富营养化,营养的过度富集，例如,氮和磷，池塘，水库和湖泊，是一个紧迫的水质问题。富营养化最臭名昭著的症状是蓝细菌的大量繁殖，导致水生生物死亡，损害生态系统，危害人类健康。被认为是最有效的抵消富营养化的方法是减少外部营养输入。然而,仅仅控制外部营养负荷不足以减轻富营养化。因此,蓝藻水华的迅速减少依赖于湖内干预，其中可能包括各种各样不同的方法。混凝/絮凝是最常用和最重要的净水单元。由于蓝细菌细胞通常带有负电荷，将凝结剂加入水中以中和蓝细菌表面的负电荷，导致它们不稳定和沉淀。大多数蓝细菌及其代谢物可以同时去除。然而,当蓝藻密度很高时，由于蓝细菌的体积较小，粘性分泌物分布在细胞外。粘稠的分泌物很容易与凝结剂形成复杂的胶体，使蓝藻难以失稳，并导致对蓝藻的混凝处理效果不理想。因此,开发了各种凝固剂和凝固方法。在本文中,重点是将蓝藻的凝结作为管理富营养化的有前途的工具。基本原则,应用程序,化学的利弊，物理和生物凝血进行了综述。此外,讨论了混凝技术在水处理中的应用。本文旨在为蓝藻水华的大规模治理提供重要参考。实践要点：絮凝是控制蓝藻水华的有前途的工具。阐述了4种絮凝方法的基本原理。絮凝剂在絮凝过程中占有重要地位。
Eutrophication, the over-enrichment with nutrients, for example, nitrogen and phosphorus, of ponds, reservoirs and lakes, is an urgent water quality issue. The most notorious symptom of eutrophication is a massive proliferation of cyanobacteria, which cause aquatic organism death, impair ecosystem and harm human health. The method considered to be most effective to counteract eutrophication is to reduce external nutrient inputs. However, merely controlling external nutrient load is insufficient to mitigate eutrophication. Consequently, a rapid diminishing of cyanobacterial blooms is relied on in-lake intervention, which may encompass a great variety of different approaches. Coagulation/flocculation is the most used and important water purification unit. Since cyanobacterial cells generally carry negative charges, coagulants are added to water to neutralize the negative charges on the surface of cyanobacteria, causing them to destabilize and precipitate. Most of cyanobacteria and their metabolites can be removed simultaneously. However, when cyanobacterial density is high, sticky secretions distribute outside cells because of the small size of cyanobacteria. The sticky secretions are easily to form complex colloids with coagulants, making it difficult for cyanobacteria to destabilize and resulting in unsatisfactory treatment effects of coagulation on cyanobacteria. Therefore, various coagulants and coagulation methods were developed. In this paper, the focus is on the coagulation of cyanobacteria as a promising tool to manage eutrophication. Basic principles, applications, pros and cons of chemical, physical and biological coagulation are reviewed. In addition, the application of coagulation in water treatment is discussed. It is the aim of this
review article to provide a significant reference for large-scale governance of cyanobacterial blooms. PRACTITIONER POINTS: Flocculation was a promising tool for controlling cyanobacteria blooms. Basic principles of four kinds of flocculation methods were elucidated. Flocculant was important in the flocculation process.
