1) According to the UN Water at a global level, 80% of wastewater produced is discharged into the ecosystem untreated, causing widespread water pollution. Wastewater treatment is not only relevant to reduce environmental pollution but also to ensure drinking water supply, around 1.8 billion people use a contaminated source of drinking water. Even though there are numerous processes that can be used to clean up wastewaters depending on the type and extent of contamination, the most common barriers are the affordability of these technologies and their energy consumption.
2) Microbial Fuel Cells
Technology: A microbial fuel cell (MFC), is a bio-electrochemical system that drives an electric current by using bacteria and mimicking bacterial interactions found in nature. “The direct conversion of organic matter to electricity using bacteria” Logan. These electrochemical cells are constructed using either a bioanode and/or a biocathode. Inside the fuel cell, anaerobic bacteria releases electrons in an oxygen-free environment. The electrons flow to an anode and then into a circuit to cathodes in a separate chamber on the outside of the membrane.
Potential: MFCs use energy very efficiently than standard, in theory, an MFC is capable of energy efficiency far beyond 50%. Nonetheless, MFCs are only attractive for power generation applications that require only low power, therefore the amount of electricity generated will not compare will a power plant, or even cover the entire processing facility, but it can offset the energy used to clean the water. “The energy we don’t consume is more important than the electricity we might produce” Logan.
Constraints: The fuel cell is ideal for wastewater with a high concentration in organic material, mostly wastewater from agriculture and food processing rather than municipalities. This technology has had interesting advances in the proof of concept but it is still has a wide range of opportunity to increase processing volumes until it can be implemented at a large scale.
3) Municipal, industrial and agricultural water treatment facilities, will be able to increase the efficiency and reduce the sludge by applying this technology. Furthermore, this technology will enable small-scale decentralized water treatment facilities, owned by either farmers or communities.
4) The next steps to deploy this technology would be to increase processing volumes until it can be implemented at a large scale. Moreover, to evaluate the possibility to automatize the small-scale facilities to reduce operation and maintenance efforts to expand the user market.