Diversity Of Microbial Community In Anammox Reactor And Effect Of Cd²⁺,Cr⁶⁺ On Its Performance

Because of the low carbon to nitrogen ratio and the large fluctuation of water quality,the traditional biological nitrogen removal technology has not been able to meet the needs of today.ANAMMOX as a new biological nitrogen removal process has attracted more and more attention,ANAMMOX process has no external carbon source,low power consumption and low sludge yield,it has become the main biological one used in the actual production of nitrogen removal potentially.Landfill leachate contains many metal ions,which may have some influence on the ANAMMOX process.In this study,the diversity of microbial communities in different ANAMMOX reactors was analyzed,and the effects of Cd²⁺ and Cr⁶⁺,which were higher in landfill leachate,on the removal of nitrogen from ANAMMOX process were investigated.In order to provide some theoretical guidance for the practical application of ANAMMOX.Conclusions are as follows:?1?The diversity of microbial communities in two different reactors was analyzed by high throughput sequencing.The relative abundance of microbial community and microbial community diversity in the same reactor were higher than those in the lower sludge.The relative abundance of microbial community and microbial community diversity in the ANAMMOX reactor with no packing were higher than that in the ANAMMOX reactor with simulated lunar soil packing.The relative abundance of the upper and lower sludge in the same reactor was significantly different.The purification and cultivation of ANAMMOX bacteria in the reactor with simulated lunar soil was higher,and the domestication was more successful.From the clustering of relative abundance?family?shows,In the same ANAMMOX reactor,the microbial colony population of the upper and lower sludge is quite different,and the microbial colony populations in different reactors are quite different too.?2?The short-term effect of cadmium ion on ANAMMOX process was evaluated using batch experiments.The results showed that a low impact on the nitrogen removal performance of ANAMMOX was found when Cd²⁺ concentration was less than 2 mg/L.However,when Cd²⁺ concentration was over 2 mg/L,increasing the concentration of Cd²⁺ would cause increased inhibition of nitrogen removal performance of ANAMMOX.The long-term effect of Cd²⁺ on denitrification performance of ANAMMOX reactor was studied by using continuous feeding water.Nearly 150-day long term experimental findings,it was found that when Cd²⁺ concentration was less than 5 mg/L,nitrogen removal performance of ANAMMOX would not be affected.When Cd²⁺ concentration reached or exceeded 10 mg/L,nitrogen removal performance of ANAMMOX would be affected.After about 25-day recovery cultivation,nitrogen removal performance of ANAMMOX could be restored.?3?The short-term effect of Cr⁶⁺ on ANAMMOX process was evaluated using batch experiments.The results showed that a low impact on the nitrogen removal performance of ANAMMOX was found when Cr⁶⁺ concentration was less than 0.1 mg/L.Increasing the concentration of Cr⁶⁺ would cause increased inhibition of nitrogen removal performance of ANAMMOX.The long-term effect of Cr⁶⁺ on denitrification performance of ANAMMOX reactor was studied by using continuous feeding water.Through 90-day continuous cultivation,when the Cr⁶⁺ concentration is higher than 0.1 mg/L and lower than 0.25 mg/L,The nitrogen removal performance of ANAMMOX reactor was inhibited slightly.When the Cr⁶⁺ concentration reaches 0.75 mg/L and above,the performance of ANAMMOX is significantly reduced,After about 25-day recovery cultivation,nitrogen removal performance of ANAMMOX can not restored,and the reactor collapsed.