yes, unless they’re the only thing on the line, as the public toilets (location of the odor problem) are...
“yes, unless they’re the only thing on the line, as the public toilets (location of the odor problem) are...”
No. The toilets are hooked up to the main...there isn’t a special network of toilets only sewer in SF.
One of my duties as a civil engineer is to design sewer lines. You cited the 2 fps rule earlier. Take a look at the dead end manhole at the high end of any line. The velocity will be much less than 2 fps. In general, I have discovered that you have to accumulate 4-5 houses to get 2 fps, even if the sewer is at 8% grade. Do all these dead end manholes stink? No. I believe the smell people find objectionable is hydrogen sulfide, which is a gas. Whenever the liquid sewer splashes (like a drop in a manhole), hydrogen sulfide is released. The longer liquid sewer is in the system, the more hydrogen sulfide is produced...so pumping stations with very long times between cycles are usual culprits. Manholes, pumping stations...what do they have in common? They have lids. This magical sludge in the sewer line is 12 feet down, nowhere near any access point.
Let me explain what this story is really about:
Dick: “Residents are complaining about the outfall manhole in Manly Love Estates.”
Jane: “That’s because the pump station is too large for the rate of build out. We should have built two smaller stations, in phases, instead of one big one.”
Dick: “I know, but its too late now, we’ll just have to dose it. It’ll cost $50,000 to install and $10,000 a year.”
Jane: “How do we get THAT past council, without getting the finger pointed back at us?”
Dick: “I have an idea - we’ll blame it on low flow toilets. Most people don’t know anything about sewer, and most people don’t like the low flow toilets. It will be Washington’s fault”
Jane: “Very good idea. Do you think they’ll buy it?”
Dick “Listen, people lose their minds when they hear about low flow toilets. Its a lock!”
I don’t like low flow toilets either; but good grief people! One of the useful natures of a site like this is you can learn the details of an issue, before going off half cocked. This story does not have legs!...and if you try to run with this story in a discussion with a liberal, you will look foolish. Its not something I brag about at high school reunions; but, I design sewers for a living...I thought I’d give some perspective, that’s all.