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