Operator math, worked
Class D operator math, solved step by step
The math on the Texas Class D exam, worked the simplest way, with a real example every time and a calculator to try your own numbers. These are the exact problem types you will see, nothing higher-grade.
- How to calculate the volume of a rectangular tank in gallonsgallons = length x width x depth x 7.48
- How to calculate the volume of a round tank in gallonsgallons = 0.785 x diameter x diameter x depth x 7.48
- How to calculate chlorine dose, demand, and residualdose = demand + residual (all in mg/L)
- How to calculate pounds per day of a chemicalpounds per day = flow (MGD) x dose (mg/L) x 8.34
- How to calculate detention timedetention time = tank volume / flow rate
- How to convert flow: GPM, GPD, and MGDGPD = GPM x 1,440 and MGD = GPD / 1,000,000
- How to calculate the area of a circle (the 0.785 method)area (sq ft) = 0.785 x diameter x diameter
- How to convert cubic feet to gallons (and back)gallons = cubic feet x 7.48 (and cubic feet = gallons / 7.48)
- How to calculate pounds of chlorine to disinfect a pipepounds = pipe volume (MG) x dose (mg/L) x 8.34
- How to calculate hydraulic loading ratehydraulic loading = flow (gpd) / surface area (sq ft)
- How to calculate the volume of a pipe in gallonsgallons = 0.785 x diameter_ft x diameter_ft x length_ft x 7.48
- How to calculate percent removal (BOD and TSS)percent removed = (in - out) / in x 100
- How to convert pressure and head (psi and feet)psi = feet x 0.433 | feet = psi x 2.31
- How to calculate flow rate from volume and timeflow = amount / time