Zero wastewater discharge system

Process flow:

1. Wastewater Collection and Preliminary Treatment: After collection from the production line, wastewater undergoes simple pretreatment, such as screening to remove large particles and sedimentation or filtration, to remove most pollutants and prepare for subsequent treatment.

2. Heavy Metal Removal and Sorting: For wastewater containing heavy metals, precise heavy metal removal technologies are employed, using methods such as adjusting pH and redox potential to remove heavy metals. For example, for heavy metal-containing wastewater (such as electroplating wastewater), rapid physicochemical or specialized adsorption technologies are used to precisely remove heavy metal ions.

3. Biological Treatment and Water Purification: The next stage is biological treatment. Using biochemical technologies such as MBR (Membrane Bioreactor), microorganisms decompose organic matter and recalcitrant pollutants in the wastewater. For wastewater containing complex, recalcitrant organic matter, enhanced biological treatment technologies (such as specialized membrane bioreactors) are applied to significantly improve the degradation efficiency of organic pollutants and the system's tolerance.

4. Advanced Treatment and Reuse: Pretreated wastewater undergoes further purification using advanced oxidation or precision membrane separation technologies (such as reverse osmosis and nanofiltration), significantly improving the quality of the produced water to meet the high standards for reuse in production processes.

5. End-of-Line Concentration and Crystallization: High-salinity concentrate generated during system operation is treated using rapid thermal concentration technologies (such as mechanical vapor recompression evaporation, MVR) to recover water and ultimately concentrate and crystallize the total dissolved solids into solid salts. These crystallized salts are then disposed of in compliance with regulations by qualified professional units, completely eliminating the possibility of liquid wastewater discharge.

6. Water Reuse: The treated water can be reused in various stages of the production process, maximizing water resource utilization and achieving zero wastewater discharge.

Technological Advantages

Precise Diversion and Pretreatment: Accurately classifies and collects different types of wastewater at the source, providing a foundation for subsequent rapid and targeted deep treatment.

Rapid Treatment Technology: Combines various advanced technologies, such as reverse osmosis, nanofiltration, and MVR evaporation, to achieve a high proportion of water reuse and resource recovery.

Resource Utilization: Through technologies such as crystallization, salts and other substances in wastewater are recovered and reused, reducing solid waste generation.

Application Cases

Zero-Discharge Wastewater Project at a Power Plant in Inner Mongolia: Through processes such as chemical softening, DTRO membrane concentration, and MVR evaporation crystallization, annual wastewater discharge is reduced by 150,000 tons, and 2,000 tons of salts are recovered.

Centralized Treatment Project in a Dyeing and Printing Industrial Park in Zhejiang: Employing technologies such as biochemical treatment, ultrafiltration and reverse osmosis dual-membrane methods, and electrodialysis, 100% wastewater reuse is achieved, saving over 20 million yuan annually.

The zero-discharge wastewater system not only meets stringent environmental protection requirements but also achieves a win-win situation for both economic and environmental benefits through resource recovery and water reuse.