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The function of HCO3- in the partial nitrification and influence on nitrification efficiency |
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Abstract The main function of HCO3- in partial nitrification process was investigated by inoculating nitrification biofilm and to provide carbon source demand of nitritation stage in partial nitrification/anammox process to treat wastewater with high ammonia nitrogen and low carbon. The results show that the nitrification efficiency reached 0.99 kg/(m3·d) when the C/N ratio remained at 1.8 under the conditions of only decreasing influent concentration of HCO3- and unchanged ammonia concentration. However, the nitrification efficiency decreased to 0.67kg/(m3·d) at the same conditions, because the concentration of HCO3- was not enough to sustain pH environment in the nitrosation system, when C/N gradually reduced to 0.5. The pH value stabled at 8in nitrosation process, when the C/N ratio remained at 0.75. It had an obvious linear relationship between consumption of HCO3- and nitrification efficiency in nitrosation process. The tiny carbon in the air and wastwater meeted the demand of carbon source and the nitrification efficiency rate was up to 1.28kg/(m3·d) in nitrification process, when the pH value stabled at 8by using low concentration of alkali. The results indicated that neutralizing H+ produced by nitrification process and maintaining the pH environment needed for nitrosomonas were the main function of HCO3- in the partial nitrification process.
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Received: 07 July 2014
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