"Chuck Harris" wrote in message


This is a common technique used in some septic tanks to give the
drainage field a break. The tank is broken into two chambers. The
first chamber holds the nasty stuff, and overflows into the second
chamber. The second chamber has a pipe that comes up from its
bottom, and performs an upside down "U" bend that goes back to the
bottom (inlet). When the tank fills enough to make the water fall
over the top of the "U" bend, it forms a siphon which draws all of
the water out of the chamber.

In the case of a septic tank, the pipe that forms the "U" bend has to
be sized small enough that a toilet flush will cause it to fill
completely and start the siphon.

So those low-flush toilets that people are forced to use might make their
tanks obsolete.


This is not a problem, because the
second chamber has nothing but water in it. For a municipal sewage
system, the bend would have to be sized based on the usual usual flow
surges that occur in the sewer lines.

-Chuck

Tanks.

(The pun was accidental but I decided to leave it.)

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