EP4007741A1

EP4007741A1 - Waste water treatment plant

Info

Publication number: EP4007741A1
Application number: EP20739715.9A
Authority: EP
Inventors: Martin WERCKMANN; Elodie MAILLARD
Original assignee: Aquatiris
Current assignee: Aquatiris
Priority date: 2019-08-01
Filing date: 2020-07-16
Publication date: 2022-06-08
Also published as: FR3099473B1; WO2021018629A1; FR3099473A1

Abstract

Disclosed is a waste water treatment plant comprising: - means for introducing the waste water; - a pre-filter device transforming the waste water into pre-treated water that comprises a pre-treatment vessel containing lignocellulosic compounds and microorganisms; - discharging means for discharging the pre-treated water; - at least one planted filter device transforming the pre-treated water into treated water, arranged in series and positioned downstream of the pre-filter device and supplied with pre-treated water by the discharging means, - the planted filter device comprising distribution means supplied by these discharging means, and a filter bed constituting a culture medium for semi-aquatic plant species, - the filter bed comprises at least three layers of minerals including a filtering layer, a transition layer, and a draining layer; - means for draining the treated water, on which the draining layer opens, configured to drain the treated water out of the planted filter device.

Description

Title of the invention: Sewage treatment works

[0001] The present invention falls within the field of water purification.

It relates more particularly to a wastewater treatment structure and the implementation of a wastewater treatment process.

[0002] The invention relates to a sanitation structure advantageously provided for non-collective sanitation, that is to say for individual dwellings, in particular for individuals.

[0003] Whether for collective buildings, such as residential or professional buildings, or whether for individual buildings, such as single-family homes, wastewater treatment is a recurring health issue.

[0004] In general, the waste water comprises a mixture of organic and inorganic compounds in dissolved form and in solid form.

In the present, the term “wastewater” is understood to mean the raw water leaving directly from the collective or individual building. “Wastewater” is made up of “gray water”, and “black water” coming out of the toilets. “Wastewater” comprises a mixture of compounds in solid form and compounds in dissolved form in liquid medium.

Likewise, the term “pretreated water” is understood to mean wastewater which has undergone pretreatment. The purpose of this pretreatment is to remove coarse solids in flotation, suspension, sands and excess grease and oil. "Pretreated water" is generally obtained either by screening the effluents, that is to say by eliminating, by passing through a screen, the larger materials contained in the waste water, or by phase separation, that is to say by settling of the solid compounds and flotation of oils and fats then liquefaction.

[0007] In the present application, the term "water

treated ”, pre-treated water which has been sanitized. The “treated water” is sanitized, so that it can be discharged into nature without risking polluting aquatic environments, in particular the water table. Within the meaning of the invention, “treated water” is sanitized, with a concentration of pollutants admissible for their discharge directly into nature. Depending on the pre-treatment and treatment device used, it is even possible that the "treated water" can be reused, that is to say return to a collective or individual housing network, for example to supply a hunting. toilet water.

[0008] Several known sanitation devices make it possible to treat "wastewater" to transform it into purified "treated water".

[0009] As is known for sanitation and wastewater treatment, there are different channels with different devices such as

micro-treatment plants, existing soil treatment devices such as spreading trenches, reconstituted soil treatment devices such as sand filters, compact filters, or planted filter devices.

[0010] The micro-treatment plants ensure both the pre-treatment of wastewater in an all-water tank, then its treatment in different

compartments. Small wastewater treatment plants consist of a first pre-treatment compartment ensuring the separation of solid and liquid compounds contained in the wastewater. This first compartment acts as an all-water tank. At the outlet of this first compartment, there is a liquid effluent. The liquid effluent is suitable for undergoing treatment in a second tank or compartment called a "biological reactor". Within the biological reactor, thanks to the bacterial growth in an aerobic and / or anaerobic medium, the liquid effluent is degraded and depolluted so as to obtain "treated water". The latter can be rejected in nature. In VSATs, the first compartment stores the sludge produced during the second phase of treatment.

[0011] VSATs have several disadvantages.

[0012] Indeed, the degradation sludge produced and accumulated in the all-water tank is odorous because of its fermentable nature. In addition, it is necessary to remove them regularly by performing a maintenance drain, generally every 6 months to 4 years. In general, it is mandatory eliminate degradation sludge as soon as 30% of the storage volume of the first tank is reached. In addition, a regular supply of wastewater to the VSAT is necessary so that the bacteria have a regular supply of nutrients necessary for their growth, this growth being essential for the treatment of wastewater. A long lack of wastewater supply affects the operation of the VSAT. Thus, if the inhabitants of a building are absent for whatever reason, the small wastewater treatment plant may malfunction due to a lack of supply. The

maintenance and upkeep of a VSAT is time consuming and expensive.

[0013] To clean up wastewater, for example from individual dwellings, it is also known practice to use sand filters or spreading trenches, after pretreatment of the wastewater in an all-water tank. To sanitize with a sand filter or with spreading trenches, it is first necessary to pre-treat the wastewater in an all-water tank. The latter collects and retains the wastewater, then liquefies the solids to allow their subsequent treatment in the sand filter or the spreading trenches, while accumulating the non-liquefied solids, such as settling sludge, and the solids floating, fat type.

[0014] At the outlet of the all-water tank, the pretreated water is conducted to the sand filter for treatment. The water is purified using the micro

organisms growing in the sand filter. The latter consists of a layer of gravel, in which the spreading pipes are inserted to ensure the distribution of the pretreated water, and consists of a filter bed made up of sand, the site of the purification processes. However, the use of a sand filter buried in the ground as a means of filtration to treat water generates a risk of clogging of the filter which then loses its operating efficiency over time. As the sand filter is directly buried in the soil, the lack of oxygen and the addition of organic matter in the sand causes clogging.

In the same way, at the outlet of the all-water tank, the pretreated water can be conducted towards the spreading trenches. The pretreated water is purified by physical filtration of the soil and the action of soil microorganisms. To have a functional spreading trench, several criteria must be met. For example, it is essential:

- that the available surface for deployment of the trenches is at least 20 to 30 m ² / pe, expressed in square meters per Equivalent Inhabitants known as “PE”,

- that the trenches have a depth of 50 cm to 1 m and that the soil has physico-chemical characteristics allowing the growth of micro

purification organisms, good oxygenation and high permeability, in order to avoid the risk of the treated water rising,

- that the depth of the water table is greater than 1.40 m,

- or that the ground has a slope of less than 5% of height difference.

[0016] All these conditions prevent many collective or non-collective buildings from setting up a system of spreading trenches to treat their wastewater.

It should be noted that the unit of measurement of m ² / pe corresponds to the floor area necessary for the treatment device to treat polluted water, generated by a person living in a habitat, and transform it into water processed.

[0018] Whether for sand filters or spreading trenches,

the accumulation of odorous fermentable sludge in the all-water tank is systematic. Thus, in addition to seeking to eliminate the release of odorous fermentation gases, emptying the sludge is frequently necessary. In addition, sufficient deployment space on the ground, to install sand filters or spreading trenches is necessary to treat wastewater.

