Saint Sulpice la Foret (Bretagne – France)

Saint Sulpice la Foret : a 1000 PE waste stabilization pond boosted to 1950 PE by addition of reed bed filters. A 2,400 m², vertical flow reed bed (French system), a 1,950 m² second stage vertical flow, unsaturated plus a 10,000 m² of willow plantation and a 5,000 m² pond treating 400 m3/d of domestic effluent.

Additional Info

In operation since: 2010

Type of wastewater treated : Domestic

Hydraulic load: 400 m3/d

Organic load (PE): 1950 PE

Location : Saint Sulpice la Foret, Bretagne – France

Client : Town of Saint Sulpice la Foret

Stage 1 type : Vertical flow reed bed system (French system)

Stage 1 surface area (m²): 2,400

Stage 2 type: pond

Stage 2 surface area (m²): 5,000 m²

Stage 3 type: Vertical flow, unsaturated

Stage 3 surface area (m²): 1,950 m²

Stage 4 type: willow plantation

Stage 4 surface area (m²): 10,000 m²

Cost : 750,000.00 €

Designed by SINBIO



A three series of three waste stabilization ponds was present in Saint Sulpice la Foret. With population development, it was needed to boost the capacity of treatment while remaining on the same site and surface area. The client wished to remain with an extensive treatment system.



Two stage reed bed filters, fed by pumping, with an intermediate pond fed by gravity and infiltration in a willow plantation fed by flow siphon. There is no primary treatment; the raw, only coarse screened sewage is fed directly on the first stage beds with the storage of the filtered dried and mineralized solids for at least 10 years. A stromwater overflow has been created upstream of the pumping station towards the pond in order to allow storage before treatment of stormwater.



Addition of reed bed filter permitted boosting of treatment capacity. Willow plantations are working like Vegetated Polishing Zone with phosphorus adsorption and water infiltration.

Additional Info

  • Hydraulic load: m³/day
  • Organic load (PE): PE
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