You know how fracking is so controversial, because applying high pressure to deep formations might cause hydrocarbons to migrate upwards and contaminate shallow drinking water aquifers? Texas has got the next best thing. This article calls it “fracking for uranium” which is just plain wrong. Fracking relies on high pressure to break apart rocks holding oil and gas. Uranium harvesting relies upon geochemistry to leach uranium out of rocks – no high pressure needed – and it has relatively low water requirements. Unfortunately, it does have one other difference that makes it way more controversial: uranium harvesting is occurring within drinking water aquifers.
Here’s how it works. Uranium is naturally present at trace levels in certain rock formations. A company in Texas is injecting oxygenated water into underground aquifers that are normally anoxic. This exposes the rock formations to different geochemistry and induces the uranium to dissolve into solution. Extraction wells recover the uranium-laced groundwater and precipitate out the uranium.
I’m sure the process works, but at what cost? Injection typically acts like a “bubble” that expands outward, with some mixing at the fringes. In other settings, like aquifer storage and recovery, it has already been shown that it’s virtually impossible to completely recover the injected “bubble” due to the mixing at the fringes. If you’re just talking about water storage, as in aquifer storage and recovery, that’s one thing. But we’re talking about intentionally mobilizing a contaminant in a drinking water aquifer. The mixing at the fringes means that uranium is going to stay in the groundwater, and potentially be pulled into someone else’s well eventually.
Maybe it doesn’t seem like a big deal now, especially if the aquifer in question isn’t heavily used. But Texas is really running out of water. The drought hit Texas hard this year, and their response has largely been to push for further conservation, rather than to expand long-term plans for water recycling or desalination (the only two realistic long-term options). So even if energy is at stake, I’d be awfully hesitant to sign away aquifers for uranium leaching, given that there are many sources of energy, but Texas is running short of water sources.
One magic bullet that engineers like to talk about for global warming is carbon capture and sequestration (CCS) — pumping carbon dioxide into the right water-saturated geological formations just might form carbonate minerals, converting carbon dioxide gas (greenhouse gas!) to a greenhouse-neutral rock. There are some hurdles, though, that haven’t quite been resolved. Most of the current CCS projects inject the captured gas into oil formations to enhance oil recovery — this is means that some of the gas often comes back out with the oil. It’s a different task to inject carbon dioxide to form minerals.
First, you have to have the right geochemistry in the water and in the rock. Carbonates are actually really slow to precipitate, and in some cases in the lab, oversaturated solutions took months to precipitate out solids (chemistry note: thermodynamics is separate from kinetics). Second, you have to get the pressurization right in the geological formation. On the one hand, this means putting in the proper well casing and piping (the “walls” of the well hole) — see the BP oil spill for an example of improper well construction. On the other hand, this means ensuring that the geological formation doesn’t open up cracks under pressure and leak that carbon dioxide back to the surface. (This is the suspicion of what might go wrong in some fracking, for example: that certain formations might open preferential pathways for migration of gases and solutions upward into overlying aquifers of drinking water. This is also an unknown, but not one that I’ll address here.) Finally, there’s the risk that injecting pressurized fluids will lead to increased seismic activity. This is currently being documented as it occurs, but we’re far from predicting when and where it might occur (other than “in locations where we injected stuff…after we injected the stuff” which isn’t that helpful for planning or engineering purposes).
Well, as usual, scientists are working on stuff that will eventually be useful. A recent paper evaluated a new way to detect carbon dioxide leaking into shallow soils from deep formations. Traditional technology has required an extensive collection of background data to understand how carbon dioxide might naturally move through a geological formation. But the new method uses measurements of nitrogen, oxygen, carbon dioxide, and methane in soil gas to distinguish between naturally occurring processes and an extra influx of carbon dioxide from, say, a CCS injection site.
This is pretty sweet, because knowledge is going to save money on these projects, as well as give clearer answers that the traditional method could. Plus, this will resolve a big question, at least in my mind, as to the viability of this technology. We can deal with it if the kinetics of carbonate mineralization are slow underground, but if the carbon dioxide gas leaks back out, it isn’t really sequestered after all…
There’s plenty of controversy around fracking in the US. But here we have a relatively informed public, with public officials who must respond to the balance of public opinion (whether it’s heightened oversight or direct election), and a pretty good basis of environmental laws. A fair number of countries have observed our issues with fracking and environmental hazards, and said, “Thanks but no thanks.” Notable bans have arisen in France and Germany, with proposals in the UK. But developing countries are hungry for the cheap energy source, and China, for example, wants in, to the tune of 6.5 billion cubic meters of gas by 2015 and 100 billion cubic meters by 2020 (the US produced some 170 billion cubic meters of natural gas in 2011).
The first red flag in my mind is cutting corners. My understanding is that the majority of the problems with aquifer contamination in Pennsylvania arose from shoddy well construction. Pardon my stereotyping, but Chinese industries aren’t exactly known for their meticulous high-quality work, especially when there’s profit to be made…This makes me nervous.
But the second red flag upsets me more: where will the frack water come from? China is not a country of abundant water resources, especially in the north. And in contrast to the US or Canada, its people have little recourse if they have complaints about depleted or contaminated water resources. Where will the water come from? Will Chinese central planners favor industry over people? It has happened before (just Google “chemical spill China” and see how many different incidents pop up, e.g., this one).
