Study On Magnetic Field Regulation Of Nitrate Accumulation In Partial Denitrification

Focusing on the regulation of nitrous nitrogen accumulation in short-range denitrification,based on the magnetic effect of microorganism,the characteristics of nitrous nitrogen accumulation in short-range denitrification system were studied.Field distribution and characteristics of magnetic field in reactor were measured in different magnetic field methods of magnetic powder,magnet and wire coil,nitrogen conversion,nitrous nitrogen accumulation rate?NTR?,dehydrogenase activity and surface morphology characteristics were studied.The effects of magnetic field on nitrous nitrogen accumulation in short-range denitrification system were investigated.The results show that when the magnetic reactor is constructed by adding magnetic powder,the magnetic field strength is relatively smaller than that of other magnetic fields in the range of 0-0.38 mT,and the magnetic field strength is seriously attenuated in the short term;the magnetic field formed by the single magnet and the double magnet As the distance increases,the intensity drops sharply,and the magnetic field intensity in the reactor is unevenly distributed.The variation of the magnetic field strength formed by the double magnets inside the reactor is symmetrically distributed,and the intermediate magnetic field strength is weak,and the magnetic field decayes faster with the change of distance,and the magnetic field provided by it is unevenly distributed;The increase of the energizing current continues to increase.At 1A,2A,and 3A,the magnetic field of the inner wall of the coil can reach 21 mT,40 mT,55 mT,and the central magnetic field is weak;add 1,2,3,7,13 iron in the energizing coil,respectively With the increase of the number of cores,the intensity of the magnetic field inside the reactor is gradually distributed evenly.When there are 1,7,12 in the energizing coil,the magnetic field inside the reactor can reach a maximum of 80mT.The iron core is added with a magnetic field,the magnetic field is relatively high,the distribution uniformity is better,and the convenience of adjusting the magnetic field strength is higher.Magnetic field can enhance the accumulation rate of nitrous nitrogen and dehydrogenase activity in short-range denitrification reactions and successfully enrich short-range denitrifying bacteria.when the magnetic field intensity is 50 mT,the maximum accumulation rate of nitrous nitrogen is about 95%,and the highest dehydrogenase activity is 79.86 mgTF/?l·h?when the magnetic field intensity is 35mT.through microbial surface morphology analysis R₁?R₂?R₃ a large number of short bacilli are gathered on the sludge surface,which may be functional bacteria in the short-range denitrification process,and good anaerobic state is maintained in all four groups of reactors.Through high-throughput sequencing analysis,the dominant bacteria in the cultured sludge were the highest in the Thauera,R₃,which was beneficial to the accumulation of nitrous nitrogen in the short-range denitrification reaction under the intensity of the magnetic field.The functional analysis of the microbial community was obtained R₃ which was more conducive to the synthesis and metabolism of glycine organisms and the metabolism of their ability,R₂ more conducive to the transport of membranes.Tthe magnetic field-regulated short-range denitrification system can make the short-range denitrification system operate stably under different volume loads.by gradually optimizing the C/N and pH,the high efficiency and stable nitrous nitrogen accumulation rate can be guaranteed.mT highest nitrous nitrogen accumulation rate was 100%when the volume load of the reactor was about 1.4 Kg/?m³·d?,1.6Kg/?m³·d?,1.65 Kg/?m³·d?,and the initial nitrate concentration was 30 and 70 mg/L.At 5 o'clock,the highest accumulation rate of nitrous nitrogen is about 90%,which is more favorable to the accumulation of nitrite;p H at 8 o'clock,the accumulation rate of nitrous nitrogen is 100%,which is beneficial to the accumulation of nitrite.pH=7and 9,the accumulation rate of nitrous nitrogen was about 90%,that is,the neutral weak alkaline condition was beneficial to the accumulation of partially denitrification nitrite.