The salty wastewater produced by oil wells has been an environmental topic for a long time.

When the oil industry was new in Kansas, the wastewater was simply dumped on the ground, creating "salt scars" that still mar the landscape in many parts of the state.

As the problems became apparent, drillers created disposal wells and dumped the produced water back into the oil-bearing formations from which it was drawn — or into deeper formations.

In more recent years, new problems have emerged on two fronts.

YES, EARTHQUAKES: Scientists agree that the enormous increase in seismic activity in Oklahoma has been triggered by the injection of wastewater produced by oil production back into the subsurface formations. The map shows the location of Oklahoma’s strongest earthquake ever, a 5.8 magnitude quake on Sept. 3, 2016.

First, as oil and gas production increases, so does the amount of wastewater produced, amounts big enough to cause many conservationists to wonder if it might not be better to treat that water and keep it in the usable water supply.

Second, injecting those huge amounts of water back into the earth is creating earthquakes that are growing stronger and stronger.

Tyler Powell, Oklahoma deputy secretary of environment, addressed those issues in a presentation to the recent Kansas Governor's Conference on the Future of Water in Kansas, held in Manhattan in November.

"We are beginning to look at the reality of water shortage," Powell said. "We have the advantage of some great reservoirs in Oklahoma. But we want to reduce our water usage from the equivalent of 1.25 Grand Lakes to one Lake Texoma. We realize that we can never pay for those reservoirs again. So our goal is to use no more water in 2060 that we did in 2010."

With that in mind, Powell said, there is the reality that in 2104 Oklahoma put 1,529 million barrels of water into saltwater disposal wells in Oklahoma — the equivalent of 200,000 acre-feet of water.

"And this was in the middle of a drought," he said. "Think about that. If we could clean that water efficiently and put it back into the water supply, think what a difference that would make."

On top of saving — and reusing — water, Powell said there is the side effect that injecting that water back into the earth is creating seismic activity. (See the interactive map of Kansas Earthquakes.)

"The reality is we historically had one or two small earthquakes a year before we started the major fracking plays," he said. “In 2013, we had 109. In 2014, there were 585 earthquakes of magnitude 3.0 or greater. In 2015, it was 907, and in 2016 so far, we've had 582, and we've had 133 in the last 90 days. We can't just sit and do nothing."

He said there is widespread agreement that it is not drilling that is causing the seismic activity, but rather the injection of the wastewater back into the ground.

"It has a lot to do with the depth of the well, the quantity of water going down and the location of the well in relation to a fault," he said. "But the relationship is real. So why not look at ways to make that water useful? It may be too expensive to treat it to the level of drinking water. But what if it could be used for cooling power plants? Or other industrial uses?"

Powell said the objective is to keep ideas flowing on how to best use water supplies that are available, even though — like water produced by oil wells — those supplies may not initially appear to be useful.