Research On Separation, Identification And Application Of Ammonifying Bacteria From Biological Aerated Filter Reactor

Owing to biological aerated filter (BAF) reactor had better nitrogen removal efficiency, this paper studied on separation, identification and application of ammonifying bacteria from BAF reactor. Firstly,9ammonifying bacterium were initially screened from the biofilm of the BAF reactor. Then we elected the strain T03and T05which could effectively decompose organic nitrogen from the9strains for further studies on the ammoniation characteristics. What’s more, through morphologic observation and physiological-biochemistry characteristic analysis, strains T03, T05were preliminarily identified as Alcaligenes and Micrococcus respectively which refered to "Identification Manual of Common Bacterial Systems". In addition, the research of T03, T05for ammoniation characteristics indicated that the strains were aerobic, the best nitrogen source was protein, the suitable temperature was30℃, the suitable pH value was7.0and the best inoculum quantity was5%. In these operating parameters, organic nitrogen in the culture could be effectively decomposed by the strains and organic nitrogen decomposition rate was up to86.91%and69.98%respectively.When microorganisms were in different nutritional conditions and environmental conditions, the mycelium growth speed was different. The fermentation composition and fermentation conditions of the strains T03and T05would be optimized by designing orthogonal tests. The results showed that strain T03fermentation concentration was10.37g/L for24h, at30℃, in7.0pH value and5%inoculums. And ingredient of the medium included3.0g glucose,5.0g Peptone,3.0g beef extract,0.3g K2HPO4,0.25g NaCl and0.01g FeSO4in1000mL distilled water. And that strain T05fermentation concentration was8.47g/L for30h, at35℃, in7.0pH value and5%inoculums. And the ingredient of the medium included3.0g glucose,5g Peptone,3.0g beef extract,0.5g K2HPO4,0.75g NaCl, and0.01g FeSO4in 1000mL distilled water.Polymerase chain reaction (PCR) products were obtained by the PCR sequencing and matching with Marker. The electrophoresis was a single clear belt and was good of specificity without apparent non-specific amplification products. The size of16S rDNA fragments was1426bp by sequencing. This DNA sequence was deposited to GeneBank under accession number JF698681. Similar16S rRNA gene sequences which retrieved from GeneBank were aligned, refined and used to generate a phylogentic tree. Based on phylogenetic analysis of the16S rDNA partial gene sequence, the strain was considered of belonging to the Alcaligenes faecalis subsp. Parafaecalis G and homology was as high as99.6%. The strain T03was eventually identifited as Alcaligenesfaecalis.In order to solve the problem of low ammonia nitrogen removal efficiency in the traditional Constructed Wetland of Plant Floating Island, two engineering bacteria strains T03and T05with a high ammonifying ablity was isolated from the laboratory to strengthen organic nitrogen decomposition in the system. The results showed that at48h, the organic nitrogen decomposition rate increased by11.16%and8.86%respectively by adding the strain agent T03and T05; the organic nitrogen concentration were4.40mg/L and5.14mg/L respectively, which reduced by3.83mg/L and1.98mg/L compared with in the control group. At72h, the effluent ammonia nitrogen were6.74mg/L and7.43mg/L respectively by adding the strain agent T03and T05while at72h it had not been degraded and at144h it was9.86mg/L in the control group. It was significant to strengthen organic nitrogen’s decomposition and ammonia nitrogen removal efficiency by adding ammonifying bacteria agent.The separation and identification of ammonifying bacteria from biological aerated filter reactor and ammonification performance were systematically researched which was of great significance to provide a certain valuable reference for further studies on ammoniation organic nitrogen and the ammoniation characteristics of BAF reactor.