在纽约锡拉丘兹地区的七个地点，对全尺寸市政慢砂过滤器在刮滤前、刮滤期间和刮滤后进行了监测，以验证是否存在成熟期，确定过滤器运行长度，并量化刮滤和再砂作业所需的劳动力和材料。结果显示，在监测的10次手术中，有4次有成熟期，从6小时到2周不等。成熟期的存在与否似乎与预氯化的使用、水温、刮削方法或过滤器维护的频率无关。 对滤液质量影响最大的因素似乎是原水中颗粒物的数量和性质。包括18个参考文献、表格、图表。

Full-scale municipal slow sand filters at seven sites in the Syracuse, New York, area were monitored before, during, and after filter scraping to verify the presence or absence of a ripening period, to determine the filter run length, and to quantify the labor and material required for scraping and resanding operations. Results showed some evidence of a ripening period, ranging from 6 hours to 2 weeks, in four of the 10 operations monitored. The presence or absence of a ripening period did not seem to be related to the use of prechlorination, to water temperature, to scraping methodology, or to frequency of filter maintenance. The factor that seemed to have the most significant effect on the quality of the filtrate was the amount and nature of the particulate matter present in the raw water. Includes 18 references, tables, figures.