Backwash orifice arrangement

Abstract

A solid-liquid separation system includes: a rotary filter configured to separate a solid-liquid containing stream into a filtrate component and a solid component, where the rotary filter has a point of rotation about which the rotary filter rotates; and a plurality of backwash orifices, including: a first backwash orifice arranged to discharge backwash water at a first region of the filter; and a second backwash orifice arranged to discharge the backwash water at a second region of the filter, different from the first region, where the first region is closer to the point of rotation than the second region, wherein the second backwash orifice discharges the backwash water at the second region and the first backwash orifice discharges the backwash water at the first region such that the second region experiences a higher flow rate than the first region.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 425,173, filed on November 14, 2022, the disclosure of which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present disclosure relates to solid-liquid separation, and in particular to systems and methods for cleaning filters in solid-liquid separation systems. Background Art

[0004] Solid-liquid separation, such as wastewater treatment, is considered an energy-intensive process. For example, during the wastewater treatment process, sludge typically forms a layer on the surface of the filter used to separate the sludge from the filtered water. Part of the energy required to achieve wastewater treatment is consumed to remove the sludge layer from the surface of the filter in order to allow the filter to continue to effectively separate the solid and liquid components. The sludge layer can be removed by using orifices that spray backwash water to contact the sludge layer, which removes the sludge layer from the surface of the filter. Discharging backwash water with insufficient backwash intensity (liters / min / m 2 ) results in inadequate filter cleaning. However, discharging backwash water at too high a backwash intensity and / or using too high a pumping pressure requires higher energy consumption. This problem is compounded for certain filter geometries and arrangements (e.g., rotating disc filters), where different areas of the filter create uneven coverage areas to be cleaned. Summary of the Invention

[0005] In view of the foregoing, there is a need for a system and method for cleaning a filter in a solid-liquid separation system that can reduce energy and cost consumption while adequately cleaning the filter.

[0006] In some non-limiting embodiments or aspects, a solid-liquid separation system includes: a rotary filter configured to separate a solid-liquid flow into a filtrate component and a solid component, wherein the rotary filter has a rotation point and a circumference, the rotary filter rotates around the rotation point, and the circumference defines the end of the filter; and a plurality of backwash orifices, comprising: a first backwash orifice, the first backwash orifice being arranged to discharge backwash water at a first region of the filter; and a second backwash orifice, the second backwash orifice being arranged to discharge backwash water at a second region of the filter that is different from the first region, wherein the first region is closer to the rotation point than the second region, wherein the second backwash orifice discharges the backwash water at the second region, and the first backwash orifice discharges the backwash water at the first region so that the second region experiences a higher flow rate than the first region.

[0007] The first and second regions may partially overlap, such that the first backwash orifice discharges the backwash water at the overlapping portion of the first and second regions and / or the second backwash orifice discharges the backwash water at the overlapping portion of the first and second regions. The rotary filter may include a first side through which the solid-containing liquid stream emerges and a second side through which the filtrate component emerges, wherein the plurality of backwash orifices discharge the backwash water at the second side. The second backwash orifices may discharge the backwash water at a higher flow rate than the first backwash orifices. The linear velocity of the rotary filter in the first region may be slower than the linear velocity of the rotary filter in the second region. The rotary filter may include a layer of the solid component formed on a surface, wherein the first and second backwash orifices are arranged to discharge the backwash water at the layer of the solid component to remove at least a portion of the layer of the solid component from the surface. The slope of a line representing backwash intensity as a function of distance from the rotation point of the rotary filter may be greater than or equal to -2 liters / min / m. 3 , such as greater than or equal to -1 liter / min / m 3 , greater than or equal to 0 liters / min / m 3 or greater than or equal to 1 liter / min / m 3 The slope of the line representing the backwash intensity as a function of the distance from the rotation point of the rotary filter may be greater than or equal to 2 liters / min / m 3 . The rotary filter may be a rotary disc. The rotary filter may be substantially vertical. The plurality of backwash orifices may be directly provided on the backwash pipe. Each of the plurality of backwash orifices may include a backwash nozzle, wherein each backwash nozzle may be configured to discharge the backwash water at a different flow rate. The solid-liquid separation system may be a wastewater treatment system, wherein the solid-liquid flow is a wastewater flow or a mixed liquor flow of a secondary biological treatment system, the solid component is a sludge component, and the filtrate component is filtered water.

[0008] In some non-limiting embodiments or aspects, a solid-liquid processing unit comprises: a plurality of solid-liquid separation systems as described herein; and a pump system fluidically connected to the plurality of solid-liquid separation systems, wherein the pump system is configured to pump backwash water to each of the plurality of solid-liquid separation systems.

[0009] A flow rate of the backwash water flowing to a first solid-liquid separation system among the plurality of solid-liquid separation systems may be within a deviation of 25% relative to a flow rate of the backwash water flowing to a second solid-liquid separation system among the plurality of solid-liquid separation systems. The solid-liquid separation system may be a wastewater treatment system, wherein the solid-liquid stream is a wastewater stream or a mixed liquor stream of a secondary biological treatment system, the solid component is a sludge component, and the filtrate component is filtered water.

[0010] In some non-limiting embodiments or aspects, a method for cleaning a solid-liquid separation system includes: arranging a plurality of backwash orifices for discharging backwash water at a rotary filter, the rotary filter being configured to separate a solid-liquid flow into a filtrate component and a solid component, wherein the rotary filter includes a layer of the solid component formed on a surface, wherein the rotary filter has a rotation point and a circumference, the rotary filter rotates around the rotation point, and the circumference defines an end of the filter; and discharging the backwash water from the plurality of backwash orifices at the filter to remove at least a portion of the layer of the solid component from the surface, wherein the plurality of backwash orifices include: a first backwash orifice, which is arranged to discharge backwash water at a first area of ​​the filter; and a second backwash orifice, which is arranged to discharge backwash water at a second area of ​​the filter that is different from the first area, wherein the first area is closer to the rotation point than the second area, wherein the second backwash orifice discharges the backwash water at the second area, and the first backwash orifice discharges the backwash water at the first area so that the second area experiences a higher flow rate than the first area.

[0011] The solid-liquid separation system can be a wastewater treatment system, wherein the solid-liquid stream is a wastewater stream or a mixed liquor stream of a secondary biological treatment system, the solid component is a sludge component, and the filtrate component is filtered water. The method can also include: collecting at least a portion of the sludge component layer removed from the surface; and removing at least a portion of the collected sludge component layer from a tank in which the wastewater treatment system is disposed. The method can also include: arranging the rotary filter in a tank; filling the tank with wastewater; rotating the filter to separate the filtrate component from the wastewater, wherein the filtrate component includes filtered water; and removing the filtered water from the tank.

[0012] The first area and the second area may partially overlap, so that the first backwashing orifice discharges the backwash water at the overlapping portion of the first area and the second area and / or the second backwashing orifice discharges the backwash water at the overlapping portion of the first area and the second area. The slope of the line representing the backwash intensity as a function of the distance from the rotation point of the rotary filter may be greater than or equal to -2 liters / min / m3 , such as greater than or equal to -1 liter / min / m 3 , greater than or equal to 0 liters / min / m 3 , greater than or equal to 1 liter / min / m 3 , or greater than or equal to 2 liters / min / m 3 .

