Sparing the drain to power the neighborhood

Water is life. With the problem on global warming, scientists fear that the Earth’s water supply will run short. Aside from the issue on water shortage, there is a worldwide energy crisis.  Amidst these problems scientists at the Washington University in St. Louis are conducting a research on the possible use of wastewater to generate energy.
The Use of Wastewater
Scientists with the use of modern technology like digital binocular microscope are studying the use of a microbial fuel cell that can generate electricity from wastewater. Based on their scientific experiments, advances in the design of the fuel cell   have increased the power output by a factor of 10.  With future designs on their minds, scientists look forward to the possibility of increasing the power output by 10 times again. Should the system work, the fuel cell could be scaled up for use in various industries to generate electrical power.  The wastewater that just goes down the drain can be recycled into something significant.
How the System Works
Credit should be given to Lars Angenent, Ph.D., assistant professor of chemical engineering, and a member of the University’s Environmental Engineering Science Program. He conceived the idea of devising a continually fed up flow microbial fuel cell (UMFC). The wastewater enters from the bottom of a system where it is continually pumped up through a cylinder which is filled with granules of activated carbon. Other microbial experiments have utilized closed systems with a single batch of nutrient solution.   The UMFC is more advantageous.  It has more applications for industry since wastewater is continually outputted during industrial production.
As examined with the use of the digital binocular microscope the organic matter in the wastewater make available food for a diverse community of bacteria.  These bacteria have developed a biofilm or a thick-layered colony of bacteria on a simple electrode in the anode chamber. An economical U-shaped proton exchange membrane within the anode chamber divides the anode from the cathode.
A closer look at the bacteria under the digital binocular microscope shows that as they feed on the organic material in the wastewater they discharge electrons to the anodic electrode. The electrons then move to the cathodic electrode through a copper wire. The formed protons are then transferred through the membrane towards the cathode wherein they react with electrons and oxygen to form water.
The previous UMFC design used a cathode on top of the anode. The new design utilizes the U-shaped design.  The surface area was increased.  However, the distance between the anode and cathode was reduced.  The reduction helped minimize the power loss brought about by resistance. These two significant changes are largely responsible for the boost in power by a magnitude of 10 times from a maximum of 3 watts per cubic meter of solution in the previous study to a maximum of 29 w/m3 today. As what has been noted, sustained power in the system can average 20 watts per cubic meter which is enough to run a small light bulb.

Other Areas of Concern
The anode-cathode shapes, surface areas, as well as the distances to   both increase power and reduce the resistance in the system are being explored.
Scientists are likewise studying the economic viability level for the microbial fuel cell.  It is approximately 160 watts per cubic meter of solution.  The goal of increasing the power output by 10 times would increase the level to around 300. If this is feasible, the microbial fuel cell system would be a proof of concept with various applications in the food and agricultural industries. Inasmuch as this experiment utilizes wastewater which is abundant in industry, a scaleable adaptation of this system at a food industry could produce enough power supply for 900 American single-family households in the future.
A renewable energy source from wastewater is a major breakthrough.Read the entire article