Removal of Nitrate Nitrogen in Drinking Water with Hollow Fiber Bioreactor

我们使用polysulphone hollow fibers，polyvinyl alcohol which were hydrophilized with pore of 0.1μmas 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 polyvinylalcohol. The fiber module was furnished in The tubular reactor and The artificial ground watercontaining nitrate nitrogen was introduced to the outer surface of the fiber and hydrogen needed fornitrate was delivered from the hollow fiber's inner side. the hydrogen-oxidizingbacteria are autotrophic and need only an inorganic carbon and then the rate of multiplication ofthe microorganism and denitrification rate was maintained adequately at level of 6.0 mg/L ofinorganic carbon. The denitrification rate was also maintained high level at The range of pH6.5 toph9.5 .Subsequently we showed the influence of concentration of nitrate nitrogen in ground water onthe rate of denitrification at concentration of nitrate in artificialground water varied from 20mg /L to 400mg /L were measured and plotted。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]).它被应用于否认率(rate of denitrification ofautotrophic bacteria such as the hydrogen-oxidizing bacteria sufficiently high at lower level ofthe nitrate than the level in heterotrophic bacteria. the bacteria needed the some trace elementssuch as phosphorous，potassium and magnesium other than nitrate for denitrification High denitrification rate wereattained by the optimization of pH, the level of trace elementstemperature and pressure of hydrogen gas so on. The possibility of application of hollow fiberbioreactor for removal of nitrates in the ground water was shown。

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.