Equipment for microbiological wastewater treatment

Abstract

The present invention relates to a process for the microbiological treatment of an aqueous liquid containing a biodegradable substrate in an installation comprising: (i) a bioreactor containing biomass sludge; and (ii) a biomass separator separated from the bioreactor and comprising one or more inclined plate settlers, the biomass separator having a diameter of 0.5 to 30 m. 2 and the one or more tilted plate settlers have a footprint area A of [0010] JPEG2025506003000010.jpg7170 (in the formula, psa i is the total projected surface area of ​​the inclined plate element i, m 2 The present invention relates to a process comprising a total of n inclined plate elements providing both a total projected surface area (PSA) and a total projected surface area ratio (PSAR) calculated as: PSA=PSA+PSAR≧2.8+0.17A. The equipment used to operate the process of the present invention is capable of achieving biomass separator solid-liquid separation at very high fluid flow rates without compromising separation efficiency and without substantially increasing the total footprint of the equipment. The present invention also provides equipment for the microbiological treatment of aqueous liquids containing biodegradable substrates.

Description

[Technical field]

[0001] The present invention relates to a process for the microbiological treatment of an aqueous liquid containing a biodegradable substrate in an installation comprising: (i) a bioreactor containing biomass sludge; and (ii) a biomass separator separated from the bioreactor, the biomass separator comprising one or more inclined plate settlers, the process comprising: - transferring the treated fluid containing biomass from an upper portion of the bioreactor to an upper portion of a biomass separator; Separating the treated fluid in one or more inclined plate settlers into a liquid phase having a reduced biomass content and a biomass-enriched fluid phase; Removing a liquid phase having a reduced biomass content from one or more inclined plate settlers; - returning at least a portion of the biomass-enriched fluid phase from the lower portion of the biomass separator to the bioreactor; The present invention relates to a process comprising:

[0002] The invention further relates to equipment that can be used to carry out such processes. [Background technology]

[0003] The anaerobic treatment of fluids / wastewater is typically carried out in bioreactors where (granular) anaerobic biomass converts organic pollutants into biogas, mainly consisting of methane and carbon dioxide. Typically, inside such bioreactors, devices are installed for separating the produced biogas from the treated fluid and for separating the biomass from the degassed fluid.

[0004] WO 2010 / 036107 describes a clarification device for the purification of wastewater, comprising a reaction chamber (24) containing a fermentation chamber (25) and a settling device (2) for fluids including liquids, gases and fine particulate matter, mounted above the fermentation chamber (25), said settling device: a settling chamber (3) configured to be filled with a fluid; a liquid discharge part (5) for discharging liquid from the settling chamber, the liquid discharge part (5) being arranged so as to be adjacent to the liquid level (30) during operation; a fluid inlet (6) configured to supply a fluid into the settling chamber (3) and located essentially at the same level as the liquid outlet (5); A granular material separator (7), - Sludge outlet (8) from the settling chamber (3) the inlet (6) comprises a gas separator (4) for separating gas from a fluid, the gas separator (4) comprising a row of oblique plates (13) arranged parallel to and overlapping with their longitudinal axes at an angle to the horizontal such that as fluid fed through the inlet (6) flows obliquely downward along the oblique plates, gas bubbles (34) and / or lighter particles of particulate material contained in the liquid are collected on the underside of one or more of the plates (13) and flow upward to exit the gas separator (4) at the inlet (6).

[0005] WO 2007 / 078195 describes a process for the anaerobic purification of wastewater using a sludge bed system, which comprises feeding wastewater to the bottom of an upflow reactor containing mainly granular biomass, optionally recirculating the water, and passing the resulting gas / liquid / solid mixture upwards, whereby the gas and solids are separated from the liquid in a three-phase separator, thereby producing biogas in the process producing an anaerobic effluent that is withdrawn from the top of the separator, improvements include separating the solids from the liquid in the separator, and above the separation of the gas from the liquid phase, inclined plates, tubes or other inclined internals are installed in the body of the three-phase separator to increase the effective settling surface.

[0006] WO 2012 / 005592 describes a purification device (100) for purifying wastewater, the purification device comprising: A reaction vessel (10) for a fluid, the reaction vessel (10) having a reaction chamber (11) and a bottom (12), a downer (14) having an upper end (91) and a lower end (92), the upper end of the downer being connected to the fluid collector (13) for collecting fluid from the reaction vessel (10), the downer being configured to transport the fluid towards the bottom (12) of the reaction vessel; a solids separator (20) configured to separate solids from a liquid, the solids separator (20) including a fluid inlet (72) configured to introduce a fluid into the solids separator and a liquid outlet (56) configured to remove separated liquid from the solids separator; wherein a fluid inlet of the solids separator (20) is connected to the bottom end (92) of the downer, and the solids separator is located inside the reaction vessel, at or near the bottom (12) of the reaction vessel.

[0007] The recirculation of the high fluid flow rate of the microbiologically treated fluid over the separator is beneficial for the hydraulic conditions of the bioreactor since it can be used to create better mixing and higher liquid upward flow rates in the lower part of the bioreactor, thereby preventing the accumulation of poor quality anaerobic biomass. This recirculation to the bioreactor can also be used to dilute the biodegradable substrate to a non-toxic concentration, thus creating better conditions for anaerobic fermentation.

[0008] To increase the capacity for fluid recycling, larger or additional separation devices need to be installed. Larger bioreactors, specifically those with a larger footprint area (surface area covered), may be required to accommodate these larger or additional separation devices. This results in higher capital costs and operational challenges, such as achieving good mixing between fluids and biomass in the enlarged bioreactor. To achieve the latter, even higher fluid recirculation flow rates may be required, necessitating a further increase in the size and / or number of separation devices.

[0009] It is known to place a separation device outside the bioreactor. WO 2020 / 038959 describes a method for treating an aqueous fluid containing biodegradable organic matter in an installation comprising an upflow bioreactor (1) containing a sludge bed, the sludge bed containing biomass, an external separator (2) and an equalization tank (12), Treating the aqueous fluid in the equalization tank (12) and then supplying an aqueous fluid from the equalization tank (12) to a lower portion of the bioreactor and contacting the supplied fluid with the biomass, thereby forming biogas from the biodegradable organic matter; withdrawing a fluid that has been in contact with the biomass from an upper portion of the bioreactor, the withdrawn fluid including the biomass; and - feeding the aqueous biomass-containing fluid withdrawn from the upper part of the bioreactor to an external separator (2) comprising a separation chamber provided with inclined internals, in which the aqueous biomass-containing fluid is separated into a liquid phase having a reduced biomass content or essentially free of biomass and a biomass-enriched fluid phase; - returning the biomass-enriched fluid phase from the external separator to the bioreactor; returning a portion of said liquid phase, which has a reduced content or is essentially free of biomass, from the external separator (2) to the equalization tank (12); The present invention describes a method including the steps of:

[0010] EP 1,134,194 describes a method for retaining biomass in an anaerobic sludge blanket reactor, in which a solid separator through which water from the bioreactor flows is pressurized, settling of the biomass is carried out under high pressure, and the average residence time of the water flowing through the solid separator is less than or equal to the ratio of the gas retention capacity of the water to the gas production by the biomass in the solid separator. Summary of the Invention [Means for solving the problem]

[0011] The present inventors have developed a process for treating an aqueous liquid containing a biodegradable substrate in an equipment comprising (i) a bioreactor containing biomass sludge, and (ii) a biomass separator separated from the reactor and containing one or more inclined plate settlers. The equipment used to operate the process of the present invention is capable of achieving solid-liquid separation in the biomass separator at very high fluid flow rates without compromising separation efficiency and without substantially increasing the overall footprint of the equipment.

