附着藻类对养殖废水中有机磷的去除机理研究

Swine wastewater is an important agricultural non-point source, and it is also a key factor that causes severe environmental problems, such as eutrophication. Organic phosphorus is an important form of phosphorus in swine wastewater but it cannot be used directly by aquatic organisms. Periphyton is ubiquitous in aquatic environments, and it is one of the pollutants “managers” in the aquatic ecosystem. Benthic algae is the main primary producer of periphyton. The alkaline phosphatase produced by the benthic algae attached to the periphyton can convert the organic phosphorus into inorganic phosphorus. However, the key removal process and the removal mechanism of organic phosphorus by benthic algae remains unclear. In this project, periphyton will be collected from different concentration of constructed wetlands treating swine wastewater system. The composition and biological diversity of benthic algae will be studied to show the optimum conditions for culture the periphyton in the system. According to the biological diversity of benthic algae, the periphyton with good growth conditions is selected for further experiments in the laboratory. The conversion kinetics of organic phosphorus and alkaline phosphatase activity are studied to elucidate the key conversion process of organic phosphorus by benthic algae. Organic phosphorus removal and adsorption experiment, phosphorus fraction of the benthic algae are performed to reveal the removal process of organic phosphorus by benthic algae. The removal efficiency of organic phosphorus is analyzed under different environmental conditions, such as illumination intensity, temperature, and pH to prove the main influencing factors of removal organic phosphorus by benthic algae. Though the systemic researches, it is expected to reveal the process and mechanism of organic phosphorus removal by benthic algae. The project results can provide scientific basis and data support for the removal of organic phosphorus from wastewaters and the control of water eutrophication by non-point source pollution.

养殖废水是重要的农业面源污染源。有机磷是养殖废水中磷素主要赋存形态，很难被水生生物等直接利用，是引起水体富营养化主要污染物之一。附着藻类可通过碱性磷酸酶酶解及吸附作用有效去除有机磷，但附着藻类对有机磷去除的关键过程及机理尚不清楚。本项目拟在养殖废水生态处理系统中构建附着生物膜，观察附着藻类种类组成及生物多样性。通过室内培养实验，研究附着藻类碱性磷酸酶活性及有机磷转化动力学特征，阐明附着藻类对有机磷的转化过程；开展附着藻类对有机磷的去除和吸附实验，并用连续化学提取法定量研究吸附磷形态，解析附着藻类对有机磷的主要去除途径；研究在不同光照、温度及pH条件下有机磷的去除效率，探明附着藻类对有机磷去除的主要影响因子，最终揭示附着藻类对有机磷的去除机理。研究成果可为养殖废水中有机磷的去除及水体富营养化控制提供科学依据和基础数据支撑。

废水中磷的去除研究是当前污水处理研究的重点和热点。本项目在养殖废水生态处理系统中通过挂片培养附着生物膜，研究了附着藻类对废水中磷的去除效率及机理。附着生物膜上的藻类生物多样性组成及生物量结果显示，绿藻和硅藻是主要优势门，其中绿藻门中的鞘藻为主要优势种。有机磷代谢试验结果表明，在7天的培养时间内，有机磷浓度在从30mg/L下降到5mg/L左右。利用鞘藻处理废水中的磷试验结果显示，鞘藻在沼液中Chl-a浓度达到3.35 mg/L，总磷的去除率为91.22%，约60%的磷通过同化去除，而30%的磷通过磷酸盐沉淀去除。根据藻泥中磷含量高于其他形式的研究结果，选择利用膨润土为吸附剂并对其进行改性。结果显示，Ca-P和Al-P改性膨润土是磷溶液中主要的吸附形态，而Fe-P和O-P等的含量相对较少，而Ca10-P的含量高于其他形式的吸附态磷。系列研究结果表明，附着藻类对有机磷具有较强的降解能力，通过降解后产生的无机磷，其去除以底泥化学吸附去除为主要形式。