The scale of oilfield wastewater in the United States
Every oil and gas well brings up more than fuel. It also brings up produced water, salty wastewater trapped in the same rock. In 2021, wells across the United States produced about 25.9 billion barrels of it, according to a survey of state regulators by the Groundwater Protection Council. That volume has been climbing for years, up from about 21.0 billion barrels in 2007.
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| 2007 | 21.0 |
| 2012 | 21.2 |
| 2017 | 24.4 |
| 2021 | 25.9 |
Almost none of that water is reused
Almost all of that water, 95.74%, was pumped straight back underground in 2021, either to push more oil out of the ground or simply to get rid of it. Just under half went to push out more oil, and more than a third was pumped underground purely for disposal by the operators themselves. Only a small share went anywhere else, discharged, evaporated, sold or reused for something else entirely.
The last row combines discharge, evaporation, resale and reuse into one total, a figure derived by subtracting the injected share from 100%, not a single line item in the source.
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| Injected for enhanced oil recovery | 48.3 |
| Injected for disposal by operators | 37.3 |
| Injected for disposal by commercial operators | 10.1 |
| Discharged, evaporated, resold or reused | 4.3 |
What Marcellus Shale produced water could yield
The Marcellus Shale is a layer of rock under Pennsylvania and nearby states that produces natural gas, and its produced water carries lithium, the metal every electric vehicle battery needs. A study by scientists at a federal laboratory and 2 universities, published in the journal Scientific Reports in 2024, measured lithium levels of 205 milligrams per liter in produced water from northeast Pennsylvania and 127 milligrams per liter in the southwest of the state. The same study estimates that if all of that water across the state were captured, it would yield about 1,160 metric tons of lithium a year. The United States Geological Survey puts total United States lithium use at 3,000 metric tons a year, so researchers say Marcellus Shale produced water could meet 38 to 40% of that demand on its own.
A commercial plant already running on that same water
A company called Gradiant has already built a plant that pulls lithium out of that same kind of water. The plant sits in the Marcellus Shale in Pennsylvania and is on track to reach full commercial operation in early 2026. Gradiant reports a 97% lithium recovery rate in early trials and 99.5% purity for the battery grade lithium carbonate it produces, the refined lithium compound battery makers buy. The plant is under contract to supply up to 5,000 metric tons a year of that lithium carbonate to a United States lithium ion battery manufacturer. Anurag Bajpayee, chief executive of Gradiant, said this in the plant launch announcement.
We now have a fully operational lithium production asset in the U.S. that proves what EC² can deliver.
Anurag Bajpayee, chief executive of Gradiant. Source 3.
Why this water used to be a disposal problem
The bottleneck was never that this lithium was absent. It was that produced water used to be treated only as something to get rid of. A traditional evaporation pond, a shallow pool where the sun evaporates water to leave concentrated salts behind, takes 1 to 2 years to yield lithium from brine, according to the National Energy Technology Laboratory, a federal laboratory that patented a faster method in 2022. That method injects carbon dioxide into brine so the lithium forms solid minerals almost instantly, at normal temperature and pressure, instead of waiting for the sun. The Gradiant plant does not use that exact patented process. It runs its own method, but the direction across the industry is the same. Water that wells used to just pump back underground is starting to be treated as a source of lithium instead.