FeCl_(3)对AnMDBR废水净化效能和膜污染影响的研究

Study on the effect of FeCl_(3) on the purification efficiency and membrane fouling of AnMDBR wastewater

废水的资源化回用是目前废水处理的重点.本文考察了在高温环境下(55℃),投加低浓度(20 mg/L)、中浓度(50 mg/L)和高浓度(100 mg/L)FeCl_(3)对厌氧膜蒸馏生物反应器(AnMDBR)处理废水的污染物净化、产水效能和膜污染的影响及相关机理.结果表明,3种FeCl_(3)投量对AnMDBR中COD、NH+4-N和P的去除效能没有显著差异,平均去除率分别达到98.12%、81.80%和99.99%以上.然而,投加FeCl_(3)能够提升产水通量,通量增幅依次为50 mg/L>100 mg/L>20 mg/L.这是因为适当投加FeCl_(3)改变了污泥特性,增大了Zeta电位、颗粒粒径和EPS含量,同时减少了SMP浓度,从而使污泥更易团聚.此外,污泥及其代谢产物在FeCl_(3)的混凝作用下在膜表面形成更为疏松多孔的滤饼层结构,但过高投量会加剧膜的无机污染.另外,投加FeCl_(3)提高了微生物群落中Methanothermobacter的相对丰度,有利于产甲烷过程进行.本研究结果为投加铁盐混凝剂强化AnMDBR废水处理效能提供支持.

Resourceful reuse of wastewater is currently the focus of wastewater treatment.In this study,the impact of contaminant purification,water production,membrane fouling,and underlying mechanisms within a high-temperature(55℃)anaerobic membrane distillation bioreactor(AnMDBR)was examined,using three FeCl_(3) dosages(20 mg/L,50 mg/L,and 100 mg/L).The results showed that there was no significant difference in the removal efficiencies of COD,NH_(4)~+-N and P across the three FeCl_(3) dosages,with average removal rates exceeding 98.12%,81.80%and 99.99%,respectively.However,an increase in water production was observed,with the order of effect being 50 mg/L>100 mg/L>20 mg/L.This phenomenon was attributed to the modification of sludge characteristics by FeCl_(3),which included the augmentation of Zeta potential,particle size,and EPS concentration,while simultaneously leading to a reduction in SMP concentration.The alteration facilitated sludge agglomeration.Additionally,the formation of a loose,porous cake layer on the fouled membrane is achieved through the proper addition of FeCl_(3).Nevertheless,inorganic fouling of the membrane was exacerbated by excessive FeCl_(3) addition.Furthermore,FeCl_(3) addition increased the relative abundance of Methanothermobacter in the microbial community of AnMDBR,thereby promoting the methanogenesis process.These findings provide support for improving the wastewater treatment performance within iron salt-assist AnMDBR.