L7 - Water Quality Modifications Flashcards
By what means can contaminants in water be remove?
-physical
-chemical
-biological
Types of contaminants found in water
-Floating and suspended materials
-Colloidal Materials
-Dissolved Materials
-Dissolved gases
-Immiscible Liquids
Flow Sheet
Used to describe the specific combination of operations and processes for a treatment
Screening and grit removal(SW)
Removes relatively large floating and suspended debris and the sand
and grit that settles very rapidly which may damage equipment.
Primary sedimentation (also
known as settling or clarification)(SW)
Removes the particles that will settle out by gravity alone within a few
hours
Rapid mixing (SW)
Uses chemicals and agitation to encourage suspended particles to
collide and adhere into larger particles.
Flocculation(SW)
Gently mixes the water, encourages the formation of large particles of
floc that will more easily settle.
Secondary settling(SW)
Slows the flow enough that gravity will cause the floc to settle.
Filtration(SW)
Removes particles and floc that are too small or light to settle by
gravity.
Sludge processing(SW)
Dewatering and disposing of solids and liquids collected from the
settling tanks
Disinfection(SW)
Provides sufficient time for the added disinfectant to inactivate any
remaining pathogens before the water is distributed.
Aeration (GW)
Removes excess and objectionable gases.
Lime Soda Ash Addition (softening)(GW)
Chemical addition for hardness removal.
Flocculation(GW)
Follows chemical addition, which forces the calcium and
magnesium above their solubility limits and form
precipitates.
Sedimentation(GW)
Removes the hardness particles that will now settle by
gravity.
