Research And Application Of Micro/Nano Aeration System

Aeration oxygenation is one of the main methods for black and odorous water body repairment.In this paper,a set of micro-nano aeration oxygenation system was developed,and the numerical simulation of the equal-diameter pitch spiral watershed in the device was performed.The performance indicators of aeration oxygenation device were determined and the relevant models were established,and the comparison between the common aeration oxygenation equipment and the developed micro-nanobubble aeration device was conducted.The pollutants removal of SBR system based on micro-nanobubble aeration device and aerated plate aeration was investigated,and a demonstration project was carried out.The Meshing software was used to mesh the SolidWorks modeling files.Assembled ladder-type edge model grid is more than twice the smooth model.The assembled model can express variable spiral pitch and stepped edge,fully reflecting the characteristics of the basin.At the same time,Realizable k-εturbulence model,mixture model,no-slip wall and SIMPLEC algorithm were selected,and the 420-step convergent solution was achieved.The numerical simulation results showed that the fluid in the watershed has obvious rotational motion along with varying pitch spirals.The blade cutting and variable helix spiral structure in the basin make the gas-liquid mixture passing through the basin mix evenly.The pressure drop in the basin from the inlet to the outlet was obvious.The diversion cone can act as a shunt and pressure equalizer.The mixed cutting action of the blades around the equal-diameter-pitch spiral orifice increases the pressure,velocity,and mixing degree of the gas-liquid two phases,and increases the degree of turbulence,which contributes to the gas-liquid mass transfer,the refinement of bubbles,and the formation of micro/nano bubbles.Based on Central Composite Design theory to design three factors and five levels test.The effects of gas flow rate A,liquid flow rate B,water depth C on the standard oxygen total transfer coefficient Y1,oxygen utilization rate Y2,and theoretical power efficiency Y3 were analyzed.Three regression quadratic regression models were obtained.The primary and secondary factors that affect Y1,Y2,and Y3 are:liquid flow>water depth>gas flow,liquid flow>gas flow>depth of water,liquid flow>gas flow>depth of water.The effect of liquid flow X2 on Y1 was significant.gas flow X1,liquid flow X2,and X1X2 had a significant effect on Y2,and gas flow X1,depth of water X3,and X3X3 had a significant effect on Y3.The above indicators were statistically significant for the corresponding response values.comprehensive analysis of multiple factors to optimize to obtain the standard oxygen transfer coefficient,oxygen The optimal process parameters for utilization and theoretical power efficiency are oxygen flow 0.5m³/h,liquid flow 10m³/h,and water depth 0.3m,Through the model prediction calculations:the standard oxygen transfer coefficient of 1.4394,oxygen utilization rate of 37%,the theoretical power efficiency of 7.4388kgO₂/kw·h,the experimental verification model is reasonable.Compared with common aeration equipment,the new micro-nanobubble aeration device has obvious advantages in aeration and oxygenation performance,low cost,high efficiency and low consumption,and is not easy to block,easy to repair,and suitable for a wide range of water bodies.It is worthy of promotion and application.The micro-nanobubble aeration device can reduce the pollution load,enhance the self-purification capability of the water body,restore the healthy water ecosystem,and eliminate the black and odor by aeration,oxygenation,and cutting refinement.Comparing the results of micro-nanobubble aeration device and aerated plate aeration for SBR treatment of black and odorous water,we can see that the removal efficiency of COD,ammonia nitrogen,nitrate,TN,and TP in the micro-nanometer aeration group is higher than that of the aeration tank aeration,respectively.The average group height was 20%,20%,17%,38%,and 35%.The variable-pitch spiral structure of the micro-nanobubble aeration device can cut and refine the contaminants,bubbles,liquids,etc.flowing through the device system,so that the pollutants,microorganisms,and oxygen can be fully mixed,and the system can obtain better pollutant removal effect.Two demonstration project operations of the micro-nano aeration oxygen system showed that the system had a good effect on the water quality,and overall water quality has been improved from the inferior V class water standard to the class V water standard.