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New device harnesses sun and sewage to produce hydrogen fuel
R&D Magazine ^ | 10/11/2013 | none listed

Posted on 10/13/2013 4:49:24 AM PDT by Wonder Warthog

A novel device that uses only sunlight and wastewater to produce hydrogen gas could provide a sustainable energy source while improving the efficiency of wastewater treatment.

A research team led by Yat Li, assoc. prof. of chemistry at the Univ. of California, Santa Cruz, developed the solar-microbial device and reported their results in ACS Nano. The hybrid device combines a microbial fuel cell (MFC) and a type of solar cell called a photoelectrochemical cell (PEC). In the MFC component, bacteria degrade organic matter in the wastewater, generating electricity in the process. The biologically generated electricity is delivered to the PEC component to assist the solar-powered splitting of water (electrolysis) that generates hydrogen and oxygen.

Either a PEC or MFC device can be used alone to produce hydrogen gas. Both, however, require a small additional voltage (an "external bias") to overcome the thermodynamic energy barrier for proton reduction into hydrogen gas. The need to incorporate an additional electric power element adds significantly to the cost and complication of these types of energy conversion devices, especially at large scales. In comparison, Li's hybrid solar-microbial device is self-driven and self-sustained, because the combined energy from the organic matter (harvested by the MFC) and sunlight (captured by the PEC) is sufficient to drive electrolysis of water.

In effect, the MFC component can be regarded as a self-sustained "bio-battery" that provides extra voltage and energy to the PEC for hydrogen gas generation. "The only energy sources are wastewater and sunlight," Li said. "The successful demonstration of such a self-biased, sustainable microbial device for hydrogen generation could provide a new solution that can simultaneously address the need for wastewater treatment and the increasing demand for clean energy."

Microbial fuel cells rely on unusual bacteria, known as electrogenic bacteria, which are able to generate electricity by transferring metabolically generated electrons across their cell membranes to an external electrode. Li's group collaborated with researchers at Lawrence Livermore National Laboratory (LLNL) who have been studying electrogenic bacteria and working to enhance MFC performance. Initial proof-of-concept tests of the solar-microbial (PEC-MFC) device used a well-studied strain of electrogenic bacteria grown in the laboratory on artificial growth medium. Subsequent tests used untreated municipal wastewater from the Livermore Water Reclamation Plant. The wastewater contained both rich organic nutrients and a diverse mix of microbes that feed on those nutrients, including naturally occurring strains of electrogenic bacteria.

When fed with wastewater and illuminated in a solar simulator, the PEC-MFC device showed continuous production of hydrogen gas at an average rate of 0.05 m3/day, according to LLNL researcher and co-author Fang Qian. At the same time, the turbid black wastewater became clearer. The soluble chemical oxygen demand—a measure of the amount of organic compounds in water, widely used as a water quality test—declined by 67% over 48 hours.

The researchers also noted that hydrogen generation declined over time as the bacteria used up the organic matter in the wastewater. Replenishment of the wastewater in each feeding cycle led to complete restoration of electric current generation and hydrogen gas production.

Qian said the researchers are optimistic about the commercial potential for their invention. Currently they are planning to scale up the small laboratory device to make a larger 40-L prototype continuously fed with municipal wastewater. If results from the 40-L prototype are promising, they will test the device on site at the wastewater treatment plant.

"The MFC will be integrated with the existing pipelines of the plant for continuous wastewater feeding, and the PEC will be set up outdoors to receive natural solar illumination," Qian said.

"Fortunately, the Golden State is blessed with abundant sunlight that can be used for the field test," Li added.


TOPICS: Business/Economy; News/Current Events; Technical
KEYWORDS: energygeneration; greentech; sewage; solarenergy

1 posted on 10/13/2013 4:49:25 AM PDT by Wonder Warthog
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To: Wonder Warthog
If that’s true, that cesspool known as Washington DC should be able to provide us with an unlimited source of energy.
2 posted on 10/13/2013 4:54:55 AM PDT by AlaskaErik (I served and protected my country for 31 years. Progressives spent that time trying to destroy it.)
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To: Wonder Warthog

Too bad those thousands of politcians and White Hut occupants couldn’t be fed into a machine that will propel our vehicles.

Wonder what boondoggle will evolve from this discovery?


3 posted on 10/13/2013 4:58:15 AM PDT by IbJensen (Liberals are like Slinkies, good for nothing, but you smile as you push them down the stairs.)
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To: IbJensen

“Wonder what boondoggle will evolve from this discovery?”

Certainly it must be a strategy of “clean energy” scientists to put out press releases that create over-excitement and fawning press coverage, all with the ultimate goal of securing more government grant money. My guess is that most of these ideas are completely impractical or unworkable when scaled up.


4 posted on 10/13/2013 5:06:48 AM PDT by BlueStateRightist
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To: IbJensen
A communal crapping ground. Household toilets will be forbidden, unless you're in the ruling class of course. Everyone else will have to use the communal loo or at least be required to haul pee & poo to the depository.

