California Water Treatment Operator Exam, Treatment Exam Math: all 42 questions
All questions from the Treatment Exam Math section for California Water Treatment Operator Exam, each with the correct answer.
- 6001A plant treats 2.5 MGD and the chlorine dose is 2.0 mg/L. How many pounds of chlorine are needed per day?
- 6002A well delivers 1.5 MGD and the desired chlorine dose is 3.5 mg/L. How many pounds of chlorine gas are needed per day?
- 6003A plant needs 20 lb/day of available chlorine and uses calcium hypochlorite that is 65 percent available chlorine. How many pounds of the hypochlorite are needed per day?
- 6004A plant treats 3.2 MGD with a chlorine dose of 1.8 mg/L using 12.5 percent sodium hypochlorite. About how many pounds of the hypochlorite solution are needed per day?
- 6005A pump delivers 3,500 gpm. What is the flow in MGD?
- 6006A plant flow of 2.0 MGD is equal to how many gallons per minute?
- 6007A flow of 3 MGD is equal to how many cubic feet per second (cfs)?
- 6008Water flows at 800 gpm through a 12-inch pipe. What is the approximate velocity in ft/sec? (1 cfs = 449 gpm)
- 6009A cylindrical storage tank has a diameter of 40 ft and a water depth of 25 ft. How many gallons are in the tank?
- 6010A clearwell holds 250,000 gallons and the plant flow is 1.2 MGD. What is the detention time?
- 6011A basin holds 30,000 gallons and the flow is 500 gpm. What is the detention time in minutes?
- 6012A well has a specific capacity of 12 gpm per foot of drawdown. If the drawdown is 40 ft, what is the well yield?
- 6013A pump discharge has a head of 150 ft. What is the pressure at the bottom of that column of water in psi?
- 6014The water level in a tank is 28 ft above a pressure gauge. What pressure should the gauge read?
- 6015How many pounds of dry chemical are in 50 gallons of a 10 percent solution, if the solution weighs 8.34 lb/gal?
- 6016A 0.25 percent solution contains how many mg/L of chemical? (1 percent = 10,000 mg/L)
- 601712 lb of dry chemical is dissolved in 100 lb of water. What is the percent strength of the solution?
- 6018How many gallons of a 1 percent solution can be made from 5 gallons of a 12 percent solution?
- 6019A plant treats 2 MGD with a chlorine dose of 2.5 mg/L using 12.5 percent hypochlorite weighing 10 lb/gal. How many gallons per day of solution are needed?
- 6020A chemical feed pump must deliver 33.4 gal/day. What setting in mL/min is needed? (1 gal = 3,785 mL)
- 6021The chlorine demand of a water is 2.3 mg/L. How much chlorine must be fed to leave a 1.0 mg/L residual?
- 6022A plant uses 45 lb/day of chemical that costs $0.85 per pound. What is the daily chemical cost?
- 6023A community of 12,000 people uses 150 gallons per capita per day. What is the average daily demand?
- 6024A filter has an area of 300 sq ft and operates at 4 gpm/sq ft for 24 hours. How many gallons are produced?
- 6025A filter with an area of 250 sq ft is backwashed at 20 gpm/sq ft for 8 minutes. What volume of backwash water is used?
- 6026A backwash rate of 15 gpm/sq ft is equal to a rate of rise of approximately
- 6027A sedimentation basin with a surface area of 2,500 sq ft receives 1.0 MGD. What is the surface loading rate?
- 6028A basin has a total weir length of 150 ft and a flow of 1.2 MGD. What is the weir overflow rate?
- 6029A required CT is 36 mg/L-min and the chlorine residual at the end of the clearwell is 1.5 mg/L. What minimum contact time is needed?
- 6030A pump moves 1,000 gpm against a total head of 99 ft. What is the water horsepower?
- 6031The water horsepower of a pump is 25 hp and the pump efficiency is 80 percent. What is the brake horsepower?
- 6032A pump requires 31.25 brake horsepower and the motor is 90 percent efficient. What motor horsepower is required?
- 6033A 40 hp motor runs 24 hours at an electricity cost of $0.12 per kWh. What is the approximate daily cost? (1 hp = 0.746 kW)
- 6034Water flows at 3 ft/sec through an 8-inch pipe. What is the flow in cubic feet per second?
- 6035A water meter reads 1,245,300 gallons on Monday and 1,578,300 gallons three days later. What is the average daily flow?
- 6036How long will it take to fill a 120,000 gallon tank at 500 gpm?
- 6037A reservoir holds 600,000 gallons. Inflow is 300 gpm and demand is 1,100 gpm. How many hours can the supply last?
- 6038How many pounds of chemical are in 3 MG of water dosed at 4 mg/L?
- 6040Raw water turbidity is 12 NTU and the filtered water is 0.3 NTU. What is the percent removal?
- 6041A reservoir covers 40 acres with an average depth of 12 ft. About how many million gallons does it hold? (1 acre-foot = 325,851 gal)
- 6042How much does 2,500 gallons of water weigh?
- 6043A hardness of 5 mg/L is equal to how many grains per gallon? (1 gpg = 17.1 mg/L)