IDA 2022 World Congress a Global Meeting of Desal Minds

After changes of venue and multiple delays due to the Covid pandemic, the 2022 International Desalination Association (IDA) World Congress was finally held in Sydney Australia, October 9-13. It is the first time I have been to this conference, or any truly international water conference for that matter, and it was exciting and inspirational to see the global networking and established relationships across continents and the open sharing of technical knowledge and experiences. Everyone was drawn together by a common interest in water treatment, mostly by desalination, and protecting the earth’s most natural resource, no matter the country, language or culture. I may sound a bit cliché, but I was truly moved by the spirit and sense of common cause of the conference.

What’s New is the World of Desal? Brine Mining!

The main focus of the technical program was seawater desalination but there were some interesting topics and new developments being discussed in the desal world. Most notable to me was how to handle waste concentrate and a lot of interest in brine mining. Highly concentrated brine is being seen as a potential resource for rare earth metals, including lithium. First there needs to be processes to concentrate brine higher than conventional seawater membranes and companies such as Gradient and Toyobo presented on osmotically assisted RO (OARO) processes that can concentrate brine from a seawater process up to 130,000 mg/L TDS without needing significantly higher pressures. Osmotic assistance is provided by applying a saline stream on the permeate side, which lowers the osmotic pressure difference across the membrane, allowing permeate production at feed pressures less than the osmotic pressure of the feed. There is also interest in ultra-high pressure membranes and housings for achieving higher seawater recoveries and therefore higher brine concentrations, but I think if the counterflow processes are feasible, they are a safer and probably lower energy option.

 Once you have the highly concentrated brine, you have to extract the valuable constituents and from one presentation I saw from Dr. Monsalvo from Aqualia, that involves a lot of treatment steps… So it looks to me the recovered metals would need to be very valuable to offset the high cost of extraction. With world shortages in these elements, I’m sure with continued research the extraction costs will go down making these processes more feasible. There is no shortage of research in this area! There were also many presentations looking at minimizing the environmental impact of brines, indicating the industry realizes this needs to be addressed to ensure desalination is a viable water supply solution into the future.

Wastewater reuse also had a prominent share of the program, recognizing the role of desalination in reuse applications, with several dedicated sessions and two panel discussions, one of which I was very pleased to participate on.

The IDA Water Reuse Panel I was excited to be part of

I was also very impressed with how the technical sessions and panels were all conducted in the exhibit hall in walled-off areas, so it was easy to jump from session to session or to a panel discussion without leaving the hall. Meals were also served in the same area keeping attendees together all day. This is a great model for other conferences if it is logistically possible.

I can’t say I have anything negative to say about the show. Very professional production, great technical content, great networking, awesome venue! As long as you were able to get to Sydney… 

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

Manganese Removal Ain’t Manganese Removal!

 

I was looking at specifications for a project earlier this year that had very tight targets for iron and manganese (combined target of >0.06 mg/L) but there was no pilot data to back up that these targets were achievable. Bidders were required to guarantee these limits would be met by the specified pressure filter system with Greensand Plus media. When there was pushback in guaranteeing the performance of the system (that the engineer had designed) without any prior testing to show this was achievable, the response from the engineer was that there were other Greensand Plus filters in the State that were achieving these levels so there should be no issues making the performance guarantee…

This was essentially saying that the performance of a treatment process on one water source should be expected on a totally different source water without considering the water quality of the two sources. Anyone who knows anything about water treatment knows while iron is relatively easy to remove, manganese is a totally different animal. While manganese may be easy to remove on one water source, it could be very difficult to remove on another.

 In Chapter 3 of the AWWA ‘Iron and Manganese Removal Handbook, Second Edition’ the following statements are made:

• Oxidation of Fe and Mn: Manganese Dioxide (manganese in the oxidized form) forms a far finer floc (than ferric hydroxide), so fine at times that a granular media filter will not remove it.
• Organic Complexing of Fe and Mn: Operators experiencing difficulty in removing Fe and Mn (especially Mn) have uncovered some common factors:

o   A level of organic carbon (TOC) over 2 mg/L

o   Some level of ammonia or hydrogen sulfide in the feed water

• Adsorption Removal Methods (my summary): Manganese is best removed by adsorption on a manganese dioxide media like Greensand Plus or Pyrolusite. Iron is best removed by precipitation/filtration because iron adsorption blinds the media. Therefore, when both are present, the best process used is a combination of iron oxidation/filtration and manganese adsorption.