As an alternative to sand filters or to spreading trenches, it is also known to use compact filters at the outlet and in addition to an all-water tank for the treatment of water.

[0020] The compact filters mainly operate in an aerobic environment. We

By compact filters means devices arranged at the outlet of an all-water tank and made up of a filtration unit which may be composed of a wide variety of materials, organic, inorganic or synthetic, such as zeolite filters, coconut filters, wool filters. rock... [0021] Compact filters require an all-water inlet tank for the pre-treatment and settling. However, the all-water tank gives off foul odors due to the production of fermentation gas by the sludge that must be eliminated. This sludge must also be emptied regularly.

[0022] Thus, the maintenance of compact filters is expensive and time-consuming.

[0023] In addition, compact filters, in particular those comprising a material

inorganic or synthetic, require a change and renewal of the filter material which is expensive. The used inorganic or synthetic materials, removed during the maintenance of compact filters, also pose problems in terms of management and from an ecological point of view since they are not biodegradable and not recoverable.

Unlike treatment devices by the soil or by a soil

reconstituted, with compact filters or even in VSATs, vertical flow planted filters are capable of carrying out both pre-treatment and wastewater treatment. The technology of planted filters no longer requires the association with an all-water tank. Likewise, planted filter technology does not require, like VSATs, the presence of a first integrated compartment playing the role of an all-water tank.

[0025] The technology of planted filters with vertical flow is based on the filtration of wastewater through a filter bed.

In general, to clean up a collective dwelling, a coarse screening of the wastewater is necessary, this before the filtration step by the technology of planted filters with vertical flow through the filter bed. The filter bed is made up of inorganic aggregates, of different grain sizes, in which plants, especially reeds, grow. The development of a dense network of rhizomes and plant roots makes it possible to provide the filter bed with an excellent support for the biomass participating in the purification process. These plants, in particular the reeds, also play an indirect mechanical role in the mineralization of the sludge, and promote the percolation of the interstitial water by unclogging the surface of the filter bed. The pore water will be drained along the roots towards the base of the massive. The suspended solids are retained on the surface and gradually accumulate. Filtration of these solids by

suspension is ensured by the installation of materials of suitable particle size to retain organic and inorganic matter.

[0027] There are two types of filters planted with reeds: filters planted with

vertical flow and planted filters with horizontal flow. Planted filter technology is based on aerobic biological purification in fine granular media.

Whether for vertical or horizontal flow filters, the footprint is generally substantial, between 1, 5 and 4 m ² per PE depending on the characteristics and arrangements of the filters. For planted filters with horizontal flow, a water supply beforehand

cleared of their suspended matter is necessary to prevent clogging of the filter bed. This can be done through an all-water tank, a first stage of a vertical planted filter, or a digester settling tank placed upstream.

As for the planted filters with vertical flow, they are generally

consist of one or two floors. Each stage comprising at least two filtering units arranged in parallel, the latter operating alternately at the level of the same stage. One or the other of the first stage filter beds is fed by tarpaulins. Thus, the wastewater arrives alternately on one or the other of the filter mass of the ^1st stage, so that the effluent percolates vertically through the substrate of the filter mass of the ^1st stage. Depending on the physicochemical characteristics of the filtering mass of the first stage such as the thickness and the particle size, the effluent at the outlet corresponds either to pre-treated water or to treated water.

[0030] If the effluent leaving the filter block of the first stage corresponds to treated water, a second stage is not necessary, and the treated water can be directly discharged into the natural environment.

If the effluent at the outlet of the filter block of the first stage corresponds to pretreated water, a second treatment stage is necessary. This second floor also comprises at least two filtering masses arranged in parallel which are supplied alternately by tarpaulin.

[0032] In vertical flow planted filter systems, the rest or alternation phases are essential for the proper functioning of the system, its reliability and its durability over time. In fact, the alternation of supply to the filter blocks arranged in parallel makes it possible to put the filter blocks at rest for periods generally varying from 3 days to 1 week. The rest period of a filter bed thus allows the accumulated suspended matter to dry and to mineralize, therefore to drastically reduce in volume.

However, the planted filters with vertical flow being directly fed by raw wastewater without prior pretreatment; so

disadvantageously, the accumulation of suspended matter tends to clog the surface of the filter bed if it is still in water. In addition, the permanently suspended matter in water generates odors

foul-smelling disadvantageous.

[0034] Thus, it is considered that the rate of accumulation of suspended matter on a vertical flow filter is of the order of 1 cm / year.

[0035] Cleaning is therefore essential to sustain the operation of the

system. This is recommended every 10 to 15 years on average.

[0036] In addition, as the rest phases are essential for the operation of the planted filters, it is necessary to have at least two independent filter beds per stage. Consequently, sufficient floor space for deployment, as well as a device for directing the water into one or the other of the filter beds, is essential with the vertical flow planted filters of the prior art.

[0037] Document FR 2 975 390 discloses an example of a device for purifying domestic wastewater using the technology of filters planted at

vertical flow which have the aforementioned disadvantages. This document discloses a device for purifying domestic wastewater comprising a means for supplying domestic wastewater leading to an inclined supply ramp, which cooperates, at a ^1st floor, with at least a 1st planted vertical flow filter. The latter leads to a tipping bucket system which surmounts a tank. This tank feeds, at a ^2nd stage, at least one ^2nd filter planted vertical flow. This ^2nd filter planted vertical flow leads to additional purification means at a 3 ^rd. These means of purification

Additional can consist of a planted filter with horizontal flow.

[0038] Document FR 2 975 390 specifies that:

- the inclined feed ramp is provided with rollers in the bottom so as to allow a coarse screening of wastewater, as well as aeration and disintegration of suspended solids to form solid particles of smaller size ;

[0040] - with the tipping bucket system, the effluent undergoes anaerobic treatment favored by stagnant ferments in the bucket, lasting from 5 min to 24 hours. During purification, a residual volume of effluent remains permanently contained in the trough;

- The 1 ^st and 2 ^nd planted vertical flow filters allow aerobic biological treatment;

[0042] -the additional purification means allows the realization of the last

anaerobic treatment to end up obtaining treated water;

A plurality of 1 ^st planted filters with vertical flow and a plurality of 2 ^knots planted filters with vertical flow, with an alternating supply is a preferred embodiment;

[0044] Thus, the device for purifying domestic wastewater, from FR 2 975 390, has several disadvantages.

The deployment surface on the ground is substantial. Indeed, the filter ¹ has planted 1, 25 m in diameter at the top, the ^2nd filter planted 1 m in diameter, the bucket may contain up to 80L, this excluding the space occupied by the ramp 'feed, supply lines and additional purification means.

