| The current research on electro-bio-coupling treatment technologies is mainly focused on the types of electro-bioreactors,the choice of plates,influencing factors,removal effects,and macro-biological effects and applications.However,there is a lack of research on microbial diversity in electro-bioreactors.Research on the micro-mechanism of microbial community structure has restricted the development and utilization of electro-biological coupling technology to a certain extent.Therefore,no matter from the development of the discipline itself,or from the perspective of theoretical and practical needs,it is urgent to further explore the relationship between external voltage and microorganisms,and explore the mechanism of the growth and metabolism of microorganisms and the effects of various conditions on this process.The mechanism provides a certain theoretical basis for the application of the electro-biological coupling reactor.Based on the analysis of the wastewater treatment effect in the electro-bio-coupled reactor,this study explores the microbial diversity in the electro-bio-coupled reactor using high-throughput sequencing technology,and systematically studies the effects of DC electric field on the microbial community diversity in the electro-bio-coupled reactor.Influence,and reveal the change law of microbial community diversity in the electrobioreactor in different pH ranges,and study the most suitable voltage of microorganisms in the electrobioreactor.In the experiment,two sets of the same plexiglass reactor were used,one set applied a certain current through the electrode plate,and the water output effect of the electric bioreactor under different external voltages was studied by an adjustable regulated power supply.Each time the voltage was adjusted,the reactor was stable.Around 3d,the stabilization time depends on the stability of the water quality data in the reactor.The other reactor was used as a blank control.Polyurethane packing is used as the filler in the reactor.In the electrobioreactor,a titanium electrode is used as the cathode,and a titanium-plated ruthenium electrode is used as the anode.The two groups of reactors use the water inlet method of bottom-in and top-out,and the bottom is uniformly aerated by a perforated plate.After constructing the electro-bio-coupling processing system,the membrane-hanging method was started by a composite membrane-hanging method,and a comparative study was performed with an ordinary bioreactor.The test results show that the changes in the CODcr and ammonia nitrogen removal rates of the two groups of reactors during the start-up phase of the membrane are basically the same.The removal rate of CODcr by the electrobioreactor is better than that of ordinary bioreactors.The removal of CODcr by the electrobioreactor after 33 days The rate is basically stable at about 89.29%,the removal rate of CODcr by ordinary bioreactors is stable at about 78.31%,and the removal rate of CODcr by electric bioreactors is 10.98% higher than that of ordinary bioreactors.The ammonia nitrogen removal effect of the two groups of reactors is not significantly different.After 33 days,the removal rate of ammonia nitrogen by the electric bioreactor can reach 77.64%,and the removal rate of ammonia nitrogen by ordinary bioreactors can reach 76.75%.The effect of the applied voltage on the nitrifying bacteria is not very obvious,and under external voltage,the macromolecular hard-to-degrade organic matter in the electrobioreactor is degraded into small molecular organic matter that is easily absorbed by microorganisms,which promotes the growth of aerobic heterotrophic bacteria,thereby The removal efficiency of microorganisms to CODcr is improved.In the stable operation phase,the effects of different external voltages and inlet pH on the electrobioreactor were studied.The research results show that the voltage has a significant effect on the removal rate of CODcr,ammonia nitrogen and total nitrogen.When the external voltage is 2.0V,the electrobioreactor has the best removal effect of CODcr,up to 76.6%.The electrobioreactor The removal rate of intermediate ammonia nitrogen ranges from 52.83% to 71.04%,with an average removal rate of 64.22%.At this time,the reactor has the best removal efficiency of ammonia nitrogen,and the removal rate can be increased by 24.76%.The optimal voltage for removing total nitrogen is 4V.At this time,The average removal rate of TN in the electrobioreactor is the highest,and the removal effect is the best,which can reach 31.15%,which can be increased by 6.05% relative to the unconnected voltage.Under the external voltage,the pH of the inlet water has little effect on the removal of CODcr.The pH of the inlet water is in the range of 6-9.The electrobioreactor has a good removal effect of CODcr,and the removal rate can reach 76.6%.The effect on the removal effect of NH3-N is more obvious.The pH tolerance of the microorganism is increased by applying an external voltage.When the pH of the inlet water is 8.0,the ammonia nitrogen removal effect is the best in the reactor,and the removal rate can reach 67.18%.The high-throughput sequencing technology was used to comparatively study the microbial diversity of the cathode biofilm and anode biofilm in the bioreactor,the biofilm in the common bioreactor,and the biofilm system in the pilot test,and the microbial community inoculated with activated sludge.The comparative analysis of the diversity shows that the application of an appropriate voltage can produce a positive stimulus to most microorganisms in the electric bioreactor,which promotes the growth of new species,thereby increasing the richness and diversity of the microorganisms.Five groups of samples the diversity of the bacterial community is AC>WY3>WY4>WZ>BT,and the richness of the bacterial community is WY3>WZ>WY4>AC>BT.The genus level analysis of the bacterial community structure showed that the denitrifying bacteria Saprospiraceae,Flavobacterium,Sphaerotilus,etc.,hydrogen autotrophic denitrifying bacteria Pseudomonas,Thermomonas,Arenimonas,Thauera,denitrifying bacteria Nitrosomonas,etc.were relatively abundant in the electrobioreactor.The degree has been improved.The genus level analysis of the fungal community structure showed that the external voltage could stimulate the growth of Verticillium and Basidiomycota.Verticillium with higher abundance appeared in the anode biofilm sample of the electric bioreactor,and a higher proportion of Basidiomycota appeared in the biofilm in the pilot test reactor.The high-throughput sequencing technology was used to study the dynamic changes of the microbial community in the electro-bioreactor under the weak acidic and weak alkaline feedwater pH.The results show that the pH value of the feedwater has a significant effect on the diversity of the microbial community in the reactor affected,the diversity of the four groups of samples is MOC>MOE>AOE>AOC,and the community richness is AOC>MOC>MOE>AOE.The PCA analysis and PCoA analysis of the four groups of samples showed that the microbial community of the biofilm system of the electric bioreactor was significantly different from that of the control group.By changing the pH value of the incoming water,the microbial community structure in the electric bioreactor was less affected,Only changed the relative abundance ratio of microorganisms,and the voltage applied to the microorganisms in the electro-bioreactor improved the ability to resist pH changes.The relative abundance of the genera Saprospiraceae,Anaerolineaceae,Flavobacterium,Rhodoferax,Thermomonas,Hydrogenophaga,Acidovorax,Arenimonas,etc.increased significantly when the influent pH was weakly acidic.When the influent pH was weakly alkaline,Sphaerotilus,Saprospiraceae,The relative abundance of functions such as Anaerolineaceae,Flavobacterium,Rhodoferax,Thermomonas,Hydrogenophaga,Nitrosomonas,etc.has increased significantly. |
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