[SimoneMeyer]

They've given me six steps in water purification and asked that I classify them under physical or chemical changes. I've done that but would like to know if how I have classified them is correct.

Physical:
A rudimentary filter made of metal bars is used to filter large particles and waste, like cans and bottles

Flocculation (addition of aluminum sulfate and lime)

Vaporize the water in air.


Chemical:

Adding chlorine to the water in order to kill bacteria and virus.

Passing the water through a gavel bed and sand in a filtration reservoir.

A second chlorine treatment to kill any leftover bacteria.

Thank you!

[Ida Isotope]

I think flocculation would be chemical and I think passing the water through a gavel bed and sand in a filtration resevoir would be chemical.

Chemical would actually change the original product and physical would not.

[billnotgatez]

I think there is a typo here

I think passing the water through a gavel bed and sand in a filtration resevoir would be chemical.

[Ida Isotope]

Is they typo gravel bed? Or is it physical and should be chemical. I'm not sure what a gavel bed is and I assume filtration resevoir is just filtering.

Do tell?

[Borek]

I think passing the water through a gavel bed and sand in a filtration resevoir would be chemical.

Physical. You may think about gravel as just a thick sand, so thick, that you no longer call it sand

[SimoneMeyer]

Sorry, yes. I typed gravel incorrectly. My apologies.

[Ida Isotope]

I think passing the water through a gavel bed and sand in a filtration resevoir would be chemical.

Physical. You may think about gravel as just a thick sand, so thick, that you no longer call it sand

So if this was the case you are saying?? I'm lost. Maybe I'm not sure what gravel is. Isn't it a bunch of rocks? Even if it was a thick sand wouldn't that just mean that less water got through it but it is still water?

Or is there mud in gravel as well?

I can't believe this but I don't think I know what gravel actually is!!!!

[Borek]

Isn't it a bunch of rocks?

Small rocks, you may think about it this way. Gravel is used for filtering, just like sand. The only difference is that sand is used for removing fine particles, gravel for large ones.

[billnotgatez]

The dictionary is a good source if you do not know the meaning of a word.

Gravel
–Noun 1. Small stones and pebbles, or a mixture of these with sand.

[AceParkle]

I think sand and gravel are physical filtration media because it does not change in the process. It is typical used in many companies because it is known in removal properties and low acid solubility.

[Jesica23]

Are the steps in RO filtration system based on chemicals?