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The septic tank. Septic tanks
are large, underground watertight containers, typically about 9 feet long,
4-5 feet wide and 5 feet tall that is connected to the home’s sewer line.
While typically designed with a 1,000-gallon liquid capacity, the size of the
tank is legally determined by the number of bedrooms in the home. Septic
tanks may be rectangular or cylindrical and may be made of concrete,
fiberglass or polyethylene.
Raw waste water from the bathroom, kitchen and laundry room flows into the
tank where the solids separate from the liquid. Light solids, such as soap
suds and fat, float to the top and form a scum layer. This layer remains on
top and gradually thickens until you have the tank cleaned. The liquid waste
goes into the drainfield, while the heavier solids settle to the bottom of
the septic tank where they are gradually decomposed by bacteria. But some
non-decomposed solids remain, forming a sludge layer that eventually must be
pumped out of all septic tanks.
Septic tanks may have one or two compartments. Two-compartment tanks do a
better job of settling solids and are required in some areas for new
installations. Tees or baffles at the tank’s inlet pipe slow the incoming
wastes and reduce disturbance of the settled sludge. A tee or baffle at the
outlet keeps the solids or scum in the tank. All tanks should have accessible
covers for checking the condition of the baffles and for pumping both
compartments. |
