Energy from wastewater

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Wastewater in an energy resource[edit]

The treatment of wastewater using conventional methods consumes significant amounts of energy.[1]

However, wastewater actually contains biochemical energy, which is normally thrown away, or worse, discarded as pollution. Biochemical oxygen demandW is a measure of pollution, but also indicates the energy content of the wastewater.

Methods of extracting energy[edit]

Biogas is one method with the potential for use as an appropriate technology.

Various waste-to-energyW technologies including incinerationW can be used to dispose of solid waste. This includes dried sewage sludge.W

Microbial fuel cellsW are a completely new method of energy recovery, and are currently under development. They could be used to produce electricity; also they could produce hydrogen - the BioElectrochemically Assisted Microbial Reactor (BEAMR) method is claimed to yields four times the hydrogen of fermentation alone.[2]

Footnotes[edit]

  1. According to one estimate, "In the USA... 5% of electricity we produce is used to treat water and wastewater." - from Microbial Fuel Cells, B.E. Logan, 2005. Does this include the cost of contructing colleciton and treatment facilities, including the embedded energyW in the materials?
  2. 2005 Popular Mechanics Breakthrough Awards (published in the November 2005 issue). According to this update (Nov 2007) efficiency has reached 82%. For more information, see Microbial Fuel Cells, by Bruce Logan of Penn State University (2005), who won a 2005 Popular Mechanics Breakthrough Award.[1][dead link]