Recent development in high-salinity wastewater treatment technologies for zero liquid discharge

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Chemical Engineering

Background:

• High-salinity wastewater presents significant environmental challenges due to high osmotic pressure and complex composition.
• Urgent need for safe, resource-efficient treatment methods within a zero-liquid-discharge (ZLD) framework.

Purpose of the Study:

• To systematically review mainstream and emerging technologies for high-salinity wastewater treatment.
• To analyze technologies across pre-treatment, core treatment, and post-treatment stages.
• To identify future research directions for improved efficiency and sustainability.

Main Methods:

• Comprehensive literature review of existing and novel wastewater treatment technologies.
• Analysis of membrane-based processes (RO, HPRO, OARO) and thermal concentration methods.
• Evaluation of emerging technologies (humidification-dehumidification, solar distillation) and hybrid systems.

Main Results:

• Reverse Osmosis (RO) and its derivatives are mature for salinities up to 120 g/kg, with energy consumption of 3-22 kWh/m³.
• Conventional thermal concentration handles full salinity range (40-250 kWh/m³), benefiting from advanced materials.
• Emerging methods face efficiency limitations, while hybrid processes and improved pre-treatment show potential.

Conclusions:

• Integrated "materials-energy-process" low-carbon strategies are essential for high-salinity wastewater management.
• Advancements in membrane performance, corrosion-resistant materials, and intelligent control are critical.
• Moving beyond single-path optimization towards holistic ZLD solutions is recommended.