해수 담수화: 해수 담수화: 이점 및 환경적 과제

해수 담수화는 물 부족에 대한 희망을 제시하지만, 시급히 해결해야 할 환경 문제를 야기합니다.

### 해수 담수화의 씁쓸한 진실: 해수 담수화의 장점과 환경적 과제
* 💧 지구상에 존재하는 물의 양은 엄청나게 많지만, 염분이 많은 바닷물과 얼어붙은 물이 대부분이기 때문에 **마실 수 있는 물은 1% 정도**에 불과합니다.
* 🌍 지도에서 빨간색으로 표시된 지역은 **연중 물 부족**으로 어려움을 겪는 지역을 나타내며, 물의 풍요로움과 접근성의 역설을 강조합니다.
* 🌡 많은 사람들이 지구 온난화로 인해 강우량이 증가할 것이라고 생각하지만, 기후 변화는 실제로 많은 지역에서 **건조를 악화**시켜 물 부족이 증가할 것으로 예상됩니다.
* 🔬 담수화는 고대 방식에서 증발 및 역삼투압과 같은 현대 기술로 발전하면서 수세기 동안 해결책을 제시해 왔으며, 현재 전 세계적으로 **16,000개 이상의 플랜트**가 운영되고 있습니다.
* 🌊 그러나 담수화 과정에서는 특히 바닷물을 끓이는 데 사용되는 화석 연료로 인해 **상당한 온실가스**가 발생하여 환경에 미치는 영향에 대한 우려가 제기되고 있습니다.
* ☀ 사우디아라비아의 솔라 돔과 같은 혁신적인 프로젝트는 **담수화에 태양 에너지를 활용하여 비용 효율적인 비율로 탄소 배출이 전혀 없는 담수를 생산**하는 것을 목표로 합니다.
* 담수화 과정에서 생성되는 농축된 염수는 해양 생태계에 심각한 위협이 되고 있으며, 많은 시설에서 **적절한 규제 없이 이를 다시 바다로 배출**하고 있습니다.
* 🔍 이러한 문제를 해결하기 위해 지속적인 연구를 통해 **염수 염도를 낮추고 귀중한 미네랄을 회수하는 방법**을 모색하고 있지만, 이러한 솔루션의 광범위한 채택은 미래의 목표로 남아 있습니다.

Oh, amazing! Wow, it's incredible! But there is one thing that both you and I know: behind something sweet, flashy, and grand, there is a bitterness that we either do not know or choose to ignore. Today, I want to talk about the somewhat uncomfortable truth regarding seawater and freshwater. The areas that appear in bright red on the map are regions that suffer from water scarcity all year round. Of course, no one looking at these areas would say, Hey, there’s water all around; why is there a shortage? That’s understandable because 70% of the Earth's surface is covered in water, totaling about 1.3 billion cubic kilometers. However, a staggering 97% of that is salty seawater, which is difficult to drink, and most of the remaining 3% is frozen. In the end, we can only use about 1% of the Earth's water as drinking water. Given this situation, countries that are inherently water-scarce due to their geographical location inevitably suffer from a shortage of drinking water.

There are some people who believe that global warming is making the Earth hotter, causing seawater to evaporate and resulting in more rainfall, thus solving the drinking water problem. However, this is a one-dimensional way of thinking. The climate changes caused by global warming make dry areas even drier, and the large amounts of rain clouds brought about by warming are likely to pour rain only in specific regions at specific times. Therefore, scientists predict that the current climate change will accelerate water scarcity. But as you know, there is a really simple solution: widely desalinating seawater makes the game over. In fact, this method has been used since thousands of years ago. Ancient Greek sailors boiled seawater on their ships and used the condensed water as drinking water, while in ancient Rome, they used clay filters to turn seawater into freshwater. And now, in modern times, we have more advanced methods.

