human
Can you explain the differences between a septic tank and a sewage system?
assistant
A septic tank is a small underground chamber that collects and treats wastewater from a building's plumbing system. It typically consists of a container made of concrete, fiberglass or plastic with an outlet pipe leading to a leach field or drainfield. The wastewater flows into the septic tank where it is stored for several days before being released into the ground. The leach field is usually located in a low-lying area away from the house. This allows the wastewater to seep slowly into the soil where bacteria break down the waste into harmless byproducts which are eventually filtered out by groundwater. Sewage systems on the other hand are larger and more complex than septic tanks. They use a network of pipes and pumping stations to transport wastewater to treatment plants. The treated water is then discharged into rivers or lakes.