The autonomous, individual or non-collective treatment of sewage is a business for professionals but also concerns all of us directly and fully. The quality of wastewater discharged from our houses engages our responsibility as users. Faced with legal texts, numerous interlocutors and multiple technical sewage treatment solutions, it is difficult to make an opinion and above all make a choice. This site is therefore designed to explain in a pedagogical way the different sewage treatment solutions (such as septic tanks, micro sewage treatment plants and other solutions), the procedures to respect to achieve legal conformity and inform you how to contact professional specialists.
The water that we use on a daily basis becomes polluted as a result of the way in which we use it.
In fact domestic water discharge is made up of:
- wastewater coming from bathrooms and washing machines containing mainly detergents,
- water from the kitchen containing detergents, oil and fatty materials,
- sanitary water coming from toilets, also known as black water.
Bathroom and kitchen water make up what is known globally as household wastewater.
All wastewater also contains microorganisms which are potentially pathogenic, suspended, organic, nitrogenous and phosphorus matter. These pollutants cause environmental nuisances and sanitary risks. If wastewater is not treated, the environment’s natural purification capacity will be exceeded.
It is therefore necessary to treat pollutants coming from our wastewater in order to conserve the environment, public health, the quality of water resources and our way of life.
The treatment or purification of wastewater by a septic tank or other sewage treatment solutions is designed to limit the quantity of pollutants that contaminate the water in order to discharge water that is respectful to the natural environment.
The Grenelle Law, obliges all buildings to be connected to a sewage treatment system.
Collective, non-collective, individual and autonomous sewage treatment systems?
There are two main types of sewage treatment systems:
Autonomous / standalone sewage treatment systems:
Autonomous sewage treatment systems correspond to all water treatment systems that collect, pre-treat, treat and then discharge domestic wastewater from buildings that are not connected to the public sewer network for wastewater.
There are two types of autonomous sewage treatment systems:
- Non-collective / individual sewage treatment systems: for one dwelling or one building
- Semi-collective / grouped / regrouped sewage treatment systems: for a small group of dwellings.
Individual / Non collective sewage treatment systems:
A non-collective sewage treatment system is a complete water treatment system dimensioned for use with one building (dwelling, tourist site, offices, …)
10% of the French population is concerned by this type of system.
Semi collective / Grouped / Regrouped sewage treatment systems:
A semi collective sewage treatment system is an intermediary solution between the individual sewage treatment system and the collective one. It consists of collecting wastewater via a small network from a small number of buildings (a hamlet, a group of dwellings) and to treat them using a common complete system connected to these buildings.
Collective sewage treatment systems / sewage network:
The sewage treatment system is considered « collective » when the building is connected to a communal sewage evacuation network.
Wastewater is collected by a public sewage collection network (or sewers) and are treated in a collective wastewater treatment system: wastewater treatment station, lagoon, ...
There are two types of collective networks:
- the separative network, which is the most recent, with two different collectors, one for household wastewater and the other for rainwater.
- the unitary network, the oldest system, with only one collector mixing the two types of water.