基于铁离子还原溶出作用的人工湿地污水处理效能强化研究

The clogging and decreasing of phosphorus removal could shorten the operation life of constructed wetland.It would lose the advantage in low cost if the constructed wetland only could service very short time.The clogging is closely related with the structure of constructed wetland and phosphorus removal mechanism.Changing the strcture and phosphorus removal way would avoid the clogging. The chemical phosphorus removal by using the iron ions has high the efficiency.The organic acide could extract a lot of iron ions from the substrate containing rich iron oxide in anaerobic environment because of the hydrolysis and acidfication of organic in wastewater.Based the mechanism,this study prestents the idea of chemical phosphorus removal by using the iron ions from substrate in constrcuted wetland,insteading of phosphorus removal by substrate adsorption.Furthermore, the zonal constructed wetland would be built to enhance the efficiency of wastewate treatment. And the organic,anmmonia,nitrate and phosphorus in wastewater could be removed in different sections in the new constructed wetland. In this study,for building the section of iron ions extraction,safe substrate containing rich iron oxide would screened firstly.The kinetics of iron ions extracted from the substrate was researched.To get the optimal reaction conditions,the factors influencing the reaction between the iron ions and phosphorus would be studied.The construction of the phosphorus removal section made up of the substrate would be researched based these optimal conditions.In this section, the reaction of phosphorus removal will happen and the product of reaction will be filted from wastewater.For the effective oxidation of the organic and ammonia,the construction of the oxidation section meeting the fully ampilication of wetland root also would discussed.In addition, the construction of the denitrification section employing the porus substrate will be sonsidered.At last, the technical plan of the zonal constructed wetland employing the chemical posphorus removal by iron ions would be presented based above the studies.

基质堵塞和磷去除率下降导致的使用寿命过短，正在使人工湿地技术经济性优势丧失。基质堵塞与人工湿地构造方法及吸附除磷机理密切相关，磷去除方式及人工湿地构造方法的改变可有效缓解堵塞发生。铁离子化学除磷具有高效的磷去除率，而人工湿地富氧化铁基质在有机物厌氧酸化条件下，可溶出大量的铁离子，基于这一作用，本研究提出利用铁离子化学除磷替代基质吸附除磷的技术思路，在此基础上构建有机物、氨氮、硝酸盐氮及磷分区式处理的人工湿地系统，强化污水处理效能。 项目通过筛选安全高效的富氧化铁基质并研究其中铁离子溶出动力学，构建可稳定溶出铁离子的铁溶出区，通过溶出液铁离子与磷酸盐化学反应影响因素研究，确定高效除磷反应的条件，在此基础上研究构建可实现铁离子除磷反应及形成颗粒过滤分离的基质区，然后研究构建植物根系充分发育的有机物及氨氮根系氧化区和使用大孔隙填料的反硝化区，最终提出基于铁离子化学除磷的分区式人工湿地技术方案。

人工湿地基质中铁的还原溶出以及再氧化沉积等过程能够与污水有机物、氮、磷等污染物去除相耦合。课题研究目的是通过调控人工湿地基质中铁的迁移转化过程来提升和改善人工湿地污水处理效能，特别是污水中氮和磷的去除效率。基于此目的，课题主要研究了富铁基质优选及其中铁氧化物还原溶出性能、亚铁氧化反硝化菌的富集与分离以及基于该过程的同步脱氮除磷特性、亚铁氧化反硝化脱氮颗粒产物的重金属吸附去除特性、水培湿地植物根系系统对污水中有机物、氨氮氧化能力等内容。获得了如下研究结果：优选出赤红壤和砖红壤2种铁还原和溶出性能优异的富铁基质，并富集了不同有机物作用下富铁基质中铁快速还原的4类混合菌群；获得了富铁基质亚铁溶出浓度与污水有机负荷的线性相关关系；富集了高效亚铁氧化反硝化菌群并分离了3株高效菌株；提出了基于亚铁氧化反硝化脱氮除磷的铁磷比与磷去除率的关系，以及基于亚铁氧化反硝化的脱氮除磷副产物：铁氧化物-细胞复合颗粒物作为重金属吸附剂再利用的思路；阐明了水培系统处理污水的特点及适用方式；提出了两种基于铁迁移转化的分区式人工湿地设计思路。上述研究成果进一步阐明了富铁基质人工湿地中铁的迁移转化特点，并给出了基于铁迁移转化提升人工湿地污水处理效能的具体路径和措施，对于提高和改善污水处理人工湿地处理效率具有重要的参考意义。