The natural gas industry has responded quickly to a report we did last week on a new study looking at the potential harm from fracking wastewater treatment and removal.
Krohn wrote a lengthy critique of Stony Brook University's report that can be read here.
Here are some of the issues we discussed during our phone interview:
On risk to drinking water supplies
The study finds the highest risk of ground and drinking water becoming contaminated from fracking wastewater occurs during the disposal process (versus transportation, drilling, or storage).
After elevated levels of bromide were found downstream from wastewater plants treating fracking wastewater in Pennsylvania in 2011, the state banned the practice.
But Krohn says the elevated bromide levels were never linked to fracking and more likely came from low water levels and acid mine runoff.
"In that time period you have a lot of water tests that have been done [...] and none of those water testing results have ever indicated throughout the history of the modern development of the Marcellus Shale that there have been impacts in surface water or ground water resources of the types that have been alleged by this Stony Brook study," Krohn said.
On amount of water that is recycled
Fracking a natural gas well requires well over a million gallons of water. Since development of the Marcellus Shale began about eight years ago, the amount of water that is reused in other wells has increased. But Krohn and study co-author Dan Rozell are at odds on just how many times that water can be recycled.
"As the industry continues to operate and refine its operations, it becomes more efficient and its footprint is smaller than what it was previously," said Krohn.
Study co-author Rozell conceded the data used for his study was captured through the summer of 2011.
Rozell says that due to how contaminated fracking flowback is, it can usually only be recycled once. But Krohn contends that number is more like 20 times.
"Can I say with absolute certainly that everybody in the natural gas industry is reaching that number? No, I can't," Krohn said. "But I can tell you that one time is not reflective of the current operation procedure that we're seeing throughout the Marcellus Shale."
About 70 percent of fracking wastewater in neighboring Pennsylvania is recycled before being sent - usually - to deep well injection sites in Ohio for disposal, according to Krohn.
On those deep well injection sites
Flowback water from fracking contains high levels of salt and radioactive materials absorbed deep in the shale formations.
One industry practice for disposing of that flowback is to send the water back down deep into the ground, far away from aquifers and drinking water supplies. But injection wells near other shale gas formations have been linked to causing minor earthquakes.
Krohn concedes no method for disposing wastewater is perfect. He also points out that none of the current available sources of energy generation are.