Recent regulations, specifically LT2 IESWTR, are pushing water providers towards membrane filtration. Until now, there has only been one real membrane filtration option–polymeric membranes. Ceramic membranes for drinking water offer an alternative, but are relatively new in the marketplace. Developed in Japan, ceramic membranes have only been in the international municipal drinking water market for about 15 years. [Side note: If you’ve ever been backpacking and used a water filter, there is a good chance you’ve used a ceramic filter.]

This new technology is gaining traction in the United States with two ceramic drinking water facilities under design in the country. Dewberry is completing one for the Parker Water and Sanitation District near Denver, Colorado. The design is currently being finalized and will go into construction in early 2012.

What Makes Ceramic Membranes Great?

• Lifespan, lifespan, lifespan. Unlike polymeric membranes, which generally consist of a large number of very fine delicate fibers, ceramic membranes are far more resistant to breakage. In Japan, there are ceramic membrane systems that have been operating for 15 years and have experienced no breakage or membrane replacement. Warranties for ceramic membrane systems are double or triple that of polymeric membrane systems.
• Flux rate. The design flux rate (gallons treated per day per square foot of membrane surface) of ceramic membrane systems is about double that of a polymeric membrane system; meaning, less membrane material is required for filtering the same volume of water.
• Fouling. After 15 years of operation, the installed ceramic membranes are reporting no increase in transmembrane pressure (TMP). Polymeric membrane installations typically start seeing a significant increase in TMP after about two to three years of service due to irreversible fouling. Increases in TMP result in increased power costs and decreased membrane life.
• Cleaning. Because ceramic membranes are inorganic and chemically inert, ceramic membranes can handle stronger cleaning agents and require less frequent cleaning cycles.
• Recovery. Ceramic membrane systems have higher recovery (or less wasted water) than polymeric membrane systems because they require less frequent backwashes.
• Operations and durability. Ceramic membranes don’t have issues with polymers like polymeric membranes and, in some applications, allow for direct filtration.

What is the Downside of Ceramic Membranes?

The upfront cost. Capital costs for ceramic membranes are double that of polymeric membranes. But, operationally, ceramic membranes are less expensive; they require fewer chemicals, lower power costs, and have a much longer lifespan before replacement is needed. When compared to a life cycle costs analysis, polymeric and ceramic membrane systems are similar. In the future, as this technology becomes more widespread, capital costs of ceramic membranes will likely drop. If you should have any questions regarding ceramic membranes, please contact [email protected].