Application Of New Microbubble Generator In Treating Polluted Water

Aeration system is not only one of the core units of aerobic biological treatment,but also an important means of remediation of polluted water.Its oxygenation performance directly affects the effect of microbial treatment and energy consumption.A new type of micro bubble generator with high efficiency and low consumption was developed in the field of water treatment.The parameters of bubble suspension time,effective gas liquid mixing ratio and bubble diameter were determined by the bubble test,and the concentration of saturated dissolved oxygen,the total transfer coefficient of standard oxygen and the oxygen filling capacity were determined by the water filling test.Oxygen utilization rate and other parameters.The repair effect of new micro bubble generator in urban sewage,landscape water and black odor water was also investigated.On this basis,the analytic hierarchy process is used to evaluate the new micro bubble generation device and ordinary aeration device,and the water body suitable for the device is obtained,and the economic benefit value of the new device is further discussed.In this study,a novel microbubble generating device suitable for water treatment was developed using the principle of dissolved gas release.The device abandons the large dissolved gas outgassing equipment required by traditional dissolved gas outgassing method and adopts a self-intake air intake method,thereby reducing the volume,energy consumption,and cost of the entire device.In addition,self-priming air intake method is adopted to further improve the gas supply method of the air pump,thereby reducing the volume,energy consumption,and cost of the entire device.In addition,the device adopts a pressure flow outlet method,which can not only enhance the partial pressure of oxygen,improve the efficiency of oxygen mass transfer,but also has the ability to cut and refine macromolecular contaminants in the water,so that the microorganisms,pollutants and dissolved oxygen can be fully mixed.In contact,the microbial activity is further enhanced and the ability to remove contaminants is increased.The results of the new micro-bubble generating device bubble generation test show that the new device can produce a milky white mixture,the air bubble suspension time is 1 minute 34 seconds,the effective gas-liquid mixture ratio is 5%,and the diameter of the bubble is less than 72μm,accounting for 50%of the total amount of the bubble.The results of clear water oxygenation test show that the new micro bubble generating device has better oxygenation performance and is obviously superior to the comparative equipment.The new micro bubble generating device has an intake volume of 1.5 L/min,a saturated dissolved oxygen of10.5 mg/L,a standard oxygen transfer coefficientof 0.4681,an oxygenation capacity₍（8） of 0.0515 kg/h,and an oxygen utilization rateεof 37.47%.The new microbubble generator in the treatment of black and smelly water,landscape water and landscape water shows that the aeration effect of the new micro bubble generator is obviously superior to the ordinary aeration device.It can improve the dissolved oxygen environment of the water body quickly and effectively,and keep the concentration of DO at a high level.（1）The results of aeration contrast test in black odor water body are as follows:the removal rates of CODcr,NH₄⁺-N,TP,TN and Geosmin in the microbubble aeration group were 80%,72%,80%,10%,60%.The concentration of DO is increased from 0.41 mg/L to 10.78mg/L,and the concentration of NO₂^--N first increases and then decreases,and the NO₃^--N concentration accumulates to 9.87 mg/L;the NO₃^--N concentration is 9.87 mg/L;The removal rates of CODcr,NH₄⁺-N,TP,TN and Geosmin in the ordinary aeration group were 70%,58%,65%,10%and 48%.The concentration of DO increased from 0.41 mg/L to 7.93mg/L,and the concentration of NO₂^--N was basically unchanged,and the concentration of NO₃^--N accumulated to 10.21mg/L.（2）The results of aeration contrast test in landscape water are as follows:the removal rates of CODcr,NH₄⁺-N,TN and TP in the microbubble aeration group were70%,43%,30%and 72%.The concentration of DO increases from 0.41 mg/L to11.97mg/L,and NO₂^--N rises first and decreases,changes smaller,NO₃^--N concentration accumulates to 0.16 mg/L,Chl-a concentration accumulates to 0.012 mg/L;The removal rates of CODcr,NH₄⁺-N,TN and TP in the ordinary aeration group were 50%,22%,18%and 48%respectively.The concentration of DO increased from 10.2 mg/L to 10.78mg/L,the concentration of NO₂^--N was basically unchanged,the concentration of NO₃^--N accumulated to 0.12 mg/L,and the Chl-a concentration accumulated to 0.011 mg/L.（3）The results of comparison test of domestic sewage aeration are as follows:CODcr,NH₄⁺-N,TP and TN removal rates of microbubble aeration group were 71%,42%,58%and8%.The concentration of DO increased from 0.41 mg/L to 9.78mg/L,and the concentration of NO₂^--N was basically unchanged,and the concentration of NO₃^--N accumulated to 6.69 mg/L.The removal rates of CODcr,NH₄⁺-N,TP and TN were 54%,28%,39%and 8%in the ordinary aeration group,the concentration of DO increased from0.41 mg/L to 5.72mg/L,NO₂^--N concentration increased first and then decreased,and the NO₃^--N concentration increased to 3.47 mg/L.By investigating relevant literature and combining relevant data,a set of index evaluation system about aeration device is constructed,and then the corresponding weight of each index is obtained by analytic hierarchy process.Finally,the new micro bubble generator and ordinary aeration device are evaluated.The total weights of the new micro bubbles in the treatment of black and smelly water,landscape water and urban sewage were first,third and fourth,respectively.The total weight of black and smelly water,landscape water and domestic sewage treated by ordinary aeration equipment were second,fifth and sixth respectively.Although the ordinary aeration device shows advantages in machine cost,price,power consumption and performance,it is poor in performance and treatment effect and low in energy efficiency.The weight sorting of the new device is better than that of the conventional aeration equipment.For the sewage treatment field,the new device should have more room to play.