Search

What Total Dissolved Solids Test Tells About Your Water Quality?



Even in big cities like Beijing and Shanghai, water from the tap may carry hazardous impurities like sediments, rusts, bacteria, viruses, chlorine, or heavy metals. Even though Chinese standards on water are equivalent to international standards, it is still not possible to ensure the safety of water due to the widespread heavy use of chemicals by industry and agriculture.

即使在北京和上海这样的大城市,自来水也可能携带有害污染物,如沉积物、锈菌、细菌、病毒、氯或其他重金属。尽管中国的水标准与国际标准相当,由于工农业普遍大量使用化学品,水质安全仍然无法得到保证。



Even though water coming out from the water plant can meet the required standards, slight pollution usually occurs during the pipe delivery, due to the bad condition of some pipes in certain areas. That is why it is always good to know what is flowing from your own tap. At Greenwave we commonly used TDS testing, which is a very simple technique to quickly asses the quality of water that our clients are using.

尽管自来水从水厂出水时是达标的,但是由于某些地区的管道状况不好,水在管道输送过程中通常会被轻微污染。这就是为什么了解您家自来水的水质情况是必要的。Greenwave通常使用TDS笔测试水质,这是一种非常简单的方式,可以快速评估用户使用的水质。


TDS meter is portable and readily available testing kit commonly used by Greenwave and many other industry people to check the purity AND SAFETY of the drinking water. It can provide vital information to our consultants. In the content below we will explain what information can be provided by the TDS test and how to reduce the TDS reading. You will also learn about the limitations of the test.

TDS笔是一种便携式测试工具,Greenwave通常使用它来检查饮用水的纯净度和安全性。它可以为我们的顾问提供重要的信息。在下面的文章中,我们将解释TDS测试可以提供哪些信息以及如何减少水中的杂质。您还将了解这个受欢迎的测试工具有哪些局限性。



Picture shows the TDS pen that Greenwave uses for testing. Here comparison of TDS reading between tap and purified water at the same household.

上图为Greenwave测试时使用的TDS笔。这里比较了同一家庭自来水和纯净水的TDS读数。

---

What is TDS?

TDS指什么


This indicator measures Total Dissolved Solids and represents total concentration of dissolved substances in water that are smaller than 2 microns. TDS can be both organic and inorganic materials that are dissolved in water such as calcium, magnesium, sodium and potassium ions and carbonate, chloride, sulfate and nitrate anions.

该指示器能测量总溶解固体,并能显示水中溶解物质的总浓度。TDS显示的是溶解在水中的有机和无机物质,例如:钙、镁、钠和钾离子以及碳酸盐、氯化物、硫酸盐和硝酸盐阴离子。



TDS can come from different sources such as minerals in chemicals used in water treatment, chemical fertilizers from the farms etc.

TDS有不同的来源,如工厂做净化水处理时使用的化学品中含有矿物质掺杂在自来水中,农场使用的化肥流入自来水等。


A high level of TDS in water can lead to a number of health problems. The presence of potassium, sodium, chlorides increases the TDS level in the water without really posing a threat to human safety. However, the presence of toxic ions such as lead, nitrate, cadmium, and arsenic present in water can lead to a number of serious health problem. This is especially important for children because they are much more sensitive to contaminants because their defense systems are not fully developed yet.

水中TDS含量高会导致许多健康问题。钾、钠、氯化物的存在会增加水中的TDS水平,但不会真正对人类健康安全造成威胁。然而,水中铅、硝酸盐、镉和砷等有毒离子的存在会导致许多严重的健康问题。这对儿童的影响尤其重大,因为他们身体的防御系统还没有完全发育,他们对污染物就更敏感。



Chlorine could be tested as well simply

余氯也很容易检测

---

Facts about TDS test

TDS检测现实性


TDS test can not tell us what exactly is in the water- if the high reading is caused by toxic pollutants or simply by the Calcium and Magnesium ions that cause hardness of water. TDS simply tells us what is in water besides the pure H2O. Chlorine can not be detected by the TDS test because it is not a dissolved solid.

TDS测试不能告诉我们到底水中有哪些物质-读数高可能是因为水中有(有毒污染物)或(钙和镁离子-它们会造成硬水)。TDS只是告诉我们除了纯水之外,水中还有其他物质。TDS测试不能检测到氯,因为它不是溶解固体。


---

TDS test is still helpful


So, TDS shows both good and bad particles, is it helpful? Cities like Beijing and Shanghai source their tap water from mixed sources and use both surface and ground water. Some of the dissolved solids that are detected by TDS test can be actually good minerals. When the water goes through the mineral rocks, it collects some of the minerals present in the geological layers. That’s how we get mineral water! However, since we live in a highly industrialized country with multiple pollution issues, are a lot of chemicals and toxic particles can be found in air, soil and water. In 2012, the Ministry of Land and Resources released report which stated that 45% of ground water from 4,727 testing sites in 200 cities across China was graded as excellent, good or fair, while 55% was poor or very poor[4]. And despite efforts to clean up the water resources, it takes many years to totally reverse the bad effects.

