Sludge buildup in municipal and industrial wastewater lagoons is a growing and costly challenge. Across North America, operators are facing rising maintenance costs, shrinking lagoon capacity, non-compliance risks, and frequent dredging bills that can run into hundreds of thousands—even millions—of dollars. And yet, most lagoon systems are still relying on outdated or misapplied aeration technologies that exacerbate rather than alleviate the problem.

It’s time to look at sludge remediation through a different lens—one that focuses not just on oxygen transfer efficiency but on total lagoon mixing, dead zone elimination, and long-term cost avoidance. One that prioritizes maintainability, safety, and adaptability in all climates. A successful approach to sludge remediation depends not only on oxygen, but on how effectively the lagoon is mixed and maintained over time.

And that starts with choosing the right aeration system.

The Cost of Ignoring Sludge Buildup

Sludge is an inevitable byproduct of wastewater treatment, but not all sludge is created equal. Much of it, especially in early treatment stages, is composed of volatile solids, which can be biologically digested and reduced in volume under the right conditions. The rest is non-volatile and requires physical removal.

Too often, lagoons fill with volatile solids simply because the conditions needed for effective digestion aren’t being met. Sludge accumulates in stagnant zones, shrinking hydraulic capacity and disrupting the solid retention time (SRT) necessary for treatment. The result? Short-circuiting, permit violations, and emergency dredging, all of which point to a deeper problem: the sludge remediation process isn’t working as it should.

“I’m working on a project now where they spent $2 million dredging a lagoon—and they didn’t even get it all,” says Lewis Titus of Titus Wastewater Solutions. “That’s a huge cost that could have been mitigated with the right aeration and mixing system in place.”

Why Mixing Matters More Than You Think

Engineers traditionally evaluate aeration systems by looking at pounds of oxygen per horsepower per hour. But that’s only part of the story. For lagoon-based systems to perform effectively and support sludge remediation, mixing efficiency—how thoroughly the lagoon volume is circulated—must be a top consideration.

Most traditional systems (bottom diffusers, high speed surface aerators, brush-type surface aerators, aspirating aerators) are either stationary or fixed into limited positions, leaving large swaths of the lagoon unmixed. These dead zones are sludge traps, allowing solids to settle, accumulate, and eventually compromise the entire lagoon’s treatment capacity.

Choosing the Right System for Sludge Remediation

Not all lagoon aeration systems support effective sludge remediation. Here’s how common aeration options compare.

1. Bottom Diffuser Aeration Systems

• Pros: High oxygen transfer efficiency; effective for deep basins, function in cold climates.
  
• Cons: Fixed in place; prone to clogging, poor mixing; buried over time by sludge; expensive and risky to maintain, high installation costs.
  
• Not ideal for: Lagoons with high solids content.
  

2. High-Speed Surface Aerators / Brush Aerators

• Pros: Simpler installation; visible agitation, relatively good O2 transfer rates.
  
• Cons: Fixed position, and extensive restraint systems results in poor mixing; throws water into the air, which can freeze in cold climates and creates vapor and odor issues; maintenance intensive boat access maintenance generally required; power in water (safety issue)  limited lifespan in corrosive environments, prone to ragging issues.
  

3. Aspirating Aerators

• Pros: Will function in moderately cold climates; low initial costs, easy installation.
  
• Cons: Stationary thrust results in poor mixing; poor O2 transfer rate (can be improved with a shaft mounted blower, still only moderate.} vulnerable to ragging issues, and damage, power in water (safety issue), boat access maintenance generally required.
  

4. Floating Air-Driven Aerators (like the Titus FL)

• Pros: 360° discharge; no mechanical parts in the water (air driven); no boat access, maintenance; no power in the water, no dead zones; adapts to lagoon contours and depths; performs in all climates—even at -40°F, made from non corrosive Medium Density Polyethylene (MDF), no rotational torque or thrust. Can be easily moved around the lagoon or tank while in operation. ( Increases area of influence dramatically.) Will not rag up! Exceptional mixing efficiency. Excellent O2 transfer efficiency due to the fine bubble EPDM diffuser. (diffuser should last 10 years or more, can be easily replaced) Bottom or side intakes available. Simple installation, set in the water and tie off with a rope.
  
• Cons: Requires external blower, that may require sound attenuation ( located safely on shore); newer to market (but rapidly gaining traction with field success).
  

Why Floating Aerators Like the Titus FL Are a Game Changer

Floating, airlift-style aerators combine the best of bottom diffused and surface aeration without the drawbacks. The Titus FL Floating Aerator, for example, uses a membrane diffuser system inside an airlift pump body. As air is injected, it pulls and lifts water vertically before discharging it 360° just below the surface. This ensures full mixing, supports sludge remediation, keeps volatile solids suspended, and drives oxygen deep into the water column—all without any submerged motors, propellers, or parts that require in-lagoon maintenance.

“It’s a hybrid system,” Titus explains. “It acts like a bottom diffuser but floats—so it never gets buried in sludge. And since there’s no mechanical thrust, you don’t need anchors or cables. It just works.”

Performance and Safety Across Climates

Unlike surface splash-type aerators that throw water into the air (and create freezing hazards), the Titus FL aerator operates completely subsurface. This makes it ideal for northern and high-altitude installations where ice and extreme cold are a reality. In one project in Riverton, Wyoming, the system reliably ran at temperatures as low as -44°F and continued effective mixing beneath the ice, which helps maintain sludge remediation performance even in winter, while preventing the lagoon from freezing solid.

“The air going into the lagoon is elevated 50–60°F, so we’re actually helping warm the water slightly, not cool it,” says Titus.

Less Maintenance. Greater Safety. More Uptime.

Effective sludge remediation starts with equipment that’s easy to maintain and safe to operate. Floating, air-driven systems offer enormous operational advantages:

• All maintenance is onshore. No boats or confined space entries.
  
• No ragging. Membranes eject debris; no impellers to foul.
  
• No cable tethering. The unit can gently drift or be repositioned easily. Simply tie off with a rope.
  
• No electrical components in the water. Increases equipment life and operator safety.
  

A Paradigm Shift in Lagoon Treatment Strategy

For specifying engineers and municipal decision-makers, the key takeaway is this: Stop evaluating aeration systems solely on oxygen transfer specs in ideal conditions. Instead, ask:

• Does the system mix the entire lagoon?
  
• Can it adapt to increasing loads?
  
• How much maintenance will it require over 5–10 years?
  
• Will it function in extreme cold or heat?
  
• How does it affect long-term sludge management and cost?

When sludge remediation is successful, operators see measurable savings across the board.

“It’s not just about oxygen—it’s about effective delivery and mixing,” says Titus. “When you reduce sludge, you reduce costs. That means fewer dredges, lower energy use, better effluent quality, and happier neighbors.”

Coming Next in the Series

In Part 2 of this blog series, we’ll dive deeper into:

• Cold Climate Aeration Strategies
  
• Real-World Case Studies and Measurable Results
  
• Capital vs. Operational Cost Comparisons: Aeration vs. Dredging
  
• Odor Control and Regulatory Compliance
  

Want to learn more or schedule a demo?

Visit TitusWWS.com or call us to see how effective sludge remediation with floating aeration can extend the life and efficiency of your lagoon system—without the $400,000 dredging bill.