Our team began tackling the issue of harmful algae by proposing a boat that physically cleans up the algae. We thought that it could essentially skim the algae off the top of the water and we would have a bioreactor that breaks down the toxins in the surface level water. We had this idea in mind because we knew that the majority of microcystin will be located within the first 1.6 meters of water. Past that depth, the concentration of microcystin drastically decreases, hence the remediation of lake water below this depth is not as important (González-Piana, pp. 614). We would use an Electro-coagulation-flotation(ECF) process to remove algae by designing a ECF reactor and attaching it to the bottom side of the boat.
Although this was a good starting point, there were 2 issues we discovered with this design:speed and battery capacity. To break down algae using the ECF process, we would have to slow down the boat drastically. At that rate, using a small remote controlled boat would take hundreds if not thousands of years to clean Cayuga lake. With the size of our battery, we would only be able to run the ECF reactor for 30 minutes at a time.
From this point, we began to brainstorm other ways we could accomplish our end goal of sampling and remediation. An autonomous way to sample water is not well developed in the scientific community and we opted to remove the microcystin, a greater danger than the algae itself. We decided as a team that having a boat to take samples quickly and having a separate bioreactor for water treatment plants where water could be pumped through at the correct speed would be more effective. With this two-part idea, we could detect the toxin as quickly as possible and then completely treat water (not just the surface) that is being distributed to the public.
After deciding on a separate boat and bioreactor, we had a complete plan for the boat, but needed new designs for the bioreactor. Weighing the pros and cons of various types of bioreactors for our specific project, we decided that a design resembling Gautier’s artificial liver reactor (Gautier 2011) would be ideal. We chose this idea because we needed a way for all of the water to interact with the bacteria while the bacteria remain enclosed for environmental safety. Pumping water through a tube of alginate beads would ensure both of these things. In addition, by manipulating how many beads, the nozzle, and speed of the pump, we would be able to ensure effective reactions, which gave us a lot more control than alternative designs such as a closed bioreactor where the water is held inside and mixed.
González-Piana, M., Piccardo, A., Ferrer, C., Brena, B., Pírez, M., Fabián, D., & Chalar, G. (2018). Effects of Wind Mixing in a Stratified Water Column on Toxic Cyanobacteria and Microcystin-LR Distribution in a Subtropical Reservoir. Bulletin of Environmental Contamination and Toxicology, 101(5), 611–616. doi: 10.1007/s00128-018-2446-x
Gautier, A., Carpentier, B., Dufresne, M., Vu Dinh, Q., Paullier, P., & Legallais, C. (2011). Impact of alginate type and bead diameter on mass transfers and the metabolic activities of encapsulated C3A cells in bioartificial liver applications. European Cells & Materials, 21, 94– 106.
Team:Cornell/DesignProcess
Design Process