Coarse Bubble Diffusers
What Is a Coarse Bubble Diffuser?
A coarse bubble diffuser is a simple, robust aeration device that uses open orifices or slots to produce large bubbles (6–10 mm diameter). Unlike fine bubble diffusers that rely on perforated membranes, coarse bubble’s open design won’t clog in high-solids environments, has no membranes to replace, and creates vigorous circulation that keeps thick sludge in suspension.
Operators choose them where fine bubble diffusers — though more efficient for oxygen transfer — would plug up from sediment, carbonate buildup, or high solids content. With no moving parts and minimal maintenance, they’re the workhorse of dirty-water aeration.
Our Coarse Bubble Product Range
| Parameter | Cap Diffuser | Wide Band Diffuser |
|---|---|---|
| Design type | Dome cap with rim orifices | Tubular body with wide slot openings |
| Body material | ABS or SS304 | ABS or SS304 |
| Connection | ¾" or 1" BSP female thread | Side-entry or centre connection |
| Recommended air flow | 1.0–5.0 m³/h per cap | 5.0–20.0 m³/h per unit |
| SOTE (5 m depth) | 6–10% | 7–12% |
| Clog resistance | High — self-cleaning orifices | Very high — wide slots resist solids buildup |
| Corrosion resistance | Good (ABS) to Excellent (SS304) | Good (ABS) to Excellent (SS304) |
| Maintenance | Minimal — periodic visual check | Minimal — periodic cleaning of slots if needed |
| Best for | Anoxic zones, equalisation, grit chambers, post-aeration | Sludge digesters, large mixing zones, SBRs, high air demand |
Applications
Coarse bubble diffusers are the go-to choice wherever sediment, grease, or biomass buildup would quickly block the small openings on fine bubble membranes.
- Aerobic sludge digesters — thick sludge (2–5% TSS) needs vigorous mixing
- Equalisation / balancing tanks — prevents solids settling and septicity
- Grit chambers — abrasives would destroy fine bubble membranes
- Sludge holding tanks — keeps sludge mixed, prevents anaerobic conditions
- Anoxic / denitrification zones — gentle mixing without adding oxygen
- Stormwater storage tanks — reliable after weeks of inactivity
Why Choose Coarse Bubble?
Coarse bubble diffusers offer specific advantages that make them indispensable in certain applications.
Non-Clogging Reliability
Large orifices and wide slots resist blockages from solids, grease, and biological growth. In environments where fine bubble membranes would fail within weeks, coarse bubble keeps running.
Superior Mixing
Large, fast-rising bubbles create vigorous circulation that keeps thick sludge in suspension and prevents dead zones. No other aeration technology matches coarse bubble’s mixing power.
Low Maintenance
No membranes to replace. No small openings to clean. A visual check every 6–12 months is typically all that’s needed. Less downtime, lower labour cost.
Categories
Tell us about your project
Tank dimensions, target oxygen demand, wastewater type — and we’ll recommend the right diffuser size, membrane material, and layout.