Solids and liquids separator

Abstract

A water treatment device comprising a main inlet for receiving a flow of water into the water treatment device and a main outlet for the discharge of water from the water treatment device. A water diverter is disposed downstream of the main inlet and configured to preferentially divert water from the main inlet through a treatment circuit for treatment and to return treated water to the main outlet for discharge. The treatment circuit comprises a lamella clarifier and a sump for the collection of solid particles. The water diverter is further configured to divert at least a portion of the flow of water into the device through a bypass circuit when an operational parameter determined by the flow of water into the treatment device exceeds a predetermined level. The bypass circuit allows water entering the device from the main inlet to bypass the treatment circuit and to be diverted to the main outlet for discharge.

Description

SOLIDS AND LIQUIDS SEPARATORField

[0001] The present invention relates to a water treatment separator device for separating solids and liquids, and more particularly to a water treatment device for capturing and retaining pollutants in stormwater runoff.Background

[0002] In stormwater drainage networks, the removal of debris from stormwater before it is discharged into natural water bodies such as rivers, lakes, and bays has become increasingly important. Floating debris can accumulate on riverbanks and shorelines, while heavier debris sinks to the bottom, smothering aquatic life and causing siltation. These materials severely degrade the environment, and modem sociological issues have introduced hazardous waste like syringes, posing additional public health risks. Accordingly, many governments and regulators now set standards regarding the discharge of stormwater runoff into oceans, rivers, lakes, and bays; mandating minimal pollutant removal rates into these sensitive receiving environments.

[0003] Historically, separators and pollutants traps that were used to capture gross pollutants such as litter, organic matter like leaves and sticks, and coarse sediments used meshes, grates, or similar structures as the primary capture mechanism. Sometimes however, these methods faced challenges such as blockages, which in turn could cause a loss of energy from the flow and resulting in raised water levels in the upstream drainage system. This has the potential to cause upstream flooding.

[0004] A particular issue arises due to the need for the device to work under a wide range of flow through rates.

[0005] Further, some separators and pollutants traps are configured in an offline arrangement, where they would use walls or similar barriers across pipelines to divert flow into the device. These obstructions can cause water to back up during high flows, increasing upstream water levels and cause local flooding. Additionally, if not regularly cleaned, debris and litter can accumulate, blocking the pipeline and leading to similar issues. Furthermore, these issues may be exacerbated in some stormwater treatment devices which rely on moving parts to regulateflow. The moving parts may be rendered ineffective due to accumulation or lodgement of debris requiring additional maintenance and leading to increased risk of blockages.

[0006] It is an object of the present invention to substantially overcome, or at least ameliorate, one or more disadvantages of existing arrangements, or to at least provide the public with a useful choice.Summary of Invention

[0007] In one aspect the invention provides a water treatment device comprising: a main inlet for receiving a flow of water into the water treatment device; a main outlet for the discharge of water from the water treatment device; a treatment circuit for receiving water to be treated and returning treated water to the main outlet for discharge, said treatment circuit comprising a lamella clarifier and a sump for the collection of solid particles; a bypass circuit allowing water entering the device from the main inlet to bypass the treatment circuit and to be diverted to the main outlet for discharge; a water diverter downstream of the main inlet configured to preferentially divert water from the main inlet through the treatment circuit and to divert at least a portion of the flow of water into the device through the bypass circuit when an operational parameter determined by the flow of water into the treatment device exceeds a predetermined level.

[0008] Preferably, the predetermined parameter is associated with or includes a flow rate of water into the device. Alternatively, the predetermined parameter is associated with or includes a flow rate of water through the treatment circuit such as a maximum treatment flow rate (TFR) of the treatment circuit.

[0010] Preferably, the diverter comprises a treatment inlet for directing water into the treatment circuit from the main inlet and a bypass inlet for directing water into the bypass circuit from the main inlet.

[0011] Preferably, at least a portion of the treatment inlet is disposed below a lower extremity of the bypass inlet.

[0012] Preferably, the treatment inlet and the bypass inlet are disposed within an inlet chamber for receiving water from the main inlet and wherein the predetermined parameter is a bypass height of a water level in the inlet chamber.