[0046] In addition, the device of document FR 2 975 390 is complex due to the

multitude and variety of elements that compose it. We have ramps, a bucket tipping system, and stages with one or more planted filters with vertical flow supplied alternately, but also at least one planted filter with horizontal flow or a basin or a pond or a lagoon. The management of each of these elements having different maintenance needs is therefore complex.

[0047] In addition, the feed ramp and the trough being uncovered, the release of foul odors, due to the treatment of the water and to the fermentation by microorganisms, is disadvantageous.

[0048] In addition, with the device described, the risk of clogging of each of the

filter media persists, especially in the case of a continuous water supply. The cleaning of the sludge stagnant on the surface of the filter beds is undoubtedly necessary, and the untreated residues of solid matter are not easily recoverable in the bucket for recycling.

In addition, in the privileged case of a plurality of 1 ^st and 2 ^nd filters planted at

vertical flow, the alternating feed must be controlled to respect the standing times of the beds and avoid their clogging.

[0050] Even if it is satisfactory for transforming domestic wastewater into treated water which can be discharged into nature, the device of document FR 2 975 390 has major drawbacks in terms of odor nuisance

potential, land use, operation and management of solid residues from wastewater treatment. The device of document FR 2 975 390 is complicated and difficult to install, manage during processing and maintain. It generates foul odors, while

encumbering the land in unattractive ways due to the multiplicity of treatment structures.

[0051] Thus, the solutions of the prior art, making it possible to treat wastewater, pose several problems or constraints:

- the need to first have an all-water tank or at least coarse screening of wastewater, before being able to undergo pretreatment or treatment,

- the need to have a significant ground deployment in terms of surface area, - the need to have a soil exhibiting particular physicochemical characteristics, in particular in terms of the nature of the soil, difference in level, surface covered, depth and distance from the surface of the water table,

- the need for regular cleaning of the stagnation sludge for proper operation and maintenance, in order to avoid clogging of the filter and bad odors,

- the need to alternate the treatment phases with resting phases to prevent clogging of the filter in the case of planted filters or, on the contrary, to have a regular and continuous supply of wastewater to prevent clogging of the filter and to maintain sufficient biomass, for example in the case of a VSAT.

All these technical obligations and constraints do not make it possible to find a universal and effective solution for treating wastewater and transforming it into treated water easily, regardless of the nature of the land, without maintenance or maintenance. is mandatory, and regardless of the nature of the wastewater or its solids concentration.

This is why an alternative solution should be found, to existing wastewater treatment solutions, which is efficient, and applicable to a maximum of individual or collective buildings.

The object of the present invention is to overcome the drawbacks of the state of the art, by providing a wastewater treatment structure.

[0055] Thus, said wastewater treatment structure of the invention

comprises:

- means of introducing wastewater,

- a pre-filter device on inert lignocellulosic material, this pre-filter device, on the one hand, is configured to transform waste water into pre-treated water and, on the other hand, comprises a sealed and closed pre-treatment tank, which is supplied with wastewater by the means of introducing wastewater, and which internalizes calibrated lignocellulosic compounds and aerobic microorganisms, - means of evacuating the pre-treated water which are configured to evacuate the pre-treated water outside the pre-filter device,

- at least one planted filter device with vertical flow, which is configured to transform the pre-treated water into treated water, which is arranged in series and positioned downstream of said pre-filter device, which is supplied with pre-treated water by the discharge means pre-treated water,

- said planted vertical flow filter device comprises, on the one hand, means for distributing the pretreated water, which are positioned in the

extension of said pretreated water evacuation means and which are fed by these pretreated water evacuation means, and, on the other hand, a filtering mass, which is surmounted by the pretreated water distribution means, and which constitutes a culture medium for semi-aquatic plant species,

- Said filter bed comprises at least three layers of minerals including a filter layer which is located in the upper part of the filter bed, a transition layer which is surmounted by the filter layer, and a draining layer which is surmounted by the transition layer and which is located in the lower part of the filter bed,

means for draining the treated water, onto which the draining layer opens, and which are configured to drain the treated water outside said at least one planted filter device with vertical flow.

[0056] In addition, according to other features of the invention, the work

sanitation includes:

- the filter layer consists of a layer of sand with a grain size between 0 and 6 mm,

- the transition layer consists of a layer of gravel with a particle size between 2 and 10 mm,

- the draining layer consists of a layer of coarse gravel with a grain size between 10 and 40 mm.

[0057] More specifically, the work of the invention comprises:

- the filter layer has a thickness between 20 and 50 cm,

- the transition layer has a thickness of between 5 and 15 cm, - the draining layer has a thickness between 10 and 20 cm thick.

[0058] According to a preferred embodiment of the invention, that the filter layer and / or the transition layer and / or the draining layer consists (s) of predominantly siliceous, non-calcareous, washed and rolled mineral materials.

[0059] According to another embodiment of the sanitation work of

the invention, said filter bed comprises, above said filter layer, a sanitary protection layer at least partially covering said means for distributing the pretreated water.

Advantageously, said means for introducing wastewater consist of a pipe, the outlet end of which, supplying the pre-treatment tank, is positioned above the upper surface of the lignocellulosic compounds at a height distance of between 30 and 60 cm.

According to a preferred embodiment of the sanitation structure of the invention, said means for introducing waste water and / or said means for removing pre-treated water include a lifting pump or a flushing structure. .

[0062] According to the invention another characteristic of the invention, the compounds

Lignocellulosics in the pre-treatment tank are in the form of an assembly of calibrated wood chips, between 30 and 60 cm thick.

[0063] According to another embodiment of the invention, said means of

distribution of the pretreated water consist of a distribution ramp, preferably an H-shaped or I-shaped or U-shaped drain, placed directly on the filter layer.

Advantageously, to improve the wastewater treatment process, according to another particular characteristic of the invention, said pretreatment tank, internalizing lignocellulosic compounds and aerobic microorganisms, further comprises earthworms. The present invention also relates to a method for sanitizing wastewater implemented by the sanitation structure 1 of the invention in which:

- the said pre-treatment tank is supplied directly with wastewater using the means of introduction,

- the suspended matter of the wastewater is filtered and mineralized within said pre-treatment tank until pre-treated water is obtained at the bottom of the pre-treatment tank,

- at the bottom of said pretreatment tank, said pretreated water is recovered in discharge means,

- said pretreated water is transferred directly to the filter bed of the planted vertical flow filter device using the evacuation means,

- said pretreated water is treated by passing through said filtering block until the treated water is obtained,

- said treated water is drained outside the filter bed and the planted filter device with vertical flow,

- said treated water is directed to the natural environment or to a domestic water recycling network.

[0066] The present invention also relates to the use of the work

wastewater treatment plant of the invention as a water purifier.

Other characteristics and advantages of the invention will emerge from the

detailed description which will follow of non-limiting embodiments of the invention, with reference to the appended figures, in which:

[0068] [Fig.1] Figure 1 schematically shows a sectional side view of the wastewater treatment structure according to a preferred embodiment of the invention.

