Yeah the thing about the closed loop systems is that they pump a shit ton of chems to kill anything in the water. However no matter what shit grows in the loop. So they end up flushing the loop and dumping the water and chems into the sewer, before repeating the process.

So no, closes loop DCs aren't great.

And i literally work in one. Just the other week the DC manager told me they had a leak. A stupid amount of water was lost.

But because water is so cheap for commercial metro users it was more a oops then a wake up. Bare min repairs and bam, back up and running.

The point is these "closed" systems aren't perfect and shit happens. Especially as they age out.