Classifications

• • 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
  • C02F3/28—Anaerobic digestion processes
  • C02F3/2846—Anaerobic digestion processes using upflow anaerobic sludge blanket [UASB] reactors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
  • B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
  • B01D53/047—Pressure swing adsorption
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
  • B01D53/26—Drying gases or vapours
  • B01D53/265—Drying gases or vapours by refrigeration (condensation)
• • 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
  • C02F3/006—Regulation methods for biological 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
  • C02F3/28—Anaerobic digestion processes
  • C02F3/2866—Particular arrangements for anaerobic reactors
  • C02F3/2873—Particular arrangements for anaerobic reactors with internal draft tube circulation
• • 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
  • C02F3/28—Anaerobic digestion processes
  • C02F3/2866—Particular arrangements for anaerobic reactors
  • C02F3/2893—Particular arrangements for anaerobic reactors with biogas recycling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/102—Carbon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
  • B01D2253/10—Inorganic adsorbents
  • B01D2253/106—Silica or silicates
  • B01D2253/108—Zeolites
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/30—Sulfur compounds
  • B01D2257/304—Hydrogen sulfide
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2257/00—Components to be removed
  • B01D2257/80—Water
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2258/00—Sources of waste gases
  • B01D2258/05—Biogas
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2201/00—Apparatus for treatment of water, waste water or sewage
  • C02F2201/002—Construction details of the apparatus
  • C02F2201/005—Valves
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2203/00—Apparatus and plants for the biological treatment of water, waste water or sewage
  • C02F2203/002—Apparatus and plants for the biological treatment of water, waste water or sewage comprising an initial buffer container
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2209/00—Controlling or monitoring parameters in water treatment
  • C02F2209/03—Pressure
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2209/00—Controlling or monitoring parameters in water treatment
  • C02F2209/42—Liquid level
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2301/00—General aspects of water treatment
  • C02F2301/04—Flow arrangements
  • C02F2301/046—Recirculation with an external loop
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2301/00—General aspects of water treatment
  • C02F2301/06—Pressure conditions
  • C02F2301/063—Underpressure, vacuum

Definitions

• the present invention relates to a device for purifying waste water and a process for purifying waste water. It applies, for example, to the field of urban wastewater treatment. State of the art
• ERU treated urban waste water
• Biomass retention in sludge bed reactors is based on the ability of anaerobic microorganisms to flocculate to form granules which can reach up to 5 mm in diameter and which exhibit good sedimentation characteristics (volume index ⁇ 20 mL .gMVS' 1 ; maximum sedimentation rate > 5 mh 1 ), and good mechanical resistance. This prevents them from being washed out of the reactor, in which the upward velocity of the liquid is generally maintained between 1 and 1.5 m.h' 1 .
• Granulation is a slow process which leads to a long start-up period (about six months) if unsuitable digester sludge is used as inoculum.
• the formation of a granular sludge is practically impossible with certain types of effluents and degranulation can be observed when the reactor which treats these effluents is seeded with an already granular sludge.
• Sludge bed processes are also sensitive to the SS concentration of the effluent. Indeed, a low ascent rate does not allow the leaching of particulate matter, which can cause their accumulation at the expense of the formation of granules, thus leading to a decrease in biological activity.
• the resolution of these problems requires a better knowledge of the intimate mechanisms of granulation and the factors that govern it.
• the granules consist exclusively of microorganisms. It is generally accepted that their formation is the result of the selection of flocculant bacteria in an upward flow system where the free cells in suspension are necessarily leached out.
• the granules also have a very complex bacterial organization. Fermentative, syntrophic and methanogenic microorganisms are closely associated with each other, which reduces the distance between them. The inter-species transfer of hydrogen and the diffusion of metabolites along the trophic chain are more efficient.
• HRT hydraulic residence time
• TRS sludge residence time
• EGSB for “Expanded Granular Sludge Bed”, translated by “extended granular sludge bed”
• the EGSB combines the recirculation of the effluent with upward speeds greater than 4m. IT 1 and taller reactor geometries (high height/diameter ratio).
