system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are impurities and other garbage taken out of the water inside sewer systems, and what happens to the waste after the water is cleaned?
gpt
I went to a waste treatment plant several years ago and this is what happened:

* The water flows in and is run though a gate. The gate picks out most of the larger stuff, and the flow of the water is slowed occasionally to allow people to clean out the gates. 

* Then the water is run through a grate. Sometimes the water will be run through two or more grates. This will pick up the solid stuff and non-dumpable things that get flushed every so often. Your kid's dead fish will get scooped out here as will your lost diamond ring. 

* Following the grates, the water flows through at least one, and maybe more screens. This is the first stop where your poop gets filtered out. It also filters out condoms, tampons, toilet paper and whatever else gets flushed down. Again, the water flow is adjusted or even diverted to allow for cleaning of the screens. The stuff filtered from the screens may be taken to a landfill. 

* Then the water may get held in a pond for awhile. This allows for anything else that may have founds its way through to drop to the bottom of the pond and be scooped out. 

* The water, at this point will have bacteria added to it. The bacteria will eat whatever organic material is left and then more bacteria is added to eat THAT bacteria. 

* Then you may have the water sprayed over charcoal for one final washing.