Municipal public utility in charge of conveying drinking water to the consumer's tap and collecting and treating wastewater and stormwater before returning them to the natural environment. The 30,000 French public water supply and sanitation services are also in charge of the relations with the consumer: information, demand management, billing, etc. The "drinking water supply" service includes the abstraction of water from the natural environment, its potabilization and supply. The "sanitation" service includes the collection, conveyance and treatment of wastewater and the disposal or reuse of sludge…
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Biomass of microorganisms used for treating wastewater from their pollutants (mainly organic matter). Microorganisms are free, suspended in the wastewater, kept inside an aeration tank, and feed on the pollutants. Then, the separation of activated sludge and water occurs in a clarifier: a part of the sludge is put back into the aeration tanks, while the other part (corresponding to the increase of stock) is discharged.
Biological treatment process at fixed culture on carriages. These rotating biological contactors (RBC), generally polystyrene, measure 2 to 3 m in diameter and rotate about a horizontal axis by being partly immersed. Sludges, putrescible very produced by this system are removed by a secondary clarifier.
Process used for the wastewater treatment (by biofiltration) or to eliminate gaseous pollutants dissolved in the water, or to filter surface water in order to make it potable.
System which allows the purification of wastewater by plants mostly reeds: the phytopurification. This method consists in making wastewater flowing through submersed plants, which roots have a high purification power.
Natural purification process, which consists in passing the water through basins, slowly enough to let submersed plants achieving their purification role, before releasing the water in the nature. Indeed, the aquatic vegetation hosts some bacterial communities able to remove pollutants such as nitrates, phosphates...
Aerobic biological wastewater treatment reactor in which the bacterial purifying biomass is placed on an inert support, forming a biofilm (fixed bed). Wastewater is uniformly distributed on the surface and flow downwards with the gravity, through the pores of the filter. Thus, bacteria can degrade the carbon pollution and a part of the nitrogen one. The natural air ventilation carries to the bacteria, all the oxygen they need to eliminate the pollution.