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Activated Sludge Design

Treat the load, not the brochure.

Activated sludge, aeration demand, organic loading and pump-station sizing. Built for the wastewater engineers who keep it compliant.

A worked example

Conventional activated sludge

F/M 0.30 · MLSS 3000 mg/L

These figures come from the Tenselo engine. Every result Tenselo produces shows the inputs it used and the method behind it, so the work can be checked rather than taken on trust.

Inputs
BOD load 250 kg/d
Process Conventional
F/M ratio 0.30 /d
MLSS 3,000 mg/L
Results
278 m³
Aeration basin
6.7 h
HRT
7.1 d
Sludge age (SRT)
235 kg/d
BOD removed
0.30 /d
F/M ratio
3,000 mg/L
MLSS

Why it matters on the job

Basin sized to the load

Aeration volume, HRT and SRT worked from the BOD load and the process you've chosen.

Aeration that's enough

Oxygen demand and blower duty matched so the bugs keep working.

Clarifiers & pumps too

Sedimentation, RAS and pump-station sizing in the same pack.

What is in this category

10 Wastewater & Sewage calculators

Every calculator in this category, by its reference code. Running them needs a Tenselo subscription — subscriptions open soon.

  • WWS-001 Gravity Sewer Grade & Self-Cleansing

    Part-full Manning flow, velocity, depth & self-cleansing grade for gravity sewers (WSA 02)

  • WWS-002 Pump-Station Emergency Storage

    Power/pump-failure storage before overflow: required volume for a response time, or time-to-overflow for a given storage

  • WWS-003 Rising Main Sizing & Scour Velocity

    Pumped sewage main: velocity vs self-cleansing/scour, retention & friction (WSA 04)

  • WWS-004 Wet-Well Pump Station Sizing

    Active storage volume & well size, plus a single / duty+standby / duty+duty DAB FX pump pick (WSA 04 / Metcalf & Eddy)

  • WWS-005 Activated Sludge Design

    Aeration volume, F/M, SRT, RAS, sludge & oxygen demand

  • WWS-006 Clarifier / Sedimentation Sizing

    SOR area, diameter, weir & solids loading

  • WWS-007 Population Equivalent & Load

    EP, hydraulic & pollutant loads (BOD/COD/TSS/TKN/TP)

  • WWS-008 Grease Arrestor Sizing

    Commercial kitchen grease trap (AS/NZS 3500.2): 1-hour retention by peak flow or fixture units, to a standard size

  • WWS-009 Septic Tank & Land Application

    AS/NZS 1547 design flow, tank size & disposal area

  • WWS-010 Trade-Waste pH Neutralisation Tank

    Retention-tank volume and reagent direction to bring trade waste into the acceptance pH band

Subscriptions open soon

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