AWWA JAW59042

The new US Environmental Protection Agency (USEPA) maximum contaminant level for arsenic in drinking water (10 ug/L) will require many water utilities, especially small systems, to add unit operations for arsenic removal. This has created an immediate need to find cost-effective methods for removing arsenic. A recent study conducted on groundwater in rural Colorado explored using modified coagulation/filtration (MCF) as an arsenic removal technique. MCF has been designated by USEPA as a best available treatment. However, many previous tests for arsenic removal using this method have used carefully prepared solutions. The aim of this study was to determine the operating conditions and limitations of MCF for removing arsenic from real groundwater. The results from the Colorado study were then compared with the predictions obtained from earlier investigations using carefully prepared solutions. These study results add to a growing body of evidence that suggests ferric ion coagulation followed by filtration (either sand or microfiltration) can be a cost-effective method for arsenic removal. Includes 26 references, tables, figures.