Ammonia trickling out of a slag dump at Geneva Steel is causing the plant to exceed federal wastewater standards.
Geneva Steel used to cool its slag with ammonia-tainted water; USX followed the same practice when it operated the mill. Geneva began using clean water on the slag pile about 11/2 years ago.But the pile is so saturated with ammonia that clean water percolating through the slag becomes laden with the chemical. The water flows from the slag pile through drainage ditches to a retention pond. It is eventually released into Utah Lake; wastewater is monitored at the lake.
Wastewater standards limit ammonia discharges to a 30-day average of 212 pounds per day; on any given day, ammonia levels can't exceed 608 pounds.
Geneva exceeded the 30-day average in July, October, November, December and January, according to Fred Pehrson, manager of permits compliance and monitoring. The mill exceeded the maximum daily level in January.
The monthly averages of excess ammonia ranged from a low of 214 pounds in October to a high of 559 in January.
Geneva Steel and the Division of Water Quality both say they knew excess ammonia would come off the slag pile but underestimated how long it would take to flush out the chemical.
"We thought it would take a year and a half," Pehrson said. "We all misestimated how long it would take."
Last summer, Geneva added biological agents to the retention pond in an attempt to reduce ammonia levels. The bugs worked well until cold weather hit.
"The bugs that were treating that residual source have gone into a coma," said Mitch Haws, manager of media relations. Geneva plans to spend about $200,000 adding a new batch of ammonia-eating bugs to the retention pond when the weather warms up.
"We have estimated that by next winter the ammonia will be flushed out of the slag dump and we won't have this problem any more," said K.C. Shaw, senior environmental engineer at Geneva.
The excess ammonia has nothing to do with the mill's $8.8 million wastewater treatment plant, which began operating last spring.
"The bug plant is doing exactly what it was designed to do," Haws said. "It is doing a wonderful job."
The Division of Water Quality has not given Geneva a violation notice in connection with the excess ammonia. The division will decide within the next two weeks whether to take enforcement action against the plant or negotiate a new compliance agreement with Geneva, Pehrson said.