Pictures of the Future Spring 2005
Elements of Life – Ultrafiltration Start-Up
Purification with Nano Pores
Start-up inge AG plans to use its innovative technology to become the leading supplier of ultrafiltration modules. Siemens Venture Capital is supporting its efforts.
inge AG technology uses capillaries with nano pores to make ultrafiltration economical for everyday uses
Nanotechnology is playing an important role in the purification and sterilization of drinking water. When water is pressed through membrane pores that have a diameter of 15 nm, all solid particles, viruses, bacteria and spores are left behind. This process—known as ultrafiltration—is currently one of the most reliable ways to disinfect water without having to use chemicals, such as chlorine. Start-up inge AG, which is co-financed by Siemens, has made a decisive improvement to this technology.
The goal was to make ultrafiltration more economical and more suitable for everyday use. Filters that combine several thousand capillaries into a module have proven effective for treating large amounts of water. Each capillary is a hollow fiber similar in appearance to a straw. The fiber wall serves as a membrane, and the primary material in the capillaries is polysulphone, a type of plastic. The largest ultrafiltration facilities today produce about 3,000 m³ of clean water per hour, enough to supply half a million people or a large power plant. Water is pumped at low pressure through the capillaries in the module, after which it escapes through porous side walls. The particles left behind form a residue that must be rinsed away at regular intervals. This is done by reversing the flow for a few seconds, putting significant strain on sensitive membranes. The result is that capillaries in systems equipped with conventional technology often break.
Energy-Conserving Filtration. This is where inge AG comes in. Founded in 2000 in Greifenberg, Germany, the company has developed hollow fibers, each containing seven capillaries combined into a membrane fiber (multi-bore technology). The membrane fiber’s interior walls form the active filter layer. Membranes are produced by using a specially developed polyether-sulfone material to create a foam-like support structure.
The manufacturing process is controlled to ensure the membrane walls have the exact porosity desired. "The foam-like support material is porous enough to ensure it won’t inhibit water flow," says Michael Hank, inge AG’s CEO. "So there’s only a slight loss of trans-membrane pressure, which makes this material unique on the market. This property helps reduce operating costs at industrial facilities." The individual fibers are bound into membrane mats that are rolled up and fitted into a perforated interior tube, which is inserted into an exterior tube. The fibers are sealed together at both ends with an epoxy resin, as are the two jackets. "This means we don’t have to use seals that are subject to wear and tear, and the treated and untreated water are always reliably separated," says Hank.
When the system goes into operation, untreated water is first pumped into the capillaries. The treated water collects in the gap between the interior and exterior tube and is drawn off with a nozzle. Depending on the purification level desired, this water may already be suitable for drinking. If not, it goes through additional process steps such as reverse osmosis for desalinization, because salt isn’t removed by ultrafiltration. The fiber mats also have special features. "The individual fibers support one another in the lattice-type arrangement we use," Hank explains. "That’s important because they’re impacted every time we switch between filtration and rinsing. This impact would make them oscillate if they weren’t stabilized in this manner—and that could eventually lead to breakages." The arrangement also makes it possible to ensure a pre-defined distance between fibers. This makes it possible to ensure flow resistance is the same at all locations and that all capillaries are subject to the same flow pressure. inge AG is targeting the U.S., Europe and China for its new product. More than 30,000 municipal water-treatment facilities will have to be built in the U.S. alone in the next few years, and China is expanding its energy infrastructure, which requires vast amounts of very pure boiler-feed water. The new EU states in Eastern Europe also represent a growth market.
Key Innovative Technology. Siemens Venture Capital (SVC) is an investor in inge AG. "We believe the technology can offer Siemens major synergies in its core business of power-plant technology and in terms of our goal of becoming a global player in the water-treatment business," says Bruno Steis, who is responsible for investments at SVC. "inge AG—and the acquisition of USFilter—give Siemens more access to key technology." Adds Hank, "We benefit from the Siemens network, and SVC’s investment is taking us a big step closer to our goal of becoming the leading supplier of ultrafiltration technology. We’re aiming to achieve annual sales of at least 100 mill. € by 2010."
Björn Gondesen