FR3109094A1 - Process of treatment and degradation of organic micropollutants by fermentation of plants - Google Patents

Abstract

Process for treating and degrading organic micropollutants by fermentation of plants The present invention relates to a technique for treating and degrading organic micropollutants contained in cultivated plants from wastewater, treated water leaving treatment stations and rainwater. In the present case, these plants, which are more precisely reeds and nettles, absorb organic micropollutants contained in polluted water. They are then harvested and then immersed in water to trigger fermentation. The fermentation process is driven by a targeted analysis of micropollutants and by reduction objectives compared to the quantities initially detected. The process according to the invention is particularly intended to destroy organic micropollutants contained in nettles and in reeds used for wastewater treatment or which have been cultivated by water containing pollutants. Figure to be published with the abstract: Fig. 1.

Description

Treatment process and degradation of organic micropollutants by plant fermentation

FIELD OF THE INVENTION TO WHICH THE INVENTION RELATES

The invention relates to the field of techniques for the treatment and degradation of organic micropollutants contained in cultivated plants from wastewater, treated water leaving treatment stations and rainwater.

PRIOR ART

To date, plants from wastewater treatment processes are little valued because of the organic micropollutants they contain.

Also, treated water leaving treatment plants and rainwater from urban areas and roads are, in most cases, discharged into bodies of surface water such as rivers and the seas.

They contribute to the degradation of natural environments partly due to the pollution they contain. Pollution partly contains organic micropollutants. Many studies have shown that these micropollutants from medicines, household products, cosmetics, petroleum derivatives have a very strong impact on the environment, especially bodies of water. These then enter the food chain via fish or other animals that interact with this ecosystem.

Treated water is little used in agriculture because of the micropollutants it contains and which ultimately end up in plants and can therefore enter the food chain.

It has also been found that macropollutants such as nitrogen and phosphorus also contribute strongly to the degradation of water bodies. They considerably modify the ecosystems and even, to the extreme, sterilize them by eutrophication.

However, nitrogen and phosphorus are primarily nutrients used in agriculture. These nutrients become a valuable resource.

To our knowledge, there is no technique for treating plants grown from wastewater.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a technique for the treatment and degradation of organic micropollutants contained in plants grown from waste water, treated water leaving treatment stations and rainwater.

In this case, these plants are more precisely reeds and nettles. These plants absorb the organic micropollutants contained in polluted water. They are then harvested and then immersed in water to trigger fermentation.

This process of treatment and degradation of organic micropollutants contained in plants grown from wastewater, treated water leaving treatment plants and rainwater includes in the first step the introduction of harvested plants with a large number of organic micropollutants. detected and water in a container.

The process continues with a stage of fermentation of the contents of the container.

Preferably, to control this fermentation step, the presence of organic micropollutants within the contents of the container is analyzed.

This analysis of the presence of organic micropollutants is a targeted analysis by chromatography of a selection of organic micropollutants.

This selection of micropollutants includes at least several hundred micropollutants from a list of potential micropollutants that contains pesticides, drugs, personal hygiene products, household products, plastic derivatives and other toxic products.

In a practical way, thresholds for reducing the quantities of micropollutants initially detected in abundance or in strong presence are set up.

It is advantageous if the process includes an analysis of the presence of pathogens such as bacteria and viruses within the contents of the container.

Similarly, thresholds are set for reducing the quantities of pathogens such as bacteria and viruses initially detected within the contents of the container.

In terms of device, the device for the treatment and degradation of organic micropollutants contained in plants grown from waste water, treated water leaving treatment stations and rainwater comprises a container and a content.

The container is a globally closed container to be protected from oxygen, i.e. under anaerobic conditions, with means to introduce the cultivated plants and means to evacuate the gases resulting from fermentation.

The content includes harvested plants with a large number of organic micropollutants detected and water. It probably also contains suspended solids.