[0013] Various non-limiting embodiments or aspects of the present disclosure will now be described and illustrated in the following numbered clauses:

[0014] Item 1: A solid-liquid separation system comprises: a rotary filter configured to separate a solid-liquid flow into a filtrate component and a solid component, wherein the rotary filter has a rotation point and a circumference, the rotary filter rotates around the rotation point, and the circumference defines the end of the filter; and a plurality of backwash orifices, comprising: a first backwash orifice, the first backwash orifice being arranged to discharge backwash water at a first region of the filter; and a second backwash orifice, the second backwash orifice being arranged to discharge backwash water at a second region of the filter that is different from the first region, wherein the first region is closer to the rotation point than the second region, wherein the second backwash orifice discharges the backwash water at the second region, and the first backwash orifice discharges the backwash water at the first region so that the second region experiences a higher flow rate than the first region.

[0015] Item 2: A solid-liquid separation system as described in Item 1, wherein the first region and the second region partially overlap, so that the first backwash orifice discharges the backwash water at the overlapping portion of the first region and the second region and / or the second backwash orifice discharges the backwash water at the overlapping portion of the first region and the second region.

[0016] Clause 3: The solid-liquid separation system of clause 1 or 2, wherein the rotary filter comprises a first side into which the solid-liquid stream is injected and a second side from which the filtrate component is emitted, wherein the plurality of backwash orifices discharge the backwash water at the second side.

[0017] Clause 4: The solid-liquid separation system according to any one of clauses 1 to 3, wherein the second backwash orifice discharges the backwash water at a higher flow rate than the first backwash orifice.

[0018] Clause 5: The solid-liquid separation system according to any one of Clauses 1 to 4, wherein the linear velocity of the rotary filter in the first zone is lower than the linear velocity of the rotary filter in the second zone.

[0019] Item 6: A solid-liquid separation system as described in any one of items 1 to 5, wherein the rotary filter includes a layer of the solid components formed on the surface, and wherein the first backwash orifice and the second backwash orifice are arranged to discharge the backwash water at the layer of the solid components so as to remove at least a portion of the layer of the solid components from the surface.

[0020] Clause 7: The solid-liquid separation system according to any one of clauses 1 to 6, wherein the slope of a line representing the backwash intensity as a function of the distance from the rotation point of the rotary filter is greater than or equal to -2 liters / min / m 3 , such as greater than or equal to -1 liter / min / m 3 , greater than or equal to -0.5 liters / min / m 3 , greater than or equal to 0 liters / min / m 3 , or greater than or equal to 1 liter / min / m 3 .

[0021] Clause 8: The solid-liquid separation system according to any one of clauses 1 to 7, wherein the slope of a line representing the backwash intensity as a function of the distance from the rotation point of the rotary filter is greater than or equal to 2 liters / min / m 3 .

[0022] Clause 9: The solid-liquid separation system of any one of Clauses 1 to 8, wherein the rotary filter is a rotating disc.

[0023] Clause 10: The solid-liquid separation system of any one of Clauses 1 to 9, wherein the rotary filter is substantially vertical.

[0024] Clause 11: The solid-liquid separation system according to any one of clauses 1 to 10, wherein the plurality of backwashing orifices are directly provided on the backwashing pipe.

[0025] Clause 12: The solid-liquid separation system of any one of clauses 1-11, wherein each of the plurality of backwash orifices comprises a backwash nozzle, wherein each backwash nozzle is configured to discharge the backwash water at a different flow rate.

[0026] Clause 13: The solid-liquid separation system of any one of clauses 1-12, wherein the solid-liquid separation system is a wastewater treatment system, wherein the solid-liquid stream is a wastewater stream or a mixed liquor stream of a secondary biological treatment system, the solid component is a sludge component, and the filtrate component is filtered water.

[0027] Item 14: A solid-liquid processing unit comprising: a plurality of solid-liquid separation systems as described in any one of Items 1 to 13; and a pump system in fluid communication with the plurality of solid-liquid separation systems, wherein the pump system is configured to pump backwash water to each of the plurality of solid-liquid separation systems.

[0028] Item 15: A solid-liquid processing unit as described in Item 14, wherein the flow rate of the backwash water flowing to the first solid-liquid separation system among the multiple solid-liquid separation systems is within a deviation of 25% relative to the flow rate of the backwash water flowing to the second solid-liquid separation system among the multiple solid-liquid separation systems.

[0029] Clause 16: The solid-liquid processing unit of clause 14 or 15, wherein the solid-liquid separation system is a wastewater treatment system, wherein the solid-liquid stream is a wastewater stream or a mixed liquor stream of a secondary biological treatment system, the solid component is a sludge component, and the filtrate component is filtered water.

[0030] Item 17: A method for cleaning a solid-liquid separation system, comprising: arranging a plurality of backwash orifices for discharging backwash water at a rotary filter, the rotary filter being configured to separate a solid-liquid flow into a filtrate component and a solid component, wherein the rotary filter includes a layer of the solid component formed on a surface, wherein the rotary filter has a rotation point and a circumference, the rotary filter rotates around the rotation point, and the circumference defines an end of the filter; and discharging the backwash water from the plurality of backwash orifices at the filter to remove at least a portion of the layer of the solid component from the surface, wherein the plurality of backwash orifices include: a first backwash orifice, which is arranged to discharge backwash water at a first area of ​​the filter; and a second backwash orifice, which is arranged to discharge backwash water at a second area of ​​the filter that is different from the first area, wherein the first area is closer to the rotation point than the second area, wherein the second backwash orifice discharges the backwash water at the second area, and the first backwash orifice discharges the backwash water at the first area so that the second area experiences a higher flow rate than the first area.

[0031] Clause 18: The method of Clause 17, wherein the solid-liquid separation system is a wastewater treatment system, wherein the solid-liquid stream is a wastewater stream or a mixed liquor stream of a secondary biological treatment system, the solid component is a sludge component, and the filtrate component is filtered water.

[0032] Clause 19: The method of Clause 18, further comprising: collecting at least a portion of the layer of sludge components removed from the surface; and removing at least a portion of the collected layer of sludge components from a tank in which the wastewater treatment system is disposed.

[0033] Clause 20: The method of clause 18 or 19, further comprising: arranging the rotary filter in a pool; filling the pool with wastewater; rotating the filter to separate the filtrate component from the wastewater, wherein the filtrate component includes filtered water; and removing the filtered water from the pool.

[0034] Clause 21: A method as described in any of clauses 17 to 20, wherein the first area and the second area partially overlap, so that the first backwash orifice discharges the backwash water at the overlapping portion of the first area and the second area and / or the second backwash orifice discharges the backwash water at the overlapping portion of the first area and the second area.

[0035] Clause 22: The method of any one of clauses 17 to 21, wherein the slope of a line representing backwash intensity as a function of distance from the rotation point of the rotary filter is greater than or equal to -2 liters / min / m 3 , such as greater than or equal to -1 liter / min / m 3 , greater than or equal to 0 liters / min / m 3 , greater than or equal to 1 liter / min / m 3 , or greater than or equal to 2 liters / min / m 3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a schematic diagram of a wastewater treatment system according to some non-limiting embodiments or aspects;

[0037] Figure 2 is a schematic diagram of a wastewater treatment system according to some non-limiting embodiments or aspects;

[0038] Figure 3 is a partial cross-sectional view of a filter device disposed in a wastewater tank according to some non-limiting embodiments or aspects;

[0039] Figure 4 is a schematic diagram of a filter device according to some non-limiting embodiments or aspects;

[0040] Figure 5 is a schematic diagram of a filter element according to some non-limiting embodiments or aspects;

[0041] Figure 6 is a cross-sectional view of a filter device in a wastewater treatment system according to some non-limiting embodiments or aspects;

