MBR污泥混合液特性变化及膜污染关系研究

Study on change of sludge mixed liquor characteristics and membrane fouling in MBR

考察了长期运行不排泥情况下膜生物反应器(MBR)中的污泥混合液特性变化,并结合Darcy公式探讨污泥性质与膜污染的关系。研究表明,在130 d的运行期间,随着污泥龄(SRT)的增加,污泥浓度增大,混合液粘度增大,污泥的平均粒径从51.56μm增加到92.57μm后略有减小;对比上清液和出水的分子量分布特征发现,膜组件对大分子量物质的截留和膜出水的稳定性有很大贡献,大分子量物质对膜污染的影响大于小分子量物质;随SRT的增大,混合液胞外聚合物(EPS)和上清液溶解性微生物产物(SMP)浓度均呈先增大后减小的趋势,混合液EPS含量越大,污泥比阻值越大,泥饼层透过性能变差,泥饼层阻力(Rc)越大;上清液SMP和膜污染阻力(Rf)呈指数关系,SMP含量增大,Rf增加速度加快,膜污染加剧。

The change of the sludge mixed liquor characteristics with SRT was studied and the effect of the mixture characteristics on membrane fouling in the MBR was also explored by Darcy formula.The results showed that MLSS and the mixture viscosity increased with SRT during the 130 days runtime.Sludge average diameter increased from 51.56 μm to 92.57 μm gradually and then decreased slightly.Membrane assembly appeared good results in removal of large molecular weight organic matter and stability of the effluent quality.And it could be speculated that the effect of the large molecular weight organic substances on the membrane fouling was larger than the small ones.Mixture EPS content as well as the SMP concentration in the supernatant firstly increased and then decreased with SRT.The higher EPS concentration was,the greater the specific resistance of sludge was.The penetrant performance of sludge cake layer deteriorated,and Rc became larger.SMP and Rf took on an exponent relationship,with higher SMP content and faster Rf,while the membrane fouling became worse.