Phytopurification in 7 questions

From 15 to 20% of French households use a non-collective sanitation system (ANC). According to the IFAA (French Industries and Companies of Autonomous Sanitation), 60% of the market is intended for new constructions, which favor 90% the approved sectors. Among all the solutions available, there is one newly approved and promised a bright future: phyto-purification, also called planted filter bed.

This 100% ecological treatment solution is now easy to access and makes it possible to combine business with pleasure. To clarify the subject, here are details that will allow you to better orient yourself.

1 - La phyto-purification : What is that ?

Phytopurification is one of the very few 100% ecological and autonomous sanitation systems. With this system delivering quality bathing water at the end of filtration, draining, chemicals and most often electricity consumption are avoided.

The principle of this sanitation is based on the naturally cleansing effect of certain plants. Plants naturally create ecosystems in which bacteria live, which can digest, clean and purify our wastewater. The only condition for taking over the work of these bacteria is not to pour toxic products (solvents, bleach, etc.) into the pipes.
A complete phyto-purification, for an entire family, can be achieved on a surface of only 10m², by playing on the verticality and the horizontality of the filters. The system begins with a pretreatment area often planted with reeds, and ends with two filters planted with different plants, providing a place of life for aerobic bacteria (requiring oxygen) and anaerobic bacteria (not requiring oxygen) .
The cleaned water can be spread by a conventional system or discharged into an artificial pond.

lagoon treatment
Phyto-purification by lagooning for ecological construction (note also the small wind turbine and the solar panel)

2 - Is it an approved system?

Phytopurification systems have been approved for many years, however manufacturers had to receive specific authorizations to market their products.
According to the IFAA, there are around 5 companies approved to manufacture ready-to-install phytopurification solutions. If this figure remains low compared to other approved solutions, it is constantly evolving, because this ecological solution is attracting more and more French people who care about the environment.

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Be aware, however, that it is entirely possible to create your own phyto-purification system yourself, which will still have to be validated by the experts from SPANC (Public Service for Non-Collective Sanitation). To put all the chances on your side, you can entrust the preparation of your file to a BET (Technical Studies Office) specialized in this field.

3 - Who is phyto-purification for?

Contrary to popular belief, phyto-purification is not an individual sanitation solution confined to holiday homes or small areas. Much more sustainable than an additional treatment, phyto-purification makes it possible to treat the wastewater of a family, a hamlet, or even a neighborhood. For example, Caen has a 12,5ha plant treatment area (filtering gardens), which treats between 60m000 and 3m80 of wastewater per day.
For your family home, the required treatment area is much smaller, because it takes around 3m² per PE (Living Equivalent), so a 5-room house (3 bedrooms therefore 5EH) requires a filtration area of ​​around 15m² .

It is also necessary to add the spreading or pond surface to this filtering zone. At similar PE, phyto-purification therefore requires a little more surface area than more conventional solutions.
If phytopurification is suitable for everyone, you must however be able to carry out plant maintenance regularly: pruning, replacement of plants and others. This maintenance is however better perceived by individuals, because it is simply gardening.

4 - How to switch from traditional to phyto-purification?

Many individuals interested in phytopurification have housing already equipped with individual sanitation. This raises the question of the adaptability of this ecological sanitation to a conventional construction.
Again the advantages of phytopurification are numerous, because it can be substituted for an old system without changing its wastewater network or toilets. If dry toilets facilitate water treatment, it is quite possible to keep conventional toilets.
On the other hand, thefuture of your septic tank, if it is in good condition, can be kept and reused as pretreatment. This trick avoids creating an additional zone, generally planted with reeds (upstream of the filters).
The only precaution, which can lead to a change in habits, is not to use toxic products, solvents or strong chemicals.

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5 - How to create a phytopurification system ?

There are two main solutions if you want to create plant filtration.
The first is the simplest: entrust the work to an approved sanitation company. There are brands specializing in plant filtration which, according to the recommendations of SPANC, can create your phytopurification system and save you from digging and planting.
The second solution, which many owners who love nature, prefer to do the work without professional help. In this case, it is always compulsory to follow the SPANC report and warmly recommended to use a BET to carry out the preparatory calculations.

A phytopurification system is generally composed of the following elements:

  •  Pretreatment area (reeds, or old pit).
  • The vertical filter favoring aerobic bacteria.
  • Horizontal filtration favoring anaerobic bacteria.
  • And the median filter (optional) allowing the survival of the two types of bacteria.
  •  Spreading area or pond.

Depending on the configuration of the ground and its slope, it is sometimes necessary to consider the installation of a lifting pump which allows the good flow of water.
There is an excellent community site dedicated to this sanitation technique.

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6 - How much does a phyto-purification cost on average?

The major drawback of phyto-purification remains its higher cost than conventional solutions.
Indeed, for a 5EH installation, it takes from € 9 to € 000, taking into account technical supplies, plants, backfill, but also labor.
In comparison, traditional sanitation varies from € 3 to € 500 and an approved solution varies from € 8 to € 000.

This difference in cost, however, is amortized after ten years, because it avoids the costs of maintenance, emptying and repair. In addition, if the treated water is reused for watering, additional savings are made.

7 - What authorizations to obtain?

Any individual sanitation system is subject to prior authorization from SPANC, which studies the requests on a case-by-case basis. Moreover, this official body most often indicates in its studies, which sanitation system is recommended or imposed. You therefore do not necessarily have the choice of sanitation to install on your land.
On the other hand, by mounting a file supported by technical studies (in particular by a BET), it is possible to tip the SPANC in your favor.
This relative flexibility is explained by the relative novelty of phytopurification systems, which SPANC does not necessarily weaken.

Learn more or if you have a question, visit forum some water

2 comments on “Phyto-purification in 7 questions”

  1. Hello,

    thank you for your forum
    Do you know how to tell me if there are texts which leave the door open to phyto-purification installations without going through one of the rare companies that have had an approval.
    I want to do it in self-construction, possibly going through a specialized design office.
    Pending your return,

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