在处理相对清澈水的社区中，通过消除沉淀过程或絮凝过程，对传统水处理工艺进行了改进。这种改进后的系统称为直接过滤。直接过滤系统中使用的混凝剂剂量远低于传统处理系统中使用的剂量。因此，在低混凝剂剂量下，评估混凝和絮凝去除病毒的有效性，以及确定浊度在病毒和混凝剂之间相互作用中的作用非常重要。讨论了硫酸铝、阳离子聚电解质、聚合物和jar试验。包括23个参考文献、表格和图表。

In communities that are treating relatively clear water, conventional water treatment processes have been modified by eliminating either the sedimentation process or the flocculation process. This modified system is referred to as direct filtration. Coagulant dosages used in direct filtration systems are much lower than dosages used in conventional treatment systems. It is therefore important to assess the effectiveness of coagulation and flocculation for virus removal at low coagulant dosages and also to determine the role of turbidity in the interaction between virus and the coagulants. Aluminum sulfate, cationic polyelectrolytes, polymers, and jar tests are discussed. Includes 23 references, tables, figures.