Our lab partner today is Jed Harris, owner of Puretec Industrial Water with 
over 25 years of experience in the water industry, to delve into the world of Reverse Osmosis (RO) systems. Jed’s extensive experience and deep understanding of high-purity water solutions provided a wealth of knowledge, making this episode a must-listen for anyone looking to scale up their water treatment expertise. Below, we highlight some of the best insights Jed shared, aimed at making the complex world of RO systems more accessible and intriguing.
Reverse Osmosis: The Industry Workhorse
Jed describes reverse osmosis as the workhorse of water treatment, efficiently removing up to 99% of dissolved solids, organics, bacteria, and viruses. This process involves using a high-pressure pump to force water through a semi-permeable membrane, reversing natural osmotic pressure. Whether you’re in power generation, food and beverage, or pharmaceuticals, understanding RO systems is crucial as they play a pivotal role in ensuring water purity.
Common RO Applications and Challenges
RO systems are ubiquitous across various industries. Jed emphasizes their versatility but also highlights the complexities involved in managing them. He notes that the feedwater chemistry can vary, making it essential for operators to understand and monitor their systems to maintain optimal performance. This is particularly critical as the industry pushes for higher recovery rates, often pushing RO systems to their limits.
Key Metrics for Monitoring RO Systems
Trace Blackmore posed a crucial question; “What are some of the key things that we should be looking at to tell what’s going on within the RO?”. Jed Harris provided valuable insights; “You want to look at your flows, your qualities, your pressures, and last but not least, the feedwater temperature—which has a huge effect on all this stuff. You want to look at your permeate flow, your concentrate flow, your feed pressure, your concentrate pressure, and your permeate pressure if available. And then the qualities would be your feed conductivity and your permeate conductivity.”
Practical Tips for RO System Maintenance
Jed shared several practical tips for maintaining RO systems. He advises partnering with a company that can conduct water analysis and projection to set the system up correctly. Regularly collecting data—ideally daily—and using normalization software to interpret this data is crucial. He also cautioned against the impact of temperature changes, noting that a decrease in feedwater temperature can lead to a significant drop in permeate flow, potentially misleading operators to think there’s a problem when there isn’t.
Normalizing Data for Accurate Analysis
One of the most insightful parts of the discussion was on the importance of data normalization. Jed explained, “By normalizing the data, what you’re doing is essentially taking data when you start up the RO system, and then, as you go into the future, you’re comparing the current performance to how it should be at the baseline.” This helps accurately assess the system’s performance, especially when dealing with variables like temperature fluctuations that can significantly impact the RO system’s output.
Temperature’s Effect on RO
Jed Harris explains the critical impact of temperature on RO systems: “Temperature has such a huge effect on the amount of water that will go through a membrane. RO membranes are like the Miami Dolphins; they don’t do well in cold weather. The rule of thumb is for every one-degree Fahrenheit drop in water temperature, you’re going to lose about 1.5% in permeate flow. You might notice a decrease in permeate flow and think, ‘Hey, these membranes are dirty. They’re plugged. We need to clean; something’s wrong.’ But in reality, nothing’s wrong. It’s just that the feedwater temperature has dropped.”
Pre-Treatment is Key
Jed Harris emphasizes the crucial role of proper pretreatment for RO systems: “Pre-treatment is the key to everything.” Jed also highlights the growing adoption of Ultrafiltration (UF) systems, which offer a more consistent quality level compared to traditional multimedia filters. He outlines three primary objectives:
- Prevent Oxidizer Damage: Once an RO membrane is damaged by an oxidizer, the damage is irreversible.
- Inhibit Scale Growth: Delay and inhibit scale growth for as long as possible.
- Reduce Suspended Solids: Minimizing suspended solids helps achieve the highest possible recovery rate.
Biofouling: The Unavoidable Challenge
Trace and Jed addressed one of the most persistent issues with RO systems: biofouling. Jed explained, “Biofouling is a huge issue… it’s going to happen because we’re removing chlorine before the RO system.” As chlorine, an oxidizer, is removed to protect the RO membranes, any bacteria that enter the system will thrive due to the rich nutrient environment. Monitoring normalized data is crucial as it provides early signs of membrane fouling, indicating it’s time for cleaning. Jed highlighted a peculiar phenomenon: “When biofouling takes root in these membranes, a lot of times the normalized salt rejection will increase,” which can be misleading.
