Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F9/00—Multistage treatment of water, waste water or sewage
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/28—Treatment of water, waste water, or sewage by sorption
  • C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/76—Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/002—Grey water, e.g. from clothes washers, showers or dishwashers
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/005—Black water originating from toilets
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2303/00—Specific treatment goals
  • C02F2303/04—Disinfection
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2303/00—Specific treatment goals
  • C02F2303/26—Reducing the size of particles, liquid droplets or bubbles, e.g. by crushing, grinding, spraying, creation of microbubbles or nanobubbles
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/30—Aerobic and anaerobic processes
  • C02F3/301—Aerobic and anaerobic treatment in the same reactor
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/30—Aerobic and anaerobic processes
  • C02F3/302—Nitrification and denitrification treatment
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F3/00—Biological treatment of water, waste water, or sewage
  • C02F3/32—Biological treatment of water, waste water, or sewage characterised by the animals or plants used, e.g. algae
  • C02F3/327—Biological treatment of water, waste water, or sewage characterised by the animals or plants used, e.g. algae characterised by animals and plants
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

• TITLE Phyto-purification process and installation for the treatment of wastewater Technical field
• the invention relates to the field of methods and installations for the treatment of wastewater.
• the invention relates to the treatment of urban wastewater.
• the invention thus finds its application in particular in the field of water reuse.
• FR2984874B1 proposes a process and an installation for the reuse of wastewater implementing a biological treatment of water in a bioreactor by activated sludge then microfiltration of the water originating from this biological treatment then treatment of part of the filtrate obtained. by reverse osmosis.
• the other part of the filtrate can be reused in industry or for domestic purposes after having undergone a disinfection step for services that are not very demanding in terms of water quality.
• the permeate leaving the reverse osmosis unit is subjected to a conditioning treatment by mineralization followed by disinfection and can be used for more demanding services in terms of water quality.
• This type of technique which combines conventional biological treatment and membrane filtration by reverse osmosis, however has the drawback of being costly to realize and operate. Indeed, it involves in particular the use of aeration devices and reagents of the coagulant and flocculant type, depending on the separation technology used, to carry out the biological treatment, as well as the production of sludge by the latter. which also need to be dealt with at a later date.
• the mineralization step also consumes chemicals. The associated costs in terms of corresponding equipment and reagents are therefore high.
• Phyto-purification consists in creating an artificial wetland made up of basins filled with a mineral substrate and planted with plants, in particular macrophytes. These plants are selected for their root system and / or their highly developed rhizomes on which the biomass is fixed. These are mainly emerged macrophytes, such as for example Phragmites australis, Typha latifolia, Scripus Lacustris. Wastewater passes through such ponds, and macrophytes transfer oxygen through their root systems and rhizomes to the bottom of them, providing an environment below the water level that is conducive to leaching.
• a disadvantage of the use of phyto-purification to purify urban water lies in the surface necessary to implement it.
• An objective of the present invention is to provide a technique for treating wastewater making it possible to obtain treated water meeting high quality criteria, and thus allowing its reuse to be considered and thus reducing the consumption of water resources.
• Another object of the present invention is to disclose such a technique which, at least in some embodiments, allows complete reuse of wastewater without any release of waste to the environment.
• Another objective of the present invention is to provide such a technique which is less costly in energy than the techniques for reusing wastewater known from the prior art.
• An objective of the present invention is to disclose such a technique which does not produce sludge or odors.
• Another objective of the invention is to provide an installation for implementing such a method.
• Another objective is to offer decentralized wastewater treatment which allows water to be recycled for use in sustainable buildings, such as office buildings, hotels, housing estates, "eco-districts” or hamlets with of few natural water resources.
• a process for the biological treatment of wastewater using a bioreactor comprising a bed of chemically inert aggregate in which macrophytes emerged are rooted, characterized in that it comprises: a preliminary dilution step consisting in diluting the water to be treated according to a dilution ratio between 8 and 50 and preferably between 10 and 20, the organization of food and emptying said bioreactor with water thus diluted, according to tidal cycles lasting less than 2 hours, and preferably less than 1 hour, during each of which at least part of said bed of chemically inert aggregate is depleted and then submerged by said water so as to provide in said bed of chemically inert aggregate successive periods of aeration and non-aeration, a step of evacuating the filtered water, said preliminary dilution step consisting in diluting said water to be treated with water originating at least in part from said process.
• the term “tidal cycle” therefore means a cycle during which the bioreactor is at least partly filled with diluted water and then emptied thereof.
• the proposed technique makes it possible to do away with the use of activated sludge and the associated drawbacks, by implementing a phyto-purification step under specific conditions that do not produce an odor and do not require large implantation surfaces.