[0069] [Fig.2] Figure 2 schematically shows a sectional side view of the prefilter device on lignocellulosic material according to the embodiment of Figure 1,

[0070] [Fig 3] Figure 3 shows schematically a top view of the

pre-filter device on lignocellulosic material of Figure 2, [0071] [Fig 4] Figure 4 shows schematically a sectional side view of the planted filter device with vertical flow of Figure 1,

[0072] [Fig 5] Figure 5 shows schematically a top view of the

vertical flow planted filter device of Figure 5.

With reference to these drawings, the present invention relates to a work

wastewater treatment 1 EU, as visible for example in Figure 1. Said sanitation structure 1 is advantageously buried in the ground, at least in part, to maintain an aesthetic appearance.

[0074] According to a first embodiment, said sanitation structure 1

comprises a pre-filter device 2 on inert lignocellulosic material 22 positioned upstream of at least one planted filter device with vertical flow 3.

According to another embodiment, visible in Figure 1, said structure

of sanitation 1 consists of a pre-filter device 2 on inert lignocellulosic material 22 positioned upstream of a planted filter device with vertical flow 3.

[0076] According to the invention, said pre-filter device 2 on inert lignocellulosic material 22 is configured to transform EU wastewater into EP pretreated water.

Likewise, said at least one planted vertical flow filter device 3 is configured to transform the EP pretreated water into ET treated water.

According to the invention, the pre-filter device 2 and, the planted filter device (s) with vertical flow 3, are arranged in series, one after the other, and are all preferably buried in the ground.

In other words, said at least one planted vertical flow filter device 3 is arranged in series with said prefilter device 2 on material

lignocellulosic 22 inert. Said at least one filter device planted at

vertical flow 3 is also positioned downstream of said prefilter device 2 on inert lignocellulosic material 22, as can be seen in FIG. 1.

[0080] Depending on the topographical characteristics of the land, such as the

difference in level, said pre-filter device 2 is supplied with EU wastewater: - either by gravity in the case of sloping land with a slope of at least 2 to 3%;

- Or by a lifting means, such as, for example, a lifting pump.

As seen in Figure 2, said prefilter device 2 on material

Inert lignocellulosic 22 comprises means 4 for introducing EU wastewater.

Said introduction means 4 feed EU wastewater to said prefilter device 2 on inert lignocellulosic material 22.

Said introduction means 4 are configured to inject the waste water EU, over the water when the feed is gravity or at constant volume and by controlling the flow when the feed is performed by means of a lifting pump, in a pre-treatment tank 21.

The means of introduction 4 consist for example of a pipe

entrance connected to the EU wastewater network of a collective or individual dwelling.

[0085] According to a particular embodiment, the introduction means 4 can also be provided with "jet breaker" devices and anti-scour plates making it possible to guarantee the good distribution of the EU wastewater on the inert lignocellulosic material 22.

[0086] According to another particular embodiment, the means 4 for introducing EU wastewater comprise a lifting pump or a flushing structure.

Advantageously, said pre-treatment tank 21 is sealed and closed, so as to avoid the emanation of foul odors.

Advantageously, said pre-treatment tank 21 is buried in the ground, so as to keep the aesthetics of the land and so that it is not visible to users.

As shown in Figure 2, the pretreatment tank 21 comprises one or more opening means 23, of the unscrewed cover type. These opening means 23 allow an operator to access the interior of the tank 21 if necessary. These opening means 23 are accessible at the surface of the ground. For example, the opening means 23 allow an operator to remove all or part of the inert lignocellulosic material 22 contained inside the tank 21, to revalue them as compost.

[0091] According to the invention, said pretreatment tank 21 is filled with material

lignocellulosic 22 inert. In other words, said material is non-living. According to the invention, the term "inert lignocellulosic material" is understood to mean a material which comprises liqnocellulosic compounds devoid of specific activity and which are inherently dead.

More specifically, said inert lignocellulosic material 22 comprises calibrated non-living lignocellulosic compounds. By the term

"Calibrated non-living lignocellulosic compounds" of the compounds which are transformed and machined. Preferably, the calibrated non-living lignocellulosic compounds consist of an assembly or clusters of calibrated residues of wood such as platelets. The wood, although coming from a living organism, once in the form of a "plate" that is to say when the tree is dead and cut, is part of the calibrated non-living lignocellulosic compounds within the meaning of 'invention.

[0093] Preferably, the cluster of inert lignocellulosic material 22 has a thickness of between 30 and 60 cm. According to the invention, the size of each of the wood chips is between 20 and 100 mm long maximum, beyond the filtration of the water is not efficient.

Thus, the pre-treatment tank 21 containing a mixture of several

Wood chips, in the form of 2-10 cm chips, is an ideal aerated medium for the growth of aerobic microorganisms. These allow in particular the mineralization of solids contained in EU wastewater and the composting process.

[0095] The use of wood chips as a lignocellulosic material 22

inert has the advantage of being eco-responsible because wood is a 100% biodegradable and renewable compound.

In addition to the calibrated non-living lignocellulosic compounds 22, the pretreatment tank 21 comprises and internalizes aerobic microorganisms. These the latter have a growth which takes place in an aerobic environment, that is to say in the presence of oxygen.

An aerobic growth of microorganisms has the advantage of avoiding unpleasant odors and the release of greenhouse gases, elements that one could have for example with fermentation products under growth conditions anaerobic, as in an all water tank for example.

According to the invention, the multiplication of aerobic microorganisms takes place on non-living calibrated lignocellulosic compounds 22 which serve as a support for microbial growth. Thus, within the pretreatment tank 21, the growth of aerobic microorganisms, on the inanimate calibrated lignocellulosic compounds 22 in the presence of EU wastewater, allows mineralization of the organic matter.

The term “mineralization” is understood to mean the transformation of the complex organic compounds present in EU wastewater into simple mineral compounds.

[0100] Simple mineral compounds have the advantage of being assimilable by plants, in particular reeds, and of being soluble in the liquid effluents passing through the pre-treatment tank 21 from top to bottom. The simple mineral compounds are found in the EP pretreated water at the outlet of the pretreatment tank 21.

[0101] According to a particular embodiment of the invention, in addition to the micro

aerobic growth organisms, said pre-treatment tank 21 may include earthworms capable of growing on the inert cellulose material 22, in particular on the surface of the wood chips.

[0102] The presence of earthworms has the effect of accelerating the process of

mineralization. In fact, earthworms make it possible to degrade the solids contained in EU wastewater, but also to aerate, by their

displacement on the surface of wood chips, the growth medium of aerobic microorganisms. [0103] In fact, the movement of earthworms in the tank causes aeration which increases the proportion of oxygen accessible to aerobic microorganisms. An increase in oxygen, accessible to aerobic microorganisms, increases the kinetics of microbial growth within the pre-treatment tank 21, hence improving the mineralization process of the complex organic compounds contained in the EU wastewater. In addition, earthworms feed on the organic matter deposited on the surface of the inert lignocellulosic material 22 and mineralize it directly. The presence of earthworms makes the process of mineralization by aerobic microorganisms more efficient.

