用年工业透水率衰减预测MBR膜寿命——以西安思源学院超十年运转为例

Prediction of MBR Membrane Lifetime by Annual Decay of Industrial Permeability—Taking Xi’an Siyuan University’s More than Ten Years Operation Data as an Example

摘要: 定义“工业透水率VMD”为1000 m²单位膜面积在1天单位时间和1 kPa单位膜压差下的m³透水体积。直接采用西安思源学院再生水厂3520天A²/O-MBR系统每日运转的日产水量和膜压差大数据依序计算VMD。剔除五类异常点后得到71%~78%有效VMD。人为地将每25个有效VMD划分为一个组单元，计算组单元的VMD算术平均值。拟合组VMD算术平均值与组单元得直线型工业透水率衰减方程。因为表示VMD算术平均值与组单元比较发散，所以按“年”为划分界限对组单元进行第二次降维得“年单元”，并计算年单元的VMD算术平均值。拟合年VMD算术平均值与年单元得幂型工业透水率衰减方程。用前期的衰减方程预测后一年的工业透水率，用当期的衰减方程实测后一年的工业透水率。定义误差比为预测值与实测值的相对大小。计算年工业透水率衰减是直接、简单且方便。所得结果既可以预测膜寿命，又可以自我学习不断优化，还得出预测时段不应小于三年，最好选择四到五年为宜。

Abstract: Defining “industrial permeability VMD” as the m³ permeable volume of 1000 m² membrane area at 1 day and 1 kPa cross-membrane pressure difference. The VMD is directly calculated by using the daily water yield and cross-membrane pressure difference of 3520 days of Xi’an Siyuan A²/O-MBR system. After excluding five anomalies, 71% to 78% of effective industrial permeability was obtained. Each 25 effective industrial permeability was artificially divided into a group unit by the membrane pool, calculating the VMD arithmetic average of the unit. A linear regressive equation can be got through the VMD arithmetic mean and the group unit. Because it indicates that the arithmetic mean value of VMD is more divergent from the group unit, the group unit is reduced into the annual unit. A power equation is fitted the annual VMD arithmetic mean and the annual unit. The industrial permeability in the following year is predicted by the previous attenuation equation, and the industrial permeability in the following year is measured by the current decay equation. The error ratio is defined as the relative size of the predicted and measured values. Calculating the annual industrial permeability attenuation is straightforward, simple, and convenient. The results can not only predict the membrane life, but also continuously optimize self-learning. It also shows that the prediction period should not be less than three years, so it is best to choose four to five years.