Wastewater treatment plant sludge has been considered a potential source of energy since these plants were first built in England about 150 years ago. The idea seems so obvious that every elementary environment schoolteacher is convinced that only stupid or evil people is stopping it from happening. During the years I was a Plant Manager and later in the Water Authority, I was bombarded with ideas and proposals from all kind of idealistic but naive "green" people, normally a young female school teacher, who wanted my co-operation for her pilot project. Instead of the futility of explaining the energy balance of the process, which is negative, I always said yes and watched her to fade away when the practical issues started to appear.
Now I read in a trade paper that a Nevada university has designed yet another of these sludge-electricty schemes.
Our plan is to test the unit by about May 15," Chuck Coronella, principle investigator for the research project and an associate professor of chemical engineering, said. "We're designing, building and assembling a continuous-feed system that will ultimately be used to generate electricity. We'll run experiments throughout the summer, creating a usable dried product from the sludge." The experimental carbon-neutral system will process 20 pounds of sludge per hour, drying it at modest temperatures into solid fuel that will be analyzed for its suitability to be used for fuel through gasification and, in a commercial operation, ultimately converted to electricity. The refrigerator-size demonstration unit will help researchers determine the optimum conditions for a commercial-sized operation.The obsessive designing of small-scale pilot sludge to electricity models reminds me of India's scientists eternal building of cow-shit to cooking-gas projects. America is a very large and diverse country, so fortunately this project is not representative of its intellectual level.
"The beauty of this process is that it's designed to be all on site, saving trucking costs and disposal fees for the sludge," Victor Vasquez, a University faculty member in chemical engineering said. "It uses waste heat from the process to drive the electrical generation. It also keeps the sludge out of the landfill."
Estimates, which will be further refined through the research, show that a full-scale system could potentially generate 14,000 kilowatt-hours per day to help power the local reclamation facility. The demonstration-scale project is a collaboration with the cities of Reno and Sparks, operators of the wastewater plant. The city councils signed an interlocal agreement recently to allow the research to integrate into their operation, providing space for the experiments, the dewatered sludge and other resources to help make the project a success.
"Economically, this makes sense," Coronella said. "Treatment plants have to get rid of the sludge, and what better way than to process it onsite and use the renewable energy to lower operating costs." Coronella added, "This demonstration gives the University an opportunity to involve students in development of waste-to-energy technology, which ultimately will benefit the community. It's a win-win for everyone involved."
The University's Technology Transfer Office, with assistance from the College of Business, is supporting the project with plans to make the system available to hundreds of communities around the country that operate water treatment plants.
9 comments:
Most of the "green" energy type projects are like this - they just don't have the energy density of good old dinosaur juice. Even when they manage to squeeze out more energy than they consume, the net contribution to overall energy consumption is so negligible as to be completely insignificant and the cost is rarely competitive especially if you include capital costs. But new ones get proposed every day anyway. They are like the perpetual motion machines of our time.
K
You've confused my scientifically-ignorant self. You say the energy balance is negative, which sounds like a very straightforward "this-can't-possibly-work" argument. But then you have an associate professor and a faculty member in chemical engineering working on the project, and a credulous trade journal reporting on it. Shouldn't the infeasibility be obvious to them? Or is it not as straightforward as you imply?
Normally, we are talking about a sludge that spent a month in an anaerobic digestor and have very little combustible material left. Little as it is, it has some energy left. The problem is that the sludge is wet (say 95% water), the organic material is mostly synthetic plastics, and has high concentration of inorganic material. Even dry sludge burns very badly and you need a high temperature incinerator to destroy the plastic material. The Japanese normally incinerate the sludge, but it is an energy negative operation. I dont think that building small village level sludge incinerators will add much energy to the 100 quadrillion BTUs (105 exajoules, or 29 PWh) produced each year in the USA.
The small scale village sludge-electricity concept is an imbecility. It is like Mao Tze Tung's village iron works, during the Great Leap Forward. The Chinese learned the lesson and grew up from this third-world appropiate technology retard thing, and are fully focused on building giant modern industrial scale plants.
Cooking off cowdung gas is not a nice way to make dinner, apparently it leaves a bad odour in the food. Enterprising Indian student scientists have another old standby - the generation of electricity with sludge gas. Usually they generate enough electricity to give each household in a village a staggering 25 watts, quite sufficient for a happy yokel to make out a rock, before stumbling over it on the way to the toilet.
I heard about an Indian fakir that learned to create electric tension with his mind. He had a third eye glued on his brow, and a small blue LED lamp inside, connected with thin wires to his left and right earlobes, respectively. Very impressive.
(I just made this up.)
This surely will never see the light of day as a full scale project - this is just a boondoggle for grant money. Read between the lines.
K
Yes, I know that it is a stupid green project beloved by America's current governing elite. But dont they invest in more intelligent pilot projects? Always the same solid waste-to-compost and wastewter-sludge-to-electricity and irrigating the garden with grey water and other cretinous infantile projects.
Because greens are fixated at the infantile playing with kaka level. Plus to them big = evil (also infantile), so projects must involve village blacksmiths, etc. This is where Obama's mama was 40 years ago and the left has not progressed one iota since then except they have latched onto "global warming" as the flavor of the week. But the sky is always falling - the birds are dying, the trees are dying , the whales are dying, etc.
K
The western world is no longer controled by adults.
Anon.
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