[0104] According to another specific feature of the invention, as can be seen in FIG. 2, in order to further aerate the environment inside the pre-treatment tank 21, the pre-filter device 2 on lignocellulosic material 22 also comprises ventilation means 24.

[0105] For example, the ventilation means 24 consist of chimneys

ventilation systems as shown in Figure 2, which are advantageously connected to the pre-treated water evacuation means 5.

[0106] The presence of the aeration means 24 within the tank 21 allows

to ensure the aerobic environment necessary for aerobic microbial growth and mineralization process.

[0107] In other words, the solids contained in the waste water EU, arriving within the pre-treatment tank 21, will accumulate over time on the surface of the inert lignocellulosic material 22, that is to say. ie wood chips, then mineralize.

[0108] It should be noted that according to the invention, within the pretreatment tank 21, the process of aerobic mineralization of the solids contained in the EU wastewater is advantageously comparable to a process of

composting.

[0109] The role of the inert lignocellulosic material 22 is to filter and retain the

solids contained in EU wastewater. These solids retained on the surface of the inert lignocellulosic material 22 will then be mineralized by the aerobic microorganisms. [0110] Thus, the pre-filter device 2 on inert lignocellulosic material 22 makes it possible to screen the solids present in the EU wastewater.

[01 11] Thus, according to the invention, the prefilter device 2 on material

Inert lignocellulosic 22 acts as a phase separator for the incoming EU wastewater. Indeed, the solids remain on the surface of the wood chips, while the dissolved constituents of the EU wastewater will percolate towards the bottom of the pre-treatment tank 21. The constituents of EU wastewater, mineralized by microorganisms, emerge. on means of evacuation 5 of pre-treated water EP.

[01 12] According to the invention, the means 5 for discharging the pre-treated EP water are configured to discharge the pre-treated EP water outside the pre-filter device 2.

[01 13] In other words, EU wastewater which has undergone the process of

mineralization and filtration by gravity within the treatment tank 21, will be qualified and called EP pretreated water. Thus, said waters

pretreated EP contain only simple mineral compounds assimilable by plants.

[01 14] Advantageously, with the book 1 of the invention, it is possible to recover the excess solids at the surface of the inert lignocellulosic material 22. Recovery can be done by opening the opening means 23 of the pre-treatment tank 21. The excess solids can be reused and 100% natural. For example, the excess solids can be used as garden compost.

[01 15] In addition, the wood chips also being a biodegradable and compostable material, they will undergo a mineralization process over time, in the same way as the solid organic matter resulting from EU wastewater.

It is possible to recover them with mineralized solids on their surface, to use them as compost. This has the advantage of facilitating the maintenance and operation of the sanitation structure 1. Thus, the sanitation structure of the invention 1, through its pre-filter device 2 on inert lignocellulosic material 22 allows a valuation of sludge and inert lignocellulosic material 22 itself in compost

reusable.

[01 16] According to the invention, the distance, called "revenge", separating the surface

top of the inert lignocellulosic material 22 of the outlet of the means 4 for introducing wastewater EU has a height "h" of between 30 and 60 cm, as shown in Figure 2.

[01 17] Thus, the contrast of 30 to 60 cm allows a uniform distribution of the waste water EU on the surface of the inert lignocellulosic material 22. Thus, in the sanitation structure 1, the distance separating the inlet pipe for wastewater EU into the pre-treatment tank 21, with the upper surface of the inert lignocellulosic material 22 is to be taken into consideration for the sustainability of the 'work.

[01 18] In fact, a good distribution of EU wastewater at the surface improves the process of mineralization by aerobic microorganisms and the process of separation between the solid and liquid phases of EU wastewater.

[01 19] In addition, the contrast of 30 to 60 cm, constituting an accumulation space for the organic material, makes it possible to avoid the phenomenon of clogging of the inert lignocellulosic material 22 within the pretreatment tank 21. In fact , the other hand makes it possible to create a jet of waste water EU on the surface of the inert lignocellulosic material 22 which will aerate the waste water and stir up the sludge deposit that may form on the upper layer of the inert lignocellulosic material 22, so as to prevent 'it does not agglomerate, while providing oxygen by physical displacement and surface eddies.

[0120] According to a particular embodiment of the invention, the means

EP pre-treated water outlet 5 consists of a drainage pipe.

[0121] According to a preferred embodiment of the invention, said drainage pipe is made of PVC, with a diameter greater than or equal to 100 mm, said pipe is traversed by slots having the role of collecting the EP pretreated water. The evacuation means 5 make it possible to collect the pretreated water EP at the bottom of the pretreatment tank 21. [0122] According to a particular embodiment of the invention, said means 5 for discharging the pre-treated water EP comprise a lifting pump or a flushing structure, so as to control the volume and the inlet flow rate of the pre-treated water. EP feeding vertical flow planted filter device 3.

[0123] According to the invention, the means 5 for evacuating the pre-treated water EP

lead directly to the planted vertical flow filter device 3.

[0124] According to a first embodiment, if the gradient of the land allows it, the transport of the EP pretreated water by the evacuation means 5 is done by gravity or by a hydraulic flushing device.

[0125] According to a second embodiment, in the event of tilting terrain

insufficient, the transport of the EP pretreated water by the evacuation means 5 is done using a lifting pump. Said lifting pump makes it possible to transport the pre-treated EP water directly to the single vertical flow planted filter device 3, or to the first vertical flow planted filter device 3 which is in the series.

[0126] Indeed, the sewage works 1 for EU wastewater comprises, downstream of the pre-filter device 2, said planted filter device with vertical flow 3.

According to the present application, the flow of water to be treated is from upstream to downstream of the sanitation structure 1.

[0127] The nature of the water changes between upstream and downstream. In fact, upstream we have raw EU wastewater, that is to say at the inlet of the pre-filter device 2. In the same way, between upstream and downstream, that is to say between the pre-filter device 2 and the first planted vertical flow filter device 3, there is pre-treated water EP. Then, to finish downstream, we have ET treated water which is at the outlet of the last planted filter device with vertical flow 3.

In the same way and as can be seen in FIG. 1, the nature of the devices that the sanitation structure 1 comprises changes between upstream and downstream. In fact, upstream there is always the pre-filter device 2 and downstream there is at least one planted filter device with vertical flow 3. [0129] According to the invention, said planted filter device with vertical flow 3, as shown in FIG. 5, comprises means 12 for distributing the pretreated water EP at the outlet of the discharge means 5.

[0130] According to a preferred embodiment, said means 12 for distributing the pre-treated EP water consist of a series of drains or distribution nozzles partially covering and in a homogeneous arrangement the upper surface of the planted filter device with vertical flow 3 .

[0131] Thus, according to the invention, the distribution means 12 distribute the EP pretreated water on the surface of the filter unit of the planted filter device with vertical flow 3.

