Brine Management System for Achieving Zero Liquid Discharge

NU 2018-500

Inventors

Youhua Jiang
Neelesh A. Patankar
Kyoo Chul Park*

Short Description

A brine management system that achieves zero liquid discharge with various desalination approaches.

Background

With an increased global demand of fresh and clean water, desalination methods like reverse osmosis, multi-stage flash, and membrane distillation methods, have continued to be developed despite their high cost.  A critical downside to desalination, however, is the by-product of brine discharge which causes environmental and ecological stresses like changes in water salinity, alkalinity and temperature, ultimately impacting aquatic flora and fauna.  Achieving a zero liquid brine discharge for existing desalination methods could be a major breakthrough.  Until now, complete evaporation of brine has not been successfully achieved, largely due to the need for tremendous levels of thermal energy.  Solar thermal evaporation of brine is one of the most energetically-efficient approaches and may offer a potential opportunity if adopted.

Abstract

Northwestern researchers have developed a new system technology that enables the successful removal of all brine liquids, an undesired and toxic by-product of desalination.  In the first stage, brine is atomized, taking on a form that is more efficient for evaporation.  The brine fog droplets then flow through an evaporation system that is heated at high temperatures with concentrated solar energy.  Remaining dry salt particles are then captured by a filtration system, while pure water, captured as hot water vapor, moves through a low temperature condensation system, cooled by natural or forced convection of air or liquid, such as sea water.  Northwestern researchers have already demonstrated a proof of concept and feasibility of this technology through testing a wide range of salinity from zero to the maximum, reaching the solubility of sodium chloride in water.  They found that the addition of a small amount of surfactants improves the brine fog generation rate, leading to faster evaporation of brine. This technology offers a game-changing solution to brine production which plagues desalination or water purification efforts.

Applications

• Desalination plants and water purification systems
• Waste water treatment
• Salt separation/generation

Advantages

• Enhances faster evaporation respect systems with bulk brine
• Lowers energy consumption: solar energy is used to evaporate brine fog droplets.
• Enhances the fog generation rate by using various atomization methods and surfactants

IP Status

US and International patent applications have been filed.