[0042] Figure 7is a cross-sectional view of a plurality of oppositely facing liquid permeable filter elements separated by gaps, according to some non-limiting embodiments or aspects;

[0043] Figure 8 is a schematic diagram of a backwash tube having an orifice for discharging backwash water to create at least one overlap region of a filter element according to some non-limiting embodiments or aspects;

[0044] Figure 9 is a schematic diagram of a circular filter device having four ports at which backwash water is directed, according to some non-limiting embodiments or aspects;

[0045] Figure 10 is a schematic diagram of a solid-liquid processing unit according to some non-limiting embodiments or aspects; and

[0046] Figure 11 is the backwash water flow intensity (L / min / m2) as a function of distance from the rotation point of the rotary filter of Example 17 according to some non-limiting embodiments or aspects. 2 ) curve graph. DETAILED DESCRIPTION

[0047] For the purposes of the following description, the terms "upper," "lower," "right," "left," "vertical," "horizontal," "top," "bottom," "lateral," "longitudinal," and their derivatives shall be relative to the present invention as it is oriented in the drawings. However, it should be understood that the present invention may employ numerous alternative variations and step sequences, except where expressly indicated to the contrary. It should also be understood that the specific devices and processes illustrated in the drawings and described in the following specification are merely exemplary embodiments of the present invention. Accordingly, specific dimensions and other physical characteristics associated with the embodiments disclosed herein should not be considered limiting.

[0048] Furthermore, it should be understood that any numerical range recited herein is intended to include all subranges subsumed therein. For example, a range of "1 to 10" is intended to include all subranges between the recited minimum value of 1 and the recited maximum value of 10 (inclusive), i.e., having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0049] In this application, the use of the singular includes the plural and the plural encompasses the singular, unless otherwise specifically stated. In addition, in this application, the use of "or" means "and / or" unless otherwise specifically stated, even though "and / or" may be explicitly used in certain circumstances. In addition, in this application, the use of "a" or "an" means "at least one" unless otherwise specifically stated.

[0050] The present disclosure relates to a solid-liquid separation system comprising: a rotary filter configured to separate a solid-liquid flow into a filtrate component and a solid component, wherein the rotary filter has a rotation point and a circumference, the rotary filter rotates around the rotation point, and the circumference defines an end of the filter; and a plurality of backwash orifices comprising: a first backwash orifice, the first backwash orifice being arranged to discharge backwash water at a first region of the filter; and a second backwash orifice, the second backwash orifice being arranged to discharge backwash water at a second region of the filter that is different from the first region, wherein the first region is closer to the rotation point than the second region, wherein the second backwash orifice discharges the backwash water at the second region, and the first backwash orifice discharges the backwash water at the first region so that the second region experiences a higher flow rate than the first region.

[0051] refer to Figure 1 , a system 2 for treating a solid-liquid flow is shown. The solid-liquid flow will be discussed primarily in the context of a wastewater flow, but other types of solid-liquid flows are also within the scope of the present disclosure. The wastewater flow can produce a slurry that can be reused as a fuel in a waste to energy process, as well as a clean water filtrate comprising filtered water. Contaminated water 4 can be provided to a treatment area 6 from a contaminated water source. The contaminated water 4 is typically supplied to the treatment area 6 from an underground supply infrastructure, which is common in many water treatment systems. The infrastructure and its corresponding pipe network can be reused, requiring only minor upgrades to the pumping stations used for the system described herein. Other non-limiting examples of contaminated water sources include municipal sources, industrial sources, and / or agricultural sources, such as municipal wastewater.

[0052] Once the contaminated water 4 enters the treatment zone 6, the contaminated water 4 may undergo various processes. The treatment zone 6 can perform various physical, chemical and / or biological treatment processes. For example, the contaminated water 4 may undergo coarse screening to remove pollutants with a size of 20 mm or more, and then undergo fine screening to remove pollutants with a size of 6 mm or more. Additional processes may include fat, oil and / or grease removal. The gravel, sand and other pollutants removed from the contaminated water 4 in the treatment zone 6 can be disposed of by any conventional means, such as in a landfill. The treatment zone 6 can perform biological processes, including aerobic COD (chemical oxygen demand) removal, nitrification, denitrification, anoxic zones and combinations thereof. The treatment zone 6 can perform purification processes. The treatment zone may include various recycling processes, such as sludge return and / or mixed liquor return.

[0053] The liquid stream exiting the treatment zone 6 can be considered pre-treated sewage and / or wastewater 8, which is free of large debris and contaminants but still contains dissolved organic matter, inorganic matter, and suspended solids. The liquid stream exiting the treatment zone 6 is referred to herein as wastewater 8. The wastewater 8 may contain varying amounts of dissolved and / or suspended solids.

[0054] Wastewater 8 can be industrial or municipal and can include material less than 20 mm in size. For the systems and processes of the present invention, it can be advantageous to have a range of organic material contaminants (measured as COD, BOD, and TKN) in the wastewater 8, as well as a certain amount of total suspended solids (TSS). The systems and processes according to the present disclosure can treat a wide variety of organic contaminants in water, including the most complex industrial wastewaters.

[0055] The system 2 may include a wastewater tank 22 in which (as a non-limiting example) a biological process may be performed, which may include aerobic COD (chemical oxygen demand) removal, nitrification, denitrification, anoxic zones, and combinations thereof. The system 2 may include a filter device 20, which includes at least one liquid permeable filter element 40, such as a plurality of liquid permeable filter elements 40. The wastewater tank 22 may be any object configured to hold a certain volume of liquid. The at least one liquid permeable filter element 40 may include a filter screen. The filter screen may include stainless steel, polyester, nylon, polytetrafluoroethylene (PTFE, such as Teflon), polyvinylidene fluoride (PVDF) and / or any other suitable material. The material of the filter screen may be a material that is chemically resistant and / or inert to corrosion caused by the wastewater 8. The filter device 20 may have any shape known in the art. For example, the filter device 20 may have a circular or rectangular cross-section, such as Figures 1 to 2 As shown. The filter device 20 may include a single fixed liquid-permeable filter element 40. The filter device 20 may include a plurality of liquid-permeable filter elements 40. At least one liquid-permeable filter element 40 includes a first side 84 and a second side 86 opposite the first side 84. In a solid-liquid separation system, the first side 84 (e.g., the dirty side) may be the side on which a solid-liquid stream (e.g., a secondary biologically treated wastewater stream or a mixed liquor stream) is incident, and the second side 86 (e.g., the clean side) may be the side from which a filtrate (e.g., filtered water) is emitted. The solid component (e.g., sludge component) of the solid-liquid stream may be retained on the first side 84 and blocked by the filter element 40.

[0056] For example, the filter device 20 can be in the form of a disk or cartridge. If the filter device 20 is a disk or cartridge, the disk or cartridge can be rotated to facilitate the liquid to penetrate the filter element 40 for filtration, such as Figure 2If the filter device 20 is a disk or cartridge, the first side 84 of the disk or cartridge may be the outer surface of the filter cake layer 36 in which the sludge components are formed, while the second side 86 is the inner surface of the disk or cartridge and is contained within the disk or cartridge. Figure 2 During the rotation of the disc or drum, pressure from the wastewater 8 assists in its filtration, thereby producing a filter cake layer 36 on the first side 84 of the disc or drum. The filtrate 26 can be collected and transferred to the exterior of the filter device 20 by a transport device such as a pump and a transfer tube.

[0057] The system may include a plurality of interconnected wastewater tanks 22 , each containing at least one filter device 20 .

