Rain and dredged seawater help to dilute contaminated water at plant
By MATT M. JOHNSON
MANATEE -- A recent test of contaminated water stored at the former Piney Point Phosphates fertilizer manufacturing plant shows water quality generally improving as rain and dredged seawater dilutes organic chemicals, metals and radioactive compounds.
For some opponents of a state and county plan to dispose of millions of gallons of that water down a 3,500-foot well, dilution is one more reason not to pump contaminants underground. Critics, including members of the Manatee County Farm Bureau, have repeatedly raised concerns the wastewater may damage the local aquifer.
"The majority of the water in there is rainwater," said Manatee County farmer Ben King, who recently toured the hulking stacks of phosphogypsum waste that contain the water on land across the street from Port Manatee. "Why even put it in?"
The latest test data, compiled by the Florida Department of Environmental Protection in March, is from a narrow sampling of water at the site. Tests indicate levels of most contaminants in the property's primary holding pond do not exceed U.S. Environmental Protec
tion Agency drinking water standards.
But the water remains too salty and nutrient-rich to be drained into rivers, lakes or the Gulf of Mexico.
The new numbers come as DEP reviews 15 public comments concerning the proposed construction of a Class I industrial injection well at the Piney Point site. To be built by Manatee County, the well would pump about 1 million gallons a day of stored industrial waste water underground. It is the latest plan to eliminate about a half-billion gallons of wastewater left in about 400 acres of ponds by the former fertilizer plant.
If built, the well would pump the water into a portion of the aquifer deemed undrinkable due to a high salt content.
To date, DEP has spent about $142 million cleaning up the site and dealing with a 2011 holding pond leak that spilled more than 170 million gallons of contaminated water into nearby Bishop Harbor.
Manatee County would build and operate the injection well. The construction cost is estimated at $7.5 million.
Some county residents and environmental advocates have been asking DEP officials for updated testing since two public meetings in April and May. Of particular concern is the amount of radioactive contamination present in the water.
New test results show most contaminants in the stored industrial wastewater, or "process water," used in the fertilizer operation have been diluted to lower levels over time. Looking at samples taken from one water storage pond historically used for process water at the Piney Point site, DEP officials point to five contaminant trends. The DEP compared the new water samples with baselines taken in May 2002.
New trends include:
Radium, a radioactive element, tested at 1 picocuries per liter, which is below the maximum water contaminant level of 5 set by the U.S. Environmental Protection Agency.
The pH or acidity of the water has increased from a value of 2.99 to 5 from sea and rainwater. The change takes the water from an acidity level like vinegar to one in the normal range of rainwater.
Fertilizer compound ammonia nitrogen has dropped from 600 milligrams per liter to 200.
Another fertilizer compound, phosphorus, has dropped from 1,400 milligrams per liter to 420.
Chlorides, or salt, increased from 110 milligrams per liter to 1,300.
Since 2010, water sampling at the site has found few contaminant levels exceeding EPA standards. Two elements -- beryllium and cadmium -- did reach levels exceeding the standards in 2012, according to DEP. The measurements were made in water sampled from a drain structure on the property.
The newest results were met with skepticism by a longtime opponent of the phosphogypsum fertilizer industry. Glenn Compton, founder of environmental advocacy group Manasota 88, said the amount of contaminants remains constant.
"It's really not a reduction, it's a dilution," he said. "It's just being mixed in with more rainwater and seawater from dredge materials."
A higher volume of water with a lower percentage of contamination could be even more damaging to the aquifer, Compton said. High water volume could spread the contamination faster and farther, even into the freshwater aquifer hundreds of feet above the bottom of the well.
King, who toured some of the storage ponds at the Piney Point site two weeks ago with other Farm Bureau members and county officials, said he is now more convinced the water should stay where it is. The ponds have become homes for fish and birds. Water levels are well below the tops of the stack ponds, which he said should alleviate fears the containment could breach again as in 2011.
For their part, Manatee County officials say achieving neutral pH levels is important if the well project begins operating. They have stated in public meetings one of the biggest threats to the phosphogypsum stacks is a rainy summer that could cause the ponds to fail.
Amy Pilson, spokeswoman for the county's utilities department, said the county will learn in November whether the state plans to issue a permit for the injection well.
Matt M. Johnson, Herald business reporter, can be reached at 941-745-7027, or on Twitter @MattAtBradenton.