氢自养反硝化去除饮用水中硝酸盐的试验研究

Hydrogenotrophic Denitrification for the Removal of Nitrate in Drinking Water

研究了附着生长型序批式反应器内以氢气为电子供体的自养反硝化技术对饮用水中NO3^-的去除效果.采用透气膜作为氢气的扩散装置,增强氢气的传质效率,降低其爆炸的危险性.结果表明,氢自养反硝化技术能够有效地去除饮用水中的NO3^-,NO3^--N和TN的最高去除速率分别达6.45 mg/（L·h）和4.89 mg/（L·h）,NO2^--N有累积,最大累积量达11.58 mg/L.反应结束时,出水pH值为10.56,DOC增长了0.91 mg/L.建立了NO3^-和NO2^-还原反应的零级动力学模型,动力学常数分别为0.33-0.60 g/（g·d）和0.37-0.45 g/（g·d）.氢气压力大于40 kPa时,NO3^--N和TN的去除速率变化不大,分别为（5.97±0.08）mg/（L·h）和（4.25±0.04）mg/（L·h）;氢气压力为25 kPa时,NO3^-和TN的去除速率均显著降低.进水pH值为6抑制了反硝化反应,NO3^--N的去除速率仅为1.83 mg/（L·h）;pH值高于8利于反硝化进行,NO3^--N的去除速率为3.13 mg/（L·h）.

Autotrophic denitrification with hydrogen as the electron donor for the removal of nitrate in drinking water was investigated by using a bench-scale sequencing batch reactor in an attached growth system. Gas permeable membrane was employed as the hydrogen diffuser to improve the hydrogen mass transfer and decrease the explosion risk. The results showed that nitrate could be removed efficiently with this technology. The removal rates of NO3^- -N and TN could achieve 6.45 mg/（ L·h） and 4.89 mg/（ L·h） respectively, with the highest accumulation of NO2^- - N 11.58 mg/L. pH increased to 10.56 and DOC increased 0.91 mg/L. A zero order kinetic model was proposed for NO3^- and NO2^- reduction, with the kinetic coefficients in the ranges of 0.33 - 0.60 g/（ g· d） and 0.37 - 0.45 g/（ g· d） respectively, The removal rates of NO3^- -N and TN were not affected with the hydrogen pressure higher than 40 kPa, with the values （5.97± 0.08）mg/（L·h） and （4.25 ±0.04） mg/（L·h） respectively, while decreased remarkably when the hydrogen pressure was 25 kPa. The denitrification reaction was inhibited at pH 6 with the removal rate of NO3^- -N 1. 83 mg/（L·h） ; pH higher than 8 was the favorable condition for denitrification with the removal rate of NO3^- -N 3.13 mg/（L·h）.