Preliminary Design Considerations

Bioreactor Design Considerations

Over the summer, much thought was put into the design of our bioreactor in order to optimize functionality, expense, and safety. Although many of the details of our design cannot be worked out due to the time constraint of a four-month period, there are still lots of theoretical aspects that we were able to cover. The first aspect of our design was choosing what type of bioreactor system to use. For lab scale experiments and design, we chose to use a system that is closest to that of a batch system. This system requires all reactants to be added at time zero, with everything being removed at once when the remediation has come to completion. However, our design uses a belt skimmer to continually remove any products (hydrocarbons) formed either emulsified or found on the top layer. This way, we are able to reuse our culture and remove product until all the naphthenic acids are converted. We then remove everything in the tank and begin the process again. Our skimmed product goes through UV radiation in order to kill any bacteria that happen to be left in the product. In addition, our bioreactor bacteria will contain kill genes. When our bacteria are in a glucose-free environment (a.k.a. outside the tank) the bacteria are programmed to self-destruct. Since we have three different intermediate steps for remediation (desulphurization, denitrification, decarboxylation). With this being said, we will need three tanks with the product from the previous tank acting as the reactant for the next tank in line. The product of the last tank will go through distillation to purify our desired alkane. To improve the growth and environment of our bacteria, we will keep our bioreactor at ideal growth temperature (if E coli, 37 degreees; if pseudomonas 25 degrees). In addition, we will have an agitator (turbine) and air sparger to help mix and oxygenate our solution.