Zero Liquid Discharge Plants ( ZLD Plants )

Zero Liquid Discharge Plants ( ZLD Plants )

Zero Liquid Discharge is a water treatment process with a goal of recirculation of all of the possible water back to the process with zero liquid waste. The ultimate treatment process has zero or nearly zero adverse impact on the environment.
Pre-treatment - reducing TSS, COD, Turbidity to filter out particle impurities or precipitation of sparingly soluble compounds to allow additional treatment.
Concentration of dissolved solids - by membrane technologies, either by a combination of reverse osmosis (RO) with electrodialysis (EDR). The way of concentrating RO brine by EDR. Or single step electrodialysis. Using these technologies to concentrate the stream we can achieve more than 98 % of recovery.
Thermal treatment - the last step is usually consisting of Evaporator/Crystallizer to generate solids. Final evaporation of remaining water for re-use together with precipitation of solid waste for disposal in a controlled landfill or to be sold as a valuable product (pure NaCl Na2SO4 etc.)

Benefits:

ZLD Treatment Process Stages Stage 1
Preliminary Treatment
Effluent Screening Process
Oil Removal Process
Effluent Mixing Process
PH Correction Process

Stage 2
Electrochemical Coagulation And Flocculation Process
Primary Sudge Settling, Treatment Process.
TSS, Colour & Associated BOD/COD Removal Process
Hardness & Heavy Metals Removal Process.

Stage 3
Biological Treatment Process
Secondary Sludge Settling Process.
Sludge Treatment Process
BOD & COD Removal Process.
Stage 4
Depth Filtration/ Polishing Process
Polishing Of TSS, SDI, Color, Turbidity, Virus Etc.

Stage 5
TDS Removal Process.
Salt Crystallization Process.