A tote of Frack water was delivered by Oil/Gas Remediation Center personnel in Utah to Colorado Springs on January 15, 2015. According to the centers personnel the water was mainly produced water mixed with some late stage flowback water from gas production wells. The water had been pretreated to remove oil using a gun barrel oil separation system. A series of treatability tests were conducted at the IPA Automation facility in Colorado Springs. The treatability tests were run with a variety of power and flowrate settings using the 10 gpm test unit equipped with iron plates. Remediation Center personnel had six of the samples tested at a third party laboratory and supplied the results to F&T.
Treatment goals included the reduction of these contaminants:
The best overall treatment was the treatment conducted at the lower flowrate setting (2.5 gpm) and the higher power setting (200 A). See the attached result spreadsheet for results, removal efficiencies and pictures of the samples.
The initial TSS concentration in the raw water was 184 mg/L TSS. The TSS of the treated samples ranged from 1 mg/L – 7 mg/L representing a removal range of 96-99%.
Testing was conducted for both the total iron and the ferrous form of iron on all of the samples. The concentration of the total and ferrous iron concentrations in the raw sample were 4.8 mg/L and 3.9 mg/L respectively. The results for both of these iron tests were not detectable in all of the treated samples that were tested. Even though iron plates were used as sacrificial electrodes, all of the dissolved iron was removed from the solution in the flocullated material.
The boron concentration in the raw sample was 18.3 mg/L. The boron concentrations in the treated samples ranged from 15mg/L-16.4 mg/L representing removal rates of 10%-18%. The best treatment was conducted at the lower flowrate of 2.5 gpm and at an ampearge of 200 Amps which, as mentioned above, yielded the best overall treatment results with a boron removal rate of 18%. Boron removal rates in this range are typically of what can be expected from treatment by electrocoagulation.
The electrocoagulation treatment of the Armada water showed very good removal rates for the dissolved levels of barium, magnesium and strontium metals. All three of these parameters showed excellent removal rates with the best overall treatment yielding results of 3.1 mg/L dissolved barium (92% removal), non detectable concentration for Magnesium (99+% removal) and non detectable concentration for Strontium (99+% removal).
The concentration of dissolved calcium in the raw water sample was 163 mg/L. The concentration of dissolved calcium in the sample with the best overall tretament was 5.6 mg/L which represents a removal rate of 97%. The calcium levels are important as high Calcium levels are indicative of high water hardness levels. The water hardness on all of the samples was also measured. The raw water had a harness level of 459 (mg/L as CaCO3). The hardness measurements on the treated samples were all significantly lower than the raw sample with the best overall treatment having a hardness level of 13.9 (mg/L as CaC)O3 representing a 97% reduction in hardness.
The concentration of the organic components including BTEX were not measured.
The treatment results were generally very good. Most of the parameters of interest showed excellent reductions for the water treated by electrocoagulation. A series of treatment protocols were carried out at 2 different flowrates – 2.5 gpm and 5 gpm. At the same power settings the results for the lower flowrate were markedly improved over the samples taken at the higher flowrate. A similar relationship exists with the various power settings that were utilized during the testing- the higher the Amperage used, the better the treatment efficiencies were.
The Best Overall Treatment Test Showed the Following Reductions:
Calcium – 97%
Magnesium – 99+%
Barium – 92%
Strontium – 76%
Total Iron – 99+%
Iron (Ferrous) – 99+%
Total Hardness – 97%
Total Suspended Solids (TSS) – 97%
The laboratory data also reported the Langalier Saturation Index (LSI), which is an indicator of the scaling potential of the water. The laboratory data indicates that the LSI of the treated samples are all positive and the water is prone to scaling. This is somewhat puzzling as the calcium concentrations, a major component in the calculated LSI result, are reduced substantially in the treated samples, with the best treatment having a calcium reduction of 97%.
Overall, the electrocoagulation treatment of the Remediation Centers water was very successful.
|Sample Description:||FT-002 011515||FT-004 011515||FT-006 011515||FT-008 011515||FT-010 011515||FT-012 011515||FT-014 011515|
|Flow Rate through EC||2.5 gpm||2.5 gpm||2.5 gpm||5 gpm||5 gpm||5 gpm|
|Power supplu||100A||% Removal||150A||% Removal||200A||% Removal||100A||% Removal||150A||% Removal||200A||% Removal|
|P Alkalinity (mg/L as CaCO3)||0||0||90||200||0||0||0|
|M Alkalinity (mg/L as CaCO3)||1110||820||740||690||980||920||900|
|Chloride (mg/L as Cl-)||7,296||7,299||7,322||7,405||7,446||7,385||7,474|
|Sulfate (mg/L as SO42-)||ND||0.2||0.2||0.1||ND||0.1||0.2|
|Arsenic (mg/L as As5+)||ND||ND||N/A||ND||N/A||ND||N/A||ND||N/A||ND||N/A||ND||N/A|
|Sodium (mg/L as Na+)||4,975||4,767||4||4,630||7||4,472||10||4,483||10||4,349||13||4,347||13|
|Potassium (mg/L as K+)||39||38.7||1||37.1||5||37||5||35.7||8||35.4||9||35.8||8|
|Calcium (mg/L as Ca2+)||163||40.4||75||12||93||5.6||97||119||27||88.9||45||50||69|
|Magnesium (mg/L as Mg2+)||12.4||10.3||17||ND||>99||ND||>99||10.2||18||10.2||18||ND||>99|
|Barium (mg/L as Ba2+)||39.3||21.1||46||7.2||82||3.1||92||28.1||28||25.1||36||23.3||41|
|Strontium (mg/L as Sr2+)||32.6||22.7||30||10.6||67||7.7||76||28.4||13||25.9||21||23.8||27|
|Iron, Ferrous (mg/L as Fe2+)||3.9||ND||>99||ND||>99||ND||>99||ND||>99||ND||>99||ND||>99|
|Iron, Total (mg/L as Fe)||4.8||ND||>99||ND||>99||ND||>99||ND||>99||ND||>99||ND||>99|
|Boron (mg/L as B3+)||18.3||16.4||10||15.4||16||15||18||16.1||12||15.3||16||15||18|
|Calculated Osmotic Strength (mOsm/Kg)||453||434||425||415||429||418||421|
|Calc. Total Hardness (mg/L as CaCO3)||459||143||69||29.9||93||13.9||97||338||26||264||42||125||73|
|Total Suspended Solids (mg/L)||184||7||96||3||98||6||97||1||99||3||98||1||99|
|Calc. TDS (mg/L)||13,917||13,217||5||12,825||8||12,539||10||13,365||4||13,057||7||13,067||6|
|Langelier Saturation Index (LSI)||1.19||1.38||1.54||1.94||1.37||1.27||1.37|