Coarse Bubble Tube Diffuser
A Coarse Bubble Diffuser (CBD) is an aeration device used in wastewater treatment plants where mixing is more important than high oxygen transfer efficiency. It generates large air bubbles (typically 6–13 mm diameter) that rise rapidly, creating strong turbulence and mixing.
Typical Technical Specifications
Parameter | Typical Specification |
Bubble Size | 6–13 mm |
Diffuser Type | Disc, Tube, Dome, Pipe |
Membrane Material | EPDM / Silicone |
Body Material | PP, ABS, PVC or SS304 |
Air Flow Rate | 1–8 Nm³/hr per diffuser (depending on model) |
Operating Pressure | 0.15–0.60 kg/cm² |
Maximum Air Flow | Up to 10 Nm³/hr |
Head Loss | 50–150 mmWC |
Oxygen Transfer Efficiency (OTE) | 2–5% per meter water depth |
Operating Temperature | 5–80°C (EPDM) |
Connection | ¾”, 1″ BSP or NPT Thread |
Mounting | Screw Mounted / Saddle Mounted |
Standard Sizes
Type | Size |
Disc Diffuser | 90 mm, 150 mm, 215 mm |
Tube Diffuser | 500 mm, 750 mm, 1000 mm |
Dome Diffuser | 75–150 mm Diameter |
Comparison: Coarse vs Fine Bubble Diffuser
Parameter | Coarse Bubble | Fine Bubble |
Bubble Size | 6–13 mm | 1–3 mm |
Oxygen Transfer | Moderate | High |
Mixing | Excellent | Moderate |
Clogging | Very Low | Higher |
Best Application | Equalization, Sludge Tanks | Aeration Tanks (MBBR, ASP, SBR) |
Maintenance | Low | Medium |
Energy Efficiency | Lower | Higher |
Materials of Construction (MOC)
- Membrane: EPDM, Silicone
- Support Plate: PP / ABS
- Fasteners: SS304
- Air Connection: PVC / PP / SS304
Advantages
- Excellent mixing performance
- Low risk of clogging
- Suitable for high suspended solids
- Easy maintenance
- Long membrane life
- Operates with lower maintenance than fine bubble diffusers
Performs well in sludge and viscous wastewater applications.
Applications
- Equalization Tanks
- Grit Chambers
- Aerobic Digesters
- Sludge Holding Tanks
- Chlorine Contact Tanks
- Chemical Mixing Tanks
- Industrial ETP & STP
- Mixing of High TSS Wastewater
Comparison: Coarse vs Fine Bubble Diffuser
Parameter | Coarse Bubble | Fine Bubble |
Bubble Size | 6–13 mm | 1–3 mm |
Oxygen Transfer | Moderate | High |
Mixing | Excellent | Moderate |
Clogging | Very Low | Higher |
Best Application | Equalization, Sludge Tanks | Aeration Tanks (MBBR, ASP, SBR) |
Maintenance | Low | Medium |
Energy Efficiency | Lower | Higher |
Typical Installation Depth
- Minimum: 2.5 m
- Recommended: 3–6 m
- Maximum: 8 m
Typical Air Requirement
- 1–5 Nm³/hr per diffuser for standard operation
- Blower pressure generally 0.3–0.6 kg/cm², depending on water depth and piping losses.