TDS is often mentioned when measuring and testing water sources, so what is TDS? How does this indicator relate to water resources and how can it be reduced in the country?
What is TDS?
TDS: Total Dissolved Solids – Total dissolved solids, which is the total number of charged ions, including minerals, salts or metals present in a given volume of water, usually expressed as a function of mi / L or ppm (parts per thousand). TDS is often used as the baseline to determine the cleanliness of water sources.
Where does TDS come from?
The dissolved solids in question exist as both negative and positive ions. Since water is always very soluble, it tends to get ions from the objects it comes in contact with. For example, when flowing underground in rocky mountains, water will take calcium ions, minerals. When flowing in pipes, water will take metal ions on the pipe surface, such as iron, copper, lead (plastic pipes).
Relationship between TDS and purity
According to current regulations of WHO, US EPA, and Vietnam, TDS must not exceed 500mg / l for drinking water and not exceed 1000mg / l for domestic water. Smaller TDS indicates cleaner water (if too small, there are almost no minerals). Some applications in the electronics manufacturing industry require a TDS of no more than 5.
However, the opposite is not always true. Water with high TDS is not necessarily unsafe, possibly because it contains many beneficial ions. Mineral waters are generally not limited to TDS.