Umpisäiliöt

Umpisäiliöt, commonly known as septic tanks, are underground wastewater treatment structures. They are primarily used in areas without access to municipal sewer systems. The tank's main function is to collect and partially treat sewage from a building. Inside the tank, solid waste settles to the bottom, forming a sludge layer, while lighter materials like grease and oils float to the top as scum. The liquid wastewater, called effluent, remains in the middle layer.

The treatment process within the septic tank relies on anaerobic bacteria, which break down some of the organic matter in the sewage. Over time, the sludge and scum accumulate and require periodic removal through pumping by a professional service. The treated effluent then typically flows out of the tank into a drainfield, also known as a leach field. This drainfield consists of underground trenches or a bed of gravel or chambers, where the effluent is dispersed and further purified by soil and microorganisms before it can seep into the groundwater. Regular maintenance, including pumping, is crucial for the longevity and effective functioning of both the septic tank and the drainfield, preventing system failures and environmental contamination.