Worth its weight: Water in the west

This story appears in the 2014-15 issue of Mines' research magazine, "Energy & the Earth."

 

Water and oil don’t mix. With oil and gas production and water, it’s quite the opposite.

Getting at the unconventional oil and gas reserves at the heart of America’s energy boom can take millions of gallons of water per well before the first hydrocarbons emerge.[1] One estimate puts the hydrologic demands of the 80,000 wells in 17 states drilled since 2005 at more than 250 billion gallons.[2] That’s three times the volume of Denver Water’s Dillon Reservoir.

Yet in the western United States and elsewhere, geologic “accident” has placed some of the most promising unconventional oil and gas reserves below parched landscapes.

Mines researchers are at the forefront of enhancing our still-nascent understanding of this modern story of oil and water, and more broadly in the development of new ways to boost freshwater resources in an era of rising demand and growing scarcity.

ConocoPhillips’ recent $3 million gift to establish the new Center for a Sustainable WE2ST (Water-Energy Education, Science and Technology) is the latest testament to Mines’ strengths in water.

The idea is to focus on a single formation such as the Niobrara, taking a comprehensive look at the complex technical and social interdependencies of oil and gas development and limited water resources. Professor John McCray, head of Mines’ Civil and Environmental Engineering Department, describes a wide-ranging effort, involving remote sensing and hydrological models to map out water sources and the tools of geochemistry, hydrology, microbiology and environmental engineering to develop ways to clean up the water that emerges from the depths during oil and gas operations. The work also will involve a strong social-sciences component led by Mines anthropologist Professor Jessica Rolston, McCray said, to help define ways to communicate the actual risks of unconventional energy development and get energy companies, regulators and the public on the same factual page.

“It’s a partnership with ConocoPhillips that can break new ground, and one that doesn’t exist outside of this center,” McCray said. “We want to come out and be the honest broker.”

Education is a key component of the ConocoPhillips center, said Associate Professor Terri Hogue, who is directing the new center. A big part of the budget will go to fellowships for 15 to 20 masters and PhD students, she said, in addition to 10 undergraduate fellowships each year. The center will attract top-notch talent all focusing on the nexus of water resources and energy development.

Professor Tzahi Cath is among those at Mines already at work at that confluence. Cath directs Mines’ Advanced Water Technology Center (AQWATEC), which is developing a range of water-treatment technologies. This spring, the masters students in Cath’s Environmental Engineering Pilot Lab course were studying if adding an inky slurry of activated charcoal to the city of Golden’s water treatment process might help remove the organics that have spiked in reservoirs along Colorado’s Front Range after the 2013 flood. A green garden hose snaked from a tank in the bed of the AQWATEC pickup parked on the sidewalk outside Coolbaugh Hall. It fed a bench-scale model of Golden’s water treatment plant, its upper tanks full of fluid like curdling apple cider. If it worked here, they would test the activated charcoal in a Mines pilot plant housed in the treatment facility itself and, assuming the city adopts the approach, would help with the transition to the full-scale plant.

“Usually, the city adopts our recommendations,” Cath said.

A bit downhill, in AQWATEC’s space in Mines’ General Research Laboratory, PhD student Bryan Coday was working near several hip-high plastic drums, some encrusted with salt (they’re for a project testing new ways to extract valuable potassium sulfate from the Great Salt Lake).

Others contained produced water from hydraulic fracturing operations, and Coday was working on a system to cleanse it using low-pressure osmosis and flat-sheet polymeric membranes. To the touch, the membranes felt like high-end wrapping paper, but in practice is a very sophisticated material. The system uses salt water to attract clean water from the deep-brown produced water across the membrane, which retains contaminants.

“Produced water is difficult to treat because of the hydrocarbons and complex organic compounds, plus high salinity,” Cath said. Mines environmental chemist Professor Christopher Higgins is working with Cath to identify just what chemicals from the different samples of produced water cross the membranes, and how they can improve the process to produce even drinking-quality water from produced water.

A test system had performed well enough that Coday and research assistant Mike Veres were now in the midst of building a pilot-scale system. “Harnessing the natural chemical energy of brine as the driving force for wastewater treatment has its advantages,” Cath said. “Such systems are mechanically simpler, take less energy, and are easier to clean because the grime hasn’t been rammed into filter pores as happens with high-pressure systems.”

If some combination of low-pressure filtration and microbial treatment (another AQWATEC project being tested across the lab in columns of activated carbon next to the AQWATEC aluminum boat) can economically bring produced water to the high standards of municipal wastewater treatment, the benefits are hard to miss. Water locked up two miles below could be released into streams in drought-prone regions, actually boosting the water budget. And oil and gas operations could reuse some portion of this new resource in their hydraulic fracturing operations. Coday is enthusiastic.

 “It’s a great opportunity to work on a project where industry is moving at such a quick pace on the energy side, on the water side and on the regulatory side,” he said.

Another major project has a similarly sweeping purview, but pertains to urban water use. Since 2011, Mines has teamed with Stanford University, the University of California at Berkeley and New Mexico State University on a 10-year, $40 million effort that aims to transform how cities in the arid West use and reuse water. The program, called Re-Inventing the Nation’s Urban Water Infrastructure (ReNUWIt), is the first National Science Foundation-funded Engineering Research Center to focus on water issues.

McCray, who leads the Mines effort, said a dozen Mines faculty are leading or working on some 20 ReNUWIt projects. Hogue is spearheading an effort involving several Mines colleagues to determine the potential impact of August 2013’s 257,000-acre Sierra Nevada Rim Fire on water supplies to San Francisco and surrounding counties. Cath’s team is refining a portable, commercial-scale sequence batch membrane bioreactor that has proven its mettle with the wastewater from the apartments at Mines Park – capable of producing drinking water from domestic wastewater. Mines professors Tissa Illangasekare and Kate Smits lead a project that is developing technology to allow underground aquifers to treat and store water and then re-use it rather than letting it escape downstream. They are researching the use of sensors that provide real-time feedback on system performance, so decisions can be made to improve operation efficiency. Mines Associate Professor Linda Figueroa is working with the Plum Creek Wastewater Authority south of Denver on a pilot-scale system using anaerobic wastewater treatment. The system has been in operation for 1.5 years and has reduced more than 40 percent of the influent organic matter without the expense of oxygen (unlike traditional aerobic methods) and, as a bonus, produces energy while it cleans wastewater.

As with the ConocoPhillips center, ReNUWIt involves a heavy social science component. That’s because, for all the technological capabilities on display at Mines, the biggest challenges facing smarter water systems may reside between our ears. People just don’t like the idea of drinking reclaimed water (in Singapore they call it NeWater), McCray said, even though that’s what the South Platte River really is. Collectively, such apprehensions coalesce into powerful social and political barriers.

 “They’re by far the biggest hurdles to clear if we’re going to have any change in the way we develop our infrastructure,” McCray said.