Environmental Engineering Reference
In-Depth Information
(a)
Fracking recipe
Example of fracturing fluid composition from a gas well in Beaver, PA
Maximum ingredient
concentration,
% by mass
Ingredient function
Chemical
Carrier/base fluid
Proppant
Acid
Gelling agent
Freshwater
Crystalline silica
Hydrochloric acid in water
Petroleum distillate blend
85.47795%
12.66106%
1.29737%
0.14437%
0.14437%
0.04811%
0.01069%
Polysaccharide blend
Methanol
Boric acid
Sodium chloride
Cross-linker
Breaker
Friction reducer
pH-adjusting agent
Scale inhibitor
0.04252%
0.01499%
Petroleum distillate, hydrotreated light
Potassium hydroxide
Ethylene glycol
Diethylene glycol
Citric acid
Glutaraldehyde
Dimethyl benzyl ammonium chloride
Methanol
Propargyl alcohol
0.01268%
0.00540%
0.00077%
0.00360%
0.00200%
0.00067%
0.00142%
0.00010%
Iron control agent
Antibacterial agent
Corrosion inhibitor
Note: Additional proprietary ingredients not listed in material safety data sheet: acid, alcohol, biocide, copoly-
mer, disinfectant, enzyme, polymer, silica, solvent, surfactant, and weak acid. Source: FracFocus.
(b)
Salty stuff
e mix of fracking fluid and groundwater known as produced
water contains wide variations in water chemistry
Shale formation
Barnett
(TX)
Haynesville
(AR, LA, TX)
Marcellus
(NY, PA, WV)
Content (mg/l)
45,000-185,000
TDS
40,000-185,000
40,000-205,000
Cl
-
Na
+
Ca
2+
Sr
2+
Mg
2+
Ba
2+
Fe
2+
/Fe
3+
25,000-105,000
25,000-110,000
20,000-105,000
10,000-45,000
10,000-47,000
15,000-55,000
3100-34,000
5000-25,000
2200-20,000
350-3000
100-3000
500-3000
200-3000
600-5200
500-3000
30-500
100-2200
50-6000
22-100
80-350
20-200
SO
2-
15-200
100-400
10-400
TDS = total dissolved solids. Source: GE Power and Water.
FIGURE 28.10
(a) Chemical composition and (b) dissolved solids. Abundant presence of common salts makes TDS much
greater than seawater. All traditional desalination methods will likely need to be updated to deal with high-
TDS water as traditional membrane technologies, as discussed extensively in the main text. (From Bomgardner,
M.M., Cleaner fracking, in
Chemical and Engineering News
, 2012.)
(e.g., barium or strontium) can create problems for these plants, and in Pennsylvania, many
plants require that fracking wastewater not exceed 1% of the average daily value received
by the plant. In addition, in May 2011, the Pennsylvania Environmental Protection Agency
(EPA) requested that the fracking luid deliveries to 15 public wastewater treatment plants
be voluntarily discontinued. In 2011, regulators created average limits on TDS (500 mg/l),
