南加州大都会水区评估了一个大直径、超低压反渗透（RO）元件，以降低与大型脱盐设施相关的资本成本。16英寸。（直径）x 60英寸。（长度）RO元件与标准的商用8-in并联运行。40英寸。RO元素，以比较渗透通量和盐截留率的差异。进行了经济评估，以确定与大直径反渗透元件相关的潜在成本节约。而两种反渗透元素表现出相似的盐截留率（大于98）。 5%），16英寸的比通量。直径元素比8英寸小20%。直径元素。这种流量差异可能是由于第一代原型的设计或制造效率低下造成的，并且可能不代表商业元件的性能。初步成本估算表明，反渗透系统资本成本（不包括盐水成本）可减少约24%，主要通过列车管道和容器支架减少80%。使用大型元件可能还有许多其他好处，包括减少密封件的数量（常见故障源）、更小的占地面积和减少维护要求。 包括8个参考文献、表格、图表。

The Metropolitan Water District of Southern California evaluated alarge-diameter, ultra-low- pressure reverse osmosis (RO) element in an effort tolower the capital cost associated with large-scale desalting facilities. A 16-in.(diameter) x 60-in. (length) RO element was operated in parallel with a standard,commercially available 8-in. x 40-in. RO element to compare differences inpermeate flux and salt rejection. An economic evaluation was conducted todetermine the potential cost savings associated with large-diameter RO elements.While both RO elements exhibited similar salt rejection (greater than 98.5percent), the specific flux of the 16-in. diameter element was 20 percent lessthan the 8-in. diameter element. This flux difference may have resulted fromdesign or manufacturing inefficiencies of this first- generation prototype andmay not be indicative of commercial element performance. Preliminary costestimates indicate that an approximately 24 percent reduction in RO systemcapital costs (excluding brine costs) can be achieved mainly through an 80percent reduction in train piping and vessel support frames. The use of largeelements may have many other benefits, including a reduced number of seals(common sources of failures), a smaller footprint, and reduced maintenancerequirements. Includes 8 references, tables, figures.