Zero liquid discharge - a topic for the future
Given the shortage of water resources and the increasing costs for water treatment and waste water disposal, the demand for new recycling technologies is rising.The subject of reducing waste water volumes to the point where waste water can be avoided entirely, as well as the multiple use of treated waste water, is the most discussed topic in water management in the steel industry.
At the same time, ‘zero liquid discharge’ (ZLD) concepts are being considered for individual branches of industry for a variety of reasons. When it comes to their implementation, however, priority is given to economic factors. The degree of implementation depends on the economic and ecological boundary conditions.From the treatment of the available water using measures integrated into the production process – up to waste water treatment – ZLD applies to the entire process chain.
ZLD – What is it?
Zero Liquid Discharge is a process that is beneficial to industrial enterprises as well as to the environment because it cuts down on expenses and no effluent - or liquid discharge - is being generated.
The target ZLD is reached by:
- Systematic and consequent recovery of water from effluent
- Separation by evaporation of water/ wastewater in evaporators, crystallizers and condensate recovery.
- Conversion of liquid elements of wastewater into disposable/ reusable solids, such as sludge, salt
ZLD solution with conventional procedure
ZLD – Example
Wastewater treatment at a tin plate production facility
ZLD System
ZLD systems employ the most advanced wastewater treatment technologies to purify and recycle virtually all of the wastewater produced.
Also, zero liquid discharge technologies help industries to meet discharge and water reuse requirements, enabling businesses to:
- Treat and recover valuable products from waste streams.
- Better manage processed water.