It's for the children and the Earth Mother, so you better get in line and do it right or else.

5 posted on 10/13/2013 5:12:25 AM PDT by csvset
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To: IbJensen

Sounds like a self-sustainable power/waste disposal system for cities. Anything to get us to local control of energy would be a good thing. Therefore this invention will go the way of the Doe Doe bird.


6 posted on 10/13/2013 5:14:42 AM PDT by WVNan
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To: Wonder Warthog

———an average rate of 0.05 m3/day———

Hmmmm......


7 posted on 10/13/2013 5:20:16 AM PDT by bert ((K.E. N.P. N.C. +12 ..... Travon... Felony assault and battery hate crime)
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To: Wonder Warthog

I suppose they will institute “crap credits”.


8 posted on 10/13/2013 5:27:41 AM PDT by BuffaloJack (Gun Control is the Key to totalitarianism and genocide.)
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To: AlaskaErik
"If that’s true, that cesspool known as Washington DC should be able to provide us with an unlimited source of energy."

True. But it would be so much more satisfying to burn the bureaucrats and politicians directly, even though that energy supply wouldn't last as long.

9 posted on 10/13/2013 5:27:55 AM PDT by Wonder Warthog
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To: Wonder Warthog

I’d like a tank of sewage and a bright sunny day please!


10 posted on 10/13/2013 5:28:19 AM PDT by DannyTN
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To: BlueStateRightist
"My guess is that most of these ideas are completely impractical or unworkable when scaled up."

Often true. As Sturgeon's Law puts it "90% of everything is crap". But you've gotta do the research to find the 10% that are good ideas.

11 posted on 10/13/2013 5:30:05 AM PDT by Wonder Warthog
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To: BuffaloJack

I suppose they will institute “crap credits”.

LOL! Why not? They’ll come up with any bogus notion to tax.


12 posted on 10/13/2013 5:32:41 AM PDT by WKUHilltopper (And yet...we continue to tolerate this crap...)
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To: csvset
"A communal crapping ground. Household toilets will be forbidden, unless you're in the ruling class of course. Everyone else will have to use the communal loo or at least be required to haul pee & poo to the depository."

Any community above a certain size already has that. It's called "a sewer system". And those work just fine with "household toilets". But treating the wastes from those systems is not free.

13 posted on 10/13/2013 5:33:16 AM PDT by Wonder Warthog
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To: WVNan
"Sounds like a self-sustainable power/waste disposal system for cities. Anything to get us to local control of energy would be a good thing. Therefore this invention will go the way of the Doe Doe bird.

Waste treatment costs cities and towns a LOT. If the waste treatment part has even reasonable efficiency, it can offset (or maybe even eliminate) those costs, and put out energy at the same time.

14 posted on 10/13/2013 5:35:28 AM PDT by Wonder Warthog
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To: bert
"Hmmmm......"

Not unreasonable for the small lab cell they tested (pic is at original article link). Next step is to test the scaling laws of the system with their forty liter prototype.

15 posted on 10/13/2013 5:37:03 AM PDT by Wonder Warthog
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To: csvset

Its called a sewage treatment plant.


16 posted on 10/13/2013 5:43:37 AM PDT by bigbob
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To: Wonder Warthog

What do they plan to do with the hydrogen?


17 posted on 10/13/2013 5:48:59 AM PDT by Right Wing Assault (Dick Obama is more inexperienced now than he was before he was elected.)
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To: Right Wing Assault
"What do they plan to do with the hydrogen?"

I would guess that they would probably use it in a fuel cell to generate electricity. It is, after all, the perfect fuel for such cells. Just making the wastewater plant "energy self supporting" would be a major plus in the budget of pretty much any city of size. If the overall process turns out not to produce "sludge" or even reduces the amount of same that has to be disposed of as solid waste would be another significant plus.

I think the correct way to look at this is as a way to make wastewater treatment much more efficient/less costly, not as a major energy producer.

18 posted on 10/13/2013 5:58:04 AM PDT by Wonder Warthog
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To: Wonder Warthog

It won’t work.
They will try to use genetically modified microorganisms.

No No GMO!


19 posted on 10/13/2013 6:01:41 AM PDT by Zuse
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To: Wonder Warthog
I built a biological solar cell in 1978 while in college. It used halobacteria, which is a completely different mechanism than what these folks are describing. I'll leave it with the point that scale up to some thing viable both mechanically and commercially is a mighty tall mountain to climb.

IMHO, if this process goes farther than a lab curiosity,, it will main be because it is used as a pretty bauble attract varieties of grant funds.

20 posted on 10/13/2013 6:07:47 AM PDT by Hootowl99
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To: BlueStateRightist

“My guess is that most of these ideas are completely impractical or unworkable when scaled up.”

But, you have to give the Chinese guy some credit for understanding energy inputs and outputs - unlike the idiots in the government pushing ethanol...