The principles have become more sophisticated and large-scale, but they remain the same. The evaporation method, which cools the steam generated by boiling seawater to create fresh water, and the reverse osmosis method, which filters out salt by passing seawater through a semi-permeable membrane under high pressure, are representative examples. As we can see in this graph, starting in the late 20th century, the number of plants has increased exponentially as the costs of seawater desalination technology have decreased. Currently, there are over 16,000 plants operating in 77 countries around the world. Of course, there are also plants in our country, and above all, Korea is well-known as an exporter of this technology. However, it is important not to misunderstand that just by looking at this number, it may seem like seawater desalination technology is widespread globally. As we can see, most of the installed plants are concentrated in high-income countries such as the Middle East, Europe, and North America. Anyway, the seawater desalination plants installed around the world...

The amount of freshwater produced in desalination plants in a single day reaches an astonishing 100 billion liters. Particularly in Saudi Arabia, a country with no rivers at all, most of the drinking and agricultural water relies on seawater desalination, accounting for one-fifth of the world's freshwater. However, with ongoing projects like The Line, a massive 170 km long linear city that Saudi Arabia is planning, the demand for desalination plants will significantly increase to supply drinking water. Of course, this issue is not limited to Saudi Arabia alone. However, the increase in seawater desalination plants poses a significant problem: the generation of greenhouse gases. As mentioned earlier, the evaporation method of seawater desalination literally involves boiling seawater, which requires a corresponding amount of fossil fuels to be burned to heat vast quantities of water.

the enormous amount of greenhouse gases is generated in the process. Isn't that ironic? Many scientists are searching for solutions, and one of them is solar energy. The Solar Dome project currently underway in Saudi Arabia involves placing a large dome in the middle of the desert, surrounded by mirrors. Seawater is drawn into the dome and stored, and then the light reflected by the mirrors is used to heat the stored seawater, resulting in zero carbon emissions. Additionally, the eco-friendly seawater desalination project installs solar panels in small-scale desalination facilities, where the electricity generated is used to produce fresh water. This project is highly cost-effective, producing fresh water at about 700 won for 1,000 liters. As a result, this technology is already being adopted in some villages in developing countries. However, there is a fundamental issue with seawater desalination technology that is difficult to overcome even with renewable energy.

There is still the issue of concentrated brine. Many people focus on the freshwater produced through various processes of seawater desalination. However, have you ever thought about what happens to this highly concentrated saltwater? Unfortunately, most of it is simply dumped back into the ocean. For example, in the case of reverse osmosis, when 2 liters of seawater are passed through a semi-permeable membrane, the amount converted into freshwater is about 1 liter, which is roughly 50%, while the remaining 1 liter becomes concentrated brine, most of which is released back into the sea. A report written by the Korean Environment Policy Evaluation Institute in 2018 points out this problem. In the United States alone, 48% of seawater desalination facilities discharge concentrated brine directly into the ocean. Particularly, the concentrated brine in high-temperature and high-salinity conditions poses a problem in itself, but water with high salinity also has a low capacity for dissolved oxygen.

If concentrated water flows into the sea, there is a growing concern that it could destroy marine ecosystems. In fact, experiments that exposed marine organisms to high concentrations of concentrated water showed that the species richness of fundamental organisms in the ecosystem, such as phytoplankton and seaweed, significantly decreased. Moreover, there were cases of mortality in fish like flounder, as well as reduced growth rates, lower reproductive rates, and diminished ink defense abilities in cephalopods like squid. It was confirmed that the survival and reproduction rates of shellfish, such as oysters and clams, decreased when exposed to concentrated water. However, the bigger problem is that despite this situation, it is very rare for the discharge status of concentrated water to be made public. Except for some regions like the United States, Australia, and Japan, the reality is that most places have minimal standards or regulations regarding the discharge of concentrated water.

