Water is considered a universal solvent because it can dissolve and absorb molecules of various substances. The number of dissolved particles in a certain volume of water is called the total dissolved solids (TDS) level. Understanding the TDS level in water and the total dissolved solids present in it can reflect the overall condition of water quality. In this article, you can learn about the different types of total dissolved solids, how to measure them, and how to reduce the TDS level in water.
1. What is TDS TDS, which is the abbreviation of Total dissolved solids, means total dissolved solids, also known as the total dissolved solids. This indicator is measured in milligrams per liter (mg/L), which reflects the content of solid matter dissolved in each liter of water. For the relationship between TDS values and water quality, we can understand it as follows: When the TDS value is between 0-99PPM, the water quality is generally considered pure water; When the TDS value is between 100-200PPM, the water quality is considered purified water; When the TDS value is between 200-400PPM, the water quality belongs to the category of tap water.
Generally speaking, the TDS value is the concentration of impurities in water. Impurities in water generally contain the following substances: Minerals: such as calcium, magnesium, potassium, etc. (natural sources, some of which are beneficial to the human body). Inorganic salts: such as chlorides, sulfates, bicarbonates, etc. Heavy metals: such as lead, arsenic, copper, etc. (harmful pollutants). Chemicals: such as pesticides, chlorine, herbicides, etc. (artificial pollution).
However, the TDS value does not directly reflect the quality of water. A high TDS value (such as more than 600) may indeed mean poor water quality, but a lower TDS value does not always mean better water quality. Therefore, the TDS value and the quality of water are two different concepts. The quality of water requires a comprehensive consideration of multiple indicators, including microbial indicators, toxicological indicators, sensory characteristics indicators, etc., and these indicators are not entirely measured by the TDS value.
2. TDS measurement tools and methods There are two main methods for measuring TDS: one is to use a TDS test pen. The principle of TDS meter is to estimate TDS by measuring the conductivity of water, which is applicable to pure water, tap water, etc. Its operation is simple. Just immerse the probe in water and read the value (unit: ppm or μS/cm). However, it has certain limitations. It can only reflect the total dissolved amount, cannot distinguish between beneficial minerals and harmful pollutants, and is not sensitive to non-conductive organic matter (such as pesticides). Second, conduct professional water quality testing. Professional water quality testing is suitable for suspected water source pollution (such as well water, industrial surrounding water sources) and water quality baseline analysis before installing water purification equipment.
3. Methods for reducing TDS in water Common methods for reducing TDS in water are as follows. Physically, reverse osmosis (RO), distillation, ion exchange resin and other methods can be used; chemically, flocculation precipitation, activated carbon adsorption and other methods can be used; in source control, avoid pollution and choose water sources.
In summary, TDS meter cannot indicate what types of TDS exist, which is the most important information for understanding water quality. It is recommended to use a home water test kit or a laboratory water analyzer to accurately reveal the type of TDS in the water.
