Total dissolved solids, abbreviated as TDS, is a measure of the combined concentration of all dissolved substances in water. Within the reverse osmosis industry TDS is known as as the total cations and anions in the water. TDS is the sum of either anions or cations in the water. TDS is usually expressed in parts per million (ppm) or milligrams per liter (mg/L) of water. These substances can include inorganic salts, minerals, metals, cations (positively charged ions), anions (negatively charged ions), and some organic matter.
The measurement of TDS provides an indication of the overall quality of water and is commonly used in water quality assessments for various purposes, including:
- Drinking Water Quality - High TDS levels in drinking water can affect the taste and odor, and extremely high concentrations may be an indication of contamination or the presence of undesirable substances.
- Agricultural and Irrigation Water - TDS levels in water used for irrigation can impact soil quality and plant health. Excessive TDS may contribute to soil salinity, affecting crop growth.
- Industrial Processes - Many industrial processes require water with specific TDS levels. High TDS can lead to scaling and corrosion in pipes and equipment, affecting the efficiency of industrial operations.
- Aquaculture - TDS levels in water bodies can influence the health of aquatic organisms, including fish and other aquatic species.
- Environmental Monitoring - Monitoring TDS in natural water bodies helps assess water quality and the impact of human activities on aquatic ecosystems.
TDS can be measured using various methods, including conductivity meters, which estimate TDS based on the electrical conductivity of water. While TDS is a useful indicator of water quality, it doesn't provide information about the specific types of dissolved substances. For a more detailed analysis, additional tests may be required to identify and quantify individual ions and compounds present in the water.