21 posted on 10/13/2013 6:09:34 AM PDT by The Antiyuppie ("When small men cast long shadows, then it is very late in the day.")
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To: WKUHilltopper

“LOL! Why not? They’ll come up with any bogus notion to tax.”

We already pay a tax here for schools every time we take a crap, a school tax - it’s for the children of course...


22 posted on 10/13/2013 6:11:27 AM PDT by The Antiyuppie ("When small men cast long shadows, then it is very late in the day.")
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To: Wonder Warthog

Yep, you nailed on several important points. First, solids are going to be produced and disposed of as with current technology. Wouldn’t surprise me if if this used an old fashioned stabilization pond type bioreactor, which takes a lot of area and very likely to require tertiary treatment that would tilt the economics the wrong direction.


23 posted on 10/13/2013 6:26:03 AM PDT by Hootowl99
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To: IbJensen

It’s perfectly scaled for cat boxes!!


24 posted on 10/13/2013 8:25:41 AM PDT by SgtHooper (The last thing I want to do is hurt you. But it's still on the list.)
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To: WVNan

“Doe Doe bird”
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

That’s a new one on me, is the male of the species called a Buck Buck bird?


25 posted on 10/13/2013 9:38:52 AM PDT by RipSawyer (The TREE currently falling on you actually IS worse than a Bush.)
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To: AdmSmith; AnonymousConservative; Berosus; bigheadfred; Bockscar; cardinal4; ColdOne; ...

Thanks Wonder Warthog.
Either a PEC or MFC device can be used alone to produce hydrogen gas. Both, however, require a small additional voltage (an "external bias") to overcome the thermodynamic energy barrier for proton reduction into hydrogen gas. The need to incorporate an additional electric power element adds significantly to the cost and complication of these types of energy conversion devices, especially at large scales. In comparison, Li's hybrid solar-microbial device is self-driven and self-sustained, because the combined energy from the organic matter (harvested by the MFC) and sunlight (captured by the PEC) is sufficient to drive electrolysis of water.
Ludicrous.


26 posted on 10/13/2013 11:51:34 AM PDT by SunkenCiv (It's no coincidence that some "conservatives" echo the hard left.)
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To: RipSawyer

LOL. Could be. I wasn’t sure how to spell it. It’s a very old expression. Dodo Bird? Sort of like Snipes.


27 posted on 10/13/2013 2:29:27 PM PDT by WVNan
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To: Hootowl99
"First, solids are going to be produced and disposed of as with current technology."

At this point, there is no data to decide one way or the other. If it turns out NOT to generate solids, IMO, this would be a major plus.

"Wouldn’t surprise me if if this used an old fashioned stabilization pond type bioreactor, which takes a lot of area and very likely to require tertiary treatment that would tilt the economics the wrong direction."

For this test reactor, they used two beakers. A wee bit early to talk about ponds and such.

28 posted on 10/13/2013 3:42:56 PM PDT by Wonder Warthog
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To: SunkenCiv
"Ludicrous."

Which part?? I kind of thought that the idea of combining the two approaches to overcome a disadvantage each has as a stand-alone technology was good innovative thinking.

29 posted on 10/13/2013 3:45:41 PM PDT by Wonder Warthog
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To: WVNan
"Dodo Bird? Sort of like Snipes."

The DoDo bird "was" quite real. A not-very-bright flightless bird native to a small island (Mauritius) in the Indian Ocean. They had no fear of humans, and were killed off by hungry sailors.

30 posted on 10/13/2013 3:58:08 PM PDT by Wonder Warthog
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To: Wonder Warthog

Rather than using the photovoltaics to directly generate electricity for the grid (via DC to AC conversion of course), they’re using it to make the digestion process “self-sustaining” — then turn methane into electricity in a fuel cell in order to produce hydrogen. Pelion on Ossa.


31 posted on 10/13/2013 4:21:30 PM PDT by SunkenCiv (It's no coincidence that some "conservatives" echo the hard left.)
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To: Wonder Warthog

Thank you for the Natn’l Geographic presentation. I knew that......of course I knew that....didn’t I? LOL


32 posted on 10/13/2013 6:53:25 PM PDT by WVNan
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To: SunkenCiv
"Rather than using the photovoltaics to directly generate electricity for the grid (via DC to AC conversion of course), they’re using it to make the digestion process “self-sustaining” — then turn methane into electricity in a fuel cell in order to produce hydrogen. Pelion on Ossa."

It isn't methane they're converting, but the larger and more obdurate molecules (note the statement "dark wastewater becomes clearer"). Methane isn't "dark".

So they're using energy from the photovoltaics and energy from the hydrocarbons to get more total energy than either can get when run as a standalone process, while simultaneously cleaning the water. This still sounds like a "good thing" to me.

As to "why hydrogen" instead of direct electricity?? I dunno. I kind of wondered that myself. It may have to do with what their "electrogenic bacteria" are capable of.

33 posted on 10/14/2013 4:09:24 AM PDT by Wonder Warthog
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