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Note: Information is from vendor, however specifications may have changed. Contact vendor for updates. Water Treatment Catalog and Decision Tool



### U V L I G H T

Process Description UV light exists in a region between visible light and x

rays, occupying a spatial spectrum between 1 to 400
nanometers (1 nm = 10

- 9 meters). In the shale gas industry, ultraviolet (UV) light has recently been

introduced as a treatment option to help reduce the volume of biocide required to kill or inhibit microbe growth in produced water that is intended for injection or

re

- use. The use of UV treatment typically takes place prior to adding chemicals to the water, such as biocides or friction reducers, since the presence of constituents in the

water can alter the effectivene ss of the treatment process.

Although the use of biocides is still necessary when UV

treatment is used on make

- up waters for microbe treatment, the volume of biocides needed are greatly

reduced. This in turn reduces residual biocides in produced water a nd thus the degree of treatment such wastewater might require. The use of UV light has been shown to reduce bacteria comparable to the efficiency of biocides in a cost effective manner and the equipment used is usually small (footprint) and can be integra ted with most production operations. Furthermore, with the application of UV light

, there is no formation of disinfection byproduct.

Technical Capabilities UV light can be used to disinfect produced water and keep bacteria viruses, fungi, algae, and protozoa from reproducing. The use of UV light is not affected by pH, temperature, or total inorganic carbon.

The effectiveness of UV light on water treatment is dependent on the rate of fluid flow, intensity of the UV light source, and the transmittance level of the fluid (e.g., the ability to allow light to completely pass through). To

achieve a level of effect iveness and success, the water needs to be irradiated at an intensity of 110 mW/m 2 with 254 nm light for one second and a transmittance rate of at least 50% at 80 barrels per minute (bpm).

Recent application of UV light in the Haynesville Shale to

treat HV HF fluids for horizontal wells indicated water treatment rates reached up to 120 bpm with disinfection quality equal to or better than the use of biocides. Volumes in the range of 3.4 to 3.7 million gallons of water were treated at an average rate of 80 bpm and initial concentrations of bacteria (1

- 10 million per cubic centimeter) were reduced by 99%. With the use of UV light, applied biocides to the water were reduced from 5,000 gallons to 500 gallons for a 5

- million gallon HVHF

stimulation.

Technical Limitations As stated, biocides are still required at reduced volumes for long

- term protection from bacteria when used in conjunction with UV light treatment. UV light treatment has no residual kill capacity and as such, the effectiveness

of the treatment is limited to waters which can be passed through the treatment system. Microbes or other organisms already present in the target formation are not Treatment Company
UV Light Shale Gas Basin Marcellus Barnett Haynesville Fayetteville Woodford

Ecosphere √ √ √

Halliburton √ KEY CONSIDERATIONS

 Can disinfect produced water and keep bacteria viruses, fungi, algae, and protozoa from reproducing.

 UV system is capable of reducing the volume of biocides from 5,000 gallons to 500 gallons for 5

- million gallon HVHF stimulation.

 Ecosphere estimates costs to treat water with their advanced oxidation process ranges from $0.60 to $0.75 per barrel (bbl).

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Note: Information is from vendor, however specifications may have changed. Contact vendor for updates. Water Treatment Catalog and Decision Tool affected by the UV water treatment process, nor are those that may be present in the additives or propants.

The performance of UV light water treatment on microbes in raw water is affected by the concentration of microbes, suspended solids, TDS (500 ppm) soluble molecules, humic acids and mineral

concentrations. P retreatment would be required to filter

out thes e constituent types.

Because constituents in the make

- up water may absorb the UV, decreasing its effectiveness at killing bacteria, the practice of reuse/recycling of produced water in subsequent fracture jobs may be incompatible with the process unless t he TDS, etc., are at low enough concentrations that adsorption does not preclude

sufficient transmittance for effective treatment.

Costs EPA estimated the capital cost for a UV system at a 1.5

- MGD plant is $200,000 which translates into $0.13/gpd. Operation and maintenance cost associated with this system is estimated at 1.5 cents/1,000 gallons of water

treated.

Ecosphere Technologies (Ecosphere) has applied UV water treatment as part of an advanced oxidation water treatment process in the Fayettev ille Shale. A ccording to Ecosphere, associated costs to treat water with their advanced oxidation process ranges from $0.60 to $0.75 per barrel (bbl); the technology is capable of processing up to 10 bpm.

References Lindsey Gloe and Greg Neal, “UV Light Reduces the Amount of Biocide Required to Disinfect Water for Fracturing Fluids,” presented at the Society of Petroleum Engineers (SPE) Eastern Regional Meeting, Charleston, WV, September 23

- 25, 2009.

Kembe Kleinwolterink, Brandon Watson, Dave Allison,

an d Matt Sharrock, “UV Light Technology Controls Bacteria while Reducing Environmental Risks,” World Oil (December 2009). Venture Engineering & Construction. Marcellus Shale. Water Treatment Options Worth Considering. Technical

Brief.

J. B. Clark, J. C. Luppens, and P. T. Tucker, “Using Ultraviolet Radiation for Controlling Sulfate

- Reducing Bacteria in Injection Water,” SPE 13245, presented at the SPE Annual Technical Conference and Exhibition, Houston, TX, September 16

- 19, 1984.

Kembe Kleinwolterink, Br andon Watson, Dave Allison, and Matt Sharrock, “UV Light Technology Controls Bacteria while Reducing Environmental Risks,” World Oil (December 2009).

Personal communication with Dennis McGuire (Ecosphere Energy Solutions, Inc.), July 10, 2009.

Nace Inte rnational, 2005. “Selection, Application, and Evaluation of Biocides in the Oil and Gas Industry”.

NACE International Publication.

Haliburton, Kawartha, Pine Ridge District Health Unit, 2010. Using Ultraviolet Light to Treat Water.

Environmental Health F ast Facts.

David Wethe, “Halliburton Hunts New Bacteria Killer to

Protect Shale

- Gas Boom,” Bloomberg (March 29, 2010).

Colorado School of Mines. Produced Water Treatment

and Beneficial Use Information Center. Treatment Options. Enhanced distillation/ev aporation

.