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 | edit source]
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.
Notes[edit | edit source]
- 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?[expansion needed]
- 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.[dead link]