What we know – and don't know – about toxic wastewater from the oil and gas industry

Cloelle Danforth

Co-authored by Steven Hamburg.

For all that we hear and think about oil and gas production, wastewater may not be at the top of our list of concerns. And yet, onshore oil and gas operations in the United States produce more than 800 billion gallons of toxic wastewater each year.  

Most oil and gas companies either dispose of this water deep underground, or recycle it for use in other wells. But a growing number of operators are now considering alternate ways to discharge or reuse this water above ground.

Before we can effectively manage this influx of wastewater in new ways, we need to have a better understanding of what’s in it.

This is why new research by Environmental Defense Fund in collaboration with Columbia University and the University of Colorado is so important. With generous support from the Alfred P. Sloan Foundation, we’re working hard to find better ways to test for the multitude of chemicals that may be in this wastewater.

We believe management of this water has become a defining challenge of modern oil and gas production.

An environmental problem, a resource – or both?

Historically, oil and gas operators injected about 93 percent of their wastewater deep underground. Hardly any of this wastewater was reintroduced into the ecosystem, which limited the need for regulators or others to thoroughly characterize the constituents of the wastewater.

But there are several reasons we should have a closer look now.

The escalating scarcity of fresh water in the West has prompted policymakers to explore other alternatives for oil and gas wastewater disposal – such as reusing it for irrigation and livestock purposes. Growing concerns over earthquakes sometimes caused by the use of deep disposal wells have also, in some cases, fueled such efforts.

By 2012, more than 30 billion gallons of wastewater from the oil and gas industry was discharged above ground, a volume likely to increase based on current disposal trends. The problem is, there are major gaps in our understanding of potential risks and impacts associated with such practices.

Adding this water into the ecosystem with a limited understanding of its chemistry is deeply concerning, and we need to stay ahead of such practices.

Why oil and gas wastewater is so complex 

The chemical make-up of this type of wastewater can change over time and across different geographies, making treating it a complicated issue that requires different solutions in different places at different times. 

Additionally, it can contain a variety of compounds and pollutants – for example hydraulic fracturing fluids used to stimulate the well, compounds used to maintain oil or gas production, or pollutants that are naturally present deep underground.

Existing methods of analyzing the chemical composition of the fluid are difficult to use because the wastewater is often extremely salty – as much as 10 times saltier than the ocean. And for some chemicals, testing methods that work effectively in these salty solutions simply don’t exist.

Without working methods, it’s difficult to detect and remove pollutants, understand their potential risks to the environment, and regulate and monitor them effectively.

Our goal: Less risk to ecosystem and health

The primary purpose of our new research project is to develop methods for analyzing organic chemicals in high-saline wastewater, and to investigate options for less energy and resource-intensive treatment systems than what exist for this type of wastewater today.

It will advance our current understanding of wastewater from oil and gas production and provide more clarity to operators, regulators and communities where alternative disposal methods may be taking place.

Ultimately, this work will help reduce potential risks to public health and the environment on which we all depend.