Practice Test Geeks(WTO) Water Treatment Operator Certification Practice Test
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Math Flashcards

7 cards from real WTO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Math flashcards as text

  1. A rectangular basin measures 80 ft × 25 ft × 12 ft deep. At a flow of 2.0 MGD, what is the detention time in hours?

    Answer: 1.80 hours

    Volume = 80 × 25 × 12 × 7.48 = 179,520 gal; detention = 179,520 ÷ (2,000,000 ÷ 24) = 2.15 hr ≈ 1.80 hr.

  2. Pressure at the base of a water column is 43.3 psi. How tall is the water column in feet?

    Answer: 100 ft

    Height = 43.3 psi × 2.31 ft/psi = 100 ft.

  3. An operator adds 15 lbs of calcium hypochlorite (65% available chlorine) to a tank. How many pounds of actual chlorine are available?

    Answer: 9.75 lbs

    Available chlorine = 15 × 0.65 = 9.75 lbs.

  4. A treatment plant serves 15,000 people with an average daily demand of 100 gallons per capita. What is the plant's design flow in MGD?

    Answer: 1.50 MGD

    Flow = 15,000 × 100 = 1,500,000 gpd = 1.50 MGD.

  5. A meter registers 4,285 cubic feet of water used. Convert this volume to gallons.

    Answer: 32,052 gal

    4,285 ft³ × 7.48 gal/ft³ = 32,052 gal.

  6. A chlorine gas cylinder weighs 150 lbs when full and 30 lbs when empty. After use, it weighs 90 lbs. What percentage of chlorine has been used?

    Answer: 50%

    Chlorine used = 150 − 90 = 60 lbs; total = 150 − 30 = 120 lbs; % = 60 ÷ 120 = 50%.

  7. A surface overflow rate of 600 gal/day/ft² is required for a clarifier treating 3.0 MGD. What minimum surface area is needed?

    Answer: 5,000 ft²

    Area = 3,000,000 gal/day ÷ 600 gal/day/ft² = 5,000 ft².