• the compartmentalization of the reactor space has led to the internal circulation reactor (IC for “Internai Circulation”, translated as “internal circulation”), which consists of two stacked UASB reactors.
• IC Internal Circulation
• the lower reactor operates at high load and the biogas produced is recovered for the fluidization of the second reactor, by gas-lift effect, located above and fed at low load.
• ERUs are considered as dilute effluents (COD ⁇ 1000 mg.L 1 ), they have the characteristics of a complex effluent, with a low temperature (oscillating between 15 and 25°C) and a high ratio of suspended solids d 50-65%, ie a low ratio of soluble COD to total COD. Consequently, the total conversion of the COD is limited by the phase of hydrolysis of the solid compounds.
• the management and yields of this biogas technology are highly dependent on temperature. Like all chemical and biochemical transformations, the speed reactions that occur in methanization increase with temperature. However, these systems are very dependent on their operating temperature.
• US patent application 2020 392 025 and US patent 8 721 877 are known, which disclose devices for treating waste water solids and gases.
• such devices operate under atmospheric pressure and therefore do not make it possible to promote the evaporation of the biogas partially dissolved in the treated water and therefore an optimal recovery of the biogas.
• such devices do not make it possible to obtain treated water with an optimized COD value and in particular associated with a reduced concentration of residual pollutants.
• the treated water obtained by these devices still has a large quantity of floating material, this treated water therefore does not have a good quality making it possible in particular to satisfy the prescribed specifications.
• the present invention aims to remedy all or part of these drawbacks.
• the present invention relates to a purification device according to claim 1.
• the saturation pressure is preferably below atmospheric pressure (the dissolution constant of a gas is proportional to the pressure in the enclosure), and
• a buffer column makes it possible in particular to optimize the operation of the digester. Indeed, such a buffer column allows the start of a flow of wastewater to the digester according to hydrodynamic constraints imposed by the digestion process. In particular, such a flow, or hydraulic circulation, is caused according to the principle of communicating vessel when a depression is applied in the upper part of the digester. Furthermore, the buffer column and the flow it causes during the implementation of the digestion process carried out by the digester, contributes to the application of a sufficient vacuum and in particular a negative pressure in the upper part of the digester and above the supernatant water.
• the digester comprises a low treated water outlet connected to the weir and positioned at a third height from the lower part, said third height being less than the first weir height.
• the treated water outlet is arranged at the bottom of the digester, the evacuation of treated water is possible without suction of air through this treated water outlet. In this case, such an evacuation is carried out despite a negative pressure, or depression, applied in the upper part of the digester.
• the third height of the treated water outlet is less than or equal to the level of wastewater present in the buffer column. Thanks to these provisions, the evacuation of treated water is carried out easily, for example, in the lower part of the digester. In particular, such an evacuation is optimized by the hydraulic pressures generated in the device.
• the treated water outlet further comprises a valve for extracting water from the weir. Thanks to these provisions, the evacuation of treated water is carried out when the extraction valve is opened.
• an adjustable flow rate of treated water is generated in particular according to the constraints of wastewater treatment, such as the volume of this wastewater to be treated or the volume of treated water to be generated.
• the device that is the subject of the invention comprises a sensor for the presence of water in the weir, at least the extraction valve being activated according to the presence of water collected.
• the device that is the subject of the invention further comprises:
• biogas recirculation pipe from the biogas outlet to the biogas inlet.
• the device that is the subject of the invention further comprises a valve for activating the recirculation pipe.
• a valve for extracting water from the weir allow the device to have distinct modes of operation depending on the opening and closing of the valves.
• the device that is the subject of the invention has a mode of operation in which the recirculation pipe activation valve and the water extraction valve are closed.
• the device that is the subject of the invention further comprises:
• a pressure sensor configured to capture an operating pressure in the upper part of the digester
• a proportional, integral, derivative regulator configured to regulate the operation of the vacuum pump according to the pressure sensed in the upper part of the digester.
• the digester further comprises an open reservoir, the column for raising water by suction of water biogas comprising, in the upper part of the digester, an outlet for raised biogas, said outlet being connected to the tank open and positioned at a fourth height lower than the first height.
