Removal of Selenium from Agricultural Drainage Waters Using Emulsion Liquid

Agricultural drainage waters emanating from irrigation projects in seleniferous lands in the western United States are a major source of selenium contaminated waters. Because of selenium's known toxicity and teratogenicity to waterbirds, the discharge limits adopted by the California State Water Resources Control Board are very low (0.005 mg/L). Therefore, in order to prevent selenium poisoning, 40,000 acres of highly productive agricultural land has been removed from production and regulators are considering the removal of even more. In order to keep the land in production, a large scale, inexpensive method of removing selenium from agricultural drainage water is needed. Processes developed for selenium removal from drinking water (anion exchange and activated alumina) are too expensive for the treatment of agricultural drainage waters. Therefore, TDA Research proposes to develop an emulsion liquid membrane (ELM) process capable of extracting selenium from agricultural drainage waters containing high levels of dissolved salts and concentrating it for subsequent treatment and disposal.