Resources

Tools & Calculators

Plug in your own plant numbers to get an accurate result for the calculations operators run every shift.

Chemical Dosing

Chemical Feed Dosage

Find the pounds per day of a chemical needed for a given dose concentration and flow.

Dose Concentration (mg/L)

Flow (MGD)

Enter all values above to calculate.

Full page with formula & worked example

Liquid Chemical Feed Rate

Convert a required dose in lbs/day into a metering pump feed rate for a liquid chemical.

Chemical Dose (lbs/day)

Specific Gravity

Percent Strength (%)

Enter all values above to calculate.

Full page with formula & worked example

Hydraulics & Flow

Detention Time

Calculate how long liquid theoretically stays in a tank or basin at a given flow rate.

Tank Volume (gal)

Flow Rate (MGD)

Enter all values above to calculate.

Full page with formula & worked example

Flow Unit Converter

Convert a flow rate in MGD to gallons per minute and cubic feet per second.

Flow (MGD)

Enter all values above to calculate.

Full page with formula & worked example

Disinfection

Chlorine CT Value

Calculate CT (concentration × time) for disinfection and check it against a required CT.

Residual Chlorine (mg/L)

Contact Time (T10) (min)

Required CT (mg/L·min) · optional

Enter all values above to calculate.

Full page with formula & worked example

Pumping

Pump Water & Brake Horsepower

Find the theoretical water horsepower and brake horsepower required for a pumping duty point.

Flow (gpm)

Total Dynamic Head (ft)

Pump Efficiency (%) · optional

Enter all values above to calculate.

Full page with formula & worked example

Activated Sludge Process Control

F/M Ratio

Compare the organic load entering the aeration basin to the biomass available to treat it.

Influent BOD (mg/L)

Flow (MGD)

MLSS (mg/L)

Aeration Volume (MG)

Enter all values above to calculate.

Full page with formula & worked example

MCRT (Sludge Age)

Calculate mean cell residence time from MLSS, wasting, and effluent solids data.

MLSS (mg/L)

Aeration Volume (MG)

WAS TSS (mg/L)

WAS Flow (MGD)

Effluent TSS (mg/L)

Effluent Flow (MGD)

Enter all values above to calculate.

Full page with formula & worked example

Required RAS Rate

Estimate the return activated sludge rate needed to maintain a target MLSS.

MLSS (mg/L)

RAS Concentration (mg/L)

Enter all values above to calculate.

Full page with formula & worked example

Clarifier & Solids

Surface Overflow Rate (SOR)

Check clarifier settling performance by dividing flow by surface area.

Flow (MGD)

Clarifier Surface Area (sq ft)

Enter all values above to calculate.

Full page with formula & worked example

Weir Overflow Rate

Check the flow rate per foot of weir length in a clarifier.

Flow (MGD)

Weir Length (ft)

Enter all values above to calculate.

Full page with formula & worked example

Solids Loading Rate

Check how many pounds of solids per day are applied per square foot of clarifier area.

MLSS (mg/L)

Flow (MGD)

Clarifier Surface Area (sq ft)

Enter all values above to calculate.

Full page with formula & worked example

BOD/TSS Removal Efficiency

Calculate the percent reduction between an influent and effluent concentration.

Influent Concentration (mg/L)

Effluent Concentration (mg/L)

Enter all values above to calculate.

Full page with formula & worked example

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