Frac Ponds: Treating Hydraulic Fracturing Wastewater for Reuse

Hydraulic fracturing, or fracking, is the process of injecting pressurized water, chemicals, and sand into the ground to extract shale oil and natural gas. While fracking has transformed energy production in the U.S., it requires a lot of water and thus creates a lot of wastewater, which must be treated and disposed of safely. In this video interview, Triplepoint’s resident expert, western regional manager Tom Daugherty, gives the lowdown on fracking wastewater and how frac ponds can be economically upgraded with MARS aeration. Read below for highlights and links to more information.

Where does fracking wastewater come from?

In order to create a pathway to release shale oil and natural gas, drillers inject a well with 2.5 to 5 million gallons of water that’s been mixed with sand and chemicals. The water that comes back out (flowback and produced water) contains salts, hydrocarbons, metals, chemicals, and naturally occurring radioactive materials. The EPA considers this wastewater potentially harmful and it needs to be handled and disposed of appropriately.

What are the challenges for this type of water?

frac pondsOne big challenge is determining exactly what’s in it. The exact composition varies, as each driller has a proprietary mix of chemicals in its fracking fluids. The naturally occurring volatile organic compounds known as BTEX (benzene, toluene, ethylbenzene, and xylene) are commonly found in petroleum products and in fracking wastewater. The EPA classifies them as contaminants due to the potential threat to surface and drinking water. Another challenge is the sheer volume of water involved, in the hundreds of millions of gallons.

Because the EPA bans the treatment of fracking wastewater at publicly owned treatment works, drillers determine their own wastewater treatment solutions.

What are the benefits of adding aeration to frac ponds?

In his article, Advanced Aeration in Hydraulic Fractured Water Impoundments, our own Tom Daugherty explains the benefits of adding dissolved oxygen to frac ponds. Aeration

  • oxidizes sulfide reducing bacteria, which mitigates hydrogen sulfide odors
  • stabilizes pH
  • helps to strip hydrocarbon gases and volatile compounds
  • oxidizes metals so they can be filtered or settled
  • prevents sludge buildup and surface matting
  • enhances evaporation

Fracs ponds at a drill site in Utah that were upgraded with MARS aerators demonstrated a significant reduction in BTEX chemicals: after fourteen days, benzene was reduced by 54 percent; toluene by 39 percent, and xylene by 52 percent.

What are the potential cost savings?

According to Sourcewater, an online marketplace for energy industry water sourcing and disposal, water management accounts for more than 50 percent of a well’s operating cost.  Treating onsite for reuse reduces piping, trucking, and water sourcing costs, at an estimated savings of over $150,000 per well.  In addition, access to water can be a limiting factor, so treating for reuse can ensure water is available to continue drilling.

What is the environmental impact of treating fracking wastewater?

frac pondsWhile fracking does undoubtedly present some environmental challenges, the negative perception may be overblown: A 2015 Duke University study determined that 250 billion gallons of water were used in fracking in the U.S. from 2005–2014, accounting for less than 1 percent of total industrial water usage nationwide.

Still, fracking is not the best use for pristine drinking water supplies, especially in regions with drought and water shortages. The less taken out of the ground, the better.

According to a scientific paper in Fuel, “A review of the issues and treatment options for wastewater from shale gas extraction by hydraulic fracturing,” partial treatment and reuse is the preferred method of water and wastewater management.

Onsite treatment for reuse not only saves money, it also demonstrates responsibility to the environment and may help improve the perception of fracking.

Benefits of MARS aeration in frac ponds

frac ponds

Triplepoint’s MARS aerators, which feature patented Double Bubble Technology™, combine the mixing capabilities of coarse bubbles with the superior oxygenation of fine bubbles in a modular, portable unit. MARS diffusers provide:

  • Robust mixing—Coarse bubbles are released at the bottom of the static tube, creating a draft that pulls water and liquefied organic matter up from the floor, thoroughly churning and circulating the entire water column to keep solids in suspension and prevent sludge accumulation.
  • Efficient aeration—Fine bubble diffusers surround the static tube maximize oxygen transfer efficiency while minimizing energy consumption.
  • Easy installation—Self-weighted and portable, MARS aerators are quickly installed from the surface with no system downtime.
  • Low maintenance—MARS have no submerged moving parts to clog or malfunction. The anti-fouling design, with self-checked diffusers and self-cleaning EPDM membranes, means maintenance is kept to a minimum.
  • Energy efficiency—MARS aerators are 30–50% more energy efficient than surface aerators, reducing energy demands and expense.

To learn more about how MARS can treat fracking wastewater for reuse, saving thousands of dollars in water sourcing and transportation costs, request a free quote.

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