Twenty minutes east of the Northwest Wellfield sits the Hialeah Water Treatment Plant. With its walls built of coral rock in 1924, Hialeah was Miami’s first major water processing facility. The water drawn from the Northwest Wellfield is piped here to be cleaned along with water from another cluster of wells that pull from straight beneath the plant. As climate change worsens, this plant will matter more and more.
A few blocks from the Hialeah plant, buried beneath what’s now a maintenance yard for the county’s Metrorail trains, lies a 1.2-acre zone that the Environmental Protection Agency has ranked the second-most hazardous Superfund site in Miami-Dade. From 1966 until 1981, the land was used by Miami Drum Services Inc., a company that rinsed containers for an assortment of toxic chemicals, then disposed of the residue on-site.
County and state officials concluded in 1981 that the operations were contaminating the aquifer;the EPA later said the space was leaching arsenic, cyanide, mercury, nickel, lead, cadmium, chromium, chloroform, and oil into the groundwater. The county forced Miami Drum Services to abandon the property and spent two months removing all “visibly contaminated soils.”
Until then, water from the Biscayne Aquifer required minimal treatment: The plant would add lime to soften it and chlorine and ammonia to disinfect it, then filter out remaining particles. Once fluoride was added to help prevent tooth decay, the water would be piped to people’s taps. In 1992, in response to the risks posed by toxins from the Miami Drum Service site and others near it, the county added a new stage, running the water through “air stripping” towers designed to remove toxic contaminants.
In 2014 an EPA report warned that “flooding from more intense and frequent storms” could push toxins from Superfund sites into underground water sources like the Biscayne Aquifer.