[0058] In the wastewater tank 22, there may be a height difference between the side of the liquid permeable filter element 40 that includes the wastewater 8 and the side of the at least one liquid permeable filter element 40 that includes the filtrate 26. Figures 1 to 3 As can be seen, a level 28 of the wastewater 8 in the wastewater sump 22 is provided and is higher than a level 38 of the filtrate 26 in the wastewater sump 22. The "filtrate" 26 is the wastewater 8 after it has been filtered by the at least one liquid-permeable filter element 40, thereby removing filterable solids from the wastewater 8. This height difference is typically about 25 cm or 0.025 bar. This height difference can help maintain continuous filtration of the wastewater 8 through the at least one liquid-permeable filter element 40. The filterable solids can be continuously deposited on the first side 84 of the at least one liquid-permeable filter element 40 of the filter device 20, thereby creating a filter cake layer 36 of filterable solids, the thickness of which increases as more filterable solids are deposited.

[0059] The at least one liquid-permeable filter element 40 may be sprayed with a liquid, such as the filtrate 26, to clean or assist in removing a filter cake layer 36 from the first side 84 of the at least one liquid-permeable filter element 40, the filter cake layer 36 being formed by deposition of filterable solids onto the first side 84 of the at least one liquid-permeable filter element 40.

[0060] For example, reference Figure 3 , the system may include a backwash system including at least one orifice configured to discharge a spray of fluid (e.g., backwash water) in the direction of the at least one liquid-permeable filter element 40. For example, the system may include at least one second orifice (backwash orifice) 48a, 48b that discharges a spray of fluid 50 at the second side 86 of the filter element 40, through the filter element 40, and toward the first side 84 of the at least one liquid-permeable filter element 40 to remove and / or assist in removing a filter cake layer 36 formed on the first side 84 of the at least one liquid-permeable filter element 40. Figure 3 The filter cake layer 36 is shown in its form adhered to the first side as an adhered filter cake layer 36i, and after being removed from the first side 84 as a removed filter cake layer 36ii when being reintroduced into the wastewater 8. The system may include at least one first orifice (surface cleaning orifice) 52 that discharges a spray 54 of fluid at the first side 84 of the liquid-permeable filter element 40. The fluid provided by the first orifice 52 and / or the second orifice 48a, 48b can be any liquid known in the art. For example, the fluid provided by the first orifice 52 and / or the second orifice 48a, 48b can be a liquid, such as a portion of the filtrate 26. Alternatively, the fluid provided by the first orifice 52 and / or the second orifice 48a, 48b can be a gas. The orifices 52, 48a, 48b can be made of stainless steel. The orifices 52, 48a, 48b can be made of plastic.

[0061] With respect to the rotary filter device 20, the rotary filter device 20 may be rotated at 0.1 to 20 rpm, such as 0.1 to 3 rpm, 0.1 to 2.5 rpm, or 0.1 to 1.0 rpm, to additionally assist in depositing the filterable solids on the liquid permeable filter element 40 of the rotary filter device 20. The filter cake layer 36 may deposit, grow, and thicken over the time it takes for the rotary filter device 20 to rotate once.

[0062] The at least one liquid permeable filter element 40 of the filter device 20 can remove suspended filterable solids from the wastewater 8, thereby producing a clarified liquid filtrate 26. The filter cake layer 36 can remain on the first side 84 of the at least one liquid permeable filter element 40 until removed.

[0063] The at least one liquid permeable filter element 40 may have a specified pore size. For example, in contrast to membrane filters, which typically have pore sizes greater than 0.1 μm, the at least one liquid permeable filter element 40 may have a pore size in the range of 1 to 40 μm, such as 2 to 30 μm, or less than 20 μm.

[0064] The filter device 20 may have a flux greater than 200 L / m across the at least one liquid permeable filter element 40. 2 h, or greater than 500L / m 2 h, or greater than 1,000 L / m 2 h. The filter device 20 may have a flux of up to 5,000 L / m across at least one liquid permeable filter element 40 2 h, or up to 4,000 L / m 2 h, or up to 3,000 L / m 2 h. This is a low energy solution.

[0065] The filter device 20 can operate within wastewater 8. The wastewater 8 can travel through the filter cake layer 36 and the liquid-permeable filter elements 40 and be collected as filtrate 26 on the other side of the liquid-permeable filter elements 40, which can then be transferred to the exterior of the filter device 20. The filter cake layer 36 deposited on the first side 84 of the liquid-permeable filter elements 40 of the filter device 20 can be removed by backwashing the second side 86 of the liquid-permeable filter elements 40. For example, water, such as the filtrate 26, can be applied to the second side 86 of at least one liquid-permeable filter element 40 from the second orifices 48a, 48b, causing the liquid to pass through the at least one liquid-permeable filter element 40 and flow toward the first side 84 of the at least one liquid-permeable filter element 40, thereby allowing the filter cake layer 36 to be more easily removed from the first side 84 of the liquid-permeable filter element 40.

[0066] The filter cake layer 36 can be removed from the first side 84 of the liquid-permeable filter element 40 and returned to the wastewater 8, where the filter cake layer 36 can be combined with a quantity of the wastewater 8 to produce the slurry 30. The filter device 20 can operate with a TSS content of at least 200 mg / L, or at least 5,000 mg / L, or at least 10,000 mg / L in the wastewater 8. The filter device 20 can operate with a TSS content of up to 50,000 mg / L, or up to 35,000 mg / L, or up to 20,000 mg / L in the wastewater 8. For example, the filter device 20 can operate with a TSS content of the wastewater 8 in the range of 10,000-20,000 mg / L.

[0067] For example, the spin filter device 20 can be implemented at the TSS content levels described. For example, the spin filter device 20 can include at least one liquid-permeable filter element 40, the at least one liquid-permeable filter element 40 including a first side 84 and a second side 86 opposite the first side 84. A filter cake layer 36 formed by filtering the wastewater 8 can form on the first side 84 of the at least one liquid-permeable filter element 40. The wastewater 8 can be intentionally contaminated with the at least one liquid-permeable filter element 40, thereby forming the filter cake layer 36 on the first side 84 of the at least one liquid-permeable filter element 40 and also forming a filtrate 26 that passes through the at least one liquid-permeable filter element 40. A liquid, such as the filtrate 26, can be sprayed onto the at least one liquid-permeable filter element 40 to clear and / or assist in removing the filter cake layer 36 from the first side 84 of the liquid-permeable filter element 40. For example, the second orifices 48a, 48b can discharge a spray 50 of fluid onto the second side 86 of the at least one liquid-permeable filter element 40. The first orifice 52 can discharge a spray 54 of fluid at a first side 84 of the at least one liquid-permeable filter element 40. For example, the fluid provided by the first orifice 52 and / or the second orifices 48a, 48b can be a liquid, such as a portion of the filtrate 26. Alternatively, the fluid provided by the first orifice 52 and / or the second orifices 48a, 48b can be a gas. A portion of the first side 84 of the at least one liquid-permeable filter element 40 can be subjected to pressurized wastewater 8, wherein when the at least one liquid-permeable filter element 40 is in a first position at least partially submerged in the wastewater 8, the pressure across the portion of the first side 84 is greater than 0 and less than or equal to 5.9 kPa. In a second position, in which the at least one liquid-permeable filter element 40 is no longer submerged in the wastewater 8, the first side 84 of the at least one liquid-permeable filter element 40 is not subjected to pressurized wastewater 8, or is subjected to wastewater 8 at a lower pressure than in the first position. The rotary filter device 20 may include at least one second orifice 48a, 48b that directs at least one spray 50 of fluid at the second side 86 of the at least one liquid-permeable filter element 40 through the at least one liquid-permeable filter element 40 and toward the first side 84 of the at least one liquid-permeable filter element 40 to clean and / or assist in removing the filter cake layer 36. The first orifice 52 may discharge the spray 54 of fluid at the first side 84 of the at least one liquid-permeable filter element 40. For example, the fluid provided by the first orifice 52 and / or the second orifice 48a, 48b may be a liquid, such as a portion of the filtrate 26. Alternatively, the fluid provided by the first orifice 52 and / or the second orifice 48a, 48b may be a gas. Software and physical performance enhancers may also be implemented to increase the efficiency of the filter device 20.For example, the rotational speed and backwash parameters of the at least one liquid permeable filter element 40 may be operated at a lower intensity compared to the biological treatment process of the rotary filter device 20 .

