生物海绵铁体系中铁与微生物协同同步反硝化作用机制及其应用基础研究

With the high-speed development of economy and the accelerating of urbanization process, nitrogen pollution of water body has become increasingly serious. The most important mission for the cultural working of environmental protection was to increase the intensity of sewage denitrification and strictly control the emissions of nitrogen. The study carried out new denitrogenation process which simplifies the operation, reduces production cost is being studied intensively. Previous studies have found that biological sponge iron system(BSIS) has strong denitrification effect in aerobic conditions, but the denitrification mechanism was unclear. In the present project, its mechanism of simultaneous denitrification under the synergistic effect of iron and microbiology will be revealed by studying the characteristics of anoxic denitrification inside biofilm attaching on the surface of sponge iron and the impact of iron on diversity of nitrifying bacteria and denitrifying bacteria using Sequencing Batch Reactor(SBR) with biological sponge iron and can provide theory foundation for developing new type denitrogenation process.The main contents of the project include：(1)The effect and affecting factors of denitrogenation in the BSIS. (2)the characteristics of anoxic denitrification in the BSIS. (3)The impact of iron on diversity of nitrifying bacteria and denitrifying bacteria in the BSIS. (4)The enrichment, separation, depuration and denitrification performance of aerobic denitrifying bacteria in the BSIS.(5)The enhancement techniques of nitrification and simultaneous aerobic denitrification in the BSIS.

随着经济高速发展及城镇化进程的不断加快，氮素造成的水体污染日趋严重，加大污水脱氮力度，严格控制氮排放，已成为环保工作面临的重要任务。开发操作简便、经济高效的实用新型脱氮工艺已成为研究的热点。前期研究发现，好氧条件下生物海绵铁体系(Biological Sponge Iron System,简称BSIS)具有良好脱氮效果，但脱氮作用机理尚不清楚。本课题拟以间歇式BSIS为对象，通过考察体系中海绵铁表面生物膜内的缺氧同步反硝化特征与体系中铁对硝化及反硝化菌群多样性影响，揭示该体系中铁与微生物协同作用下的同步反硝化作用机制，为开发新型高效脱氮工艺提供理论基础。研究内容包括: BSIS强化脱氮效果及其影响因素研究；BSIS中缺氧反硝化特征研究；BSIS中铁对硝化及反硝化菌群多样性影响研究；BSIS中好氧反硝化菌的富集、分离纯化与脱氮性能研究；BSIS中强化硝化与同步好氧反硝化技术研究。

将廉价易得的海绵铁（以Fe0为主的多孔材料）粒包裹成球状，以生物载体的形式介入到普通活性污泥SBR中形成生物海绵铁体系反应器（BSIS），明显促进了体系的同步反硝化作用，极大提高了反应器TN的去除效果。通过对球状海绵铁载体表面及内部DO分布特征研究发现，球体内存在厌氧-缺氧-好氧“微环境”；球状海绵铁填料为不同类型微生物的附着生长提供了有利环境，提高了BSIS反应器中细菌的群落丰富度，出现了与铁循环和脱氮相关的功能菌如铁氧化菌、铁还原菌、自养反硝化菌、异养反硝化菌和硝化细菌，使BSIS的脱氮效果明显高于普通SBR。在BSIS脱氮影响因素及海绵铁投加量对BSIS中微生物菌群影响研究基础上，从BSIS中分离出具有铁氧化能力的好氧反硝化菌（简称菌液），富集驯化与分离纯化后，分别投加到加铁与不加铁的SBR中，进行针对硝态氮与亚硝态氮的好氧反硝化影响因素和铁氧化能力研究，揭示了BSIS 中铁与好氧反硝化菌协同强化脱氮作用机制；进行了菌液强化BSIS反应器硝化与同步好氧反硝化能力影响因素研究。得出了海绵铁是维持菌液强化反硝化脱氮效果的主要因素；分离出的菌液对硝化的生物强化作用不大、且长期离开海绵铁后强化反硝化脱氮作用会降低；分离出的菌液对硝酸盐氮的好氧反硝化效果好于亚硝酸盐的效果；BSIS中海绵铁促进的好氧反硝化作用在反应器碳源充足情况下可以提高10%左右的TN去除率；在碳源缺乏情况下可以提高30%以上的TN去除率等主要结论。研究成果为该技术的深入研究与实用化打下了一定基础。