根据最近的健康影响数据，砷的MCL可能在不久的将来从50微克/升降至2-10微克/升；许多水源水中的砷含量接近5微克/升。一项全面的比较研究正在进行中，以确定砷处理方案；在其他过程中，正在研究膜。本文研究了几种含有总浓度约为20至50 ug/L的砷的地表水源。对于这些水源，通过使用各种实验室规模的过滤器（10、1、0.45和0.1 um）和超滤器（30000、10000、3000、1000和500道尔顿）进行粒度分级，对砷进行了表征。 通过几个不同的纳滤（NF）模块（螺旋缠绕）、一个超滤（UF）模块（螺旋缠绕和中空纤维）和一个微滤（MF）模块跟踪这些不同形式As的去除。作者还报告了不同水源水中砷的粒度分布，以及观察到的不同类型膜的截留率。还研究了亚砷酸盐在NF之前的预氧化为亚砷酸盐，作为地下水来源的一种处理方案，其中亚砷酸盐可能是砷的主要形式。

Based on recent health effects data, the MCL for arsenic (As) may be lowered from 50 to 2-10 ug/L in the near future; many source waters contain arsenic at levels near 5 ug/L. A comprehensive, comparative study is underway to define arsenic treatment options; among other processes, membranes are being investigated. This paper looks at several surface water sources which contain As spiked at a total concentration of approximately 20 to 50 ug/L. For these sources, arsenic has been characterized through size fractionation using various bench-scale filters (10, 1, 0.45, and 0.1 um) and ultrafilters (30,000, 10,000, 3,000, 1,000 and 500 daltons). Removals of these various As forms are being tracked through each of several different nanofiltration (NF) modules (spiral wound), one ultrafiltration (UF) module (spiral wound and hollow fiber), and one microfiltration (MF) module. The authors also report on As size distributions in the various source waters and rejections observed for the various types of membranes. Also studied is the preoxidation of arsenite to arsenate prior to NF as a treatment option for groundwater sources where arsenite may be the predominant form of As.