[0012] More specifically, the inventors have described a process for the microbiological treatment of an aqueous liquid containing a biodegradable substrate in an installation comprising: (i) a bioreactor containing biomass sludge; and (ii) a biomass separator separated from the bioreactor and comprising one or more inclined plate settlers, the process comprising: Introducing an aqueous liquid containing a biodegradable substrate into a bioreactor; - transferring the treated fluid containing biomass from an upper portion of the bioreactor to an upper portion of a biomass separator; Separating the treated fluid in one or more inclined plate settlers into a liquid phase having a reduced biomass content and a biomass-enriched fluid phase; Removing a liquid phase having a reduced biomass content from one or more inclined plate settlers; transferring at least a portion of the biomass-enriched fluid phase from a lower portion of the biomass separator to a bioreactor; Contains or introducing into the bioreactor a mixture of an aqueous liquid comprising the biodegradable substrate and at least a portion of a biomass-enriched fluid phase produced by one or more inclined plate settlers, the mixture being produced by (i) introducing the aqueous liquid comprising the biodegradable substrate into a lower portion of a biomass separator and mixing said aqueous liquid with at least a portion of the biomass-enriched fluid phase, or (ii) introducing both the aqueous liquid comprising the biodegradable substrate and at least a portion of the biomass-enriched fluid phase into a mixing unit and mixing said aqueous liquid with at least a portion of the biomass-enriched fluid phase; transferring the mixture of the aqueous liquid and at least a portion of the fluid phase to a bioreactor; - transferring the treated fluid comprising biomass from an upper portion of the bioreactor to an upper portion of the biomass separator; Separating the treated fluid into a liquid phase having a reduced biomass content and a biomass-enriched fluid phase in one or more inclined plate settlers; Removing a liquid phase having a reduced biomass content from one or more inclined plate settlers. Including, Biomass separators are available in sizes from 0.5 to 30 m. 2 a footprint area A of the device or unit, the footprint area being equal to the horizontal surface area covered by a vertical projection onto the horizontal surface area of ​​the device or unit; The one or more tilted plate settlers include:

number

[0013] By using a biomass separator that is separate from the bioreactor, the processing conditions of the bioreactor and the separation conditions of the biomass separator can be optimized separately. Furthermore, efficient solid-liquid separation can be achieved at high fluid flow rates in a biomass separator with a small footprint area (relative to the footprint area of ​​the bioreactor) by ensuring that a high total projected surface area ratio (PSAR) is provided by the inclined plate settler or settlers of the biomass separator.

[0014] The present invention relates to an installation for the microbiological treatment of an aqueous liquid containing a biodegradable substrate, comprising: A bioreactor (1), - an inlet (4) for a flow comprising a fluid phase enriched with biomass; - an outlet (5) for the treated liquid, which is arranged at the top of the bioreactor; A bioreactor (1), A biomass separator (2) separated from the bioreactor, - an inlet (6) for a stream comprising treated liquid, located at the top of the biomass separator, the inlet (6) being fluidly connected to the outlet (5) of the bioreactor; - one or more inclined plate settlers (7) arranged below the inlet (6), each inclined plate settler having an outlet (8) for a liquid phase having a reduced biomass content; A biomass separator (2), an outlet (9) for the biomass-enriched fluid, which is arranged in the lower part of the biomass separator below the one or more inclined plate settlers, the outlet (9) being fluidly connected to the inlet (4) of the bioreactor or to the inlet (20) of a mixing unit (19), the mixing unit including an outlet (21) being fluidly connected to the inlet (4) of the bioreactor; Including, The bioreactor, the lower part of the biomass separator or the mixing unit comprises an inlet (3) for an aqueous liquid containing a biodegradable substrate, Biomass separators are available in sizes from 0.5 to 30 m. 2 a footprint area A of the device or unit, the footprint area being equal to the horizontal surface area covered by a vertical projection onto the horizontal surface area of ​​the device or unit; The one or more tilted plate settlers include:

number

[0015] Thus, a first aspect of the present invention provides a process for the microbiological treatment of an aqueous liquid comprising a biodegradable substrate in an installation comprising: (i) a bioreactor comprising a biomass sludge; and (ii) a biomass separator separated from the bioreactor and comprising one or more inclined plate settlers, the process comprising: Introducing an aqueous liquid containing a biodegradable substrate into a bioreactor; - transferring the treated fluid containing biomass from an upper portion of the bioreactor to an upper portion of a biomass separator; Separating the treated fluid in one or more inclined plate settlers into a liquid phase having a reduced biomass content and a biomass-enriched fluid phase; Removing a liquid phase having a reduced biomass content from one or more inclined plate settlers; transferring at least a portion of the biomass-enriched fluid phase from a lower portion of the biomass separator to a bioreactor; Contains or introducing into the bioreactor a mixture of an aqueous liquid comprising the biodegradable substrate and at least a portion of a biomass-enriched fluid phase produced by one or more inclined plate settlers, the mixture being produced by (i) introducing the aqueous liquid comprising the biodegradable substrate into a lower portion of a biomass separator and mixing said aqueous liquid with at least a portion of the biomass-enriched fluid phase, or (ii) introducing both the aqueous liquid comprising the biodegradable substrate and at least a portion of the biomass-enriched fluid phase into a mixing unit and mixing said aqueous liquid with at least a portion of the biomass-enriched fluid phase; transferring the mixture of the aqueous liquid and at least a portion of the fluid phase to a bioreactor; - transferring the treated fluid comprising biomass from an upper portion of the bioreactor to an upper portion of the biomass separator; Separating the treated fluid into a liquid phase having a reduced biomass content and a biomass-enriched fluid phase in one or more inclined plate settlers; Removing a liquid phase having a reduced biomass content from one or more inclined plate settlers. Including, Biomass separators are available in sizes from 0.5 to 30 m. 2 a footprint area A of the device or unit, the footprint area being equal to the horizontal surface area covered by a vertical projection onto the horizontal surface area of ​​the device or unit; The one or more tilted plate settlers include:

number

[0016] The term "or," as used herein, is defined as "and / or" unless otherwise stated.

