Research And Design On The Efficiency Of Domestic Sewage Treatment Equipment For Polar Sailing Ships

With the rapid development of maritime trade,the problem of pollution of the marine environment has occurred from time to time.The International Maritime Organization has paid more and more attention to the marine environment,and the emission standards formulated have been continuously improved.Due to the low temperature in the cabin of the polar scientific research vessel(about 15℃),the treated sewage is difficult to meet the discharge standard.In order to meet the IMO emission standards and maintain high-efficiency removal efficiency,a small-scale aerobic-anaerobic membrane bioreactor(O-A MBR)with a processing capacity of100L/d was used to carry out experimental research.First,explore the best operating conditions of the O-A MBR for the pilot plant.The results showed that the optimal volumetric load of the reactor was 1kg/(m~3×d).The lower volumetric load was not conducive to the removal of COD and TN.Relatively increasing the volumetric load could improve the removal effect;in the different oxic period hydraulic retention time test,the highest average removal rate of COD and TN was achieved when HRT was 7h in the oxic section,which were92.18%and 81.88%,respectively;the anaerobic zone containing trace amounts of dissolved oxygen had little effect on the denitrification effect;it was obtained by wavelet neural network simulation.The relative importance of environmental factors provides guidance for the effective regulation of marine membrane bioreactors in the treatment process.To ensure that the O-A MBR of the small-scale test device operates under the best conditions,changed the operating temperature of the reactor,and investigate the removal efficiency of the O-A MBR on pollutants at different temperatures.The results showed that as the temperature decreased,the removal effect of the system on COD and TN gradually deteriorated.In this test,21°C was the best temperature for O-A MBR operation.At this temperature,the stability and compactness of the sludge was high,and the sludge sedimentation was the best.The results of high-throughput sequencing showed that the genus Motoglia and Nitrospirillum were the main functional bacteria of the system.When the operating temperature was 21℃,the relative abundance of bacteria was the highest,and the reactor had the highest removal efficiency.From the perspective of practical application,an engineering prototype O-A MBR with a processing capacity of 2.52m~3/d was developed,the main equipment of the prototype was selected,and the insulation and heating system of the prototype was designed and calculated.Using CFD software to simulate the internal fluid of the prototype,the influence of aeration on the membrane module was studied.Through the analysis of the MBR liquid streamline diagram,it is found that increasing the disturbance can effectively reduce the membrane pollution,and the membrane module can be used to replace the sedimentation tank to achieve the purpose of mud-water separation.