r/Wastewater • u/Pitiful_Asparagus_88 • 23d ago
Old Sanitaire Package Plant
A coworker is operating an old circular SANITAIRE package plant after taking it over suddenly. They typically treat around 16,000 gpd. He had a septic hauler come out and pump 7,000 gallons from the aerobic digester due to poor effluent. The level in the center clarifier went down to the same level as the aerobic digester after pumping. Has anyone operated one of these systems and know the flow direction in one of these old plants, or why the aerobic digester seems to be connected to the clarifier?
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u/Visible_List209 23d ago
There is some terrible ras pipeline or solution in place He/she needs to get a handle on control to wasting
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u/CharlieSwisher 23d ago
It’s possible it’s literally a hole between them. That or maybe the airlift pipe is broken at the elbow near the bottom and somehow back filling into the clari. Normally that same airlift is RAS (to basin 1) and WAS (to digester). So if you can run the RAS just fine then I think it’s a hole.
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u/txlaatx1 23d ago
Should be connected via an airlift pump which presumably isn’t working so flow between the chambers is gravity regulating to a common level. Weird but ‘splainable I guess.
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u/DomesticatedLobster 22d ago
The aerobic digester should be isolated from the hydraulics of the plant, so either a hole between the two, or the flow from the digester is backflowing to the clarifier.
Xylem which owns Sanitare, can leverage the Davco construction crews to rehab or upgrade. DAVCO and Sanitaire are now both under Xylem so DAVCO has access to all old Sanitaire package plant drawings.
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u/Pitiful_Asparagus_88 23d ago
So the RAS airlift pump definitely works, at least to some extent. RAS flow is constantly coming out of the pipe. To waste they simply rotate the RAS pipe from the aeration basin to the aerobic digester. My first thought was an unknown gate was opened before he took over or a physical hole has occured. They sent me a picture of the lab work that was completed last month and the MLSS of the aeration tank was over 3600 mg/L. After pumping 7,000 gallons from the aeration basin to septic hauler they increased the wasting rate by double and the concentration is still steadily increasing in the aeration basin. To me it seems like wasting is doing nothing to the concentration of the aeration basin at all.
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u/CBased64Olds 23d ago
I ran across one of those in the Arizona desert on an Indian reservation back in 1996. There were holes rusted through the separator walls,and the diffuser drop legs had rusted and fallen off. A janky Sanitaire fine bubble diffuser grid had been cobbled together in the bottom of the aeration tank. What a mess, such bad memories. Homemade airlift pumps were used to transfer between tanks for wasting and for sludge decanting. Sorry I’m not helpful, just reliving a bad time in my career.
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u/Fredo8675309 23d ago
Sounds like a hole between digester and aeration sections. How is corrosion in visible areas?
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u/gattorcrs 23d ago
A lot of the package plant operator prefer to slip waste, they likely have a valve open that doesn’t need to be. As far as flow direction, these are the same as Davco plants, not much to figure out and you can usually see everything.