[0068] The at least one liquid permeable filter element 40 of the filter device 20 may have an optimized pore size, such as a pore size in the range of 2 to 40 μm.

[0069] As previously stated, a filter cake layer 36 formed from filterable solids suspended in the wastewater 8 prior to filtration can be removed from the first side 84 of the at least one liquid-permeable filter element 40 and reintroduced into the wastewater 8 (see filter cake layer 36ii). Upon reintroduction into the wastewater 8, the filter cake layer 36 can combine with a quantity of the wastewater 8 to form a slurry 30. For example, backwashing the at least one liquid-permeable filter element 40 can assist in removing the filter cake layer 36 by applying a spray 50 of fluid from the second orifices 48a, 48b to the second side 86 of the at least one liquid-permeable filter element 40, thereby penetrating the at least one liquid-permeable filter element 40. Additionally or alternatively, the second orifices 48a, 48b can apply a spray 50 of gas to the second side 86 of the at least one liquid-permeable filter element 40. Once the filter cake layer 36 is separated from the first side 84 of the at least one liquid-permeable filter element 40, gravity can reintroduce the filter cake layer 36 into the wastewater 8, thereby forming a slurry 30.

[0070] The slurry 30 may be collected and removed from the wastewater pond 22 by any suitable process. For example, the slurry 30 may be removed by pumping the slurry 30 through a pipe to the waste-to-energy system 32. The slurry 30 may be removed from the wastewater pond 22 continuously (e.g., by overflow), or the slurry 30 may be periodically removed from the wastewater pond 22 by a batch process.

[0071] The filtrate 26 may also be removed from the wastewater pond 22 using a transport device.

[0072] refer to Figures 3 to 10 , illustrates a non-limiting embodiment or aspect of a backwash system for a solid-liquid separation system (e.g., a wastewater treatment system). The backwash system may include a filter device 20 having a liquid-permeable filter element 40. The filter element 40 may be configured to separate a solid-liquid stream into a filtrate 26 component and a solid component including a sludge component (filterable solids that previously formed a filter cake layer 36). The solid-liquid stream may include wastewater and / or a mixed liquor stream from a secondary biological treatment system. The filtrate 26 may include filtered water that is cleaner than the water component in the wastewater 8.

[0073] refer to Figures 4 and 5, the filter device 20 may be a rotary filter. The filter device 20 may rotate about a rotation point and may have a circumference defining its ends. The filter device 20 may rotate in a clockwise or counterclockwise direction. The filter device 20 may include filter elements 40a, 40b for filtering the wastewater 8. The filter device 20 may be a turntable 58 to rotate the filter elements 40a, 40b. The filter device 20 may include a single filter element 40, or a plurality of filter elements 40a, 40b. Figure 4 As shown in the non-limiting example of FIG, the filter device 20 may include a plurality of filter elements 40a, 40b.

[0074] refer to Figure 4 , shows a non-limiting example in which the filter device 20 is a rotating disk filter. The filter device 20 can be in the shape of a disk 58, including a plurality of filter elements 40a, 40b surrounding the area of ​​the disk 58. The disk 58 can be arranged along Figure 4 The disc 58 can be circular or substantially circular. Substantially circular means that the disc 58 has a relatively rounded circumference. Shapes that may be considered substantially circular in the context of the present disclosure include discs 58 that are circular, oval, at least pentagonal, at least hexagonal, or at least octagonal. In some non-limiting embodiments, the filter device 20 can have other shapes besides a circular disc, such as a square, rectangular, triangular, or any other suitable shape.

[0075] refer to Figure 4 , the rotating filter device 20 can be substantially vertical relative to the ground. Substantially vertical means that the rotating filter is within 30° of a line perpendicular to the ground, such as within 15°, within 10°, within 5° or within 0°.

[0076] Reference again Figures 4 and 5 Filter elements 40a, 40b may have a trapezoidal shape as shown, or any other suitable shape. Depending on the shape of disk 58 of the rotating filter device 20, the linear velocity of filter elements 40a, 40b may vary radially along disk 58. For example, a first region 80 of filter element 40a, closer to the center of disk 58, may have a lower linear velocity LV1 than a second region 82 of filter element 40a, radially farther from the center of disk 58, may have a lower linear velocity LV2. It will be appreciated that while the angular velocity may remain constant, the linear velocity may increase as one moves radially outward from the rotation point of disk 58. Due to the difference in linear velocity along the radial direction, it will be appreciated that backwash orifices discharging backwash water at the same flow rate at different radial regions of filter element 40a will discharge backwash water at different backwash intensities (also taking into account the area covered) on filter element 40a. Flow rate refers to the L / min of backwash water discharged from the backwash orifice, while backwash intensity refers to the L / min / m² of the area of ​​backwash water incident on filter element 40a.2 .

[0077] refer to Figure 5 The backwash system may include a plurality of backwash orifices (second orifices 48a, 48b) configured to discharge a spray 50a, 50b of backwash water from the filter element 40 (e.g., at the second side 86 (from Figure 3 )) to remove at least a portion of the filter cake layer 36 therefrom (not shown). The plurality of second backwash orifices 48a, 48b may include a first second orifice 48a and a second second orifice 48b, such as Figure 5 As shown. These second orifices 48a, 48b can be arranged to discharge backwash water sprays 50a, 50b at different areas of the filter element 40 (e.g., a first area 80 and a second area 82). These different areas 80, 82 may partially overlap or may not overlap. The first area 80 may be closer to the rotation point of the filter device 20 than the second area 82. The surface area of ​​the first area 80 may be smaller than the surface area of ​​the second area 82. Although two orifices, sprays, and areas are shown, it will be understood that any number of orifices, sprays, or areas may be used.

[0078] The first-second orifice 48a may discharge the backwash water spray 50a at a first flow rate at the first region 80, while the second-second orifice 48b may discharge the backwash water spray 50b at the second region 82 at a second flow rate different from the first flow rate. The first flow rate discharged by the first-second orifice 48a may be lower than the second flow rate discharged by the second-second orifice 48b. The second-second orifice 48b may discharge the backwash water at the second region 82, and the first-second orifice 48a may discharge the backwash water at the first region 80, so that the second region 82 is subjected to a higher backwash intensity (in L / min / m2) than the first region 80. 2 Contacting the second region 82 at a higher flow rate than the first region 80 helps ensure that the backwash process adequately cleans all regions 80, 82 of the filter element 40 in an energy-efficient manner.