• the biogas rise column is at least partially surrounded by a settling zone.
• a fifth height defining the limit of the settling zone is lower than the first height of the weir. Thanks to this arrangement, the settling zone makes it possible to limit the quantity of particles in suspension, in particular floating particles, from reaching the first height of the treated water overflow. The COD of the treated water is therefore reduced. Thus, the quality of treated water is improved.
• the settling zone comprises a lamellar settling tank. Thanks to this arrangement, the settling zone makes it possible to further limit the quantity of polluting particles in suspension in the treated water. Settling is therefore optimized, thus improving the quality of the treated water.
• the digester further comprises a gas-liquid-solid separator communicating with a lower end of the rising water column, the separator being substantially conical of revolution and of apex disposed inside the rising water column and being configured to convey at least biogas into the rising water column. Thanks to these provisions, the separator allows the orientation of biogas and water towards the rising water column while limiting the rising of solid particles.
• the conical separator has a base and the digester further comprises a deflector:
• the deflector allows an accumulation of biogas on a lower portion then a direction of the flow of biogas towards the separator.
• the excess biogas not retained by the lower portion rises towards the base of the separator while being guided by the end of the deflector and is then routed towards the column of rising water to carry out a rise of water by entrainment gas also called the “gaslift” effect.
• the cooperation between the separator and the deflector therefore allows an optimized gaslift effect.
• the homogenization of the mixture present in the digester is optimal.
• the device that is the subject of the invention comprises:
• a "PID" type regulation can be set implemented, in which the operating frequency of the pump is slaved to the liquid level of the buffer column.
• the device that is the subject of the invention comprises, downstream of the vacuum pump:
• the digester includes:
• thermal enclosure configured to receive a flow of hot water, comprising an inlet for water and an outlet for water,
• a heat exchanger configured to heat or cool the hot water, the water leaving the heat exchanger being supplied to the water inlet of the enclosure.
• the present invention relates to a process for purifying wastewater according to claim 19.
• FIG. 1 represents, schematically, a particular embodiment of the device which is the subject of the invention
• Figure 2 schematically represents the device shown in Figure 1, upstream of the start-up of such a device
• FIG. 3 represents, schematically, the device represented in FIG. 1, during the implementation of such a device
• FIG. 4 represents, schematically and in the form of a flow chart, a succession of steps of a mode particular embodiment of the method which is the subject of the invention.
• valve designates any type of valve known and suitable for the contextually indicated use.
• a valve is, for example, a motorized valve.
• FIG. 1 A schematic view of an embodiment of the device 100 object of the invention is observed in FIG. 1, which is not to scale.
• This wastewater treatment device 100 comprises a vacuum anaerobic digester 105 comprising:
• weir 125 for treated water comprising an outlet 130 for water positioned according to a first height 131 from the lower part
• An outlet 135 for biogas positioned at a second height 136 greater than the first height.
• the device 100 also comprises:
• a vacuum pump 145 connected to the biogas outlet configured to, when said pump is activated, cause water to flow from the lower part to the upper part.
• the anaerobic digester 105 refers to a tank used in the methanization process which produces biogas through an anaerobic digestion process of organic matter from various sources.
• the organic matter preferably comes from urban waste water.
• the digester 105 is said to be "vacuum”, that is to say that its preferred operating conditions are at a pressure generally lower than atmospheric pressure.
• the digester 105 is formally divided into two parts: a lower part 110 and an upper part 120 whose relative proportions can vary.
• the part of the digester 105 generally close to the base, that is to say the ground, when the digester 105 is in operating condition, is generally called the “lower part 110”.
• the lower part 110 thus designates the place of reception of the gravity flows occurring within the digester 105.
• This digester 105 can implement various internal devices capable of interacting with the flow flows of biogas, water and/or or organic waste.
• the digester 105 can implement, as visible in FIG. 1, a flow device with grooves or fins configured to distribute the flows evenly in the lower part 110.
• Such devices make it possible to avoid the accumulation of sludge in a particular place of the digester 105 likely to deactivate it or at least to reduce its yield.
