This project was motivated by reading an article about the current green algae problem in Korea (which has recently been intensifying). As it has a huge impact on odors and aesthetics, as well as aquaculture, drinking and agricultural procurement, the algae issue is not limited to Korea, but is more likely to be a global-level problem.
We learned that microcystin, a toxic substance produced by green algae, was detected in tap water in Korea. South Korea has world-class water purification technology, so we couldn't believe it. In addition, microcysitin has negative effects not only on humans but also on aquatic ecosystems, so we felt it require research approach in this point.
The four main factors that cause algae can be summarized as follows:
(1) Nutrients such as nitrogen and phosphorus
(2) High water temperature
(3) Strong sunlight (Insolation)
(4) Residence time
The main cause of algae is excessive use of nitrogen-phosphorus-potassium fertilizers. Nitrogen and phosphorus remaining due to excessive use of fertilizers flow into rivers through agricultural waterways, which was found to be the main culprit of eutrophication, the cause of green algae. Unlike the point source facilities such as drinking water treatment plants and sewage treatment plants, agricultural waterways, (which are non-point sources of pollution) are highly likely to be exposed to the risk of algae and eutrophication.
In this context, we focused on the vicious cycle in which Nitrogen and Phosphorus inflow into rivers due to excessive use of fertilizers causes algae, and the rivers in which the algae proliferate are reused for agricultural water. Therefore, our team decided to develop a Nitrogen treatment Bio Filter that can be easily installed and used by general farmers in private agricultural waterways.
Among Phosphorus and Nitrogen, Nitrogen was chosen for the following reasons: Phosphorus is a substance with a high possibility of causing various side effects by contributing to the phosphorylation process of various organisms. As it is a filter that is installed directly in the ecosystem, we tried to minimize the effect of the product of the metabolic process using Phosphorus on living things in other aquatic environments.
We have come up with several ways to solve the algae problem:
There are three main ways to attach an enzyme to a filter. A method of physically attaching, a method of attaching using a covalent bond, and a method of capturing enzymes using a porous membrane. When we attach the enzyme to the filter, we need to consider 'Is it easy to attach', 'Is there permeability in the filter as metabolites must be transferred between the enzymes attached to the filter', 'Is the enzyme attached to the filter and the filter itself can it withstand the current of water?'. As a result of considering the above, our team adopted a method of capturing enzymes in a porous membrane. By using a special porous membrane, a large number of enzymes can be easily attached, and water can make contact with the enzyme as it passes through the membrane, making the desired process better.