Never mind that it apparently takes 3 years to get environmental laws on the books, and wastewater disposal (currently one of the main problems with fracking in the US) is not one of China’s strong suits. Fracking might help the Chinese economy, but my bet is, it’s going to get really ugly really quickly. I’m glad we have home-grown natural gas to rely upon — far less guilt.
Researchers just published a paper that claims that hydraulic fracturing (“fracking”) poses a substantial risk to water pollution, but not how you might think. Fracking, at this point, is viewed as an evil process that’s destroying America’s heartland and poisoning major water supplies. Unfortunately, the public remains misinformed about actual threats to water supplies, and some widely popular “facts” claimed by fracking opponents turn out to be myths. Apparently neither side of the fracking debate is doing a good job of using science rather than emotion.
Which brings me back to the paper that just came out. The paper did not claim that fracking fluids would contaminate groundwater supplies, but rather stated that the risk from fracking wastewater is substantial to surface water bodies. Most of the water that is injected for fracking comes back out of the wells with the natural gas, and has high concentrations of naturally occurring salts, trace metals, and radioactivity due to its contact with the shale rock at depth. The large volumes of wastewater have the potential to overwhelm existing wastewater treatment plants (and downstream water treatment plants). The authors suggest that regulators should consider mandating procedures and methods to reduce wastewater volumes, so as to mitigate the risk of accidental wastewater release.
Oddly enough, the extensive drought across the US is already encouraging drillers to recycle their fracking wastewater to be reused for injection elsewhere. I’ve previously alluded to some of the research that’s being done to develop water reuse technologies for fracking, and now anti-fracking groups are pressing legislators to mandate water reuse and limit the amount of fresh water that can be used for fracking. To me, this is eminently sensible – it would be very hard for an environmental group to stop fracking altogether at this point, but it should be possible to hold drilling companies accountable to today’s environmental standards.
As you surely know, fracking gets a lot of publicity these days. One thing that gets less publicity is the science about fracking. In the case of the threat that fracking poses to drinking water supplies, things have gotten a little out of hand. The image of lighting one’s tap water on fire is pretty powerful stuff. But from what I’ve read, it sounds like the initial issues with fracking fluid and natural gas entering local aquifers derived mainly from poor well construction, specifically the well casings, by inexperienced workers eager to cut corners to make more money. Furthermore, the wells affected were generally private wells, owned by the very landowners making money off the natural gas being extracted. Private wells are not subject to the same rigorous testing as public wells and public water supplies, although the EPA recommends that well owners have their wells tested regularly. So these issues have not generally affected public water supplies.
That’s not what the public believes. A recent survey published in Environmental Science and Technology found that more Dallas residents worried that fracking was the greatest threat to their water supply [27%] than knew that they lived in a watershed [10%]. (Hint on the watershed question: you live in one.) This is not just another sad comment on the lack of public science education, rather this is a key piece of information when we discuss water use in general. Urban water use drives demand in most American cities, not industrial use. Cutting back on urban water consumption in places like Dallas, with a per capita water use of ~220 gallons per day, has far greater potential impact on the regional water balance than fracking could ever hope to have. The major coastal cities in California use closer to ~120 gallons per person per day, so it can be done.
I was riding BART the other night, trying to mind my own business despite a loud group of French teenagers. My ears perked up, though, when one teenager asked her chaperone, a young American woman about my age, if it was safe to drink the tap water everywhere in the US. At first I was annoyed that Europeans consider us so third-world as to even need to ask such a thing. (In China, for example, no city yet delivers safe tap water to all its residents.) But then the American’s response floored me: “Uh, sure, maybe except in areas with a lot of fracking.” It took all of my willpower not to launch into a tirade of facts about water. It’s frankly impressive how quickly environmentalists have won the P.R. battle about fracking. If only we could harness that momentum to educate the public about far more pressing issues when it comes to water supply…
A hot topic in the public sphere these days is fracking. I’m not interested in discussing the safety of fracking itself, but rather in the wastewater that it generates. You may have heard things like injecting wastewater underground can cause earthquakes, or that fracking wastes are contaminating surface waters across Pennsylvania. There’s science behind that. But there’s also an economic opportunity. The EPA will supposedly issue regulations for disposal of wastewater from fracking in the future, and the baseline condition is trucking the wastewater out of state, at least for parts of Pennsylvania. Lots of things are cheaper than that.
So start-ups are targeting this market and developing new technology. If they can treat the wastewater to a level where it can be reused for injection, then everyone wins: the net water withdrawals decrease, the treatment load on local municipal water and wastewater treatment plants decreases, and American ingenuity creates jobs. (Side note: no jobs would be created if we had no EPA. Keep that in mind, those who complain that regulations inhibit job creation.) Some ideas are a little out there, like the idea to use soybean oil to capture pure water from the wastewater stream, but I’m glad that they’re thinking about it. With costs like $15 to ship a barrel of wastewater from Pennsylvania to Ohio for disposal, or $5 million to drill a new disposal well, there’s a lot of room to be creative.
I find it ironic that recent research has found that fracking in and of itself produces virtually no risk of earthquakes. Carbon sequestration, on the other hand, is very likely to generate earthquakes, partly given that the easiest formations to find and inject CO2 into are the most likely to produce large earthquakes. It’s almost as if the earth itself is telling us to continue fracking and forget carbon sequestration…
The real issue, of course, is that injecting large quantities of water is likely to cause earthquakes in any formation. This means that the common fracking procedure of wastewater disposal via injection back into the original formation is also risky. But steam appears to be A-OK. Bring it on, fracking…