Water Distribution Grades 3 & 4 Flashcards
(173 cards)
If a water system collects at least 40 samples per month for analysis of total coliforms, what percentage of total coliform positive samples are acceptable for the system to remain in compliance with the maximum contaminant level for total coliforms?
a. No more than 2%
b. No more than 3%
c. No more than 4%
d. No more than 5%
d. No more than 5%
Water systems are required to achieve at least _____ removal and/or inactivation of viruses between a point where raw water is not subject to recontamination by surface water and a point downstream before, or at the first customer.
a. 2-log
b. 2.5-log
c. 3-log
d. 4-log
d. 4-log
Continuous chlorine residual monitoring is required where the water enters the distribution system under the Surface Water Treatment Rule when the
a. population served is greater than the 3,300 people.
b. population served is greater than 10,000 people.
c. number of taps is greater than 1,000 people.
d. number of taps in less than 2,500 people.
a. population served is greater than 3,300 people.
A community water system must post the Consumer Confidence Report on a publicly accessible website if it serves more than
a. 10,000 people.
b. 25,000 people.
c. 50,000 people.
d. 100,000 people.
d. 100,000 people.
Public water systems that cannot meet the required removal of total organic compounds (TOCs) can comply if their source-water TOC level is _____, calculated quarterly as a running annual average.
a. less than 1.0 mg/L
b. less than 2.0 mg/L
c. less than 2.5 mg/L
d. less than 5.0 mg/L
b. less than 2.0 mg/L
The Surface Water Treatment Rule does not specify which of the following treatment technology?
a. Conventional filtration
b. Membranes
c. Slow sand filtration
d. Chloramine disinfection
d. Chloramine disinfection
A regulated organic contaminant concentration that exceeds the MCL
is a Tier 1 violation requiring public notification within 24 hours.
b. is a Tier 2 violation requiring public notification within 30 days.
c. is a Tier 3 violation requiring public notification within 10 months.
d. does not require public notification.
b. is a Tier 2 violation requiring public notification within 30 days.
A water system using conventional filtration treatment does not have to use enhanced coagulation to achieve the total organic carbon (TOC) percent removal if
a. the total trihalomethanes running annual average is lee than or equal to 0.030 mg/L.
b. the sum of haloacetic acids is less than or equal to 0.040 mg/L.
c. the treated water quarterly running average TOC is less than 4.0 mg/L.
d. the treated water quarterly running average TOC is less than 2.0 mg/L.
d. the treated water quarterly running average TOC is less than 2.0 mg/L.
Operators must balance satisfying regulations on the amount of certain chlorinated organic compounds with
a. controlling water hardness.
b. meeting disinfection limits.
c. keeping turbidity below 0.1 ntu.
d. reducing iron levels below the MCL.
b. meeting disinfection limits.
Regulations that govern the US water supply and treatment are developed by the US Environmental Protection Agency’s primary standards under what act?
The Safe Drinking Water Act (SDWA)
What term refers to the highest level of a disinfectant that is allowed in drinking water?
Maximum Residual Disinfectant Level (MRDL)
According to the US Environmental Protection Agency’s primary drinking water standards, what is the maximum contaminant level for alpha particles?
1.5 pCi/L
What is the maximum contaminant level for arsenic?
10 ug/L
What is plotted on the horizontal scale (x-axis) of a pump curve?
a. Efficiency
b. Capacity (flow rate)
c. Total head
d. Power
b. Capacity (flow rate)
The ____ is the outlet, or high-pressure side of a pump.
a. suction side
b. flow gauge
c. piezometer
d. discharge side
d. discharge side
What is the term for the amount of energy used by water moving from one location to another?
Head loss
What is the formula for calculating chlorine demand?
Chlorine Demand, mg/L = Chlorine Dosage, mg/L - Chlorine Residual, mg/L
How is wire-to-water efficiency obtained?
By Multiplying the Motor and Pump Efficiencies together.
What is the formula to convert milligrams-to-liter concentration to pounds per day?
Feed Rate, lbs/day = Dosage x Flow Rate x Conversion Factor
Which type of distribution system configuration has smaller mains that generally terminate as dead ends?
a. Grid system
b. Dendritic system
c. Arterial-loop system
d. Tree system
Tree system
The pressure during fire flow conditions should NOT drop below
a. 15 psi
b. 20 psi
c. 25 psi
d. 30 psi
b. 20 psi
How many times higher than the normal operating pressure should the pressure rating of distribution system piping be?
a. 1.0 - 2.0 times
b. 2.5 - 4.0 times
c. 4.0 - 5.0 times
d. 5.0 - 7.0 times
b. 2.5 - 4.0 times
Regarding fire flow, mains smaller than 6 inch should be used only
a. in residential areas.
b. in low-value districts.
c. in rural areas.
d. to complete a grid.
d. to complete a grid.
What is the commonly accepted water velocity in water mains at maximum flow?
a. 1 - 3 ft/sec
b. 2 - 4 ft/sec
c. 4 - 5 ft/sec
d. 5 - 6 ft/sec
b. 2 - 4 ft/sec