硝酸盐对氢基质生物膜反应器中溴酸盐和高氯酸盐去除的影响机制

As a conventional contaminant in water, nitrate has become an important factor affecting removals of bromate and perchlorate in a hydrogen-based membrane biofilm reactor (MBfR). How to control the impact of nitrate is a key to improve the performance of MBfR．Study on nitrate influence has been conducted systematically at present, while its nature of the promotion or inhibition was still not clarified. The project aims to investigate the promotion or inhibition mechanism of nitrate on removals of bromate and perchlorate in a hydrogen-based membrane biofilm reactor. Effect of nitrate on transformations and removal efficiencies of bromate, perchlorate and their intermediates will be conducted using a continuous stirred MBfR based on successfully isolating autohydrogenotrophic reducing bacteria. Characteristics of mutual utilization competition and hydrogen consumption competition on nitrate, bromate and perchlorate reduction by microorganisms will be quantitatively analysed by establishing reaction kinetics in the biofilm and a hydrogen utilization quantitative relationship. The change law of the microbial community structure and its relationship of the removals of contaminants will be clarified on a basis of key reductase activity and molecular biology research. The mechnism of nitrate affecting removals of bromate and perchlorate by autohydrogenotrophic microorganisms can be revealed from a different angle. Results obtained from this research is supposed to provide a theoretical foundation on controlling the nitrate influence to achieve the purpose of improving bromate and perchlorate removal efficiencies, and provide a technical support to further optimize MBfR operating parameters.

作为水中常规污染物，硝酸盐成为影响氢基质生物膜反应器（MBfR）中溴酸盐和高氯酸盐去除的重要因素。如何控制硝酸盐影响是提高MBfR处理性能的关键。目前关于硝酸盐的影响效应已有系统研究，但其促进或抑制作用本质仍未厘清。本项目旨在研究硝酸盐对MBfR中溴酸盐和高氯酸盐去除的促进或抑制机制。基于成功筛选氢自养还原菌构建连续搅拌式MBfR，通过考察硝酸盐对溴酸盐、高氯酸盐及中间产物转化规律和去除效率的影响，建立生物膜反应动力学和氢气利用定量关系，定量剖析硝酸盐、溴酸盐和高氯酸盐被微生物利用时的竞争抑制与氢气竞争抢夺机制；结合关键还原酶活性和分子生物学研究，阐明微生物种群结构和演替规律及其与污染物去除之间的关系，从多个层面揭示硝酸盐影响氢基质自养微生物去除溴酸盐和高氯酸盐的作用机制。本研究将为控制硝酸盐影响奠定理论基础，实现提高溴酸盐和高氯酸盐去除效率的目标，为进一步优化MBfR工艺提供技术支持。

水中溴酸盐和高氯酸盐因能引起潜在健康危害而被公众所关注。氢基质生物膜反应器（MBfR）作为一种新型的水处理技术，为溴酸盐和高氯酸盐的去除提供了新的思路。硝酸盐作为水中常规污染物，是MBfR去除溴酸盐和高氯酸盐的重要影响因素。如何控制硝酸盐影响是提高MBfR处理性能的关键。本项目旨在研究硝酸盐对MBfR中溴酸盐和高氯酸盐去除的促进或抑制机制。通过城市污水处理厂厌氧池活性污泥驯化培养了具有还原降解溴酸盐和高氯酸盐的自养微生物，并构建了搅拌式MBfR。在MBfR中进一步验证了溴酸盐和高氯酸盐被完全还原成低毒或无毒的溴离子和氯离子的去除机理。考察了不同浓度水平硝酸盐对溴酸盐、高氯酸盐及中间产物转化规律和去除效率的影响，建立了生物膜物质反应动力学、基质利用与生长代谢动力学和氢气利用定量关系，以定性和定量相结合的角度深度剖析了硝酸盐、溴酸盐和高氯酸盐被微生物利用时的竞争抑制与氢气竞争抢夺机制。结合关键还原酶活性和分子生物学研究，阐明了微生物种群结构和演替规律及其与污染物去除之间的关系，从多个层面揭示了硝酸盐影响氢基质自养微生物去除溴酸盐和高氯酸盐的作用机制。本研究结果为控制硝酸盐影响奠定了理论基础，实现了提高溴酸盐和高氯酸盐去除效率的目标，为进一步优化MBfR工艺提供了技术支持。