Set the flow, peaking factor and peak duration — get the basin volume that smooths the diurnal
surge, the hydraulic retention time, the surface area and the mixing power. The unit that turns a spiky
SEA influent into a steady feed for the biology and the dosing skids.
1Duty & basin
Size the basin to absorb the peak surge while discharging at the average: V = (Peak−1)·Q·τ/24. Then mix to stop septicity and keep solids in suspension.
Results — basin & mixing
EQ volume V
—m³
Retention
—h
Mixing power
—kW
Item
Value
Basis
2Mass balancing
What the basin actually does to the flow and load profile hitting the plant.
Item
Value
Basis
Operation envelope
Item
Value
Basis
Quote the EQ instruments at factory price
An equalization basin needs in/out flowmeters, a level transmitter, pH and the mixer/VFD signal —
all mappable to our catalogue and supplied at the manufacturer's ex-works price (margin from the export rebate only).
Mixing 4–10 W/m³ (mechanical) or 0.006–0.012 m³ air/m³·min (diffused); power = V·w_mix (mechanical) — prevents settling & septicity.
Full derivation and worked example: Equalization-Basin-Calculation-Sheet.md. The EQ basin is the buffer that makes every downstream unit predictable — run it, then carry Q into the primary clarifier.
