What are the core steps of industrial wastewater zero discharge?

　　With the acceleration of industrialization, industrial wastewater discharge poses a serious threat to the ecological environment. Zero discharge of industrial wastewater has not only become a key link in environmental protection, but also an important force in promoting the green transformation of the economy.

　　According to the national standard GB/T21534-2008 "Industrial Water Usage And Conservation --- Terminology", [zero discharge] is defined as "the production water system of an enterprise or main unit achieves zero industrial wastewater discharge."

　　So what are the core steps of industrial wastewater zero discharge?

　　The core steps of industrial wastewater zero discharge mainly include:

　　1. Wastewater pretreatment

　　The wastewater is initially treated to remove large particles or easily treatable pollutants through screens, sedimentation tanks and other equipment.

　　2. Concentration and evaporation

　　The wastewater is concentrated through reverse osmosis and other technologies, and most of the dissolved substances in the water are separated, separating the clean water and high-concentration brine that can be reused. The residual water is then evaporated with evaporation device to precipitate solid salt.

　　3. Crystallization recovery

　　The concentrated brine after evaporation is further crystallized, and the dissolved salts or other solid substances in the concentrated solution are separated by crystallization to form reusable solid waste. For some wastewater containing valuable heavy metals or rare elements, they can also be extracted and recovered through ion exchange, adsorption and other methods.

　　4. Recycled water treatment

　　The evaporated water can be further treated and then reused in the production process.

　　With own core patented technology of "zero discharge" for metal industrial wastewater, through the technical route of "wastewater diversion, classification treatment, wastewater reuse, and resource recovery", by adopting the combined process of "heavy metal high-precision removal pretreatment + OSMMBR biochemical technology + SPNR technology + MVR crystallization technology" of Shangchen Environment, all the treated heavy metal wastewater are used for production, the wastewater reuse rate is increased to 99.6%, which maximized the recycling of water resources.