Start-up Of Nitritation And Deammonification In Autotrophic Biofilm In SBAF

Accumulation of ammonia in water environment has induced serious deterioration to the quality of water environment. Nitrogen from the wastewaters with low C/N ratio and high strength ammonia, such as digested sludge supernatant and landfill leachate, add up to over 50% total nitrogen form wastewater. Due to the fact that these wastewaters often are riddled by an extremely unfavourable C/N ratio, for the conventional biological nitrification-denitrification, C/N ratios below 4 increase the denitrification volume by a factor of 1.5 to 1.7, with a ratio below 2.5, sufficient denitrification cannot be achieved at all without the use of external carbon sources. Due to the fact that these wastewaters often are riddled by an extremely unfavourable C/N ratio, it is unfit to removal nitrogen from these wastewaters by biological nitrification-denitrification.Based on the latest research findings on biological nitrogen removal on low C/N ratio and high strength ammonia wastewater in both domestic and abroad, start-up and optimization of partial nitrification matched with ANAMMOX(Anaerobic Ammonium Oxidation) and deammonification was studied in SBAF (Submerged Biological Aerated Filter) which is widely used in the wastewater treatment. During the long-term operation of the bilfilm reactor, the factors which affect on the nitrification and deammonification were studied.The experiment results showed that 50% of the ammonium in the liquor was converted to nitrite with the temperature about 32±1℃; DO (dissolve oxygen) was 0.5~1.0 mg/L and pH was 7.4~7.7 in the nitrification reactor. But the temperature and the HRT had a little importance for the wash of nitrite oxidizers in autotrophic biofilm, and the biofilm thickness also had affection on the diffusional transport, so the operation parameter of the autotrophic biofilm reactors must be controlled strictly. 50% nitritation could not restored when the reactors was stopped after 20 days, and the nitrogen loss was so badly. Maybe the ANAMMOX reaction was happened in autotrophic biofilm reactors.A lab-scale deammonification biofilm was successful established in nitrifying biofilm in the submerged biofilm aerated filters system in four month. Experiment showed that the maximal ammonium transformation rate and total nitrogen removal rate could be reached 96.15% and 77.85 %, when pH was 7.8~8.0,DO was 1mg/L and temperature was 32℃. This was an important step forward in the application of...