Ultimately, even if we solve the greenhouse gas problem with renewable energy technology, if the technology and regulations regarding brine treatment are not properly established, seawater desalination technology will struggle to gain acceptance. However, as always, scientists are once again searching for answers. There are simple methods, such as mixing wastewater from nearby sewage treatment plants with brine to lower salinity before discharging it further away. Recently, research has been underway to efficiently extract useful minerals like lithium and magnesium from brine. There is also research on energy recovery technology that involves installing a semi-permeable membrane between highly concentrated brine and fresh water, generating electrical energy from the osmotic pressure that occurs there. However, most of these studies are still in the early stages, and it is expected to take time for them to become widespread. Personally, I believe that seawater desalination is a technology that is essential for the era of the iPhone.

There are disadvantages such as the occurrence of real-time costs and concentrated water, but when you think about it, is there any technology developed by humanity that has no drawbacks? However, I believe that when innovative technologies are introduced to a large audience, the underlying disadvantages must be adequately mentioned. There is a clear difference between society knowing about these issues and accepting the technology versus being unaware and accepting it. Science is a window to see the world. This has been Science Dream. Thank you.

해수담수화 기술은 정말 물 부족 위기의 해결사일까?(ft.비용이 문제가 아냐!)

과학으로 재미와 지식을 더해 드리는 채널입니다.
한 때는 과학을 좋아했던, 지금도 과학을 좋아하는, 
그리고 앞으로 과학을 좋아할 사람들이 제 채널과 함께였으면 합니다.
문의: sciencegive@gmail.com

과학드림 [Science Dream]

지구의 70%가 물로 덮여 있음에도 불구하고 지도에서 빨간색으로 표시된 지역은 물 부족에 시달리고 있습니다.

짠 바닷물은 지구 물의 97%를 차지하며, 식수로 사용할 수 있는 물은 1%에 불과합니다.

지구 온난화가 강우량에 미치는 영향은 복잡하고 잠재적으로 물 부족을 악화시킬 수 있지만, 해수 담수화는 역사적이고 현대적인 해결책을 제시합니다.

해수 담수화가 전 세계에 미치는 영향

증발 및 역삼투압과 같은 해수 담수화 방식은 더욱 정교해지고 널리 보급되어 77개국에서 16,000개 이상의 플랜트가 운영되고 있습니다.

이 기술의 성장은 중동, 유럽, 북미와 같은 고소득 국가에서 대부분의 플랜트를 운영하면서 비용 감소에 힘입어 이루어지고 있습니다.

담수화는 상당한 양의 담수를 공급하지만, 이 과정에서 사용되는 화석 연료로 인해 온실가스 배출에 대한 우려도 제기되고 있습니다.

해수 담수화에서 태양 에너지의 역할

사우디아라비아의 솔라 돔 프로젝트는 거울을 이용해 저장된 바닷물을 가열하여 탄소 배출을 제로로 만드는 것을 목표로 합니다.

이 친환경 담수화 프로젝트는 1,000리터에 700원으로 담수를 생산할 수 있어 비용 효율적이어서 개발도상국에서 채택하고 있습니다.

하지만 담수화 과정에서 발생하는 농축된 염수가 다시 바다로 버려지는 경우가 많아 환경 문제가 심각합니다.

농축수 배출이 해양 생태계에 미치는 영향

바다로 유입되는 농축수는 해양 생태계를 해치고 있으며, 어류와 두족류와 같은 주요 생물의 종 다양성과 사망률을 감소시키고 있습니다.

농축수의 배출은 대부분의 지역에서 최소한의 규제만 있을 뿐 공개적으로 공개되지 않는 경우가 많습니다.

과학자들은 폐수를 소금물과 섞어 유용한 미네랄을 추출하는 등 그 영향을 완화하는 방법을 모색하고 있지만 아직 초기 단계에 머물러 있습니다.

혁신적인 기술에는 실시간 비용과 리소스 집중 사용과 같은 단점이 있는 경우가 많습니다.

많은 사람들에게 새로운 기술을 소개할 때는 이러한 단점을 적절히 언급하는 것이 중요합니다.

이러한 문제에 대한 사회의 인식은 기술을 받아들이는 데 중요한 역할을 합니다.