Optimization Design Of Marine Membrane Bioreactor And Its Denitrification And Carbon Removal Efficiency

With the increase of marine environmental pollution,countries around the world have paid more and more attention to the marine environment,and the sewage discharge indicators have been continuously improved.In addition,the harsh ship environment is a big challenge for ship sewage treatment.Compared with other ship sewage treatment equipment,the marine membrane bioreactor(MBR)has the advantages of strong stability,strong impact-resistance and small volume,and has attracted much attention.However,marine MBR can still be further optimized:improving efficiency and reducing membrane fouling.Therefore,an external MBR reactor and its improved MBR reactor were studied to investigate the effect of conventional factors on its nitrogen and carbon removal efficiency,and the optimized reactor was analyzed by comparison before and after optimization.Advantages and disadvantages.For external MBR reactors,increasing the influent volumetric load was beneficial to the removal of chemical oxygen demand(COD).When the load reached 1.6 kg/m~3·d,the COD removal rate reached 94.98%.However,too low load affected the growth of the organism,which in turn affects the removal rate of COD,and whether the carbon source was sufficient for its total nitrogen(TN)removal efficiency was critical.When the influent carbon to nitrogen ratio(C/N)was 12:1,the TN removal rate reached 83.38%,the membrane module had almost no removal efficiency for TN and COD.The improved MBR reactor was obtained by optimizing the structure and operation mode of the external reactor,and structurally distinguishing the single biochemical of the external reactor into a combination of aerobic zone and anaerobic zone,and operating the membrane.The combination of components and anaerobic zones created a unique operating environment.For the improved MBR reactor,the COD removal efficiency of the reactor had been maintained at a high level of 92%to 94%under the inlet volume load of 0.8-1.6 kg/m~3·d,and the removal efficiency of TN was relatively stable.The volumetric load of water was less affected and has been maintained at a high level of 88.8%to 91.7%.Especially at low loads,it still had high removal efficiency.The TN removal rate of the reactor increased first with the decrease of influent C/N.The larger and then reduced,and the best TN removal rate of 87.1%was obtained when the influent C/N=12:1.The advantage of the optimization was that the adjustment ability against the influent COD impact was enhanced,the removal efficiency of COD and TN was obviously improved,the removal efficiency was better in the low influent volume load,and the influence on the inlet volume load was smaller,and the performance was more stable.Although the fouling of the improved MBR reactor membrane module was slightly heavier,it was still within an acceptable range,and the processing guarantee and efficiency of the membrane module to the system were improved.In general,the improved MBR reactor had better denitrification and carbon removal efficiency than the external MBR reactor.