Orthophosphorus discharges from the J.R. Simplot Co.’s fertilizer complex into the Portneuf River west of Pocatello, Idaho, have been reduced substantially since the company entered into a voluntary consent order/compliance agreement with the Idaho Department of Environmental Quality (IDEQ) in April 2008. Simplot and IDEQ agreed that orthophosphorus discharges from the Don Plant into the river would be reduced by 50 percent in 2013, 75 percent in 2015, and 94 percent in 2021.
“We are still on track to hit those targets. We have reduced phosphorus concentrations in the river by 68 percent from the 2008 baseline,” Alan Prouty, Simplot vice president of environmental and regulatory affairs, told Green Markets. Prouty credited three projects with reducing the discharges – lining a 235-acre phosphogypsum stack, installing a groundwater extraction system with about a dozen wells to contain migration of contaminants, and improving a phosphoric acid plant’s infrastructure.
Asked if cost of the cleanup project will be $50 million, as estimated when the agreement was reached, Prouty said, “We’re making a very significant investment, especially with the lining project. Generally, we don’t discuss cost.” In compliance with the agreement, Simplot continues to pay $15,000 annually to help operate several monitoring stations on the Portneuf River. Those payments are expected to conclude in 2018. The last of four $25,000 payments to ensure water quality improvements was made in 2011. “Money from the $25,000 payments was used for at least one project in which Idaho joined with the local Trout Unlimited to purchase property near Lava Hot Springs, adjacent to the Portneuf,” where grazing and stream bank problems were identified, Prouty said.
Simplot provided equipment to assist with the river’s rehabilitation and helped buy the land, which ultimately will be turned into a public fishing access. A 10-acre decant
or “surge” pond designed to capture wastewater from the gypsum stack was completed three years ago, and recently received processed water. “The pond is working well,” said Prouty. Originally estimated to cost $2.65 million, the pond is needed to isolate decant water from a cooling tower system that has been the largest source of airborne fluoride, plus contain gypsum and any runoff. Prouty said about 20 percent of the lining project has been completed, with work on its next phase planned for this summer. “We will put the liner essentially on top of the entire gypsum stack in service.” High density polyethylene is used in the liner.
Ardaman & Associates, an Orlando-based engineering consulting company with worldwide expertise and experience, has been contracted by Simplot to oversee the liner
project. “We’re using the best liner technology available to help ensure this project provides needed protection for the environment,” said Prouty. Prouty added that Simplot is very confident the Don Plant projects will be successful. He noted the third phase of the extraction wells has been installed, with 1,000 to 1,050 gallons per minute extracted.
Simplot has operated the extraction wells in accordance with a CERCLA consent decree with the U.S. Environmental Protection Agency. About 250 to 300 gallons per minute were to be extracted under the first phase, and about 600 gallons per minute under the second phase. “We are pleased with the operations of the wells. We have no plans to install any more wells. However, we constantly evaluate groundwater data. It’s possible in the future we will install an additional well or two,” said Prouty. In April 1999, IDEQ proposed to EPA that the Total Maximum Daily Load (TMDL) for phosphorus discharges into the Portneuf be 75 parts per billion or 75 micrograms per liter at a Siphon Road monitoring site.