• the digester 105 comprises an inlet 115 for waste water.
• Such an inlet 115 corresponds to an opening, preferably connected to a pipe, and optionally associated with means for controlling a valve governing the opening and/or closing of the inlet.
• a valve can be actuated manually or automatically, using an automaton, depending on preferential operating values of the digester 105.
• the lower part 110 of the digester 105 also comprises a bed of microorganisms, such as bacteria , selected for their ability to digest ERUs and produce biogas. In particular, such digestion carried out by bacteria is carried out without oxygen and thus corresponds to anaerobic digestion.
• microorganisms can be supported by granules 121, for example so-called “UASB” bacterial granules, placed at the bottom of the tank (that is to say in the lower part 110) of the digester 105.
• a generation of a bed of bacteria present in a digester 105 is carried out according to a method known to those skilled in the art, for example by introducing bacteria into the digester 105 also called inoculation of the digester, or by introducing waste to be treated progressively presenting bacteria which will, over time, create UASB granules.
• the wastewater thus presents an upward flow in the transverse surface of the reactor, except in column 141 where the water descends.
• the lower part 110 and the upper part 120 of the digester 105 are connected by a column 140 for rising water by suction of the biogas from the lower part 110 to the upper part 120.
• the lower part 110 and the upper part 120 of the digester 105 are also connected by a column 141 for lowering untreated waste water from the upper part to the lower part.
• Columns 140 for rising water by suction of biogas and 141 for lowering water are, for example, coaxial.
• the digester 105 comprises a means of collecting wastewater raised by the suction action of the biogas through the column 140 of rise. This waste water is then directed to the column 141 for the descent of the waste water to the lower part of the digester 105.
• the water in the lower part 110 is sucked up to the upper part of the digester 105.
• the columns 140 of rise and 141 of descent amplify the mixing within the reactor by channeling towards the biogas center.
• the digester 105 mainly comprises outlets for the different species of interest generated.
• an outlet 130 for water supplied by a weir 125 whose function is to allow the outlet of water exceeding a predetermined height, called first height 131, function of the level of depression, which is fixed according to the height of the reactor, chosen to correspond to the height reached by the water once treated by the microorganisms.
• outlet of the weir 125 is used, for example, a liquid retention wall whose crossing constitutes the outlet 130, analogously to the operation of a hydraulic weir.
• the term "height" refers to a value of a physical quantity representative of the distance between the base and a given point of the digester 105 along a gravitational vertical axis.
• the height can also be measured from the highest point of the tank or any other reference point located at a higher altitude than the point of interest whose height is measured when the digester 105 is in working conditions. operations.
• the weir 125 is connected to a pipe for the vertical flow of the treated water towards the lower part 110, by gravity or by means of a pump, so as to counterbalance the effect of the negative pressure in upper part 120 of the digester 105 when the water leaves the digester 105.
• the digester 105 comprises a low outlet 300 for treated water connected to the weir 125.
• an outlet base 300 of treated water is positioned at a third height 301 from the lower part, the third height 301 being preferably lower than the first height 131 of the weir 125.
• the third height 301 of the low outlet 300 of treated water is less than or equal to the level of waste water 302 present in a buffer column 190.
• the column buffer 190 contains waste water, the surface of this waste water being at a height 302 being equal at least to a third height 301 of outlet 300 of treated water.
• the third height 301 of the low outlet 300 of treated water is lower than the level of waste water 302 present in a buffer column 190.
• the device 100 represented in FIG. 3 corresponds to an operating mode of the digester 105 when the anaerobic digestion is implemented.
• the pressure applied in the upper part and above the supernatant water is negative, for example equal to -0.5 bar.
• this mode of operation shown in Figure 3 it is noted that, for example, the water flows into the weir 125 and therefore has a level according to a first height 131.
• a low outlet 300 for treated water further comprises a valve 165 for extracting water from the weir 125.
• a valve 165 extraction is a motorized valve.
• the water extraction valve 165 is coupled to a water extraction pump.
• the water extraction valve 165 is open in order to ensure the evacuation of the treated water.
