Coagulation and Flocculation
the lower the ____ the more difficult it is to form proper floc?
tubidity
Filter tanks are typically what shape? And what material?
rectangular and concrete
What is an element with different numbers of neutrons?
isotope
PAC is primarly used to control ____
taste and odor
When does aeration happen in the water treatment process?
first
What is the biggest difference between coagulation and flocculation?
mixing speed (slow for floc and quick for coag)
Direct filtration does not have what step?
sedimentation
When looking at Ca(HCO3)2, how many oxygen atoms are there?
6
Which form of activated carbon has a faster absorption rate?
PAC
Which of the aerators is shaped like a set of stairs?
cascade aerator
Which lab test helps determine the effectiveness of multiple types and doses of coagulants?
Jar test
How do you clean a slow sand filter?
shovel off the top few inches
What compound is created with a combination of acids and bases?
salts
What is the biggest difference between granular activated carbon (GAC) and powder activated carbon (PAC)?
GAC is reusable, while PAC is disposable
An induced draft aerator has water and air traveling in ____ directions?
opposite
What is the optimal PH range for the removal of particulate matter when using alum as a coagulant?
neutral PH (6.5-7.2)
What is the layer of solids and biological growth that forms on the top of the filter media?
Schmutzdecke
A molecule that has both a positive and a negative charged site for other ions to attach?
Nonionic polymer
Which is more cost-effective for continuous long-term treatment for taste and odor?
GAC
What is the point of all the "wiffle balls" in a packed tower?
maximizing surface area
Which force will pull particles together once they have been destabilized in the coagulation/flocculation process?
Van der waals force
In a typical air scour sequence, is air applied before or after backwash water is introduced?
before
What type of atomic bond forms when electrons are shared by more than one element?
covalent
What happens to the surface of the PAC particle when they are coated with coagulants or other water treatment chemicals?
they lose their capacity to absorb
What is the normal air-to-water ratio at peak flow in a packed tower aerator?
25:1