Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
Sci Total Environ. 2020 Nov 25;745:141013. doi: 10.1016/j.scitotenv.2020.141013. Epub 2020 Jul 19.
Algal blooms severely impact the ecological environment and human health, as well as drinking water supplies and treatment systems. This study investigated UV-radiation-enhanced aluminum (Al)-based coagulation for the removal of two representative algal species (Microcystis aeruginosa and Cyclotella sp.) which are responsible for most fresh water algal bloom in different seasons. The results demonstrated that the UV-Al process can enhance algae removal, and simultaneously control algal organic matter (AOM) release. Comparing with Microcystis aeruginosa, Cyclotella sp. was more sensitive to UV irradiation and its activity was severely inhibited by 240 s of UV irradiation; intracellular reactive oxygen species (ROS) increased sharply then decreased rapidly, and SEM images showed cell walls exhibited substantial compression. UV irradiation decreased the zeta potential, which might have contributed to algae removal. Approximately 93.5% of Microcystis aeruginosa cells and 91.4% of Cyclotella sp. cells were removed after 240 s of UV irradiation with 0.4 mmol/L Al. The MCs concentrations after Al coagulation were low (<100 ng/L). The DOC of Microcystis aeruginosa and Cyclotella sp. was also lower (1.2 and 1.6 mg/L, respectively) than the national standard level after UV-Al process. This study highlights the practical application of UV irradiation for enhancing algae removal and simultaneously controlling AOM release in water treatment plants, which is a simple and promising technology. This result also indicates that the water treatment parameters should be adjusted according to the algae species present in different seasons, especially for diatom which needs low UV irradiation and Al dosage.
藻华严重影响生态环境和人类健康，以及饮用水供应和处理系统。本研究调查了紫外线增强的铝（Al）基混凝去除两种代表性藻类（铜绿微囊藻和菱形藻）的效果，这两种藻类是不同季节淡水藻华的主要原因。结果表明，UV-Al 工艺可以增强藻类的去除，同时控制藻源性有机物（AOM）的释放。与铜绿微囊藻相比，菱形藻对紫外线辐射更为敏感，其活性在 240 秒的紫外线辐射下受到严重抑制；细胞内活性氧（ROS）急剧增加然后迅速减少，SEM 图像显示细胞壁受到严重压缩。紫外线辐射降低了zeta 电位，这可能有助于藻类的去除。经过 240 秒的紫外线照射和 0.4mmol/L Al 处理后，铜绿微囊藻的细胞去除率约为 93.5%，菱形藻的细胞去除率约为 91.4%。混凝沉淀后，微囊藻和菱形藻的 MCs 浓度均较低（<100ng/L）。经过 UV-Al 处理后，微囊藻和菱形藻的溶解性有机碳（DOC）也较低（分别为 1.2 和 1.6mg/L），低于国家标准水平。本研究强调了紫外线辐射在水处理厂增强藻类去除和同时控制 AOM 释放的实际应用，这是一种简单而有前途的技术。该结果还表明，应根据不同季节存在的藻类种类调整水处理参数，特别是对于需要低紫外线辐射和低 Al 剂量的硅藻。