• the reduction in the organic matter content of water is essentially effected by the biofilm developing on the surface of the chemically inert aggregate.
• the roots of macrophytes rooted in the aggregate allow them to filter the water and thus retain some of the suspended matter they contain. Macrophytes also contribute to the reduction of nitrogenous and phosphorous organic matter present in these waters.
• An important feature of the process lies in the dilution of the water to be treated with water constituted at least in part by treated water. According to the invention, this dilution must be carried out according to a ratio of the volume of dilution water to the volume of waste water of between 8 and 50 and preferably between 10 and 20.
• Such a dilution according to such a ratio makes it possible to bring to the bio-reactor dilute water little loaded with suspended matter and organic matter, and thus to avoid the clogging of the bed of aggregate and consequently to ensure good aeration of the roots. macrophytes.
• This dilution step can be carried out with only treated water, or again partly with treated water and partly with make-up water such as rain water.
• Another important feature of the process according to the invention lies in the mode of feeding and emptying of the bio-reactor according to tidal cycles.
• Such tidal cycles allow a forced aeration of the aggregate bed with the oxygen of the air present around the aggregates when the water withdraws from it, aeration which promotes the action of microorganisms and therefore the purification of the water.
• Such cycles thus make it possible to arrange aerobic and anoxic phases within the aggregate bed favorable to the degradation of nitrogen pollution in water.
• each of these cycles (feed + drain) must last less than 2 hours, preferably less than 1 hour.
• the bed will be ventilated for 30% to 50% of the duration thereof.
• the method according to the invention has the advantage of not using aerators.
• the method is therefore less expensive than the methods of the prior art using such equipment.
• said process can be supplemented by at least one adsorption step consisting in passing the water drained from said bioreactor over a bed of adsorbent material, and / or by at least one membrane filtration step. consisting of passing the water drained from said bio-reactor or the water coming from said adsorption step over filtration membranes, such as low pressure microfiltration and / or ultrafiltration membranes and / or nanofiltration membranes and / or reverse osmosis membranes.
• filtration membranes such as low pressure microfiltration and / or ultrafiltration membranes and / or nanofiltration membranes and / or reverse osmosis membranes.
• the method comprises a stage of dilaceration of the compacted organic matter contained in the water, said dilaceration stage being carried out before, during or after said preliminary dilution stage.
• the purpose of such a shredding step is to break down the compacted organic matter (such as faeces) present, if applicable, in the urban wastewater to be treated and therefore to bring more homogeneous water into the bio-reactor that is less likely to clog. the bed of chemically inert aggregate.
• the method comprises a final step of disinfecting the water coming from said at least one filtration step.
• the objective of such disinfection is to obtain, at the end of the process, water of sufficient quality to allow its reuse.
• different ways of organizing the supply and the emptying of the latter can be envisaged.
• the supply of said bio-reactor is clocked and the emptying of the latter is continuous.
• timed feed is understood to mean the fact that the feed to the reactor with dilute water is not carried out with a constant flow rate during the tidal cycle. Thus, for example, the feed can be carried out first at a given rate and then stopped.
• the supply of said bioreactor is continuous and the emptying of said bioreactor is timed.
• timed emptying is understood to mean the fact that the emptying of the reactor is not carried out at a constant rate during the tidal cycle. Thus, for example, the emptying can be carried out first at a given flow rate and then stopped.
• the process according to the invention will preferably be carried out by keeping an upper zone of the bed of chemically inert aggregate dry, the supply of the bioreactor with dilute water being carried out under said zone. superior.
• a dry zone makes it possible to further reduce the risk of the appearance of bad odors and of larval organisms such as mosquitoes.
• the dilution step is carried out using water originating from said bioreactor and / or from said adsorption step and / or from said membrane filtration step.
• the invention also relates to an installation for the biological treatment of wastewater with the method described above, characterized in that it comprises a dilution tank, a bio-reactor comprising a basin accommodating a bed of chemically inert aggregate and macrophytes emerged rooted in said aggregate, means for feeding said bio-reactor from the dilution tank and means for emptying said bio-reactor according to tidal cycles, and means for conveying part of the treated water to said dilution tank.
• the term “dilution tank” is understood to mean a simple tank making it possible to carry out a dilution.
• said chemically inert aggregate forming the bed of the bioreactor consists of beads having an average diameter of between 5 mm and 50 mm and preferably between 5 and 10 mm.
• Such a size of beads optimizes the volume of air that can be lodged in the interstices separating them and facilitates the emptying of the bio- reactor.
• said balls are balls of expanded clay. This material has the advantage of being light, of retaining its properties over time, and of having a very high specific surface on which such a large surface of biofilm can form, allowing the purification of water.
