Household waste flows out of the house via a connecting pipe to the primary chamber of the tank. Organic solid material floats to the surface and forms a layer of what is commonly called "scum." Bacteria in the septic tank biologically convert this material to liquid (effluent.) Inorganic or inert solid materials and the byproducts of bacterial digestion sink to the bottom of the tank and a form a layer commonly known as "sludge."
2. As the primary chamber of the septic tank fills up, this digested material or effluent flows though a connecting pipe to a secondary chamber. This is where the final settling and digestion process in the tank takes place. From the secondary chamber, the effluent passes through an outlet pipe into the leach field for the final purification process. Only clear water (effluent) should exist between the scum and sludge layers. It is this clear water (effluent) and only this clear water that should overflow into the soil absorption area.