演講MP3+雙語文稿:保持河流清潔的鹽循環(huán)經(jīng)濟

聽力課堂TED音頻欄目主要包括TED演講的音頻MP3及中英雙語文稿，供各位英語愛好者學習使用。本文主要內(nèi)容為演講MP3+雙語文稿:保持河流清潔的鹽循環(huán)經(jīng)濟，希望你會喜歡！

【演講者及介紹】Tina Arrowood

通過將科學、循環(huán)思維和顛覆性創(chuàng)新結合起來，蒂娜·阿羅伍德幫助人們設想了一個淡水不稀缺，而是管理良好的世界。

【演講主題】保持河流清潔的鹽循環(huán)經(jīng)濟

A circular economy for salt that keeps rivers clean

【中英文字幕】

翻譯者 Yanyan Hong 校對者 Yolanda Zhang

00:13

Growing up in northern Wisconsin, I've naturally developed a connection to the Mississippi River. When I was little, my sister and I would have contests to see who could spell "M-i-s-s-i-s-s-i-p-p-i" the fastest. When I was in elementary school, I got to learn about the early explorers and their expeditions, Marquette and Joliet, and how they used the Great Lakes and the Mississippi River and its tributaries to discover the Midwest, and to map a trade route to the Gulf of Mexico. In graduate school, I was fortunate to have the Mississippi River outside my research laboratory window at the University of Minnesota. During that five-year period, I got to know the Mississippi River. I got to know its temperamental nature and where it would flood its banks at one moment, and then shortly thereafter, you would see its dry shorelines.

我在威斯康星州北部長大， 很自然地與密西西比河 產(chǎn)生了親密的連結。 小時候， 我會和姐姐比賽誰能最先拼寫出 “M-i-s-s-i-s-s-i-p-p-i（密西西比）”。 上小學時， 我學到了早期的探險家 以及他們的冒險， 馬奎特和朱莉特，以及他們是 如何通過五大湖，密西西比河 及其支流，發(fā)現(xiàn)了美國中西部， 并將到墨西哥灣的貿(mào)易路線畫成了地圖。 在讀研究生時， 我很幸運，密西西比河正好 就在我所在的明尼蘇達大學 研究實驗室窗外。 在那五年期間， 我有機會認識了密西西比河， 我發(fā)掘了它無與倫比的特質(zhì)， 可能某一刻它會將河岸淹沒， 不久后， 干燥的河岸線又清晰可見了。

01:10

Today, as a physical organic chemist, I'm committed to use my training to help protect rivers, like the Mississippi, from excessive salt that can come from human activity. Because, you know, salt is something that can contaminate freshwater rivers. And freshwater rivers, they have only salt levels of .05 percent. And at this level, it's safe to drink. But the majority of the water on our planet is housed in our oceans, and ocean water has a salinity level of more than three percent. And if you drank that, you'd be sick very quick. So, if we are to compare the relative volume of ocean water to that of the river water that's on our planet, and let's say we are able to put the ocean water into an Olympic-size swimming pool, then our planet's river water would fit in a one-gallon jug. So you can see it's a precious resource.

今天，作為一位物理有機化學家， 我致力于利用我所學， 來保護像密西西比河這樣的河流， 避免因為人類的活動， 而造成河流鹽分升高。 因為 鹽分會污染淡水河流。 淡水河流的鹽分含量只有 0.05 %， 鹽分在這個范圍內(nèi)的水可以安全飲用。 但地球上大部分的水來自我們的海洋， 而海洋的鹽含量超過 3%， 如果飲用海水，你很快就會生病。 所以若要將地球上所有的海水 和河流水量相比較， 假設我們把海水放進 奧運標準游泳池中， 那么地球上的河流水量 就相當于一加侖。 所以不難想到， 這是彌足珍貴的資源。

02:12

But do we treat it like a precious resource? Or rather, do we treat it like that old rug that you put in your front doorway and wipe your feet off on it? Treating rivers like that old rug has severe consequences. Let's take a look. Let's see what just one teaspoon of salt can do. If we add one teaspoon of salt to this Olympic-size swimming pool of ocean water, the ocean water stays ocean water. But if we add that same one teaspoon of salt to this one-gallon jug of fresh river water, suddenly, it becomes too salty to drink. So the point here is, because rivers, the volume is so small compared to the oceans, it is especially vulnerable to human activity, and we need to take care to protect them.