• such an opening is made following a command sent by a water presence sensor in the weir 125.
• the hydrostatic pressure value will be greater than the depression value and the flow of treated water will take place without suction of outside air.
• the outlet 130 for water from the weir 125 such as a pipe 130 connected to the weir 125 is filled with water
• such filling corresponds to a hydraulic seal and avoids the suction of air that can occur when the valve 165 water extraction is open.
• the device 100 comprises a sensor 170 of the presence of water in the weir 125, at least the extraction valve 165 being activated depending on the presence of water captured .
• the sensor 170 is, for example, a capacitive sensor activated by the presence of water in the weir 125.
• the detection of water can correspond to a change in the operating regime of the device 100, from a power increase phase to a nominal operating phase. These regime changes are described below.
• the digester 105 comprises an outlet 135 for biogas, comprising for example a biogas extraction pipe, one opening of which is positioned at the second height.
• the exit 135 is configured to suck the biogas located above the purified water and the water sucked by the column 141 of descent.
• the movement of water in the digester 105 is caused by the action of the vacuum pump 145 configured to generate a depression, at the level of the outlet 135 for biogas, lower than the inlet pressure of the ERUs in the digester 105.
• the device 100 comprises:
• biogas recirculation pipe 155 from the biogas outlet 135 to the biogas inlet 150.
• Inlet 150 is, for example, structurally similar to inlet 115 for waste water in the different variants shown.
• the recirculation pipe 155 is, for example, a pipe configured to connect the downstream of the vacuum pump 145 and the inlet 150 for biogas in the lower part 110 of the digester 105.
• This recirculation pipe 155 can be associated with a set valves whose selective actuation makes it possible to force all or part of the flow of biogas towards said conduit 155 for recirculation.
• the vacuum pump 145 is connected to a biogas evacuation pipe and the recirculation pipe 155 is a tapping on this evacuation pipe, the tapping and the evacuation pipe each being associated with a valve. separate whose opposite activation causes the passage of biogas either in the discharge pipe or in the pipe 155 of recirculation.
• the recirculation line 155 is associated with a gas pump and/or a non-return valve upstream of the inlet 155.
• the device 100 further comprises a valve 160 for activating the pipe 155 of recirculation.
• a valve 160 for activating the pipe 155 of recirculation.
• An exemplary embodiment of the activation valve 160 is shown above while the valve 165, functionally, allows the extraction of water from the weir 125, that is to say that as long as the valve 165 d extraction is closed, the water captured by the weir 125 remains in the same pressure environment as the rest of the digester 105.
• the water leaving the weir can be valued in many ways.
• the device 100 has a mode of operation in which the valve 160 for activating the pipe 155 of recirculation and the valve 165 of water extraction are closed.
• Such an operating mode corresponds to a power-up or initialization phase of the device 100 in which the vacuum is created in the digester 105.
• the outlets and inlets of the digester 105 must be in the closed position. .
• the water is raised along the digester 105, from the lower part 110 to the upper part 120 and this until treated water enters the weir 125.
• a valve 165 is opened, allowing the exit of the treated water.
• Other operating modes are described below.
• the device 100 further comprises: - a pressure sensor 175, configured to sense an operating pressure in the upper part 120 of the digester 105, and
• a PID regulator 180 configured to regulate the operation of the vacuum pump 145 according to the pressure sensed in the upper part of the digester 105.
• the pressure sensor 175 can be of any type known to a person skilled in the art which corresponds to the operating conditions of the device 100 in particular in terms of temperature, pressure or humidity.
• the PID 180 regulator for "proportional, integral, derivative” is a control system that improves the performance of a servo, i.e. a closed loop system or process.
• the vacuum pump 145 is controlled by the pressure detected by the sensor 175.
• the digester 105 further comprises an open reservoir 303.
• a reservoir is said to be "open” since it has an at least partial opening communicating with the upper part of the digester 105 in which is applied a negative pressure also called depression.
• the pressure inside the open tank 303 is equal to the depression applied by the vacuum pump 145 in the upper part of the tank and in particular above the supernatant water. . It is noted that such a tank is connected to the column 140 of water rise 140.
