In simple terms, zero liquid discharge means treating wastewater for recycling and repeated circulation. Is such treatment necessary? What are the purposes of zero liquid discharge for wastewater? This article provides a brief overview of wastewater zero liquid discharge, together with manufacturers of Online Water Quality Monitoring Instruments.

In industrial production, wastewater generated from manufacturing processes is reused. Highly concentrated wastewater containing pollutants is further treated with dedicated processes for recycling. Insoluble substances are filtered out by specialized equipment to enable water recycling, so that little wastewater or liquid waste is discharged outside the plant. What are the core purposes of adopting such treatment? They fall into three key aspects:

1. Highly concentrated organic industrial wastewater contains large quantities of toxic and harmful substances. These substances may accumulate in natural environments such as water bodies and soil, and enter the human body through food chains, posing health risks and potentially triggering illnesses.
2. Through biological degradation, some highly concentrated organic wastewater may lead to oxygen deficiency or anaerobic conditions in receiving water bodies. This may cause aquatic organisms to die, produce foul odors, degrade water quality and harm the surrounding environment.
3. High concentration organic wastewater may cause sensory pollution with low water transparency. It disturbs the normal growth of aquatic organisms and microorganisms, weakens the self‑purification capacity of water bodies, degrades overall water quality and interferes with people’s daily lives.

Is zero liquid discharge mandatory for all cases? Enterprises may pursue zero liquid discharge where feasible. For enterprises that discharge wastewater, wastewater shall be treated by relevant processes. Each indicator of treated wastewater shall be analyzed with water quality detectors, and discharge can be performed only after all indicators meet relevant standards.