Recirculated vertical flow French system for 800 p.e. with polishing in a "natural" horizontal flow wetland
Municipality « ST THIBAUD DE COUZ» Savoie (73)
Wastewater treatment plant for 800 p.e., domestic sewage, separative sewerage system, constructed in 2003
Designed by SINT/SINBIO
“French sytem” treating raw unsettled sewage in a vertical flow reed recirulating filter (3 * 323 m²), followed by a horizontal flow filter using onsite turf soil (3194 m2).
The town of St. Thibauld de Couz, in the Savoie Region, had to construct its new wastewater treatment plant in an old marshland with turf soils
The most stable part of the terrain was transformed into a recirculating French vertical flow filter, fed directly by a pumping station. The remaining area was just terrassed and the local turf soil used for a tertiairy horizontal filtration in order to achieve a very high level of treatment before discharging into the Lake Bourget catchment
The use of local turf soil for tertiary treatment without any plastic lining proved to be a very cost efficient solution to polish the water before discharge. In summer, there is zero suface water discharge. The vertical flow recirculating filters have been monitored scientifically :
Prost-Boucle S.. Molle P. (2010). Recirculation on a single stage of vertical flow constructed wetland: treatment limits and operation modes. Ecological Engineering 43 (2012) 81– 84