[0017] The terms "a" or "an," as used herein, unless otherwise stated, are defined as "at least one."

[0018] As used herein, the term "biodegradable substrate" refers to any organic matter that can be chemically oxidized, as can be determined by the Chemical Oxygen Demand (COD) test, as described in ISO 6060: 1989. The organic matter content is generally expressed in g COD, i.e., grams of oxygen consumed for the oxidation of the organic matter.

[0019] As used herein, the term "biomass" refers to non-dissolved organic matter containing active microorganisms.

[0020] As used herein, the term "biomass sludge" refers to a semi-solid slurry with a high biomass content.

[0021] The term "biogas" as used herein refers to gas (e.g., methane, carbon dioxide and mixtures of such gases) produced in the present process by anaerobic digestion of biodegradable substrates, for example, by biomass.

[0022] The term "inclined plate settler" as used herein refers to an apparatus that includes one or more inclined plate elements. An inclined plate settler can include, for example, two or more inclined plate elements in the form of rectangular plates or (circular, triangular, rectangular or hexagonal) open-topped cones. An inclined plate settler can be used for solid-liquid separation as well as gas-liquid separation. To achieve solid-liquid separation, the raw feed liquid flows upward between the inclined plate elements. During this, the solids settle on the plate elements and slide downward. Above the inclined plate elements, a clarified liquid is produced, which is withdrawn. Below the inclined plate elements, the separated particles can be collected as sludge, which can also be withdrawn. To achieve gas-liquid separation, the raw feed liquid flows downward between the inclined plate elements. During this, air bubbles collect below the plate elements and rise upward. Below the inclined plate elements, a degassed liquid is produced, which is withdrawn. Above the inclined plate elements, the separated air bubbles can form a gas phase, which can also be withdrawn. The tilted plate settler may also include one or more tilted plate elements that form a spiral-shaped channel, as described in WO 2020 / 260354.

[0023] The term "total projected surface area" as used herein refers to the horizontal component of the surface area of ​​an inclined plate element. If the inclined plate element is a rectangular plate or an open-topped cone, the total projected surface area is equal to the surface area covered by the vertical projection of the inclined plate element onto a horizontal flat surface. If the inclined plate element forms a helical shaped channel, the collective surface area may exceed the surface area covered by its vertical projection if the helix rotates more than 360°.

[0024] The term "footprint area" as used herein with respect to a device or unit refers to the horizontal surface area covered by the vertical projection of the device or unit onto that horizontal surface area. Thus, the footprint area of ​​an upright cylinder is equal to the surface area of ​​the circular cross section of the cylinder.

[0025] In this specification, whenever terms such as "upper", "lower", "top", "middle", "bottom" and the like are used, unless otherwise specified, these terms refer to the location of the equipment when it is operational.

[0026] As used herein, the term "upper" refers to the upper half, particularly the upper third, and more particularly the upper quarter, of the unit. The term "lower" refers to the lower half, particularly the lower third, and more particularly the lower quarter, of the unit.

[0027] The term "near" as used herein means, unless otherwise specified, a relative height of no more than + / - 15% from the reference point, especially no more than + / - 10% from the reference point. The relative height is the distance from the base divided by the total height of the unit (the difference in height between the base and the top).

[0028] The requirement of PSAR ≥ 2.8 + 0.17A means that the minimum PSAR of the inclined plate settler or settlers depends on the footprint area of ​​the biomass separator. This dependency is shown in the table below for cylindrical biomass separators of different diameters. These separators are fitted with inclined plate settlers that include several rectangular plates (plate spacing: 8 cm, plate thickness 8 mm). The plate angle (30-80°), width (0.3-4.0 m) and length (0.4-3.0 m) of the rectangular plates are selected to maximize the total projected surface area realized by a single settler inside the footprint area of ​​the cylindrical biomass separator. In practice, such maximum utilization is not achieved, since some extra space is needed to close the open side of the inclined plate settler and to allow the installation of the device inside the cylinder. The rectangular configuration of the inclined plate settler leaves open space between the inside of the cylinder and the four sides of the settler, allowing the fluid to pass through the settler and subsequently enter the lower end of the settler. The following table shows the number of these settlers required to meet the aforementioned PSAR requirements.

[0029] [Table 1]

[0030] From this table it is clear that a stack of at least two tilted plate settlers is required to achieve the minimum PSAR.

[0031] According to a particularly preferred embodiment, the bioreactor used in accordance with the present invention is a granular sludge bed (GSB) reactor. In a typical GSB reactor, wastewater is introduced into the lower part of the bioreactor and flows upwards through a granular sludge bed containing microorganisms that decompose the organic substrates present in the wastewater, thereby forming biogas.

[0032] The process can be suitably used to microbiologically treat various types of aqueous liquids containing biodegradable substrates. Preferably, the aqueous liquid containing biodegradable substrates is wastewater. Examples of wastewaters that can be suitably treated are wastewaters from the production of dairy products or dairy ingredients (e.g. cheese), pulp and paper, agricultural products (e.g. sugar, starch, vegetable oils), fermented beverages (e.g. wine, beer), biofuels, petrochemicals or chemicals.

[0033] In the present process, the aqueous liquid containing the biodegradable substrate is preferably at least 10 ml 3 Flow speed is preferably 20 to 1000 m / hr. 3 / hr flow rate.

[0034] The aqueous liquid comprising the biodegradable substrate preferably contains at least 90% by weight water, more preferably at least 95% by weight, and most preferably at least 98% by weight water.

[0035] The total organic matter content of the aqueous liquid containing the biodegradable substrate is preferably greater than 0.1 g COD / L, more preferably it is in the range of 0.5 to 100 g COD / L, most preferably in the range of 1.5 to 25 g COD / L.

[0036] The biomass present in the bioreactor comprises active microorganisms capable of converting at least a portion of the biodegradable substrate into biogas. Examples of microorganisms that can be used include bacteria and archaea. Preferably, the microorganisms used are anaerobic microorganisms. According to a particularly preferred embodiment, the biomass comprises one or more species of methanogenic bacteria or methanogenic archaea.

[0037] According to a further preferred embodiment, the active microorganisms used in the present process grow in aggregates, often referred to as "granular biomass".

[0038] The bioreactor used in the process is preferably operated under anaerobic conditions. Preferably, the average redox potential of the fluid contained in the bioreactor is not below -200 mV, more preferably not below -300 mV. The "redox potential" can be suitably measured by a redox electrode, as described in 2580 Oxidation-Reduction Potential (ORP), Standard Methods For the Examination of Water and Waste water (published online: August 27, 2018, revised: July 19, 2021).

[0039] The bioreactor fluid is preferably maintained at a temperature in the range of 10-40°C, more preferably 20-39°C.

[0040] The pH of the bioreactor fluid is preferably maintained within the range of 6 to 8, more preferably 6.8 to 7.5.

