低成本自养脱氮MBR研究
为降低膜的投资成本并实现高效脱氮能力,通过结合MBR和生物膜反应器的技术优势,课题组研发了低成本复合生物反应器(NWHBR)。在NWHBR中滤饼层或生物膜除起到强化截留颗粒物和降低COD外,其主要优势在于强化氨氮、硝态氮和亚硝态氮等在生物膜内的传质和生化过程,进而增强氮的脱除率。在NWHBR运行过程中,生物膜内氮气的生成和逸出有助于保证生物膜的透水能力、降低膜污染速率。每20-30天进行物理反洗可维持膜组件稳定的透水性能。NWHBR反应器在ANAMMOX工艺的启动和运行方面具有更为显著的技术优势。该反应器的脱氮效率比传统生物膜反应器高10-27%。尽管ANAMMOX菌主要以生物膜的形态附着在膜组件上,但是在400多天的连续运行过程中膜组件一直处于无污染状态(即未检出TMP)。一方面ANAMMOX具有较快的反应速率,氮气的逸出会保证生物膜的透水性;另一方面,ANAMMOX菌的EPS与普通活性污泥的EPS显著不同,其所富含的α-螺旋蛋白质二级结构有助于形成ANAMMOX颗粒,从而保证生物膜的透水性。因此,NWHBR工艺不仅具有较低的投资成本,而且有望实现膜组件的低污染或无污染运行。在实验室研究基础上,科研团队逐渐将自养脱氮工艺应用于水产加工废水和垃圾渗滤等高氨氮废水的处理。近期,中山大学“千人计划”陈光浩教授、吕慧教授和孟凡刚教授等人组建和运行了高效亚硝化SBR+厌氧氨氧化MBR的中试工程,用于垃圾渗滤液的高效脱氮处理。
总结与展望
近年来,课题组主要在膜污染物形成机制的解析、膜污染控制新方法的建立和新型MBR工艺的研发三方面开展工作。在分子尺寸和蛋白质水平上阐明了膜污染物的来源,基于UV-Vis特征光谱参数建立了膜污染评估新方法,提出了有效的MBR反洗方法。在技术层面上,研发了具有高效脱氮功能、低膜污染速率和低成本特点的新型MBR,并开展了应用和中试研究。
未来,膜污染问题依然是MBR领域的重要研究方向。随着对膜污染认识的深入和先进分析方法的出现,科研人员将会更多地关注膜污染微观机制。例如,生物大分子生成与降解的分子生物学机制、微生物或生物聚合物与膜材料的相互作用机制等。在膜污染控制方面,研发低污染膜材料、优化曝气方式、调控微生物种群等无疑是减缓MBR膜污染、降低运行能耗的重要途径。在工程应用方面,MBR的应用领域也将更加多样化(如:市政污水的厌氧处理)。
参考资料
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