The Power of Sewage

Eridanis writes ""The waste you flush down the toilet could one day power the lights in your home. So say researchers at Pennsylvania State University who last week revealed they have developed an electricity generator fuelled by sewage." Hey, it seems that EA will have to create a new building for Simcity!"

Comments

slightly different approach....

[tanveer1979]

I am aware of Bio-Gas plants which are used in villages in India. The Animal waste is dumped into the "pit" Methane is released and it is used for cooking. But I guess this method is more efficent.
Good for farms where lot of animal waste is there

Re:slightly different approach....

[qtp]

Locate the plant where the waste is being treated, like they do already in Lithuania Germany and Oregon.

You are already moving the sewage around as it is, so that expense is already there. The waste output of the biogas fermener is much safer than the sludge that existing sewage plants produce, and it can be further composted to produce safe, high quality, organic fertilizer.

There are also existing farm waste facilities (as was previously discussed here on /.) and existing technology to tap land fills in the same manner. It's energy that can be easily converted to a usable, transportable form (electricity) that wopuld otherwise go to waste. The gasses that are being converted are greenhouse gasses (mostly methane) that are not readily sinkable, and the waste products from the fuel cell are only (easily sinkable) CO2 and water.

The other implication of this technology that is less spoken about is that it decentralizes the source of energy away from the fossil fuel companies and spreads the profits closer to the community where the energy is being produced, either through lower costs for waste treatment, or through direct profit from the sale of the electricity if the facility is privately owned. This means lower costs for energy and lower trade deficit.

It's a winning situation for those who live in communities that take advantage of this, and the only people who lose out are the energy companies.

Electricity from Waste

[eples]

Something similar has been around since the 50's called "digesters" that use natural waste and the methane byproduct to power generators. It may have been invented at Penn State as well, but they are expensive so there are only about 20 of them around the country.

Re:Electricity from Waste

[ross.w]

IAAWWE (I am a wastewater Engineer)

Actually most sewage plants have a digester in them (or several).

Most Sewage Treatment Plants that have anaerobic digesters (the kind that produce methane) simply flare the gas off, because the quantity of gas produced doesn't warrant the expense of setting up to re-use it.

Seafield Sewage Works in Edinburgh, Scotland does though. It was completed in 2000. If you fly into Edinburgh airport over the Firth of Forth, you can see a row of six large pink tanks near the docks. These are the digesters at Seafield. (The reasons why they are pink are complex and architectural, not functional).

Bondi STP in Sydney used to re-use methane for generating power the 1960s, but the the technology was primitive, and the sulphides in the gas made the engines expensive to maintain and they were abandoned.

Now in Australia, with green energy credits on offer, many water authorities are having another look at making use of their methane.

Re:Electricity from Waste

[kfg]

Digesters have been around for about 100 years. During WWII with gas rationing they became quite common, one version even coming on a trailer you could pull behind your car while collecting manure, and then run your car from.

During the gas crunch of the 70s digesters popped up all over the place and there was hardly an issue of Mother Earth News that didn't have some new design/application of a digester featured in it showing how you could power your farm/homestead on shitty methane.

There are still thousands, perhaps tens of thousands, of digesters scattered across Americas rural areas. Virtually all of them are built by the owners out of scrap materials for nearly nothing.

Perhaps there are only 20 of this expensive commercial variety. A lot of companies like to make money by taking old ideas that people in general have forgotten about, plate them in chrome, and sell them as the latest technology for a premium price.

Go to the library. See if they've got back issues of Mother Earth News from the 70s and 80s. Lots of good digesters ideas in there, although often a bit crudely implimented.

The mere idea of excrement for fuel energy goes back to God only knows how long. It's certainly prehistoric. The Plains Indian relied on Buffalo Chips for fuel, and the Indian Indian still does today.

Latrine Officer was one of the most important posts in Napoleon's army. His job? To retrieve human excrement. It was too valuable an energy source to waste. They used it to be able to make their own gunpowder as they traveled, which is one of the reasons that Napoleon's armies seemed to be able to pull off almost magical feats of translating themselves from one location to another and arrive ready to fight.

Shit is energy. We know that. We've always known that. We've known that that energy can be extracted as natural gases and used to run combustion engines and turn electric generators for over a century. It's news so old it's boring.

It's even a reasonably viable way to go about making energy, if you live on a small farm with lots and lots of animals producing lots and lots of shit you need to do something with.

For city dwelling humans, well, it will never be anything more than a suppliment to other forms of energy. Something you can use because it's there, but nothing to be relied upon.

Why? Well, how much did you shit today? Does that amount of shit convert into the electricity you used?

Not even close.

You'll need a lot of other animals who don't watch TV shitting for you as well. Like on a farm, say.

And nevermind the fact that most of the shit (including human) is more valuable as a fertilizer (which is where much of the treated sewage is going right now) than it is as a fuel, so you're invoking the whole food for fuel argument. It may be better to burn that fuel we can't eat, or use for food production, and eat the fuel we can.

KFG

Reminds me of an article in Discover

[MrPoopyPants]

This article got me pretty excited about the future of waste/energy. I'd love to see those piles and piles of junk and biowaste turned into useful energy.

The conspiracy theorist within me fears that these types of technologies will not take off because oil companies have so much power.

Old News for those in rural areas

[backtick]

http://www.energy.state.or.us/biomass/digester/dig estech.htm

Lots of places have these; I see someone say "There are only a few in production" fairly often, but this is incorrect; there are more and more every year. Dairy farms are using them in large numbers, but the city of portland has a fairly large one (see http://www.energy.state.or.us/biomass/fuelcell.htm )
that processes the residue from 82 million gallons of wastewater a day.

As an example of the economics, see:
http://www.eco-farm.org/sa/sa_dairy_synopsis _diges ter.html#eco

Payback in 6 years. Not bad, considering lots of places give grants, as these help cut down on groundwater pollution. You can have payback in 3 years, and then start making money on the juice you sell.

OT question: Why not dual flush toilets in USA?

[tetranz]

In my former part of the world, nearly all toilets in homes are dual flush to save water. They have two buttons, one gives a half flush, the other a full flush. Its not rocket science to figure out when you need which. An american visitor had not seen this before.

Now that I live in the US, I wonder why such technology doesn't exist here. It seems like a much better way to save water than the problematic 'low flush' toilets common the US.