Bugs, Blowers, and Better Control: Inside Revere’s Approach to Smarter Wastewater Treatment
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An Interview with Leelon Scott, Senior Systems Specialist at Revere Control Systems.
In wastewater treatment, controlling how oxygen is delivered into the system can mean the difference between a clean, efficient process and a smelly, energy-draining mess. Behind the scenes, it’s microorganisms that do the real work: consuming waste, breaking it down, and transforming it into harmless byproducts. But to thrive, those “bugs” need just the right environment, especially when it comes to oxygen.
That’s where dissolved oxygen (DO) control comes in, and it’s an area where Revere Control Systems has spent decades refining their expertise. Working alongside OEM (original equipment manufacturer) partners across hundreds of installations, Revere has developed scalable, intelligent DO control strategies that balance biological needs with energy efficiency.
In this piece, Leelon Scott, a longtime specialist at Revere, talks through how it all works—from bubble size to blower oversizing to the systems that keep the bugs, and the process, balanced.
Q: For someone who doesn’t work in wastewater, can you walk through how the treatment process works and what role oxygen plays in it?
Leelon:
“A wastewater treatment plant is basically nature’s process, just organized and controlled. We use microorganisms (bugs) to break down the waste. Their job is to eat, reproduce, and die. When they die, they become sludge, and that sludge is separated out from the water.
The treatment process goes through four biological phases—oxic, anoxic, aerobic, and anaerobic—each with different oxygen conditions that support different types of bugs.
In one phase, for example, bugs need plenty of oxygen to break down organic material like food and human waste. In the anoxic phase, oxygen is limited, and different microorganisms step in to remove nutrients like nitrates from the water. Then there’s the anaerobic phase, where there’s no oxygen at all; this is often used to treat sludge and can even produce methane that some plants recover for energy.
Throughout the oxygenated parts of the process, we use blowers to push air into tanks through diffusers at the bottom. The bubbles carry oxygen into the water so the bugs can do their job. You’ll see both coarse bubble diffusers and fine bubble diffusers depending on the plant. Fine bubbles transfer oxygen more efficiently, but coarse bubbles are more durable—the choice depends on the process.
But, you’ve got to get the bubble size and air volume just right. Too little oxygen, the bugs die. Too much, and you’re wasting energy.”
Q: What is DO control, and how do you manage oxygen levels?
Leelon:
“We monitor the dissolved oxygen using probes in the tanks, and we use control valves and flow meters to regulate how much air each zone is getting. The blowers push air into a common header pipe, and from there, we use what we call “drop legs” to feed that air into different aeration basins or zones.
The system adjusts air flow in real time based on demand. It’s driven by instrumentation and SCADA systems, using established control logic that ensures smooth transitions across the plant. One of the strategies we use is called the “most open valve (MOV) theory.” It’s a way to distribute air efficiently by keeping the zone with the highest demand fully open, and adjusting all other valves relative to that. It helps the system avoid pressure imbalances and overcorrection.
Each blower has its own local control panel, which handles protection and flow control. The master panel monitors the total oxygen demand from all the basins and calculates how much airflow is needed in the system’s header. It can do this based on pressure, or by summing individual basin requirements. The master panel then decides how many blowers to run, at what capacity, and when to start or stop them. It’s all about balancing efficiency; adding blowers when needed and scaling back to avoid running too many at partial load.
It’s like conducting a symphony. The master control panel directs everything, and the local panels handle the individual blower settings.”
Q: Why is DO control such a critical part of wastewater treatment?
Leelon:
“Because it’s the biggest energy consumer in every plant. The blowers that push air into the system? They’re responsible for more electricity use than anything else. If you’re over-aerating, you’re blowing money.
With proper DO control, we can often cut that energy usage by 15 to as much as 30 percent, depending on the plant and how oversized the equipment is. Many of these systems are designed for future growth, so they’re oversized from day one.
That kind of energy efficiency isn’t just good for the utility’s budget—it’s good for the environment. You reduce emissions, extend equipment life, and improve sustainability.”
The aeration tanks are bustling with activity as powerful blowers pump oxygen into the water
Q: How did Revere become so specialized in this space?
Leelon:
“We’ve been doing this a long time. I’d say we’ve built and deployed around 200 DO control systems. We understand the process, blowers, diffusers, probes; it’s not just programming a panel.
We also stay until it works. There are companies that win the job, ship the gear, and disappear. We stick around during field deployment to make sure everything is calibrated, tested, and doing what it’s supposed to. That’s why I say “we’ve got competitors, but we don’t really have competition.”
Q: You mentioned that blowers are the biggest energy users in a wastewater plant. Can you talk more about how DO control helps with sustainability and cost savings?
Leelon:
“In most plants, blowers account for over 50% of energy use. Some use VFDs (variable frequency drives) to adjust blower speed, while others use inlet throttling—controlling the inlet airflow valve instead of the motor. Both methods can improve efficiency, and we’ve worked with both.
In multistage centrifugal blowers, throttling is common so you have to be more careful about protection. In positive displacement (PD) blowers, speed control is a factor. We’ve also worked with high-speed turbo blowers which use impellers spinning at 30,000 RPM.
DO control helps optimize any of these setups by giving the plant real-time feedback and automation.”
Q: These control systems often reach the end user as part of a larger packaged system delivered by an OEM. What role does Revere play in those kinds of partnerships and what makes those relationships work well?
Leelon:
“We’re often brought in during the early planning stages, when the OEM is putting together a turnkey system for the end user. We help define the specifications, size the system, and work through a questionnaire that covers blower count, number of zones, probe locations, and more.
We then deliver a budgetary proposal, followed by full engineering drawings and system documentation, all under their brand. It’s private-label work, and we’re completely embedded.
The end user sees one name on the panel, but we’re behind the scenes making sure it all works.”
Q: What’s next for DO control and wastewater automation?
Leelon:
“The big one right now is PFAS, those “forever chemicals.” The EPA just released new limits at the parts-per-trillion level, and plants are scrambling to comply. It’s going to take advanced treatment systems like granular activated carbon, ion exchange, and better aeration to keep up.
And all those new systems need more air, more blowers, more control. We expect a lot of growth in the next few years as utilities modernize their systems to meet these regulations.
DO control will always be foundational, but it’s now part of a much bigger picture that includes sustainability, resilience, and regulation.”
Did You Know?
🦆 If a duck were to land in an aeration basin, it might not float. These tanks are packed with millions of tiny bubbles from diffusers pumping air into the water. That constant aeration lowers the water’s density and disrupts surface tension. So instead of bobbing on the surface like normal, a duck could actually sink right into the water. It’s an unusual visual, but a great way to grasp just how intense the oxygenation process is in a well-aerated system.
🌱 Healthy wastewater treatment plants should smell like fresh dirt. A healthy wastewater plant gives off a fresh soil-like smell. If it smells bad, the biology’s off.
🔋 Blowers are energy hogs. They’re the number one power consumer in most plants. Smart control saves energy.
🌾 That potting soil? It might contain dried and treated sludge, called biosolids, from a wastewater plant. Once processed properly, it’s safe to use for things like landscaping or agriculture.
