水平搅拌下低高径比SBR中好氧活性污泥的颗粒化

中国环境科学2018,38(9)：3358~3366ChinaEnvironmentalScience水平搅拌下低高径比SBR中好氧活性污泥的颗粒化曲新月,范文雯,袁林江*,张瑞环,魏萍(西安建筑科技大学,陕西省环境工程重点实验室,教育部西北水资源环境与生态重点实验室,陕西西安710055)摘要：在设有水平机械搅拌、高径比(H/D)为1.2的圆柱形鼓风曝气SBR中,考察了活性污泥的颗粒化情况,对成熟颗粒污泥表面所受水力剪切速率进行了定量研究,分析了水平搅拌在颗粒化过程中的作用.结果表明:有水平搅拌存在下污泥逐渐颗粒化,形成了均值粒径为1.12mm的好氧颗粒污泥,污泥沉降速度为21.41m/h;计算结果表明污泥表面所受的平均剪切速率为27.25s-1,剪切应力为3.38×10-2N/m2;污泥表面所受平均剪切速率与机械搅拌速率和表观气速均呈正相关关系;实验条件下机械搅拌对剪切速率的贡献要远大于表观气速的贡献,前者指数约为后者的37.48倍.研究认为水平搅拌在反应器中形成的具有足够剪切强度的旋涡二次流是促使低高径比反应器好氧污泥颗粒化的关键水力条件.关键词：好氧颗粒污泥；低高径比；水平机械搅拌；水力剪切中图分类号：X703文献标识码：A文章编号：1000-6923(2018)09-3358-09AerobicsludgegranulationunderhorizontalmechanicalagitationinaSBRwithlowerratioofheighttodiameter.QUXin-yue,FANWen-wen,YUANLin-jiang*,ZHANGRui-huan,WEIPing(KeyLaboratoryofEnvironmentalEngineering,ShaanxiProvince,KeyLaboratoryofNorthwestWaterResources,EnvironmentandEcology,MinistryofEducation,Xi’anUniversityofArchitectureandTechnology,Xi’an710055,China).ChinaEnvironmentalScience,2018,38(9)：3358~3366Abstract：AerobicsludgegranulationwasinvestigatedinahorizontalmechanicalstirredandaeratedSBRwithlowerratioofheighttodiameter(H/D)of1.2.Theaverageshearratethatgranulessufferedwascalculatedandtheeffectofhorizontalagitationonthegranulationprocesswasdiscussed.Theresultsshow,theaerobicsludgewasgranulatedinthereactorwithameandiameterof1.12mmandsettlingvelocityof21.41m/hfinally.Theaverageshearrateofgranuleswascalculatedoutas27.25s-1,andtheshearforce3.38×10-2N/m2.Theaverageshearrateactedonthesurfaceofthegranulespositivelyrelatedtomechanicalagitationspeedandsuperficialgasupflowvelocity,ofwhichthemechanicalagitationspeedcontributedmoretotheshearrate,about37.48timesofthatthesuperficialgasupflowvelocitydid.Itwasconsideredthattheeddysecondaryflowpatternwithappropriateshearforcecausedbytransverserotationofstirrerwasessentialtoaerobicsludgegranulationinthereactorwithlowerratioofheighttodiameter.Keywords：aerobicgranularsludge；lowratioofheighttodiameter；horizontalmechanicalstirring；hydrodynamicshear好氧颗粒污泥形状规则、结构密实、沉降性好、抗冲击负荷能力强[1-2],在废水生物处理中具有明显的应用