就是说,TDS不仅显示水中好的物质也能显示不好的物质,那么它可靠吗?像北京和上海这样的城市从混合水源中获取自来水,同时使用地表水和地下水。TDS测试检测到的一些溶解固体实际上是有益矿物质。当水通过矿物岩石时,它收集了地质层中的一些矿物质。我们就是这样得到矿泉水的!然而,由于我们生活在一个高度工业化的国家,存在着多种污染问题,因此在空气、土壤和水中都会发现大量的化学物质和有毒颗粒物。2012年,国土资源部发布报告称,全国200个城市4727个地下水检测点,45%的地下水被评为优、良、中,55%的地下水被评为差、极差[4]。尽管人们努力清理水资源,但要完全扭转这种不良影响需要很多年。

Therefore, it is highly likely that some of the harmful particles can be in the water around us which might not have been caught at the earlier stages of municipal purification system. Current standards for municipal water require mandatory checking of 106 testing subjects (which is compliant with international standards). But how many toxic substances are there in the whole China? (But we will tell you more about municipal water filtration in another article, stay tuned!) The most essential method to solve the tap water crisis is cleaning water resources. However, at the current stage, the most practical choice for providing clean water is using the best water filtration technology possible.

因此,我们使用的水中很可能存在一些有害颗粒物,而这些颗粒物在市政净化系统的早期阶段可能不会被捕获。现行的城市用水标准要求对106项指标进行强制性检查(与国际标准接轨)。但是全中国到底有多少种有毒物质呢?(我们将在另一篇文章中告诉您更多有关市政水过滤的信息,敬请关注!)解决自来水危机最根本的方法是净化水资源。然而,在现阶段,提供净化水的最实际的选择是使用最好的过滤技术。

---

Low TDS means pureness


But we have the simple rule which says: “the higher the reading, the further your water is from the pure H2O.”Greenwave has been monitoring the TDS readings in Shanghai tap water for over 10 years and the tap water within the city had been improving gradually. You can see our measurements over the years on the below chart. The TDS reading of tap water in Shanghai dropped significantly these years with the upgrade of treatment facilities and change of water source from Huangpu river to Qingcaosha reservoir along Yangtze River.

有一个简单的规则,那就是:“TDS读数越高,你的水离纯净越远。”Greenwave对上海市自来水TDS进行了10多年的监测,上海市自来水水质正在逐步好转。您可以在下表中看到我们多年来的测量结果。近年来,随着上海市自来水处理设施的升级改造和水源地由黄浦江改为长江青草沙水库,上海市自来水TDS读数明显下降。



As for Beijing, the water resources consist primarily of ground water(mineralized) surface water (for example Miyun reservoir), and Yangtze riverwater (delivered to Beijing via South-to-North Water Diversion Project).

就北京而言,水资源主要包括地下水(矿化)地表水(例如密云水库)和长江水(通过南水北调工程输送到北京)。



Based on Beijing Water Resources Bulletin 2019 [3] 依据《北京市水资源公报2019》

TDS numbers could vary due to different district or the age of the apartment buildings, and condition of the piping system. As for now, the average of TDS number in Beijing is oscillating between 140 and 300 for a newly built apartment compound, but we also had clients with readings as high as 600! When we see a high TDS reading in the city, we know that part of it is probably the hard water (Mg and Ca ions are detected by the TDS) but there are certainly other things in the water, and we cannot say without more detailed lab testing.

TDS数值可能会因不同地区或公寓楼的年限以及管道系统的状况而有所不同。到目前为止,北京新建的公寓楼TDS的平均值在140-300之间,但我们也有客户家里自来水的读数高达600!当我们看到城市里自来水的TDS读数很高时,我们知道一部分原因可能是硬水(TDS检测到镁和钙离子),但水中肯定还有其他物质,这需要通过做更详细的实验室测试才能得到结果。


---

Performance of the water filters

净水器的净化效果


When buying/using a water filter, we recommend looking at the micron measurement that the filter is designed to catch if it’s available. A micron =one millonth of a meter (1000 microns=1mm).

