Environmental Engineering Reference
In-Depth Information
(b)
Add
· Fracking chemicals
· Proppants (sand)
Water loop
—well operators have many
choices for wastewater reuse or disposal (red).
Freshwater source
Fracturing fluid
Gas well
Transport
Flowback and
produced water
Transport
Disposal well
Municipal water
treatment plant
Reuse
Analysis and treatment
· Chemical treatment
· Filters
Release
More treatment
· Desalination
· Evaporation
· Crystallization
Sludge by-product
to disposal site
Shutterstock/C&EN
Zero-liquid discharge
FIGURE 28.9 (Continued)
(b) Typical HF cycle of water. Initially, water, proppants, and fracking chemicals are injected into the well until
high enough pressures to fracture the rock bed occur. Some of the water returns (~20%-40%) to the surface,
while the rest remains in the well. Of the lowback water, reuse for further fracturing or treatment, either
at a municipal water treatment plant or zero-liquid discharge facility or disposed of by deep well injection,
are the pathways for managing the waste stream. (From Bomgardner, M.M., Cleaner fracking, in
Chemical and
Engineering News
, 2012.)