Further to the last point, oxidation of manganese takes a much longer time than iron where you are looking at from seconds to a minute for iron (Chapter 5, Chlorination) and up to up to 30 minutes or longer for manganese. Therefore in a filter system where an oxidant is dosed in the feed piping to the filters you can have adequate time in the piping and space in the filters above the media for iron oxidation (a few minutes) while allowing adsorption removal of the manganese.

There was also a very good article in AWWA’s Opflow in December 2021 titled “Evaluate and Optimize Manganese Treatment”. This article explains that the form and levels of manganese can vary considerably between wells. All manganese removal methods described in this article are based on sorption to the filter media. Therefore conditions must be optimized for the sorption mechanism on manganese oxide coated media including ensuring there is a free oxidant residual to provide a continuously regenerated adsorptive surface. The pH also impacts the Mn reaction kinetics with pHs above 7.0 more favorable.

As mentioned above, TOC, ammonia and H2S create a chlorine demand which impacts the chlorine available to oxidize the Fe and regenerate the filter media for Mn adsorption. Because the iron oxidation reaction is a lot faster compared to TOC, you typically get iron oxidation in the presence of TOC, as long as the iron is not organically bound to the TOC. When ammonia and H2S are present you may need a higher chlorine dose to overcome the demand from these compounds and provide sufficient iron oxidation. While you are not trying to remove manganese by oxidation/filtration, you still need a free oxidant residual to keep the manganese dioxide media regenerated so that is adsorbs the manganese. Therefore, a water with a high chlorine demand can impact the ability of the media to adsorb manganese. If ammonia is present, potassium permanganate may be a good option rather than chlorine as the oxidant because it does not react with the ammonia.

If iron and/or manganese is complexed with organics, the oxidation process can be significantly impacted. At a minimum, a higher oxidation dose and longer oxidation time will be required and if this works you could still create another problem with the formation of disinfection byproducts. Coagulation may be a better option to remove organically bound manganese and possibly iron also.

So clearly, iron and particularly manganese removal chemistry is not simple, and you can’t assume if the Fe and Mn levels on one water source are similar to another water source that a particular treatment technology will work equally on both. Other constituents in the water source impact removal performance and must be taken into consideration and ideally bench and/or pilot testing should be conducted to confirm the effectiveness of a proposed treatment process. To steal a saying from an old Mobile oil commercial, Manganese Removal Ain’t Manganese Removal!

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

Has Ceramic Membranes Missed its Window of Opportunity?

 

Some ceramic membrane advocates may not like what I am saying here, but I believe the window of opportunity in the U.S. for ceramic membranes is closed… Ten to fifteen years ago when many of the polymeric membranes on the market had significant integrity issues, there was a lot of interest in ceramic membranes offering warranties of 20 years or more and virtually no breakages over this period. At that time the leading manufacturer of ceramic membranes for large municipal systems was Metawater (know as NGK up to 2008) with a large installed base in Japan. Originally Metawater had an exclusive arrangement in the US to sell through Kruger and a contract for a 5 MGD system was secured with Parker CO around 2009. At this time, Memcor and Zenon, two of the largest membrane system suppliers at the time, had experienced a lot of membrane integrity issues at many installations helping to create a lot of interest in ceramic membranes. Despite this interest, high costs of ceramic membranes and the systems prevented adoption for drinking water applications at any other large-scale installations (see my 2011 post). Around 2015, when Metawater had started selling their ceramic system directly rather than through Kruger, a 7 MGD system was installed at Butte MT. I wonder if selling through Kruger was not the best strategy, where Kruger was not well known as a membrane system supplier and had a large suit of established water treatment technologies (such as Actiflo) that would have diluted the sales and marketing effort towards its ceramic membrane systems. I think the opportunity was missed to sell a lot more ceramic membrane systems 15 years ago.

