For years, humans have been trying to find alternative sources of energy. Civil engineers have tried to find ways to have a cleaner environment, but at the same time, produce enough energy to make it practical. In the past, humans have relied heavily on fossil fuels (coal, gas and oil). More recently, scientists have experimented with cleaner sources of energy like solar, biofuels, and hydrogen-based energy. Early in the 21st century, civil engineers created a proof of concept of microbial fuel cell. These complex fuel cells mimic natural bacterial exchanges in nature and currents are created. The biggest hurdle civil engineers face is how to harvest the currents and how to convert them to energy. It is important to experiment with microbial fuel cells due to the fact that if scientists are able to magnify and collect the amount of electricity produced, the world will have a more reliable source of renewable energy cost effectively.
Today, microbial fuel cells are being used in breweries and wastewater treatment plants. In the case of breweries, the employees use microbial fuel cells to produce the energy that they need from their waste. This is more cost effective than coal or oil since the [fuel] cell runs off of the plant’s waste. A microbial fuel cell is a source of energy that harnesses bacteria to create electricity. In order for this reaction to start, there needs to be a catalyst between hydrogen and oxygen. A catalyst is a special material which facilitates a reaction between oxygen and hydrogen.
Microbial fuel cells use bacteria called exoelectrogens that can directly transfer electrons to a material or a chemical (the anode) that doesn’t normally accept electrons (Bruce E. Logan 12), to generate energy. The bacteria release electrons which are attracted to the anode because the anode is positively charged. This is important since, if these are scaled up to produce more power, they will be an effective source of clean energy. These bacteria only thrive in anaerobic conditions, or areas without oxygen. The bacteria break down the organic material for nutrients. As a byproduct of this reaction they produce electrons and CO2. This process is called anaerobic respiration or fermentation.
Basically a microbial fuel contains a cathode and an anode. The bacteria covered anode, or positively charged electrode, transfers the energy through a wire into the cathode, which completes the circuit since the cathode is negatively charged. Now, a problem with this is that the electrons will dissipate at some point, so to counteract that, a salt bridge is used to keep most of the electrons from dissipating on the cathode and the anode (Oldridge). This would be called a proton-exchange-membrane. A proton exchange membrane keeps the protons from dissipating out of the liquid and keeps both sides at a neutral charge by allowing ions to pass from the anaerobic chamber to the aerobic chamber (Rader). The aerobic chamber is aerobic since it contains...