Isolation And Nitrogen Removal Characteristics Of A Heterotrophic Nitrification-Aerobic Denitrification Strain

A bacterial strain named Pseudomonas stutzeri ZH-1,which exhibits theability of efficient heterotrophic nitrification and aerobic denitrification,was isolated fromthe sludge of Fenhe River?in Shanxi Province,China?and identified by 16 SrDNA sequencing as a strain of Pseudomonas stutzeriand the phylogenetic tree was established.The study of heterotrophic nitrification characteristics showed that the strain can conversion NH4⁺-N into gaseous and release directly.In order to research the ability of degrade NH4⁺-N for strains in different culture conditions,the results showed that the optimum conditions is sodium citrate as carbon source,pH 8.0,2% inoculated quantity,shaking speed was 100 rpm,NH4⁺-N density was 100.0 mg/L,and 30 degreecentigrade.And the ZH-1 make good nitrification with ammonium and the 24 h ammonium removal efficiency were 99.06% for 100.0 mg/LNH4⁺-N.Under aerobic conditions,when nitrate as the sole nitrogen source of culture medium,strains can showed good denitrification ability and no nitrite accumulation ultimately.And the strain ZH-1 removal rate for NO₃^--N can reach 100% and have no nitrite accumulation ultimately.In addition,we had researched the conditions of the ability of degrade NO₃^--N by strains ZH-1.The results indicated that sodium citrate as carbon source,pH 8.0,4% inoculated quantity,shaking speed was 100 rpm,and temperature 30°C were the optimum conditions.Under the condition of the initial N03--N concentration was 420.0mg/L,NO₃^--N can be degradation to 1.4 mg/L.and the removal rate can reach 99.67%.In this work,we had used the strain ZH-1 to process the actual sewage and made the fundamental experiment with it.Found in sewage without sterilization and don't add the little carbon source and small molecules of carbon source,ZH-1 under the condition of wastewater denitrification ability were 34.95% and 68.51% respectively,it also suggests that strains of actual wastewater denitrification effect is affected by the available carbon source;the denitrification ability of the the strain ZH-1 in actual wastewater can reached 34.95% and 64.36%,respectively.It also indicated that the strains of denitrification effect for actual wastewater was affected by the available carbon source;In no micromolecule carbon source added in the sterilization of sewage and added micromolecule carbon source condition,the denitrification ability for sewage were 14.73% and 65.5%,respectively.It also illustrates that the bacterias exists in wastewater being itself also has certain degradation ability for nitrogen.All of the test showed that the isolated strain ZH-1 showed strong ability of nitrification and denitrification at the same time.Also,in the future of wastewater treatment,ZH-1will be one of an candidate strain and has a broad application prospect in the future.