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Sedimentation
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Tanks
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Maintenance
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and Tips
Maintenance
Cleaning the Sedimentation Tanks
The sedimentation tanks should be cleaned occasionally so that experimental results aren't affected by build-up.
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Tips h3. Maintenance h5. Cleaning the Sed Tanks The sed tanks should be cleaned occasionally so that experimental results aren't affected by build-up. {float:right|border=2px solid black|width=170px} {anchor:Cleaning Pump}[!Cleaning Pump.JPG|thumbnail!|Cleaning Pump.JPG] h5.The Pump Used to Clean Tanks {float} - |
- Plug
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- the
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- pipes
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- going
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- to
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- the
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- sed
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- tanks
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- or
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- shut
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- down
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- the
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- pilot
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- plant
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- so
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- that
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- no
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- water
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- is
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- running
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- to
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- the
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- sed
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- tanks.
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- Open
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- the
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- drains
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- on
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- the
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- bottoms
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- of
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- the
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- tanks
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- and
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- let
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- the
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- water
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- and
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- sludge
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- drain
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- out.
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- While
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- there's
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- still
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- some
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- water
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- in
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- the
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- tank,
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- place
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- the
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- cleaning
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- pump
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- in
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- the
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- tank
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- and
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- drain
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- out
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- the
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- sludge
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- at
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- the
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- bottom
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- of
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- each
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- tank.
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- (Use
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- an
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- extension
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- cord
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- if
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- the
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- pump's
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- power
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- cord
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- can't
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- reach
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- the
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- tank
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- on
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- the
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- right.)
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- Hose
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- down
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- the
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- sides
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- and
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- bottoms
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- of
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- the
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- tanks.
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- For
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- a
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- thorough
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- cleaning,
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- gently
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- remove
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- the
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- effluent
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- launder
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- and
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- clean
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- sludge
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- off
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- the
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- inside
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- and
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- outside.
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- Replace
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- the
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- tubes
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- leading
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- to
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- turbidimeters
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- when
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- they
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- start
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- to
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- look
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- dirty.
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Cleaning
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Turbidimeters
Tips
Determining the height of the sludge blanket
As of early November '08, there's no set way to check the height of the sludge blanket. ("Height" refers to the top of the mass of sludge in the tank.) One way to find the top of the sludge blanket is to shine a flashlight into the tank from the top. Let the beam hit one of the walls and check where it's visible from the outside. Move the beam down and watch the spot of light move down until it stops moving even when you're moving the flashlight. This spot is the top of the sludge blanket. (Since the sludge blocks light, the spot of light is visible only until the beam hits the top of the sludge blanket.)
Lowering the Sludge Blanket with Lamella in the Tank
This can take a while. The sed tank must be carefully drained in intervals when trying to lower the sludge blanket.
- Open the valve a little. Very dirty water should flow out.
- Let water flow until the water is more clear than brown.
- Open the valve a little more and do the same.
- Repeat 1-3 carefully until the water opening the valve further would seem to make the velocity too high. (Pulling sludge out of the tank too fast could disturb the blanket a little. Just use your judgment.)
- Repeat this process every few minutes. If the water coming out is very clear as soon as you open the valve, wait longer between draining periods. (Waiting some time between drainings seems to allow more sludge to flow into the outflow pipe at the bottom of the tank.)