研究了三个小型（0.01至0.57-mgd）处理厂——一个采用常规过滤，一个采用在线过滤，一个采用硅藻土过滤——去除贾第虫囊肿的效果。将每种滤池的浊度和囊肿清除率与接种贾第虫囊肿的平行中试滤池（1 gpm）以及有无优化化学处理进行比较。囊肿去除率在40%到99%之间。设计和操作缺陷可能导致观察到的处理性能。主要缺陷包括化学处理的优化不足或较差、过滤器的开关循环（无反洗）、操作员对反洗缺乏控制，以及没有对废物进行过滤。包括25个参考文献、表格和图表。

The removal of Giardia cysts by three small (0.01 to 0.57-mgd) treatment plants--one with conventional filtration, one with in-line filtration, and one with diatomaceous earth filtration--was studied. Turbidity and cyst removals for each were compared with those of parallel pilot filters (1 gpm) seeded with Giardia cysts and with and without optimization of chemical treatment. Cyst removal efficiencies ranged from about 40 to 99 percent. Design and operating deficiencies likely contributed to the observed treatment performances. Major deficiencies included lack of or poor optimization of chemical treatment, on-off cycles of filters without backwashing, absence of operator control of backwashing, and no filtering to waste. Includes 25 references, tables, figures.