T2 Prac 3 Flashcards
What is the criteria for a community water system?
Has at least 15 service connections used by all-year residents or regularly serves at least 25 all-year residents
What is the acceptable limit of copper in drinking water?
1.3 mg/l
Which type of reservoir is rich in nutrients?
Eutrophic
What is a mechanical seal?
Metallic flat surfaces used to minimize leakage around the pump shaft
What is a confined aquifer?
An aquifer that is bounded above and below by confining beds
What best describes pumping water level in a well?
Upper surface of the groundwater that is being pumped
What is the name of the deepest layer of a reservoir under thermal stratification?
Hypolimnion
What is the health effect of consuming water with high levels of copper?
Stomach and intestinal distress such as nausea, vomiting, diarrhea and stomach cramps
What best describes a turbine pump?
A centrifugal pump that is mainly used to pump water from wells
What is typically used to clean the sludge on the bottom of a rectangular clarifier?
Chain and flight collectors
How often should preventative maintenance be performed on equipment?
Use manufacturer’s recommendation
What is CT?
Contact time X chlorine residual concentration
What is absorption?
Constituent is sucked in
What is the purpose of a check valve?
Allows water to flow in one direction and prevents reverse flow
What would happen to the pH of water if lime was added?
Increases pH
What is the term used to describe groundwater that flows naturally from the ground?
Spring
Once thermal stratification occurs in the middle and lower zones of a reservoir, what type of problem occurs in these layers?
Depletion of total dissolved oxygen
What is the most critical problem that may be encountered when entering a confined space?
Oxygen deficiency and toxic gas
What is a settleable solid?
Sand
What is not a commonly-used coagulant?
Sodium hypochlorite
What is the purpose of a coagulant aid?
Add density to slow settling flows and add toughness to the flocs
What is the purpose of a coagulant (not coagulant aid)?
Neutralize electrical charge
What is least likely to be removed in the sedimentation process?
Aqueous form of manganese
In the sedimentation process, what would happen if the flowrate were increased?
Lower efficiency
If turbidity is rising rapidly what should you do?
Verify the effectiveness of the coagulant chemicals and dosage at the flash mixer
The collection of a bad sample is as useful as what?
No result
What is not a mechanism that occurs in the filter media?
Precipitation
What is not a type of filter media used for gravity filtration?
Diatomaceous earth
What are the 3 types of media used in a multi-media filtration system?
Sand, anthracite coal, and garnet
What does “fluidized” mean in filtration?
Filter media is expanded during backwash
What is not an attribute of activated carbon?
Removes nitrate
How is filtration efficiency evaluated?
Turbidity measurement
What is not a way to address backwashing problems in a filter?
Adjust chemical injection rate
What is a requirement of the Surface Water Treatment Rule?
At least 99.9% removal of Giardia cysts
What is not a process that will remove pathogens from water?
Screening
What will be formed when free chlorine combines with water?
Hypochlorous acid
What is true about chlorine gas by itself?
Non-flammable and nonexplosive
What is the most common source of waterborne disease outbreaks?
Backflow
Why would a water utility switch from using sodium hypochlorite to chloramines?
Reduce formation of THMs
What is a CT value?
A measure of the degree of pathogenic inactivation
When is a hypochlorinator typically used?
To feed liquid chlorine
Which contaminant should never be sampled using a composite sample?
Bacteria
If liquid chlorine is leaking from a cylinder what should you do?
Turn container so that the leak is on top
What provides the most convenient and repeatable chlorine residual results?
Amperometric titration
What does not have a primary MCL?
Iron
What is not true about chlorine gas?
Most people cannot detect chlorine gas at about 2 ppm
What is the disadvantage of using ozone to disinfect water?
Cost
What is the most common technique used to control taste and odor?
PAC
What does an organic compound always contain?
Carbon
What is a type of acid?
Hydrochloric
What would violate the basic rules of laboratory work?
Pipet hazardous materials with your mouth
What is true regarding water sampling?
Collecting samples at a water treatment plant is no different than collecting samples from a stream or river
What has a rotten egg smell?
Hydrogen sulfide
What total coliform bacteria test involves the use of lauryl tryptose broth?
Multiple tube fermentation method
How is aklanity usually expressed?
Calcium carbonate equivalents
What does a pH of 2 represent?
Strong acid
What impact does Total Dissolved Solids (TDS) have on water quality?
Adverse taste
What is the optimum pH of water for disinfecting bacteria?
7.5
What is wire-to-water efficiency?
The combine efficiency of a pump and motor
What is not a type of positive displacement pump?
Centrifugal
What rotates at a high speed and imparts velocity to the water?
Impeller
What is the term used to describe the shallow water of a reservoir with abundant plant growth?
Littoral zone
What term is used to describe a connection between a drinking water system and an unapproved water supply?
Cross connection
What impact do algal blooms have on the pH of a reservoir?
Increases pH
What type of charge would you expect to see on a coagulant?
Positive
What would cause excessive media to be in the spent backwash water?
Backwashing at high velocity
What safety equipment must be worn before entering a confined space?
Harness
What are typical characteristics of the source water for a direct filtration plant?
Low turbidity level, less than 2 NTU
What is the purpose of the coagulation and flocculation process?
Neutralize the negative charges on the colloids, and slowly stir water to create flocs
What would not trigger a filtration system to backwash?
Temperature
What is the definition of disinfection?
Inactivation of most pathogens
What is a secondary contaminant?
Manganese
What is the safety hazard of working with polymers?
Slippery floors
What is the disadvantage of using chloramines?
Weak disinfectant
What is the purpose of a dial indicator?
Measure shaft misalignment
What is an attribute of a diatomaceous earth filter?
Mesh screen is pre-coated with powdered media
What is true about the presumptive test?
It takes 48 hrs to obtain results for the total coliform test
What is a carcinogen?
Causes cancer
What is the minimum required disinfection residual concentration leaving a surface water treatment plant?
.2 mg/l
What is equal to 1 ppm?
1 mg/l
What is the disadvantage of using UV to disinfect water?
No disinfectant residual
What would most likely occur if a higher quantity of chlorine is added to water?
More THMs will form
What is the most common error in water quality analysis?
Sampling
What is the term used to describe the introduction into water of microorganisms, chemicals, and toxic substances in a concentration that makes the water unfit for its next intended use?
Contamination
What acid is formed when chlorine is mixed with water?
Hypochlorous acid
