WTO Math 3

Question 1

A filter has a surface area of 400 ft² and a flow rate of 1,600 gpm. What is the filtration rate in gpm/ft²?

Accepted Answer

4 gpm/ft²

Answer

Filtration rate = 1,600 gpm ÷ 400 ft² = 4 gpm/ft².

Question 2

A settling basin is 60 ft long, 20 ft wide, and 10 ft deep. What is its volume in gallons?

Accepted Answer

89,760 gal

Answer

Volume = 60 × 20 × 10 = 12,000 ft³ × 7.48 = 89,760 gallons.

Question 3

The plant flow is 4.2 MGD. Express this flow in gallons per minute (gpm).

Accepted Answer

2,917 gpm

Answer

4.2 × 1,000,000 ÷ 1,440 min/day = 2,917 gpm.

Question 4

A 10% sodium hypochlorite solution is needed to deliver 6 lbs of chlorine. How many gallons of solution are required?

Accepted Answer

7.19 gal

Answer

6 lbs ÷ (0.10 × 8.34 lb/gal) = 6 ÷ 0.834 = 7.19 gallons.

Question 5

A pump runs 14 hours per day and delivers 350 gpm. How many million gallons does it deliver in 30 days?

Accepted Answer

8.82 MGD

Answer

350 × 14 × 60 × 30 = 8,820,000 gal = 8.82 MG total.

(WTO) Water Treatment Operator Certification Practice Test