The fluids that come back out of a well after it has been hydraulicallyfractured are called drilling wastewater. Wastewater is made of fluids from two distinct sources: the water that was pumped into the ground to be used to hydraulically fracture the well, and the water already present in the pores and cracks in the rocks of the target formation (the rock
layer from which gas will be extracted, in this case, the Marcellus Shale). Wastewater varies in composition
depending upon how long ago the well was fractured, and the fracturing chemicals that were used.