• the installation preferably further comprises an adsorption unit on an adsorbent material such as activated carbon supplied with water coming from said bioreactor and / or at least one membrane filtration unit for water coming from said bioreactor. of said bioreactor or of said adsorption unit.
• an adsorption unit on an adsorbent material such as activated carbon supplied with water coming from said bioreactor and / or at least one membrane filtration unit for water coming from said bioreactor. of said bioreactor or of said adsorption unit.
• Such equipment makes it possible to further reduce the content of organic matter and suspended matter in the treated water.
• the installation further comprises means for shredding compact organic matter such as faeces which may be contained in said waste water.
• such means could be constituted by a macerator pump.
• the destructuring of the compact organic materials made possible by such means leads to obtaining wastewater that is more homogeneous and therefore less likely to block the interstices existing between the granulate balls.
• the installation further comprises at least one unit for disinfecting the filtered water coming from said at least one filtration unit.
• Such a unit makes it possible to obtain water of sufficient bacteriological quality to allow its reuse as water for human consumption, in particular as drinking water. It is also possible to envisage the reuse of such water for watering gardens or else for supplying devices leading to gray water such as washing machines or dishwashers.
• said means for supplying said bioreactor comprise a supply line provided with a valve and said means for emptying said bioreactor comprise an evacuation line provided in the lower part of the bioreactor.
• said means for supplying said bioreactor comprise a supply line and said means for emptying said bioreactor comprise an evacuation line provided with a pump provided in the lower part of said bioreactor.
• the bio-reactor of the installation according to the invention is provided on the roof of a building, the macrophytes emerging from the latter then forming a green cover of said building.
• the green roof technique can make it possible on a large scale to reduce the negative impacts linked to climate change. On a city scale, it improves air quality, regulates temperature, and also optimizes rainwater management. It also eliminates the need for irrigation and the supply of nutrients to the vegetation, saves energy costs and provides acoustic insulation for buildings.
• Figure 1 is a sectional view of an embodiment of a bioreactor that can be used in the context of an installation according to the invention.
• FIG. 2 is a diagram of an installation according to the invention incorporating such a bioreactor.
• a bioreactor 4 comprises a basin 10 having a depth which may be between 20 cm and 1 m and preferably between 30 cm and 50 cm.
• a layer of draining gravel 11 can be placed in the bottom of this basin 10 over a height of between 0 and 10 cm.
• the bio-reactor 4 comprises a bed 12 of chemically inert mineral aggregate, here expanded clay balls having a diameter of 5 mm to 10 mm, provided above the layer of gravel over a height of between 20 and 90 cm .
• Emerged macrophytes 13 are rooted in said bed 12 of aggregate.
• Means 14 for supplying the bio-reactor 4 with water comprise a simple pipe 14a opening into the bed 12 of aggregate at a distance of approximately 3 cm to 5 cm below the surface 12a thereof so as to provide a zone hair 12b across the top of it.
• Means 15 for emptying the bioreactor 4 for their part comprise a pipe 15a allowing the evacuation of the treated water by gravity.
• the installation according to the invention comprises a dilution tank 1 capable of receiving on the one hand waste water by means of supply means 2 comprising a pipe provided with a macerator pump 2a and d '' on the other hand the dilution water via a recycling pipe B.
• the installation furthermore comprises the bio-reactor 4 described above with reference to FIG. 1, and a pipe allowing it to bring the water coming from the dilution tank 1 into the latter.
• the installation also comprises an adsorption unit 5 comprising a bed of granular activated carbon, and a pipe 4a making it possible to bring the water coming from the bioreactor 4 into the latter.
• the installation also includes a chlorination or ozonation unit 6 provided downstream of the adsorption unit 5 and a pipe 5a provided with a pump (not shown) for conveying the filtered water from unit 5 to that -this.
• the installation also comprises a first membrane filtration unit 7 comprising low pressure microfiltration and / or ultrafiltration membranes and a pipe 6a provided with a pump (not shown) for conveying the chlorinated or ozonated water in the unit 6. to this one.
• the installation also includes a second membrane filtration unit 8 comprising high pressure nanofiltration and / or reverse osmosis membranes and a pipe 7a provided with a pump (not shown) for conveying the water coming from the first filtration unit. membranes 7 in the second membrane filtration unit 8 towards it.
• the installation also includes a disinfection unit 9 provided downstream of the reverse osmosis stage 8 and a pipe 8a provided with a pump (not shown) for conveying the water filtered through a membrane into the low membrane filtration unit. press 7 towards it.
• the installation comprises a pipe 9a for discharging treated water.
