关键词: 微纳米曝气, 磷, 藻类, 水质改善, Micro-nano aeration, phosphorus, algae, water quality improvement

Abstract: In this study, Dongyaxi Reservoir in Sanming City, Fujian province was taken as the research object.?The effect of ecological restoration of the micro-nanometer aeration project in four seasons was evaluated??by comparing the water quality and phytoplankton characteristics in the aeration area and non-aeration area.?The effect of micro-nanometer aeration project in Niulingku Bay was evaluated in 2017. The results indicate that the dissolved oxygen in the water body bottom layer is 0.3~1.1 mg/ L higher than the dissolved oxygen in the non-aeration area due to the micro-nano aeration in the aeration area. The reduction rate of total phosphorus concentration was 14.0%~29.1%. Aeration may have an effect on promoting the reduction of total phosphorus by precipitation, adsorption, adhesion and other removal, and phosphorus is easy to be adsorbed by minerals rich in Fe,Al and Ca.?Total nitrogen concentration was not markedly?reduced,it may be that different aeration conditions affect the removal efficiency of ammonium nitrogen and nitrate nitrogen, this is also related to the background value of nitrogen in water. In addition, the reduction rate of chlorophyll and?algae cell abundance?in water was 25.1%~51.0% and 16.9%~37.9%,?respectively. In summer, the reduction of of chlorophyll and algae cells achieved?the highest, 51.0% and 37.9%, respectively. Comparison between aeration area and non-aeration area, the reduction rate of the algae cell abundance is 16.9%~37.9%, the reduction rate of the Cyanobacteria is 14%~26%, the reduction rate of the green algae is 19%~51%, and the reduction rate of the diatom is 20%~36%, which shows that the micro-nanometer aeration can inhibit the growth of the phytoplankton to a certain extent. The inhibitory effect of micro-nanometer aeration on algae growth may be due to the rapid extinction of algae caused by the inhibition of phosphorus release by microbial species of sediment and the increase of turbidity of water body. In the present study, the micro-nanometer aeration disc is placed at the bottom of the water body, and the effect of aeration on the growth of the algae is obviously inhibited due to the adsorption and fixing action of the bottom mud to the phosphorus. The results show that the micro-nanometer aeration technology can control algae well in summer. As a new aeration technology, micro-nanometer aeration is widely used in the field of environmental pollution remediation because of its low investment, no secondary pollution and convenient operation and management. Micro-nanometer aeration technology can change dissolved oxygen in water body, restore and enhance microbial activity in water body, so as to purify water quality. It is a promising technique for ecological restoration of water source, which can be further studied by combining with other ecological indicators such as zooplankton. Water eutrophication is easy to erupt in spring and summer. When the temperature begins to rise gradually, considering the cost-benefit and other factors, the micro-nanometer aeration project can operate in spring and summer in order to inhibit the growth of algae, while in autumn and winter, aeration can be properly reduced in order to achieve the optimization of benefits.