The term "filter bed" is understood to mean the filter device planted at

vertical flow 3, the culture and growth medium of semi-aquatic plant species 13 allowing the treatment and complete filtration of the EP pretreated water.

[0133] For example, said semi-aquatic plant species 13 may be common reeds of the Phragmites australis type, sedges belonging to the Cyperaceae family, marsh irises, for example of the Iris type.

pseudacorus, loosestrife for example of the Lythrum salicaria type, baldingera of the Phalaris arundinacea type or a random mixture of all these species.

[0134] According to the invention, the semi-aquatic plant species 13, such as

visible in Figures 1, 4 and 5, form a root network allowing vertical drainage of EP pretreated water within the filter bed. This network and root tissue forms galleries in the filter bed.

[0135] These galleries provide oxygen to the aerobic bacteria of the rhizosphere and further accentuate the mineralization process.

[0136] Thus, within the filtering mass, the aerobic bacteria of the rhizosphere

break down the residual organic matter contained in EP pretreated water into simple compounds. These simple compounds can be assimilated directly by semi-aquatic plant species 13. [0137] For example, said simple compounds consist of nutrients such as phosphorus or nitrogen but also of carbon molecules.

[0138] According to a particular feature of the wastewater treatment structure 1 EU of the invention, said planted vertical flow filter device 3 consists of a single filter unit intended to treat the EP pretreated water from the Pre-filter device 2. In fact, the purification structure 1 of the waste water EU of the invention comprises a planted filter with vertical flow 3 which aims to finely and completely treat the pre-treated water EP. The planted vertical flow filter 3 requires only a single filter block to treat the EP pretreated water and not two filter blocks arranged in parallel operating alternately as in the prior art.

[0139] In fact, the configuration of the drainage structure 1 is such that it is not necessary, in order to avoid clogging at the surface of the filter block, to have two filter blocks on the same stage supplied with alternation with water to be treated.

[0140] Unlike planted filter devices with vertical flow

existing ones, the sanitation structure 1 makes it possible to structurally dissociate in two devices, communicating with each other, the pre-treatment phase and the wastewater treatment phase.

[0141] Thus, advantageously, the pretreatment phase, in particular the treatment of the solids is not done in the same device, which makes it possible to recover the sludge in order to use it as compost without having to stop the operation of the system. .

[0142] According to the invention, the drainage structure 1 can operate continuously without there being a risk of clogging of the filter bed.

[0143] According to another advantage of the invention, the foul odors are not present with the sanitation structure 1 of the invention because the pre-treatment tank 21 is sealed and closed, and there is no fermentation of the organic matter but a mineralization which gives off little or no odor. [0144] In addition, as the filter bed only treats EP pretreated water, a rest phase is not necessary to avoid clogging of the bed, as is the obligation to have two beds in parallel operating alternately.

[0145] With the sewerage structure 1, the floor area in m ² of the planted vertical flow filter device 3 required is reduced compared to a planted vertical flow filter device 3 to treat the same volume. of EU wastewater.

[0146] In the same way, with the sanitation structure 1, the cleaning of the

The surface of the filter bed of the planted vertical flow filter device 3 is no longer necessary, since the solid organic matter arrives on the filter bed in the form of simple mineral compounds that can be assimilated by plants.

[0147] According to a first embodiment of the invention, the filter bed is not waterproof, which allows the treated water AND to infiltrate directly into the ground through the bottom of the filter bed. In this case, the soil is also partly involved in the treatment and purification of the water. However, this first embodiment is subject to site constraints, such as the permeability of the soil, the presence or not of the water table, local regulations in terms of water purification.

[0148] According to a preferred embodiment visible in Figures 1, 4 and 5, the filter bed of the planted vertical flow filter device 3 is sealed, that is to say that it does not communicate directly with the ground. Thus, it is possible to recover the ET treated water at the bottom of the filter bed.

[0149] The recovery of ET treated water is carried out, for example, using drainage means 7 for ET treated water. Said drainage means 7 are configured to drain the treated water AND out of said at least one planted filter device with vertical flow 3.

[0150] A sealed filter unit makes it possible to recycle ET treated water.

For example, the treated water ET, at the outlet of the drainage means 7, can be used as domestic water in the dwelling or also as water for watering a garden or the like. Thus, the drainage means 7 of the treated water ET make it possible to collect it, for example within a drain network to either reuse them as feed for a flushing toilet or throw them back into the natural environment.

[0151] The filter bed allows in-situ treatment of EP pretreated water by

from the prefilter device 2 on inert lignocellulosic material 22.

[0152] More specifically, according to the invention, said "filter bed" is a mineral substrate, which comprises at least three superimposed layers of minerals of different particle size, nature and thickness.

As visible in Figure 1 and Figure 4, these three layers of minerals are superimposed from the soil surface to the bottom of the filter planted in this order:

- a filter layer 8,

- a transition layer 9,

- a draining layer 10.

According to a particular embodiment of the invention, said filter bed consists of three layers of minerals including a filter layer 8 in the upper part surmounted by a transition layer 9, the latter itself surmounting a draining layer 10 located in the lower part of the filter bed.

[0155] According to a preferred embodiment, the filter layer 8 consists of a layer of sand with a particle size of between 0 and 6 mm.

[0156] Said filter layer 8 is the treatment layer for EP pretreated water, the fine grain size of the sand grains makes it possible to retain the fine particles remaining in the EP pretreated water. The sand constitutes a fixed growing medium. In fact, the bacteria developing around the grains of sand and around the roots of semi-aquatic plant species 13 provide the refined treatment of the EP pretreated water.

[0157] Advantageously, the total thickness of the filter layer 8 is included

between 20 and 50 cm, it varies according to the physicochemical characteristics of the sand. A filter layer 8 thickness between 20 and 50 cm allows the complete treatment of EP pretreated water by aerobic microorganisms of the rhizosphere. [0158] Advantageously, the filter layer 8 consists of sand. Said sand of the filter layer 8 consists of mineral matter which is predominantly siliceous, non-calcareous, so as to ensure its durability over time. Indeed, the water entering the filter bed can have an acidic pH. This acidity can lead over time to a risk of alteration of mineral materials, in particular if they are calcareous in nature. In other words, the sand of the filter layer 8 may deteriorate on contact with the EP pretreated water which may have an acidic pH. This is why it is preferable to use a non-calcareous sand less friable, more stable, in contact with acidic water.

[0159] In addition, calcareous minerals tend to compact over time, becoming impermeable, hence a risk of the layer clogging. This is why the use of limestone sand for the filter layer 8 is not recommended in order to avoid its clogging.

Preferably, the filter layer 8 is washed / rolled. In other words, the mineral materials constituting the layer are washed, that is to say they are freed of their impurities and in particular of fine particles to avoid contamination of the water which is to be treated. and clogging of the mass by these same impurities. In addition, the mineral matter constituting the layer is rolled, that is, the grains are rounded through a process of erosion by water. Unlike grains with protruding ridges, a layer of mineral matter with rounded grains which are rolled helps promote the filtration process.

