Technique et gestion de l’assainissement non collectif

Before it was considered an alternative to the collective sanitation system, non-collective sanitation, sometimes still referred to as "autonomous sanitation" or even "individual sanitation", was the general rule.

At the beginning of the 20th century, urban wastewater treatment plants were rare. What's more, domestic wastewater collection was limited to the centers of very large cities. Excreta collection and storage systems ("watertight" pits) were the rule. In the vast majority of cases, these pits were far from watertight. In some cases, a hole was drilled at the bottom of the tank to allow the liquid part of the excreta to escape, thus reducing the frequency of emptying, which was always costly.

Because of its low population density and housing structure, France will always have a high proportion of its population connected to on-site sewage systems, whether single-family or grouped.

Ensuring the quality of sanitation practices is therefore essential.

So, in a series of three articles, we're going to take a look at the history of the regulations, and then present the state of the art in terms of the various techniques that can be used, including some that can only be used with a waiver from the prefectural or municipal authorities.

Next, we'll take a look at the missions of a Service public d'assainissement non collectif (SPANC). We'll describe the various control procedures that need to be put in place for the design, construction and maintenance of ANC systems, and for the management of septage.

In this first article, after a brief history and review of the legislation and regulations governing non collective sanitation, we look at wastewater pre-treatment and lifting techniques.

Note: at the end of the article, readers will find a glossary of important terms and expressions, as well as a table of acronyms, notations and symbols used throughout the article.