Electricity from waste water

Electricity can be produced from waste water using microbial Fuel Cell (MFC). It can turn the organic wastes into a source of electricity.
Fuel cell

A fuel cell is an electrochemical energy conversion device that converts the chemical energy from fuel (on the anode side) and oxidant (on the cathode side) directly into electricity. There are many types of fuel cells, depending on what kind of fuel, electrolyte and oxidant they employ. Fuel cells use hydrogen gas which is produced from fossil fuels.
Microbial Fuel Cell

Microbial Fuel Cell makes the treatment of organic pollutants a direct producer of electricity, not a consumer. Further it expands fuel-cell technology to use renewable organic materials as a fuel; the MFC can use organic fuels that are wet, the usual form for wastes and fuel crops. The MFC, by operating at ambient temperature, can double to triple the electricity-capture efficiency over combustion, while eliminating all the air pollution that comes from combustion.

Mechanism

MFCs function on different carbohydrates but also on complex substrates present in wastewaters. As yet there is limited information available about the energy metabolism and nature of the bacteria using the anode as electron acceptor; few electron transfer mechanisms have been established unequivocally. Nonetheless, the efficient electron transfer between the microorganism and the anode (e.g., microorganisms forming a biofilm on graphite fibers) seems to play a major role in the performance of the fuel cell.