D2 Practice 3 Flashcards
Which device measures the hydrogen ion activity in a solution?
pH meter
What is the purpose of a shaft sleeve in a centrifugal pump?
Protects the sleeve from damage
What is a nutating-disc?
Type of water meter for small-diameter domestic service
What will happen to a steel pipe if the water has low pH?
Corrode
_______ is a disinfection by-product precursor.
Natural organic matter
One of the requirements of the Lead and Copper Rule is for water systems to ______ if the action levels for lead or copper are exceeded (based on 90th percentile of tap water samples).
Install corrosion control
If chlorine was added to water, but there is no chlorine residual, what is true?
Chlorine demand has not been met
Which following is a parasite and microbiological contaminant?
Iron, Nitrate, Giardia, Arsenic
Giardia
What is a typical characteristic of surface water?
Surface Water contains more microorganisms and less minerals than groundwater.
If groundwater is under the direct influence of surface water, how could the surface water affect the quality of groundwater?
Increases microorganisms and turbidity
What is an advantage of using a flex-coupling on a pump?
Allows for a slight shaft misalignment between the pump and motor
What could happen if a valve is closed too quickly?
Water hammer
Which terminology refers to a well under pressure?
Artesian well
What is the typical strength of bulk sodium hypochlorite solution for disinfecting a water supple?
12.5%
What is required if you drop a sample container and the lid?
Get a new container and lid
Why is trihalomethane considered a threat to human health?
Carcinogen
What safety equipment should be used when handling calcium hypochlorite?
Wear rubber gloves, rubber apron, rubber boots, and a face shield
Which document contains information about chemicals, including instructions for safe use and a description of the hazards associated with the chemical?
MSDS or SDS
What following is a disinfection by-product?
Sodium hypochlorite, Calcium hypochlorite, THM, Sodium thiosulfate
THM
What is coliform bacteria?
Indicator organism
How could you minimize the formation of disinfection by-products?
Change the type of disinfectant used
What is the best way to prevent back flow?
Air gap
What is recommended if you encounter a centrifugal pump with a slight leak at the packings?
Do nothing. The slight leak is required to cool and lubricate the packings.
What is the common valve in the water distribution system?
Gate valve
Which disinfectant is less effective than free chlorine residuals but will last a long time in the distribution system?
Chloramine
Which two factors are essential to effectively kill pathogens?
Adequate chlorine residual and contact time
What impact will injecting sodium hypochlorite have on the pH of water?
Increases pH
What is always required before performing any maintenance work on a mechanical or electrical equipment?
Lock-out / tag-out
What is a secondary contaminant?
Contaminant that affects the anesthetics, such as taste color and odor
What is the correct way to disinfect a newly installed water main using the tablet method?
Chlorinated with a dose of 25mg/L, flush out highly chlorinated water from main, and perform bacteriological testing
What is cathodic protection?
Corrosion control to protect metals, such as pipelines and tanks
What is required when replacing a chlorine gas cylinder?
Always use a new lead gasket
What type of hardness can be removed by boiling the water?
Temporary hardness
Iron and manganese are classified as _______
Secondary contaminants
What is used as a preservative for a water sample, collected for lead and copper analysis?
Nitric acid
What is the purpose of priming a pump?
To fully submerge the impeller in water and remove the air inside the pump
Which is a mechanical coupling?
Flange, Victaulic, push-on, Bell and spigot
Victaulic
What is chlorine residual?
Free uncombined and all chlorine compounds with disinfecting properties.
What terminology refers to the depression of water table near a well during pumping?
Cone of depression
What is an aquifer with impermeable layers above and below it?
Confined aquifer
What is the benefit of looping a water main?
Improves water quality and flow
Definition of a public water system
Water system with at least 15 service connections or regularly serves an average of 25 individuals daily for at least 60 days out of the year
What following pH is a strong acid?
1, 6, 8, 13
1
What is used to identify the weaknesses of a water system if a disaster struck and recommends improvements to ensure reliability?
