Iron be gone. Manganese, away. A $14.2 million groundwater treatment facility that scrubs iron and manganese from supplies at a wellfield in El Rio has switched on. The plant will improve drinking supplies for thousands of Ventura County residents, including families living at Naval Base Ventura County. On Wednesday morning, officials and dignitaries celebrated the United Water Conservation District project at its El Rio facility at 3561 N. Rose Ave., north of Oxnard. … Wednesday’s gathering marked completion of the plant’s first phase after construction started around February 2022. The facility treats supplies pumped from deep wells. The first phase will treat up to 3,500 gallons of groundwater per minute. Future phases can expand capacity to about 8,250 gallons per minute.