厌氧正渗透膜生物反应器的膜污染机理及其控制措施的研究

发布时间：2018-04-10 09:31

  本文选题：厌氧膜生物反应器　切入点：正渗透　出处：《江南大学》2017年硕士论文

【摘要】：作为一种新型的膜生物反应器技术,厌氧正渗透膜生物反应器(AnOMBR)受到越来越多的关注。AnOMBR采用正渗透(FO)膜替换传统厌氧膜生物反应器(AnMBR)中的微滤(MF)膜或超滤(UF)膜。与传统的AnMBR相比,AnOMBR借助FO膜的高效截留性能,出水水质更好,可以直接进行回用;由于FO膜的低污染特性,在一定程度上缓解了膜污染。然而,AnOMBR仍然存在着盐度积累和膜污染等问题。本文主要针对AnOMBR中的FO膜污染,在采用MF膜缓解盐度的基础上构建稳定运行的AnMF-OMBR装置,考察膜污染对通量衰减的贡献,从有机污染、无机污染以及生物污染等方面全面解析FO膜污染机理,探索物理清洗和化学清洗对FO膜污染的控制效果,最终构建AnMF-OMBR中FO膜污染的控制措施。主要研究内容和结果如下:(1)基于MF膜允许溶解性盐透过的特性,将MF膜与AnOMBR进行耦合构建AnMF-OMBR,在盐度控制的基础上探索FO膜污染的机理及其对通量衰减的贡献。结果表明,MF膜的加入能够有效的控制盐度积累,在AnMF-OMBR的整个运行过程中盐度始终维持在2-3 mS/cm。由于聚酰胺材质的FO(TFC-FO)膜对总有机碳(TOC)和总磷(TP)具有较好的截留性能,出水中的TOC和TP的浓度分别小于4 mg/L和0.5 mg/L。然而,由于氯化钠(NaCl)作为汲取液时FO膜两侧发生了唐南平衡,TFC-FO膜对氨氮(NH4+-N)没有任何截留。TFC-FO膜在AnMF-OMBR中遭受了严重的膜污染,导致TFC-FO膜的通量从7.99 LMH衰减到2 LMH。对膜污染的分析结果表面,TFC-FO膜的污染主要以有机污染和生物污染为主,且生物污染的主要组分是微生物、蛋白质和α-D-吡喃多糖。(2)探索TFC-FO污染膜的水冲洗、超声清洗、物理反冲洗和周期性清洗等物理清洗手段对膜通量恢复的效果。结果表明,水冲洗不能去除TFC-FO膜表面的污染物。超声清洗虽然可以去除膜污染物,但是会破坏TFC-FO膜的完整性,也不适用于TFC-FO膜污染的清洗。在物理反冲洗和周期性清洗都无法恢复TFC-FO膜的过滤性能。(3)考察柠檬酸、盐酸(HCl)、氢氧化钠(NaOH)、十二烷基硫酸钠(SDS)、乙二胺四乙酸二钠(EDTA-2Na)和过氧化氢(H2O2)六种常用化学清洗剂对TFC-FO污染膜的清洗效果。结果表明,柠檬酸、HCl、NaOH、SDS和EDTA-2Na对膜污染的去除效果不佳,而H2O2可以有效地恢复TFC-FO污染膜的通量。进一步对H2O2的清洗条件进行优化,结果发现,最佳的化学清洗方案为使用0.5%的H2O2在25℃下清洗6 h,,清洗后的TFC-FO膜初始通量几乎恢复到新膜的水平。将化学清洗后的TFC-FO膜重新放入AnMF-OMBR中运行,其通量下降速率与新膜相似,对TOC、TP以及NH4+-N的去除效果与新膜一致。这说明经过H2O2清洗后的TFC-FO膜完全恢复了新膜的水平,可以继续应用于AnMF-OMBR的运行。
[Abstract]:As a new membrane bioreactor (MBR), Anombor membrane bioreactor (AnOMBR) has attracted more and more attention. AnOMBR has been used to replace the microfiltration membrane (MF) or ultrafiltration membrane (UFF) in the traditional anaerobic membrane bioreactor (AnMBR).Compared with the traditional AnMBR, Ano MBR has better effluent quality and can be reused directly with the help of FO membrane, which can alleviate the membrane fouling to some extent because of the low fouling characteristics of FO membrane.However, AnOMBR still has some problems such as salinity accumulation and membrane fouling.Aiming at FO membrane fouling in AnOMBR, a stable AnMF-OMBR device was constructed on the basis of using MF membrane to alleviate salinity, and the contribution of membrane fouling to flux attenuation was investigated.The mechanism of FO membrane fouling was analyzed in the aspects of inorganic pollution and biological pollution. The control effect of physical cleaning and chemical cleaning on FO membrane fouling was explored. Finally, the control measures of FO membrane fouling in AnMF-OMBR were constructed.The main contents and results are as follows: 1) AnMF-OMBR is constructed by coupling MF membrane with AnOMBR based on the characteristics of MF membrane allowing soluble salt to permeate. The mechanism of FO membrane fouling and its contribution to flux attenuation are explored on the basis of salinity control.The results showed that the addition of MF membrane could effectively control the salinity accumulation, and the salinity remained at 2-3 MS / cm ~ (-1) during the whole operation of AnMF-OMBR.The TOC and TP concentrations in the effluent were less than 4 mg/L and 0.5 mg / L, respectively, due to the good retention properties of the polyamide-based FOA TFC-FOO membrane for total organic carbon (TOC) and total phosphorus (TP).However, when sodium chloride was used as the solution, the Tangnan equilibrium TFC-FO membrane had no serious membrane fouling in AnMF-OMBR, and the flux of TFC-FO membrane decreased from 7.99 LMH to 2 LMH.The results of membrane fouling analysis showed that the fouling of TFC-FO membrane was mainly caused by organic and biological pollution, and the main components of biological pollution were microorganism, protein and 伪 -Dpyran polysaccharide. 2) to explore the water washing and ultrasonic cleaning of TFC-FO contaminated membrane.Effects of physical backwashing and periodic cleaning on membrane flux recovery.The results showed that water washing could not remove pollutants from the surface of TFC-FO membrane.Although ultrasonic cleaning can remove membrane contaminants, it will destroy the integrity of TFC-FO membrane and is not suitable for TFC-FO membrane fouling cleaning.Citric acid was investigated when both physical backwashing and periodic cleaning could not recover the filtration performance of TFC-FO membrane.The cleaning effects of six common chemical cleaning agents, such as hydrochloric acid, sodium hydroxide, sodium dodecyl sulfate, EDTA-2Naand hydrogen peroxide, on TFC-FO fouling membrane were studied.The results showed that the removal of membrane fouling by sodium citrate and EDTA-2Na was not good, while H2O2 could effectively restore the flux of TFC-FO fouled membrane.The cleaning conditions of H2O2 were further optimized. It was found that the best chemical cleaning scheme was to use 0.5% H2O2 at 25 鈩，

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