COVER SERIES | Wastewater
Real-Time Analyzers in Wastewater Treatment
Brittany Baker speaks on reducing aeration energy costs and the future of wastewater monitoring.
Thom Baer | Pumps & Systems
Earlier this year on the Pumps & Systems podcast, we spoke with Brittany Baker, global product manager at ABB, about the role of real-time analyzers in wastewater treatment. To watch the full interview, visit the Pumps & Systems YouTube channel at youtube.com/@pumpsandsystemsmag.
Let’s start with the basics. What are real-time analyzers? What do they do and how do they integrate with pumps?
BAKER: “Real-time analyzer” is sort of a blanket term. There are different types of analyzers, [and] there are different types of technologies that you can use to monitor a particular water quality parameter. One that I think most folks are probably most familiar with is pH, because pH is very important and it’s probably the most widely used sensor on the market. There are other, different ones that are more advanced, but pH is probably the most common one that we see integrated with pumps in different systems. You can have submersible sensors; you can have bypass sensors, which means you have to physically bring a water sample to the analyzer. There are also different technologies and principles of operation.
Submersible sensors can use electrodes; they can also use optical light. They can also be color metric. If anybody has a pool, they’ve probably used a litmus test where you dip a pH strip in your water. Same idea. But these are devices that are going to continuously measure, so they can be as quick as milliseconds, depending on your process, or they can be batch or timed for every 10 to 20 minutes. And this is important, because if you’re doing real-time analysis and you’re doing process control, you want pretty quick results so you adjust your process as needed.
How do real-time analyzers help with reducing aeration energy costs, and what can you tell us about that process?
BAKER: I think it’s first important to understand: What is aeration? Aeration is primarily in wastewater applications, municipal wastewater. And what we do is we add air—very fine microbubbles—to the water, to our wastewater, to help digest pollutants. We want to get rid of all the nasty stuff that’s in the water, so we inject it with air, and microbiomes will actually use that air as energy to consume all the nitrates or other things that are in the water—so, other organics.
Now, aeration basins can be very expensive to run. If you can imagine, if you have a swimming pool, and you were constantly pumping air into that pool to make sure the water was staying healthy, that’s a very expensive endeavor. So, we use dissolved oxygen sensors. And those dissolved oxygen sensors will look at the oxygen concentration in the aeration basin based on this process, or [the] stages that it is in within that process. So, we inject the air, we look at dissolved oxygen and we adjust the blowers based on our dissolved oxygen content and where we are in the stage processes. There are different processes—different biomes like to use oxygen. They’re aerobic. Or we can go into anaerobic or anoxic zones where there is no oxygen present. They all serve a very unique and very different purpose for getting rid of your pollutants.
Aeration basins can account for anywhere from 60%-70% of the energy cost of the entire wastewater plant, so if you can reduce those costs by even 5%, 10%, 15% just by using automation using sensors, you can save yourself quite a bit of money.
Where do you see wastewater monitoring heading in the next 5 years or so?
BAKER: I think there will always be a place for reagent technology, and that’s because reagent-based analyzers will provide you with that repeatability and that accuracy and also measuring down to a very, very small range. Online analyzers that are not using reagents, they don’t have that ability yet. So maybe in the future, we will get there, but right now, that is a very, very hard benchmark to reach with optical sensors, but I think in the future, it will improve.
Thom Baer is a managing editor for Pumps & Systems and host of the award-winning Pumps & Systems Podcast. Visit pumpsandsystems.com.
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