Application Research Of MBR In Refining Sewage Treatment

Petroleum refining industry is one of the industries with high water consumption,which results from the scale of production and technology of the enterprise.According to the national development strategies of energy saving,water-saving and emission reduction,petrifaction enterprises needs to not only reach the national pollutant discharge standard,but also save water,do a good job in total quantity controlling of pollutants and improve the rate of reused water.Membrane Bioreactor(MBR)is one of the mainstay technologies for water treatment in the field of wastewater treatment,and it is advantageous over traditional methods on smaller floor coverage,higher purification efficiency,higher MLSS concentration,longer sludge retention time,less sludge production,better effluent quality,easier for water cycling,strongerresistance to shock loading,more flexible manipulations and so on.However,the majordifficulties of the MBR technology on petrochemical refinery wastewater treatment are how to control the membrane fouling rate,keepingthe membrane flux and establishingan effective method for membrane cleaning.This subject aims to discuss the traits and advantages of MBR technology through analyzing the operating data of MBR technology and traditional oxidation ditches technologyin a refining company sewage treatment plant in SINOPEC,through comparing the removal rate of major contaminant in treated reclaimed water including CODcr,NH3-N,conductivity,turbidity and so on.We also propose some recommendations and programs for improvement and optimizationin allusion to the deficiencies of MBR technology.Results are shown as follows:1.MBR technology is an advanced sewage treatment method with advantages of small occupation of land,high rate of reaching to standards of discharged water,auto-operation and so on.The majorcontaminant factors of CODcr,NH3-N,SS etc.in treated reclaimed water all meet the Level 1 emission standard requirements in Integrated Wastewater Discharge StandardGB8978-1996 and reach the standard forrecycling from company.2.MBR technology for sewage treatment uses membrane separation technique instead of secondary sedimentation tank and sand filter in normal activated sludge process,which leads toshorter process,concentrated equipment layoutand thus less occupation of land.3.Using permselectivity of membrane realizes the enrichment of microbial community,which keeps high concentration of sludge and biotic population that promotes the efficiency of biotreatment and effectiveness of removing CODcr、NH3-Nand SSand lead to qualified and stable water emission.4.MBR technology can not only be controlled flexibly and stably but also can realize auto-controlled easily.Sludge can be retained in reactor area under the intercept of membrane which makes it possible to control the time of reactor hydraulic retention and solids retention separately,thus realizing the flexible control of these two parameters.In addition,it is beneficial to realize the infrastructure integration and good for auto-control.5.The key points for the operation of MBR technology are how to address the decrease of MBR membrane flux and cleanout and take good care of membrane component.