This is an automated archive.

The original was posted on /r/askscience by /u/CommandIndependent57 on 2023-09-29 19:46:48+00:00.

I’m a wastewater operator. We have grit channels that are designed to aerate water to lower the density of incoming wastewater so that anything solid (sand, egg shells, ashes…) can fall out and be collected. Our governing body and manuals state “a properly aerated grit channel will remove up to 100% of grit” but nobody can tell us what “properly aerated” means. We are told that grit needs to move 0.5-1.0 feet per second through the channel but there is no way to measure that because the aeration creates turbulence across the water. Besides trial and error the only control option we have is dissolved oxygen content. So scientists of this app please tell me, at what dissolved oxygen in mg/L does the density of water change? It would be nice to get the density below 0.8 g/cm3 so all grit can be removed early in the process to prevent damage to my pumps and pipes and not have to be removed manually later by shovels hoses and vactor trucks.