Use of gasoline releases carbon dioxide, carbon monoxide, nitrogen oxide, and hydrogen carbons causing buildup of greenhouse gases in the atmosphere, acid rain, and air pollution. NASA came up with the idea of bacterial car. It involves using human waste as the alternate fuel to run a car. A particular type of bacteria belonging to the Geobacteraceae family feeds on, and can decompose, organic material. They also have the unique ability to move electrons into metal. This means that under precise conditions, Geobacter metallireducens microbes can both process waste and generate electricity.
Why should I be aware of this?
Alternate source of energy, which is cheaper and more efficient as compared to current fuel, is the need of the hour. It should also be eco-friendly. As society is unlikely to run out of human waste anytime, this is the epitome of a sustainable technology. Sewage treatment plants could one day double as gas stations. The waste stream from society is being turned around, and providing energy and transportation fuel for the society.
All about bacterial car
Among the first instances, the USA's Orange County Sanitation District is readying to convert human waste into hydrogen fuel in a first-of-its-kind attempt to turn sewage into a salable product.
Methane gas from sewage will be used to provide three separate streams of energy.
First, the methane will be used to generate electricity in the traditional way. Then the waste heat from the fuel-cells device will be recaptured, and pumped back into the digester to help heat the sewage. And finally, hydrogen will be chemically separated from the methane and pumped into storage tanks, where it will be ready for use in hydrogen cars.
Though small amounts of carbon dioxide will be emitted during the process, there will be no net increase of carbon in the atmosphere a heat-trapping gas because it is generated from waste gases. And it produces only tiny amounts of other pollutants – far less than produced in the more common method of stripping hydrogen from natural gas.
Engineers in Thailand turned to human faeces in an attempt to find a new source of energy. They have been retrieving excrement and recycling it into what they are tastefully calling "bio-oil".
Traditionally they make their oil after burying and rotting animal and vegetable matter under layers of sediment and rock. The resulting heat and pressure transform the organic matter into oil over hundreds of thousands of years. The Thai engineers have speeded up the process by developing a reactor which works by blasting very hot nitrogen gas over human waste. The resulting product, they say, is a high quality fuel which can power car engines.
- Though the process of converting human excrement into valuable fuel is expensive, scientists believe it will become more economically viable as natural oil supplies dwindle. 
- In a Rwandan prison, prisoners' feces are converted into combustible "biogas," or methane gas that can be used for cooking. It has reduced by 60 percent the annual wood-fuel costs which would otherwise reach near $1 million, according to Silas Lwakabamba, rector of the Kigali Institute of Science, Technology and Management, where the technology was developed. 
- Bacterial Fuel: The Energy of the Future
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