微滤分离膜在城市污水深度处理中的应用

Municipal wastewater advanced treatment by using micro-filtration membrane

采用微滤分离膜系统对污水处理厂生物处理的出水进行深度处理中试试验研究 ,以满足污水多用途回用。试验在恒定过滤流量( 4 .5 m3/ h)和错流速率 ( 0 .1m/ s)条件下进行。研究表明 ,分离膜在运行过程中 ,流体学阻力 R随运行时间延长呈指数增加 ;污水的化学生物特性和流体动力学特性都对污染速率 ( d R/ dt)有影响 ,其中化学生物特性影响是主要的。生物处理系统的二级出水经过 MF膜分离系统处理后 ,悬浮物小于 5 mg/ L,浊度小于 0 .5 NTU,细菌和大肠杆菌几乎全部去除 。

The present paper aims to introduce the author's innovated advanced treatment of the municipal sewage water by means of a membrane filtration process of MF (Micro-filtration). So far the given treatment enjoys the advantages of large volume, concentration and stable quality in recycling of the municipal potential water resource with the desirable efficiency as a result of the pilot scale trial use in Tianjin Economic Technical Development Area Sewage Treatment Plant. While the sewage water treatment by MF membrane separation system, the hydraulic resistance would increase as a function of running time in an exponential manner, and hydraulic resistance can be expressed as R= (1.97 + 0.033×e^(\%t\%/4.49))×10^(12). Also, the TMP (trans-membrane pressure) showed that the similar character with the time as the hydraulic resistance in the separation filtration process. The fouling velocity, measured as d\%R\%/d\%t\%, decreased with \%(τ_0/ρJ^2)\%in an exponential manner. The chemical and biological characteristics of SBR secondary effluent, and the running hydrodynamic condition affected the fouling velocity, and the chemical and biological characteristics seem to be more dominant than the hydrodynamic conditions in the filtration. Our experiments show that the MF membrane system runs successfully, and the MF system effluent had good quality with the SDI (slit density index) value small than 3, the suspended solid concentration below 5 mg/L, and the turbidity values below 0.5 NTU, and the bacteria almost none. So the result of pilot-scale test can be said highly satisfactory. Therefore, the present advanced treatment can be regarded as a model of utilizing and protecting water resources in the nation-wide sphere, which is expected to manifest its great social, economic and environmental benefit in the future practical application.