Rehab work should keep Brady passive treatment system functional for 20-25 years
Rehabilitation work should keep a system that uses nature to clean acid mine drainage functional for 20 to 25 years, said Tim Danehy of the Slippery Rock Watershed Coalition.
“It's the most economically effective way to treat mine drainage,” he said.
The Jennings Passive Treatment System in Brady cost $125,000 to build in 1997, said Eric Best, state environmental education specialist, and it outlasted its expected 10-year design life, ceasing operation in 2012.
It was revamped this year at a cost of $90,000, funded by the coalition through state and federal grants and private funds.
Passive treatment systems take advantage of naturally occurring chemical and biological processes to treat acid mine drainage and do not require constant chemical input or monitoring.
The passive system consists of a vertical flow pond, where gravity pulls acid mine drainage through a mixture of crushed limestone and mushroom compost, Best said. This raises the pH level and neutralizes the acid in the mine water.
The drainage is then exposed to oxygen and a chemical reaction forces metals from the solution, which is captured in a wetland below the pond.
The vertical flow pond was drained, and the old crushed limestone and mushroom compost was dug out and replaced, said Miranda Crotsley, Jennings program coordinator.
Also, the pipes that bring the mine water into the treatment pond were replaced and reconfigured in the rehabilitation process.
Danehy said the passive treatment system has restored Big Run Stream, which was polluted for many years. Jennings has become a state park used to conduct research and develop passive mine treatment systems.
Seals on an inactive mine failed in the 1980s, sending acid drainage into Big Run, a tributary to Slippery Rock Creek, creating a zone with little or no vegetation.
The Jennings system requires relatively little maintenance, only quarterly checks, Danehy said.
There are 20 passive treatment systems on the Slippery Rock Creek watershed, Crotsley said.
“It's a widespread attempt at treating (mine drainage),” he said. “It's probably our largest pollution problem, and this system is making quite a difference on the Slippery Rock Creek watershed.”
The Jennings Environmental Education Center, in partnership with the Slippery Rock Watershed Coalition and Stream Restoration Inc., celebrated the rehabilitation of the system with an open house and tour of the system on Monday.
Rachel Farkas is a staff writer for Trib Total Media. She can be reached at 724-779-6902 or firstname.lastname@example.org.