Zero Liquid Discharge (ZLD SYSTEM)

Project Description

Waste discharge and recover water for reuse

Waterman Engineers Australia are one of the leading manufacturers of Zero Liquid Discharge (ZLD) system. A ZLD system is a treatment process which is used to remove all the liquid waste from a system. The goal of ZLD water treatment is to reduce wastewater economically and produce potable water that is fit for normal use. Zero discharge system is an advanced treatment method that comprises ultrafiltration, reverse osmosis, evaporation and fractional electro deionization. And we are a well-known supplier of ZLD systems.

Zero Liquid Discharge (ZLD SYSTEM)

Why is there a need for Zero Liquid Discharge System?

In many Industries, such as power, oil & gas, chemicals, mining and others, a large amount of wastewater is generated that has to be managed. Conventionally, this discharge of wastewater is done via a plant outfall to a surface water body like an evaporation pond, or in some cases deep well injected. These practices lead to many environmental concerns by the public in many regions of the world, as water is a scarce source and its management should be monitored. These concerns have resulted in the establishment of ZLD processes by many industries to lessen their environmental footprint and enhance sustainability. And, Waterman Engineers Australia are best zld suppliers you can find for this system.

Zero Liquid Discharge

If we talk about the world, ZLD has become necessary in India during the last decade due to heavy contamination of local waters by industrial wastewater in order to ensure the future of their rivers and lakes. In Europe and North America, the urge towards ZLD has been raised due to the high costs of wastewater disposal at inland facilities. So, as an exporter of Zero Liquid Discharge system, we keep the requirements of different regions in mind, and provide these systems accordingly.


  • Falling Film Brine Concentrators
  • Forced Circulation Crystallizer
  • Horizontal Spray Film Evaporator
  • Hybrid Systems with Membrane Pre-Concentrators
  • Biological Treatment
  • Solids Waste Handling

Zero Liquid Discharge Plant Benefits & Applications:

Recover valuable resources from the wastewater which can either be sold or reused during industrial processes. Here are some examples:

  • Production of valuable potassium sulphate (K2SO4), fertiliser from a salt mine
  • Concentration of caustic soda, sodium hydroxide (NaOH) to 50 and 99% purity
  • Minimise coal mine wastewater treatment costs by recovering pure sodium chloride which can be sold as a road salt.
  • Decrease the volume of wastewater and lowers the costs of waste management.
  • On site recycling of water, thus decreasing the need for water intake and meeting treatment requirements.
  • Minimise the truck transportation costs for off-site disposal and the related environmental hazards

ZLD Plant Designs Factors:

What are the factors necessary to be considered while designing? Here they are:

  • The respective contaminants in the discharge stream
  • The volume of the dissolved material
  • The required design flow rate

Concerned Chemicals For Zero Liquid Discharge Equipment:

Careful consideration of water chemistry is needed to design the zero liquid discharge system. The concerned chemical constituents for a zero liquid discharge system are as followed:

  • Sodium
  • Potassium
  • Calcium
  • Magnesium
  • Barium
  • Strontium
  • Silica
  • pH
  • Chloride
  • Fluoride
  • Sulfate
  • Nitrate
  • Phosphate
  • Ammonia
  • Boron
  • Alkalinity
  • Oil & Grease

Table 1: Chemical constituents of concerned while designing a zero liquid discharge system

ZLD System Design:

Regardless of many sources of wastewater stream, a ZLD system usually consisted of two steps as shown in figure

ZLD Basic Blocks
Brine Treatment Technology a) Electrodialysis b) Forward Osmosis c) Membrane Distillation

Pre-Concentration: Pre-concentration of brine generally obtained with membrane brine concentrators. These technologies are able to recover 60-80% of the water as per following processes shown in figure 3.

Evaporation/ Crystallisation: The next step, evaporation evaporates all the leftover water, collect it and direct it for reuse. The remaining waste then moves towards a crystallizer which boils all the water until all the impurities crystallise and filtered out as a solid as shown in the figure 4.

ZLD Evaporation and Crystallization Phase
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