Economical

The implementation cost of a CW wastewater treatment plant is generally lower than that of an intensive plant up to 2000 PE, similar between 2000 PE and 5000 PE.

The running cost of a CW wastewater treatment plant is generally two or three times lower than that of an intensive plant for an identical outlet quality, in the normal application range of CW of course (to 6000 PE currently, in the absence of a severe limitation on nitrogen and/or phosphorus outlet content).

A CW plant takes more space than that an intensive plant, up to 5 m²/PE above 2000 PE, and even more for less than 2000 PE.
In Nègrepelisse, the initial 4000 PE plant is contained on a plot of 16 380 m² or 4.1 m²/PE including circulation along the creek and land reservations for the extension to 6000 PE. The works as such are contained on less than 12 000 m² i.e. 3 m²/PE with large circulation and parking expanses.
The 6000 PE configuration will use 24 000 m² i.e. 4.0 m²/PE including the circulation along the creek and unused areas.

In the septage treatment field, the implementation costs are quite similar between CW or intensive techniques but the CW running costs are much lower.