[0013] Preferably, the bypass height is determined by a lower extremity of the bypass inlet.

[0014] Preferably, the bypass inlet includes a weir adapted to prevent water passing through the bypass inlet when the water level in the inlet chamber is below said bypass height.

[0015] Preferably, the weir is a includes a weir crest set at the lower extremity of the bypass inlet.

[0016] Preferably, the weir is a broad crested weir having a gradual upward sloping entry extending from a floor of the inlet chamber to a smooth waveform crest and an outlet ramp sloping gradually downwardly toward the main exit.

[0017] Preferably, the treatment circuit includes a lamella clarifier includes a lamella coalescing stack. Preferably the lamella coalescing stack comprises a inclined lamella tube settler and / or inclined lamella plate settler.

[0018] Preferably, the lamella coalescing stack is disposed in a treatment chamber.

[0019] Preferably, the lamella coalescing stack comprises an array of closely spaced parallel channels angled relative to the flow direction of water in the treatment chamber.

[0020] Preferably, the device further includes a baffle wall dividing the treatment chamber from a floatables storage zone.

[0021] Preferably, the device further includes a flushing system for flushing the device of debris.

[0022] Preferably, the flushing system comprises series of conduits and nozzles directing jets of water to flush portions of the treatment circuit for cleaning.

[0023] In another aspect, the invention provides a water treatment device comprising: a main inlet for receiving a flow of water into the water treatment device; a main outlet for the discharge of water from the water treatment device; a treatment circuit for receiving water to be treated and returning treated water to the main outlet for discharge, said treatment circuit comprising: a lamella clarifier; and a sump for the collection of solid particles; a bypass circuit allowing water entering the device from the main inlet to bypass the treatment circuit and to be diverted to the main outlet for discharge; a water diverter downstream of the main inlet comprising an inlet chamber or area having a treatment inlet for directing water into the treatment circuit from the main inlet and a bypass inlet for directing water into the bypass circuit from the main inlet; and wherein at least a portion of the treatment inlet is disposed below a lower extremity of the bypass inlet.

[0024] Preferably, the inlet chamber includes a weir adapted to prevent water passing through the bypass inlet when a water level in the inlet chamber is below a predetermined level and allow at least a proportion of the water in the inlet chamber into the bypass circuit via the bypass inlet when the water level in the inlet chamber is above, a predetermined level.

[0025] Preferably, predetermined level is set by the lower extremity of the bypass inlet.Brief Description of Drawings

[0026] A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0027] Fig. l is a perspective view of an embodiment of a water treatment device in accordance with the invention wherein a top cover is removed;

[0028] Fig. 2 is a front view of the device shown in Fig. 1;

[0029] Fig. 3 is a side view of the device shown in Fig. 1;

[0030] Fig. 4 is a top view of the device shown in Fig. 1;

[0031] Fig. 5 is a sectional perspective view of the water treatment device of Fig. 1 taken along section plane A-A of Fig. 2;

[0032] Fig. 6 is a sectional perspective view of the water treatment device of Fig. 1 taken along section plane B-B of Fig. 2;

[0033] Fig. 7 is a sectional side view of the water treatment device of Fig. 1 taken along section plane C-C of Fig. 2;

[0034] Fig. 8 is a sectional front view of the water treatment device of Fig. 1 taken along section plane D-D of Fig. 4;

[0035] Fig. 9 is a perspective cutaway and exploded view of the water treatment device shown in Fig. 1;

[0036] Fig. 10 is a perspective view of an inlet assembly of the water treatment device shown in Fig. 1;

[0037] Fig. 11 is a perspective view of the inlet assembly shown in Fig. 10 annotated to show the flow of water entering the treatment circuit and descending under the baffle wall;

[0038] Fig. 12 is a perspective view of the inlet assembly shown in Fig. 10 excluding the baffle wall annotated to show the flow of water entering and leaving the treatment and bypass circuits;

[0039] Fig. 13 is a perspective cutaway view of the main chamber of the water treatment device and lamella clarifier shown in Fig. 1 displaying the flush system;

[0040] Fig. 14 is a perspective partial view of the lamella clarifier stack and

[0041] Fig. 15 is a detail partial front view of the lamella clarifier stack.Description of Embodiments

[0042] There is disclosed a water treatment device for separating solids and liquids, and more particularly to a water treatment device for capturing and retaining pollutants in stormwater runoff.

