Mosaic has applied to dig two exploratory wells at its Riverview phosphate processing plant that inject treated wastewater far underground. The mining company would use it to get rid of water in emergencies, such as major storms and hurricanes.
State environmental regulators are evaluating whether to issue a permit for what is called an "exploratory" injection well. It would send excess water from the fertilizer production plant, located along the shore of Hillsborough Bay, about 3,500 feet down, far below the aquifer used for drinking water.
Richard Lobinske is an environmental administrator with the Florida Department of Environmental Protection. During a recent public meeting in Riverview, he said hazardous waste or toxic substances would not be allowed to be injected underground.
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"And part of what this exploratory well is is to determine where the bottom of the underground source of drinking water is at," he said, "and to determine what kind of confinement is present to protect upwelling from the injections."
Exploratory wells look at the geology under the surface, including confinement layers and the depth of underground sources of drinking water.
"It's really designed to identify the subsurface geology," Lobinske said. "How it is made up, layers of confinement, where the underground source of drinking water is, and that's really the purpose of it to just see the subsurface conditions."
Mosaic spokeswoman Jackie Barron said the well would be used only during emergencies — such as hurricanes — where they need to remove water faster than they normally can. It's already in place at a couple of their other processing plants.
"This is not a go-to. It's not like we're going to automatically put water down it, but it will be nice to have in the event we have historic storms or we run into a situation where we need to dispose of water faster," she said during the public meeting. "The water has to be treated the same as any of our outfalls right now. Right now, if we outfall (have to let water off the site), we need to meet a certain water quality standard. That does not change with pretreatment with regard to these wells."
Barron said no hazardous waste is allowed to go into the wells. Any future underground injection of wastewater would require a separate permit.
"We do not believe that there are any safety concerns," she said. Not just based on what we believe, but based on the science and technology and extensive studies. Remember, this would be one of a couple of 100 across the state. So this is not a new concept."
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Lobinske said Florida has more than 200 Class I injection wells, primarily used for water and wastewater treatment. Several of these are already located in Hillsborough County.
Others handle industrial waste, but the Mosaic plant is not projected to include that.
"Quite a few of them are associated with water and wastewater.," Lobinske said. "From the water, it's going to be the brine that's left over from the reverse osmosis water purification - or other water treatment plants, the leftover product and things like that, and/or non-usable solutions that come from a water plant."
Monitoring wells are dug within 150 feet of the exploratory wells. Lobinske said injected waste is rarely detected migrating underground.
But some environmental advocates are strongly opposed to the wells. They say most wells will leak over time, and if the groundwater becomes contaminated, it's detected too late.
And the threat to the aquifer, they say, is too great.
The state is accepting public comments on the exploratory well until Nov. 5. Comments can be sent by email to app@dep.state.fl.us.
More information on the draft permit may be obtained by contacting Richard Lobinske, DEP Underground Injection Control Program, 2600 Blair Stone Road, MS 3520, Tallahassee, Florida 32399; or by email to APP@FloridaDEP.gov.
The public comment period for this draft permit will end on Nov. 5.
