Measuring amount of settled solids

[ChemGuy2016]

Hello!

Does anybody know of a good method to measure the amount (mass or volume) of settled solids in a settling tank over time?

Thanks

 

[bimr]

https://www.youtube.com/watch?v=_fKGM040wvI

http://www.fondriest.com/environmen...quality/turbidity-sensors-meters-and-methods/

 

[ChemGuy2016]

Thanks for the links. These are for lab scale, but I am wondering about an industrial scale in a 1000 gallon tank. I want to be able to know when the settling process has finished and there is a distinct solid/liquid interface before decanting the supernatant.

 

[jari001]

@ChemGuy2016
In your second post are you saying there is a distinct layer or are you asking if there is a way to determine if there is a distinct solid/liquid interface?

 

[ChemGuy2016]

I want to be able to know when a distinct layer has been formed and there are no more suspended solids in the clear liquid phase. On a lab scale you would do this visually through clear glassware, but the tank is steel and cannot be seen through.

 

[IRstuff]

Is there a numerical criteria for "no more suspended solids?" What numerical criteria do you use with glassware? Are you looking to modify the tank? Could you add sight glasses to the tank?

Do these solids have color? How much depth is expected for the settled solids?

TTFN (ta ta for now)
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[ChemGuy2016]

What about a level sensor that does not detect clear liquids, and then sends out the level of the solid layer? Does such an instrument exist?

 

[IRstuff]

Are these solids or the clear liquid conductive?

You've not answered any of my questions, making it difficult to come up with plausible answers. You need to establish the requirements before you come up with solutions.

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[bimr]

Industrial scale tends to be much larger than a 1000 gallon tank.

The easier way to do this is to use a conical bottom tank and install valves on the side of the tank every 12 inches or so.

You may also use a sludge judge:

https://www.coleparmer.com/i/sludge..._term=1100008783841&utm_content=Lab Equipment

 

[shvet]

I would recommend to try guided radar level meter. Technicaly it can "catch" different types of interfaces: liquid/emulsion, liquid/solid whether floating or sunk. Krohne Optiflex series would be an example.

 

[MortenA]

normally "turbidity" is a measurement for how unclear a liquid is. However, the turbidity meters that i know would usually sample from a pipe. If there is no mixing in the tank (guessing from the fact that its a settling process then i dont know if it will work. However, i would have guessed that in most such processes you would establish a settling time and use that?

 

[Latexman]

Take a look at nuclear level detection from outside the vessel. It may distinguish between high solids and no solids.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[chicopee]

"...and there are no more suspended solids ..." I do not believe that statement will ever happen as larger size particles will settle first and then smaller size particles will settle over a period of time but not totally.