T2 Prac 1 Flashcards
What is removed at the raw water intake?
Fish and debris
What is more likely to be found in groundwater?
Minerals
What is most commonly used to control algae growth in reservoirs?
Copper sulfate
What are common filtration rates in gravity filtration?
2 to 10 GPM/sq.ft.
Leakage within a centrifugal pump is intended for what purpose?
Cool moving parts
Definition of a grab sample
A single sample of water collected at a particular time and place which represents the composition of the water only at that time and place.
Adding sodium hypochlorite to water will have what effect?
Increase pH
What is the purpose of the Groundwater Rule?
To protect the groundwater from disease-causing microorganisms.
What is true about the Total Coliform Rule?
Establishes an MCL based on the presence and absence of total coliform or E. coli
What will happen to water quality if chlorine is injected at the same location as power activated carbon (PAC)?
Chlorine will react with carbon and neutralize the effects of both.
What will react with chlorine to form Trihalomethane?
Natural organic matter
What type of pump has a piston within the casing?
Reciprocating
What must be located near a hazardous chemical storage room?
SDS (safety data sheet)
What term describes the depression of a water table?
Cone of depression
What is the radius of influence?
The radial distance from the center of a well bore to the point where there is no lowering on the water table.
What is the best way to monitor filter performance?
Turbidity
What causes the water to look cloudy?
Suspended material
What chemical is sprayed near a chlorine gas leak to produce a white smoke?
Ammonia
Which water sampling parameters must be taken in the field?
pH and temperature
If the total coliform tests positive, then what must be done next?
Test for fecal coliform
What is performed to evaluate suspectibility to potential threats and identify corrective actions that can reduce or mitigate the risk for a water system?
Vulnerability assessment
What is the definition of holding time for water samples?
The length of time a water sample is retained between taking the sample and laboratory analysis
From a bacteriological standpoint, what is important for a well?
Protect it from contaminated runoff
Which is true of chlorine gas?
Its 2.5x heavier than air
What happens after breakpoint chlorination is achieved?
Chlorine dose and residual increase at the same rate.
If chlorine residual is not detected after 3 mg/l of dosage is applied, then what might be occurring in the water?
Demand has not been met
Which of the following is an indicator organism for pathogens?
Coliform
What would happen if there is an increase in turbidity, organics, and manganese in the water?
Increase in chlorine demand
Which of the following would increase alkalinity in the water?
CaCO³ (calcium carbonate)
If you dropped the lid of a sample bottle prior to sampling, what should you do?
Use a new container
What is the purpose of the lantern ring in a centrifugal pump?
Provide lubrication and cooling
What is the definition of well draw down?
Distance between static and pumping water level
What should be done with a water sample that can not be analyzed in a timely manner?
Refrigerate it
What source water would most likely contain Cryptosporidium and Giardia?
Stream
What is the purpose of chlorine residual?
Provides a safeguard to kill additional microorganisms encountered after treatment
What is the equivalent to 3 log removal?
99.9%
How is turbidity measured?
Nephelometric
Which chemical is used to dechlorinate water?
Sodium thiosulfate
What must you wear prior to being exposed to chlorine gas?
Self-contained breathing apparatus (SCBA)
What is the minimum chlorine concentration required prior to introducing the effluent from a surface water filtration plant to the distribution system?
0.2 ppm
What best describes a water table?
Upper water surface of an aquifer
The Total Coliform Rule applies to what water system?
All public water systems
What is the purpose of a shaft sleeve in a pump?
Protects shaft from wear at stuffing box
Why isn’t chlorine injected immediately prior to filtration?
Increases THMs
Which of the following is a disinfection by-product?
Trihalomethane
What is used to describe a well that is under pressure?
Artesian well
What would cause high concentration of nitrate in groundwater?
Over-fertilization of land
What is the purpose of Lead and Copper Rule?
Protect the public health by minimizing lead and copper in drinking water primarily by reducing water corrosivity
What is not affected by chlorine dose?
Hardness
How long should you run the water before you grab a water sample?
2 to 3 minutes
What is a typical form of calcium hypochlorite?
65% solid tablet
Frosting around the outlet connection of a chlorine gas cylinder indicates what?
Reduced flow of chlorine gas
What describes trickling of water from the ground surface towards the aquifer?
Percolation
What is a likely discharge of industrial waste found in surface water?
Organic solvents
Why shouldn’t you have zero pressure in a water main?
Back siphonage may contaminate the water main
What should be inside a sample bottle when obtaining a sample for a coliform test?
Sodium thiosulfate
If the MCL for a constituent is violated, who is responsible for notifying the customers about this?
Water purveyor
What is the typical concentration of sodium hypochlorite?
12.5%
Is 2.5 mg/l of chlorine is dosed, and there is .5 mg/l of residual, what is the reason for the residual?
The residual is a safeguard for unanticipated chlorine demand in the distribution system
What must always be done before repairing a pump?
Lock out equipment
What is least likely to affect the effectiveness of chlorine?
Sodium
What is considered safe to drink?
No pathogens
Which reading must be taken in the field when obtaining a sample?
Chlorine residual
What device will give you the hydrogen ion concentration?
pH meter
What is a correct laboratory procedure?
Add acid to water
When dealing with a high pressure pipeline, what must you do?
Open and close valve slowly
What water source is more likely to have iron and manganese?
Groundwater
What will affect chlorine demand the most?
Turbidity and organics
What will make chlorine more effective in water?
Moderate increase in temperature
What are colloidal particles?
Very small particles that do not dissolve and remain dispersed in a liquid for a long time due to their small size and electrical charge
What is alkalinity?
The capacity of water to neutralize acid
What does MCL stand for?
Maximum Contaminant Level
What is in the zone of saturation?
Aquifer
What is a hydrologic cycle?
Continuous movement of water throughout the planet
What typically occurs at the beginning of a breakpoint chlorination curve?
Chlorine destroyed by reducing compounds
What is the drawback of pre-chlorination?
Formation of THMs
How long should the tap remain turned off before grabbing a sample for a lead and copper test?
6 hours
The secondary MCL is set for what purpose?
Aesthetic
What will lead to an illness?
Nitrate
What is the most likely cause of decreasing chlorine residual on the water main?
Bacteria and organics may be present
What is the aquifer typically composed of?
Sand and gravel
What is used to lower pH in water?
CO2, carbon dioxide
What is the maximum allowable chlorine residual concentration in the distribution main?
4 mg/l
Why is Trihalomethane considered to be harmful?
It is a carcinogen
What describes turbidity?
Cloudiness or haziness of a fluid caused by suspended solids
