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Wednesday, March 13, 2013

Microbial Fuel Cells For New Scientist And Investors

Many scientists and engineers begin their careers as young inventors, first building volcanoes or collecting insects for school science fairs, then moving on to more advanced studies and experiments that require more fundamental science and math foundations. At the heart of all these investigations is the desire to learn what makes things work and, if we are really lucky, to invent something new that will benefit mankind (and getting rich would be okay too!). Inventors can be young or old!. Continuing to invent throughout your life-thinking of new ideas and ways to improve existing designs-will keep you young and your mind agile.

Microbial Fuel Cells are a perfect platform for discovery, offering the inventor a chance to simultaneously delve into biology, chemistry, electronics, and physics. The choices that are made right from the start should reflect which of these aspects of design will be more exciting for you to focus on in your tests. Begin by asking questions about what things you will need to get started. Where will the inoculum come from, and what bacteria will develop?. What chemicals will be used for the solutions, and what materials for the system architecture will work best?. What does power really mean, and how much do you want to produce?. What materials are readily available and what will your design cost to build?. The cost will especially drive your design as you will probably want to make use of inexpensive materials that you can readily buy off the internet or from a local store. But don’t be discouraged by possible costs!. All engineers are challenged by the task of making something as good as possible, as quickly as possible, for as little money as possible (the so-called “better, faster, cheaper” motto).

As you make your choices and design your experiment, remember the scientific method: form a hypothesis, design an experiment to test that hypothesis, and then test it. Did you prove your hypothesis?. What else did you find out, and what new hypotheses will you investigate next?. Remember as you design your experiment that it is best to tackle only one aspect of design or operation at a time. While more advanced experimental design will allow you to test several variables (factorial experimental design), time constraints and your greatest understanding will result from varying only one thing at a time. Thus, if you look at effect of pH, vary only pH and not the inoculum and container and temperature. Keep a laboratory notebook, taking careful notes especially when you change something in your experimental procedure that might affect your results later on. Take lots of pictures so you have a record of what something looked like in past experiments-and so you have some nice pictures for that science fair poster!, Use safe laboratory practices, like wearing safety goggles and gloves.
generalized schematic of microbial fuel cell reactor
Generalized Schematic of Microbial Fuel Cells Reactor
While it is unlikely that you will electrocute yourself (or even be able to feel the slight current generated by a homemade Microbial Fuel Cells), you will be growing bacteria and you never know what kind of bacteria will grow there. Even if you wear gloves, be sure to wash your hands and other materials. Treat your Microbial Fuel Cells reactor waste like you would a baby’s diaper-best to be moved quickly outside and to a suitable waste container. Also note that some science fairs have strict rules when it comes to handling bacteria. For example, the INTEL International Science and Engineering fair they have strict rules for all “projects involving microorganisms, recombinant DNA technologies and human or animal fresh tissues, blood or body fluids.” They have two allowed classes of treatment, BSL-I and BSL-2, with two higher classes of research that are prohibited due to safety concerns. They consider “the culturing of human or animal waste, including sewage sludge” as a BSL-2 study, requiring their strictest safety protocols. There are requirements for safe disposal of wastes, which includes autoclaving at 121°C for 20 minutes, disinfection with 10% sodium hypochlorite or alkaline hydrolysis, incineration, or biosafety pick-up. Be sure to read the rules, as you would likely be disqualified from the competition.