Vulnerability assessment
What is a detailed evaluation of the water source and facilities to ensure the drinking water is protected from all pollution sources?
Sanitary survey
What’s a moderately flexible pipe with smooth interior surface, good flow factor, light weight, and least susceptible to corrosion?
PVC pipe
What would it indicate if the pH of water is 5?
Corrosive
What is a specific capacity of a well?
Well yield per unit of drawdown
What is the purpose of a lantern ring?
Distributes water uniformly around the shaft to provide lubrication and cooling, and provides seal water along the shaft
What is one of the main benefits of using steel pipe in the distribution system?
Strength
What is a preventative maintenence program?
Detecting and correcting problems before equipment breaks down
Which backflow preventer is suitable for any type of cross-connection?
Reduced pressure zone backflow preventer
What best describes a positive displacement water meter?
Measures the volume of water passing through the flowmeter by repeatedly entrapping water in order to measure flow
Which water meter is a pressure-differential type?
Venturi
What is the primary reason for installing a service lateral on a water main at a 45-degree angle?
To prevent sediments and air from entering the service lateral
What is the purpose of installing a tracer wire with a new water main?
To locate the pipe after it has been backfilled
Which water quality parameter(s) must be tested and obtained in the field, immediately after collecting a sample?
Chlorine residual, pH, and temperature
What is the primary purpose of flushing a water main?
Improve water quality
What is breakpoint chlorination?
Addition of chlorine to water until the chlorine demand has been satisfied
Which is the most effective for removing encrustation in a water main?
Pigging, UV, Chlorinating, injecting sodium thiosulfate
Pigging
If coliform bacteria is found in the water supply, what is most likely true?
Pathogens may also be in the water supply
What is the most common disinfectant used in the water industry?
Free chlorine
Which valve is used to release small pockets of air that gather at the high points of a pipeline?
Air release valve
What is a water table?
Upper water surface of an unconfined aquifer
What is applied to a new sample bottle in the field, before you collect a sample for total coliform?
Do nothing, new sample bottles are ready for use.
What is true when collecting a sample for biological contaminants, such as total coliform?
Leave a one inch gap at the top of the bottle
What is the action level for lead?
0.015 mg/L
What could be used to increase alkalinity?
Calcium carbonate (CaCO3)
If you are an attendant for a confined space entry, and notice that the authorized entrant needs assistance to evacuate the space, what’s your immediate response?
Summon rescue
What causes Blue Baby Syndrome?
Nitrate
What is the radius of influence?
The radial distance from the center of the well to the point where there is no lowering of the water table
What best describes pumping water level?
The water level in a well when the pump is in operstion
What best describes static water level?
The water level in a well when the pump is off
What is a single sample of water, collected at a particular time and place?
Grab sample
What is used to regulate the levels of iron and manganese in drinking water?
SMCL
How long should you wait before you test a water sample for chlorine residual?
It must be tested immediately
Which terminology refers to disease-causing microorganisms?
Pathogens
What is alkalinity?
The capacity of water to neutralize an acid
Drinking water standards are based on ________
Maximum Contaminant Level
The Public Notification Rule requires a public water system to notify their customers regarding a(n) _______ as soon as practical, but no later than 24 hours after the public water system learns of the violation.
Acute violation
Which rule was implemented to improve public health protection by reducing fecal pathogens to minimal levels in the drinking water supply?
Total Coliform Rule
What is one of the requirements when a routine water sample tests positive for total coliform?
Collect a repeat sample from the same tap as the original sample. Additionally collect a repeat sample within 5 services upstream and a repeat sample within 5 services downstream of the same tap as the original sample
Which terminology refers to the trickling of water from ground surface to the aquifer?
Percolation
What is the differemce between MCL and SMCL?
MCLs are for substances that pose a threat to human health,while SMCLs are for those that affect the aesthetic qualities of drinking water
What could be implemented to control and minimize corrosion?
Increase pH
