Size aeration blowers using oxygen and volume. Adjust for efficiency, depth losses, and airflow units. Download results to share with crews and clients today.
| Scenario | Method | Key Inputs | Airflow (Nm³/h) | Pressure (kPa g) |
|---|---|---|---|---|
| Temporary site treatment tank | Oxygen-demand | 24 kg/day, 12% OTE, SF 1.10, depth 4 m | 800.0 | 45.2 |
| Equalization basin check | Volume-intensity | 250 m³, 0.60 Nm³/h·m³, SF 1.10, depth 4 m | 165.0 | 45.2 |
| Shallow aeration pit | Volume-intensity | 120 m³, 0.80 Nm³/h·m³, SF 1.10, depth 2 m | 105.6 | 25.6 |
Convert oxygen demand to an hourly basis, then divide by the oxygen delivered per unit air:
Multiply aerated volume by an aeration intensity, then apply a safety factor:
Discharge pressure is the sum of static head and system losses:
This power estimate uses standard flow for simplicity. Use vendor curves for final sizing.
Aeration sizing starts with a clear design basis. For wastewater tanks, oxygen demand can be developed from influent load, desired effluent quality, and process kinetics. On construction sites, temporary treatment often varies daily, so using a conservative demand plus a safety factor reduces under-aeration risk. The calculator accepts demand per day or per hour and converts it to an hourly requirement for consistent blower selection.
Overall transfer efficiency (OTE) combines standard oxygen transfer, field correction, diffuser condition, and mixing effects. Fine-bubble systems may deliver higher OTE than coarse-bubble, but fouling and depth changes can lower performance over time. Enter an OTE that reflects field expectations, not laboratory values. A practical approach is to start with vendor guidance, then apply a safety factor for aging and maintenance intervals.
Specifications and quotations may use different airflow units. This tool reports Nm³/h and also converts to m³/min and CFM for comparison with packaged blowers and portable compressors. Standardizing units reduces mistakes when matching blower curves, hose sizes, and manifold capacity. When equipment is rented, verify whether stated flow is free-air delivery or delivered flow at pressure.
Blower pressure must overcome hydrostatic head and system losses. Hydrostatic pressure is approximated as 9.81 kPa per meter of diffuser submergence. Add piping, valve, header, and diffuser losses to obtain a total discharge pressure. For early planning, a single loss value is adequate. For detailed design, losses should be recalculated for the chosen pipe diameters, fittings, and diffuser type.
Power is estimated from airflow, pressure, and efficiencies. Higher depth and losses increase discharge pressure and therefore kW. Efficiency inputs help translate shaft power to electrical demand for generator sizing and fuel planning. Use the result as a screening value; final power should come from manufacturer performance curves at the expected operating point, including turndown and control strategy. Track daily runtime to estimate monthly energy and cost.
It is airflow referenced to standard conditions, often 0°C and 1 atm. Using normal volume lets you compare blowers consistently. If a quote uses SCFM or ACFM, convert to the same reference before selecting equipment.
Use it when you know oxygen requirement from process data, loading, or treatment targets. It is best for sizing permanent systems or critical temporary plants where under-aeration could cause odor, low dissolved oxygen, or compliance issues.
Start with diffuser vendor guidance at your depth, then apply field corrections for wastewater, temperature, and fouling. If data is uncertain, pick a conservative value and increase the safety factor. Validate later with performance testing.
Aeration performance changes with diffuser aging, biofilm, varying loads, and maintenance delays. A safety factor protects against uncertainty and helps maintain stable dissolved oxygen. Typical planning ranges are 1.05 to 1.30, depending on risk.
It is a screening estimate based on airflow, discharge pressure, and entered efficiencies. Real power depends on blower type, curve shape, inlet filter losses, and control method. Confirm final kW using manufacturer curves at your operating point.
Select a blower that can deliver the required flow at the calculated discharge pressure with margin. Check the operating point on the vendor curve, then verify motor size, turndown range, noise limits, and standby capacity for reliability.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.