Membranes by Application:
Organic Fouling Resistant Membranes
AR103 and CR61 provide stability in high pH environments where aggressive cleaning with caustic solutions is needed along with organic material fouling resistance. These membrane chemistries have been used for more than 50 years for applications in the food and beverage industry, most prominently in the demineralization of cheese whey,
Standard Water Membranes:
Veolia's AR204 and CR67 membranes have the widest total footprint globally. They have been the primary membrane used in water desalination electrodialysis applications for 30 years. They are a cost-effective, scaling resistant membrane with resistance to chlorine, are NSF approved, and in water desalination applications can have a lifetime of 15 years or more. They can also be used for low organic fouling process applications.
Bipolar Membranes:
Veolia's Bipolar membranes are used in electrodialysis applications where salts are converted into acid and caustic product streams or where pH of process solutions can be adjusted. These membranes have two layers; one cation-selective and one anion-selective layer. The AR103 and CR63 are the primary options for the layers of the bipolar membrane.The anion layer is treated with a catalyst to aid in the water splitting function of the membrane.
Acid-Blocking Anion Membranes:
In 3C-BPED applications, where separate acid and base streams are generated, the use of standard anion exchange membranes limits the concentration of acid that can be achieved due to the free movement of protons (H+) from the high concentration acid stream through the anion membrane back into the dilute salt stream. Veolia has developed two types of acid-blocking membranes that limit this transfer and allow for higher concentrations in the acid and base stream and/or allow operation at a higher current efficiency. The AR118 chemistry is specifically designed for multi-valent anions like sulphate, the AR119 chemistry is most suitable for mono-valent anions like chlorides.
High pH Anion Membranes:
Veolia's AR908 membrane is a versatile anion exchange membrane that has been used by some of our largest EDR installations for drinking water and wastewater desalination. It allows for cleaning with high pH solutions which the AR204 does not. However, its resistance to chlorine is lower, so there can be a tradeoff depending on the specific application. The caustic resistance also makes it a cost-effective alternative to the AR103 membrane for process demineralization applications.
Membrane Innovation:
Nonwoven Cloth Membranes:
To improve performance of our ion exchange membranes, we discontinued use of a woven acrylic cloth and replaced it with a nonwoven polyester cloth. First, the nonwoven cloth membranes have lower electrical resistance. This means that when used, the voltage required to achieve a target product TDS can be lower. This can result in lower power consumption by the ED or EDR plant. Since the membranes are made of a nonwoven cloth, they will not generate “strings” hanging on the exterior of the stack as the edge of the membranes become dry, as happens with the use of woven cloths.
Thinner Membranes:
As part of the new generation of ED and EDR stack designs, Veolia created the V series with thinner membranes that fit in our recessed spacer design to further improve electrical resistance for more efficient ED and EDR operation. These membranes can also be used in existing MK4 stack hardware to provide lower power consumption and/or expanded capacity. 750 cells of membranes will fit in the space that 600 cells of the thicker membranes occupy.
