Membrane scale-up secures factory investment

REDStack, a Dutch membrane scale-up, has secured significant investment that will accelerate the commercialisation of its ElectroMembrane Stack technology. The funding will be used to create a fully automated production line at its base in Heerenveen, ramping up output from one stack a week to 10 and the potential to reach 1,000 per year, per shift.

Investment round led by PureTerra Ventures

The investment round was led by Amsterdam-based water tech investor PureTerra Ventures, with additional input from NV NOM and Easter Technologie. The level of investment was undislosed.

Paula Gonzalez, REDstack CEO, told media: "This investment is more than just upscaling technology ¬¬─ it's about harnessing the power of disruptive technology to address water treatment, climate change, and resource scarcity. REDstack exemplifies the potential when technology and purpose unite."

Nic Pannekeet, partner at PureTerra Ventures, told media: "Since the original electrodialysis reversal (EDR) stack was designed some 50 years ago the industry has been waiting for a breakthrough in electrodialysis technology. Enter REDstack with its innovative design, extreme reduction of energy consumption, extension of membrane lifetime, reduced maintenance, and 100 per cent leak-free operation. We are very excited to bring this leap forward from traditional EDR technology to the global market.

He added: "Our investment will contribute to an automated production line, fuelling the commercialization and global impact of this game-changing technology."

REDStack membrane technology

Founded in 2005, REDstack's technology was originally developed at Wetsus. The latest investment will enable the company to accelerate the commercialisation and large-scale production of its ElectroMembrane Stack technology.

Originally developed in the 1960s, EDR stack technology is used commercially to treat brackish water from both ground and industrial sources. The technology uses electrodialysis to remove salts.

REDStack's ElectroMembrane Stack technology takes the process a step further by combining Anionic Exchange membranes (AEM), Cationic Exchange membranes (CEM), and Bipolar Membranes in its stacks to not only remove salts from the water, but also to recover nitrogen (from acidic scrubbers) and carbon dioxide (from alkaline solutions in Direct Air/Ocean Capture).

Sjouke Mulder, NOM, told media: "At NOM, we are committed to empowering innovative companies that drive impactful transitions in sustainable and smart technologies. REDStack's advancements in water technology align perfectly with our mission."

He added: "Their recent establishment in Heerenveen and strong connection to Wetsus in Leeuwarden underline the importance of collaboration in fostering sustainable growth in the Northern Netherlands. By investing in REDStack, we are enabling innovation that addresses global water challenges while strengthening the regional economy."

Optimising flow to reduce energy costs

REDStack's EDR stack technology is helping to address a number of key priorities for water treatment: reducing energy costs; and both carbon and nitrogen capture.

The stacks are able to use membranes and spacers from a variety of suppliers. They are designed using patented technology and employ 100 per cent liquid-tight, fully closed modules with 'perfect flow' distribution to avoid 'carry over' of liquids between compartments.

The optimisation of this flow distribution has the effect of reducing the energy required for ion transport, to a level the company states is two or three times less than comparable systems.

Current use and future plans

REDStack's ElectroMembrane Stack technology is already being proved in real-world environments, including on the Afsluitdijk dam in Netherlands for energy generation and CO2 capture, as well as for treating recycling paper mill effluent at IndustrieWater Eerbeek, also in the Netherlands.

Pieter Hack, founder of REDstack and representative of W&F Technologies B.V., welcomed the investment and what it would mean for the company's future: "As founder of REDstack, I am happy and proud that with this new investment from leading and renowned investors, REDstack is heading to its next phase in becoming the leading supplier of technology and electromembrane stacks for innovative and sustainable applications in the water market."