2016 WateReuse Symposium: Big Focus on Obtaining Pathogen Log Removal Credits for MBRs

Possible Threat to Microfiltration/Ultrafiltration in Reuse Applications

One of the most interesting topics for me at the 2016 WateReuse Symposium in Tampa, September 10-13 was the research into getting pathogen log removal credits for Membrane Bioreactors (MBRs). If granted, this could potentially be a major disruption to the use of Microfiltration/Ultrafiltration in many Advanced Purified Water (APW) projects and a significant boon for the use of MBRs.

In California, for secondary treated wastewater to be approved by the EPA State Water Resources Control Board Division of Drinking Water (DDW) for indirect potable reuse, subsequent treatment must achieve 10 log removals of cryptosporidium and giardia using treatment processes with pre-approved log removal credits. Currently, MBRs do not receive any log removal credits for pathogen removal and even though the MF/UF filtered effluent from MBRs is suitable for feeding a Reverse Osmosis system, if the objective is to produce APW for direct or indirect potable reuse, a separate MF/UF treatment step is required to obtain the necessary log removal credits. A typical APW treatment train using membranes therefore must include MF/UF [4 credits], RO [1-2 credits] and Advanced Oxidation Processes (AOP) [6 credits] providing 11-12 log removal credits for crypto and giardia. While the membranes used in MBRs will certainly provide removal of pathogens, the lack of an approved on-site test method to quantify the removal is preventing this process from obtaining removal credits from the regulatory authorities.

 
Presentations from Erdal (1) and Salveson (2) described studies that showed MBRs can provide log removals of protozoa of at least 3 which would be enough to achieve the required 10 log removals for IPR in combination with RO and AOP. These removals were based on actual analyses for pathogens in the influent and effluent of existing MBRs. The problem is coming up with an integrity test to verify the membranes are providing a given log removal. Pressure decay tests used for DITs on potable MF/UF systems do not work for most MBR configurations which are designed for lower operating pressures. Turbidity or particle counts appear to provide the best correlation with log removals but it probably will take some time before the regulatory authorities approve an integrity test method to allow MBRs to get formal log removal credits for pathogens.

With a lot less new surface water drinking water projects these days, APW is probably the biggest market for MF/UF systems, at least in the thirsty Western US. The implications of MBRs obtaining a log removal credit of at least 3.0 are pretty obvious. For APW projects where MBR effluent is the feed water, MF/UF treatment will not be required. For new waste water treatment plants that will also provide APW, MBRs would allow replacement of the secondary clarifiers from a conventional activated sludge (CAS) plant as well as the MF/UF treatment step of the APW process.

For most large APW projects, secondary wastewater is sourced from existing CAS treatment plants, so there is no need for MBRs, and this will still be a big market for MF/UF in the future. In some cases, Tertiary MBRs may be used for nutrient removal on CAS effluent, so in these cases MF/UF would not be needed. Overall though, I don’t think log removal credits for MBRs will significantly reduce the market potential for MF/UF in APW projects due to many of the larger projects treating effluent from existing CAS WWTPs, but for projects  where additional biological treatment is required, which will typically be smaller projects, MF/UF will not be required.

1. Erdal, U; “Can MBR Replace MF/UF in a Potable Reuse Train – Implementation Concerns?”; 31^st Annual WateReuse Symposium, Tampa, FL, September 10-13, 2017.
2. Salveson, A; Fontaine, N; “Resolving the Final Hurdles to MBRs for Potable Water Reuse”, 31^st Annual WateReuse Symposium, Tampa, FL, September 10-13, 2017.

 

Still Confusion between Proprietary and Non-Proprietary MF/UF Systems

Are the proprietary system suppliers fuelling this fire?



 I recently attended a conference and saw a presentation from an operator of a proprietary microfiltration (MF) system who was discussing the pros and cons of proprietary and non-proprietary MF/UF systems. This presentation, which was prepared by his consultant, was totally off track and only associating non-proprietary systems with Universal/Open Platform systems. It is a disturbing trend I have seen recently where some engineers and end users believe they have two options now when considering a MF/UF System; A proprietary system where they are locked in to the OEM’s exclusive membrane (such as Pall, GE or Evoqua), or a non-proprietary system that is designed to use membranes from a number of non-exclusive membrane module suppliers (aka Universal/Open Platform/Flexible MF/UF Systems). To simplify this discussion, I am going to group all these definitions as ‘Flexible’ systems which is probably the most accurate description of a MF/UF system that can accept more than one type of module.

This perception is partly correct in that the Flexible systems are certainly provided by OEMs who do not have an exclusive arrangement with a particular membrane module manufacturer (otherwise how could they supply a Flexible system?). But, a non-proprietary system does not have to be a Flexible system. The OEMs who are offering Flexible systems (such as Wigen Water Technologies and H2O Innovation, etc.) all started out building UF systems designed specifically for membrane modules supplied by Toray, Dow, Inge, etc. These OEMs have built many more of these non-proprietary, module specific MF/UF systems than Flexible systems and still can do so if that is the customer’s preference.

