system
Given the following post, respond as if you're commenting on Reddit:
human
[ALOK] how could you keep a highly skilled water bender like Ming Hua in jail? They need water to live, and they could use even small amounts of water/blood bending to escape.

Not sure if Ming Hua can blood bend, but we've seen what skilled water benders can do with even small amounts of water or their own sweat. In the Avatar universe, how would it be possible to arrest and incarcerate a very skilled water bender? If you don't give them any liquid, they die. Would you have to execute all water benders like this? Could you keep them in some type of cell that was impossible to cut through? I imagine good water benders could break any lock by inserting water into it then freezing that water, causing it to expand and cracking the lock open. I suppose you could remove their bending, but so far only two people (whoever the avatar is at the time and Amon) can do that.
gpt
By doing exactly what they did, throwing her somewhere hot and dry enough that she couldn't accumulate any meaningful amount of water to do anything serious and physically isolated enough that escaping would be difficult, and having highly trained guards keep an eye on her.

>If you don't give them any liquid, they die.

She'd been there for years, they're obviously giving her enough to survive

> In the Avatar universe, how would it be possible to arrest and incarcerate a very skilled water bender?

Knock em  out, restrain their movements so they can't bend, lots of ways

>Could you keep them in some type of cell that was impossible to cut through? 

Why not cripple/disable their ability to cut shit in the first place, which the volcano prison accomplished?