"For a number of years the stacking of phosphogypsum in Central Florida has been of great concern to me. The potential environmental disaster created when Mulberry Corporation abandoned the phosphogypsum stacks at Piney Point Phosphates in Manatee County has shown that we must give greater attention to this important issue. As the leading authority in developing alternative uses for phosphogypsum, the Florida Institute of Phosphate Research has been a valuable resource to me and my staff in attempting to find a solution to this problem. FIPR has identified many uses such as in agriculture, road construction and waste disposal in which phosphogypsum could be used in an environmentally safe and economically beneficial manner and has provided sound science to back them up."

Congressman Adam Putnam
U.S. House of Representatives
On: Utilization of phosphogypsum

Phosphogypsum is a by-product of phosphoric acid production. Like natural gypsum, phosphogypsum is calcium sulfate, a relatively innocuous compound that is used to make things like wallboard. Unlike natural gypsum, however, the phosphogypsum is slightly radioactive because of the radium associated with phosphate rock.

One of the Florida Institute of Phosphate Research's founding mandates was to study environmentally safe and economically feasible ways to use phosphogypsum. While the research has demonstrated many uses, phosphogypsum is currently stored in stacks and is banned from use by the US Environmental Protection Agency (EPA) because it is slightly radioactive.

FIPR continues its research and seeks exemptions for specific uses because the research indicates it would be more environmentally sound to use the byproduct than stack it.

There are more than 1 billion tons of phosphogypsum stored in 25 Florida stacks and 30 million new tons are produced each year. Ponds on top and at the foot of phosphogypsum stacks hold the acidic process water used to pump the phosphogypsum to the top of the stack. The water is then recycled for use in an operating plant, but becomes a liability if a plant is abandoned or closed before a stack is drained and closed.

A case in point is Mulberry Corporation, which declared bankruptcy in 2001 and abandoned three phosphogypsum stacks with full cooling ponds that the state Department of Environmental Protection is trying to drain and close. The effort is expected to ultimately cost about $160 million. Heavy rains have threatened spills from the ponds and resulted in emergency action to disperse the water. Some of the treated water has been dumped into Bishops Harbor and has caused an algae bloom in the prized estuary. Other water has been dumped into the Gulf of Mexico in accordance with an emergency EPA permit.

Current FIPR research is evaluating the use of phosphogypsum as a daily cover in landfills and monitoring roads built with phosphogypsum before it was banned from use. Recent research also looked at using phosphogypsum to build marine substrate, and to make glass tiles. Past research demonstrates its value as an economic sulfur and calcium source in agriculture and shows the radiation associated with it would not impact the crops, livestock or consumer.

• Phosphogypsum in Landfills
  

  Using phosphogypsum as a daily cover for landfills could extend the life of existing landfills, which are under increased demand each year. In Florida, about 19.5 million tons of MSW were produced in 1991, and by 2010 the yearly production of MSW is expected to increase to 30 million tons. About half of this waste ends up in landfills and the demand for landfill space continues to grow.

  This is the demonstration phase of a series of projects investigating the use of phosphogypsum in municipal solid waste (MSW) landfills to speed bacterial decomposition and extend the landfills' life.

  Phase I of this research showed that phosphogypsum will speed decomposition of simulated waste. This phase is working with real MSW and is showing that decomposition is accelerated. The study will produce a practical procedure for phosphogypsum use in a landfill operation.

  As of winter 2003 this project is on hold, as the Institute waits for EPA to grant an exemption to do the research in an actual landfill.

• Phosphogypsum Road Monitoring
  

  One of the most promising ways to use phosphogypsum is as a roadbase that is cheaper and as effective as, if not more so than, traditional roadbase materials. Past FIPR research also shows the roads do not significantly impact the environment and they actually get stronger with age.

  The most recent projects connected to phosphogypsum use in road building are a series conducted in conjunction with a FIPR application for an EPA exemption to use phosphogypsum to build a road on land where a Polk County deed restriction prohibits future home-building.

  Recent road research showed there is no significant radiation risk to those building, driving on, or living by a phosphogypsum road built on deed-restricted land. The deed restriction is to protect against the EPA risk scenario that led to the ban of phosphogypsum use. That scenario assumes that 100 years from now someone tears up the road, builds a house there, and stays in the house 18 hours a day for 70 years.

  EPA has accepted FIPR's recent risk analysis of using phosphogypsum to build roads on deed-restricted land, but now the Florida DEP wants an approved monitoring plan in place for such a road. FIPR is working with DEP on such a plan and is also retesting the two phosphogypsum roads built before the EPA ban on usage to see if there have been any long-term environmental impacts.