In terms of use, this device is used for the fermentation of the contents of the container under anaerobic conditions.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference is made to the appended drawings.

shows in section the starting stage of the treatment process for organic micropollutants contained in nettles.

shows in section the final stage of the treatment process for the organic micropollutants contained in the nettles.

shows in section the starting stage of the treatment process for organic micropollutants contained in reeds.

shows in section the final stage of the treatment process of the organic micropollutants contained in the reeds.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a technique for the treatment and degradation of organic micropollutants contained in plants (2) grown from waste water, treated water leaving treatment stations and rainwater from urbanized surfaces and roads.

The technique according to the invention makes it possible to use water of various origins which may contain macropollutants and/or organic micropollutants in order to cultivate plants. These plants (2), which in our present case are nettles (2A) and reeds (2B), are harvested and then undergo a treatment allowing the degradation of organic micropollutants. On the other hand, this process allows the conservation of nutrients and trace elements contained in the plants. Thus the final product can be valued. The invention therefore makes it possible to transform a large number of disadvantages into advantages. It makes it possible to take advantage of water and nutrients while treating a large majority of organic micropollutants.

It is made up of several stages of production.

First of all, beforehand the steps of a classic process of growing plants from wastewater, treated water coming out of treatment plants and rainwater are as follows.

Waste/treated/rainwater is used to grow, via irrigation systems, plants (2) such as nettles (2A), reeds (2B) and trees.

So these plants (2) absorb water to meet their water needs.

Also these plants (2) absorb nutrients to meet their nutritional needs.

At the same time, these plants (2) absorb organic and inorganic micropollutants.

Partly the plants (2) degrade part of the organic micropollutants during their growth and development.

On the other hand, another fraction of micropollutants is stored within plants (2).

Finally the plants (2) are harvested.

The stages of the treatment process according to the invention of the plants (2) thus harvested are as follows.

In a first step, these plants (2) are introduced into a container (1) and are then immersed in water (4) in this same container (1).

One of the objects of the invention is that this mixture of water (4) and plants (2) causes fermentation in order to degrade organic micropollutants.

For this purpose, avoid using chlorinated water.

Preferably, this fermentation will take place in the absence of oxygen.

One or more active substances acting as a catalyst can be added.

In order of magnitude, the mass of water (4) added is a factor of 10 compared to the mass of plants (2) introduced.

Figure 1 shows in section the starting stage of the treatment process for organic micropollutants contained in nettles (2A).

Referring to this drawing, the device (D) comprises a container (1) with an orifice containing nettles (2, 2A), suspended solids (3), water (4), a tube (5) , a plug (6) for obstructing the orifice, a support (7).

This arrangement makes it possible to carry out the fermentation in an almost closed container (1), with an orifice large enough to be able to introduce the plants (2), and once the plants (2) have been introduced, to close the container (1) with a plug ( 6), cap (6) provided with a vent tube (5).

The vent tube (5) allows the gases produced by the fermentation to be evacuated. These gases resulting from fermentation can simply be released into the open air. They can also be processed and potentially exploited.

In this embodiment to illustrate the invention, the container (1) is only a few liters.

According to other embodiments, the container (1) may have a shape, an orifice, a support and a volume different from that represented as long as it allows the fermentation process as described with equivalent functionalities.

In particular, the container (1) can in an industrial process take the size of a tank, a cistern with a wide opening.

Figure 2 shows in section the final stage of the treatment process for organic micropollutants contained in nettles (2A).

Referring to this drawing, the device (D) comprises a container (1) with an orifice containing nettle residues (2A), suspended solids (3), water (4), a tube (5) , a plug (6) allowing the obstruction of the orifice, a support (7). Note that the contents of container (1) are in solute form.

Figure 3 shows in section the starting stage of the treatment process for the organic micropollutants contained in the reeds.

Referring to this drawing, the device (D) comprises a container (1) with an orifice containing reeds (2, 2B), suspended solids (3), water (4), a tube (5) , a plug (6) for obstructing the orifice, a support (7).

Figure 4 shows in section the final stage of the treatment process for the organic micropollutants contained in the reeds.

