yay filters
What is Lena's least favorite filter discussed in the video and why
bag filter- do not enjoy cleaning them
What is the goal of a coarse screen
It is used as a prefilter to help keep debris/ particulates out of the pump
Name two examples of coarse screens
strainer basket, intake screen
What is a popular material that is starting to replace the sand in sand filters
Glass
What is the goal of mechanical filtration?
To remove solids or to remove organic carbons
What is a pro and con of a cartridge filter
Pro: Pressurized, can be used for fine filtration (<1 um), low tech, inexpensive
Cons: frequent cleaning, can clog easy
Name a pro and con of a rotating drum
Pro: Very efficient ( POM>40 um), customizable, minimal labor due to self cleaning, small footprint compared to how much water flows through them
Cons: Very expensive, Need to use water for a backwash
What is a pro and con of bag filter
Pros: Gravity-driven, customizable, low-tech, inexpensive
Con: Frequent cleaning, can clog easily
Name a pro and con of a Hydrocyclones?
Pros: Very efficient ( POM > 75 um), small footprint
Cons: Poor removal of POM <100 um, expensive
Name the 3 sources of organic matter
Living organism- biofloc
Detritus- uneaten food, feces, dead organisms
When would you use a cartrige filter over a bag filter?
Use cartridge filters on water that must be very very pure and clean
How does a sediment basin work?
Water flows in from the bottom and has to climb up over a hill before it can continue on to the exit
The large particles are unable to climb up over the area so the particulates will settle out in the waste collection area
Name a pro and con of a sand filter
Pro: Very efficient, reliable, inexpensive
Cons: Have to backwash them, pressure loss- adds a lot of head to your system
Name a pro and con of a bead filter
Pro: Doubles as a biofilter, less water used compared to a sand filter, less pressure loss compared to sand filters
Cons: uses water for a backwash and expensive
Name two groups of organic matter
Particulate organic matter
Dissolved Organic Matter
How does a cartridge filter work?
Water enters the cartridge filter and passes through the cartridge and the water exits
How does a bag filter work?
Water enters and flow through the bag, solids get trapped and water exits the bag
How does a bead filter work?
Water travels into the filter and must pass the beads and then leaves
Name one pro and one con to sediment basins
Pro: Simple, little energy input, inexpensive, easy to operate
Cons: low hydraulic loading rate- needs low flow rate, need a large footprint, can not remove POM <100 microns, possibility for resuspension
List the types of mechanical filtration in order from smallest to largest based on the particle size range they can remove
Fractionation
cartridge filter
granular filter
microscreens
sedimentation
coarse screen
What is fractionation
A way to get dissolved particles out of the water
How does a rotating drum filter work?
It is a rotating screen filter. Water is brought in and filled up to the screen and the only way the water can exit is to fall through the screen with gravity. As the screen starts to clog up, the water level rises and rises until it flips a switch which causes the screen to rotate which then give the water new screen to pass through. The screen is cleaned from a sprayer that sprays off the detritus into a basket.
How does a hydrocyclone work?
water enters the hydrocyclone and creates a vortex. The water travels through a prescreen and heavy particulates settle out before they have the chance to exit with the water
How does a sand filter work?
The filter is filled about half way up with sand. water enter through the top passes through the sand passed a screen at the bottom is pushed back up through a pipe and leaves the filter
What does type of colloidal matter refer to? and what particle size does it refer to?
Fine particulate organic matter
Microscopic or insoluble/soluble particles that are suspended in the water column
0.001-1 micron