Case Study of Variable Electro Precipitation™ of Shale Produced Water

Background

Approximately 250 gallons of shale produced water from the hydraulic fracturing of the Piceance Basin near Debuque, Colorado was collected on May 7, 2013 and delivered to Colorado Springs, Colorado on May 8, 2013. The pH of the water measured at 7.05. Twelve different Variable Electro Precipitation™ treatments were conducted on the water with various flows, geometries, anodes/cathodes, and voltage settings.

Goals

Treatment goals included the reduction of these contaminates:

  1. Suspended Solids
  2. Barium, Iron, Strontium (divalent ions)
  3. Bacteria
  4. Scaling (calcium, magnesium, silicone)

Results

Table 1 below reflects the best treatment of the twelve different bench scale procedures used. This most successfully geometry/anode type would be used in a pilot test and/or production unit.

The best results were from run #COS-017 on May 14, 2013, and are summarized as follows:

  1. Total Suspended Solids removal 94.7%; consistent with historical data
  2. Barium, iron, strontium removal 40% to <98.9%; consistent with historic data
  3. Bacteria removal was undetermined due to issues with the Analytical Laboratory
  4. Scaling (hardness, silicone) removal 57% to <87%; consistent with historic data

TABLE 1. Variable Electro Percipitation of Colorado Shale Produced Water

TREATMENT OF COLORADO SHALE HYDRAULIC FRACTURING PRODUCED WATER TREATMENT BY VARIABLE ELECTRO PRECIPITATION™
Colorado Springs, Colorado - May 14, 2013
Beach Unit Run #144 (1.5 gpm)
Parameter Raw Treated % Removal (Unit #)
Sulfur Reducing Bacteria (CFU/mL) Not Available Not Available -----
Acid Producing Bacteria (CFU/mL) Not Available Not Available ----
Barium (mg/L) 73.2 21 71.3
Calcium (mg/L) 7120 5490 22.9
Iron (mg/L) 99.8 <20.0 >80
Magnesium (mg/L) 437 336 23.1
Silica (as SiO2, mg/L) 17 5.2 69.4
Silicon (mg/L) 23.8 4.22 82.3
Sodium 17,600 13,700 22.2
Strontium (mg/L) 866 629 27.4
Zinc 3.11 95.1 N/A
Chloride (mg/L) 41,800 36,800 12.0
Sulfate (mg/L) <50.0 <50.0 ----
Total Dissolved Solids 74,000 62,100 16.1
pH 7.57 7.09 ----

Figure 1. Colorado Produced Water; Raw and Variable Electro Precipitated™ Treated Samples


Conclusions

Treatment of the shale produced water was successful in reducing suspended solids, silicone, and divalent ions associated with scaling and plugging of shale formations. Unfortunately, testing for acid producing and sulfate reducing bacteria was requested but, was not carried out due to communication problems with the analytical laboratory. The treatment was also successful in reducing heavy metals including Arsenic and Lead. The Variable Electro Precipitation™ treatment resulted in the contaminants settling out of solution and leaving a clear more usable water.

Above, is a photograph of the raw and treated water, along with the analysis of the raw and treated water. It is recommended that an on-site pilot plant be set up to treat fresh produced water to confirm these excellent results.