[0041] In a preferred embodiment, the biogas is mixed with 1 m of fluid contained in the bioreactor. 3 More preferably, the biogas is produced in the bioreactor at a rate of at least 80 L / h per m 3 of fluid contained in the bioreactor. 3 It is produced in a bioreactor at a rate of at least 80 to 1250 L / hr per

[0042] The biogas produced by the present process preferably contains at least 50% by weight methane, more preferably at least 65% by weight.

[0043] According to a particularly preferred embodiment, the bioreactor does not include a solid-liquid separator. The absence of any solid-liquid separator in the bioreactor gives the advantage that these separators can be cleaned without the need to remove the biomass from the bioreactor.

[0044] The biomass separator used in the present process can be placed outside the bioreactor or can be placed inside the bioreactor as a separate unit. Preferably, the biomass separator is placed outside the bioreactor.

[0045] In the present process, the biomass separator is preferably operated under anaerobic conditions. Preferably, the average redox potential of the fluid contained in the biomass separator is less than -200mV, more preferably less than -300mV.

[0046] According to a particularly preferred embodiment, the volume of the biomass separator is substantially smaller than the volume of the bioreactor. Preferably, the volume of the biomass separator is at most one third, more preferably one fourth to one twenty-fifth, and most preferably one fifth to one fifteenth of the volume of the bioreactor.

[0047] According to another preferred embodiment, the footprint area of ​​the biomass separator is substantially smaller than the footprint area of ​​the bioreactor. Preferably, the footprint area of ​​the biomass separator is at most one third, more preferably one fourth to one twenty-fifth, and most preferably one fifth to one fifteenth of the footprint area of ​​the bioreactor.

[0048] The biomass separator of the present invention is a vertical device. Typically, the biomass separator is 1 m -1, more preferably 2 to 30 m -1 , most preferably 2 to 12 m -1 has a height:footprint area ratio of greater than

[0049] Preferably, at least a portion of the depleted liquid phase is not recycled to either the bioreactor or the biomass separator, more preferably, none of the depleted liquid phase is recycled to either the bioreactor or the biomass separator.

[0050] In one embodiment of the present invention, the tilted plate elements of one or more tilted plate settlers consist of rectangular plates. The projected surface area (psa i ) can be calculated as follows: psa i =l i ×w i ×cos(Θ i ) During the ceremony, l i denotes the length of the inclined plate I in m, w i denotes the width of the inclined plate I in m, Θi is the tilt plate i Represents the pitch of.

[0051] The separation efficiency of inclined plate settlers, including rectangular plates, increases with plate length, although no substantial increase in efficiency is realized when the plate length exceeds 3 m. Thus, the length of the inclined plate (l i ) is preferably in the range of 0.4 to 3 m, more preferably 0.6 to 2.5 m, and most preferably 0.8 to 2 m.

[0052] Width of the inclined plate (w i ) is preferably in the range of 0.3 to 7 m, more preferably 0.6 to 6 m, and most preferably 1 to 5 m.

[0053] The pitch of the inclined plate (Θ i) is preferably in the range of 30 to 80°, more preferably in the range of 40 to 70°, and most preferably in the range of 45 to 65°.

[0054] In another embodiment of the invention, the inclined plate elements of the one or more inclined plate settlers consist of open-top conical tapered tubes stacked on top of each other. The distance between the outer and inner edges of the cones is preferably in the range of 0.3-7 m, more preferably in the range of 0.6-6 m, and most preferably in the range of 1-5 m.

[0055] The half angle of the cone (the angle between the cone surface and the cone axis) is preferably in the range of 30 to 80°, more preferably in the range of 40 to 70°, and most preferably 45 to 65°.

[0056] In yet another embodiment of the invention, the inclined plate elements of the one or more inclined plate settlers form a helical shaped channel. According to a preferred embodiment, this type of inclined plate settler comprises: at least two concentric enclosures, including an outermost enclosure and an innermost enclosure, and defining at least one concentric cavity; one or more helical shaped channels formed within at least one concentric cavity; a fluid inlet for receiving a fluid, the fluid inlet being disposed at a lower portion of the one or more spiral-shaped channels; a solids outlet arranged at the bottom of the separation device for discharging solids contained in the fluid; and A liquid outlet for discharging liquid contained in the fluid, located at the top of the one or more spiral-shaped channels.

[0057] The total projected surface area of ​​the inclined plate settler including the helical channels is calculated as follows:

number

[0058] The average spacing between the tilted plate elements of the tilted plate settler is preferably in the range of 2 to 18 cm, more preferably 4 to 14 cm, and most preferably 8 to 12 cm.

[0059] The footprint area of ​​a biomass separator is typically between 1 and 22 m 2 , more preferably 1.5 to 15 m 2 The range is.

[0060] To achieve effective separation in a biomass separator, space must be made available around the inclined plate settler or settlers to allow sufficient, preferably non-turbulent, downward flow. Preferably, in the portion of the biomass separator in which the inclined plate settler or settlers are located, 20-60% of the cross-sectional area is available for downward flow.

[0061] The total projected surface area ratio (PSAR) provided by the one or more tilted plate settlers preferably satisfies the following condition: PSAR≧3.2+0.17A.

[0062] More preferably, the PSAR satisfies the following condition: PSAR≧3.5+0.17A.

[0063] Most preferably, the PSAR satisfies the following condition: 4+0.17A≦PSAR≦25+0.17A.

[0064] The tilted plate settler or settlers used in accordance with the present invention preferably each comprise at least 4, more preferably at least 5, and most preferably between 6 and 30 tilted plate elements.

[0065] The biomass separator used in the present process preferably comprises two or more inclined plate settlers stacked on top of each other. The use of stacked settlers has the advantage that the volume of the biomass separator can be efficiently utilized and the separator has a high footprint of less than 1 m 2This provides the advantage of being able to accommodate a greater projected inclined plate surface area per well. Thus, in a preferred embodiment, the biomass separator comprises at least 2, more preferably 2 to 15, and most preferably 3 to 5 stacked inclined plate settlers.

[0066] If the biomass separator includes two or more inclined plate settlers, the biomass-depleted liquid phases removed from each of the settlers may suitably be combined into a single stream, which may occur inside or outside the biomass separator.

[0067] The biomass-enriched fluid phase is preferably collected near the bottom of the biomass separator.

[0068] In an advantageous embodiment of the invention, the aqueous liquid containing the biodegradable substrate is introduced directly into the bioreactor. Preferably, said aqueous liquid is introduced into the lower part of the bioreactor. By introducing the aqueous liquid containing the biodegradable substrate into the lower part of the bioreactor, an upward flow is created through the biomass sludge of the bioreactor, thereby maximizing biomass / substrate contact. The performance of the bioreactor strongly depends on an efficient distribution of the incoming flow of the aqueous liquid containing the biodegradable substrate. As a result, in a preferred embodiment, upon introduction of the aqueous liquid containing the biodegradable substrate, said aqueous liquid is distributed evenly underneath the biomass sludge.