Ship has Sailed for Flexible System Deniers

While the entrenched Big Three proprietary MF/UF system suppliers originally tried to fend off the acceptance of Flexible systems, that ship has sailed, with many flexible systems now being specified and built. I believe the new strategy of the proprietary MF/UF system suppliers is trying to divide the market into two options; proprietary systems and non-proprietary Universal/Open Platform systems. Then they just have to convince the customer against a Flexible system, arguing they are more complex, more expensive and larger footprint (which is baloney by the way) so that the competition from the non-proprietary OEMs goes away. That is certainly the impression I got from that recent misguided presentation and a few other discussions with engineers I have had.

Fairly Comparing the MF/UF System Options
Let me debunk the myth that Flexible systems are more expensive and have a larger footprint than proprietary systems. I have seen many bids where the proprietary systems (from all of the Big Three OEMs) have been higher in price with their standard system than OEMs offering flexible systems, so it is BS to say that a Flexible MF/UF system will be more expensive than a proprietary MF/UF system (unless a proprietary supplier tried to build one….). Also, the modules on Pall, GE and Evoqua systems have 30% to 55% less surface area than the modules being used in Flexible systems, so  even allowing for a little extra footprint to accommodate a number of these modules on a Flexible system, the footprint of the proprietary systems is still larger. When a non-proprietary system is designed for a single module, the footprint is even less.

So the takeaway here is if an end user does not see a benefit in a Flexible system, or is not comfortable with the limited operating history of Flexible systems, but wants to minimize footprint and cost, he/she should be considering a non-proprietary system built for a specific module, in conjunction with the proprietary systems – these are not mutually exclusive options! I still see some specs wanting 10 years’ of operating experience of the OEM’s MF/UF equipment. That is currently a good way to eliminate the non-proprietary OEMs where their experience with the modules on the market is only up to about 7-8 years so far (using Toray and Dow). If the customer/engineer wants to be conservative, I believe the real requirement should not only be experience building MF/UF Systems, but also years of experience with the specific MF/UF module being offered – that significantly shortens the years of experience for Evoqua and GE to less than some non-proprietary system suppliers.

This last point is a diversion from my main topic of this post, and I don’t see many specs like this anymore, but I just wanted to make the point that other than Pall with Asahi’s Microza membrane, I don’t think there is a membrane module currently on the market that has been around more than about 7 years and the next longest modules on the market are probably Toray and Dow’s which are used in the non-proprietary systems.

Biofiltration Dominates Discussion at 2016 WateReuse Research Conference

At the recent WateReuse Research Conference in Denver, I had expected much of the discussion to be around the use of membranes (low and high pressure) for wastewater reuse applications, but was surprised that much of the research focus was on biological filtration. Perhaps since there are a lot of full scale membrane systems already installed and in the pipeline for water reuse, this is starting to be considered as a more mature technology and not needing as much research. If that is the reason I think it is mistaken, but I will come back to that later in this post.

I haven’t been keeping up with recent developments in biofiltration, so I was very interested in what was presented at this conference. Around 10-15 years ago when I was working in ion exchange I recall there was interest in looking at biofiltration for nitrate and perchlorate removal from drinking water as an alternative to IX but this treatment generally wasn’t seriously considered for full-scale systems, due to the perhaps misguided concern about using bugs to treat the water when you were also trying to pull them out to protect public health. This did not take into account that many existing filters were probably operating in biological mode to some degree anyway.

Wastewater Reuse Helps Acceptance of Biofiltration

Today the landscape has changed significantly with the current drought on the west coast and the recent drought in Texas helping the public to be more accepting of direct and indirect potable reuse of wastewater and with reuse becoming an essential component of the water supply. If the public will accept potable reuse of biologically treated wastewater, acceptance of biological filtration should be a walk in the park!

Wastewater reuse has also opened up new opportunities for biological filtration, where micropollutants (MPs) not removed in wastewater plants need to be removed if the treated water is to be used for drinking directly or indirectly. In combination with pre-oxidation to break down the MPs to biologically assimable components, biological filtration can be an attractive alternative to high pressure membranes where it has a significantly lower waste volume and does not produce a saline waste, which is a considerable benefit in non-coastal areas where NF/RO waste disposal options are limited and/or expensive.

Wastewaters Ain’t Wastewaters!

There are plenty of technical articles today about potable reuse, so you don’t need to read another one from me. I do think it is important to mention that I believe the use of membranes for wastewater reuse is not yet a mature technology and is worthy of further research. We have all read a lot about Orange County Water District’s Groundwater Replenishment System that has been using membranes for decades for treating wastewater to drinking water standards and maybe some think you can just throw membranes at the end of any secondary wastewater treatment plant and start making high quality recycled water….but wastewaters ain’t wastewaters and membrane treatment is not that simple…. The quality of secondary effluent can vary significantly, from inland WWTPs with stringent nutrient removal requirements to ocean discharge WWTPs with less stringent requirements. This can result in widely varying cleaning requirements which also varies by membrane type. While there have been a lot of pilot studies on different secondary effluent sources, I haven’t yet seen a dedicated study evaluating the impact of specific secondary effluent constituents and the impact on low pressure membrane permeability and cleaning effectiveness.

