| As the development of industry and agriculture and the improvement of people’s living standard, environmental pollution problems has become increasingly serious problem, and hindered the sustainable development of society. Water pollution has increasingly become great concern of people. Water pollution includes nitrogen and phosphorus pollution, etc. Nitrogen pollution is mainly caused by long-term emissions of nitrogen compounds in water, which will lead to water quality deterioration ultimately, and destroy the ecological balance of the water. Traditional biological denitrification theory suggests that the wastewater denitrification is mainly completed by a group of autotrophic, aerobic nitrifying bacteria and a group of heterotrophic,anaerobic denitrifying bacteria. But the rate of nitrification is slowly, organic matter of high concentration is highly sensitive load, and Large reactor. In recent years, new denitrification bacteria and technology discovered, which overcame the shortcomings of the traditional nitrogen removal process, and being a hot po int of biological denitrification.Six simultaneous nitrification and denitrificatio n bacteria strains were isolated from the Huandihe River, which is a seriously contaminated river located at Jiaozhuang, Baoding. After enrichment cultured, 22 strains were separated by ammonia sulfate as the sole nitrogen in the medium. 15 strains of heterotrophic nitrification had through of griess reagent and Nessler’s assay determined, and 6 strains are better than others, so called YX3,YX4,YX6,YX7,YX8 and YX10. By morphological, physiological, biochemical identification and phylogenetic analysis based on 16 S r DNA sequence, these strains were identified as Pseudomonas spp. After cultivated in liquid heterotrophic ammoniation medium at 30°C by shaking at 150 r/min for 72 h, the ammonia nitrogen(N H4+-N) removal rates of six strains were more than 91%. After cultivated in liquid denitrification medium at 30°C by shaking at 150 r/min for 72 h, the nitrate nitrogen(NO3--N) removal rates of six strains reached more than 80%. These results showed that all these strains were capable of simultaneous nitrification and denitrification.6 strains bacteria can make better use of ammonia, nitrite, nitrate nitrogen for growth and reproduction. when ammonia sulfate as sole nitrogen source, after shaking for 72 h at 30℃, 150 r / min, and concentration of NH4+-N was77.8±6.26 mg/L in medium, the NH4+-N removal rates of the six strains were more than 88%, with the NH4+-N removal, NO2--N and NO3--N only accumulated in very low concentration, and then decreased. when sodium nitrate as sole nitrogen source, after shaking for 72 h at 30℃, 150 r / min, and concentration of nitrite nitrogen(NO2--N) was 94.3±8.25 mg/L in medium, the NO2--N removal rates of the six strains were more than 80%, with the NO2--N removal, NO3--N only accumulated in very low concentration. when sodium nitrate as sole nitrogen source, after shaking for 72 h at 30℃, 150 r / min, and concentration of NO3--N was 101.96±9.59 mg/L in medium, the NO3--N removal rates of the six strains were more than 87%, with the NO3--N removal, and NO2--N only accumulated in very low concentration. These results showed that bacteria could use ammonia best, followed by nitrate and nitrite.Studies showed that when 6 strains YX3, YX4, YX6, YX7, YX8 and YX10 were faced to the high ammonia pharmaceutical wastewater with 30000 ppm Na C l in steroid production enterprises, all the strains could tolerance high ammonia pharmaceutical wastewater and remove NH4+-N from it, when concentration of NH4+-N was 512.36±78.47mg/L, concentration of CODCr was 3983.31± 906.32 mg/L in pharmaceutical wastewater, N H4+-N removal rates of strains YX3, YX4,YX6, YX7,YX8 and YX10 were about more than 53.52±15.82%, CODCr removal rates were more than 65.15±9.79% after cultured for 3d. After four months of acclimation, the NH4+-N and CODCr remove rates of six strains were all improved under the same culture conditions. Among them, the remove rates of ammonia nitrogen and CODCr of strain YX3 improved significantly, NH4+-N remove rates was improved 11.68%,CODCr remove rates was improved 11.52%. This suggests that all the six strains have great application potential in high ammonia nitrogen pharmaceutical wastewater treatment. |
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