2016 AMTA/AWWA Membrane Technology Conference Wrap

Ceramic Membranes the Hot Topic

Ceramic membranes seemed to be the hot topic of this year’s AMTA/AWWA Membrane Technology Conference, with a dedicated session of presentations and several other presentations spread throughout the program. There were also at least four companies in the exhibition offering ceramic membranes or systems using ceramic membranes. The companies I saw were Metawater, Nanostone, PWN and Meiden. There may have been more, but I didn’t have a lot of time to thoroughly walk the show floor this year.

After a lot of fascination with ceramic membranes in the U.S. for at least the past 10 years the technology is finally gaining some traction with the first large-scale system (10 MGD) starting up at Parker, CO in 2015 and another large scale installation under construction at Butte, MT. Both of these systems will be using Metawater’s ceramic membrane.

Reuter-Hess Water Purification Facility, Parker, CO

Everyone loves the performance of ceramic membranes in terms of strength and cleaning tolerance – it is much more forgiving than polymeric hollow fiber membranes. But the economics have been the obstacle with capital costs very high, even taking into account the projected long life of the membranes. Perhaps with the introduction of some competition, some new lower cost manufacturing methods and the ability for OEMs to buy ceramic membrane modules to build their own systems, much like the direction the polymeric hollow fiber MF/UF market is going, ceramic membranes will become a lot more cost competitive with polymeric membranes.

Not all Ceramic Membranes are the Same!

I also learned at the show that not all ceramic membranes are the same and therefore the benefits provided vary.

Metawater:

The ceramic membrane I think most of us are familiar with is Metawater’s, who probably has the most and longest operating municipal installations (initially as NGK), mostly in Japan, and now will have their membranes in the first two large US systems. I covered some of the history of NGK/Metawater in a previous post several years ago. Since I wrote that post, Metawater has split its ties with Kruger and is going direct to market selling complete engineered ceramic membrane systems. These membranes are manufactured from aluminum oxide as a complete monolithic ceramic element complete with feed tubes and permeate conduits (see previous post for a more detailed description). Each of these ceramic elements are encased in a stainless steel housing, allowing these membranes to withstand extreme temperatures and chemical exposures and therefore the ability to be used in some pretty dirty applications because they can be cleaned with almost anything. The membranes also supposedly will last forever – at least 20 years.

Metawater Ceramic Membrane Element

PWN Technologies:

Based in the Netherlands, PWN sources its ceramic membranes from Metawater but rather than putting these in individual housings, PWN combines the elements in a CeraMac® block of up to 192 elements in a single stainless steel vessel. The vessels look like large circular cartridge filter housings (or pressure cookers). The membrane system has all the benefits of the Metawater ceramic element and PWN says it has a lot smaller footprint and is more economical with the elements all bundled on a single housing. Like Metawater, PWN is also selling complete membrane systems. The CeraMac system certainly looks a lot different to your typical membrane plant and I am not sure how U.S. regulatory authorities would feel about having so many elements in a single vessel for integrity testing for drinking water applications. I know Metawater/PWN will say that integrity testing is not an issue because there will never be a break, but that will be a hard one to get past the regulators.

CeraMac Vessels with Multiple Ceramic Membrane Elements

Nanostone Water:

A relatively new player in the ceramic membrane market, Nanostone has taken a different approach in developing a lower cost ceramic membrane, with a goal of being closer in capital cost to polymeric membrane systems and not relying as much on the long membrane life as Metawater and PWN for competitive 20-year or longer lifecycle cost comparisons against polymeric membranes. Nanostone’s business model is also to just sell their ceramic membrane modules to OEMs who build membrane systems.

Segment of a Nanostone Ceramic Membrane

Nanostone’s ceramic membranes are manufactured as flat sheets with multiple rows of feed tubes. These flat sheet segments are incorporated into a PVC pressure housing, similar to that used for polymeric hollow fiber membranes. The segments are ‘glued’ together at each end using a potting material similar to polymeric hollow fiber membranes. The ceramic membrane module looks very similar to a polymeric hollow fiber membrane module and Nanostone is looking at the potential to use these modules in Universal MF/UF racks designed for polymeric hollow fiber membrane modules.

Ceramic Segments Potted Together

Nanostone Ceramic Membrane Module

I can see how this ceramic membrane will be lower cost with the manufacture of flat sheets rather than more complex circular ceramic elements and with the use of PVC housings rather than stainless steel. Header piping for the modules can also be PVC or HDPE rather than stainless steel. However this lower cost comes with some strings attached. Because of the potting of the ceramic segments and the PVC housings, these modules cannot withstand the extreme temperatures and chemical exposure of the Metawater/PWN elements, so probably can’t be used for the same ‘dirty’ applications that require extreme cleanings. While the membrane itself is ceramic and I assume will last as long at Metawater’s, will the potting last as long as the membranes? In my initial assessment, for a robustness ranking, I would place the Nanostone ceramic membrane above the polymeric hollow fiber membranes but below Metawater’s. So you get what you pay for. Nanostone is still optimizing aspects of the module design, including the potting, so in the future they may rise further up the robustness scale. I do like the business model of selling the modules to OEMs who will be able to build the systems more economically than I think Metawater or PWN can.

 

Meiden, who has a flat sheet ceramic membrane, was also was exhibiting at the show. These immersed flat sheet ceramic membranes operate as outside-in membranes.  The main application for these membranes is as MBRs and they would have all the robustness advantages over flat sheet and hollow fiber polymeric membranes used in MBR applications.

 

Other 2016 MTC news:

Probably next hottest topic at MTC was Universal/Open Platform MF/UF systems where there was also a dedicated session plus a few other presentations in the program. Since the 2015 MTC, there have been two large scale Universal UF systems start up at Clifton, CO (H2O Innovation) and Santa Barbara, CA (Wigen Water Technologies) and presentations on these systems were presented by Carollo and CDM Smith the respective design engineers.

 

The other interesting development was seeing Metawater and Aqua Aerobics with a combined booth. I wasn’t aware at the time that Metawater had acquired Aqua Aerobics with the announcement only a few weeks before the show. Aqua Aerobics had been promoting UF systems using BASF/Inge’s Dizzer multi-bore PESM membranes which are likely the most robust of the polymeric membranes on the market. I don’t know if this acquisition was for the U.S. engineering and manufacturing capabilities and sales network of Aqua Aerobics or if Metawater is looking to be positioned as providing the most robust of membrane systems, both ceramic and polymeric, or both. I will be interested to see if Metawater now starts promoting membrane systems using the Dizzer module.

As usual, there is never a dull moment at MTC and 2016 was no exception. It will be interesting to see what happens in the next 12 months and what the big news will be at Long Beach, CA in 2017. Here are my predictions:

• Ceramic membranes continue to gain steam
• Reuse, Reuse and more Reuse in California as El Nino does not deliver the needed moisture (First DPR system in CA announced?)
• Some consolidation amongst membrane OEMs as larger companies try to get in on the fast growing membrane market