Membrane Integrity Advantage over Polymeric has diminished the Past 10 years

At the time that Memcor and Zenon were having their membrane integrity issues, Pall with the Asahi membrane was quickly establishing a reputation of having a very robust membrane with minimal fiber breakages and was quickly gaining market share. Riding on the back of Pall’s success, around 2010, companies such as Toray and Dow (now Dupont) brought membranes to market that had similar fiber thicknesses, same material (PVDF) and were outside-in pressurized modules as were Asahi’s. As OEMs such as Wigen Water Technologies and H2O Innovation installed systems with these membranes it was found that these membranes did have significantly improved integrity compared to the earlier Memcor and Zenon submerged membranes. I do have to mention that as the early pioneers of large-scale MF and UF membranes, Memcor and Zenon were learning on the run about membrane materials, module construction and cleaning regimes. The later entrants to the market have capitalized on these developments to produce very good membrane modules the past ten years.

With much improved polymeric membranes available now, plus the ability to have Open Platform/Universal MF/UF racks, I do believe the opportunity for wide adoption of ceramic membranes for standard municipal applications has passed. I discussed this with some ceramic membrane veterans (ex Metawater, PWNT and Nanostone) at AWWA's ACE in San Antonio last month and they said there are still good opportunities in Europe for replacing some of the older, poor performing UF membranes (I assume these are inside-out PES membranes), none of which really gained traction in the U.S., with the exception of the Inge/Dupont multibore membrane which is a lot stronger than its predecessors. But I have to say it looks like ceramic membranes will remain to a niche product in the U.S. in the foreseeable future as I predicted in my post back in 2011.

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

Equipment Supply Contracts Should be Thrown Out and Started Again

 It is time for OEMs and Contractors to make a stand!

Ever since I have been involved in the capital supply business in North America, equipment procurement contracts in the water treatment industry have treated suppliers as banks for contractors and owners, with ridiculously long price validation periods, crippling liquidated damages for delays and uncapped liabilities. Well maybe the times are finally a-changin’!

In times of low inflation, stable government, no pandemics, reliable supply chains, no conflicts in regions with critical raw materials and a competitive contractor bidding market, perhaps the contracts of the past presented less risk to OEMs. How long ago has it been since we were in that situation??

Contracts that require the OEM to hold a bid price for 90 days before award and then when awarded, hold the price for 1-year before delivery (and I have seen up to 3 years) can’t be accepted anymore. That is being a bank for the contractor and owner where the OEM is financing the project, having to pay material suppliers well in advance of shipping the equipment (where delivery is often the major payment milestone) and absorb any price increases from the original quote from a vendor (which could be provided weeks before the bid) through submittal preparation and approval and notice to commence manufacturing which is often at least 6 months and longer for major process equipment. And that was a concern before the current supply chain issues! Not to mention preselection or direct bids as is often used for membrane systems, where following submittal approval the owner then goes to bid to contractors to install the equipment – the lead time from original quotes to actually getting the notice to commence manufacturing is often a year or longer. Engineers and owners are in for a rude awakening to OEM responses to contract terms for preselection or direct bids in the future…

Here are a few examples of how current market conditions have brought OEMs to the tipping point of outright rejection of traditional contract terms:

Following the concern with nickel supply because of the Ukrainian war, suppliers of stainless steel are only holding quoted prices for 24 hours. How can you bid a project with stainless vessels and piping without significant risk of margin erosion or even losing money? After the pandemonium in the nickel market a well-known manufacturer of stainless steel cartridge filter housings voided all quotes given before March 4. So what about the bids you used their pricing for prior to that date? Is that a case of Force Majeure?

Allen Bradley components, the predominantly specified controls for water treatment systems, already had stretched lead times from 8 weeks to 24 weeks earlier this year. Then there was a Corona Virus outbreak in Shenzen, China’s silicone valley, where some AB components are made – now AB is not committing to any delivery schedule… How then can you sign a contract with LDs when you don’t know when you can get a critical component required to operate the system? And what about contracts you signed in 2020/21 before there were these delays – that is certainly Force Majeure! I feel that controls components have become the toilet paper of the water industry with end users and equipment manufacturers hoarding them where they can, increasing leads times further...

