Aeration Blower Design Calculator

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Step 1: Process Design Parameters

Flow & Loads

Input Method

Flow Units

Average Day Flow (ADF) m³/day Average daily flow rate for aeration design

Converted to Standard Units:

ADF: 1000 m³/day

Influent BOD₅ mg/L Default: 250 (municipal sewage 200–300). Note: COD ≈ 2 × BOD. If COD only, divide by 2.

Influent TKN/NH₄-N mg/L Default: 40 (domestic 30–50)

Carbon O₂ Factor kg O₂/kg BOD removed Default: 0.6 (range 0.5–0.7)

Safety Factor for O₂ Demand Default: 1.1 (accounts for load variations, VFD handles the rest)

Effluent BOD Target

BOD Removal Required %

MSIG Standard A: 92% removal required (250 → 20 mg/L)

Nitrification Required?

Yes, include nitrification

Effluent NH₄-N Target mg/L

Denitrification Level

None

Partial (50%)

Full (80%)

Click "Calculate Process Requirements" to see biological design

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Step 2: Oxygen Demand Calculation

Environmental Conditions

Mixed Liquor Temp °C

Altitude m

Ambient Air Temperature °C

DO Setpoint mg/L

α Factor Field vs clean water transfer efficiency

β Factor Saturation concentration ratio

Diffuser Configuration

Diffuser Type

Submergence Depth m

OTE (Oxygen Transfer Efficiency) % Default: Fine pore ≈ 2.5%, Coarse bubble ≈ 1.2%

Max Air per Diffuser m³/h Fine: 2-6 m³/h, Coarse: 15-45 m³/h

Tank Area m² Aeration tank area (L × W)

Click "Calculate Air Requirements" to see oxygen transfer analysis

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Step 3: Blower System Design

System Pressure Requirements

Submergence Pressure kPa Calculated from diffuser depth

Diffuser Clean ΔP kPa Fine: 7-15 kPa, Coarse: 3-8 kPa

Fouling Allowance kPa

Piping ΔP kPa

Filter/Silencer ΔP kPa

Safety Margin %

Blower Configuration

Target Turndown Ratio

Redundancy (N+1)

Include standby blower

Blower Type Preference

Click "Design Blower System" to see blower specifications

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Step 4: Final Blower Selection Summary

Complete previous steps to see final recommendations