Case Study Summary of the Variable Electro Precipitation™ Treatment of Oil/Gas Exploration Produced Water

Background

Approximately 550 gallons of produced water was sampled from a Oil/Gas Exploration wellsite located in the Cherokee shale formation which lies within the Anadarko Basin. Two totes of water were collected on October 29, 2013 and susequently transported to Colorado Springs. From October 31, 2013 – November 6, 2013 a comprehensive series of Variable Electro Precipitation™ treatments were conducted on the water with various flows, geometries, anodes/cathodes, and voltage settings using a small scale EC system. The pH of the untreated water measured at 7.97.

Goals

Treatment goals included the reduction of these contaminants:

  1. Suspended Solids
  2. Total Suspended Solids (TSS)
  3. Bacteria

Results

A series of 35 different treatment protocols were conducted on the Oil/Gas Exploration, LLC produced water to determine the optimum operating conditions to maximize bacteria removal. The five best treatments in terms of bacteria reduction efficiency are outlined in Table 1 below.

Table 1 – Bacteria Results - Five Best VEP Treatments on Oil/Gas Exploration Produced Water
Sample # Sample Description ATP Bacteria (pg/mL) % bacteria reduction
115/125 Raw Water 9690.8 / 6348.6 N/A
131 Treated Water 1.2 >99.9
118 1.8 21 >99.9
123 Treated Water 77.9 99.2
137 Treated Water 54.7 99.14
152 Treated Water 55.9 99.12

Reduction of Total Suspended Solids (TSS) was also identified a being a priority although the produced water had a relatively low level of TSS when it arrived – 37 mg/L TSS. In addition to the TSS, hardness and metal removal was tested. Two samples were selected to be sent out for independent third party laboratory analysis. The results are shown in Table 2.

Total Dissolved Solids (TDS) was shown to be reduced by 5.2% & 4.4% for the 2 samples that were analyzed.

Total Suspened Solids (TSS) was reduced down to a level of <5.0 mg/L, which represents a reduction of greater than 86.5% for the 2 samples tested. The TSS was analyzed on the treated water after the solids had been allowed to settle and a subsample drawn off from the settled clear portion.

Hardness concentrations for the 2 samples analyzed were reduced by 75.9% and 61.3% respectively.

Table 2 – Sample Results for TDS, TSS, Hardness and Dissolved Metals on treated Oil/Gas Exploration Water
Parameter Sample# Sample Description Raw Sample Result (mg/L) Treated Sample Result (mg/L) % Reduction
TDS 163 Treated Water 10130 9600 5.2
173 Treated Water 10130 9680 4.4
TSS 163 Treated Water 37.0 <.0 >86.5
173 Treated Water 37.0 <5.0 >86.5
Hardness (as CaCO3) 163 Treated Water 326 78.7 75.9
173 Treated Water 326 126 61.3
Chloride 163 Treated Water 5660 7924 N/A
173 Treated Water 5660 5749 N/A
Dissolved Barium 163 Treated Water 0.743 0.207 72.1
173 Treated Water 0.743 0.305 59.0
Dissolved Boron 163 Treated Water 5.56 4.71 15.3
173 Treated Water 5.56 5.33 4.1
Dissolved Iron 163 Treated Water 21.7 <0.007 >99.9
173 Treated Water 21.7 0.036 99.8
Dissolved Sodium 163 Treated Water 3272 3371 N/A
173 Treated Water 3272 3080 5.9
Dissolved Strontium 163 Treated Water 18.8 6.86 63.5
173 Treated Water 18.8 9.07 51.8
Dissolved Zinc 163 Treated Water 0.475 0.319 32.8
173 Treated Water 0.475 0.175 63.2