ED Smart -Technology ID
About the R&D program:
Lesico CleanTech, in partnership with Ben Gurion University and Mekorot- Israel’s national water company, is currently developing a new designed Electro-Dialysis stack that will enable us to transfer the reverse osmosis rejected waste into a highly concentrated solution, approximately 15% solid, reducing the waste volume many-fold. The ED unit will combine in a large treatment scheme minimizing concentrate volumes further treated by the WAIV (See figure below).
Product Description:
The new design concept is based on sealed modules allowing free flow of solutions within the stack and thus will reduce energy consumption and precipitates. The new design will also be based on new polymer membranes that can be sealed to each other and ion-conducting spacers to reduce polarization.
Inland desalination of brackish water can be further promoted if a viable solution for the reduction of the volume of the concentrate can be achieved economically. A near-ZLD concept using Electro dialysis for further treatment of brine solution derived from brackish water desalination by Reverse Osmosis followed by enhanced evaporation method which is already practiced worldwide is under investigation.
Technology Rationale:
Desalting processes separate water molecules from the feed water, resulting in a concentrate (or brine) stream that is more concentrated than the feed water. A higher recovery (volume ratio of product to feed water) is preferable because it results in more product water (greater production), reduced feed water (less resource usage), reduced wastewater (less treatment and less disposal volume), and consequently multiple cost savings.
As the recovery ratio increases, however, the concentration of the dissolved ions in this stream becomes high enough to form perceptible compounds such as calcium carbonate, calcium sulfate, silicate, and barium sulfate.
These precipitates form a scale on process surfaces such as membranes, flow channels, and heat transfer surfaces, reducing the process efficiency and limiting the process recovery.
The new designed modular ED membrane stack is aimed to enhance overall recovery and reduce concentrate volume- a key to the future success of membrane-based technologies.
Inland desalination of brackish water can be further promoted if a viable solution for the reduction of the volume of the concentrate can be achieved economically.
Addressed Market Need:
As water demand increases and freshwater sources are becoming increasingly stressed, there is an impetus for water utilities to treat impaired water sources such as brackish groundwater, irrigation return water, and seawater to meet increasing demands. The efficiency of desalination technology used to treat such waters has improved over the last decade, but there are currently certain key limitations that need to be addressed to make this technology more cost effective.
A key issue that stands out is the low productivity or recovery that results in a large volume of concentrate, high-energy use, and relatively high treatment costs.
Currently the recovery from the conventional application of desalting processes, including reverse osmosis (RO), electro dialysis reversal (EDR), and thermal evaporation processes, is limited. Some 20 to 50 percent of the feed stream is wasted as byproduct or concentrate.
The new ED membrane stack will enable a near zero discharge desalination with minimal burden on the environment.
Target markets for the new ED are desalination (including hybrid systems with RO membranes), Electro Deionization (EDI) for ultra-pure water and concentrate volume reduction.
Competitive Advantages:
- Reduced equipment costs
- Reduced energy consumption
- Precipitates proof
- Ease of operation and maintenance