Conventional Activated Sludge (CAS)
1Duty & reactor
Results — reactor & oxygen
| Item | Value | Basis |
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2Return & sludge
| Item | Value | Basis |
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Operation envelope
| Item | Value | Basis |
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Quote the CAS instruments at factory price
A CAS basin is instrument-dense: DO per zone, MLSS, RAS flowmeter, blower airflow and ammonia — all mappable to our catalogue and supplied at the manufacturer's ex-works price (margin from the export rebate only).
Request a quote for this duty ← Primary Clarifier Secondary Clarifier →Sources & parameter basis
| [1] | METCALF & EDDY / EPA — CAS F/M 0.2–0.5 kg BOD/kg MLSS·d, MLSS 2–4 g/L, SRT 3–15 d (carbon) to 10–25 d (with nitrification), RAS 0.5–1.5×. |
| [2] | Oxygen: carbon 0.9, nitrification 4.57, biomass 1.42 kg O₂/kg VSS (VSS≈0.3·BOD removed); blower SAE 1.8–2.5 kg O₂/kWh. |
How do I size an aeration tank for activated sludge?
Aeration-tank volume comes from the F/M ratio and the MLSS you want to hold, and the calculator returns the volume together with the resulting F/M so you can check it lands in the operating range.
What sludge age does a conventional activated sludge plant need?
Sludge age is reported alongside the volume so the retention can be checked against what nitrification requires, rather than being an implied consequence of the tank size.
How much return sludge flow is required?
Return sludge flow is calculated from the sludge mass that has to be held in the aeration tank, so RAS and the tank volume stay consistent with each other.
How is oxygen demand determined?
Oxygen demand is calculated for the organic and nitrogen loads you enter, giving the aeration requirement for tropical municipal biological treatment.