Proposed wastewater standards create the need for “other solutions”

BY ERIC LIDJI FOR GREENING OF OIL 

Many policy debates over Marcellus Shale development quickly become technological challenges, like proposed regulations in Pennsylvania over total dissolves solids, or TDS.

Simply put, TDS is the amount of microscopic stuff, like chemicals and minerals, in a liquid. High enough concentrations of TDS can make water undrinkable for humans, harmful to animals and worthless for industry. The Environmental Quality Board, an agency inside the Pennsylvania Department of Environmental Protection, recently finalized new TDS standards for wastewater discharge into lakes, rivers and streams: 500 milligrams per liter for natural gas development and 2,000 mg/L for other industries.

Those in favor of the measure call it a long-overdue protection of water supplies, while those opposed call it an expensive idea divorced from scientific reality. Either way, the potential regulations now before state lawmakers would make knottier a question already facing shale development: What do you do with millions of gallons of wastewater?

“That treatment standard says to developers: find some other solutions,” said Kelvin Gregory, in the Department of Civil and Environmental Engineering at Carnegie Mellon University. Gregory is one of the people trying to find other solutions. Along with two researchers at the University of Pittsburgh, he’s looking for ways to improve water use in the development of the Marcellus Shale, like using acid mine drainage instead of fresh water to fracture reservoirs, and managing the flowback water that returns to the surface.

In setting a tougher standard for natural gas development, the Environmental Quality Board said drilling involved much larger volumes of wastewater at a much higher concentration than other industries, creating unique technological challenges.

“The industry does have other disposal options available to it. What we didn’t want to do was whack existing industry,” said Tom Rathbun, a Pennsylvania DEP spokesman.

Gregory agreed: “It’s been around for 60 years,” he said about the hydraulic fracturing used to develop shale deposits. “We’ve been treating flowback water as environmental engineers for that long as well… The key is: how much does it cost to get there?” 

Something beyond thermal processing

So the challenge isn’t so much inventing technologies as improving them. There are already four ways to handle flowback water: dilute it, treat it, recycle it or dispose it. Each is imperfect, though: too costly, too risky or not practical for Pennsylvania.

For instance, flowback water gets higher concentrations of salty TDS the longer it stays underground, hitting levels between 100,000 and 200,000 mg/L, according to Gregory. Getting that down to 500 mg/L doesn’t require sophisticated technology, just a lot more water to dilute it. That solution would use hundreds of millions of gallons of fresh water every year, though. That’s a bit much, even for a water rich state like Pennsylvania.

Disposing the flowback water in deep wells is an option, but Pennsylvania doesn’t have as many of these approved disposal locations as other states rich in unconventional gas.

A common solution is “thermal processes” like crystallization, using heat to remove the solids. Heat takes energy, though, and energy is expensive. “It just boils down to economics,” said Kent Perry, managing director of unconventional gas for the Gas Technology Institute, a non-profit research and development firm in northern Illinois.

Perry said industry wants both better and cheaper technologies. “The biggest thrust is probably to develop something new beyond the thermal processes,” he said. Ideas include improvements to technologies, like electrodes that break salt into its basic components of sodium and chloride, but also ways to make money from the produced water stream, like turning it into the common salt compound sprinkled on northern roads in winter. 

Absorbing the cost, or negating it?

“The rule will present treatment costs to the oil and gas industry, which may be minimized through recycling and reuse, zero discharge treatment technologies or underground injection options,” the board wrote in its final order. “However, this industry should be very capable of absorbing these costs as minimal when compared to the expected revenues from the Pennsylvania Marcellus shale formation.”

Cheaper technologies could turn more of those revenues to profits by reducing expenses, but could also increase those revenues by making more potential drill sites economic.

Gregory and his partners see potential in mobile recycling units, where flowback water can be treated on site. That would not only reduce the risk and cost of moving wastewater by truck or by pipeline, but also improve the economics of sites far from water sources.

“That is probably going to be the technology that most developers are going to be moving towards,” Gregory said. Just because the proposed standard is statewide doesn’t mean the futures solutions will be, too. Treatment is about chemistry, and reservoir chemistry changes around the state. “It’s going to be different regionally, and maybe even locally.” 

Regulations still far from being law

Technology is central to the deliberations over wastewater regulation. The TDS issue arose after US Steel reported that high chloride levels in water drawn from Monongahela River was impacting machinery. Typically, the high rainfall in Pennsylvania took care of diluting waterways, but a few dry years changed that balance.

The Environmental Quality Board initially proposed the regulations in August and took comments through February. The Pennsylvania General Assembly is in the middle of a 30-day review of the regulations, as is the Pennsylvania Independent Regulatory Review Commission. If approved by both, the regulations would go to the Attorney General.

Links of interest

Environmental Quality Board final rulemaking on wastewater treatment requirements

The Gas Technology Institute

Dr. Kelvin Gregory

Contact Eric Lidji at ericlidji@mac.com