Constructed wetlands for wastewater treatment: the French experience

Concerning wastewater treatment, France has a very special position in Europe: the 60 millions inhabitants, according to the census of 1999, are spread over 36 600 administrative districts. France has compared with the the neighbour countries, a low population densisty (100 inhabitants per km²). Even though an important part of the population is living in some important urban areas, 25% of the population is spread over 31 900 administrative districts of less than 2 000 inhabitants. This situtation explain s the importance part of on-site treatment (11 millions inhabitants, 5 million plants) and the high number of low capacity treatment plant have a capacity lower then 2 000 Person Equivalent (PE). Above 1000PE, the treatment process is mainly based on activated sludge. Below, more rustic processess are being used: Waste Stabilisation Ponds (WSP), Intermittent Sand Filters (ISF), and Reed Bed Filters (RBF). "Rustic" and rather simple wastewater treatment systems for such small communities in rural areas have been a major interest of Cemagref for a long time.