A1. In fact, the fundamental solution to the problem of algae has been known for a very long time. Nevertheless, solving the green algae problem is not easy. The phenomenon of increasing the nitrogen and phosphorus concentration in water is called eutrophication. The most fundamental measure to prevent the formation of algae is to prevent nitrogen and phosphorus from entering the water. Then, the surest solution is to ensure that only nitrogen phosphorus in places such as sewage treatment plants and wastewater treatment plants is treated well. However, it is difficult to prevent eutrophication by itself because the discharged flow rate itself is so large.
In addition, even if nitrogen phosphorus emission is reduced to zero, most lakes and rivers have already accumulated nitrogen phosphorus in a high concentration at the bottom layer. If the wind blows strongly or the flow rate is a little high, the nitrogen phosphorus dissolved in the bottom layer may be supplied back into the water.
In the case of deep lakes, in the summer, the bottom becomes anaerobic and anaerobic, but the sediment is eluted again and the phosphorus concentration in the water increases. This will be repeated. Therefore, in fact, even if the inflow is completely blocked from the outside, in fact, a sufficient amount is already stored under the bottom of a lake or river, so it will take a very long time unless you remove it at the same time.
So, in addition to preventing the inflow of various nitrogen phosphorus, efforts are being made to develop a method to make it less produced when it actually occurs, or to collect and remove it quickly.
In summary, even if nitrogen from sewage or wastewater is reduced as much as possible, there is now a certain amount of nitrogen phosphorus in the bottom of the original ecosystem, so if conditions such as the water source and such flow rate are met, algal blooms through eutrophication can occur. Not only point sources such as sewage treatment plants, but also non-point sources must be well controlled.
A2. Actually, Korea now has an algae removal ship. It is a method of filtering water through a filter action and collecting and collecting only microalgae. In actual field, the number of ships is very insufficient compared to what occurs in the entire water body.
Also, the algae problem has been around for decades. Therefore, various methods for controlling this and quickly removing the generated algae have been developed and are not without effect.
However, there are common limitations. On a small scale, everything is fine. If a pond has algae, no matter what technology you use, you will probably be able to fix it quickly. However, if the area is large like the Nakdong River, it cannot be afforded in terms of efficiency or cost. This is the biggest problem.
Recently, there have been reports that a toxin called microcystin has been detected in tap water. In such a case that is directly related to public health, we will try to solve it no matter how expensive it is.
However, in Korea, there are many environmental issues besides algae, so unless it is directly related to the supply of drinking water, the algae problem cannot be a priority.
In addition, the following questions were asked:
We, KUAS, want to design a filter so that the annamox process can occur sequentially by binding the enzymes of the annamox microorganism to the membrane.
(1) Enzyme maintenance period and filter replacement method
(2) method of binding enzyme to membrane
(3) What kind of membrane to use
Considering the above, we asked for opinions on whether our idea would be feasible.
Finally, we also asked questions related to Dr. Chi-Yong Ahn's previously published thesis. According to that paper, it was said that there is an interaction between microorganisms in the occurrence of algae. In a module that increases or decreases at the same time at a specific time, controlling the occurrence of algae by removing or inhibiting microorganisms that play a key role in the increase of algae is the existing method. We asked and received answers about how effective it is than the method of removing or preventing algae.