Some may say that OEMs should just build in contingency to prices when it is known how long the price is to be held for. So when we bid a project in January where the price is to be held for 90 days before award, how do we know there is to be a war between Ukraine and Russia that starts in late February resulting in nickel prices skyrocketing in early March and stainless steel prices doubling in days? And that is only 40 days after the bid? And then ten vendors are listed on the bid, some you have never heard of, and you have to hope all ten will have same concerns as you and object to the same contract terms or put in the same contingency…

Some may say why not order materials as soon as submittals are approved to reduce the risk of price increases. This is the bank situation again. Then the OEM must pay for these materials often well before they are delivered, creating a cash flow problem, and what if the project is delayed? Will the owner accept and store the equipment when built and pay for it? Most likely not, but that is an option that should be seriously considered. Contractors on the other hand keep time sheets for work conducted and are paid for labor and materials received on site on a monthly basis. OEMs are not paid a penny for factory labor used in building the equipment each month and rarely paid for materials received in the factory.

Contractors and sometimes engineers often respond to OEM exceptions to LDs and unreasonable liability limits saying they are passing down what they have in their prime contract with the owner. Well, contractors and engineers need to show some guts and take exception to the contracts being passed to them by owners. In these times, nobody can guarantee meeting a schedule. Owners have to face reality and think of a different way to ensure contractors make their best effort to meet schedule and budget.

Currently, OEMs and contractors have a unique opportunity to change the draconian contract terms they have begrudgingly accepted for decades to terms that are fairer for all parties involved. If contractors and OEMs unite and show some gumption in objecting to these traditional one-sided contracts, OEMs may not need to be financing projects anymore and with better cash flows on projects, prices may actually come down, where lower margins are more feasible. That would be a win-win-win for OEMs, contractors and owners!

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

Why Membrane Module Manufacturers should not use Independent Sales Reps

 

In recent years a few of the membrane module manufacturers have been using independent sales representatives which I believe is a bad idea and a case of biting the hand that feeds you. Typically, module manufacturers’ internal salespeople, and I am referring to MF/UF modules here, have directly sold to OEMs/System Integrators as well as marketing to end users and consulting engineers so that their products get specified. I am perfectly OK with that. What I am not OK with is the module manufacturers signing up independent sales reps to sell their products which opens up a can of conflicts. Let me clarify that I am talking about new MF/UF systems and not replacement modules at existing systems. I get that some new module suppliers on the market want to find opportunities ASAP and see independent reps as a way to get directly to engineers and end users rather than have to go through OEMs, but this is going to do more harm than good for the following reasons:

The module manufacturers don’t build the MF/UF systems and won’t be bidding the projects, so they still need OEMs to bid with their modules. The rep may also represent one of the OEMs bidding a project who may or may not want (or be able) to bid a system using that module and that likely will prevent competitor OEMs from bidding with that module. So now there is possible conflict created between the rep, his OEM and the module manufacturer as well as conflict between the module manufacturer and other OEMs. At best you may get the rep’s membrane system OEM bidding with the module, assuming that OEM isn’t a proprietary system supplier (Pall, Suez, Memcor/Dupont) and is willing to bid with the module. You also have to understand the dynamics between reps – the module rep will expect a commission for a sale whether his OEM or a competitor’s OEM wins the job as long as the module is selected. Competing reps that win the job don’t want to see commissions going to their competitor for the membranes and will therefore encourage another membrane to be used. This is a very messy arrangement (and difficult to explain) and is going to steer many reps and OEMs away from using the module.

I understand that the objective of using a rep who may be close to the specifying engineers, is to get the membrane listed in the specs and ideally flat spec’d so all OEMs have to use it. It is a very rare situation where you will get a module flat spec’d so in the case where it is listed with other modules, at best only the module manufacturer rep’s OEM will bid the job with that module. I had a project a few years ago where one such module was listed for a project and our sales rep represented that module as well as another OEM who was also listed for the project (not an ideal situation for an OEM but with all the mergers, etc in the industry you can end up with a rep having two competing OEMs). I called the module manufacturer for a quote and was told “sorry we are teaming with the other OEM on this one, but would love to work with you on another project”….. That is the last time we seriously considered that module and it wasn’t long before we also found a new rep in that region.

