How does a septic tank work?

A septic tank is part of a septic system that helps get rid of human waste for homes or properties not connected to municipal sewage systems. The function of the septic tank is to collect untreated waste and separate the solids in that waste from the water.

Additionally, the septic tank stores the solid waste so that it can be decomposed as much as possible. Upon separation the initial wastewater is transferred to a drain field. In the drain field the liquids leach, which means to be absorbed, into the soil and return to nature.

In theory the solids retained in the septic tank should have enough natural bacteria to decompose the solid wastes and turn them into a semi-liquid state. When that takes place they dissolve into the wastewater leaving the septic tank and entering the drainage leach field.

For septic tank systems that have few humans making waste deposits there can be periods when the natural decomposition of solid waste does not continue at a rate fast enough to ensure dissipation into the leaching field. In that situation there are probiotic type additives that can help restart the septic tank and over all waste treatment system.

Until the 1960s rural Americans knew that when you built a septic tank and leach field it was necessary to help give the system a kick start. To do that rural Americans knew a good way was to throw a dead chicken or other type of fowl, after removing feathers, into the septic tank. The decomposition of the fowl almost always got the septic system off to a very good start.

What goes into the septic system has a big impact on the rate of decomposition. When people using the system treat their toilets as a trashcan there can be serious problems. For this reason, most septic tanks have a hatch, or opening, made of heavy cement. This can be removed so that a special truck with high volume suction ability can empty the septic tank. This gives the septic system a change to restart handling human waste as it was designed to do in the first place.