The septic tank is the gateway to domestic wastewater treatment. It separates liquids from solids and creates the necessary conditions for the process of decomposition of decontamination to begin.
A conventional tank usually has two compartments. The mass of wastewater from your house, called the influent, enters the first tank compartment and its flow slows down so that the heavier solids are deposited at the bottom of the compartment while the lighter ones float to the surface. The solids that accumulate at the bottom of the tank are called sludge, while the lighter solids (grease and fats) that form a mass floating on the surface of the liquid are called scum. Wastewater remains between the sludge and the scum. Microorganisms, including bacteria and other elements, contribute to the natural decomposition of the waste. The sludge and scum are eventually digested, compacting into lower volumes. This is the first step in purifying your home's wastewater.
When the first chamber of the tank is filled, the wastewater begins to flow to the second chamber. The septic tank compartments are designed so that only the liquid (not sludge or foam) can pass from the first chamber to the second chamber. As the influent builds up in the first chamber, and the second chamber is filled, an equal volume of partially treated liquid flows from the first chamber to the second, while an equal volume flows out into the leaching field. The water flowing into the leaching field is called the effluent.
The leaching field is designed to continue the treatment of wastewater. A network of perforated pipes (or clay tiles) in the perimeter of the purification field allows the effluent to be distributed in the natural soil (or backfill). A distribution tank is also sometimes used at the head of the pipes to help spread the effluent more evenly. Holes in the pipes allow the effluent to flow into the soil. The soil then acts as a filter and its microorganisms digest and remove the remaining impurities (such as suspended solids and/or bacteria) from the effluent. Finally, purified water eventually reaches the groundwater tables.