[0079] Continue to refer Figure 5, the second-second orifice 48b is shown as being larger than the first-second orifice 48a to emphasize that the second-second orifice 48b discharges a higher flow rate in the second region 82 than in the first region 80. For example, the opening of the second-second orifice 48b may be larger than the opening of the first-second orifice 48a. It will be appreciated that if a higher backwash intensity is desired in the second region 82 as compared to the first region 80, the second-second orifice 48b will eject the backwash water spray 50b at a higher flow rate than the first-second orifice 48a because the linear velocity LV2 in the second region 82 is higher than the linear velocity LV1 in the first region 80 when the filter is rotated. In this way, the second-second orifice 48b in the second region 82 can cover a larger area than the area covered by the first-second orifice 48a in the first region 80 in the same amount of time. Although Figure 5 The non-limiting example in FIG shows two second orifices 48a, 48b, but it will be understood that more orifices can be used, and the arrangement of those second orifices 48a, 48b can be selected so as to have a higher backwash intensity in the second region 82 (further from the rotation point) than in the first region 80. Since larger orifices can be used in areas with a larger area to be cleaned, the pump used to pump the backwash water can operate at a lower pressure, thereby reducing energy consumption and thus reducing operating costs. This is in contrast to using a relatively smaller orifice for an area with a relatively larger area (which requires the pump to operate at a higher pressure and thus consumes more energy and has higher operating costs).

[0080] The second orifices 48a, 48b can be configured to have any size to achieve the flow rate required to meet at least the minimum backwash intensity. In one non-limiting example, the first second orifice 48a has an opening of 1.0 to 1.5 mm, while the second second orifice 48b has an opening of 1.5 to 2.0 mm, so that, assuming a constant water pressure, the first second orifice 48a discharges backwash water at a lower flow rate than the second second orifice 48b. In one non-limiting example, the first second orifice 48a has a flow rate starting from 1-2 L / min, while the second second orifice 48b has a flow rate starting from 2-4 L / min.

[0081] refer to Figure 3 and Figure 6 , the filter element 40 may include a layer of sludge components (e.g., filter cake layer 36) formed on a surface (e.g., a first side 84 thereof). The filter cake layer 36 on the first side 84 of the filter element 40 may be formed by passing the wastewater 8 along the filter element 40. Figure 684. The filter element 40 may be formed by flowing toward the first side 84 in the direction of flow 92 indicated in FIG. At least a portion of the water from the wastewater 8 may flow through the filter element 40 (inflowing through the first side 84 and outflowing through the second side 86) to form a filtrate 26 comprising filtered water. The filter element 40 may prevent at least a portion of the sludge components from permeating therethrough, causing the sludge components to adhere to the first side 84 to form a filter cake layer 36. Second orifices 48a, 48b (not shown) may be arranged to discharge backwash water at the filter cake layer 36 to remove at least a portion of the filter cake layer 36 from the first side 84. At least one second orifice 48a, 48b may discharge backwash water from the second side 86, which is in contact with the filtrate 26. Using the second orifice 48a, 48b to contact the opposing second side 86 may facilitate removal of the filter cake layer 36 from the first side 84 by allowing the backwash water to contact the filter cake layer 36 from the first side 84 at an interface between the backwash water and the first side 84 after permeating through the second side 86.

[0082] refer to Figure 7 , showing a non-limiting example of a filter device 20. The filter device 20 may include a plurality of oppositely facing filter elements 40a, 40b separated by a gap 88. The filter elements 40a, 40b may be enclosed in the filter device 20. The filter device 20 may include a first filter element 40a having a first side 84a and a second side 86a and a second filter element 40b having a first side 84b and a second side 86b. The first sides 84a, 84b may face in opposite directions and may be outer surfaces of the filter device 20 so that they are in contact with the solid-liquid flow. The second sides 86a, 86b may be inner surfaces of the filter device 20 so that they are in contact with the filtrate, and the second sides 86a, 86b may be separated by the gap 88. A backwash pipe 90 may be disposed in the gap 88 to carry backwash water to the plurality of second orifices 48a, 48b. The second orifices 48a, 48b may discharge a spray 50a, 50b of backwash water at the second side 86a, 86b to dislodge the filter cake layer 36a, 36b on the first side 84a, 84b.

[0083] refer to Figure 8 , shows a schematic diagram of a backwash pipe 90 having second backwash openings 48a, 48b for discharging backwash water at the second side 86 of the filter element 40. The backwash openings 48a, 48b may be provided directly through the same backwash pipe 90 at different vertical heights. It will be appreciated that more than Figure 8The two backwash orifices 48a and 48b shown can be directly perforated on the backwash pipe 90. The perforations can be perforated holes, perforated slots, etc. The backwash orifices 48a and 48b can include nozzles. The nozzles can be configured to control the spray angle, spray pattern, spray distribution, etc. The backwash orifices 48a and 48b can discharge backwash water on the second side 86 to form non-overlapping areas 94a and 94b and an overlapping area 96. In the overlapping area 96, the second side 86 may be impacted by the backwash water discharged from multiple backwash orifices 48a and 48b. In the non-overlapping areas 94a and 94b, the second side 86 may be impacted by the backwash water discharged from a single backwash orifice (48a and 48b, respectively). The backwash intensity in the overlapping area 96 can be higher than the backwash intensity in the adjacent non-overlapping areas 94a and 94b.

[0084] refer to Figure 9 , shows a non-limiting example of a rotating filter device 20 in the form of a cartridge 100, the filter having four orifices (not shown) for discharging backwash water at the filter device 20 (e.g., its filter element 40). The filter device 20 rotates in a clockwise direction as shown. The filter device 20 can rotate around a rotation point 98. The filter device 20 shown in this non-limiting example has four regions R1-R4, thereby forming a belt around the circular filter, and each region is in contact with the backwash water from a different orifice, each belt having a larger surface area moving away from the center (rotation point 98). As the filter device 20 rotates, the linear velocity LV1-LV4 in each region R1-R4 increases as the region becomes farther away from the rotation point 98.

[0085] In this non-limiting example, the first orifice has a 1.2 mm orifice for discharging backwash water at the first region R1. The second orifice has a 1.3 mm orifice for discharging backwash water at the second region R2. The third orifice has a 1.5 mm orifice for discharging backwash water at the third region R3. The fourth orifice has a 1.9 mm orifice for discharging backwash water at the fourth region R4. Regions 401-404 of the filter element 40 are shown, covered by orifices for discharging backwash water at regions R1-R4. Backwash water can flow to all four orifices at the same pressure. Therefore, the flow rate of backwash water discharged from the fourth orifice is higher than the flow rate of backwash water discharged from the third orifice, which is higher than the flow rate of backwash water discharged from the second orifice, which is higher than the flow rate of backwash water discharged from the first orifice. Filtrate flowing through regions R1 - R4 of filter element 40 may flow vertically downward and into cartridge 100 where it is collected and exits the system.

[0086] Continue to refer Figure 9, the backwash intensity experienced by areas farther from the rotation point 98 can be higher than that experienced by areas 98 closer to the rotation point 98. For example, the backwash intensity experienced by a portion of the fourth region R4 can be higher than the backwash intensity experienced by the third region R3. Having a higher backwash intensity at areas farther from the rotation point 98 can achieve better and more efficient cleaning of the filter device 20. For the filter device 20, the backwash intensity as a function of the distance from the rotation point 98 can be calculated. The filter device 20 can be designed with a backwash orifice that is configured and arranged so that the slope of the line representing the backwash intensity as a function of the distance from the rotation point 98 is greater than or equal to -2 liters / min / m 3 , such as greater than or equal to -1, greater than or equal to -0.5, greater than or equal to 0, greater than or equal to 0.2, greater than or equal to 0.5, greater than or equal to 1, or greater than or equal to 2. The line can be generated as a best fit line based on modeling the data points or reporting the backwash intensity at different distances from the rotation point 98. The best fit line can be generated using any statistical method known to those skilled in the art, such as by using the best fit line (e.g., trend line) function in Microsoft Excel.

