The rapid expansion of unconventional oil and gas extraction has been credited with achieving actual energy independence for the US, reducing the nation’s carbon emissions by replacing coal with natural gas to produce electricity, and boosting local economies by providing plentiful jobs. However, as in most things, the successes of fracking have a flip side. In this article, we’ll discuss the issues of handling and disposing of fracking waste.
Water, Water Everywhere; Is Any Fit to Drink?
In early 2020, oil and gas wells together produced nearly a trillion gallons annually of toxic wastewater. That may sound like an exaggeration, but most wells produce significantly more wastewater than they produce oil or gas. Handling that volume of contaminated water is overwhelming, but working with that wastewater generates even more types of waste:
- Flowback water from the well itself, including briny produced water and used fracking fluid.
- Toxic sludges and semi-solids recovered from storage tank bottoms.
- Concentrated radioactive material, known as TENORM, which occurs naturally in many sedimentary rock formations, but is artificially concentrated in the process of hydraulic fracturing and extraction.
- Material residues, including filter cake and filter socks. Filter socks capture sediment and suspended solids as wastewater is pumped into storage tanks. Filter cakes are the compacted solid material that remains. These residues contain high concentrations of radioactive elements, heavy metals and other toxic chemicals.
Radioactivity is Hot
One of the most alarming characteristics about waste from shale formations is the amount of radioactive material brought up from thousands of feet below ground, mixed with wastewater. Shale plays produce high levels of radioactive waste because the richest shale gas formations in the US derive from former ocean floors. All ocean water contains low concentrations of uranium and thorium, and organic matter naturally attracts and concentrates these radioactive elements. Over thousands of years, these ancient ocean floors were gradually covered with dead algae, plants, and aquatic animals, forming layers of organic sediment. Under intense heat and pressure, the carbon-based matter decayed into hydrocarbons, still mixed with the dissolved radioactive materials. When shale plays are fracked, these radioactive elements are released along with gas, oil, heavy metals, salts, and produced water.
In the US, where much of the continent is made up of ancient ocean beds, the richest shale deposits are located exactly where the highest uranium concentrations are. In fact, many shale gas companies are aware of the correlation and actively seek out highly radioactive formations for prospecting.
Flowback Water
Flowback water in a fracking project is a combination of chemically laden fracking fluid (slickwater) and produced water released from the shale formation itself. Since produced water is typically very salty, it’s often referred to, rather politely, as brine. Oil and gas brine, however, contains heavy metals such as cadmium, arsenic, and lead; highly toxic compounds like benzene; and radium. The most plentiful radioactive element in these formations is the isotope radium 226.
- Radium 226 has a half-life of 1600 years, so it will continue to give off dangerous levels of radioactivity for thousands of years to come.
- Radium 226 is water soluble, which allows it to easily travel through soil and disperse into any water source.
- Radium 226 readily attaches to dust, making it easy to accidentally inhale or ingest.
- Radium 226 is bone-seeking, which means that once it’s inside the body, the isotope’s chemical similarity to calcium permits it to adhere well to bones and other hard tissues.
- Exposure to even low levels of radium 226 is known to cause bone, liver, and breast cancer.
- Radium 226 decays into radon 222, a radioactive gas which is the second leading cause of lung cancer in the US.
Considering the hazardous profile of fracking wastewater, it’s alarming to hear that a 2018 Duke University analysis determined that the volume of wastewater produced from newly fracked wells had risen by 1440% over five years, from 2011-2016. It’s important to keep in mind that drillers and fracking companies have been adjusting their drilling strategy by drilling fewer vertical wells and instead choosing to drill longer horizontal sections or even multiple horizontal arms. These changes obviously reduce the total number of wells on paper, but the fracs cover a much larger area and require substantially more water. So, an increase in wastewater per well isn’t necessarily a cause for huge alarm, but 1440% is still a disproportionate increase to the total production of those wells.
Fracking wastewater is hazardous enough that most of it is injected into and permanently sealed in extremely deep wells. If it’s not injected, the wastewater may be sent to a treatment facility for handling. In either case, it must be transported to its destination via highway or pipeline. Wastewater must also be stored at the drilling site and at its destination until it’s treated or injected. At each stage, whether it’s movement, transfer, or stationary storage, there is potential for accidental spills or improper handling, which present substantial risks to nearby populations and their drinking water supplies.
Recycling
As the industry’s extravagant use of water has become a flashpoint in the debate over water scarcity, many companies have turned to recycling at least a portion of their flowback water. This practice can potentially lower the total amount of water used and eventually disposed of. This is a desirable outcome, but recycled flowback water has a lot of disadvantages, which limits its adoption across the industry.
Recycled flowback water is relatively expensive. It must be treated after each use, but repeated recycling can leave impurities behind which will gradually reduce the life of some equipment as they become more and more concentrated. In regions where water scarcity isn’t already an issue, it’s often cheaper to just buy fresh water.
Treatment & Discharge
Treatment standards for fracking wastewater are inconsistent and often poorly enforced, leading to situations where treatment facilities are faced with conflicting and absent standards, or inadequate tools to deal with the specific hazards they’re handling. In this confusion, human and environmental risks are frequently disregarded.
In 2011, Pennsylvania found itself in the national spotlight because municipal sewage and industrial wastewater treatment plants across the state were found to be accepting fracking wastewater for treatment even though they were incapable of removing certain contaminants. After “treatment” this water, which still contained corrosive salts, heavy metals, and isotopes of radium, was discharged directly into nearby surface waters, including the river that supplies Pittsburgh’s drinking water.
Despite years of litigation, bad publicity, contaminated water supplies, and community outrage, the small Pennsylvania town of Dimock is now (2022) preparing to accept fracking wastewater for treatment in a new facility. Operators of the facility intend to sell some of the water for reuse in agriculture as well as fracking operations, but some will be discharged into Burdick Creek, a small stream that meanders through residents’ yards and farms, eventually flowing into the Susquehanna River. Water from this creek supplies drinking water for cattle as well as water for showers and laundry for downstream residents.
The treatment plant also plans to distill and crystallize certain minerals during treatment for resale. The town of Eureka PA, for example, sells salts recovered from fracking waste for use in swimming pools.
One of the most obvious concerns here is that absence of regulation does not indicate absence of risk. Swimming pool chlorine, whatever the provenance, does not have to be tested for radioactivity. In 2018, a specialized “state of the art” fracking-waste treatment facility in West Virginia regularly vented emissions from treatment tanks into the atmosphere. The emissions were first passed through a scrubber to remove hazardous pollutants, but the scrubber can’t remove radon. When a state Department of Environmental Protection official was questioned, he explained that radionuclides were not a regulated pollutant under applicable statues. “This does not mean that radionuclides are prohibited; they are simply not regulated.”
An ideal solution to the quandary of water usage and abundant waste stream would be to successfully treat the water until it’s safe to return to the environment and then manage the (substantially smaller amount of) remaining solid waste in a reliable, safe manner. However, with an industry that is moving faster than slow-moving regulators can keep up with, situations like the ones faced by residents in Pennsylvania leave everyone unprotected and ignorant of the risks they may be facing even from the air they breathe in.