当购买空气净化器或净水器时,我们建议查看过滤器设计用于捕捉的粒子微米数值(如果可以查到)。1微米=百万分之一米。(1000微米=1mm)


Theoretically water filters with component of RO membrene will remove the most dissolved solids. These using activated carbon, ultrafiltration membrene or other components could not remove all. That is part of reason they are often claimed/advertised to keep the minerals. Please check the following picture for details.

理论上来说,使用RO膜的直饮水机能去除最多的溶解性杂质,因而让人也更容易让谁干净。仅仅使用活性炭、超滤膜等组件的净水器很难去除相关杂质。这些产品也因此经常被宣传为保留矿物质。下图是很好的解释


Source: Water Proccessing: Third Edition’, Wes McGowan, Water Quality Association, 2001


---

Why some filters do not lower TDS?

部分净水器不能降低TDS



Basic filters (non reverse osmosis and distillation based products) such as whole house filtration system, water softeners, shower filters, faucet filters and so on could not lower TDS reading of the filtered water dramatically. These systems mainly target at the impurities like rust, sands, chlorine and many other chemicals in the water, which means the smaller ones like metals and other charged particles can easily escape. That is to say, no matter how many stages of filters are used inside, the filtered water will be with almost no change for the reading of TDS. These basic filters can even increase the TDS reading after being used for some time, which does not necessarily mean that they are not working though.

简单过滤器不能有效降低TDS(非基于逆渗透、蒸馏技术的设备), 如常见的中央净水器、中央软水器、超滤净水器、活性炭净水器、沐浴净水器、水龙头净水器等。这些过滤器主要是去除水中的大颗粒杂质如泥沙、铁锈以及余氯和其它化学物质,对直径更小的杂质如金属离子很难去除--这些离子恰恰是TDS的主要构成。也就是说,无论简单过滤器有多少级过滤、用料多少,都无助于降低TDS值。在实际使用过程中,过滤水的TDS数值可能会比原水更高。当然,这并不意味着这些过滤设备没有效果。我们只是不建议饮用。



If you are using some filter, one way to simply tell if it can lower the TDS could be checking out the materials. The following is some basic effectiveness for the materials often used in the filters.

如果你正在用净水器,一个简单可以判断它是不是降低TDS的方法是看它的用材。下面是净水器中常用材料对TDS的影响。

Activated carbon: is effective at removing chlorine, pesticides, sediments, TVOCs, and improving the taste of your water, it doesn’t remove minerals, salts, or compounds that are already dissolved. (dissolved solids and very small particles don’t get removed)

活性炭:能有效地去除氯、杀虫剂、沉淀物、挥发性有机化合物,改善水的口感,但它不能去除已经溶解的矿物质、盐或化合物。(溶解的固体和非常小的颗粒不会被去除)



KDF: (Kinetic Degradation Fluxion) process media, high-purity copper-zinc alloy that reduce contaminants and chlorine using anoxidation/reduction (redox) reaction. The zinc and copper ions are released from the KDF during chlorine removal and they are detected by the TDS test.

KDF:高纯度铜锌合金,通过氧化/还原反应去除污染物和氯。在氯被去除过程中,锌和铜离子也会从KDF中释放出来,在TDS测试中能被显示出来。



Spun fiber: among the most basic material removing big-sized particles such as rust, sands, sediments, but the smaller ones like metals and other charged particles can easily go through. Please remember that TDS shows only particles in water that are smaller than 2 microns, so some of the bigger particles blocked by the Spun fiber are even too big to be detected by the TDS testing.

PP棉:最基本的净水材料之一,能过滤水中的大颗粒如:铁锈、沙子、沉淀物和部分氯,但较小的颗粒,如金属和其他带电粒子则很容易通过聚丙烯纤维。请记住,TDS仅显示水中小于2微米的颗粒,因此一些能被聚丙烯纤维阻挡的较大颗粒无法通过TDS测试检测到。



Resin: exchanging the mineral ions out which are causing hardness in water for sodium. TDS will be hardly changed within the process.

软化树脂:树脂能吸附帮助置换水中的钙镁离子,但是有新的离子会进入水中。因而很难改变TDS



Tourmaline: mineral stone that can add minerals, activate and alkalize the water. Such water has better taste and applied to the skin gives an excellent effect of moisturizing and absorption. We use it for our Alatai drinking water purifier. However, re-mineralizing means adding GOOD particles to the water thus increasing the TDS reading to some extent.

托玛琳:可以增加矿物质、活化水质、调节水的PH值。流过托玛琳材料的水口感肯能更好,如果用来洗浴的话能够滋养皮肤。我们在Alatai直饮水机等产品中使用这样材料,用来补充矿物质,因此也一定程度的增加TDS读数。

Ultrafiltration membrene- removing particles smaller to 0.01 um. However, for the super metal ions, they will still escape through. Thus, it will not change the TDS reading.

