A biproduct of the treatment process of wastewater produced by the gas industry is a chalky, cake-like sludge that must be disposed of in a landfill permitted to receive the material by the state Department of Environmental Protection.
Some people are concerned the sludge, which may contain naturally occurring radioactive material, or NORM, could harm the environment by leaching into groundwater aquifers.
According to Carl Kirby, a geology professor at Bucknell University, humans are exposed to natural and human-induced radiation all the time - the levels are what is important.
At right is a “filter cake” — a chalky biproduct of gas industry wastewater — that must be disposed of in a DEP-permitted landfill because it contains naturally occurring radioactive material.
During the fracking process, the water and chemicals injected into the well mix with and dissolved minerals, salts and other materials in the shale.
The flowback water, which can be as much as 10 times saltier than sea water, contains the dissolved materials, frack chemicals and radioactive material, Kirby said.
The water cannot be treated by conventional wastewater treatment facilities such as those operated by the Williamsport Sanitary Authority. Two privately owned facilities operating in Williamsport, however, have been permitted to treat the water.
TerrAqua Resources, a division of Larson Design Group, is permitted to treat the water for industry reuse.
Eureka Resources, a facility opened by a partnership of local businessmen, is permitted to treat the water and discharge it to the Williamsport Sanitary Authority. Officials with the company, which also recycles the water, said the discharge exceeds new DEP standards for discharging treated gas drilling wastewater.
During the treatment process, materials removed from the wastewater are compressed into the cake-like sludge and carted off to a landfill.
For a landfill to be able to accept the material, its solid waste permit, which is issued by the DEP, must be modified, said Michael Hnatin, staff engineer for county Resource Management Services. The permit sets parameters for how the landfill will handle the waste, Hnatin said.
"If you want to modify your permit and accept the material, you have to show how the changes will allow the acceptance of that material," he said.
The landfill's design, particularly its liner system, is supposed to allow for the handling of the sludge, Hnatin said.
Kirby said not enough is known about the radiation contained in the sludge to determine its potential health risks.
"I don't think we have enough data to draw conclusions as to the level of risk anyone faces -whether potential groundwater contamination, the workers at the well site or those who are handling the wastewater," Kirby said. "There may be a risk or there may not be at risk.
"We know the water has radioactive materials in it, but we don't have many data points," he said. "More data would allow us to assess the risk better."
The Wayne Township landfill operated by the Clinton County Solid Waste Authority is among the landfills permitted to receive that waste.
Landfill General Manager Jay Alexander said he is confident the material has such low levels of radioactivity that it will not adversely impact the environment.
The authority's decision to accept the material came only after much research was done regarding the potential environmental impacts of the material and safety concerns about landfill staff who would be handling it, Alexander said.
That research included having discussions with treatment plants involved in treating gas industry wastewater to determine the types of material they would be producing.
The authority enlisted the consulting services of a State College-area scientist who determined the material would have no significant environmental impact, Alexander said.
The material contains what "looks like very low levels of radiation as a result of condensing 15 loads of flowback water into one load of sludge," Alexander said.
The Lycoming County landfill in Brady Township does not accept the material because of concerns about its composition, particularly NORM, Hnatin said.
"Our concern is that there are some trace elements that get concentrated when it goes through the wastewater treatment process. There are some radioactive elements associated with the Marcellus Shale and we did not want to assume responsibility for those materials," Hnatin said. "In a regular municipal waste landfill, they may not stay in the landfill but may come out in the leachate."
Leachate is wastewater that the landfill generates. In the case of the Lycoming County Landfill, the leachate is collected in a liner and sent to the municipal wastewater treatment plant in the Borough of Montgomery.
Alexander said the Wayne Township facility has a similar setup as the Lycoming County landfill.
Much of the material is not being disposed of in Pennsylvania, Hnatin said.
"Some is being sent to Ohio and being injected into the ground," he said. "I guess the philosophy is it came from the ground and it's safe to go back in the ground far below groundwater levels."
A protective program of testing.