Posts Tagged ‘Wastewater’

algae-open-pondChlorella sp. is a species of algae that has a significant proportion of fatty acids to its body mass. For humans, this can be a problem. But, in a world needing more clean energy, fatty biomass is considered a promising option by many scientists and engineers.

Why algae? Algae can grow in a body of water almost anywhere. We don’t need to use any of our precious farmland to grow it. Water conservationists may initially be concerned, but a group of scientists found that Chlorella sp. thrives in our waste water. Not only that, it cleans up the water, removing ammonia and a host of toxic metals. According to their report, the algae could be used to help clean up waste water at municipal water treatment plants then harvested for biofuels.

graph_algaeI had a chance to speak with Dr. Martin Poenie, Associate Professor in Molecular Cell & Developmental Biology, at The University of Texas at Austin. The Poenie Lab is helping to develop a technique for harvesting the oils from algae that could greatly reduce cost. Dr. Poenie also told me algae can be a significant source of phosphates, which we use in fertilizers. One of the most significant things about algae biofuels, is their small carbon footprint and high energy content. CO2 is sequestered during the growth phase of the algae and it is not released until the fuel is burned. On the whole, biofuels from algae look promising, and the variety of products that can be derived from it will make algae farming even more profitable.

Texas could do more to capture the energy and job benefits from this home grown energy source. Texas Legislature should act to strengthen renewable energy goals. HB 303, SB 1239, and HB  723 would all be good steps in the right direction.

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Are small earthquakes associated with hydraulic fracturing for gas?  Recent quakes in Ohio and Arkansas have taken many people by surprise, including a 2.7-magnitude earthquake that rocked Ohio on Christmas Eve, followed by a  4.0-magnitude quake on New Year’s Eve bringing the total to nine last year.  All of the quakes were recorded within a 5-mile radius of a hydrolic fracturing wastewater injection well.

Fracking and EarthquakeGas industry executives say there’s no hard evidence that their activities are causing these quakes. But some scientists say it’s certainly possible and have found that pumping water away from underground mines (to keep them from flooding) changes the dynamics of stress in rock formations enough to trigger a quake.

Some rock is saturated with water — the water occupies pores between rock particles. This creates what’s called “pore pressure” and keeps the formation in a sort of equilibrium. If you suck the water out, particles tend to collapse in on themselves: the rock compresses. Add water, and you push particles apart. So moving water around underground can affect the stresses on those formations.

Hydraulic fracturing pumps a lot of water underground, where it’s used to crack the rock and liberate gas. This may cause tiny quakes, but fracking goes on for a day or two, and the quakes are small.  But the recent quakes reported in Ohio and Arkansas are associated with the waste-water wells used to dispose of the fracking water, not the fracking wells. The water first used in fracturing rock is retrieved and pumped into these waste wells under high pressure and as much as 9,000 feet deep. It’s this pressure that can actually create earthquakes.

A few geologists are familiar with these induced or triggered quakes. They’re rare and usually small, but now fracking is creating thousands of waste-water wells, often in heavily populated areas that historically have not been seismically active. That means even small quakes get noticed.

We could avoid creating earthquakes by recycling the fracking waste-water rather than injecting into waste wells, however when the state of Pennsylvania tried it they found that waste-water treatment plants couldn’t get all the toxic material out of fracking water, and the “cleaned up” water returned to rivers wasn’t clean enough. So now they ship it to to Ohio, where there is a more relaxed regulatory environment.

The U.S. Geological Survey (USGS) is working on ways to head off quakes from waste-water wells by performing seismic surveys before drilling the wells or limiting the amount of water going into wells.  USGS geologists have learned that the more water injected, the bigger an ensuing quake.

Flamable tap water, earthquakes – this fracking business just keeps getting better and better . . .

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