ± 10 ppmv) at a loading rate of 0.86 ± 0.04 kg N m(-3) biofilter d(-1) and an empty bed residence time of 14 s. After 45 days of operation a stable nitrogen removal rate of 0.67 ± 0.06 kg N m(-3) biofilter d(-1), an ammonia removal efficiency of 99%, a removal of 75-80% of the total nitrogen, and negligible NO/N(2)O productions were obtained at water flow rates of 1.3 ± 0.4 m(3) m(-2) biofilter section d(-1). Profile measurements revealed that 91% of the total nitrogen activity was taking place in the top 36% of the filter. This study demonstrated for the first time highly effective and sustainable autotrophic ammonia removal in a gas biofilter and therefore shows the appealing potential of the OLAND process to treat ammonia containing gaseous streams.
Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
Haydée
H
De Clippeleir
Emilie
E
Courtens
Mariela
M
Mosquera
Siegfried E
SE
Vlaeminck
Barth F
BF
Smets
Nico
N
Boon
Willy
W
Verstraete
D000641:Ammonia / Q000302:isolation & purification*; D001483:Base Sequence; D017931:DNA Primers; D005374:Filtration / Q000295:instrumentation*; D058465:Nitrification; D009584:Nitrogen / Q000302:isolation & purification*; D010100:Oxygen / Q000737:chemistry; D060888:Real-Time Polymerase Chain Reaction
D017931:DNA Primers; D000641:Ammonia; D009584:Nitrogen; D010100:Oxygen