应用程序的最大操作障碍 低压膜过滤的缺点是污染，即:。， 通量的减少或跨膜的增加 运行期间的压力（TMP），因为 膜内物质的积累 膜表面的孔或孔。污垢 一旦达到“临界渗透通量”，渗透通量迅速增加 被超越了。然而，没有标准的协议存在 用于测量临界通量或TMP，作为 凝结或改变水质。这样的协议， 它可以提供类似于 通过在常规水中进行罐式测试而获得 治疗是必要的。本文介绍了benchscale 可用于测量临界值的技术 通量，并确定改变水的影响 质量取决于膜的性能。台秤 测试还用于证明该方法的有效性 混凝对低压锅炉性能的影响 膜系统。 临界通量的概念描述了最大 无需快速污染即可使用的渗透通量 膜的表面。描述了临界通量 在理论上，但测试程序 本文依赖于一个可操作的定义 临界通量:存在的最高通量 随着过滤时间的延长，TMP只有很小的线性增加。 在本文介绍的实验中，通量 大于临界通量会导致指数增长 用过滤体积增加TMP，并标记 “超级关键。”临界通量的测量值 随着过滤时间的增加而减少（每个 进行临界流量测试）。经验公式 是为了预测 过滤时间更长。 作者提出，类似的建议- 规模临界 公用事业公司和顾问应使用流量测量 协助设计低压膜 系统，以在 改变水质，并确定 凝固或其他处理对性能的影响 膜低压系统。作者也 建议自来水公司和咨询公司考虑 采用低压泵台架试验程序 过滤器，建议对结果进行评估 使用平均TMP与通量的曲线图 不同的时间步和结果外推到 更长的时间步长。这将提供一个相对保守的方案 临界通量的估算。包括43个参考文献、表格和图表。

The biggest operational obstacle to the application of low-pressure membrane filtration is fouling, i.e., the reduction of flux or the increase in transmembrane pressure (TMP) during operation because of the accumulation of materials within the membrane pores or on the surface of the membrane. Fouling increases rapidly once a "critical permeate flux" has been exceeded. However, no standard protocols exist for measuring critical flux or TMP as a function of coagulation or changing water quality. Such a protocol, which could provide information analogous to that provided by jar testing in conventional water treatment, is necessary. This article describes benchscale techniques that can be used to measure critical flux and determine the effects of changing water quality on membrane performance. The bench-scale test is also used to demonstrate the effectiveness of coagulation on the performance of low-pressure membrane systems. The concept of critical flux describes the maximum permeate flux that can be applied without rapid fouling of the membrane. Critical flux has been described in a theoretical fashion, but the testing procedure proposed in this article relies on an operational definition of critical flux: the highest flux for which there was only a small linear increase in TMP with time of filtration. In the experiments presented in this article, fluxes greater than the critical flux resulted in exponentially increasing TMP with filtered volume and were labeled "super-critical." The measured value for critical flux decreased with increasing time of filtration (for each step in the critical flux test). An empirical equation was developed to allow prediction of critical flux for longer filtration times. The authors propose that similar bench-scale critical flux measurements should be used by utilities and consultants to assist in the design of low-pressure membrane systems, to modify operation during periods of changing water quality, and to determine the effects of coagulation or other treatments on performance of low-pressure membrane systems. The authors also propose that water utilities and consultants consider adopting bench-scale testing procedures for low-pressure filters, and it is recommended that results are evaluated using plots of average TMP versus flux, with different time steps and with extrapolation of results to longer time steps. This would provide a relatively conservative estimate of critical flux. Includes 43 references, table, figures.