COMMERCE - Thursday, a team of engineers from the University of Oklahoma provided a tour of the passive treatment system for contaminated mine drainage now under construction near Commerce.
“This is the first mine water treatment facility of any kind in this district,” said Dr. Robert Nairn, associate professor at OU's school of civil engineering and environmental science. “This project involves design, construction and evaluation of a passive treatment system for contaminated mine drainage.”
According to Nairn, the traditional “active” treatment system typically involves chemical mixing and aeration requiring around the clock operation and maintenance.
“Passive systems are low maintenance and provide the proper environment for naturally occurring biogeochemical, biological and physical processes to positively impact water quality,” Nairn said.
The Mayer Ranch Passive Treatment Center, located behind Carpet Mill Outlet at the edge of Commerce, is a 10-cell treatment system designed to treat contaminated water left from undermining in the Tar Creek Superfund Site.
Beginning in the early 1900s and continuing to some degree as late as the 1970s the site was extensively mined for lead and zinc. The mining left miles of underground tunnels, open mine shafts and drill holes.
After the mines were abandoned, they filled with water. Groundwater moves slowly through the mines reacting with heavy metals.
Where the resulting mine drainage emerges on the surface, elevated levels of metals, especially iron, zinc, lead and cadmium, threaten both water quality and ecosystems, according to B.T. Thomas, consultant for CH2Mhill, the contractors building the treatment system.
“Despite some local belief, the high levels of metal found in the water is not a result of mining companies abandoning equipment,” Thomas said “The contamination is a result of high levels of ground metals such as iron pyrite - or fool's gold.”
According to Nairn, the current water contaminant produces approximately 200,000 pounds of iron, 14,000 pounds of zinc, 11 pounds of cadmium and 23 pounds of lead each year.
The passive treatment system is designed to remediate mine drainage with the construction of passive treatment systems.
The contaminated water will rise to the surface in an oxidation pond, where it will remain for a period of eight days before moving to surface flow wetlands. From the wetlands it will pass through vertical flow bioreactors, then to another oxidation pond. After passing through the second oxidation pond, the water will pass through limestone beds and into a polishing wetland before it empties into a channel locally known as Tar Creek.
The site also includes a storm-water diversion swale.
The vertical flow bioreactors will be made up of limestone and organic material produced locally.
“The limestone, in rock formation, will come from a local source,” Nairn said. “The organic material will be made up of a mixture of fine limestone, wood chippings from area storms and mushroom compost from J&M Farms.”
The metal deposits that will remain in the oxidation pond after the water has filtrated will be used to produce a number of products.
“I know a man who painted his van with metal sludge,” said Thomas.
“It has also been used as tile flooring,” Nairn said.
According to Thomas, it will take approximately 25 years for the oxidation ponds to build up with sludge.
“The process should begin working in about a month,” Nairn said.
The project is one of many phases funded under the Oklahoma Plan for Tar Creek.