School of Environmental Science and Engineering, Shandong University, Jinan, 250100, China.
School of Environmental Science and Engineering, Shandong University, Jinan, 250100, China; Shandong Provincial Engineering Centre for Environmental Science and Technology, Jinan, 250061, China.
Water Res. 2018 Oct 15;143:550-560. doi: 10.1016/j.watres.2018.07.015. Epub 2018 Jul 7.
Removing harmful cyanobacteria intact by coagulation can prevent cell lysis and toxin release, which provides many benefits for drinking water production, including reduction of the burden on subsequent processes and guaranteeing the water quality. But the electronegativity and buoyancy of cyanobacterial cells make them settle slowly and their accumulation and concentration in flocs would still have severe adverse effects. In this study, we introduced a photocatalyst powder to act as a ballasting agent in the coagulation process and to degrade the cells and cyanotoxins during sludge storage. Results showed that adding N-TiO would decrease the coagulant dose to half of the conventional value, and also allow Microcystis aeruginosa cells to completely settle within 10 min. During sludge storage, the algal cells, cyanotoxins and other organics in sludge would be degraded to safe levels after 32 h' visible-light irradiation. Meanwhile, the N-TiO, water and some of the coagulant in purified sludge will be directly and safely reused. Thus, this is an environmentally friendly and cost-effective technology which incorporates photocatalyst in algal flocs to enhance coagulation and sedimentation and to enable the sludge produced to be self-purified under visible-light.
通过混凝作用完整地去除有害蓝藻，可以防止细胞裂解和毒素释放，这为饮用水生产带来了许多好处，包括减轻后续处理的负担和保证水质。但是，蓝藻细胞的电负性和浮力使其沉降缓慢，并且在絮体中的积累和浓缩仍会产生严重的不利影响。在这项研究中，我们引入了一种光催化剂粉末，作为混凝过程中的加重剂，并在污泥储存期间降解细胞和蓝藻毒素。结果表明，添加 N-TiO2 可将混凝剂的用量减少到常规值的一半，并且还可以使铜绿微囊藻细胞在 10 分钟内完全沉降。在污泥储存期间，经过 32 小时可见光照射后，污泥中的藻类细胞、蓝藻毒素和其他有机物将被降解到安全水平。同时，经过净化的污泥中的 N-TiO2、水和部分混凝剂可直接安全地重复使用。因此，这是一种环保且具有成本效益的技术，它将光催化剂纳入藻絮凝体中，以增强混凝和沉降，并使产生的污泥在可见光下实现自净化。
