Filter

With the knowledge that mangrove-mimicking membranes (Figure 3) have been developed, we plan to utilize them in a water desalination plant model. The filter would contain three parts: the sediment filter first, then the mechanical filter, followed by the mangrove-mimicking filter. The sediment filter, would take out the large particles, such as dirt, sand, small pieces of garbage, etc. The mechanical filter (Figure 2) would take out things as large as plankton, algae, and microplastics, and as small as viruses and large ions. The mangrove filter (Figure 3) is made up of the membrane discussed in the Background section. It would remove salt ions from saline water. This filtration system would also allow the device to operate in freshwater, where it could potentially remove contaminants.

The water would be pumped through the filters with centrifugal pumps (Figure 4), which work by rotating a set of vanes in the center of a sealed chamber filled with water. When these vanes rotate, the water is caused to rotate, and centrifugal force pushes it outward, where it is caught in the volute chamber. More water is then siphoned into the system, pushing the initial water out. The process repeats, and water is moved.

It is crucial that the head (friction) is lesser on the input end of the pump than that on the output end. If not, something called cavitation happens. Cavitation is a phenomenon where the pressure on the suction side of water dips below the pressure of the water. When this happens, the water begins to boil, causing vapor bubbles and damaging the pump (specifically the impeller, which is the part that holds the vanes, pictured in Figure 4).^[8] To prevent this, we put minimal amount of filtering before the pump, just enough to minimise wear on the pump, and all other filtering will happen afterward.