Before I get some module manufacturers too angry, I’m not talking about membrane replacements on existing systems where there is no role for the OEM. In that case it can make sense to have a rep involved to get the new replacement module qualified and help with the bidding process. But the reps should not be provided any incentive to push this module on new systems and risk opening the can of conflicts.

So how does a new module manufacturer get to market? Obviously, you have to sell to OEMs with the objective of having as many as possible bid a project to increase the chances of the module being selected by the winning bidder. In parallel you have to go direct to the engineers and end users to get a comfort level with the module and have it put in the specification. This latter point is very important. As an OEM, you have a lot of options (this applies to RO membranes also) and OEMs often don’t have time to market a new product to get it spec’d. There are exceptions when the OEM sees an advantage in bidding the new product, but in this crazy busy world right now, very few have time to pause and find the right opportunity do this up-front missionary work. So that is why some module manufacturers are using reps, right? I get it, and it may help on a specific project if all the stars align but in the long run to maximize sales opportunities it is better for module manufacturers to not use reps. Don’t bite the OEM hand that feeds you!

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

’21 Membrane Technology Conference Exceeds Expectations – The Wrap

With almost 600 attendees, around 200 more than expected, the 2021 Membrane Technology Conference (MTC) at West Palm Beach, July 19-23, was a resounding success! While this show normally has 900-1200 attendees, getting 60% of this number was a fantastic result for the first National water industry conference since the Covid cancellations (this show was cancelled the week before it was due to be held in early March 2020).

So why was MTC such a success?

For me, it was seeing the beaming faces of colleagues reuniting face to face after 18 months or more of working at home. The networking opportunities that can’t be replaced by Zoom calls. The large parties of conferences past were not held but the outdoor bar at Copper Blues became a popular hangout after dinners each night.

While the technical program had a few less sessions, the quality of the presentations I went to was excellent. One thing I noticed that was a lot different from other years was a lot livelier discussion after presentations – maybe people were bursting to be heard after being locked up for so long. Whatever the reason, it was great to hear these discussions.

There were less exhibitors this year, maybe 70% of other years, but the turnout was still strong and provided a great opportunity for delegates to catch up with manufacturers. Representatives from some manufacturers who didn’t exhibit were still present. Of course, there have been a lot of acquisitions since the last MTC in March 2019, so for instance, Dupont, Inge and Memcor shared a large booth for the first time.

 I think the timing also helped with a late surge of registrations. In late June/early July the country was very optimistic about vaccines slowing Covid and the Delta variant was in its early stages.

 What was new?

The hottest technology trend that I saw was a large number of presentations on novel high recovery RO processes that are now being adopted full-scale. We have heard of CCRO applications at past shows and also this one, but we are now hearing of Pulse Flow RO and Reverse Flow RO starting to be scaled up, so the folks at Dupont/Desalitech may have some competition in the near future. I still think these are niche technologies that are a fit in certain situations and not yet mainstream technologies, but I’m open to changing my mind as more data from different applications at full scale installations becomes available.

Congratulations to AMTA/AWWA for taking the risk with the first national in-person water conference since the Covid shut-downs and pulling off a great show! With this years MTC delayed 4 months due to Covid, it wont be long until MTC22 in Las Vegas, February 21-15. I can’t wait!

Increasing RO recovery is not just a case of adding stages!

I had an engineer recently tell me he was working on a project where they needed to minimize RO brine volume and he wanted at least 90% recovery, so please quote a 3-stage system… Antiscalant projections on the raw water quality showed 78% recovery at best, even with acid dosing. The chemistry won’t allow any higher recovery on this water on matter how many stages the RO system has, and don’t get me started on whether CCRO can do better (I’ll discuss this later).

That is the fourth inquiry like this I have had in the past 6 months and the second from this engineer who is finding it hard to understand the limitations on recovery… so I thought I would put the explanation in print here.

