How Metro Wastewater cut failures, costs, and downtime with Discflo
Imagine pushing sludge the consistency of peanut butter through a pipe, then loading that sludge with gas bubbles that shift, expand, and resist flow at every turn. That’s a challenge many wastewater plants face every day.
That was the daily struggle at Metro Wastewater Reclamation District, Colorado’s largest wastewater utility. Their anaerobic digesters produced a brutal mix of thick, hot, gas-entrained sludge with:
- Solids content of 2–4.5% by weight
- Viscosity of 1,300 to 5,000 SSU
- High temperatures from the digestion process
- Entrained air, making the flow unstable and unpredictable
When you ask a conventional pump to handle that kind of load, it fails.
Metro’s centrifugal and progressive cavity pumps stalled, clogged, and repeatedly broke down. Despite constant repairs and workarounds, the district remained stuck in a costly cycle of downtime and maintenance.
It was time for a different approach.
Why Entrained Air and Viscosity Break Conventional Pumps
Entrained air and high viscosity are two leading causes of pump failure in wastewater treatment. This is because they disrupt the basic hydraulic principles most pumps rely on.
Entrained Air: Small Bubbles, Big Problems
Centrifugal and PC pumps are designed for steady, incompressible fluids. However, air-entrained sludge behaves more like a gas/liquid hybrid, creating erratic pressure zones and unpredictable behavior.
Typical failure points:
Air binding and prime loss — Air gathers at the suction inlet, stalling flow.
Cavitation damage — Vapor bubbles collapse in low-pressure zones, damaging impellers and casings.
Pressure instability — Shifting air content causes vibration, shaft deflection, and long-term fatigue.
- Seal failure from dry-run conditions — When air displaces liquid, seals overheat and wear out.
High Viscosity: Too Thick to Flow
Thick, slow-moving sludge puts intense strain on pump systems. Most conventional designs simply aren’t built for the resistance it creates.
Common Failure Points:
- Insufficient torque — Standard impellers can’t generate enough force to push dense sludge. Flow slows to a trickle—or stops altogether.
Clogging and blockages — Viscous sludge with solids or stringy content easily clogs impellers, valves, and close clearances.
Overheating and power strain — Pumping thick fluid takes more energy and burns out systems.
Seal and bearing wear — Uneven pressure and high resistance increase mechanical stress, accelerating wear and failure.
Even in well-maintained systems, conventional pumps aren’t built for these conditions. The problem isn’t just the fluid; it’s a design mismatch.
How Discflo Solves the Entrained Air and Viscosity Problem
Conventional pumps fight thick, gassy fluids. Discflo takes a different approach.
Discflo’s patented Discpac technology eliminates impellers and tight tolerances entirely. Instead, it uses viscous drag and boundary-layer flow to pull fluid gently through the pump in smooth, laminar streams.
Entrained Air Performance
No cavitation: Laminar, non-impinging flow lets vapor bubbles pass through intact.
Stable flow with up to 80 percent entrained air: Even extreme gas content doesn’t disrupt operation.
No air-lock traps: Wide internal passages prevent vapor pockets from forming.
Always primed: Unlike PC or centrifugal pumps, Discflo doesn’t lose suction.
Viscosity Performance
Rated up to 100,000 cPs: Easily handles sludges, greases, and polymers.
Low to no close tolerances: Solids and stringy materials pass through without clogging.
Low-speed, high-torque operation: Reduces energy draw and wear.
Preserves floc integrity: Non-shearing flow protects delicate materials.
Minimal radial load: Low stress on seals and bearings extends lifespan.
Side-by-Side Comparison
| Category | Discflo Pumps | Conventional Pumps |
| Flow Design | Non-contact, laminar flow | Impellers/rotors disrupt flow |
| Entrained Air Handling | Up to 80% air, no stalling | Frequent air binding and cavitation |
| Viscosity Performance | Rated to 100,000 cPs | Efficiency drops above 350 cPs |
| Clogging & Blockages | Open path resists clogging | Tight clearances prone to jams |
| Seal & Bearing Wear | Low-stress flow extends life | Irregular loads cause failures |
| Maintenance Needs | Minimal maintenance | Frequent part replacement |
Metro’s Results: From Emergency Fix to Facility-Wide Standard
The results were impossible to ignore:
- Zero unplanned downtime
- No operational issues or failures
- Up to 90 percent reduction in repair, downtime, and maintenance costs
Impressed by the performance, the district adopted Discflo as a go-to solution. Today, twenty-eight Discflo pumps operate across the facility, handling a wide range of challenging services with minimal maintenance and maximum uptime.
Impressed by the performance, the district adopted Discflo as a go-to solution. Today, twenty-eight Discflo pumps operate across the facility, handling a wide range of challenging services with minimal maintenance and maximum uptime.
Is It Time to Raise Your Expectations?
Metro Wastewater faced the same problems as many treatment plants: unpredictable, gassy sludge that stalled their pumps and drained their resources.
Switching to Discflo solved the problem—and raised the bar. What began with four pumps quickly grew to twenty-eight, as performance and uptime proved consistent across the facility.
If entrained air, viscosity, or downtime are holding your system back, it might be time to raise your expectations, too.
👉 Talk to our team and see if Discflo is the upgrade your process has been missing.