冲击负荷对循环水养殖系统生物滤器硝化效率影响的微观机理研究

Ammonia is toxic to aquatic animals, which is removed by the biofilter in recirculating aquaculture system (RAS). The fluctuation of hydrodynamic condition and wastewater quality rising from the aquiculture system does a negative impact on the nitrification, which is a main reason for the unsteady nitrification in the biofilter of RAS system. However, the mechanism on the impact of shock loading on the nitrification in the biofilter is unclear. In this study, the advanced microelectrodes and confocal laser scanning microscope (CLSM) technique will be combined with ammonia nitrogen analysis as well as the molecular biology techniques to reveal the nitrification efficiency, and the characteristics of the mass transport in biofilm, dynamic evolution of nitrifiers population, biofilm structure, extracellular polymeric substance, and then the analysis of the relationship between nitrification efficiency, mass transport in the biofilm, extracellular polymeric substance, microbial population dynamics will be conducted. In such a way, the mechanism on the impact of shock loading on the nitrification will be clarified, which will provide a scientific reference for the biofilter design, and also for explaining the microbial mechanism on the biofilm maintaining the structure and function in the biofilter under the oligotrophic condition.

氨氮对水产动物有毒性，在循环水养殖系统内通过生物滤器硝化作用去除。然而，养殖系统水质及水力的负荷变化对生物滤器硝化过程有冲击，是生物滤器处理效果不稳定的主要原因，然而，冲击负荷对滤器硝化作用影响的微观机理尚不明确。本研究应用先进微电极、CLSM等微观检测技术与脱氮效率分析手段，结合现代分子生物技术，从滤器生物膜微观组成结构出发，明确冲击负荷对生物滤器硝化效果影响效应，硝化效率与生物膜内部微观传质动力学过程的关系，揭示生物膜胞外多聚物组成分布结构特性和硝化功能微生物种群演变，与滤器硝化效率耐负荷冲击的联动机制，进而阐明冲击负荷下滤器微生物生态调控机制，为生物滤器工艺设计，系统阐述寡营养滤器生物膜结构与功能维持稳定的微生物学机理提供科学依据。

项目围绕循环水养殖系统中生物滤器运行效果不稳定等实际问题，探索冲击负荷对生物滤器处理养殖废水效果影响的微观机理，在生物滤器生物膜研究方面取得重要进展：（1）明确了循环水养殖工程中生物滤器生物膜EPS含量较污水处理厂活性污泥EPS含量高，EPS中蛋白质含量较多糖含量高等特征；（2）针对生物硝化持续产酸容易导致pH冲击问题，构建牡蛎壳生物滤器，并明确牡蛎壳调节生物硝化pH效果；（3）发明1套生物膜原位测试装置（ZL201510556183.X；ZL201520679243.2），实现水力负荷量化表征；（4）研究发现与突变水力冲击负荷相比，渐变水力冲击负荷大幅降低膜厚度，同时生物膜EPS量明显增加，渐变及突变水力冲击负荷均对氨氮去除产生显著影响，对去除有机物影响不明显。项目研究结果为生物滤器工艺设计，阐述寡营养状态下微生物膜的膜结构与功能维持稳定提供科学依据。