28 Questions
What is the process referred to as when it occurs within the pores?
Flocculation
What happens to the flocs when they are removed from the pores?
They are removed by one of the mechanisms
What is the Arabic term for flocculation?
التلبد
What is the purpose of flocculation in the pores?
To remove impurities from the fluid
What happens to particles when they come into direct contact with the surface of the filtering medium?
They are removed from the stream line
What is the mechanism of removal of flocs from the pores?
One of the mechanisms
What is the term for the process of particles being removed from the stream line when they come into contact with the filtering medium?
Interception
What is the result of particles coming into direct contact with the surface of the filtering medium?
The particles are removed from the stream line
Why do particles get removed from the stream line when they come into contact with the filtering medium?
Because of the direct contact with the surface
What is the primary requirement for particles to be removed from the stream line through interception?
The particles must come into direct contact with the surface
What happens to particles smaller than the pore size during filtration?
They are trapped by chance contact
What is the mechanism by which particles larger than the pore size are removed from the fluid during filtration?
Mechanical straining
What is the result of chance contact between particles and the filter?
Particles are trapped within the filter
Which of the following is NOT a mechanism of particle removal during filtration?
Diffusion
What is the primary mechanism by which particles are removed from the fluid during filtration?
Mechanical straining
What happens to heavy particles that do not follow the flow streams?
They settle on the filtering medium
What is the result of sedimentation or impaction?
Heavy particles settle on the filtering medium
What is the reason for particles settling on the filtering medium?
Because they are heavy and do not follow the flow streams
What determines whether a particle will settle on the filtering medium?
The weight of the particle
What is the relationship between the flow streams and the filtering medium?
They work together to remove particles
What is the primary purpose of depth filtration?
To remove suspended and colloidal particles from water
What is the term for the material used in depth filtration, such as sand or coal?
Granular filter media
What is the name of the process that removes particles from the filter bed?
Backwashing
What is the term for the rate at which water flows through the filter?
Loading rate
What is the primary mechanism of particle removal in depth filtration?
Straining
What type of filter media is used to remove very fine particles?
Metallic mesh
What is the term for the water that has been previously filtered?
Previously filtered water
What is the purpose of the expanded filter bed?
To allow for backwashing
Study Notes
Filtration Process
- Particles moving along the streamline are removed when they come into direct contact with the surface of the filtering medium.
- Interception occurs when particles are removed due to direct contact with the filtering medium.
Flocculation
- Flocculation can occur within the pores of the filtering medium.
- Flocs will be removed by one of the mechanisms of filtration.
Depth Filtration
- Depth filtration involves removing suspended solids and colloids from water by passing it through a layer or bed of granular filter media, such as sand.
- Suspended solids are removed by the filter media.
Filter Classifications
- Filters can be classified based on the filtering medium used:
- Sand filters (e.g., natural silica sand)
- Anthracite filters (e.g., powdered anthracite coal)
- Diatomaceous earth filters
- Metallic mesh filters (e.g., stainless steel mesh)
Filtration Rate
- Filtration rate (or loading rate) is the rate of water flow applied per unit area of the filter.
- It is the velocity of water approaching the filter interface.
Principal Particle Removal Mechanisms
- Sedimentation or impaction: heavy particles that do not follow the flow streams settle on the filtering medium.
- Interception: particles smaller than the pore space are trapped within the filter by chance contact.
- Adhesion: particles are removed due to direct contact with the filtering medium.
Learn about the concept of interception in fluid mechanics, where particles moving along a streamline are removed when they come into direct contact with the surface of a filtering medium.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
