Blower map: pressure vs. airflow

Aerzen AT 150-0.8 S-G5 (4800 m³/h, 800 mbar max). Speed lines from dp = 1050·n² − 250·(Q/4800)² (map shape assumed), surge line through 2100 Nm³/h at 800 mbar (assumed), turndown 1900 Nm³/h. Grey: clean system curve (4.5 m submergence + diffuser DWP + grid and header losses). Dots: measured discharge pressure at the measured airflow.

Speed lines (60–100 %)Surge lineSystem curve (clean)Measured (trail)

Oxygen transfer: airflow needed vs. oxygen demand

Expected air = O2 demand / (0.2997 kg O2/Nm³ × SOTE(q) × αF 0.55 × driving force at the live DO and water temperature). SOTE 6.5 %/m at 4.5 m for Sanitaire Silver Series II discs (Xylem brochure). Band: ±15 %. Bars: specific aeration energy, measured vs. expected.

Expected (clean grid)±15 % bandMeasured (trail)

Aeration train

Inlet filter, turbo blower with VFD, air header with zone valve, diffuser grid in the aeration basin and the two DO probes, with live sensor values. Red = beyond the twin's alarm limit.

Condition sensors

Bars against the alarm limits in the twin file (red line).

Twin health: expected vs. actual

Measured vs. expected