[0069] In another advantageous embodiment, the process comprises introducing into the bioreactor a mixture of an aqueous liquid comprising a biodegradable substrate and at least a portion of a biomass-enriched fluid phase produced by one or more inclined plate settlers, the mixture being produced by introducing the aqueous liquid comprising a biodegradable substrate into the lower part of the biomass separator and mixing said aqueous liquid with at least a portion of the biomass-enriched fluid phase. As explained below, introducing the aqueous liquid into the lower part of the biomass separator provides the advantage that the biomass separator can further function as an equalization tank.

[0070] According to a particularly preferred embodiment, the biomass separator used in this embodiment of the invention comprises a conditioning chamber arranged below the one or more inclined plate biomass separators. The aqueous liquid containing the biodegradable substrate is introduced into said conditioning chamber, where it is mixed with the biomass-enriched fluid phase, after which the mixture of the aqueous liquid and the fluid phase is transferred to the bioreactor. Fluctuations in the inflow of the aqueous liquid containing the biodegradable substrate into the bioreactor and undesirable fluctuations in the quality of the fluid stream being treated in the bioreactor can be minimized by using such a conditioning chamber. Furthermore, the risk of clogging of the conduit connecting the lower end of the biomass separator with the bioreactor is also substantially reduced by the presence of a conditioning chamber below the one or more inclined plate settlers at the lower end of the biomass separator.

[0071] The mixture of aqueous liquid and fluid phases is preferably transferred from the conditioning chamber to the lower part of the bioreactor. By introducing the mixture to the lower part of the bioreactor, an upward flow is generated through the biomass sludge of the bioreactor. As already mentioned above, the performance of the bioreactor strongly depends on the efficient distribution of the incoming flow containing the biodegradable substrate. As a result, in a preferred embodiment, upon introduction of the mixture of aqueous liquid and fluid phases, said mixture is distributed evenly below the biomass sludge.

[0072] Preferably, the volume of the conditioning chamber represents 5-25%, more preferably 10-15% of the total volume of the biomass separator.

[0073] In another advantageous embodiment, the process comprises introducing into the bioreactor a mixture of an aqueous liquid containing a biodegradable substrate and at least a portion of a biomass-enriched fluid phase produced by one or more inclined plate settlers, the mixture being produced by introducing both the aqueous liquid containing a biodegradable substrate and at least a portion of the fluid phase into a mixing unit and mixing said aqueous liquid with at least a portion of the biomass-enriched fluid phase, after which the mixture of the aqueous liquid and the fluid phase is transferred to the bioreactor, preferably to the lower part of the bioreactor. By introducing the mixture into the lower part of the bioreactor, an upward flow through the biomass sludge of the bioreactor is generated. In a preferred embodiment, upon introduction of the mixture of the aqueous liquid and the fluid phase, said mixture is distributed evenly under the biomass sludge.

[0074] The mixing unit used in accordance with this embodiment can take the form of a simple tube, a static mixer, a mixing chamber or a mixing vessel.

[0075] According to a particularly preferred embodiment of the present process, the highest outlet of the one or more inclined plate settlers is positioned at 20-90% of the height of the fluid column within the biomass separator, more preferably 40-85%, and most preferably 60-80%.

[0076] In a further preferred embodiment of the process, the lowest inlet of the one or more inclined plate settlers is positioned between 1 and 67%, more preferably between 2 and 25%, and most preferably between 2.5 and 20% of the height of the fluid column within the biomass separator.

[0077] The distance between the highest outlet of the one or more inclined plate settlers and the lowest inlet of the one or more inclined plate settlers is preferably in the range of 10-85% of the height of the fluid column in the biomass separator, more preferably in the range of 15-70%, and most preferably in the range of 25-55%.

[0078] According to a preferred embodiment, the biomass separator has a length of at least 22 m 3 / hour / m 2 , preferably at least 33 m 3 / hour / m 2 Flow rate of 44 to 440 m 3 / hour / m 2 where the flow rate is calculated by dividing the flow rate of the treated fluid through the biomass separator by the footprint area of ​​the biomass separator.

[0079] According to a particularly preferred embodiment, the biomass separator has a length of at least 20 m 3 / hour / m 2 , preferably at least 30 m 3 / hour / m 2 Flow rate of 40 to 200 m 3 / hour / m 2 wherein the flow rate is calculated by dividing the flow rate of the biomass-reduced liquid through the biomass separator by the footprint area of ​​the biomass separator.

[0080] It is preferred that the bioreactor and biomass separator operate at very similar fluid levels. Preferably, the fluid levels of the bioreactor and biomass separator differ by no more than 5%, more preferably no more than 1%, where "fluid level" refers to the absolute height of the fluid column.

[0081] The bioreactor and biomass separator are preferably located on the same horizontal plane, and therefore the height of the fluid column in the bioreactor and the height of the fluid column in the biomass separator preferably differ by no more than 5%, more preferably no more than 1%.

[0082] Typically, the height of the fluid column within the bioreactor ranges from 5 to 28 m, more preferably from 10 to 24 m.

[0083] In this process, the microbial conversion of the biodegradable substrate is typically accompanied by the growth of microorganisms and an increase in biomass. In order to maintain constant conditions in the bioreactor, it is preferable to remove the biomass at a rate comparable to the rate at which excess biomass is produced inside the bioreactor. Thus, in a preferred embodiment, a portion of the biomass-enriched fluid phase obtained from the separation unit is returned to the bioreactor and another portion is discarded.

[0084] In this process, the biogas produced rises to the top of the bioreactor and is discharged from the fluid into the headspace of the reactor.

[0085] The treated fluid transferred to the biomass separator typically also contains some biogas. In a preferred embodiment, the downward flow velocity in the biomass separator is low enough to allow the biogas to rise to the top of the biomass separator. By using the top of the biomass separator as a gas / liquid separator, the loss of biogas via the exiting flow of the liquid phase with reduced biomass content is effectively minimized. In this way, it is also avoided that the biogas interferes with the separation of the biomass in the inclined plate settler or settlers.

[0086] Biogas separation at the top of the bioreactor and / or at the top of the biomass separator may be assisted by a gas-liquid separator located below the fluid surface (above the inclined plate settler or settlers) at the top of the bioreactor and / or at the top of the biomass separator. Preferably, gas-liquid separation is achieved without the use of a gas-liquid separator.

[0087] If one or more gas-liquid separators are used to separate the biogas, these separators or separators are preferably installed in the biomass separator and not in the bioreactor. Thus, these separators can be cleaned without the need to remove the biomass from the bioreactor. Examples of gas-liquid separators that can be used include inclined plate settlers and cyclones.

[0088] In another advantageous embodiment of the invention, both the bioreactor and the biomass separator include a headspace that is filled with biogas, the bioreactor headspace and the biomass separator headspace are connected by a gas conduit, and the process includes removing the biogas from the bioreactor headspace or the biomass separator headspace.

