Is the cesspit and septic tank the same thing?

Blog Plumbing Tips

Surely you’ve heard of pits and biological pits . But what is the difference between these and the common sewers? Often it is not clear and ends up confusing.

Differences between sewers, cesspool and septic tank
The sewers are a system of interconnected underground canals that are intended to convey black and white wastewater (domestic wastewater and rainwater) to the sewage treatment plants, and free human settlements from hazardous waste. hygiene and health.

Black pit and septic tank instead are alternative systems that are used in the absence of connection to municipal sewers.

Now let’s see in detail how the latter work.

What is the cesspool, how it works, legislation
The cesspit is a septic tank installed to collect manure from isolated houses that cannot connect to the municipal sewer.

The law provides that the owners follow a specific procedure for their installation and that they periodically clean them. To give the authorization to build a cesspit is the municipality of belonging on the basis of a project and a technical report, which includes an analysis by a technical consultant who guarantees the legality of the well itself. Periodically the ASL checks the wells analyzing in particular the compliance of the foams present in the well. Every four years the authorization for the use of the cesspit will have to be renewed by applying to the ASL.

Maintenance of the cesspit
Being simple containers that do not flow into the sewer, cesspools must be periodically emptied and cleaned. To empty a cesspit it is necessary to contact a specialized company of self-cleaning that intervenes with special tanks collecting the waste and disposing of it according to the law.

The sewerage of the cesspit will have a variable cost based on various parameters, such as the size of the well and the conditions in which it is poured, time and personnel used to clean the well, possible extraordinary cleaning interventions. Regular cleaning makes it easier to purge and contain costs, but above all to avoid situations that are harmful to health and the environment.

What is the septic tank and how it works
The septic tank is a type of septic tank which is in fact a static sewer. It is built when the houses are not connected to the sewer system . The septic tank is underground and collects the black water (coming from the wc drains), gray water (washbasins and showers) and other types of waste water, but not rainwater.

The biological pit is composed of a concrete, plastic or fiberglass tank with a trap door for inspection and maintenance. Two tubes are connected to it, one that allows the flow of waste water and one that allows the flow of clarified water. The tank must be positioned more than a meter deep and one away from the foundations of the house or building it serves. The pit must always be external to allow intervention in case of clogging.

Difference between Fosse Imhoff and Fosse Septic
There is a difference between biological Imhoff and traditional septic tanks.

The first is a tank divided into two or three compartments communicating with tubes with deflectors to avoid contamination between the tanks. The solids settle in the first compartment, and the liquids ferment instead, producing methane and carbon dioxide and forming a surface crust. In the other compartments the same process is repeated until the effluents are clarified.

The Imhoff pit instead has an upper compartment for sedimentation and is connected with another compartment for sludge digestion, even if the crust and the gases remain in the underlying part. It is then equipped with an outflow pipe with a bulkhead to prevent the passage of foam which brings the clarified wastewater back into the upper part. The clarified waters have a low septic value and have a higher yield than the traditional pit.