自1978年以来，马里斯维尔市一直依靠低技术筛选和游离氯 消毒，从3.24-mgd向客户提供优质饮用水 Stillaguamish River Ranney收集地下水资源。波动浊度力 当浊度超过1.0 NTU时，该市将关闭水源，这通常会导致 由秋季、冬季和春季的潮湿天气条件导致，但在任何时候都可能发生 时间2000年3月，华盛顿卫生部将该来源重新归类为 受地表水影响的地下水。面对地表水处理规则（SWTR），该市 选择安装过滤以使该来源符合要求。 该市初步评估了八种过滤技术，以应对各种监管要求， 运营和成本标准。在这些技术中，膜过滤似乎是最有效的 最符合该来源的标准，因为它提供了有效的治疗 适应不同的生产，符合未来的法规，废品流 成本相对较低，且占地面积小，运行维护成本最低 操作员注意力不足。 选择了膜过滤后，该市比较了压力驱动的微滤（MF） 膜和超滤膜（UF）浸没在6个月内 试点研究。初步研究表明，这两种膜都能产生优异的过滤效果 该水源的水质和性能优于预期。一般来说 UF膜净回收率略高，UF过滤器运行恢复正常 随着原水浊度峰值的延长，超滤膜所需的时间减少 化学清洗和所需的危险性较小的清洗化学品，以及UF 预计年度运维成本较低。该市选择了超滤膜 用于全尺寸设计。 因为膜被有效地包装在膜槽中，剩余的 设备通常位于膜柜附近，只有一个相对较小的区域 建筑是必需的。整个工厂可以安置在一个1.3英亩的小场地上，提供 大量节省物业购置成本。该市还通过以下方式实现了设计节约: 与UF供应商签订采购前协议，提供所有相关信息 膜设备，包括膜槽、泵、流量计、化工设备 给料设备，以及设备的所有编程。剩下的时间 设计包括在建筑物中定位设备，设计连接管道， 现场/土建设计，以及其他辅助设施或流程的设计。包括数字。

Since 1978, the City of Marysville has relied upon low-tech screening and free chlorine disinfection to supply customers with high-quality drinking water from the 3.24-mgd Stillaguamish River Ranney Collector groundwater source. Fluctuating turbidity forces the City to shut down the source when turbidity exceeds 1.0 NTU, which frequently results from wet weather conditions in the fall, winter and spring, but can occur at any time. In March 2000, the Washington Department of Health reclassified this source as groundwater under the influence of surface water. Faced with the Surface Water Treatment Rule (SWTR), the City elected to install filtration to bring this source into compliance. The City preliminarily evaluated eight filtration technologies against various regulatory, operational, and cost criteria. Of those technologies, membrane filtration appeared to best meet the criteria for this source because it provides effective treatment, it accommodates variable production, it meets future regulations, the reject flow is relatively low, and the capital and O&M costs are minimized by the small footprint and low level of operator attention required. Having selected membrane filtration, the City compared a microfiltration (MF) pressure-driven membrane and an ultrafiltration (UF) submerged membrane during a 6-month pilot study. The pilot study revealed that both membranes produced exceptional filtered water quality and performed better than expected in treatment of this source. In general, the UF membrane net recovery proved slightly higher, the UF filter run recovered and was lengthened following a raw water turbidity spike, the UF membrane required fewer chemical cleanings and required less hazardous cleaning chemicals, and the UF membrane projected annual O&M costs were lower. The City selected the UF membrane for full-scale design. Because the membranes are packed efficiently in the membrane tank and the remaining equipment is typically located adjacent to the membrane tanks, only a relatively small building is required. The entire plant can be housed on a small, 1.3-acre site, providing substantial savings in property acquisition costs. The City also realized design savings by entering into a pre-purchase agreement with the UF supplier to provide all associated membrane equipment, including the membrane tanks, pumps, flow meters, chemical feeding equipment, and all programming for their equipment. The remainder of the design consists of locating the equipment in a building, designing the connecting piping, site/civil design, and designing other ancillary facilities or processes. Includes figures.