Its sanitation system

The sanitation system

The wastewater is collected near La Coujoune by a mainly gravity sewer network, then pumped to Courounets through a 2-km long pressure pipe, treated in the WTP and discharged into the Courounets creek through its tributary, the Montrosies creek.

Collection

The network is composed of 20 km of gravity pipelines, seven pumping units and 5 km of pressure pipes.

At the end of 2009, it served 1069 customers or approx. 2500 users or 76 % of the customers to the drinking water network.

 

 

 

Nègrepelisse’s
sewered network

Treatment

In 1982, the City implemented in the Courounets area a first WTP comprising two ponds with a treatment capacity of 1400 PE. In 2003, CCTVA was put in charge of the plant, identified its limited capacity and undertook to replace it with a constructed wetland system with an initial capacity of 4000 PE to be extended to 6000 EH as foreseen by the sewer network planned for 2020 and extensible ensuite à 6000 EH, correspondant aux prévisions de raccordement au réseau en 2020 et 2050, respectivement.

Combiné de filtres et lagunes

Constructed wetlands were still rare in 2004 and  used only for small capacities. A visionary mind was needed to extend to 6000 PE a process applied only occasionally and never above 2000 PE.

CCTVA adopted this course right from the beginning and decided, with the advice of SATESE 82, to keep the existing ponds and integrate them in the treatment process.

Consequently, upon operation of the new components in 2009, Nègrepelisse’s WTP became the most important constructed wetland system in France and one of the very first to combine filters and ponds.