曝气量对PCMR处理腐殖酸废水中膜污染控制研究

Study on the Control of Membrane Fouling in Humic AcidWastewater Treated by PCMR with Aeration Volume

研究了曝气量对光催化陶瓷膜反应器(PCMR)处理含腐殖酸模拟废水工艺中跨膜压差(TMP)、料液有机物UV254及SUVA、膜污染指数(MFI)及膜污染阻力的影响,考察了空气和渗透液周期性在线反冲去除膜污染效率。结果表明:当曝气量从1.0 L/min增加到5.0 L/min时,光催化氧化效率逐步提高,光催化作用下PCMR工艺运行的MFI低于无光催化时的情况,曝气引起流体湍动及光催化氧化作用对膜污染都具有控制作用,当曝气量从5.0 L/min增加到7.0 L/min时,光催化作用对PCMR工艺中膜污染控制的效果相差不大,流体高湍动冲刷作用对膜污染起主要控制作用。PCMR工艺初始阶段膜污染程度较低,后阶段膜污染程度较高,当曝气量较高时,不能有效减缓不可逆膜污染。无论利用渗透液还是空气反冲,第一次反冲后的不可逆膜污染较重,而后多次反冲后的不可逆膜污染变化不大,也不能把第一次反冲后留下的不可逆膜污染消除,且渗透液反冲优于空气反冲的效果。

The effects of aeration rates on transmembrane pressure differences(TMP),UV254 and SUVA of feed,membrane fouling index(MFI),and membrane fouling resistances were analyzed in the process of photocatalytic ceramic membrane reactor(PCMR)for humic acid wastewater treatment.The periodic online backwashing using air and permeate to remove the membrane fouling were also investigated.The results showed that the photocatalytic oxidation efficiency increased gradually with increasing the aeration rate from 1.0 L/min to 5.0 L/min,and the MFIs of the PCMR process were lower than those without photocatalysis.Both of the turbulence caused by aeration and photocatalytic oxidation had effects on membrane fouling mitigation.As the aeration rate reached 7.0 L/min,the effect of photocatalysis on membrane fouling control in the PCMR process was not significant,and the high turbulence characteristics of fluid play a major role in membrane pollution control.The initial stage of the PCMR process showed a lower degree of membrane fouling,while in the later stage,the membrane fouling degree was much higher.The irreversible membrane fouling cannot be effectively removed at the high rate of aeration.Whether using permeate or air for removal of membrane fouling,the irreversible membrane fouling after the first backwashing was much higher serious,and after the second backwashing,the irreversible membrane fouling did not change much and the irreversible membrane fouling after the first backwashing could not be eliminated.The efficiency of backwashing using permeate was better than that of using air.