Referring to this drawing, the device (D) comprises a container (1) with an orifice containing reed residues (2B), suspended solids (3), water (4), a tube (5), a cap (6) allowing the obstruction of the orifice, a support (7). Note that the content of container (1) is in solute form.

To control the micropollutant degradation process during fermentation, it is advantageous to analyze the presence of micropollutants in the solute.

Preferably for this analysis, it is preferred to detect organic micropollutants by a targeted analysis by chromatography of a list of potential organic micropollutants.

Among the micropollutants sought, most of them appear in the list of emerging pollutants produced by national and European agencies.

For example in France, this list must notably include emerging micropollutants classified as hazardous substances by the European framework directive on water and the national micropollutants plan 2016-2021. Also, this research must also integrate the list of micropollutants appearing in the technical note of 01/29/18 relating to the search for micropollutants in raw water and in treated wastewater from wastewater treatment plants and their reductions concerning Overseas Departments and Regions.

This list contains pesticides, drugs, personal hygiene products, household products, plastic derivatives and other toxic products.

It is recommended to carry out broad-spectrum analyzes of micropollutants.

The recommended methodology is sensitive enough to detect traces of micropollutants (<μg/l).

Thus piloted, the fermentation process will take several days, even weeks, until the reduction to a very low presence of organic micropollutants in the solute is observed.

In terms of threshold, it is recommended to set thresholds as an example where out of about a thousand potential organic micropollutants, the fermentation process has divided on average the micropollutants initially detected in abundance by a factor of at least 5 and those in strong presence in a factor of at least 2.

It is advantageous if the process includes an analysis of the presence of pathogens such as bacteria and viruses within the contents of the container (1).

Similarly, thresholds are set for reducing the quantities of pathogens such as bacteria and viruses initially detected within the contents of the container (1).

For example in France, an objective would be to achieve the level of sanitary quality of treated wastewater of quality A by analogy with the decree of August 2, 2010 relating to urban wastewater.

Finally after fermentation, the presence of nutrients such as nitrogen and phosphorus is measured.

In terms of industrial application, the treatment process according to the invention is particularly intended for the treatment of organic micropollutants contained in plants resulting from a crop irrigated by various polluted waters.

The present invention is in no way limited to the embodiments described and represented, but those skilled in the art will be able to add any variant to it in accordance with their spirit for a range of processes at different production scales.

Claims (12)

Process for the treatment and degradation of organic micropollutants contained in plants (2) grown from waste water, treated water leaving treatment stations and rainwater, characterized in that it includes the introduction of plants (2) harvested having a large number of organic micropollutants detected and water (4) in a container (1). Process according to Claim 1, characterized in that it includes a stage of fermentation of the contents of the container (1). Process according to Claim 2, characterized in that the process comprises an analysis of the presence of organic micropollutants within the contents of the container (1). Process according to Claim 3, characterized in that the analysis of the presence of micropollutants is a targeted analysis by chromatography of a selection of organic micropollutants. Process according to Claim 4, characterized in that the selection of micropollutants comprises at least several hundred micropollutants including pesticides, drugs, personal hygiene products, household products and plastic derivatives. Process according to Claim 4, characterized in that thresholds are set for reducing the quantities of micropollutants initially detected in abundance or in strong presence. Process according to Claim 2, characterized in that the process comprises an analysis of the presence of pathogenic agents such as bacteria and viruses within the contents of the container (1). Process according to Claim 7, characterized in that thresholds are set for reducing the quantities of pathogenic agents such as bacteria and viruses initially detected within the contents of the container (1). Process according to any one of Claims 1 to 8, characterized in that the plants (2) cultivated are nettles (2A). Process according to any one of Claims 1 to 8, characterized in that the plants (2) cultivated are reeds (2B). Device (D) for the treatment and degradation of organic micropollutants contained in plants grown from waste water, treated water leaving treatment stations and rainwater, characterized in that it comprises a container (1) whose content includes harvested plants (2) having a large number of organic micropollutants detected and water (4). Use of the device (D) according to Claim 11, characterized in that this device is used for the fermentation of the contents of the container (1) under anaerobic conditions.