城市污水膜生物反应器处理工程中膜寿命预测

Life-time Assessment of Membrane in Large-scale MBR Plants for Municipal Wastewater Treatment

通过分析3座大型城市污水膜生物反应器(MBR)处理工程(>10 000 m^3/d)的长期运行情况(>3年)及NaClO离线清洗效果,试图建立两种方法对膜寿命进行预测,即基于实际平均比通量下降趋势的膜寿命预测(T(life)-1)和基于离线清洗前后膜渗透性恢复情况的膜寿命预测(T_(life)-2)。结果显示,对于同一座MBR工程,T_(life)-2略大于T_(life)-1,但当膜运行时间达到T_(life)-1时,实际产水量已无法满足要求,因此T_(life)-1更具有实际工程意义。另外,对其中1座MBR工程平均比通量和累积化学清洗强度的关系进行分析,结果表明化学清洗是膜寿命的重要影响因素,可能存在最大化学清洗强度,预示膜寿命终结,有助于膜清洗方案的优化。

To estimate the membrane life-time in engineering application, long-term performance （ 〉 3 years） of three large-scale membrane bioreactor （MBR） plants （ 〉 10 000 m^3/d） and hypoehlo- rite off-line cleaning effects on membrane permeability recovery were analyzed. Two methods, which are based on the reduction of actual average specific membrane flux （ Tlife-1 ） and the permeability recovery after chemical cleaning （Tlife-2） respectively, were proposed to estimate the membrane life-time of the three MBR plants. Compared with Tlife-2, the values of Tlife-1 for the same MBR plant were normally lower but more proper for practical engineering because the effluent flow was unable to satisfy the water production demand when the Tlife-1 reached. Moreover, the relevance between the average specific membrane flux and the cumulative hypochlorite cleaning intensity indicated that membrane life-time was significantly affected by chemical cleaning. A maximum cleaning intensity might be recommended to indicate the end of membrane life-time as well as help to optimize the membrane cleaning procedure.