[0087] refer to Figure 10 , showing a solid-liquid processing unit 102 according to some non-limiting embodiments or aspects. The unit 102 may include a plurality of filter devices 20a-20m as described herein. The unit 102 also includes a pump system comprising a backwash pump 104 and a pipe 106 in fluid communication with the filter 20a-20m. For example, the pipe 106 may be in fluid communication with the backwash pipe 90a-90m. The backwash pump 104 may be configured to pump backwash water through the pipe 106 and to the backwash pipe 90a-90m. The backwash water may be discharged from the backwash pipe 90a-90m through a plurality of orifices 48a-48n vertically arranged in each of the filter devices 20a-20m. Each orifice 48a-48n may be a hole formed in the backwash pipe 90a-90m from which backwash water may be discharged, or each orifice 48a-48n may include a nozzle, which may be a component separate from the backwash pipe 90a-90m, which discharges backwash water from the backwash pipe 90a-90m and includes an orifice from which backwash water may be discharged.

[0088] Continue to refer Figure 10The pressure of the backwash water pumped to each of the filter devices 20a-20m (e.g., through its backwash pipes 90a-90m) can be substantially uniform. Substantially uniform means that the flow rate of the backwash water flowing through the backwash pipe 90a of the first filter device 20a is within 25% of the flow rate of the backwash water flowing through the backwash pipe 90m of the mth filter device 20m or any other backwash pipes (e.g., 90b, 90c) in the unit 102, such as within 20%, within 15%, within 10%, or within 5%. The pressure of the backwash water in the backwash pipes 90a-90m can be in the range of 1-10 bar, such as 2-5 bar.

[0089] The present disclosure also relates to a method for cleaning a filter in a solid-liquid processing system. Figures 4 to 10 The method may include arranging a plurality of backwash orifices (e.g., backwash orifices 48a, 48b) to discharge backwash water at the rotating filter device 20. The rotating filter device 20 may have a rotation point 98 and a circumference about which the rotating filter device 20 rotates, the circumference defining the ends of the filter device 20. The filter element 40 of the filter device 20 may be configured to separate a solid-laden liquid stream (e.g., a wastewater stream) into a filtrate component (e.g., filtered water) and a solid component (e.g., a sludge component). The filter element 40 may include a layer of solid components on its surface. The method may include discharging backwash water from the plurality of backwash orifices 48a, 48b at the filter device 20 to remove at least a portion of the layer of solid components from the surface. The plurality of backwash orifices 48a, 48b may be arranged to discharge backwash water at a first region 80 and a second region 82 of the filter device 20, respectively, such that the second region 82 (further from the rotation point 98 of the filter device 20) experiences a higher backwash flow rate than the first region 80.

[0090] refer to Figure 4 and Figure 5 , the filter device 20 may be rotatable (e.g., as Figure 4 For example, the filter element 40 may be rotated such that the linear velocity LV1 in the first region 80 is lower than the linear velocity LV2 in the second region 82.

[0091] refer to Figure 3 and Figure 5 The method may further include arranging a plurality of second backwash apertures 48a, 48b on a second side 86 of the filter device 20, and discharging backwash water from at least one of the second backwash apertures 48a, 48b on the second side 86. The at least one first aperture 52 may discharge backwash water at the solid content on the first side 84.

[0092] Continue to refer Figure 3The method may include placing the filter device 20 in a wastewater sump 22 and filling the wastewater sump 22 with a solid-liquid stream (e.g., wastewater 8). The method may include separating a filtrate 26 from the solid-liquid stream by rotating the filter device 20, wherein the filtrate 26 comprises filtered water. The filtered water may be collected and removed from the wastewater sump 22. The method may include collecting a portion of the solid components (e.g., sludge components) removed from the surface of the filter element 40. The collected solid components may be removed from the wastewater sump 22 in which the filter device 20 is arranged.

[0093] Example

[0094] Examples 1-16

[0095] Comparative disk system

[0096] Two rotating disc filter systems (activated sludge filters) were equipped with multiple sets of backwash orifices. The first disc system (DS1) was the original design. The DS1 system had two 1 mm orifices installed at different radial distances from the disc center. The second disc system (DS2) was an optimized orifice design according to the present disclosure. DS2 also had two orifices installed at the same radial distance, but the orifice closer to the disc center had a 1.2 mm orifice, while the orifice farther from the disc center had a 1.7 mm orifice.

[0097] Both DS1 and DS2 were tested for wastewater treatment. Seven events were randomly selected over an approximately 10-day period to compare DS1 and DS2 based on their solids flux performance. Solids flux was calculated as flux multiplied by mixed liquor suspended solids (MLSS) concentration. Solids flux is a useful comparison metric because DS1 and DS2 may not operate at the same MLSS concentration, and previous testing has shown that flux is lower at higher MLSS concentrations.

[0098] Based on BW kWh energy / m 3 Water filter and mainly based on solid flux, 6 of the events showed that DS2 outperformed DS1, and 1 event showed that DS1 outperformed DS2. The detailed calculations are shown in the table.

[0099] Although DS1 and DS2 are similar systems, some unknown aspects of DS1 and DS2 may affect this comparison. Regardless of the backwash nozzle configuration, DS2 may inherently outperform DS1. To eliminate the inherent performance differences between DS1 and DS2 and make the comparison more convincing, the orifice design was changed.

[0100] During another 3-week period, DS2 was changed to the original orifice design with two 1 mm orifices. DS1 was changed to an optimized orifice design with two orifices of 1.2 mm and 1.7 mm. Tables 2 and 3 show this change and the results. Nine events were randomly selected during the time period to compare DS1 and DS2 based on solid flux performance. Seven of the events showed that DS1 outperformed DS2, and one event showed that DS2 and DS1 performed similarly. One event showed that DS2 outperformed DSL.

[0101] Thus, out of 16 events, 13 events showed that the system with the optimized orifice design outperformed the system without the optimized orifice design. 1 event showed that the system with the optimized orifice design and the system without the optimized orifice design performed similarly. 2 events showed that the system with the optimized orifice design did not perform as well as the system without the optimized orifice design.

[0102] Overall, it was found that systems using optimized orifice designs at different radial distances showed improved performance compared to systems using the same orifice size at different radial distances. Within each event, DS1 and DS2 consumed comparable backwash power. Tables 1-3 below show the relevant results.

[0103] Backwash energy conversion is calculated using the following formula: Backwash energy (kW) = [backwash flow rate (m 3 / h)*backwash pressure (Pa)] / 3.6×10^6

[0104] The specific backwash energy is calculated using the following formula: Specific backwash energy (kWh / m 3 )=backwash energy (kW) / filtrate flow rate (m 3 / h).

[0105] Table 1

[0106]

[0107]

[0108] Table 2

[0109]

[0110] Table 3

[0111]

[0112] Example 17

[0113] Measuring backwash intensity as a function of distance from the rotation point

[0114] A rotating disc filter is designed to include four nozzles of different sizes arranged between the disc's rotation point and the disc's edge. When the hydraulic pressure at the backwash arm is 5 bar, the nozzle at 593.8 mm above the rotation point has a diameter of 1.2 mm and a nozzle flow rate of 1.98 LPM. The second-closest nozzle at 711.9 mm above the rotation point has a nozzle diameter of 1.3 mm and a nozzle flow rate of 2.53 LPM. The third-closest nozzle at 833.2 mm above the rotation point has a nozzle diameter of 1.5 mm and a nozzle flow rate of 3.16 LPM. The farthest nozzle at 951.9 mm above the rotation point has a nozzle diameter of 1.9 mm and a nozzle flow rate of 4.98 LPM. Each nozzle has a spray angle of 75°, and the horizontal distance between the nozzle and the filter mesh penetration size is 62 mm.

