The Saint-Léger wastewater treatment plant is a fixed biomass plant using biorotor technology PAMCO . It is designed to treat, in the long term, the polluting load of 2,800 p.e. (151.2 kg DB05/d – 336 kg COD/d – 30.8 kg Ntotal/d – 30 kg SS/d – 84 m³/h (3Q18) – 504 m³/d). Currently, the plant is built to treat the pollutant load of 2,200 p.e., which is the pollutant load that the sewerage system currently brings to the plant. The plant is designed to allow for its eventual extension to treat a total load of 2,800 PE.
The treatment process includes:
- A pumping chamber with pebble trap and submerged centrifugal pumps;
- Screening: channel screen press (3 mm mesh) and waste storage container;
- Sand removal: 2 static channels with Sutro gauges to maintain a constant speed;
- A flow limiter – flow distributor ;
- A decanter-digester designed for a storage time of ± 6 months;
- A forced deodorization unit of the decanter-digester on activated carbon drum;
- Two identical biorotors PAMCO identical (+ 1 smaller one of 600 p.e. in the future) of 8.615 m² for carbon removal; the average specific load applied is 5.2 g DB05/m².d;
- An outlet bucket wheel mounted on the biorotor shaft PAMCO in order to read the outlet piezometric line and to regulate the flow to the secondary clarifier;
- A clarifier of 11.85 m diameter with a central drive scraper bridge and radial scraping;
- Two screw pumps placed in the operation building for the purging of excess sludge to the decanter-digester;
- A separate treatment of storm water including a 150 m³ decanter corresponding to about 2.5 hours of storm event and a pump for emptying towards the biological treatment;
- A venturi channel to measure the dry weather flow;
- A low voltage panel installed in the operating building.
