Removal of Nitrate Nitrogen in Drinking Water with Hollow Fiber Bioreactor

我们使用了聚乙烯醇中空纤维，其中聚乙烯醇与0.1μm的pore使其羟基化，作为氢氧化细菌的免疫支持者（Paracoccus denitrificans）。细菌在其表面的空心纤维中被非流动性化，通过聚乙烯醇的介质。该纤维模块是在管状反应堆中制造的，并在含有人造地面水的硝酸盐硝酸盐被引入到需要减少硝酸盐的外表面的纤维和氢中。氢氧化细菌是自变性的，只需要非有机碳，然后微生物和脱氧率的多重速率至少维持在6.0毫克/升的非有机碳水平。去除率也在pH值6.5至pH值9.5的范围内保持较高的水平，而且我们还展示了土壤水去除率中氮素浓缩的影响。人工地面水中硝酸盐的浓缩率从20毫克/升到400毫克/升已被测量和滴定。比率在r= 52.2 C ^<0.79>的范围内（r ：脱氮率[mg-N/m^2·h]， C ：在[mg/L]中的硝酸盐浓度。它似乎表明，自性细菌的降解率，而氢氧化物的降解率在异性细菌的降解率低于硝酸水平的水平，而细菌需要一些痕迹元素，如磷酸、钙和镁，而其他的降解率则低于硝酸的降解率。高降解率可通过pH值的最佳化、痕量元素、温度和压力的水平来观察，因此，在地面水域中应用空心纤维生物反应器以去除硝酸盐的可能性。

We used the polysulphone hollow fibers, which were hydrophilized by polyvinyl alcohol with pore of 0.1μm, as the supporter for the immobilization of hydrogen-oxidizing bacteria(Paracoccus denitrificans). The bacteria were immobilized on the surface of the hollow fiber through the medium of polyvinyl alcohol. The fiber module was furnished in the tubular reactor and the artificial ground water containing nitrate nitrogen was introduced to the outer surface of the fiber and hydrogen needed for reduction of nitrate was delivered from the hollow fiber's inner side. The hydrogen-oxidizing bacteria are autotrophic and need only an inorganic carbon and then the rate of multiplication of the microorganism and denitrification rate was maintained adequately at level of 6.0 mg/L of inorganic carbon. The denitrification rate was also maintained high level at the range of pH6.5 to pH9.5.Subsequently we showed the influence of concentration of nitrate nitrogen in ground water on the rate of denitrification. The rate of denitrification at concentration of nitrate in artificial ground water varied from 20 mg/L to 400 mg/L were measured and plotted. The rate was approximated by r=52.2C^<0.79> at the range of the concentration (r : rate of denitrification [mg-N/m^2・h], C : concentration of nitrate nitrogen in [mg/L]). It was appeared that the rate of denitrification of autotrophic bacteria such as the hydrogen-oxidizing bacteria was sufficiently high at lower level of the nitrate than the level in heterotrophic bacteria.The bacteria needed the some trace elements such as phosphorous, potassium and magnesium other than nitrate for denitrification. High denitrification rate were attained by the optimization of pH, the level of trace elements, temperature and pressure of hydrogen gas so on. The possibility of application of hollow fiber bioreactor for removal of nitrates in the ground water was shown.