Design Manual › Pre-treatment › Aerated grit
FREE ENGINEERING TOOL · PRE-TREATMENT

Aerated Grit Chamber

Set the flow, detention, channel geometry and air rate — get the chamber volume, channel length, diffused-air demand and blower capacity, and the daily grit production. Air — not just velocity — drives organics away from the grit in this tropical headworks workhorse.

1Duty & chamber

Rectangular channels with diffused air along one wall create a roll that keeps organics in suspension while 0.2 mm sand settles. Size by peak-flow detention (1–3 min) and air rate (0.3–0.6 m³ air/m³ water).

Results — chamber & air

Chamber volume V
—m³
Channel length L
—m
Grit / day
—kg/d
ItemValueBasis

2Air & blower

Diffused air demand and the blower duty it implies — the instrument that actually runs this unit.
ItemValueBasis

Operation envelope

ItemValueBasis

Quote the grit instruments at factory price

An aerated chamber needs an inlet magnetic flowmeter, a level transmitter, a blower and its air-flow signal — all mappable to our catalogue and supplied at the manufacturer's ex-works price (margin from the export rebate only).

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Sources & parameter basis

[1]METCALF & EDDY 5th ed. / WEF MOP-8 — aerated grit detention 1–3 min, air 0.3–0.6 m³ air per m³ water, channel depth 2.5–4.5 m, design grain 0.2 mm, grit 5–10 L per 1000 m³.
[2]Volume V = Qp·t; cross-section n·b·H; length L = V/(n·b·H); horizontal velocity = Qp/(n·b·H).
[3]Air demand = AirRate·Qp; blower capacity = AirRate·Qp·60 (standard m³/min). Grit bulk density ≈ 1600 kg/m³ (wet).
Full derivation and worked example: Aerated-Grit-Calculation-Sheet.md. The aerated chamber is the organics-friendly alternative to the vortex — run it, then carry Q into the primary clarifier.
How do I size an aerated grit chamber?

Chamber volume comes from peak-flow detention time; channel length and the diffused-air rate keep 0.2 mm sand moving to the bottom while organics stay suspended. The calculator returns chamber volume, channel length, and the diffused-air requirement.

What blower capacity does an aerated grit chamber need?

The diffused-air system needs a blower sized for the air requirement at peak flow, plus margin. The calculator outputs blower capacity and the daily grit production for tropical municipal WWTP headworks.

Why capture grit before biological treatment?

Grit abrades pumps, fills pipes, and buries aeration diffusers if it reaches the tanks. Removing it at the headworks protects downstream equipment; the calculator sizes the grit removal up front.

© 2026 Nanjing JiuYuHui Environmental Technology Co., Ltd. · jiuyuhub.com · Municipal WWTP design manual — Pre-treatment (variant).
⚠ Screening values only. Outputs from this tool are engineering screening estimates. Final equipment sizing, and any construction or permit submission, must be confirmed against the manufacturer’s verified performance curves and the applicable local regulation (e.g., Vietnam QCVN 14 / Indonesia PERMENLHK 68).
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