可是我們有把它當作 珍貴的資源來對待嗎？ 或者，我們對待它的方式， 就像對待鋪在大門口的 老式地毯，頂多用來擦擦鞋？ 把河流當作老地毯會導致嚴重的后果， 我們來看看。 我們來看看一茶勺的 鹽會有什么影響， 如果我們在一個裝滿 海水的奧運會標準泳池中 加入一勺鹽， 海水依然是海水， 但是再加進同樣一茶勺的鹽 到一加侖干凈河水中， 一下子整罐水就因太咸而無法飲用。 重點是因為， 相比海洋，河流的水太稀少了， 它很容易受到人類活動的影響， 而我們需要小心地保護河流。

03:02

So recently, I surveyed the literature to look at the river health around the world. And I fully expected to see ailing river health in regions of water scarcity and heavy industrial development. And I saw that in northern China and in India. But I was surprised when I read a 2018 article where there's 232 river-sampling sites sampled across the United States. And of those sites, 37 percent had increasing salinity levels. What was more surprising is that the ones with the highest increases were found on the east part of the United States, and not the arid southwest. The authors of this paper postulate that this could be due to using salt to deice roads. Potentially, another source of this salt could come from salty industrial wastewaters.

最近，我通過調(diào)查文獻， 了解了全世界各地的河流健康問題， 我完全預期會在水源稀少， 以及重度工業(yè)發(fā)展區(qū)看到“生病”的河流。 我的確在中國北部和印度看到了。 但讓我意外的是， 在一篇 2018 年最新的文章中， 提到在全美有 232 個河流抽樣站點， 對美國各地河流抽樣， 這些站點顯示， 在 37% 的地方發(fā)現(xiàn)鹽度超標。 更讓人驚訝的是， 鹽度增加最多的站點 在美國東部， 而不是干旱的西南部。 這篇文章的作者推測， 原因可能是因為當?shù)厥褂?鹽來應對道路結冰問題， 另一個可能來源是 含鹽的工業(yè)廢水。

04:02

So as you see, human activities can convert our freshwater rivers into water that's more like our oceans. So we need to act and do something before it's too late. And I have a proposal.

如你所見，人類的活動 可能讓干凈的河流變成 更像是海水的水。 所以我們必須盡快行動起來。 我有一項提議。

04:17

We can take a three-step river-defense mechanism, and if industrial-water users practice this defense mechanism, we can put our rivers in a much safer position. This involves, number one, extracting less water from our rivers by implementing water recycle and reuse operations. Number two, we need to take the salt out of these salty industrial wastewaters and recover it and reuse it for other purposes. And number three, we need to convert salt consumers, who currently source our salt from mines into salt consumers that source our salt from recycled salt sources. This three-part defense mechanism is already in play. This is what northern China and India are implementing to help to rehabilitate the rivers. But the proposal here is to use this defense mechanism to protect our rivers, so we don't need to rehabilitate them. And the good news is, we have technology that can do this. It's with membranes.

我們可以采取一個 三步計劃預防河流污染， 如果工業(yè)水的排放者 能采取這個預防步驟， 我們就可以讓河流更安全。 此內(nèi)容包括，第一， 導入水回收和再利用的方法， 從而減少河流取水。 第二， 我們必須將鹽分 從工業(yè)水中提取出來， 再利用到其他地方。 第三，我們要將目前 使用巖鹽的消費者轉變成 使用回收鹽的消費者。 這三個步驟的處理方法已在實施， 中國北部和印度正在 采用這一機制來補救河流。 但我提出的意見是， 要用這個預防機制 來保護我們的河流， 這樣就不需要事后再補救。 好消息是，我們可以使用薄膜技術 來實現(xiàn)。

05:26

Membranes that can separate salt and water. Membranes have been around for a number of years, and they're based on polymeric materials that separate based on size, or they can separate based on charge. The membranes that are used to separate salt and water typically separate based on charge. And these membranes are negatively charged, and help to repel the negatively charged chloride ions that are in that dissolved salt. So, as I said, these membranes have been around for a number of years, and currently, they are purifying 25 million gallons of water every minute. Even more than that, actually. But they can do more.

這種薄膜可以把鹽和水分離開。 薄膜在很多年前就已存在， 采用的是聚合材料， 依據(jù)體積來進行物質(zhì)分離， 也可以依據(jù)電荷來做分離。 用來將鹽和水分離的薄膜， 通常是根據(jù)電荷來做分離。 這些薄膜本身帶有負電荷， 能協(xié)助排斥溶解鹽中 帶負電荷的氯離子。 我剛才提到，這些薄膜 在很多年前就有了， 目前，它們每分鐘能 凈化兩千五百萬加侖的水。 甚至更多。 但是它們能做的遠不只這些。

06:13

These membranes are based under the principle of reverse osmosis. Now osmosis is this natural process that happens in our bodies -- you know, how our cells work. And osmosis is where you have two chambers that separate two levels of salt concentration. One with low salt concentration and one with high salt concentration. And separating the two chambers is the semipermeable membrane. And under the natural osmosis process, what happens is the water naturally transports across that membrane from the area of low salt concentration to the area of high salt concentration, until an equilibrium is met.

