On-site sanitation
Septage
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.
Septage 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.
The 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”.
Control 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.
