My Five and a Half Best Membrane Developments of the Decade

In January, Global Water Intelligence published the ten biggest water technology breakthroughs and busts of the past decade and many of those whose companies were mentioned on the listed breakthroughs (including myself) were happy to pass on the list. Just for fun I thought I would list my top five and a half membrane technology breakthroughs of the past decade, a number of which were on GWI’s list, and provide my reasoning. I won’t list my busts so I avoid getting bombarded with complaints, especially with the Membrane Technology Conference in a week, although if you look at my post from last February you will see a few I mentioned that are on GWI’s list.

Part of GWI's List

In no particular order, here is my list:

1/ Universal Rack for Ultrafiltration/Microfiltration Membranes

I might be biased here but this concept has really taken off in the last 6 years, where the availability of a number of similar UF/MF modules from different suppliers has allowed some OEMs to develop racks that can accommodate these modules and for the first time allow competitive bidding for the replacement modules. See a number of my pervious posts describing this concept in more detail. What makes this development sustainable is that it is not proprietary as a number of OEMs have developed these racks, which allows competitive bidding to supply these systems, which is very attractive to municipalities. As noted by GWI, H2O Innovation and Wigen along with Suez were the pioneers of this concept. While Suez was probably the first to market their rack, they are a minor player in this market in North America. GWI listed this development as #5.

2/ Retrofit UF/MF Modules

Hot on the heels of the development of the Universal Rack has been the introduction of retrofit UF/MF modules; exact replicas of existing modules in terms of dimensions, so they can be directly swapped out. Pall’s Microza module has been the main target of these replicas with the first replacement developed by Scinor followed by replacements developed by Dow/Dupont and Toray. Scinor has also developed replacements for Toray, Dow and Memcor (now Dupont) modules. Another target has been GE/Suez’s MBR membranes with several replacement modules on the market. Pall, Evoqua and Suez have been targeted due to their large installed base. With the development of retrofit modules and Universal Racks, the days of making money on replacing UF/MF modules are disappearing.

3/ Multibore UF Membranes

This was listed by GWI at #9. These are inside-out PES membranes which historically have had a bad reputation in the US due to integrity issues, but these multi-bore inside-out membranes manufactured by Inge/BASF (now Dupont) are different and are very tough and rarely break and have very high permeability. Adoption has been much more widespread outside the US, but there have still been a good number of municipal and industrial systems installed here in the past several years. Use on Universal racks is more limited because these racks are usually designed for outside-in PVDF membranes. Inge’s module has also had some success as a replacement option for Norit/Pentair inside-out modules. Dupont’s recent purchase of Inge from BASF could help increase the marketing reach of this product.

4/ Nanostone Ceramic Membranes

Nanostone’s ceramic membrane module is different from other ceramic membranes in a number of ways. The membrane is contained in a PVC housing, just like a polymeric membrane. The cleaning and backwashing regimes are also similar to polymeric membranes which has allowed Nanostone to retrofit these modules at installations using existing Pall, Dupont and probably other modules. As a result, Nanostone likely has quickly accumulated the largest number of ceramic membrane installations in the US. Other players such as Metawater with conventional stainless steel housings still only have a handful of US installations. While everyone likes the durability of ceramic membranes, the high cost has inhibited widespread adoption. Nanostone’s innovative method of module construction has helped reduce costs, but these are still a lot higher than polymeric membranes per square foot of membrane area and Nanostone’s installations are usually where polymeric membrane fluxes are low due to challenging water characteristics that don’t impact the ceramic membranes as much. GWI did not list the Nanostone membrane, possibly because it is still relatively new on the market and not proven as a long-term technology yet.

5/ Closed Circuit Desalination (CCD)

This is my lone high pressure membrane breakthrough where this market has been commoditized for some time. Desalitech (now Dupont also - do you see a trend here?) has certainly had success in rolling out this proprietary high recovery RO process, with a lot of industrial sales and some municipal sales. I don’t think this is a widespread replacement for conventional two and three-stage RO systems but rather a niche application where feed characteristics such as high silica or organic carbon (of wastewater origin) allow the CCD configuration to get higher recoveries. This was #7 on GWI’s list.

5.5/ Non-Exclusive MF/UF Modules

This isn’t really a new product or technology development but the introduction of new MF/UF modules in the past 10 years is worthy of mention as this has helped develop the market for the Universal UF rack, which would not be possible if a number of good quality modules were not available to OEMs. Module suppliers include Toray, Dow/Dupont, Hydranautics, Inge/Dupont, Scinor and Memstar. This has loosened the grip the previous Big Three MF/UF system suppliers had on this market with their proprietary systems.

I know there have also been some great breakthroughs with MBR membranes and systems but that is not my area of expertise.

The comments and opinions in this post are my own and not that of my employer.