Sunday, December 25, 2011

Microfiltration & Ultrafiltration Integrity: Don’t believe breakages happen!

Myth spreads that a certain amount of MF/UF Fiber Breakages are acceptable...

I’m back, and I’m mad! I started this blog with the intention of being as informative and impartial as possible on water technology topics, but my New Year’s resolution is to spice it up a little and forget about being PC. I am fed up with the perceived mystique around building a reliable MF or UF system for drinking water applications after just losing out to Pall on a UF project because my company was considered ‘not qualified’ to have our price considered. I have to hand it to the ‘big three’ MF/UF manufacturers, Pall, Siemens/Memcor and GE/Zenon. They have certainly done a good job in convincing consultants and owners that manufacturing a MF/UF system is so complicated that only established players in the market should be considered. They were the first to get established in the market, so they have the right to leverage that advantage, but they can only pull the wool over the industry’s eyes for so long! There are now some bloody good alternative UF membranes out there on the market, better than most of the established products, and the sooner this is realized, the sooner the end users will reap the benefits.

In an interview for the project we were recently unsuccessful on, the owner’s consultant (from one of the biggest municipal engineering firms in the world) implied that because we were a small firm and did not have standardized UF system designs like our larger competitors, our custom designed systems would potentially have reliability issues because we did not have experience with the exact same system configuration operating in the field. He then went on to question why we did not have a large list of exceptions to the specification we bid to. The reason we didn’t have exceptions is because we bid with a design that matched the spec rather than tried to squeeze a standard UF skid design into their spec – duh! The big membrane companies have done a good job in brainwashing the engineers on why a standard design is better than a custom system for small skid mounted applications. The reality is that the big firms cannot cost effectively custom design a small skid mounted UF system and the only way they can be successful on these smaller projects is to have the smaller custom design firms disqualified. Good luck in now trying to put that square peg in a round hole and getting an off-the-shelf design to operate as specified!


Hollow Membrane Fiber Breakage
 Why then is our small company successful in winning similar sized NF and RO projects with the same global engineering firms? Is it because with NF and RO considered more of a commoditized market, the engineers assume these are simpler to build than MF/UF systems? As a company that manufactures UF as well as NF/RO systems, that is complete BS! UF systems are actually simpler to manufacture. The only challenge has been getting a UF membrane module that will not fail integrity tests. Two of the major MF/UF system manufacturers have had significant problems in recent years with membrane breakages, but they have done a very good job in convincing the market that some membrane fiber breakages are par for the course. Poppycock!! There are now UF membranes on the market from Toray and Inge that have no recorded fiber breakages to date, including systems we have built using these membranes. It is the established companies that manufacture their own proprietary MF/UF membranes that are having the integrity issues and want the market to believe that some level of membrane fiber breakages is inevitable (Stratton, et. al.). These companies are probably scared to death at the more robust UF membranes such as Toray’s that have entered the market and are available to OEMs (see Municipal Ultrafiltration Heads Towards Commoditization).

The large MF/UF system OEMs have largely left the packaged NF/RO market because they are not cost competitive, especially for skid mounted systems. Ultimately, they will not be competitive in the skid mounted UF market either – they actually aren’t currently cost competitive, but are surviving in this market through scare tactics to keep owners and engineers from considering the more cost effective alternatives. Sooner than you think, the time will come when at least two of the ‘big three’ will be squeezed out of the skid mounted MF/UF market. The big winners will be end users who will get higher quality UF systems at a much lower price.

References:
Stratton, Richard and Chang, Yujung (2011), “Membrane Fiber Breakage: Case Histories, Probable Causes, and Possible Solutions”, 2011 American Water Works Associations Membrane Technology Conference, March 28-31.

5 comments:

  1. Thank you for sharing to us.Please one more post about that..
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  2. Hi Michael...in your experience, is RO worth the water losses when MF or UF and a good UV sterilizer are in place?

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    1. Sorry, I missed your question last month. I would only use RO where removal of dissolved salts is required (which MF and UF can't remove) due to the higher energy cost and water losses from RO. I actually see RO and MF/UF used for different purposes, so you are not really selecting one over the other. MF/UF is for particulate removal, RO for dissolved salts removal. RO cannot be used for particulate removal. If you are treating a surface water and want to remove say hardness or TDS, you need MF/UF pretreatment prior to RO to first remove the turbidity - so in this case MF/UF is pretreatment. Does that answer your question?

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