光照对混合藻-污泥城市污水处理系统功能微生物和碳氮磷去除的影响及其应用研究

In recent years a shift, aimed at nutrient recovery and feedstock sources for biofuel production from municipal wastewaters rather than using a simple biological pollutant removal, has been implemented as an alternative approach to bioresource management. Thus, increasing attention has been paid to the indigenous microalgae-activated sludge consortium system for nutrient and energy recovery from wastewater. However, effects of light, as the energy source for autotrophic microorganisms, on their growth performance, mutual interactions, as well as nutrient uptake and removal of the microalgal-bacterial consortium have not been systematically investigated. In this project, the response of wastewater-born microalgae and activated sludge bacteria to light in the batch will be first studied to determine the optimal light condition for metabolic activities and nutrient uptake. The changes in cell pigments or metabolic rates for nutrients will be tested to elaborate the light inhibition mechanism, and accordingly, the potential strategies for activity recovery will also be proposed. Moreover, the microalgae-activated sludge consortium will be cultivated in a photobioreactor using the optimal light condition proposed above. A long-term continuous operation will be conducted to monitor and reveal microbial diversities, functional microorganisms and their metabolic pathways for carbon, nitrogen and phosphorus removals. This project will offer evidence to support the achievement of high-efficiency, low-cost municipal wastewater treatment for both nutrient and energy recovery.

在提倡生物法回收利用污水中碳氮磷而非传统去除方式的需要，以及期待从中获得生物质能原料的驱动下，混合藻-污泥耦合系统成为了污水资源化和能源化处理技术的研究热点。但是，作为光合生物的能量来源，光照条件对藻菌生长特性，耦合系统中二者相互作用以及对碳氮磷吸收去除性能的影响机制尚不清楚。本项目以基于城市污水培养的混合藻和活性污泥菌群为研究对象，分别探索混合藻和菌群在生理特征和氮磷去除等方面对不同光照条件的响应特性，确定合适的光照条件范围和光承受阈值；结合细胞色素或代谢速率分析，阐明藻菌光抑制反应机理及活性恢复的光调控策略；构建合理光照条件下混和藻-污泥耦合城市污水处理系统，探讨其长期运行下微生物群落变化情况和碳氮磷代谢通路，揭示发挥主要作用的优势和功能微生物，解释碳氮磷协同吸收去除机理，为实现高效低能耗城市污水资源化与能源化技术的应用提供依据。

藻菌共生有望同步实现污水的低碳处理和资源化，符合污水可持续处理理念，成为当前研究热点。光照作为重要因素之一，直接影响藻菌的生理活性和脱氮性能。对此，本项目以城市污水和污泥发酵液为污水水质，以微藻和活性污泥菌群为对象，分别探索了微藻和菌群在生理特征和氮磷去除等方面对不同光照条件的响应特性，主要包括三个方面的研究内容：针对微藻-城市污水系统，探索了光照强度和镁离子对城市污水-微藻生长、光合生理特征、胞内组分和胞外聚合物的影响作用，解析了上述影响因素对微藻污水氮磷去除性能和去除途径的影响机制，并从胞外聚合物、pH及DLVO理论等角度分析了光强强化微藻的综合自絮凝机理。同时，开发了绿色、可持续循环利用的微藻采收纤维素絮凝剂。其次，围绕微藻-污泥发酵液系统，探索了污泥发酵液高氨氮生境下微藻真正胁迫因子识别研究，发现游离氨（非氨氮或pH）与微藻生物量存在良好的指数关系，解析了初始游离氨 浓度及其动态变化对小球藻生理学特性影响机理及其抗胁迫调控机制。同时研究了光照条件、有机物投加和培养方式对微藻污泥发酵液系统处理性能和生物细胞组分的影响，提出了同步生物量生长和油脂生产的调控策略。第三，针对活性污泥-城市污水系统，通过光照批式实验和光照硝化动力学模型解析了光照对于氨氧化细菌和亚硝氧化菌的生理特性和脱氮途径的影响机制，进而分别构建主流和旁侧光照序批式生物反应器，利用光照调控诱导强化amoA功能基因表达，而抑制nxrB，并富集新型氨氧化菌种，稳定实现短程脱氮。这一发现为利用光照在城市低氨氮废水中建立主流短程硝化提供了一种新的途径。 项目主持人以第一/通讯作者在Chemical Engineering Journal, Applied Energy, Bioresource Technology, Science of the Total Environmental, Algal Research等环境和微藻能源期刊发表SCI论文11篇，受理专利3项，培养博士研究生3名，硕士研究生3名。