[0089] As explained above, to achieve maximum separation efficiency in a biomass separator, it is advantageous to create a tangential downward flow at the top of the biomass separator. This can be achieved, for example, by using a biomass separator in the form of an upright cylinder and introducing the treated fluid horizontally into the top of the biomass separator at an angle of less than 20°, more preferably less than 10°, to the inner wall of the separator.

[0090] The equipment used in the process may include two or more bioreactors and / or two or more biomass separators.

[0091] In an embodiment of the invention, the facility includes one bioreactor connected to two or more biomass separators. In this configuration, the treated fluid is transferred from the top of the bioreactor to the top of the two or more biomass separators, and a stream containing a biomass-enriched fluid phase is transferred from the one or more biomass separators to the bioreactor. The PSAR of this configuration is calculated by first calculating the total projected surface area of ​​the combination of separators and dividing it by the total footprint area of ​​the two or more biomass separators. The flow rate at which the combination of two or more biomass separators operates is calculated by dividing the combined flow rate through the two or more biomass separators by the total footprint area of ​​the two or more biomass separators.

[0092] In another embodiment, the facility includes two or more bioreactors connected to a single biomass separator. In this configuration, the treated fluid is transferred from the top of the two or more bioreactors to the top of the single biomass separator, and a stream containing a biomass-enriched fluid phase is transferred from the biomass separator to the two or more bioreactors.

[0093] Preferably, the process is operated in equipment as described below.

[0094] Another aspect of the invention is an installation for the microbiological treatment of an aqueous liquid containing a biodegradable substrate, comprising: A bioreactor (1), - an inlet (4) for a flow comprising a fluid phase enriched with biomass; - an outlet (5) for the treated liquid, which is arranged at the top of the bioreactor; A bioreactor (1), A biomass separator (2) separated from the bioreactor, - an inlet (6) for a stream comprising treated liquid, said inlet (6) being arranged at the top of the biomass separator, said inlet for treated liquid being fluidly connected to the outlet (5) of the bioreactor; - one or more inclined plate settlers (7) arranged below the inlet (6), each inclined plate settler having an outlet (8) for a liquid phase having a reduced biomass content; (2) a biomass separator comprising: an outlet (9) for the biomass-enriched fluid, which is arranged in the lower part of the biomass separator below the one or more inclined plate settlers, the outlet (9) being fluidly connected to the inlet (4) of the bioreactor or to the inlet (20) of a mixing unit (19), the mixing unit including an outlet (21) being fluidly connected to the inlet (4) of the bioreactor; Including, The bioreactor, the lower part of the biomass separator or the mixing unit comprises an inlet (3) for an aqueous liquid containing a biodegradable substrate, Biomass separators are available in sizes from 0.5 to 30 m. 2 a footprint area A of the device or unit, the footprint area being equal to the horizontal surface area covered by a vertical projection onto the horizontal surface area of ​​the device or unit; The one or more tilted plate settlers include:

number

[0095] A preferred embodiment of the installation according to the invention has already been described above.

[0096] According to a particularly preferred embodiment, the bioreactor of the facility is a granular sludge bed (GSB) reactor.

[0097] The biomass separator is preferably positioned adjacent to the bioreactor.

[0098] Preferably, the bioreactor and the biomass separator are mounted on the same horizontal surface.

[0099] Preferably, the heights of the bioreactor and the biomass separator differ by no more than 20%, more preferably no more than 10%.

[0100] According to a preferred embodiment, the bioreactor includes an influent distribution system (22) near the bottom of the bioreactor that is fluidly connected to the inlet (3) or the inlet (4), which distributes the flow containing the biodegradable substrate evenly across the bottom end of the bioreactor.

[0101] The bioreactor and / or biomass separator may include one or more gas-liquid separators disposed at the top of the bioreactor or separator. The one or more gas-liquid separators are preferably disposed at the top of the separator. Preferably, no gas-liquid separator is provided in the bioreactor.

[0102] Most preferably, neither the bioreactor nor the biomass separator uses a gas-liquid separator to achieve gas-liquid separation, i.e., the biogas is separated by allowing it to escape to the top of the bioreactor and the top of the biomass separator.

[0103] The gas-liquid separator is preferably selected from an inclined plate settler, a cyclone, and combinations thereof.

[0104] Preferably, the top of the bioreactor and the top of the biomass separator are connected by a conduit fluidly connecting a gas connection (15) arranged at the top of the bioreactor with a gas connection (16) arranged at the top of the biomass separator. The gas connection (15) is arranged above the outlet (5) for the treated fluid, and the gas connection (16) is arranged above the inlet for the treated fluid (6). This configuration gives the advantage that both the bioreactor and the biomass separator operate at the same headspace pressure and a single outlet for further processing of the biogas is sufficient.

[0105] In a further preferred embodiment, the biomass separator comprises a conditioning chamber (18) located below the one or more inclined plate biomass separators, the conditioning chamber comprising an inlet (3) for an aqueous liquid comprising a biodegradable substrate and an outlet (4) for a stream comprising a biomass-enriched fluid phase, the stream comprising a biomass-enriched fluid phase being generated in the conditioning chamber by mixing the aqueous liquid with the biomass-enriched fluid phase.

[0106] In an alternative embodiment, the installation comprises a mixing unit (19) comprising an inlet (3) for an aqueous liquid comprising a biodegradable substrate, an inlet (20) for a biomass-enriched fluid phase that is fluidly connected to the outlet (9) of the biomass separator, and an outlet (21) fluidly connected to the inlet (4) of the bioreactor. [Brief description of the drawings]

[0107] [Figure 1] 1 shows diagrammatically an installation for microbiological treatment which can be used to operate the process according to the invention; [Diagram 2] 1 shows diagrammatically an alternative installation for microbiological treatment which can be used to operate the process according to the invention; [Diagram 3] 1 shows diagrammatically yet another alternative installation for microbiological treatment which can be used to operate the process according to the invention; [Figure 4]1 shows a schematic horizontal cross section of the top of a biomass separator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0108] Figure 1 shows diagrammatically an installation for use in the process according to the invention. The installation comprises a bioreactor (1) and a biomass separator (2).

[0109] An aqueous liquid containing biodegradable substrates is introduced into the bottom of the bioreactor (3) via an influent distribution system (22). The influent fluid stream flows upwards through the bioreactor and through a granular biomass bed (23) where at least a portion of the biodegradable substrates are converted to biogas by the anaerobic microorganisms ("biomass"). The biogas naturally rises to the top of the bioreactor. Most of the biogas is separated from the fluid at the bioreactor liquid level (10) and collected in the reactor headspace (12). From the headspace it is led out of the bioreactor via biogas collection piping (13), which may alternatively also be connected to the biomass separator headspace. The treated liquid (low in biodegradable substrate concentration) flows from the top of the bioreactor through one or more outlets (5) to one or more inlets (6) at the top of the biomass separator.

