“No, I mean skimmers and separators on the intakes. I’m not talking about a visual measurement.”
Whatever quality of water goes into the plant cooling system comes out more polluted because of equipment leaks...nothing is a 100%.
You can’t see this with the naked eye.
The reject of the separators, skimmers and filters GO BACK INTO THE RIVER OR CANAL.
End result:
The quality of water upstream separating equipment = the quality of water downstream effluent out of the plant + the quality of back wash water from the separating equipment + tiny (hopefully) chemical leakage under allowable limits.
The above is a simple Material Balance in general. Other things like effluent temperature that could affect the River Eco System, exaggerated by the wild EPA, is a different story that’s not discussed here.
The above is the nuts and bolts. Where you look at or measure the quality of water all depends on the point in the River or the canal.
The reject of the separators, skimmers and filters GO BACK INTO THE RIVER OR CANAL.
- - - -
Your assumption is false. It is feed into the process and waste streams of the plant. Just as our storm water inside the plant boundaries.