本文讨论的研究目标是确定如何对低浊度水进行化学预处理，以实现高效快速过滤，确定工艺变量对去除贾第鞭毛虫囊肿、浊度和细菌的影响，并确定使用替代指标来评估去除贾第鞭毛虫囊肿的处理效率是否可行。工艺变量包括化学预处理（混凝剂选择和用量）、过滤模式（常规、直接或在线）、过滤介质、水力加载速率和温度。 一个辅助目标是确定不使用混凝化学品时快速过滤的去除效率。研究结果表明，如果快速过滤工艺要对低浊度水有效，则必须进行适当的化学预处理。选择合适的助凝剂聚合物与主凝剂一起使用是最重要的，使用合适的剂量以实现高浊度降低也是最重要的。通过适当的化学预处理，浊度去除率有望超过70%，细菌去除率可达99%，贾第虫囊肿去除率可达95%。 在没有化学预处理的情况下，贾第虫囊肿、细菌和浊度的去除率预计在0%到70%之间。其他工艺变量不如化学预处理重要。通过直方图分析数据表明，浊度去除率或大肠菌群总去除率都可以作为贾第虫囊肿去除率的替代指标。包括9个参考文献、表格、图表。

The objectives of the research discussed in this paper were to determine how to chemically pretreat low turbidity water for efficient rapid rate filtration, to determine the effect of process variables on the removal of Giardia cysts, turbidity, and bacteria, and to ascertain whether use of a surrogate indicator is feasible for assessing the efficiency of treatment for removing Giardia cysts. The process variables included chemical pretreatment (coagulant selection and dosage), filtration mode (conventional, direct, or in-line), filter media, hydraulic loading rate, and temperature. An ancillary objective was to determine the removal efficiency of rapid rate filtration when coagulation chemicals are not used. Research results indicate that proper chemical pretreatment is imperative if the rapid rate filtration process is to be effective for low turbidity waters. Selection of the proper coagulant aid polymers to use with the primary coagulant is most important, as is the use of proper dosages to achieve high reductions of turbidity. With proper chemical pretreatment, removals can be expected to exceed 70 percent for turbidity, 99 percent for bacteria, and 95 percent for Giardia cysts. With no chemical pretreatment, removals of Giardia cysts, bacteria, and turbidity can be expected to be in the range of 0 to 70 percent. Other process variables were not as important as chemical pretreatment. Analysis of the data by means of histograms showed that either percent removal of turbidity or percent removal of total coliform bacteria could serve as a surrogate indicator of percent removal of Giardia cysts. Includes 9 references, tables, figures.