• the column 140 for raising water by suction of the biogas 304 comprises, in the upper part 120 of the digester 105, an outlet 185 for raised biogas 304, the output being:
• This height differential is due to the gaseous retention rate in the area above the column 140 of rising water by suction of the biogas.
• outlet 135 for biogas is located at a higher altitude than outlet 130 for water from weir 125,
• Outlet 185 for water from column 140 is located at a lower altitude than outlet 130 for water from the spillway and at a lower altitude than outlet 135 for biogas.
• the liquid level in this sector, and in particular inside the open tank 303, is higher by the “gaslift” effect, that is to say by the rise of the biogas carrying waste water. This liquid level is shown with a second striped line 187.
• column 140 allows the rise, by gaslift effect, of water with biogas corresponding to a two-phase gas/liquid mixture.
• outlet 185 for water from column 140 inside open tank 303 the two-phase mixture will settle:
• the water will go down in the column 141 of untreated waste water descents, such as a pipe, having an outlet towards the zone of the sludge bed to optimize mixing.
• a biogas rise column 140 is at least partially surrounded by a settling zone 305.
• a settling zone 305 is also called a clarification zone.
• a fifth height 306 defines the limit of the settling zone 305. More preferably, the fifth height 306 is lower than the first height 131 of the weir 125. It is noted that such a settling zone makes it possible to promote the settling and therefore the separation of the floating materials and suspended solids in the water.
• the settling zone 305 comprises a lamellar settling tank.
• a lamellar settling tank has plates arranged in parallel in order to increase the settling surface.
• the lamellae are arranged obliquely so as to guide the sliding of the sedimented materials and the floating materials towards the bottom of the lamellar settling tank.
• the digester 105 of the device 100 further comprises a gas-liquid-solid separator 307 communicating with a lower end of the column 140 for raising waters.
• the separator 307 is substantially conical of revolution and has a vertex arranged inside the column 140 of rising water. It is noted that such a separator 307 is configured to convey at least biogas to achieve the gaslift effect in the rising column 140 of water.
• the conical separator 307 has a base 310 represented by a dotted circle.
• the digester 105 further comprises a deflector 308:
• part of the water initially present in the lower part of the digester 105 circulates towards the settling zone 305 passing between the space delimited by the base 310 of the separator 307 and the end of the deflector 308.
• the device 100 comprises a buffer column 190 configured to receive waste water, said buffer column comprising:
• the inlet 115 for waste water from the digester 105 being connected to the buffer column 190 and configured to supply waste water by depression.
• the main function of the buffer column 190 is to act as a reservoir from which, by suction, water to be treated is drawn towards the digester 105.
• the inlet 195 is, for example, analogous to the inlet 115 of the digester 105.
• the intake 200 d Atmospheric air is, for example, an opening to the environment outside the device 100, optionally capable of being closed or not by means of a valve or a valve.
• the inlet 115 for waste water can be reduced to a pipe that is not blocked or can be closed between the digester 105 and the buffer column 190.
• the device 100 comprises:
• the sensor 205 is, for example, an ultrasound sensor.
• the pump 210 is for example configured to inject waste water into the 190 buffer column.
• the pump 210 is for example configured sewage injection disposal.
• the device 100 comprises, downstream of the vacuum pump 145:
• an adsorption means 220 to purify the biogas and/or
• the dehumidifier 215 is, for example, a condenser of residual water vapors present in the biogas.
• the adsorption means 220 is, for example, an activated carbon adsorption column or another porous adsorption medium such as silica or zeolites. In variants, the adsorption means 220 can also be more complex if the quality of biogas required at the outlet must be higher, for example of the "PSA" type (for "Pressure Swing Adsorption", translated by adsorption by pressure inversion) .
• the storage 225 may correspond to a transport pipe or to a tank, for example.
• the device 100 further comprises:
• the digester 105 includes:
• thermal enclosure 230 configured to receive a flow of hot water, comprising an inlet 235 for water and a hydraulic gasometer protection guard 225,
• a hot water circuit 245 comprising:
• a water pump 250 connected to the outlet 240 for water from the enclosure 230 and
• a heat exchanger 255 configured to heat or cool the hot water, the water leaving the heat exchanger 255 being supplied to the water inlet 235 of the enclosure 230.
