The effect of floating plant on water purification: Comparison of the water purification capability of Water Hyacinth, Duckweed, and Azolla

Water pollution is a critical issue for human health, aquatic plant and animal biodiversity. While there are several different approaches to resolve this issue, our research investigates one possible solution of using aquatic plants as a natural treatment system. To identify the optimal plant for treating polluted water in India, we selected water from the Mithi river and three types of floating plants: water hyacinth (Eichhornia crassipes), duckweed (Lemna perpusilla), and azolla (Azolla pinnata). We used a total of six measurements (dissolved oxygen, conductivity, turbidity, pH, color of water, and the number of colonies grown on the culture media) taken for seven days to compare the effect of each floating plant on the change in water quality. We hypothesized that duckweed would be the best plant to purify water in India since its effect on reducing turbidity or biochemical oxygen demand (BOD) was found in past research.
Our results show that all three floating plants are effective at purifying the water. Further, duckweed significantly reduced the turbidity and number of bacteria in the water, suggesting it may be the most optimal water purifier among those three. Based on the results from this experiment, we recommend floating plants as one alternative to resolving water pollution in India, which would effectively purify water as well as require less cost for construction and maintenance.