Zero Liquid Discharge (ZLD): Processes and industrial solutions
Zero Liquid Discharge (ZLD) refers to a wastewater treatment process in which no liquid wastewater needs to be discharged. The aim is to recycle water completely and recover valuable materials.
- Up to 95% water recovery possible
- Significant reduction in disposal costs
- Compliance with strict environmental regulations
- Sustainable solution for industrial processes
ZLD systems are often based on modern evaporator technology
WHAT IS ZERO LIQUID DISCHARGE (ZLD)?
Zero Liquid Discharge (ZLD) is an industrial wastewater treatment process in which all liquids are treated in such a way that no wastewater remains at the end. Instead, the water is purified and reused, whilst solids are concentrated and disposed of.
The aim of ZLD systems is to create closed-loop water cycles and make businesses independent of external disposal infrastructure.
WHY IS ZLD USED?
Zero Liquid Discharge (ZLD) is a strategic component for companies that…
- wish to use water resources sustainably and reduce their fresh water requirements,
- must meet stringent legal requirements regarding wastewater discharge,
- operate in water-scarce regions,
- and wish to recover valuable materials from wastewater streams.
Particularly in times of increasing environmental regulations and growing water scarcity, ZLD is coming increasingly into focus as a sustainable solution for industrial water use and management.
ZLD OFFERS A CLEAR SOLUTION:
Water is recycled rather than disposed of!
BENEFITS OF ZERO LIQUID DISCHARGE
MKR-Metzger supports industrial companies in implementing ZLD concepts using tried-and-tested technologies for process media and wastewater treatment. The focus is on modular, cost-effective and reliable solutions.
Reduction in disposal costs of up to 90%
Minimising environmental impact – no liquid waste is discharged into watercourses
Independence from external waste management companies
Compliance with strict legal requirements – improving environmental compliance
Recovery of water and raw materials
Zero Waste
From planning to the finished solution – all under one roof!
PRACTICAL EXAMPLE:
ZLD IN ELECTROPLATING
A PROJECT IN SURFACE ENGINEERING ILLUSTRATES HOW ZLD WORKS IN PRACTICE:
An electroplating plant in Germany faced the challenge of treating increasing volumes of wastewater cost-effectively whilst reducing disposal costs. By installing an ET-series evaporator in combination with the ET MaXx ZLD system, the existing plant was successfully upgraded.
THE RESULT:
- significant reduction in the volume of concentrate
- Recirculation of the distillate back into the production process
- Virtually unchanged energy and labour costs
- Return on investment in less than a year
The project clearly demonstrates that:
ZLD is not just a concept, but a viable business practice.
Read the full case study:
Wastewater treatment in electroplating using ZLD
HOW DOES A ZLD SYSTEM WORK?
A typical ZLD concept consists of several coordinated stages:
1. PRE-TREATMENT:
Coarse contaminants are removed and the water flow is prepared for further treatment.
2. EVAPORATION:
The wastewater is thermally treated; water is evaporated and recovered as distillate.
3. POST-CONCENTRATION:
The remaining concentrate is further evaporated to reduce the water content as much as possible.
4. RESULT:
Distillate → Recirculation into the process
Concentrate/solids → Minimal disposal
This combination creates a closed water cycle.
We would be happy to advise you on your waterless production
TECHNOLOGIES FOR ZLD SYSTEMS
A Zero Liquid Discharge (ZLD) system is not based on a single technology, but on a combination of several processes for industrial wastewater treatment and water reuse.
The aim is to recover all the water and leave behind only minimal residues.
THE CORE TECHNOLOGY IN ZLD SYSTEMS IS THE EVAPORATION OF INDUSTRIAL WASTEWATER
This involves:
Water being evaporated, recovered as distillate and reintegrated into the process
- high separation efficiency
- ideal for complex industrial wastewater
FOR TRUE ZLD APPLICATIONS, THE REMAINING CONCENTRATE IS FURTHER TREATED:
- additional evaporation and maximum volume reduction
- minimal residual material, with solid formation where applicable
- complete water recovery
WHEN IS ZERO LIQUID DISCHARGE (ZLD) WORTH IT?
ZLD is particularly beneficial when:
- disposal costs are high
- large volumes of wastewater are generated
- water can be reused in the process
- regulatory requirements are increasing
ZLD systems are a key technology for industrial wastewater treatment and water reuse
COST-EFFECTIVENESS:
ZLD systems from MKR pay for themselves within 1–3 years, particularly where disposal costs are high.
TYPICAL APPLICATIONS FOR ZLD
MKR’s ZLD systems are energy-efficient and low-maintenance.
They are used in metalworking, surface treatment, the automotive industry, the chemical industry, electroplating and many other sectors.
In all these areas, ZLD enables a significant reduction in costs and environmental impact.
CONCLUSION
Zero Liquid Discharge (ZLD) is a forward-looking, resource-efficient concept for wastewater treatment and prevention. With MKR-Metzger’s modular treatment solutions, ZLD concepts can be implemented in a practical and cost-effective manner – from the initial stages of recycling to virtually wastewater-free production.
If you would like to find out more about suitable technologies or solutions for implementing ZLD in your business, we would be happy to advise you!