• a valve 165 for the treated water outlet of the digester 105 is closed to prevent atmospheric air from being sucked inside the digester 105, making it impossible to prime the device 100,
• the digester 105 is six meters high, i.e. a pressure of 500 mbarA (-0.5 barG),
• the treated water is discharged because the stream is located in a zone of positive pressure; the liquid level of the buffer column 190 and the outlet are balanced according to the water flow at the inlet 115,
• the system operates stably; the treated water leaves the digester 105 through a dedicated outlet 130 and a circulation loop inside the digester 105 is created by the effect of the rise of the biogas amplified by the vacuum; the gas retention rate increases with the level of depression,
• the biogas produced is extracted by the vacuum pump 145 and goes through a step to eliminate pollutants that can be absorbed in the vacuum network (foam and scum) via a condensate tank,
• the biogas then goes through a dehumidification stage; the condensates are removed by gravity,
• the biogas then passes through a means of adsorption with extruded activated carbon or any other adsorbent material to eliminate the H2S species,
• the biogas is stored in a double-membrane gas holder (30 mbarsG) until it is used; a 50 mbarG hydraulic guard 240 is associated with this device 100,
• a probe 260 for example capacitive, triggers the timed emptying procedure towards a solar dehydration zone (sludge mineralization),
• the height of the compartment is sufficient for the stored granular sludge to have a solids retention time (translated by "Solid Retention Time” and abbreviated SRT) equivalent to 30 days (psychrophilic conditions 12-25°C); this in order to ensure its correct hygienization by anaerobic digestion and
• the thermal regulation of the digester 105 is possible by the circulation of hot water in the circuit 245 and the thermal insulation.
• FIG. 2 A schematic view of an embodiment of the device 100 object of the invention is observed in FIG. 2, which is not to scale.
• the device 100 is not in operation, that is to say that the vacuum pump 145 is not activated.
• the device 100 has not yet started and no depression allowing vacuuming is exerted.
• the level of waste water in the buffer column 190 is equal to the level of waste water in the digester 105 by pressure equilibrium.
• the surfaces of the waste water present in the buffer column 190 and the digester 105 are at atmospheric pressure.
• FIG. 3 A diagrammatic view of an embodiment of the device 100 object of the invention is observed in FIG. 3, which is not to scale.
• the device 100 is in operation, that is to say that the vacuum pump 145 is activated and that a constant depression, also called negative pressure, is applied to the upper part of the digester 105.
• a constant depression also called negative pressure
• the level of waste water in the buffer column 190 is lower than the level of waste water in the digester 105.
• the surface of waste water in the buffer column 190 is at atmospheric pressure and the surface of waste water present in the digester 105 is subjected to a relative negative pressure, for example with respect to atmospheric pressure.
• a negative pressure is, for example, equal to -500 mbarG.
• This wastewater treatment process 400 includes:
• a vacuum anaerobic digestion step 405, in a digester comprising:
• step 411 for generating a bed of microorganisms in the lower part of the digester, the microorganisms comprising bacteria
• step 420 for discharging, via a spillway in the upper part of the digester, the treated water comprising a step 425 of water outlet in a water outlet of the water spillway positioned according to a first height
• step 435 of vacuum pumping connected to the outlet for biogas configured to, when said pump is actuated, cause the flow of water from the lower part to the upper part;
• the method 400 further comprises, upstream of the discharge step 420, a settling step for the separation between water and solid matter.
• a settling step for the separation between water and solid matter.

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• 2021
  • 2021-08-17 FR FR2108719A patent/FR3126226A1/fr active Pending
• 2022
  • 2022-08-16 EP EP22764799.7A patent/EP4387936A1/de active Pending
  • 2022-08-16 US US18/684,677 patent/US20240351925A1/en active Pending
  • 2022-08-16 WO PCT/EP2022/072874 patent/WO2023021042A1/fr not_active Ceased

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