Waste water
From Wikimarcellus
Waste water or flowback water from hydro-fracturing shale gas wells generally needs to be processed in a water treatment plant before being discharged.
This water typically has high levels of total dissolved solids (TDS), chlorides, and chemicals. TDS generally consist of sodium and calcium salts.
These fluids may also contain barium, iron, oil, soap, radiation (NORM), strontium, various heavy metals and other constituents.
Waste water treatment removes toxic chemicals and salt from the water used to fracture shale as well as the naturally occurring underground water that is produced by drilling and bought up to the surface.