膜生物反应器处理生活污水中膜污染的研究

STUDIES ON MEMBRANE FOULING OF SUBMERGED MEMBRANE BIOREACATOR FOR DOMESTIC WASTEWATER TREATMENT

研究了一体式膜生物反应器膜污染的分类与阻力分布及膜污染的形成与控制。在操作压力0.020MPa,曝气量0.5m3/h,MLSS稳定在6000mg/L左右的条件下,根据达西方程得出膜阻力分布:膜总阻力11.63×108m-1、膜固有阻力1.69×108m-1、污泥沉积层阻力6.35×108m-1、浓差极化阻力1.8×108m-1;采用临界压力0.020MPa恒压操作方式,低压恒流可以减缓膜污染的形成,但膜通量比较低,采用次临界恒通量12L/m2·h的操作方法,可较为有效地控制膜污染的增长;通过对抽、停间歇操作对可逆污染的控制的研究确定了较理想操作方法,即抽吸时间13min和停抽时间2min;针对不可逆污染,探索了在线药洗的去除效果,用1%的NaC1O浸泡2h,通量恢复效果较好。

A submerged membrane bioreactor was used to treat domestic wastewater; differentiation of membrane fouling, distribution of membrane resistance, membrane fouling formation and membrane fouling control were studied. Under the conditions of trans-membrane pressure of 0.020MPa, aeration amount of 0.5m^3/h, MLSS concentration of about 60000mg/L and according to the Darcy＇s law, the following distribution of membrane resistance can be derived： total resistance of 11.36×10^8m^-1, inherent membrane resistance 1.69×10^8m^-1, cake resistance 6.35×10^8m^-1, concentration polarization resistance 1.8×10^8m^-1; adopting constant pressure operational way with critical pressure of 0.020MPa, low pressure and constant flow can lessen the membrane fouling rate efficiently, but the membrane flux is low; adopting the constant membrane flux operational way with sub-critical constant flux of 12L/m^2·h can control the membrane fouling; more ideal operational method can be determined through the studies of fouling control by drawing and stopping intermittent operation with drawing time 13min and stopping time 2min. Aiming at irreversible fouling, the removal effect of on-line chemical washing was approached; the membrane was soaked for 2h with 1% NaClO solution, the effect of membrane flux recovering was better.