A Canadian company is creating an alternative green fuel from a new source of energy that was under our noses all along - human sewage. Scientists at biofuel group Dynamotive say the oil produced from human waste can be used instead of fossil fuels to generate heat and power in diesel engines and boilers. They have successfully carried out the transformation on a pilot scale and are looking at ways to scale up the process to commercial quantities.
Andrew Kingston, president and chief executive officer of Dynamotive, said: "There are no process issues at this point to stop us using human sewage sludge. If we can supply the oil then people will use it." In February 2005 the company opened a commercial-scale plant in Ontario that produces 22,000 tonnes of bio-oil each year from waste wood chips and sells it to local industries.
Mr Kingston said more than 100 types of biological waste could be used as feedstock. The company has already commercialised oil production using wood separated from construction waste and coffee bean shells. "We're now looking at dirtier wastes like chicken litter, cow manure and household garbage," he said. The wastes are flash-heated at 400-500C in the absence of oxygen, a technique called pyrolysis, and the resulting carbon-heavy gases condensed into a dark
brown, dense oil. Other hot gases are recycled to help heat the process, which makes it about 80% efficient.
Such biofuels are considered environmentally benign because the carbon produced when the fuel is burnt was absorbed from the atmosphere by the plants or trees used to make it. The fuels are usually produced through the fermentation
of crops or by squeezing oil from seeds.
Source: David Adam The Guardian
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