Non-collective sanitation - Technical and regulatory developments

In France, non-collective sanitation concerns around 13 million people, and the number of septic tanks in service is estimated at around 5 million. Between 100,000 and 150,000 installations are completed each year, while the total number of installations increases by around 50,000 per year (reference [1] in the [doc. W 6 601] document). The difference between the number of installations and the increase is explained by the removal of old installations, with connection to a sewer network, and by the rehabilitation of pre-existing installations. In the vast majority of cases, a septic tank is used for pre-treatment, and the soil in place, or a substitute filter bed, is used for treatment. Treated effluent is preferably infiltrated on the plot. Where the soil is unsuitable for infiltration, and if health and environmental constraints allow, effluent can also be discharged into the surface water environment, subject to a discharge level.

This document describes the evolution over time of the regulatory and normative context for non-collective sanitation. The following [W 6 602] file presents the hydraulic and biological operating principles of the various pretreatment and treatment techniques, as well as the associated sizing rules.