[0110] At the top of the biomass separator, further / final degassing takes place at the liquid surface (11). Biogas in the headspace of the biomass separator flows to the headspace of the bioreactor via the biogas outlet (16) and the biogas inlet (15) and can exit the bioreactor via the biogas collection piping. The degassed fluid then flows downwards through the biomass separator. At least in the lower part of the biomass separator, one or more inclined plate settlers (7) are arranged. The inlets of the inclined plate settlers are fed from the downward fluid flow. In case of multiple inclined plate settlers, these biomass separators are stacked vertically and fed with fluid flows at different heights. To ensure efficient separation in the inclined plate settlers, a uniform fluid flow distribution over the multiple inclined plate settlers is necessary and the flow through the inclined plate settlers should not be too turbulent. The first one can be achieved by designing the piping (8) collecting the biomass-poor fluid such that the total flow rate is evenly distributed over the multiple inclined plate settlers. The second can be achieved by allowing for a minimal space between the outer casing of the biomass separator and the inclined plate settler, allowing high flow rates to be achieved without causing significant turbulence near the inlet to the separation device. The combined flow of biomass-lean fluids exiting the biomass separator is controlled by a valve (17) to maintain a stable water level in the biomass separator and bioreactor. The biomass-rich fluid stream flows further downwards towards the bottom of the biomass separator, as does the recirculation flow that did not pass through the inclined plate settler.

[0111] At the bottom of the biomass separator, the combined recycle stream and biomass-rich fluid stream are extracted as a biomass-enriched fluid phase through the biomass separator outlet (9) and introduced into the bioreactor through inlet (4). This can be done using a mechanical pump or by creating a gas lift that drives the flow from the biomass separator to the bioreactor. The combined biomass-rich recycle stream and fluid stream can also be introduced into the bioreactor along with an aqueous liquid containing the biodegradable substrate through inlet (3).

[0112] The fluid level in the biomass separator is similar to that of the bioreactor, and the fluid level in the bioreactor is higher during normal operation to allow gravity flow from the bioreactor to the biomass separator. The volume of the biomass separator is efficiently utilized by vertically expanding the inclined plate settler. This can be done, for example, by stacking multiple inclined plate settlers on top of each other, or by vertically expanding the capacity of a single settler, as described in China Utility Model No. 2880214. By vertically expanding the settling area, the fluid handling capacity per square meter of the biomass separator footprint area can be increased by up to 20 m2, depending on how much the settling area is expanded vertically. 3 / m 2 / h or more. The footprint area of ​​the biomass separator is larger than the footprint area of ​​the inclined plate settler, considering that the inclined plate separator or separators are located inside the biomass separator casing and free space is required around the inclined plate settler to allow fluid to flow through.

[0113] In an embodiment of the present invention, the top of the biomass separator is utilized as an efficient degasser. The top of the biomass separator can also provide additional volume that allows for high recirculation flow rates to be achieved without excessive turbulence near the inlet of the inclined plate settler or settlers, which are located at the bottom of the biomass separator. Both of the above-mentioned objectives of the top of the biomass separator can be further optimized by introducing the fluid flow eccentrically to the top of the biomass separator, thus creating a tangential flow pattern.

[0114] A high water level in the biomass separator is beneficial for the separation efficiency of the inclined plate settler(s). To ensure that the inclined plate settler(s) benefit from separation under high hydrostatic pressure, ideally the top end of the inclined plate settler(s) is located at least 5 meters below the water level of the biomass separator.

[0115] Maintenance of the biomass separator can be easily performed, for example, by closing the inlet for the aqueous liquid containing the biodegradable substrate (3), returning the tail of the biomass to the bioreactor, and then stopping the recirculation flow. The biomass separator is then isolated from the bioreactor by closing the interconnecting fluid connections (4 and 9, 5 and 6) and the gas connections (15 and 16). There is no need to wait until the production of residual biogas stops in the bioreactor, since this biogas can continue to be collected (13) from the headspace of the bioreactor (12). Maintenance / inspection / cleaning of the biomass separator can then be performed while the anaerobic biomass remains inside the bioreactor.

[0116] FIG. 2 shows diagrammatically an alternative installation for use in the process according to the invention.

[0117] In this embodiment of the invention, the lower end of the biomass separator serves as a so-called equalization tank. The aqueous liquid containing the biodegradable substrate is introduced into a conditioning chamber (18) located at the lower end of the biomass separator (2). The aqueous liquid containing the biodegradable substrate, the biomass-rich fluid stream and the recycle stream are mixed in the conditioning chamber and the mixed stream leaves the biomass separator via the outlet (9) and enters the inlet (4) of the bioreactor. If necessary, further conditioning of the mixed stream can be performed, for example by adding chemicals to adjust the pH or to serve as a nutrient supply for the biomass of the bioreactor.

[0118] FIG. 3 shows diagrammatically yet another alternative installation for use in the process according to the invention.

[0119] In this embodiment, the biomass-enriched fluid phase and the aqueous liquid containing the biodegradable substrate are mixed together before being introduced into the bioreactor through the influent distribution system. The aqueous liquid containing the biodegradable substrate is introduced into the mixing unit (19) via the inlet (3). At the same time, the biomass-enriched fluid phase is transferred from the outlet (9) of the biomass separator to the inlet (20) of the mixing unit. If necessary, chemicals (e.g. to adjust the pH) or nutrients can also be introduced into the mixing unit. The mixed stream is then transferred from the outlet (21) of the mixing unit to the inlet (4) of the bioreactor.

[0120] Figure 4 shows a schematic horizontal cross section of the top of the biomass separator (2). Treated fluid enters the biomass separator via an inlet (6), which introduces the treated fluid at an angle α to the inner wall of the separator, thereby creating a downward spiral flow. [Explanation of symbols]

[0121] 1. Bioreactor 2. Biomass separator 3. Inlet for aqueous liquid containing biodegradable matrix 4. Inlet for the flow containing the biomass-enriched fluid phase 5 Outlet for treated fluid 6 Inlet for the stream containing the treated liquid 7. Tilt Plate Settler 8. Outlet for liquid phase with reduced biomass content 9. Outlet for the flow containing the biomass-enriched fluid phase 10 Bioreactor Fluid Levels 11 Biomass separator fluid level 12 Bioreactor Headspace 13 Headspace of Biomass Separator 15 Gas connection 16 Gas connection 17 Control valve 18 Adjustment chamber 19 Mixed Unit 20 Inlet for biomass-enriched fluid phase 21 Outlet for the flow containing the biomass-enriched fluid phase 22 Influent Distribution System 23 Granular biomass bed

