Human Waste For Electricity, Do You Support It?

Plugging into the power of sewage
19:00 10 March 2004
Exclusive from New Scientist Print Edition. Subscribe and get 4 free issues.
Celeste Biever
 
 
Enlarge image
The sewage-powered generatorTools
  Related Articles
Sewage sludge bulks up house bricks
31 August 2002
Composting toilets key to global sanitation, say scientists
18 March 2003
Ski resort recycles sewage into snow
11 April 2002
Search New Scientist
Contact us
Web Links
Bruce Logan, Penn State University
Microbiology, University of Massachusetts
Sewage treatment, Wessex Water
 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.

Even better, the device breaks down the harmful organic matter as it generates the electricity, so it does the job of a sewage-treatment plant at the same time. Penn State's microbial fuel cell (MFC) harnesses chemical techniques similar to those the body uses to break down food - but diverts the electrons liberated in the reactions to produce electrical energy.

"There are extraordinary benefits if this technology can be made to work," comments Bruce Rittmann, an environmental engineer at Northwestern University in Illinois.

Many developing countries urgently need sewage processing plants, for example, but they are prohibitively expensive, largely because they use so much power. Offsetting this cost by producing electricity at the same time could make all the difference, says Bruce Logan, who led the development team at Penn State.

Slurry of bacteria
Sewage contains a slurry of bacteria and undigested food, consisting of organic matter such as carbohydrates, proteins and lipids. The bacteria found in sewage treatment works use enzymes to oxidise organic matter, in a process that releases electrons.

Normally the electrons power respiratory reactions in the bacterial cells, and are eventually combined with oxygen molecules. However, by depriving the bacteria of oxygen on one side of the MFC, the electrons can be wrested from them and used to power a circuit.

The MFC comprises a sealed 15-centimetre-long can with a central cathode rod surrounded by a proton exchange membrane (PEM), which is permeable only to protons. Eight anodes are arranged around the cathode (see graphic).

Bacteria cluster around the anodes and break down the organic waste as it is pumped in, releasing electrons and protons. With no oxygen to help mop up the electrons, the bacteria's enzymes transfer them to the anodes, while the protons migrate through the water to the central cathode.

Polarised molecules on the PEM encourage the protons to pass through to the cathode. There they combine with oxygen from the air and electrons from the cathode to produce water. It this transfer of electrons at the electrodes that sets up the voltage between them, enabling the cell to power an external circuit.

Glucose solutions
The Penn State team's device is the first MFC that is specifically designed to produce electricity by processing human waste. Previous designs have only run on glucose solutions.

As yet his design is only producing a tenth of what he calculates its potential power output could be. Even so, if scaled up, this system would produce 51 kilowatts on the waste from 100,000 people, Logan says. He hopes to be able to boost its efficiency by increasing the surface area of the anodes or by finding more efficient anode material.

Microbiologist Derek Lovley of the University of Massachusetts at Amherst believes the most elegant aspect of Logan's MFC is its single-chamber design, which makes it very easy to scale up. Most glucose-powered MFCs comprise two anode and cathode chambers, separated by a PEM.

However, Lovley believes generating power from waste water on a large scale is a long way off: "One way to think of this technology is that it is currently at the state of development that solar power was 20 to 30 years ago - the principle has been shown, but there is a lot of work to do before this is widely used."



http://www.newscientist.com/article/dn4761-plugging-into-the-power-of-sewage.html

The claim that Solar Panels are Expensive in a place like Nigeria and hence not affordable is a myth. It is not based on fact but people's perception of the technology and mostly push by suppliers of generators to sell their products. Anyone in Nigeria can start on Solar today and in a matter of years reap the benefits of having solar as against generators and more. The average Nigerian family spends at least naira 100k a year on fueling generators and this does not include the price of the generator and other tools which run way into the hundreds of thousands on initial buy.




