2018 Membrane Technology Conference and CA WateReuse Conference Wraps

March was a busy month for conferences so I am combining my summary of the 2018 MTC in West Palm Beach and CA Annual WateReuse Conference in Monterey. There were may of the same West Coast engineers at both shows, which is an indication of the high use of membranes in wastewater recycling projects.

AMTA/AWWA Membrane Technology Conference

Attendance was similar to the past few years at just over 1000 delegates. It felt a little down to me based on exhibit hall traffic, but the quality of delegates was very good as usual, with a lot of interesting membrane projects in the works. The technical program was excellent, and I found myself torn between sessions many times when papers I wanted to see were being presented simultaneously.

There were quite a few sessions on potable reuse including studies directed at proving pathogen removal credits for MBRs and Reverse Osmosis for indirect and direct potable reuse of wastewater and the results look pretty conclusive with regulations to follow in the near future.

In terms on new technology, it looks like Metawater has some real competition now on the ceramic membrane front, with Nanostone recently completing some drinking water plant retrofits in the Dakotas. I think this a pretty good strategy for Nanostone where retrofitting will allow them to get some quick references for their ceramic membrane. The current target for the retrofits is cold water filtration applications where the capacity of systems with polymeric membranes is reduced in winter while the flux reduction for ceramic membranes is significantly less.

There were also a number of presentations on the use of Desalitech’s Closed Circuit Desalination (CCD) process for concentrating brine and improving recovery at wastewater reuse and brackish water applications. It looks like there will be some decent sized CCD systems in municipal applications on the West Cost in the near future.

WateReuse California Annual Conference

This was my first time at this show and I was very impressed with the number of delegates, around 600, which is about half of what is at the national WateReuse Symposium. A large percentage of those attending were water utilities, indicative of all the reuse activity in California. Since this was in Monterey, the Monterey One Water reuse demonstration plant and full-scale reuse system under construction were featured, including a tasting of beer made from the demonstration plant, a frequent and popular event at the WateReuse shows. I must say that Monterey One Water has done an excellent job with their demonstration plant that is set up for tours for all sectors of the community. I believe Pure Water San Diego probably had the first long term demonstration plant followed by Monterey and now many more water utilities are following suit to gain public acceptance of direct and indirect potable reuse.

Monterey One Water Demonstration Plant

I did hear in one presentation that the State of California is about to award pathogen log removal credits for MBRs and in anticipation of this, a number of future reuse projects are already removing UF from the Full Advanced Treatment (FAT) train and feeding RO directly from a MBR. Some of these full-scale projects are currently or about to bid. If you ask me, I am OK with MBRs as a barrier for indirect reuse, but I am not ready for MBRs without a subsequent UF filtration step as a pathogen barrier for direct potable reuse.

The organizers of this conference did a great job in planning every detail, including presentations and entertainment at lunches and breakfast (the WateReuse Family Feud was hilarious!) and I can see why the attendance at this show was so good.

Next major show, ACE18 in Vegas baby!

Has Adoption of Forward Osmosis Stalled?

Lack of Significant Progress the Past 6 Years



After seeing several papers presented at the WateReuse Symposium in Dallas in 2008, I was intrigued with the potential for forward osmosis in water and wastewater treatment with a lot of research completed on these applications and a lot of promising research underway (see 2010 post). I did wonder though if FO would be more of a niche technology due to process limitations such as the complexities of recovering water from saline and organic draw solutions. My prediction in 2010 that FO would be a niche technology appears to be spot on so far. While Oasys Water, one of the FO pioneers, has found some applications for produced water treatment in the O&G market, I am not aware of any adoption of FO in the municipal market.

 
I scanned the proceedings from the AWWA/AMTA Membrane Technology Conference the past several years to see if there were any trends in papers presented on FO – this conference has a good mix of research and full-scale case studies and I think is a good barometer of what is upcoming in the membrane industry and what is being commercialized. The reducing and flattening number of FO presentations suggests interest in this technology for mainstream water treatment is waning, perhaps due to some of the technological barriers preventing commercialization. Also, in contrast to the several presentations I saw at the 2008 WaterReuse Symposium, at the 2016 Symposium I did not see any FO papers on the proceedings.

I did a quick scan of the program for the upcoming 2017 AWWA/AMTA Membrane Technology Conference and found three platform papers and one poster on FO but for very niche applications and all presented by universities – so nothing to demonstrate that the technology is moving towards mainstream commercial implementation.


Forward Osmosis Papers & Posters at AWWA/AMTA Membrane Technology Conferences

 This trend in papers presented is in contrast to an article published in ‘World Water: Water Reuse & Desalination’s Autumn 2015 issue titled “Will forward osmosis always be a niche market” (O’Callaghan and Pearce). This article, based on a BlueTech Research Insight report, showed how there had been an uptick in the number of research papers published and patents registered from 2011 to 2013, suggesting increasing interest in building IP positions in the technology. A graph showing the number of published research papers from 2011 to 2014 did show a steady increase to 2013 but there was a slight drop to 2014 and I would not be surprised that this drop has continued to 2016 based on the US conferences I have looked at. The article does say that despite the research interest there are technical hurdles such as membrane fouling that have prevented the technology making any mainstream commercial impact and limited FO to some niche applications. It also makes a good point that the players in the FO market have been venture backed smaller companies, while the larger establish players in the membrane market have been watching from the sidelines.

The lower energy costs of FO compared to RO are certainly enticing although since 2008, significantly lower energy and oil costs may have reduced the attractiveness of this benefit, keeping the big players out of the FO market. One big change since 2008 is that the public is a lot more accepting of potable reuse following severe droughts in Texas and California. That could make the application of FO at combined seawater desalination/wastewater outfalls to reduce the energy costs of desalination, as described in my 2010 post, a lot more feasible. We will probably still need to see energy costs escalate again to get some serious interest from the larger players to invest in FO, sort out the technical issues and finally bring it to large scale commercialization. It will be interesting to see where FO is at in another six years!

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.