Perhaps with all of the recent reuse pilot studies, this information will start to come together. Or maybe the key results will be kept from the public as a competitive advantage for those with the pilot experience, which is understandable when OEMs and/or engineering firms have generated this knowledge. This is where no-strings-attached research can help the reuse industry. After being involved in several recent pilot studies my take-away is that wastewaters ain’t wastewaters and don’t assume you can simply take the performance of a membrane at one WWTP and apply it to another.

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

 

 

 

To Bid or Not to Bid?

What to do when you are only listed to keep the preferred vendor honest
As the dust settles on the annual end-year bidding frenzy where I probably bid on a few projects that were set up for other companies and we were just making up the numbers, I wonder if there is any value in bidding when you know your company is just listed so the owner can get a competitive bid. In some cases there are benefits in putting in a bid even when you know you have no chance of being selected over a preferred supplier but at some point when you have limited resources to spread between projects you have to make the decision – to Bid or Not to Bid?

There can be a number of reasons a company/supplier may be listed in a specification but have no chance of being selected:

• Another company has a good existing relationship with the end user through previous equipment supply and the owner wants to continue to deal with this company and the service personnel rather than work with a new company. This is especially the case where the project is an expansion of a facility, but as it is a large capital expenditure, it still needs to be competitively bid.

• Another company conducted a pilot study that the full-scale equipment design is based on, has developed a good relationship with the owner and was able to help write the specifications for the full-scale system. These specifications may require certain system features that are proprietary to the other company or difficult and costly for you to provide. This includes components that you may not typically use, so you do not have good OEM pricing.

• A service center must be within a certain distance of the project site or response times are required that can only be provided by one of the companies listed.

• The amount of information required to be submitted with the bid (detailed drawings, custom operating protocols, etc.) cannot possibly be provided by the bid date unless you had been working on these prior to the bid being advertised.

• Even though you are listed as an approved supplier, the first time you hear about the project is when it is advertised…

Even if you recognize you are just making up the numbers for one or more of the above reasons, there can be a number of reasons why you may still want to put in a bid as follows:

• It is an opportunity for the owner and consulting engineer to see the quality of your work through your proposal and the references provided. This may help you to be more seriously considered when the next project comes up.
• By putting in a bid you may be sent a post-bid tab with all bid prices listed and other competitive information that you can use to your advantage next time (you may also not want to give away that information if you don't think you can win).
• The preferred supplier may get overconfident and greedy and provide a price way over budget resulting in your proposal being considered seriously. Along the same lines, the preferred supplier and owner may not be able to agree on contractual terms forcing the owner to look for an alternative.
• The bid may come at a time when the other companies listed are very busy and there is not the incentive for them to put in a competitive bid.

The last two points are like playing the lottery and you do not want to be hoping for these scenarios every time you bid. I think the first two points are a better reason for bidding, as you have no false hopes and are working to build sales in the long term rather than hoping for a lucky windfall.

I am coming from the perspective of selling large custom capital-built equipment where a lot of engineering effort and time is required to prepare a bid proposal. So when it appears the specification is written around an alternative supplier, you really have to decide if it is worth diverting these valuable resources from existing projects that you have orders for, or from bids where you know you have a better chance of winning. I have worked on bids where the owner or owner’s engineer has assured me that there is no preferred bidder and everyone will be considered on their merits, then when the bid award notice comes out there is no pricing listed, the company it appeared was preferred is selected and you get some patronizing statement that the proposals were very close but in the end the owner went with the company they were familiar with or had closer service personnel, or some sort of subjective reason that is difficult to argue against.

Don’t get the impression that I resent the owner or their engineer for trying to get us to make up the numbers and bid. I get it that for public entities they have to have at least 2 if not 3 bidders, so the customer will encourage other bidders even if they have a preferred company in mind. As a manufacturer you always want to be in the position of having the specs written around your equipment and you should be in that position at least 25% of the time or you won’t win many jobs and will spend a lot of wasted engineering time on failed bids… The question is, when you know you are not the preferred supplier, do you bid or not? You then have to go through the possible upsides of putting in a futile bid listed above. There is also the possibility that there truly in not a preferred supplier and the engineer/owner has used a generic specification that may not suit any bidders perfectly. You then have a good chance in winning the job if the other bidders put in a halfhearted effort on their proposals. I see that in possibly one out of ten bid specs. The challenge is identifying if this is the case, and if you can the job may be yours for the taking.

We all have our ways to try get our equipment specified or find out if the specs are written around someone else and sometimes this works and sometimes you completely misread what you think you see between the lines. I have elected to not bid a few projects and then found out the company I thought was the preferred bidder didn’t bid either… I am still learning through the school of hard knocks how best to play the bidding game as I am sure my competitors are. I could write a lot more about this topic, but I don’t want to give away any more of my trade secrets until I retire so these can’t be used against me!