Biofilm: The Miracle
Danlu Liu, Laura Chen
R C Palmer Secondary
Floor Location : M 220 V

We wanted to see if there is a way to prevent soil liquefaction in the event of an earthquake using biofilm. The earthquake in Haiti (2010) and Japan Earthquake (2011), as well as many other devastating calamities inspired us to pursue this project. Soil liquefaction is when the soil changes from a solid state to a liquid one due to stress and water saturation, and causes destruction of buildings and loss of lives. This piqued our interest because biofilm is naturally found in nature, so there is no need to manufacture synthetic chemicals, which would probably be detrimental to the environment. Thus we decided to test the results of the solidification with 2 different types of biofilm and compare both along with the control (no biofilm added).rnrnSo, how was this experiment conducted? In the most concise form, two different types of biofilm are cultured in Petri dishes, and then tested against the control in two different aspects: density and reaction during a simulated earthquake. The two types of biofilm that we cultured are plaque, and the biofilm found in water pipes, Pseudomonas aeruginosa. Each is left aside for a week to grow, and then mixed into a fixed amount of sand with a small, fixed amount of water. Then they are set aside in the same location for one more week to allow the biofilm to multiply. The mass is measured both before and after the time span of a week. After that period of time, the biofilm is mixed into the water and set aside for another week, after which the mass is measured again and the density calculated. After that, the sand is put into a mini loaf pan, had water added to it, and banged with a metal rod at a set speed to simulate and earthquake and observe the effects of liquefaction.rnOur hypothesis was proven to be true from the data collected. The density of the plaque was higher than the kitchen sink biofilm. In short, our hypothesis was supported by our data because the biofilm did help to solidify the sand and the plaque worked the best out of the two types. We believe that is because the plaque is more viscous and has a faster growth rate. rnrnNow, the purpose of this experiment was to see if we can prevent soil liquefaction using natural methods (biofilm). Since the experiment showed that it actually is feasible, one can try to build a prototype that can pump the biofilm into the soil. This could then be used in areas like Richmond, which is on the Ring of Fire (earthquake hotspot), and is susceptible to liquefaction. With this in place, we can prevent, or lessen the effects of soil liquefaction in the event of an earthquake. That is the entire purpose of this investigation. However, further testing will need to be done to see if this is effective on a large scale.