[0115] Based on the properties and arrangement of this system, backwash intensity (“(I) Flow intensity [LPM / m”)”) is performed as a function of the distance from the rotation point of the rotary filter (“(radial) distance from the center of the disc [m]”). 2 ]”). Based on the calculation results, Microsoft Excel is used to generate graphical results, and the graphical results are Figure 11 The best fit line generated by Microsoft Excel for the data is represented by the formula y=0.22x+5.06, where the slope of the line representing the backwash intensity as a function of the distance from the rotation point of the rotary filter is greater than or equal to -2 liters / min / m 3 , which has been found to achieve improved cleaning of the filter while also reducing the energy consumption required to clean the filter (ie lower kWh consumption per cubic meter of filtrate produced).

[0116] It should be understood that, unless expressly stated otherwise, the present invention may adopt various alternative variations. It should also be understood that the specific devices illustrated in the drawings and described in the specification are merely exemplary embodiments of the present invention. Although the present invention is described in detail based on what is currently considered to be the most practical and preferred embodiments for illustrative purposes, it should be understood that such details are for illustrative purposes only, and the present invention is not limited to the disclosed embodiments, but is intended to cover modifications and equivalent arrangements that fall within its spirit and scope. For example, it should be understood that, for the present invention, one or more features of any embodiment may be combined with one or more features of any other embodiment, to the extent possible. The embodiments of the present invention described above in the context of preferred embodiments should not be considered to limit the embodiments of the present invention to all the details provided, as they may be modified and varied without departing from the spirit and scope of the embodiments of the present invention.

Claims

1. A solid-liquid separation system comprising: a rotary filter configured to separate a solids-laden liquid stream into a filtrate component and a solids component, wherein the rotary filter has a rotation point and a perimeter about which the rotary filter rotates, the perimeter defining ends of the filter; as well as a plurality of backwash apertures including: a first backwash aperture arranged to discharge backwash water at a first region of the filter; and a second backwash orifice arranged to discharge the backwash water at a second region of the filter different from the first region, wherein the first region is closer to the rotation point than the second region, wherein the second backwash orifice discharges the backwash water at the second region, and the first backwash orifice discharges the backwash water at the first region, such that the second region experiences a higher flow rate than the first region.

2. The solid-liquid separation system according to claim 1, wherein the first area and the second area partially overlap, so that the first backwash hole discharges the backwash water at the overlapping part of the first area and the second area and / or the second backwash hole discharges the backwash water at the overlapping part of the first area and the second area.

3. The solid-liquid separation system of claim 1 , wherein the rotary filter comprises a first side into which the solid-liquid stream is injected and a second side from which the filtrate component is emitted, wherein the plurality of backwash orifices discharge the backwash water at the second side.

4. The solid-liquid separation system according to claim 1, wherein the rotary filter includes a layer of the solid components formed on a surface, wherein the first backwash orifice and the second backwash orifice are arranged to discharge the backwash water at the layer of the solid components so as to remove at least a portion of the layer of the solid components from the surface.

5. The solid-liquid separation system according to claim 1 , wherein the slope of a line representing backwash intensity as a function of the distance from the rotation point of the rotary filter is greater than or equal to -2 liters / min / m 3 .

6. The solid-liquid separation system according to claim 1 , wherein the slope of a line representing backwash intensity as a function of the distance from the rotation point of the rotary filter is greater than or equal to −1 liter / min / m 3 .

7. The solid-liquid separation system according to claim 1 , wherein the slope of a line representing backwash intensity as a function of the distance from the rotation point of the rotary filter is greater than or equal to 0 liters / min / m 3 .

8. The solid-liquid separation system according to claim 1 , wherein the slope of a line representing backwash intensity as a function of the distance from the rotation point of the rotary filter is greater than or equal to 1 liter / min / m 3 .

9. The solid-liquid separation system according to claim 1 , wherein the slope of a line representing backwash intensity as a function of the distance from the rotation point of the rotary filter is greater than or equal to 2 liters / min / m 3 .

10. The solid-liquid separation system of claim 1, wherein the rotary filter is a rotating disk and / or wherein the rotary filter is substantially vertical. The solid-liquid separation system according to claim 1 , wherein the plurality of backwashing orifices are directly provided on the backwashing pipe.

12. The solid-liquid separation system of claim 1, wherein the solid-liquid separation system is a wastewater treatment system, wherein the solid-liquid stream is a wastewater stream or a mixed liquor stream of a secondary biological treatment system, the solid component is a sludge component, and the filtrate component is filtered water. 13 . The solid-liquid separation system according to claim 1 , wherein a linear velocity of the rotary filter in the first zone is lower than a linear velocity of the rotary filter in the second zone.

14. A solid-liquid processing unit comprising: A plurality of solid-liquid separation systems according to claim 1; and a pump system in fluid communication with the plurality of solid-liquid separation systems, The pump system is configured to pump backwash water to each of the plurality of solid-liquid separation systems.

15. The solid-liquid processing unit according to claim 14, wherein the flow rate of the backwash water flowing to the first solid-liquid separation system among the multiple solid-liquid separation systems is within a deviation of 25% relative to the flow rate of the backwash water flowing to the second solid-liquid separation system among the multiple solid-liquid separation systems.

16. A method for cleaning a solid-liquid separation system, comprising: disposing a plurality of backwash orifices for discharging backwash water at a rotary filter configured to separate a solids-laden liquid stream into a filtrate component and a solid component, wherein the rotary filter includes a layer of the solid component formed on a surface, wherein the rotary filter has a rotation point about which the rotary filter rotates and a perimeter defining an end of the filter; as well as discharging the backwash water from the plurality of backwash orifices at the filter to clear at least a portion of the layer of solid components from the surface, wherein the plurality of backwash apertures comprises: a first backwash aperture arranged to discharge backwash water at a first region of the filter; and a second backwash orifice arranged to discharge the backwash water at a second region of the filter different from the first region, wherein the first region is closer to the rotation point than the second region, wherein the second backwash orifice discharges the backwash water at the second region, and the first backwash orifice discharges the backwash water at the first region, such that the second region experiences a higher flow rate than the first region.

17. The method according to claim 16, wherein the first area and the second area partially overlap, so that the first backwash hole discharges the backwash water at the overlapping portion of the first area and the second area and / or the second backwash hole discharges the backwash water at the overlapping portion of the first area and the second area.

18. The method according to claim 16, wherein the slope of a line representing the backwash intensity as a function of the distance from the rotation point of the rotary filter is greater than or equal to -2 liters / min / m 3 .

19. The method according to claim 16, wherein the slope of a line representing backwash intensity as a function of distance from the rotation point of the rotary filter is greater than or equal to -1 liter / min / m 3 .

20. The method of claim 16, wherein the slope of a line representing backwash intensity as a function of distance from the rotation point of the rotary filter is greater than or equal to 0 liters / min / m 3 .

21. The method of claim 16, wherein the slope of a line representing backwash intensity as a function of distance from the rotation point of the rotary filter is greater than or equal to 1 liter / min / m 3 .

22. The method of claim 16, wherein the slope of a line representing backwash intensity as a function of distance from the rotation point of the rotary filter is greater than or equal to 2 liters / min / m 3 .

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