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Domestic waste water treatment system

“Traditional” waste water treatment system

Pre-treatment stage

This is the traditional septic tank which does the re-treatment. The solids settle down, the waste water is led directly to the treatment.


Disadvantages: in the septic tank the solids are anaerobically degraded (without oxygen), resulting in an incomplete degradation with production of sludge and highly malodorous gases. The tank must be emptied when the sludge accumulated at the bottom of the septic tank reach half the total capacity of the tank, or every 4 to 10 years following the occupation of the house. The drained sludge must be treated in a wastewater treatment plants.

Sanitation is no longer totally autonomous and cause the concentration of pollution waste water treatment plant.


Treatment with the ground is preferred, either on the soil in place (spreading) or on a reconstituted soil if local soil characteristics are not able to guarantee the treatment and water percolation (sand filters...). In all cases, the system is put underground, not facilitating the monitoring of the system nor its maintenance.


Reed beds


For this phase of pre-treatment, we remove the septic tank in favor of a vertical flow filter planted with reeds. The matters are retained in surface by the filter, while the water percolates through the filter vertically. In this case there is no tank or grease trap.

This type of filter do the primary treatment with filtration, and the secondary (also called aerobic biological treatment) with cultures of microorganisms attached to aggregates.

There is no production of sludge but a compost forms on the surface because of the degradation of organic matter in the presence of oxygen. The compost should be removed approximately every 10 years, used in the ornamental garden. There is no smel.


The vertical filter is constructed in 2 parts, only one side is use each time, there is a weekly alternation.

Plant filter


The treatment is performed in the planted filters which are kind of reconstituted soil in which the plants are installed. Pre-treatment begins in the vertical flow filter under aerobic conditions, then continues in the planted filter.

In the last one, the water flow horizontally by piston effect like a water table, below the surface of the substrate. Therefore there is a mosaic of aerobic and anaerobic zones.

Slow degradation make the finishing treatment of organic matter in solution. It is drained by overflow, therefore it is always filled with water without flushing. Many species are planted there: cattails, yellow iris, purple loosestrife, Simplestem bur-reed, common tule, water mints, water-plantains ... They absorb nitrates and phosphates part of the water for their metabolism.
The plant filter do the secondary treatment, tertiary and quaternary.

The outlet


Output processing, it is necessary to infiltrate the treated water: it is the outlet. This can be done in different ways designed to be integrated with your landscape: pond, ditch, or irrigation channels.

The final phase of infiltration has two tasks in the eventuality of exceptional rainfall or overload pollution, the outlet continue the treatment and helps to improve the effluent quality. The outlet is also planted with semi-aquatic species or if an irrigation plan is chosen, it can be used to water automatically and for free rose’s flowerbed and other ornamental plants. This is the "icing on the cake ': the treated water is reusable and useful in many gardeners use.