[0161] As seen in Figure 4, below the filter layer 8, the filter bed comprises a transition layer 9. The transition layer 9 is essential to structurally maintain the filter bed of the planted filter device with vertical flow 3.

More specifically, the transition layer 9 is essential to prevent the sand of the filtration layer 8 from coming into contact with the draining layer 10 defined subsequently. The transition layer 9 therefore has no effect as such in the treatment of EP pretreated water, but an effect on the maintenance of the structure of the filter bed. In other words, the transition layer 9 only allows the passage of liquid effluents to the draining layer 10. The transition layer 9 makes it possible to retain the filter layer 8 so that the sand does not end up at the level of the draining layer 10 as the EP pretreated water passes.

[0164] According to a preferred embodiment of the invention, the layer of

transition 9 has a thickness of between 5 and 15 cm and consists of a mixture of gravel with a particle size of between 2 and 10 mm.

In the same way and for the same reasons as mentioned above, the transition layer 9 is also preferably made of siliceous, non-calcareous mineral materials, with washed and rolled grains.

As shown in Figure 4, below the transition layer 9 and constituting the bottom of the filter bed, there is the draining layer 10.

[0167] The role of the draining layer 10 is to drain the treated water AND in order to collect it towards the drainage means 7 as visible in FIG. 1 and in FIG. 4. The draining layer 10 therefore opens onto the drainage means. 7.

[0168] ET treated water can be discharged into the natural environment or even recovered for recycling, for example to water the garden or to supply household devices for household use of the flushing toilet type after additional treatment of disinfection.

[0169] According to a preferred embodiment of the invention, the layer of

drainage 10 has a thickness of between 10 and 40 cm thick, preferably between 10 and 20 cm thick and consists of coarse gravel with a grain size of between 10 and 40 mm.

[0170] In the same way and for the same reasons as mentioned above, the

Drainage layer 10 is also preferably made of siliceous, non-calcareous inorganic materials with washed and rolled grains.

[0171] According to a specific feature of the invention, the water drainage means 5

pretreated EP open directly and merge with the means 12 for distributing the pretreated EP water, so that the prefilter device 2 communicates directly with the upper part of the filter bed, near the ground surface, that the planted flow filter device comprises 3.

[0172] According to the invention, the distribution means 12 of the EP pretreated water are positioned in the extension of said discharge means 5. More specifically, these distribution means 12 are supplied by these discharge means 5.

[0173] According to one embodiment of the invention, the distribution means 12 consist for example of a single drain placed on the surface of the filter layer 8.

[0174] According to a preferred embodiment of the invention, the means 12 for distributing the EP pretreated water consist of an H-shaped or U-shaped ramp placed on the surface of the filter layer 8 so as to distribute uniformly over the massive filtering pre-treated EP water.

[0175] According to a first embodiment, the feed of EP pretreated water consists of a gravity feed. In this case, the means 12 for distributing the EP pretreated water consist of PVC-type pipes having a minimum diameter of 100 mm, in order to avoid obstruction of the pipe and a lack of fluidity.

[0176] According to a second embodiment, the supply of EP pretreated water consists of a supply by lift pump and under pressure. In this case, the means 12 for distributing the EP pretreated water preferably consist of pressure PVC type pipes having a minimum diameter of 50 mm, in order to avoid obstruction of the pipe and a lack of fluidity.

[0177] According to a particular embodiment of the sanitation structure 1 of the invention, and as visible in FIG. 1 and in FIG. 4, above said filter layer 8, the filter unit of the device vertical flow planted filter 3 may further include a sanitary protection layer 11.

Said sanitary protective layer 11 has the role of at least partially covering said distribution means 12 of the pre-treated water EP, so as to keep them in position against the filter layer 8. The protective layer sanitary 1 1 also makes it possible to prevent unauthorized persons, for example children, from having access to the distribution means 12 and from being in contact with the EP pretreated water.

[0179] In addition, the sanitary protection layer 1 1 also makes it possible to visually conceal the distribution means 12, so that the planted filter device with vertical flow 3 remains aesthetic by showing only the semi-aquatic plant species 13.

[0180] Even if the sanitary protective layer 1 1 is not compulsory and has no functional role in the filtration and treatment of EP pretreated water, it is of interest for the implementation of the work of sanitation 1.

[0181] According to a preferred embodiment of the invention, the layer of

sanitary protection 1 1 has a thickness between 10 and 20 cm, and consists of coarse gravel with a grain size of between 10 and 40 mm.

[0182] The present invention also relates to a wastewater purification process implemented by the purification structure 1 in which:

- the said pre-treatment tank (21) is supplied directly with waste water (EU) using the introduction means (4),

- the suspended matter contained in the wastewater (EU) is filtered and mineralized within said pretreatment tank (21) until a pretreated water (EP) is obtained at the bottom of the pretreatment tank (21) ),

- at the bottom of said pretreatment tank (21), said pretreated water (EP) is recovered in evacuation means (5),

- said pre-treated water (EP) is transferred directly to the filter bed of the planted vertical flow filter device (3) using the means of evacuation,

- said pretreated water (EP) is treated by passing through said filtering mass until treated water (ET) is obtained,

- said treated water (ET) is drained outside the filter bed and the planted filter device with vertical flow (3),

- said treated water (ET) is directed to the natural environment or to a domestic water recycling network. [0183] According to the method of the invention, said water recycling network

domestic, for example, consists of a network for the circulation of treated water (ET) to the home of the piping type allowing to operate a toilet flush after additional treatment of the type

disinfection or a garden hose.

[0184] According to the present invention, said sanitation structure 1 can be used as a water purifier, more specifically as a purifier of domestic EU wastewater into treated water AND intended to be discharged into a natural environment or to be recycled. in a domestic water network circuit for certain regulated uses.

[0185] Thus, the purpose of the sanitation structure 1 of the invention is to directly treat the EU wastewater leaving a dwelling, without it being necessary to have an all-water tank giving off foul odors. or a preliminary screening before treatment.

[0186] In fact, the sanitation structure 1 makes it possible to transform directly and on its own, the EU wastewater into EP pretreated water and then into ET treated water. The process of transformation and treatment of water can be carried out continuously, without it being necessary to have rest phases of filtration of the filtering mass of the planted filter device with vertical flow 3. Indeed, a supply of continuous flow of the planted filter device with vertical flow 3 is possible because the risk of clogging of the upper surface of the filter unit supplied only with pre-treated EP water is zero. Likewise, a continuous supply of the prefilter device 2 does not pose any problem of clogging of the prefilter.

The process of transformation and treatment of water can also be done discontinuously, without there being a problem of loss of efficiency of the filtration activity of the prefilter device 2 or of stagnation of organic matter. on the surface of the filtering mass of the planted filter device 3. In fact, as the sanitation structure is autonomous in its operation, no surface cleaning is necessary, a discontinuous supply of EU wastewater does not generate no malfunction in the water treatment. [0188] In addition, compared with existing devices for purifying water, in particular with existing vertical flow planted filter devices, the sanitation structure of the invention requires a smaller deployment surface on the ground.

