Water, being the universal solvent, dissolves many impurities in it. These impurities include organic substances such as minerals from the natural sources and inorganic materials generated by industries, road salts, pesticides, and other pollutants present in our environment.
Some of these impurities are large and can remove by the usual filtration method. But some contaminants are harmful to us and cannot be removed by the general filtration method. Therefore, it is essential to learn about these impurities and how to remove them.
What is TDS Level in Water?
TDS or total dissolved solids are the contaminants left in the water even after the standard filtration method.
In other words, the amount of dissolved particles in a particular volume of water is called a TDS level. The standard unit set for measuring the TDS level is mg/l. The Environmental Protection Agency in the US has set the maximum recommended level of 500 milligrams per liter (mg/L).
Why is it Necessary to Measure the TDS level in the Water?
In ancient times, the high TDS level of water was due to the presence of any mineral in a high amount. Nowadays, the High TDS level of water is due to various chemicals used in factories or industrial waste, making it toxic.
However, TDS is the measure of microscopic solids present in our pool. It does not differentiate between the impurities present due to poisonous chemicals and the essential minerals required for our functioning.
Following are the effects of using a high TDS level of water in our daily life:
- Hardness- High TDS means more ions and minerals dissolved in it. In case these ions are carbonates of calcium and magnesium, then it results in the hardness of the water. This hard water will not only affect our body but also reduces the froth formation of soap.
- Scale formation- Calcium and magnesium carbonates settle down in pipes and faucets, causing blockage due to scale formation.
- Taste- Various impurities can change the taste of the water we drink. Excess amounts of chlorides of sodium and potassium can make the water taste salty.
- The corrosive ability of water- some regions having high mineral content such as fluorides, chlorides, sulfates, etc. will increase the TDS of that level. Iron can corrode pipelines and even affect our dishes.
What Should be the TDS Level of Water?
Our body requires certain minerals in a specific amount(neither too low nor too high) for our body’s proper functioning. According to Dr. John Sorenson, “Minerals in drinking water are more easily absorbed than the minerals from food.”
The packed drinking water available in bottles have shallow TDS water. The purifying devices remove everything from the water, including the beneficiary minerals required by our body, making the TDS as low as 10mg/l.
If water with such a low TDS consumed for a long time, it will act as a hypotonic solution. Instead of supplying minerals required for the proper functioning of our body, it will leach out such minerals. So a shallow TDS water is inferior for good health compared to the optimum level of TDS.
High TDS water means more contaminants or minerals present in the water. Not only are toxic materials harmful to our body but also the water with high mineral content.
TDS Level Chart and its Effects
Given below is the chart regarding the various effect of the TDS level of water we are consuming.
|TDS LEVEL (MG/L)||REASONS FOR ACCEPTABILITY / NON-ACCEPTANCE|
|Less than 50||Not acceptable. Because water with such a low TDS level is devoid of the essential minerals.|
|50-150||Acceptable. However, the TDS level in the range of 80-150 is considered ideal. If you are using an RO water purifier then make sure the TDS level of purified water is not below 80 mg/L.|
|150-250||Acceptable. This is the ideal TDS range as far as cardiovascular fitness is considered.|
|250-350||Acceptable. Most urban Indian homes have access to water in this TDS range.|
|350-500||Acceptable. As per the BIS guidelines, TDS level below 500 mg/L is acceptable.|
|500-900||Not acceptable. Use a RO water purifier with TDS controller or mineraliser.|
|900-1200||Not acceptable. Use a RO water purifier with TDS controller or mineraliser.|
|1200-2000||Not acceptable and not fit for drinking. Choose a RO water purifier that can purify water with up to 2000 mg/L.|
|Above 2000||Do not drink. Most home water purifiers can’t purify water with TDS level over 2000 mg/L.|
Affect of TDS on our Health
1. Excessive mineral content- some minerals such as zinc, iron, chromium, and selenium, are essential for our body’s proper functioning. But if they are present at elevated levels can cause toxic effects in our collection.
2. Large intakes of fluoride (especially in childhood) may stain and even weaken the teeth.
3. High levels of TDS means it is unfit for consumption and several diseases like nausea, lung irritation, rashes, vomiting, dizziness, etc.,
4. Drinking water with an elevated amount of TDS for more extended periods will expose the body to various chemicals, toxins and may cause kidney stones and other health effects.
5. Low mineral content will result in improper functioning of our organization. Little TDS water not only makes our body devoid of mineral but also acts as a hypotonic solution and tries to dissolve the minerals of our body into itself.
Hence minimum 150ppm but not more than 500 ppm can be termed as good for health.
Ways to Reduce TDS in Water
As we have read earlier, the TDS level may be high due to the presence of free ions. In the deionization process, we can remove these free ions by applying an electric potential difference over two electrodes, which often made of porous carbon. As a result, negative ions move towards the positive electrode(anode) and stored there, whereas the positive ions stored in a negative electrode(cathode).
The water left is now free of ions and hence called deionized water. However, the water must be passed through the reverse osmosis unit to remove non-ionic pollutants.
2) Reverse osmosis
This may consider as the most convenient method to be used at homes. In the RO units, water force to pass through the reverse osmosis membrane by applying pressure that is greater than the naturally occurring osmotic pressure to deionize the water in the process, allowing pure water through while holding back a majority of contaminants.
The major disadvantage is that the water collected becomes devoid of all the minerals.
In this process, water vaporizes using a heat source. As a result, pure water molecules get separated from the contaminants having a higher boiling point than water. The water boiled until it begins to evaporate.
The evaporated water is then liquefied and collected into a container. However, it has two disadvantages: firstly, distillation units are too costly and cannot install at homes, and secondly, it does not remove chlorine or its by-products.
Water has always blamed for the good and bad effects on our bodies. All the metabolism of our body takes place with the help of water. But the population growth has put pressure on existing groundwater, especially in developing countries. Thus it is vital to check the purity of the water we are drinking by checking its TDS level.
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