Claims

1. 1. A process for the microbiological treatment of an aqueous liquid containing a biodegradable substrate in an installation comprising: (i) a bioreactor containing biomass sludge; and (ii) a biomass separator separated from said bioreactor and comprising one or more inclined plate settlers, comprising: - introducing the aqueous liquid containing a biodegradable substrate into the bioreactor; - transferring treated fluid containing biomass from an upper portion of the bioreactor to an upper portion of the biomass separator; - separating the treated fluid in the one or more inclined plate settlers into a liquid phase having a reduced biomass content and a biomass-enriched fluid phase; - removing a liquid phase having a reduced biomass content from said one or more inclined plate settlers; - transferring at least a portion of the biomass-enriched fluid phase from a lower portion of the biomass separator to the bioreactor; Contains or introducing into the bioreactor a mixture of the aqueous liquid comprising a biodegradable substrate and at least a portion of a biomass-enriched fluid phase produced by the one or more inclined plate settlers, the mixture being produced by (i) introducing the aqueous liquid comprising a biodegradable substrate into the lower portion of the biomass separator and mixing the aqueous liquid with at least a portion of the biomass-enriched fluid phase, or (ii) introducing both the aqueous liquid comprising a biodegradable substrate and at least a portion of the biomass-enriched fluid phase into a mixing unit and mixing the aqueous liquid with at least a portion of the biomass-enriched fluid phase; - transferring said mixture of said aqueous liquid and said at least a portion of a fluid phase to said bioreactor; - transferring treated fluid containing biomass from the upper portion of the bioreactor to the upper portion of the biomass separator; - separating the treated fluid in the one or more inclined plate settlers into a liquid phase having a reduced biomass content and a biomass-enriched fluid phase; Removing a liquid phase having a reduced biomass content from said one or more inclined plate settlers. Including, The biomass separator is 0.5 to 30 m ２ a footprint area A of said device or unit, said footprint area being equal to the horizontal surface area covered by a vertical projection onto said horizontal surface area of ​​said device or unit; The one or more tilted plate settlers include: [0010] - PSAR=PSA / A (In the formula, psa ｉ is the total projected surface area of ​​the inclined plate element i, m ２ where the total projected surface area is equal to the horizontal component of the surface area of ​​the inclined plate element; PSAR ≧ 2.8 + 0.17A) The process includes a total of n slanted plate elements, which together provide a total projected surface area (PSA) and a total projected surface area ratio (PSAR) calculated as:

2. The biomass separator has a length of at least 20 m. ３ / hour / m ２ 2. The process of claim 1, wherein the process is operated to produce the liquid phase having reduced biomass content at a flow rate of about 1000 nm to about 1000 nm, the flow rate being calculated by dividing the flow rate of the liquid phase having reduced biomass content by the footprint area of ​​the biomass separator.

3. 3. The process of claim 1 or 2, wherein the volume of the biomass separator is at most one-fifth the volume of the bioreactor.

4. 4. The process of claim 1, wherein the height of the fluid column in the bioreactor and the height of the fluid column in the biomass separator differ by no more than 5%.

5. The biomass separator is 1 m －１ The process of any one of claims 1 to 4, having a height:footprint area ratio of greater than

6. The tilted plate elements of the one or more tilted plate settlers are rectangular plates, ｉ teeth, PSA ｉ =l ｉ ×w ｉ ×cos(θ) ｉ ) It is calculated as follows: l ｉ represents the length of the inclined plate I in m, W ｉ denotes the width of the inclined plate I in m, Θ ｉ The process according to any one of claims 1 to 5, wherein denotes the pitch of the slanted plate i.

7. The process of any one of claims 1 to 5, wherein the tilted plate elements of the one or more tilted plate settlers consist of open-topped cones stacked on top of each other.

8. The tilted plate elements of the one or more tilted plate settlers include: at least two concentric enclosures, including an outermost enclosure and an innermost enclosure, and defining at least one concentric cavity; one or more spiral-shaped channels formed in the at least one concentric cavity; a fluid inlet for receiving a fluid, the fluid inlet being disposed at a lower portion of the one or more spiral-shaped channels; a solids outlet arranged at the bottom of the separation device for discharging solids contained in the fluid; a liquid outlet arranged at the top of the one or more spiral-shaped channels for discharging liquid contained in the fluid; The process according to any one of claims 1 to 5, comprising:

9. The process according to any one of claims 1 to 8, wherein the aqueous liquid containing the biodegradable substrate is introduced into the lower part of the bioreactor.

10. 9. The process of any one of claims 1 to 8, wherein the biomass separator comprises a conditioning chamber located below the one or more inclined plate settlers, the aqueous liquid comprising a biodegradable substrate is introduced into the conditioning chamber where it mixes with the biomass-enriched fluid phase, and then the mixture of aqueous liquid and fluid phase is transferred to a lower portion of the bioreactor.

11. The process according to any one of claims 1 to 10, wherein a part of the biomass-enriched fluid phase obtained from the separation unit is returned to the bioreactor and another part is discarded.

12. 12. The process of any one of claims 1 to 11, wherein both the bioreactor and the biomass separator include a headspace that is filled with biogas, the headspace of the bioreactor and the headspace of the biomass separator are connected by a gas conduit, and the process comprises removing biogas from the headspace of the bioreactor or the headspace of the biomass separator.

13. The process of any one of claims 1 to 12, wherein tangential downward flow is achieved at the upper portion of the biomass separator.

14. The process of any one of claims 1 to 13, wherein the bioreactor and the biomass separator are operated under anaerobic conditions.

15. 1. An installation for the microbiological treatment of an aqueous liquid containing a biodegradable substrate, comprising: A bioreactor (1), an inlet (4) for a flow comprising a fluid phase enriched with biomass; an outlet (5) for the treated liquid, located at the top of the bioreactor; A bioreactor (1), a biomass separator (2) separated from the bioreactor, an inlet (6) for a stream comprising treated liquid, located at the top of the biomass separator, said inlet (6) being fluidly connected to the outlet (5) of the bioreactor; - one or more inclined plate settlers (7) arranged below the inlet (6), each inclined plate settler having an outlet (8) for the liquid phase having a reduced biomass content; an outlet (9) for a biomass-enriched fluid, located at the bottom of the biomass separator below the one or more inclined plate settlers, said outlet (9) being fluidly connected to the inlet (4) of the bioreactor or to the inlet (20) of a mixing unit (19), said mixing unit comprising an outlet (21) fluidly connected to the inlet (4) of the bioreactor; A biomass separator (2) comprising Including, The bioreactor, the lower part of the biomass separator or the mixing unit comprises an inlet (3) for an aqueous liquid containing a biodegradable substrate, The biomass separator is 0.5 to 30 m ２ a footprint area A of said device or unit, said footprint area being equal to the horizontal surface area covered by a vertical projection onto said horizontal surface area; The one or more tilted plate settlers include: [0025] - PSAR=PSA / A (In the formula, psa ｉ is the total projected surface area of ​​the inclined plate element i, m ２ where the total projected surface area is equal to the horizontal component of the surface area of ​​the inclined plate element; PSAR ≧ 2.8 + 0.17A) The installation includes a total of n slanted plate elements providing both a total projected surface area (PSA) and a total projected surface area ratio (PSAR) calculated as:

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