Characteristics Of Denitrifier And Study On Removal Of Nitrate By Immobilized Cells

The content of the thesis was divided in two fields :l)Study on characterizations of Strain HPl and growth in chemostat. 2)Removal of nitrate in groundwater by immobilized denitrifier. Strain HPl , H-Su-1 , NO3-1 was isolated from sediment and was identified as Pseudomonas alcaligenes, Paracoccus denitrificans , Vibrio spp respectively.Through orthogonal test, the result showed that in Giltay culture effect of various factors on denitrification, on strain HPl: Cu2+>temperature> carbon source>C/N ratio> pH, on strain H-Su-1: C/N ratio> temperature> carbon source> Cu2+. It showed that the result was different on different denitrifiers. It had different result when a different factor influenced the denitrifiers. For this purpose , some factors were tested. Sorts of carbon source had little effect on nitrate reductase , but had effect on nitrous oxide reductases. pH had obvious effect on denitrification, and observations indicated that the optimum pH value was neutral and alkaline. Copper ion addition and its concentration in medium greatly influenced denitrification. In a concentration of 5mg/L, the nitrite reductases activity was increased ,but 200mg/L, the nitrite reductases activity was inhibited. It was proposed that the nitrite reductases of strain HP1 was the copper enzyme. Strain HPl could endure high concentration of nitrite, and it could grow in a nitrite concentration of 36mM. The activation energy for denitrification is lower, and the ratio between CO2 and N2O evolution is higher with temperature.The method of continuous culture was the base when microbiology in water area was studied. When carbon source or nitrate was limiting the kinetics of strain HPl in chemostat was studied. When nitrate was limiting, the equation was =0.197>