Brine management via reverse osmosis-based technologies: Energy consumption, performance limits, economic...

Area of Science:

• Environmental Science
• Chemical Engineering
• Water Treatment Technologies

Background:

• Brine management is a critical challenge in desalination, especially with increasing salinity of waste streams.
• Existing technologies face limitations in efficiently treating high-salinity brines, impacting operational costs and sustainability.

Purpose of the Study:

• To comparatively assess the performance of advanced reverse osmosis (RO) technologies and mechanical vapor compression (MVC) for treating saline brines.
• To identify the operational limits and economic feasibility of low-salt-rejection RO (LSRRO), high-pressure RO (HPRO), osmotically assisted RO (OARO), cascading osmotically mediated RO (COMRO), and MVC across a wide salinity range.

Main Methods:

• Performance evaluation based on water recovery, specific energy consumption, and levelized cost of water (LCOW).
• Comparative analysis of LSRRO, HPRO, OARO, COMRO, and MVC across varying brine concentrations (up to >4 M).

Main Results:

• Membrane-based processes (LSRRO, HPRO, OARO, COMRO) are efficient at moderate salinities (<1.2 M) with ≥60% recovery.
• OARO and COMRO maintain stable performance up to ~2 M, while HPRO and LSRRO decline sharply.
• At higher concentrations (2-4 M), only OARO and COMRO are viable with ~25% recovery.
• For hypersaline brines (>4 M), MVC is the only option, despite higher energy consumption (15-25 kWh/m³).

Conclusions:

• Salinity dictates the optimal technology: LSRRO/HPRO for moderate, OARO/COMRO for high, and MVC for extreme hypersalinity.
• Results offer practical guidance for technology selection based on feed salinity and operational goals.
• Development of hybrid and renewable-energy-integrated systems is crucial for sustainable high-salinity brine management.