There is a house in Nigeria as we speak running off of solar energy. The total one time cost of Solar panels, equipment and installation to supply that 2 storey building with electricity 24 hours of the day is about $5000. Below is the cost of operation


Year One TOTAL  POWER COST
Solar Panels $ installation ~  $5000 ( Just in case you may need to add frames to hold the panels or you can do it yourself)
SunLight , Free

Year Two TOTAL  POWER COST

Solar panels maintanance fees,  $50 ( should anything happen that you even need maintainance for
SunLight , Free


Year Three TOTAL  POWER COST

Solar panels maintanance fees,  $50 ( should anything happen that you even need maintainance for
SunLight , Free

Year Four TOTAL  POWER COST

Solar panels maintanance fees,  $50 ( should anything happen that you even need maintainance for
SunLight , Free

Year Five TOTAL  POWER COST

Solar panels maintanance fees,  $50 ( should anything happen that you even need maintainance for
SunLight , Free


Year Six TOTAL  POWER COST

Solar panels maintanance fees,  $50 ( should anything happen that you even need maintainance for
SunLight , Free

Year Seven TOTAL  POWER COST

Solar panels maintanance fees,  $50 ( should anything happen that you even need maintainance for
SunLight , Free



,  you get the idea now . Now how much more expensive is this compared to what you currently have to deal with now??? In the first year alone, put together the amount you had to pay for the generator, the inverter and then how much you ended up paying to fuel the generator for the first year alone . Now put it together over time and tell me how much more expensive it is compared to solar??

I believe the main reason why Nigerians are not using solar much is cause instead of actually doing their research, people believe what they hear and are told of it and this puts more money into the sellers of generators and inverters for those as well as continues to put money into the pockets of the oil industry at the cost of the environment. Solar is not expensive if you consider it costs almost the same amount it would cost you to install and fuel a generator the first year alone. After the initial cost, it is practically free of charge since you do not have to fuel it and most of the panels come with at least 10 years warranty ( meaning you get at least 10 years out of use of it) and you get 24 hour electricty with no noice pollution and not environmental pollution of any kind.


Right now Nigerians spend about $150 Million dollars on generators and fuel to gas them up EACH YEAR. We do not understand that this same can be spent one time for most of the country one and for all for power supply for at least 10 years. We need to start doing research instead of spewing the same old news which only amounts to repeating information that is passed down to us by people who themselves do not do their homework. 

How it works?

All energy comes from renewable energy sources like wind, solar, waves, hydro and biomass. The energy is either used directly as electricity or stored in hydrogen for use in transportation or to create electricity when the sun is not shinning or the wind is not blowing. The renewable energy is stored in hydrogen by splitting water into hydrogen and oxygen by use of electricity. This process is called electrolysis. Other productions methods will also be used to create hydrogen from fossil fuels. After the production hydrogen functions as an energy carrier that can be used to supply energy wherever it is needed. A fuel cell is used to convert the hydrogen into energy again. In the fuel cell hydrogen and oxygen (air) reacts and creates water as the only emission. The reaction creates electricity and heat that can be used in various applications. As fuel cells are very scaleable they can be used in all applications that needs energy, ranging from mobile cell phones, cars, buses and even as large heat and power plants. Fuel cell as a technology will be the next energy innovation step that will bring progress and prosperity to our societies, with as great an impact, as the steam engine and the combustion engine have had.

Relying only on renewable energy also solves the threats of oil depletion and pollution in the present energy system. This also makes it possible for everybody to produce their own energy creating more politically stability and benefits to all of us. But much has to be done before hydrogen is for real.
========
Therefore, do your research homework to resolve Nigeria Electricity solution in the name of hybrid renewable energy.

Nice thread indeed but it won't cause any change to Nigeria.
My brothers, it's good we are doing this but how powerful are we to implement this, even if the top goverment officials know this; they will just turn deaf eyes to it.

@Kobojunkie
I agree that solar energy is an option to consider, but your analysis are rather very optimistic

1. An average family does not spend $100k/year or do you mean 100k Naira?
2. You have to change your battery banks every 2-3 years, because of of our temperature and humidity. Batteries do not last forever! and these batteries are not cheap
3. When you increase number of solar panels, you need to increase your battery capacity.

What is the capacity of this $5k solar generator?
What type of backup batteries are you using? Ordinary or Deep cycle?

For a long-term solution, the hybrid system for non-grid power supply systems, is what I will recommend, just like uspry1, suggested

And for the solar system . . ., the capital outlay for a solar system,  which is about $6,000-$7,000 per KW is still too expensive for the average Nigerian home
An average home will need about 2.5kva.
We also need to take into consideration, the efficiency of the solar power systems

In the interim, I use a semi-hybrid system of inverter, generator and NEPA