Septic Systems


An excerpt from The New York Times print archive.

Article written in 1984, by Bernard Gladstone

"ALTHOUGH most urban homes and many suburban homes have long since been connected up to a municipal sewage disposal system, there are still a great many suburban and rural homeowners who will have to depend on their own private sewage disposal systems for many years to come - usually a septic tank that is connected to a drainage field or seepage pit of some kind. A well-designed system will last almost indefinitely if properly maintained, but if it is neglected for too long a time, it can back up and clog the drainage field, calling for an expensive excavation and replacement of drain pipes that could cost thousands of dollars.

Although designs vary, most septic tanks are basically similar to the one shown in the drawing. They consist of a watertight, below- ground precast concrete tank that has one or two manhole covers (buried a few inches below ground) to provide access for cleaning and inspection. Effluent from the house flows into the tank through an inlet pipe near the top on one side, as shown, while it flows out through a discharge or overflow pipe at the other side.

As can be seen in the drawing, each of these pipes ends in a large tee-fitting so that effluent cannot flow straight across from one pipe to the other. Incoming effluent will be diverted downward with a minimum of splashing so that solids sink to the bottom. Outgoing effluent is drawn from several feet below the top layer of floating waste (scum) so that only liquid waste - or solids that have been liquefied by the bacterial action that goes on at the bottom of the septic tank - are discharged out into the drainage field."   


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