The Navajo Tribal Utility Authority has agreed to bring six wastewater treatment facilities into compliance with the federal and Navajo laws in...
Membrane suppliers find new ways to develop their product
Membrane suppliers find new ways to develop their productIn the last year, Sunil Kommineni and Jack Bryck of Malcolm Pirnie, the water division of Arcadis, met with membrane supply companies to learn about new technologies and to find out where the industry is headed. Here they discuss the latest trends in low-pressure membranes and the future of the industry with WWD Associate Editor Kate Cline.
Kate Cline: What are the current trends in low-pressure membrane filtration for drinking water?
Sunil Kommineni: Increasingly, low-pressure microfiltration (MF) and ultrafiltration (UF) membranes are being considered for smaller, 20- million-gal-per-day (mgd) and large, greater-than-20-mgd greenfield water treatment plants. The life-cycle costs for MF/UF membranes have been gradually declining over the past few years due to advances in membrane materials resulting in higher productivities and lower membrane fouling, operational experience on what works and does not work, and pretreatment selection (types and dosages of coagulants). Newer materials such as ceramic membranes are being evaluated for niche applications such as treatment of spent filter backwash water from conventional water treatment plants.
Jack Bryck: Low-pressure membranes are also being used in membrane bioreactors (MBRs) for treatment of wastewater. Large water providers are considering MBR for satellite wastewater treatment plants to conserve water and meet distributed, nonpotable water needs. The MF/UF membrane system costs are stabilizing due to increased industry experience. Because of the proprietary nature of the MF/UF systems, water providers are “wedded” to the chosen supplier. Therefore, water providers are factoring the ability to deliver service—repair, replacement parts and technical support—as one of the key drivers in the selection of a membrane supplier.
Cline: What did you learn in your meetings with membrane companies?
Bryck: Membrane suppliers anticipate continued growth in the sales and use of membrane systems globally and in North America. Membrane suppliers are conducting additional research to improve their products’ design and performance. Suppliers are paying additional attention to after-sales service and alternate project delivery methods, such as design-build and design-build-own, in the municipal market. Membrane suppliers are anticipating continued growth of 10% for the next few years.
Research and development is focusing on several things, including the development of ideal polymeric membrane fiber (fiber that maximizes permeability and recovery with minimal fouling); the development of optimal module and rack systems that are cost-competitive and easy to operate and maintain; new packing arrangements to reduce the membrane system area requirements by increasing the fiber area per area of the membrane filtration system; and more sustainable systems that use less energy, fewer chemicals and generate fewer residuals.
Kommenini: Ceramic membrane suppliers are exploring niche market areas such as treatment of high-particulate streams with minimal pretreatment (no clarification ahead of membranes). Ceramic membrane suppliers are conducting additional research to improve membrane packaging, module design/manifold and operation.
Cline: And where do you see membrane technology heading in the coming years?
Bryck: Use of low-pressure membranes will continue to increase in the municipal market due to various drivers, such as population growth, stricter regulations, impaired source waters, low space availability and high automation requirements (low manual attention). Anticipate the development of alternates to polymeric membrane fibers, such as ceramic membranes with longer life and more robustness.