When and How to Clean Membranes
Cleaning membranes is both a straightforward and complex task. Jed Harris recommends against cleaning every time there is a 10% drop in normalized permeate flow, calling this practice excessive and potentially harmful to the membranes. Instead, operators should monitor the trends in normalized permeate flow and clean based on site-specific conditions. Typically, cleaning occurs every three months, but this can vary. Jed advises operators to watch for a drop in normalized permeate flow, an increase in normalized pressure differentials, and changes in normalized salt rejection as key indicators that cleaning is needed.
Cleaning Methods
There are two primary methods for cleaning RO membranes: on-site clean-in-place systems or off-site cleaning facilities. At Pure Tech, membranes are pre- and post-tested to assess their condition and effectiveness after cleaning. “Some membranes are just done… and others are returned to the customer and reinstalled,” Jed explained, highlighting the importance of thorough evaluation during the cleaning process.
Real-World RO Membrane Repurposing
Jed shared a humorous yet telling story from the pandemic. While visiting Egypt, he discovered that a village was using old RO membranes as the foundation for various structures. This anecdote underscores the importance of proper maintenance and the potential for repurposing equipment in creative ways.
Resources and Contact Information
For those interested in learning more, Jed recommended visiting Puretec’s website, where a wealth of resources is available. “Please visit our website puretecwater.com, and we have a great team here,” Jed said, inviting listeners to reach out for further assistance.
Conclusion
Jed’s insights into RO systems, from biofouling to membrane cleaning and real-world experiences, provide invaluable knowledge for maintaining and optimizing these critical systems. As always, we encourage our listeners to keep learning and implementing best practices to ensure the longevity and efficiency of their water treatment systems.
Learn More
For those who want to dive deeper, Jed has a comprehensive paper available on Puretec’s website HERE detailing how to collect and normalize data for RO systems. We highly recommend checking it out and implementing these best practices in your operations.
As always, we encourage you to keep learning and growing in your water treatment knowledge. Remember, as Trace’s father wisely said, “The day you stop learning in water treatment is the day you need to find a new career.”
Stay curious, stay informed, and keep Scaling UP your RO knowledge!
Your Scaling UP! H2O Team
Timestamps
01:00 – Trace Blackmore encourages you to reach out to someone you admire for help and to make a bucket list
07:00 – Upcoming Events for Water Treatment Professionals
09:00 – Interview with Jed Harris, owner of Puretec Industrial Water
47:00 – Drop by Drop With James McDonald
Quotes
“Biofouling is going to happen because we’re removing chlorine before the RO system, and any bacteria or living thing that makes it past into the RO system is just going to thrive. There’s a big food source in there, and they’re going to grow.” – Jed Harris
“If you clean at a 10% drop, you’re going to be cleaning nonstop, and if you clean too much, you’re going to affect the membrane’s ability to reject salts. You can’t just clean these membranes every day.” – Jed Harris
“Pre-treatment is the key to everything. When an RO membrane is damaged by an oxidizer, it’s done, it’s irreversible. Delay and inhibit scale growth as long as possible, and reduce the amount of suspended solids to up the recovery to its highest possible level.” – Jed Harris
Connect with Jed Harris
Phone: 805.340.6190
Email: jed@puretecwater.com
Website: puretecwater.com
LinkedIn: linkedin.com/in/jedharris/
linkedin.com/company/puretec-industrial-water/
Read or Download Jed Harris’ Press Release HERE
Links Mentioned
RO Data Collection and Normalization by Jed Harris
Puretec Water Resources
Ep 371 with Scott Slade
Ep 368 with Tim Fulton
Ep 35 with Wes Byrne
Ep 339 with Jane Kucera
The Rising Tide Mastermind
Scaling UP! H2O Academy video courses
Submit a Show Idea
Books Mentioned
The Wager: A Tale of Shipwreck, Mutiny and Murder by David Grann
Project Hail Mary by Andy Weir
101 So Bad, They’re Good Dad Jokes by Elias Hill
Reverse Osmosis: A Practical Guide For Users by Wes Byrne
Reverse Osmosis: Industrial Processes and Applications 2nd Edition by Jane Kucera
Drop By Drop with James
In today’s episode, I have a “what if.” What if the temperature of the makeup water feeding an RO decreases? How would a lower water temperature impact the RO’s performance? Will it impact the quality of the permeate water produced? Will it impact salt passage across the membrane? Will it impact operating pressures? Will it impact dechlorination chemistry, if used? Understanding the impact of temperature on water treatment systems can be important troubleshooting knowledge to have.
2024 Events for Water Professionals
Check out our Scaling UP! H2O Events Calendar where we’ve listed every event Water Treaters should be aware of by clicking HERE.
