Changes

*[[Practitioner's Tool / Technology and Operation / Septic_Tanks|Septic Tanks]]: A septic system is a small wastewater treatment system designed to treat and dispose of household sanitary waste using a septic tank as the primary component. The septic tank is the first stage in a private wastewater treatment system. Sewage from the building flows to the septic tank where solids are separated from the wastewater flow. The heavier solids sink to the bottom of the tank to form sludge, while the lighter particles, such as hair and grease, rise to the top to form a scum layer.