Before you start to think of how many stages you need to design the RO system for, you first need to look at the water chemistry to see what recovery is possible. All the antiscalant manufacturers have projection programs where the raw water quality data is entered, an antiscalant is selected and from the empirical data the program calculates the maximum recovery that can be achieved and what are the limiting salts. You can adjust the feed pH to see the impact of pH correction and you can also change some feed parameters so see how pretreatment will impact recovery. At this point, stages do not even come into the equation. For a customer that wants to get as high a recovery as possible, I also often ask the antiscalant suppliers to do a projection for me, because sometimes they have a product I may not be aware of or that is not part of the projection software version I have.

PLEASE NOTE - INCREASING THE NUMBER OF STAGES DOES NOT ALLOW A HIGHER RECOVERY THAN WHAT THE ANTISCALANT PROJECTIONS PREDICT!!! ALSO, INCREASING THE NUMBER OF STAGES DOES NOT ALLOW A HIGHER RECOVERY THAN WHAT THE ANTISCALANT PROJECTIONS PREDICT!!! Got the message??

Some antiscalant projection programs incorporate calculations on RO unit arrays, but I prefer to first optimize recovery then use the membrane manufacturer’s projection programs to design the best array – I just feel more confident with the RO/NF system design when I use the membrane vendor programs.

Now that I know the maximum recovery that is possible determined by the water chemistry, not the number of RO unit stages, I then go about working out how many stages are needed to achieve this recovery. When designing an array for an RO system there are several important design conditions that need to be accounted for, including crossflow velocity and flux across the membrane elements. The projection programs have built in warnings when these are too high or low. Operating outside the safe ranges will result in membrane fouling.

A 2-stage RO system is limited to up to 80-85% recovery because somewhere in this range you will violate the minimum crossflow requirements for the membranes. When the crossflow is too low you can get concentration polarization at the membrane surface resulting in scaling. By adding a third stage you can reduce the number of housings required in the first 2 stages to increase the crossflow velocity to within the desired range and add back those housings via the third stage to maintain the desired flux rate. For instance, rather than try achieving 85% recovery using a 4:2, 7M array at an average flux of 15 gfd at a permeate flow of 175 gpm which sends some low crossflow warnings for the first stage, you could change this array to a 3:2:1, 7M 3-stage system which has the same flux but the crossflows are better balanced across the membranes.

When attempting really high recoveries, where the water chemistry allows, you may even need to add a fourth stage. Another option to adding stages, is to recycle some Stage 2 concentrate back to the Stage 1 feed to increase cross flow velocity and allow higher recoveries but this increases the concentration of feed water constituents and subsequently the permeate quality is worse.

 And CCRO is not the silver bullet either!

Now a short discussion on ClosedCircuit RO (CCRO). The recovery rate of a CCRO system, like conventional RO, is limited by the chemistry and how much the feed water salts can be concentrated with antiscalant addition. In most cases, the recovery of CCRO is predicted by the antiscalant projections exactly the same as for conventional RO. Because CCRO purges the recycled concentrate every 15-45 minutes, if silica is the constituent limiting the recovery, due to the saturated silica concentration being reached towards the end of this cycle and the slower induction time for silica to precipitate once it reaches saturation (say 10 minutes), CCRO can push past the maximum recovery predicted by antiscalant projections. For that scenario, CCRO will achieve a higher recovery than a conventional RO system.

But for more common scalants such as calcium carbonate and calcium sulfate, the induction time is just seconds and the CCRO process offers no advantage over conventional RO if these are the limiting salts. I would be happy for someone to give me a good technical explanation how CCRO can achieve a higher recovery when CaCO3 and CaSO4 are the limiting salts because from my investigations I have not found one. Don't get me wrong, I'm all for new technologies that can improve on the recovery of conventional RO systems, but I also want to see good science on how this is achieved.

The main message I want you to get from this post though is the following:

INCREASING THE NUMBER OF STAGES DOES NOT ALLOW A HIGHER RECOVERY THAN WHAT THE ANTISCALANT PROJECTIONS PREDICT!!!

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