单质硫-菱铁矿协同驱动污水深度脱氮除磷新型技术与机制

The environmental carrying capacity has become increasingly saturated in china, requiring the sewage treatment plants implementing stricter discharge standards. However, current technology for deeply removing nitrogen and phosphorus pollutants, as represented by heterotrophic denitrification filter coupled with chemical phosphorus removal process, suffers from high operating costs and sludge yield, and is difficult to balance the COD reaching standards, which becomes the limitation factor for the upgrade of sewage treatment plants. This project proposes a novel reactive filter for deeply removal of nitrate and phosphate with low-cost element sulfur and siderite as the biocarrier. The composition principle of elemental sulfur and siderite for the removal of N and P, as well as the effects brought from the change of influent criteria will be investigated to understand the optimized status of the composite system and the potential advantages compared to the existing technologies. In addition, the fate of each relevance element and the biological information in the system will be analyzed to clarify the correlated synergistic mechanism of elemental sulfur and siderite during the removal of N and P. Further, the design principle and operation strategy of the proposed sulfur-siderite based filter will be optimized through the investigation of carrier selection, optimization strategies of back-wash and carrier supplement, etc., according to the continuous consumption characteristics of the carriers. This project is expected to technologically and theoretically support the deep removal of nitrogen and phosphorous pollutants in sewage treatment plants more cost-effective, integrated and stable.

我国环境承载能力的日趋饱和，对污水处理排放标准提出了更严格的要求。氮、磷污染物的深度去除是目前污水处理厂提标的难点，原因在于现行异养反硝化滤池联合化学除磷技术存在运行成本高、污泥产量大、兼顾COD达标难等问题。本项目创新性的提出一种利用廉价单质硫和菱铁矿作为复合活性滤料驱动污水自养反硝化脱氮耦合除磷的活性滤池工艺，拟通过研究复合体系中单质硫与菱铁矿的复配原则及其受水质条件影响的运行效果，明晰其获得高效脱氮除磷效能的状态特征及相较于现有技术的潜在优势。同时，通过解析复合体系中各元素的转化归趋途径及生物学信息，阐明单质硫和菱铁矿在脱氮除磷过程中的协同机制。基于此，进一步重点结合活性滤料在脱氮除磷过程中不断消耗的特征，开展滤料优选、反冲洗及补料操作优化等研究，提出滤池优化构建方法与运行控制策略。最终为污水处理厂深度脱氮除磷工艺向运行成本低、集约度高、稳定性好的方向发展提供技术和理论支撑。

污水深度脱氮除磷是从源头控制水体富营养化的关键。传统异养反硝化滤池联合化学除磷技术存在运行成本高、污泥产量大、兼顾COD达标难等问题。本项目创新性地提出利用廉价单质硫和菱铁矿协同驱动污水深度脱氮除磷的技术思路，发现协同体系脱氮速率较单独体系分别提升3.3倍和11.3倍，揭示了硫自养反硝化和铁自养反硝化过程的产物抑制相互解除和铁循环带来的反应热区拓展效应是协同体系实现高效脱氮的关键机制；证实协同体系可实现高效同步脱氮除磷，阐明了“硫自养反硝化过程产酸→促进菱铁矿中Fe(II)释放→铁、磷多途径结合实现除磷”的过程协同机制；发明了单质硫-菱铁矿复合活性填料及以其为核心的自养型脱氮除磷滤池工艺，阐明了通过调控活性填料组分比例、填料形貌和滤池流向来实现工艺优化构建的原理，提出通过反冲洗和配合溶解性硫系化合物使用来提升工艺运行效能的优化调控策略；开展了中试及研究（120吨/天），验证了自养型脱氮除磷滤池工艺工程应用的有效性，证实运行成本较传统工艺降低40%以上。.基于项目研发的自养深度脱氮技术（SADeN®），在项目执行期间实现技术转化，在国际上率先建成日处理规模4万吨/天的自养深度脱氮滤池工程，并推广应用于浙江东阳污水处理厂（13.9万吨/天）、宜兴新概念污水处理厂（2万吨/天）等近20项工程，合计日处理水量超过40万吨。入选2022年《国家先进污染防治技术目录（水污染防治领域）》等3项国家和地方技术目录，2021年作为“污水深度生物脱氮技术与应用”项目的重要组成部分，获国家技术发明奖二等奖。