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| The start-up and characterization of a three-stage nitrification biological contact oxidation reactor |
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Abstract The start-up and characterization of a three-stage nitrification biological contact oxidation reactor were studied using actual sewage. The experimental results showed that by using the intermediate sedimentation tank effluent as influent for the biofilm incubation in biological contact oxidation reactor, the biofilm matured within 20 day without additional inoculation sludge, and the NH4+-N removal efficiency reached above 98%. The biomass and biofilm thickness of three stages gradually decreased in the flow direction, and the highest biomass and biofilm thickness were 1271.25mg/L and 119.45 μm respectively. By analyzing the nitrifying characteristics, the results revealed that the three stages had higher specific nitrification uptake rate (SNUR) even at low temperature of 15℃, and the second and third stages were both higher than the first stage at the same temperature (15, 23, 32℃). In view of the above phenomenon, the ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) ratio in each stage were roughly estimated according to the specific oxygen uptake rate (SOUR). The AOB of three stages were (25.64+4.89)%, (34.59+5.02)% and (42.50+1.57)% while the NOB were (23.52+3.35)%, (39.65+4.26)%, (40.69+2.19)% respectively. In addition, the fluorescence in situ hybridization (FISH) results derived on day 125after initial operation showed that the bacterial distribution of three stages do exist differences.The AOB and NOB were more dominant in the second and third stages, compared to the first stage.
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Received: 09 April 2014
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