Cleaning up the water from fracturing

Pennsylvania officials are reviewing permits for up to 12 plants to treat the wastewater from natural gas drilling operations that use hydraulic fracturing:

Water is a huge factor in freeing natural gas trapped in the layer of Marcellus Shale that runs beneath much of the state. After a well is drilled, water mixed with various chemicals and sand is forced down the well to fracture the shale and release the gas.
The process is called hydraulic fracturing, or “fracking.” The tainted water that returns to the surface is called “flowback.”
Disposal of the tainted water is a relatively new and evolving industry in northern Pennsylvania.
DEP issued 1,592 Marcellus Shale gas well drilling permits in the first 10 months of 2009. More than one-third of them were in the 14-county north-central region.