• the pipe S for supplying the tank 1 with dilution water may be connected either to the pipe 4a, or to the pipe 5a, or to the pipe 6a, or to the pipe 7a.
• a level probe lb slaved to a set of automatic valves (not shown) is provided in the dilution tank 1 to control the dilution of the wastewater by the dilution water conveyed through the pipe B. Thanks to this level probe lb , the. water drained from the bioreactor 4, from the adsorption unit 5, or from the oxidation unit 6, or from the low pressure filtration unit 7 are directed into the dilution tank 1 when the water level in the dilution tank 1 detected by this probe is below a predetermined level. The treated water is directed to the units considered when the water level in the dilution tank 1 is greater than or equal to this predetermined level.
• the wastewater conveyed by the macerator pump 2a, and whose compacted organic matter (faeces) have been destructured by the action thereof, are diluted in the dilution tank with l dilution water according to a ratio of the volume of dilution water to the volume of wastewater between 8 and 50 and preferably between between 10 and 20.
• the diluted water is conveyed from the dilution tank 1 and admitted by the means 14 into the basin 10 of the bioreactor 4 below the dry zone 12b of the bed 12 of granulate beads.
• the pump 15b of the emptying means is not actuated.
• the water gradually rises in the bed 12.
• the pump 15b of the emptying means is, after a predetermined time, actuated to empty the basin 10 faster than it fills.
• the bed 12 is thus irrigated and then exposed to the air according to a tidal cycle the total duration of which is less than 2 hours, preferably less than one hour.
• Such a cycle makes it possible to ensure forced aeration of the bed of clay balls and the bringing into contact of the microorganisms contained in this bed with the oxygen contained in the air.
• the pump 15b can again be stopped and another tidal cycle started.
• the basin is therefore fed and emptied according to a repeating tidal cycle.
• this cycle lasts less than two hours, preferably less than an hour.
• the bed is depleted for a period representing 30% to 50% of the total duration of the cycle.
• each cycle having a duration of less than two hours, preferably one hour the bed is never in an anaerobic condition. The development of anaerobic biomass which generates bad odors is thus prevented.
• the water passing through the reactor is thus filtered by the roots and rhizomes of the macrophytes and biologically purified mainly by the microorganisms developing in bed 12.
• the water coming from the bioreactor 4 is then conveyed by line 4a to the upper part of the filtration unit 5 containing a bed of powdered activated carbon and passes through the latter before being recovered in its lower part.
• This passage adsorbs dissolved organic matter and micropollutants that may be present in the water coming from the bioreactor 4.
• the water coming from the activated carbon filtration unit 5 is then conveyed to the unit 6 via the pipe 5a where it undergoes oxidation.
• the object of this oxidation is to prevent the clogging of the membranes used in the low pressure membrane filtration unit 7 to which the water is conveyed from the oxidation unit 6 via the pipe 6a.
• the filtered water coming from the low pressure membrane filtration unit 7 is then routed through line 7a into the high pressure membrane filtration unit (nanofiltration and / or reverse osmosis) 8.
• the filtered water coming from the high pressure membrane filtration unit 8 is then conveyed through the pipe 8a to the final disinfection unit.
• the disinfected water is evacuated through line 9a.
• This water is of sufficient quality to allow its use, for example for the operation of flushing water or supply water for washing machines or washing machines. dishes, or even for use as drinking water when regulatory provisions allow.
• the process was tested with wastewater having the following composition: a suspended solids content (SS) of between S00 and 1000 mg / L, a COD (chemical oxygen demand) of between 200 and 500 mg O2 / L, an organic nitrogen content (NTK) of between 8 and 35 mg / L, and a total phosphorus content of 1 to 5 mg / L.
• SS suspended solids content
• COD chemical oxygen demand
• NNK organic nitrogen content
• the bioreactor used may correspond to that shown in FIG. 1 but with the modifications consisting in removing the pump 15b from the emptying means and in providing a supply valve on the pipe. 14a means for supplying diluted water.
• the repetition of the tidal cycles will be created by intermittently closing this supply valve.
• the basin of the bio-reactor will be able to empty and the bed of aggregate will thus be aerated.
• the feed valve is reopened, the aggregate bed will again be submerged.

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• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Biological Treatment Of Waste Water (AREA)
• Separation Using Semi-Permeable Membranes (AREA)

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• 2020
  • 2020-02-10 FR FR2001319A patent/FR3107054B1/fr active Active
• 2021
  • 2021-02-10 EP EP21704515.2A patent/EP4103521A1/de active Pending
  • 2021-02-10 WO PCT/EP2021/053149 patent/WO2021160644A1/fr not_active Ceased

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