On-site sanitation


On-site installations consist either of a septic tank and soil spreading or of a watertight pit where wastewater is simply stored. The septic tank produces a limited quantity of high-strength septic sludge. The watertight pit produces a more important quantity of lower-strength sludge. The north-eastern area includes both systems and an important number of watertight pits.

Societe collecte les matières de vidangeSeptage collection costs are covered by the individual owner and ensured by an “emptier”, i.e. a company specialised in collection and transportation of wastewater and other sanitation products. A septic tank is emptied approx. every five years by “hydro-cleaners”.

A watertight pit is emptied several times a year. Emptying frequency of both systems depends on pit or tank size and on wastewater volumes.

Septage treatment is mainly ensured by “unloading” into a high-capacity public treatment plant. The Tarn-et-Garonne department currently numbers two equipped plants: the Le Verdier plant of the City of Montauban and SMEAG’s plant in Grisolles. Transport of the septage from the north-eastern area to the Le Verdier plant (more than 50 kilometres for the most distant houses) has a significant impact on costs, fuel consumption and carbon footprint.


plan des 6 reseaux d'ANC du 82The departmental plan for waste disposal divides the territory into six geographic areas each served by a septage treatment unit.

For lack of important treatment plants in the north-eastern area, the Syndicat Mixte Départemental des Déchets-SMDD was authorised to implement a new on-site treatment unit in Nègrepelisse, and entrusted the Communauté de Communes des Terrasses et Vallée de l'Aveyron-CCTVA with its construction. This plant is hereafter referred to as “MV82”.


Logo spancControl of the on-site installations is ensured by the Public Service for Non -Sewered Sanitation -SPANC through an initial diagnostic test of each installation and subsequent regular monitoring. SPANC, a public service utility available to the user, is financed by an annual non-sewered user contribution.

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