本研究的目的是确定两种过滤装置的相对效率，即膜过滤器和公称孔径（NPS）过滤器。至少在两个实验室进行了使用膜滤筒的加标样品研究，尽管国家颗粒去除调查（未出版）中使用了膜装置，但未从NPS过滤器中采集和分析比较样品。结果来自于并排运行的NPS过滤器和康宁1.0 um改性QR聚碳酸酯膜盒。在尤蒂卡水处理厂的原水取水口和流入为处理厂供水的水库的溪流中采集样本。 数据显示，本研究中使用的膜盒（Corning Cryptest）使隐孢子虫卵囊的回收率提高了五倍，贾第虫囊肿的回收率提高了两倍。

The objective of this study was to determine the relative efficiency of two types of filtration devices, membrane filters and Nominal Pore Size (NPS) filters. Spiked sample studies using a membrane filter cartridge have been carried out in at least two laboratories, and although a membrane device was used in the National Particle Removal Survey (unpublished), comparative samples were not taken and analyzed from NPS filters. Results are from NPS filters and Corning 1.0 um modified QR polycarbonate membrane cartridges that were operated side by side. Samples were collected at the raw water intake to Utica's Water Treatment plant and from the streams flowing into the reservoir supplying the treatment plant. The data shows that the membrane cartridges used in this study (Corning Cryptest) increased the recovery rate by five times for Cryptosporidium oocysts and two times for Giardia cysts.