Drinking Water Flashcards
The discharge from filters flows into a storage reservoir also called a
a Clearwell
What technique is effective at removing 50 to 95% of the algae that is from the influent water
microstrainer
Which of the followING is needed to determine the minimum fire suppression storage?
required fire flow rate and the duration of fire flow rate
what are the four main zones of the settling tank
inlet, sludge, settling and outlet
Which of the following types of settling occurs when individual particles settle independently
Discrete
which of the following terms describes the surface charge that the sub-micron particles carry that cause them to repel each other so they cannot collect to form larger particles
Colloidal***
Which of the Following terms describes the pH at which the zeta potential of the particle is zero
Iso-electric point
Paddles are used to gently mix the water in the flocculator, Which is greater the velocity of the paddle or the velocity of the water?
Velocity of the paddle - this is because of the slip the slip is represented by the factor k in the equation for the water velocity
what is the most basic test used on the effectiveness of coagulation/ flocculation
jar test
Once coagulant has ben added to the treated water, the particles become net neutral. What is the forces acting to attract the particles that no net charge?
VAn der Waal forces are weak forces that work to attract particles together that have no charge
As alkalinity increases, what happens to the capacity of the water to neutralize acids
Increases - Alkalinity is the measure of how well a sample can neutralize an acid. The more alkalinity in water, the better the water can neutralize acids
What does reverse osmosis accomplish during water treatment?
It is an effective way to remove contaminants, it removes ions, molecules and large particles from drinking water.
what are the 7 basic steps for water treatment?
- Coagulation
- Flocculation
- Sedimentation
- Filtration
- Disinfection
- Storage
- Distribution
What is the purpose of aeration during drinking water treatment?
Aeration during Drinking water treatment is primarily to reduce taste and odor causing compounds in the system.
Where is the storage reservoir typically located on a suite that is also serviced by a pumping station
The storage reservoir will typically by located on the opposite side from the pumping station, During periods of high water consumption, the site can be fed from both sides which decreases the head in the mains.
What is Effective storage
it is total storage minus the dead storage
The presence of methane gas occurs in the groundwater because of the decomposition of organic matter, How is it removed?
Aeration, during the process air is mixed into the water which leads to the has being vented to the outside atmosphere
where are cyanophycean found?
both salt and fresh water, floating near the water surface
what color are cyanophycean?
they are blue-green in color
What is a main culprit of taste and odor complaints?
cyanophycean
Name three methods/ materials used for oxidation
Potassium Permanganate, Chlorine Dioxide and Ozone
What are THMs’?
Trihalomethanes, are the byproducts of the chlorination of water that has natural organic matter present
What is the technical term/ test for the amount of Odor in water
Threshold Odor number/test, determine the amount of odor in the water. During the test dilutions are presented of a sample and the last dilution in which the odor can be detected is called the threshold odor number
What are advantages of powdered activated carbon
Low initial cost and dosage flexibility
What are the disadvantages of powdered activated carbon?
large amount of sludge is produced as it cannot be regenerated
What materials cause salty taste in water
Sodium, Magnesium, Potassium
What is the most common compound used for drinking water treatment in the coagulation process
Alum, or aluminum sulfate is the most common chemicals coagulant used for drinking water treatment in coagulation process
What is the purpose of coagulation?
To remove small particulate matter that is suspended in the influent water
What is tapered flocculation
also called tapered energy - the process with which the amount of flocculation gradually diminishes as the water progresses through
Name two reasons there could be poor floc formation and a test that can be done?
Poor Flocc formation can be a symptom of either an inadequate coagulant dose or improper detention time. These can be tested using a simple jar test to model what the problem is?
Name 3 advantages of UV in disinfection for drinking water?
- does not form harmful by-products
- Does not create an unpleasant taste or odor
- Effective on a large range of pathogens
Name 3 things that help determine the location of a water treatment plant?
Location of location water, Location of power sources, Sewer services for the plant
Name 3 factors used in sizing atmospheric storage tanks?
Emergency reserve storage, future growth of the system, fire flow storage
What is the recommended standby storage for systems served by a single source supply?
two times the average day demand
What does activated carbon mainly attract from liquid and vapor?
organic materials, Activated carbon attracts only a small variety of inorganic chemicals
What chemicals are more likely to produce a rotten egg odor in drinking water
Hydrogen sulfide
What makes a garlic-y taste in water?
Methane
What is something creates a earthy or grassy odors
Geosmin