這些薄膜是以滲透原理為基礎的。 滲透是我們身體中 會發(fā)生的自然過程—— 和細胞的工作原理有關。 滲透作用就是有兩個不同的空間， 將兩種不同濃度的鹽溶液分開， 一份是低鹽度， 另一份是高鹽度。 將兩個空間隔開的是 一張半滲透性的薄膜。 在自然滲透的過程中， 水會很自然的通過薄膜， 從低鹽份濃度的地方 流動到高鹽度濃度的地方， 直到兩邊的濃度達到平衡。

06:55

Now reverse osmosis, it's the reverse of this natural process. And in order to achieve this reversal, what we do is we apply a pressure to the high-concentration side and in doing so, we drive the water the opposite direction. And so the high-concentration side becomes more salty, more concentrated, and the low-concentration side becomes your purified water. So using reverse osmosis, we can take an industrial wastewater and convert up to 95 percent of it into pure water, leaving only five percent as this concentrated salty mixture. Now, this five percent concentrated salty mixture is not waste. So scientists have also developed membranes that are modified to allow some salts to pass through and not others. Using these membranes, which are commonly referred to as nanofiltration membranes, now this five percent concentrated salty solution can be converted into a purified salt solution. So, in total, using reverse osmosis and nanofiltration membranes, we can convert industrial wastewater into a resource of both water and salt. And in doing so, achieve pillars one and two of this river-defense mechanism.

逆滲透作用則是逆轉這個過程。 為了實現(xiàn)逆轉， 我們就要施加壓力 給高濃度的那一端， 這么做就能讓水往反方向流動。 高濃度的那一端含鹽量會增加， 濃度更高， 而低濃度那一端 則會變成凈化過的水。 利用逆滲透方法， 我們可以把 95% 的工業(yè)用水轉化為干凈的水， 只留下 5% 高濃度的鹽混合物。 而這 5% 高鹽濃度的混合物 并非廢物。 科學家也研發(fā)出了改造過的薄膜， 讓某些鹽可以通過， 而其他的不行。 使用這些薄膜， 也就是我們熟知的納米過濾膜， 這 5% 的高濃度溶液， 就能被轉化成純鹽溶液， 所以，總的來說， 有了逆滲透技術和納米薄膜， 我們就能把工業(yè)廢水 轉化成水和鹽， 這樣一來， 就能實現(xiàn)河流保護機制 的第一和第二步。

08:18

Now, I've introduced this to a number of industrial-water users, and the common response is, "Yeah, but who is going to use my salt?" So that's why pillar number three is so important. We need to transform folks that are using mine salt into consumers of recycled salt. So who are these salt consumers? Well, in 2018 in the United States, I learned that 43 percent of the salt consumed in the US was used for road salt deicing purposes. Thirty-nine percent was used by the chemical industry.

我曾向一些工業(yè)水 使用者介紹了這個機制， 通常得到的反饋是， “不錯啊，但是誰會要我的鹽呢？” 這就是為什么第三步很關鍵， 我們必須要將使用巖鹽的消費者， 轉化為使用回收鹽的消費者， 那么這些消費者是誰呢？ 2018 年， 我發(fā)現(xiàn)美國消費鹽的人當中 43% 都是把鹽用在防止道路結冰上。 39% 是化學工業(yè)在使用。

08:56

So let's take a look at these two applications. So, I was shocked. In the 2018-2019 winter season, one million tons of salt was applied to the roads in the state of Pennsylvania. One million tons of salt is enough to fill two-thirds of an Empire State Building. That's one million tons of salt mined from the earth, applied to our roads, and then it washes off into the environment and into our rivers. So the proposal here is that we could at least source that salt from a salty industrial wastewater, and prevent that from going into our rivers, and rather use that to apply to our roads. So at least when the melt happens in the springtime and you have this high-salinity runoff, the rivers are at least in a better position to defend themselves against that.

我們來看看這兩種應用。 我很震驚， 在 2018 年到 2019 年冬季， 一百萬噸的鹽被用在 賓夕法尼亞州的道路上。 一百萬噸的鹽足以 裝滿三分之二的帝國大廈。 也就是說從地球上 開采出了一百萬噸的鹽， 用于我們的道路， 接著這些鹽就 被沖刷進了我們的河流。 所以我的提議是，至少我們可以 從含鹽的工業(yè)廢水中提取那些鹽， 避免這些鹽進入我們的河流， 把它們使用在我們的道路上。 這樣至少在春季融冰之時， 出現(xiàn)高鹽度的徑流時， 我們的河流狀況會更好， 可以有強的抵抗能力。

09:54

Now, as a chemist, the opportunity though that I'm more psyched about is the concept of introducing circular salt into the chemical industry. And the chlor-alkali industry is perfect. Chlor-alkali industry is the source of epoxies, it's the source of urethanes and solvents and a lot of useful products that we use in our everyday lives. And it uses sodium chloride salt as its key feed stack. So the idea here is, well, first of all, let's look at linear economy.

