Friday, March 30, 2012

Social Innovation: The Power of Sewage

There are so many smart new social innovation technologies coming out to create renewable fuels and power supplies. The latest discovery is that sewage plants are being used to not only treat waste but to also generate electricity.

This knowhow is devised by Prof Bruce Logan, an environmental engineer specializing in water systems at Pennsylvania State University in the U.S. and his team of researchers.

Professor Logan believes that by switching sewage plants from users to generators of electricity would be especially useful in developing countries.

Professor Logan has a vision. He recognizes that there are two billion people in the world who need sanitation, including a billion who need access to clean water. By helping these regions and giving them a waste treatment system, we also need to realize that these places also need the power and the resources to keep it going, which can be a drain on the community. However, by providing a waste treatment facility that can also generate electricity for lighting, or charging mobile phones well that’s a social innovation game-changer!

Sewage plants are where the treatment of domestic wastewater happens, where it goes through the process of removing contaminants from the wastewater and household sewage. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants. The end result is to produce an environmentally-safe fluid waste stream and a solid waste suitable for disposal or reuse (usually as farm fertilizers). Using advanced technology, it is now possible to re-use sewage effluent for drinking water, although till now, Singapore is the only country to implement such technology on a big enough production scale.

So, this new social innovation technology by Professor Logan works through a device that combines a fuel cell with other technologies to convert waste water treatment stations into power plants and provide the power for entire water grids. By bringing the two technologies together, Professor Logan and his team produced 0.9 kilowatt-hours of electricity per kilogram of organic waste. In contrast, sewage treatment usually consumes 1.2kWh per kilogram. Professor Logan says, “We certainly could take care of the whole water system: the treating and pumping of water, which currently requires substantial amounts of power.” This device can also be used with other types of waste to generate power.

In fact, Britain’s largest water and sewerage company, Thames Water has begun producing for the first time in Britain ready-to-burn fuel from sewage sludge (the solids found in sewage) where the sludge is dried into flakes. The flakes are transported to a purpose-built machine where they are then burnt off to generate electricity. Thames Water estimates that 16% of its electricity needs will be covered by this new type of social innovation— “poo power”— which is enough to run about 40,000 average family homes.

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