[0189] In fact, the deployment surface on the ground for a wastewater treatment device can be expressed in m ² / pe called "square meter per Inhabitant Equivalent".

The m ² / pe unit of measurement corresponds to the floor area necessary for the treatment device to treat the polluted water generated by a person living in a habitat. The m ² / pe allow the dimensioning of the

water treatment and reflects the hydraulic and organic load produced by a person over a day. In France, a Inhabitant Equivalent called EH corresponds to approximately 150 liters of wastewater per day with a standard pollution load of 60 g of biochemical oxygen demand over 5 days and 120 g of chemical oxygen demand.

[0191] While the planted vertical flow filter devices of the art

previous require 1, 2 to 2 m ² / pe and at least two filtering beds per stage supplied alternately, the drainage structure 1 requires only 0.5 to 1 m ² / pe for its planted filter device vertical flow 3 and from 0.25 to 1 m ² / pe for the prefilter device 2 on inert lignocellulosic material 22. Thus, the sanitation structure 1 according to the invention makes it possible to reduce the m ² / pe necessary for the treatment of wastewater EU compared with the devices for treating wastewater EU of the prior art.

[0192] In addition, the sanitation structure 1 of the invention makes it possible to dispense with an all-water tank, a step of prior screening of organic matter, a step of cleaning the filter block for the planted filter device with vertical flow, the establishment of an alternating supply system, a system to control the water flow and volume of incoming water and the physicochemical conditions of the soil.

[0193] The sanitation structure 1 according to the invention therefore consists of a wastewater treatment solution that is at the same time efficient, simple, reliable and ecological, making it possible to have compost that can be used in the field.

Claims

[Claim 1] Wastewater (EU) purification structure (1) characterized in that it comprises:

- means of introduction (4) of wastewater (EU);

- a pre-filter device (2) on inert lignocellulosic material (22), this pre-filter device (2), on the one hand, is configured to transform wastewater (EU) into pre-treated water (EP) and, on the other part, comprises a sealed and closed pre-treatment tank (21), which is supplied with waste water (EU) by the means

introduction (4) of wastewater (EU), and which internalizes compounds

calibrated non-living cellulose and aerobic microorganisms;

- means of evacuation (5) of the pre-treated water (EP) which are configured to evacuate the pre-treated water (EP) outside the pre-filter device (2);

- at least one planted filter device with vertical flow (3), which is configured to transform pre-treated water (EP) into treated water (ET), which is arranged in series and positioned downstream of said pre-filter device (2), which is supplied with pre-treated water (EP) by the evacuation means (5) of the pre-treated water (EP),

- Said planted filter device with vertical flow (3) comprises, on the one hand, distribution means (12) of the pre-treated water (EP), which are positioned in the extension of said means (5) of evacuation of the pre-treated water (EP) and which are fed by these evacuation means (5) of the pre-treated water (EP), and, on the other hand, a filtering mass, which is surmounted by the distribution means (12) of the pre-treated water (EP) ), and which constitutes a culture medium for semi-aquatic plant species (13),

- said filter bed comprises at least three layers of minerals including a filter layer (8) which is located in the upper part of the filter bed, a transition layer (9) which is surmounted by the filter layer (8), and a draining layer (10) which is surmounted by the transition layer (9) and which is located in the lower part of the filter mass;

- Drainage means (7) of the treated water (ET), onto which the draining layer (10) emerges, and which are configured to drain the treated water (ET) outside said at least one planted filter device with vertical flow (3).

[Claim 2] Sewage (EU) purification works (1), according to the preceding claim, characterized in that:

- the filter layer (8) consists of a layer of sand with a grain size between 0 and 6 mm,

- the transition layer (9) consists of a layer of gravel with a particle size between 2 and 10 mm,

- the draining layer (10) consists of a layer of coarse gravel with a particle size of between 10 and 40 mm.

[Claim 3] Sewage (EU) purification works (1), according to any one of the preceding claims, characterized in that:

- the filter layer (8) has a thickness between 20 and 50 cm,

- the transition layer (9) has a thickness between 5 and 15 cm,

- the draining layer (10) has a thickness of between 10 and 20 cm thick.

[Claim 4] Sewage (EU) purification works (1), according to any one of the preceding claims, characterized in that the filter layer (8) and / or the transition layer (9) and / or the draining layer (10) is composed (s) of predominantly siliceous, non-calcareous, washed and rolled mineral materials.

[Claim 5] A work for the purification (1) of waste water (EU), according to any one of the preceding claims, characterized in that said filtering mass comprises, above said filter layer (8), a layer of health protection (11) covering at least part of said distribution means (12) of the pre-treated water (EP).

[Claim 6] Sewage (EU) purification work (1), according to any one of the preceding claims, characterized in that said means (4) for introducing sewage (EU) consist of a pipe of which the outlet end, feeding the pre-treatment vessel (21), is positioned above the upper surface of the compounds

lignocellulosic at a height distance of between 30 and 60 cm.

[Claim 7] Sewage (EU) purification works (1), according to any one of the preceding claims, characterized in that that said means (4) for introducing waste water (EU) and / or said means for discharging (5) pre-treated water (EP) comprise a lifting pump or a flushing structure.

[Claim 8] Sewage (EU) purification work (1), according to any one of the preceding claims, characterized in that the calibrated non-living lignocellulosic compounds, within the pretreatment tank (21), are present in the form of an assembly of wooden plates with a thickness of between 30 and 60 cm.

[Claim 9] Sewage (EU) purification work (1), according to any one of the preceding claims, characterized in that said distribution means (12) of the pretreated water (EP) consist of a distribution ramp , preferably an H-shaped or I-shaped or U-shaped drain, placed directly on the filter layer (8).

[Claim 10] Sewage (EU) purification work (1), according to any one of the preceding claims, characterized in that said pretreatment tank (21), internalizing compounds

lignocellulosic and aerobic microorganisms, additionally includes earthworms.

[Claim 1 1] A method of sanitizing wastewater implemented by the sanitation structure 1 according to any one of the preceding claims in which:

- said pre-treatment tank (21) is supplied directly with waste water (EU) using the introduction means (4);

- the suspended matter of the wastewater (EU) is filtered and mineralized within said pretreatment tank (21) until a pretreated water (EP) is obtained at the bottom of the pretreatment tank (21),

- Treating said pretreated water (EP) by passing through said filtering mass until treated water (ET) is obtained, - said treated water (ET) is drained outside the filter bed and the planted filter device with vertical flow (3),

- said treated water (ET) is directed to the natural environment or to a domestic water recycling network.

[Claim 12] Use of the wastewater (EU) sewerage (1), according to any one of claims 1 to 8, as a water purifier. |