身為一名化學家， 更讓我激動的機會是 把循環(huán)鹽導入化學工業(yè)這個概念。 氯堿工業(yè)是個理想的對象， 它是環(huán)氧樹脂的來源， 也是聚氨酯和各種溶劑， 以及我們?nèi)粘Ｉ钪?許多實用產(chǎn)品的來源。 該產(chǎn)業(yè)使用氯化鈉鹽 作為主要的原材料。 所以我的想法是—— 首先，我們先來談談線性經(jīng)濟。

10:31

So in a linear economy, they're sourcing that salt from a mine, it goes through this chlor-alkali process, made into a basic chemical, which then can get converted into another new product, or a more functional product. But during that conversion process, oftentimes salt is regenerated as the by-product, and it ends up in the industrial wastewater. So, the idea is that we can introduce circularity, and we can recycle the water and salt from those industrial wastewater streams, from the factories, and we can send it to the front end of the chlor-alkali process. Circular salt.

在線性經(jīng)濟中， 人們從一個礦里找鹽， 它會經(jīng)歷這個氯堿過程， 被制成基本的化學物質(zhì)， 接著又被轉換成其他新的產(chǎn)品， 或者更有功能性的產(chǎn)品， 但在轉換過程中， 通常都會重新 生成鹽，算是副產(chǎn)品， 這些鹽也會進入工業(yè)廢水。 所以，我們可以導入循環(huán)， 從工廠回收工業(yè)廢水中 的水和鹽， 再把它送到氯堿處理的前端。 這就是循環(huán)鹽。

11:12

So how impactful is this? Well, let's just take one example. Fifty percent of the world's production of propylene oxide is made through the chlor-alkali process. And that's a total of about five million tons of propylene oxide on an annual basis, made globally. So that's five million tons of salt mined from the earth converted through the chlor-alkali process into propylene oxide, and then during that process, five million tons of salt that ends up in wastewater streams. So five million tons is enough salt to fill three Empire State Buildings. And that's on an annual basis. So you can see how circular salt can provide a barrier to our rivers from this excessive salty discharge.

那么這會有多大的影響呢？ 讓我舉個例子。 全世界的環(huán)氧丙烷有 50% 是通過氯堿過程制作出來的， 也就是全球每年總共生產(chǎn) 約五百萬噸的環(huán)氧丙烷。 那么，從地球開采的五百萬噸鹽， 通過氯堿過程轉換成環(huán)氧丙烷， 在這個過程中， 五百萬噸的鹽最后會進入廢水中。 五百萬噸的鹽 足以填滿三個帝國大廈， 那還只是一年的量。 這樣大家就可以了解到 為什么循環(huán)鹽 可以幫助我們的河流 抵御過多的鹽排放。

12:05

So you might wonder, "Well, gosh, these membranes have been around for a number of years, so why aren't people implementing wastewater reuse? Well, the bottom line is, it costs money to implement wastewater reuse. And second, water in these regions is undervalued. Until it's too late. You know, if we don't plan for freshwater sustainability, there are some severe consequences. You can just ask one of the world's largest chemical manufacturers who last year took a 280-million dollar hit due to low river levels of the Rhine River in Germany. You can ask the residents of Cape Town, South Africa, who experienced a year-over-year drought drying up their water reserves, and then being asked not to flush their toilets.

各位可能會納悶， “哦，天吶，很多年 以前就有這些薄膜了， 為什么大家都不去做 廢水循環(huán)利用呢？ 根本原因就是， 做廢水再利用需要資金。 其次， 在這些區(qū)域水的價值被低估了， 沒有及時進行循環(huán)再利用。 如果我們不規(guī)劃淡水的可持續(xù)性， 就將要面臨嚴重的后果。 可以問問世界上最大的化學品制造商， 去年，他們因為德國萊茵河水位過低， 遭受了 2 億 8 千萬美金的損失， 也可以問問南非開普敦的人民， 他們遇到了一年比一年嚴重的干旱， 讓所有儲存的水被耗盡， 甚至被限制沖馬桶，以節(jié)省水源。

12:59

So you can see, we have solutions here, with membranes, where we can provide pure water, we can provide pure salt, using these membranes, both of these, to help to protect our rivers for future generations.

所以我們可以看到， 現(xiàn)在我們有解決辦法，那就是薄膜， 用這個方法可以得到純凈水， 得到純鹽， 一石二鳥。 為未來的世代，保護我們的河流吧。

13:15

Thank you.

謝謝。

13:16

(Applause)

（掌聲）