AWWA WQTC55039

Iron and manganese removal processes have a long history of use by the water treatment industry. These processes also have the advantage of removing naturally occurring arsenic because of the affinity of arsenic for iron. Arsenic will sorb onto the precipitated iron and be removed as the iron is removed during the filtration step. The sorption of arsenic onto iron is sensitive to a number of water quality issues and operational procedures. As would be expected, these existing plants have been designed and are operated for optimum iron and manganese removal and not arsenic removal. Operational changes can be made, however, to increase arsenic removals without sacrificing their performance for iron and manganese removal. Such changes may be adequate to bring the plant into compliance with the new arsenic regulation without a major effort or cost. Each situation will likely be different and would need to be investigated before making a full scale system change. If operational changes do not produce the needed results, more costly add-on treatments or other solutions could be necessary. Includes 15 references, tables, figures.