Lithium Removal From Drinking Water

Lithium (Li) is listed on the U.S. Environmental Protection Agency's fifth Contaminant Candidate List (CCL 5), and its occurrence in drinking water is being quantified under the fifth Unregulated Contaminant Monitoring Rule (UCMR5). Little information is available on its removal from drinking water. The current study evaluated 19 historical pilot- and full-scale studies and conducted sampling at 13 water treatment plants. The 32 sites included 3 surface water and 29 groundwater sources, and 8 treatment process categories. Conventional surface water treatment, adsorptive media, biological aerobic groundwater treatment, and manganese removal filters were not effective at removing Li. Cation exchange sometimes achieved Li removal, but removals were inconsistent. Lime softening often removed 11%–54% Li, but treated water Li typically was > 10 μg/L. RO removed > 90% of Li, although finished water concentrations depended on blending rates. This study fills a critical gap in evaluating Li treatability through the existing water treatment infrastructure.