超滤膜-能去除小到0.01微米直径的溶解物,但对于直径更小的金属离子等很难有作用。因此不改变TDS。

Reverse osmosis membrene- removing particles smaller to 0.0001 um. Only water molecules could go through theoretically. This is what we used in our Alatai, Betta and Clavo drinking water purifiers. Water through will be much lower for the TDS reading. ( less than 50 depending on the source water quality in China.) Users will notice the dramatic improvement toward taste and the purity of water.

反渗透膜-去除直径小至0.0001微米的杂质,理论上来说,只有水分子可以通过。我们在Alatai、Betta与Clavo等直饮水机用就采用这个配件。这些设备的出水TDS都远远低于自来水,根据使用地点不同,TDS一般低于50。使用反渗透膜设备的用户都会感受到口感与纯净度的大大改善。


---

Tips for doing the TDS test

TDS检测操作注意事项



· Temperature. Temperature will affect the testing results as it will affect the moving speed of the ions in the water. When doing a test, it's better to collect cold water or samples at least with same temperature.

控制水温:温度会影响测试结果,因为它会影响水中离子的移动速度。在做测试时,最好是用同样的常温温度的水样本。


· Time. Before collecting a sample, to make sure the sample is representative, it‘s better to let the tap run a while ( for example 30 seconds).

· 控制时间:在收集样本之前,为了确保样本的有效性,最好先让水龙头放水一段时间(如30秒)再采样。


· Quantity. In terms of the quantity of water sample, half of a cup will be enough.

控制水量:就水样本的容量而言,装到容器的一半就足够了。




TDS reading for the Alatai drinking water purifier

---

Extra notes about TDS

其他信息


· TDS test is good to help tell if the bottled water (except for the natural mineral water ) is clean and if the reverse osmosis drinking water purifiers work properly.

TDS测试有助于判断瓶装水(天然矿泉水除外)是否纯净,以及反渗透净水器是否正常工作。


· If your purified bottled water (not mineral, just pure H2O) and the water TDS reading is above 50, it means the water might be fake, expired or polluted. You shouldn’t be drinking this water. However, if it is natural mineral water, it is totally normal to show high TDS reading-minerals are dissolved solids.

如果您买的瓶装水(矿泉水除外,这里指纯净水)TDS读数超过50,这意味着此水可能是假的,也可能是过期或受污染的。您不应该喝这瓶水了。但是,如果是天然矿泉水,显示TDS读数高则是完全正常的,这是因为水中的矿物是可溶解固体。


· TDS test is very basic. Lab tests will be still needed if you want to know what pollutants are in your water and what is their quantity.

TDS测试能显示一些基础的信息。如果您想知道您的水里有什么污染物,污染物的数值是多少,则需要进行实验室测试。




References 参考资料

[1]https://en.wikipedia.org/wiki/Total_dissolved_solids

[2]AndyPitt Water Quality Management of Beijingin China Tsinghua science andtechnology ISSN 1007-0214 11/17 pp298-305 volume 5, number 3,September 2000i

[3] Beijing WaterResources Bulletin (2019)

http://swj.beijing.gov.cn/zwgk/szygb/202009/P020200918627119515926.pdf

[4] What’s coming out of China’s taps? https://chinadialogue.net/en/cities/4962-what-s-coming-out-of-china-s-taps/

0 views0 comments

Contact Us​

Email: service@greenwavechina.cn

Mobile (24/7): 136 2193 5343

Customer Service

WeChat Subscriber

 

Monday-Friday: 9:00 a.m. to 6:00 p.m. Beijing Time. 
Saturdays: 9:00 a.m. to 6:00 p.m. Beijing Time. 

Your Trusted Water & Air Solution Provider For Over A Decade In...

Shanghai

 

Address:

Room 1206, Fangdi Plaza, 95 West Beijing Rd., Huangpu District

上海市黄浦区北京西路95号房地大厦东楼1206室

 

Contact no: 02133315007

Beijing

 

Address:

South Gate, House A40-6, East Gaobeidian, Chaoyang District
北京市朝阳区高碑店东区A40-6号底商南门

 

Contact no: 01085860860

Guangzhou

 

Address:

Room 815, 289 Art Park Life Building, Guangzhou Avenue Central, Yuexiu District.
广州市越秀区广州大道中289号289艺术园区生活楼815室

Contact no: 02087006486

Greenwave China @ All Rights Reserved. 沪ICP备16046494号