High-salinity industrial wastewater comes from multiple industrial production processes that generate wastewater containing high concentrations of salts. The salts in these wastewaters primarily come from the dissolution of raw materials, the chemical reactions that produce salts, and the salt additives used to adjust process conditions. Specifically, the sources of high-salinity industrial wastewater include, but are not limited to, the following: 

1. Many raw materials and products in industrial production are salts or can be converted into salts.

2. Additionally, certain chemical processes require the addition of large amounts of salts to adjust reaction conditions, such as pH and ionic strength. These salts will also end up in the wastewater after the reaction.

3. Secondly, high-salinity brine is generated during processes like seawater desalination and seawater utilization. In seawater desalination and direct seawater utilization, a large amount of concentrated brine is produced.

4. Furthermore, specific industries such as pharmaceuticals, dyeing, and electroplating also generate high-salinity wastewater. In pharmaceutical manufacturing, some raw materials and products are salts or can be converted into salts, and salts may also be added as reactants or regulators during production. The dyeing and electroplating industries may generate wastewater containing high concentrations of salts due to processes such as equipment cleaning and product handling.

Industrial calcium salt wastewater can have a total salt content of 1%-3.5%, with main components including inorganic salts such as sodium chloride (NaCl), sodium sulfate (Na₂SO₄), potassium chloride (KCl), and calcium chloride (CaCl). The Na⁺, Cl^-, and SO₄^2- ions account for more than 90% of the total inorganic salt ions, and there may also be organic substances like glycerol and low-carbon chain compounds. In addition, the wastewater may contain heavy metals such as lead (Pb), cadmium (Cd), and chromium (Cr), as well as oils, suspended solids, and other harmful substances like radioactive materials, which pose potential environmental and ecological risks. Furthermore, the composition of industrial high-salinity wastewater is complex, with significant variations in the concentration of components from different sources, which adds difficulty to treatment. Additionally, high-salinity wastewater is often highly corrosive and heavily polluted, requiring high standards for treatment equipment and materials.