Microbial Charateristics Of Anaerobic Ammonium Oxidation At High Salinity And Normal Temperature

Anammox process possess three superior characteristics with low sludge yield, low energy consumption and no additional carbon source, which is a promising water treatment technique with high environmental application value. While the wastewater of treatment often contains saltions, higher salinity will increase osmotic pressure and kill microbes or lead microbial cells to dehydration so as to the separation wall and cytoplasm sleep. Biochemical reaction temperature mainly affects enzyme activity. Numerous studies have concentrated on the salinity of the anaerobic ammonia oxidation reactor performance, anaerobic ammonium oxidation activity, nitrogen removal efficiency, etc., these studies have confirmed the idea that the domesticated AnAOB can adapt to high salinity environment. This paper studied a number of changes after enhancing the salinity of anaerobic ammonia oxidation reactor, including denitrification performance and the relative content of An AOB, while different salinity anammox reactor, differences in microbial community structure of An AOB and associated bacteria were analyzed by high-throughput sequencing technology; in addition, research performance and community anaerobic ammonia oxidation reactor at room temperature microorganisms were studied. The main conclusions are as follows:(1) For studying on the effects of salinity on nitrogen removal performance of Anammox reactor, the influent salinity of the EGSB Anammox reactor R1 was increased from 18g/L to 28g/L by the gradient of 5 g/L. Results indicate that the An AOB experienced adaptation stage and stable stage during the increasing of salinity. The Anammox granular sludge was well adapted to salinity changes, because the adaptation stage was only about four days at each salinity upgrade.The result of the posture microscope shows that the colour of granular sludge in the reactor R1 was bright red, and the surface was uneven. there are many ridges and retraction, irregular in shape, with a long strip of the majority. SEM result indicates that granular sludge contained lots of cocci, bacillus and filamentous bacteria on the surface, There are a lot of holes existing inside the anaerobic ammonia oxidation sludge particles.Results of Fluorescence quantitative PCR showed that the salinity from 18g/L to 28g/L by the gradient of 5g/L, the relative content of An AOB in the reactor R1 upward trend, AnAOB under 28g/L salinity 16 S rRNA gene copy number was 3.7×108 copies/(mg-dry sludge, compared to other literature, An AOB at a higher abundance as usual in the reactor R1, so the reactor R1 remained a high nitrogen removal efficiency.(2) For studying on the effects of salinity on microbial community structure of Anammox reactor, the influent salinity of the EGSB Anammox reactor R1 was increased from 18g/L to 28g/L by the gradient of 5g/L. the diversity of microbial populations from high to low order as follow: 18g/L salinity sludge samples> 23g/L salinity sludge samples> 28g/L salinity sludge samples. The number of shared OUT under different salinity conditions accounts for 67.4% of the total number of OUT,the number of unique OUT is comparatively smaller. Under different salinity conditions, the differences of microbial species is small, but Contents of different kinds of microorganism are quite different from Heatmap.Anammox granule sludge samples under different salinities advantage Phylum are Planctomycetes, Proteobateria, Chloroflexi, their relative abundance accounting for about 88% levels to 94%, and their presence anaerobic previous studies ammonia oxidation reactor keep a consistent level of microbes these Phylum dominant.Samples genus with anammox activity is Brocadiaceae_unclassied and Candidatus_Kuenenia, the relative abundance of which under the salinity of 18g/L?23g/L?28g/L are 24.6%?56.7%?61.2, 17.7%?2.3% and 3.1% respectively. with the increase of salinity, it can be seen that the relative abundance of Brocadiaceae_unclassied bacteria gradually increased, and the relative abundance of bacteria Candidatus_Kuenenia dips at 23g/L salinity, during the salinity acclimation upgrade process, Brocadiaceae_ unclassied was more competitive than bacteria Candidatus_Kuenenia, the presence of AnAOB structure changed gradually from coexistence state of Brocadiaceae_ unclassied bacteria and bacteria Candidatus Kuenenia into Brocadiaceae_unclassied bacteria which takes advantage of the total bacteria. This indicates that there is competition between the AnAOB of the genus, and the high salinity is more conducive to the enrichment Brocadiaceae_unclassied bacteria.(3) nitrogen removal performance of anaerobic ammonium oxidation reactor R2 during the operation were analyzed, the results showed that at 33?, the first condition of a load lifting little impact on the nitrogen removal performance of the R 2 reactor, the reactor adaptation period was only 5d, When the reactor R2 is reduced from 33? to 19?, the denitrification performance of reactor R2 is not inhibited. At 19 ? conditions ammonia and nitrite nitrogen concentration increased from 100mg/L to 200mg/L respectively, ammonium?nitrite and total nitrogen removal rate decreased slightly, remained at 80%, 85 %and 80% about. In the present study, the temperature is about 19?, influent total nitrogen removal load up to 1.36kg·m-3·d-1, the reactor R2 was still of a good nitrogen removal performance.Planctomycetes, Proteobateria, Chloroflexi is dominant bacteria Phylum, the relative abundance of them accounted for 82.44% of the level of microbial populations, it is Candidatus_Kuenenia in the reactor R2 features bacteria, which can be adapted to room temperature(19?) conditions, and maintain a high biological nitrogen removal activity at this temperature.