[0043] Figs. 1 - 4 show respective perspective, front side and top views of a water treatment device 1 in accordance with the invention. Figs. 5 & 6 are sectional perspective views from the left and right sides of the device 1 respectively, in which the near side panel has been excluded to allow for inspection of the various internal parts of the device 1. The water treatment device 1 comprises a main inlet 10 for receiving a flow of water into an inlet area or chamber 12 of the water treatment device 1 and a main outlet 14 for the discharge of water from the water treatment device 1. Water from the main inlet 10 may be directed to the main outlet 14 either through a treatment circuit via which the water is treated before being discharged from the main outlet 14, or a bypass circuit which bypasses the treatment circuit so that untreated water flows directly from the main inlet 10 to the main outlet 14 and is discharged from the device without treatment. The device 1 includes a water diverter 16 downstream of the main inlet 10 configured to preferentially divert water from the main inlet 10 through the treatment circuit and to divert at least a portion of the flow of water into the device through the bypass circuit when an operational parameter determined by the flow of water into the inlet chamber 12 exceeds a predetermined level. In the Figures, and particularly Figures 5, 6, 11 & 12, white arrows indicate the flow of water flowing through the main inlet 10 and being diverted through the treatment circuit, while black arrows show the flow of water being allowed to bypass the treatment circuit via the bypass circuit.

[0044] The treatment circuit includes a treatment chamber 18 for receiving water to be filtered, a lamella clarifier 19 through which the water is passed before being returned to the main outlet 14 for discharge, a sump 20 for the collection of solid particles and a floatable materials zone 21 for the collection of floatable materials. In this embodiment the lamella clarifier 19 includes a lamella coalescing stack 22 which encourages particles suspended in the water to fall into the sump 20 where they are retained for collection.

[0045] Under low flow rate conditions, where the flow rate of water entering the device 1 through the main inlet 10 is low or moderate so as to be at or below a maximum flow rate capacity of the treatment circuit, water from the main inlet 10 is diverted solely or substantially solely through the treatment circuit. However, under high flow rate conditions, such as during downpours where the flow rate of water entering the device 1 through the main inlet 10 is high and exceeds a maximum treatment flow rate (TFR) of the treatment circuit, at least a portion of water entering the main inlet 10 is diverted and allowed to bypass the treatment circuit by means of the bypass circuit. The maximum treatment flow rate (TFR) of the treatment circuit is in partdetermined by the lamella clarifier 19 which requires controlled water flow rate, or velocity for effective treatment.

[0046] Diversion of water between the treatment and bypass circuits is controlled by the diverter 16 which includes the inlet area or chamber 12 and a treatment inlet 26 for directing water into the treatment circuit and a bypass inlet 28 for directing water into the bypass circuit from the inlet area or chamber 12. As seen in Fig. 7, at least a portion of the treatment inlet 26 is disposed below a lower extremity 30 of the bypass inlet 28 such that water entering the device 1 from the main inlet 10 preferentially flows to the treatment inlet 26 due to it being relatively lower than the bypass outlet 28. Furthermore, the treatment outlet 26 is preferable set in alignment with, or to extend below a floor 32 of the inlet chamber 12 so that water cannot accumulate in the inlet chamber 12. Under high flow rate conditions, where the flow rate of water entering the device 1 through the main inlet 10 exceeds the maximum treatment flow rate (TFR) of the treatment circuit, the level of the water in the inlet chamber 12 rises until it is above the level of the lower extremity 30 of the bypass inlet 28 and may flow into the bypass circuit. Accordingly, the operational parameter is the level of the water in the inlet chamber 12 which is governed by the relative flow rate of water into the inlet chamber 12 and flow rate of water through the treatment circuit while the predetermined level whereby water is diverted to the bypass circuit is set by a bypass height h according to the lower extremity 30 of the bypass inlet 28. In this embodiment the bypass height is measured with respect to the floor level of the inlet chamber 12 which is level with the lower extremity of the treatment inlet 26.

[0047] In this embodiment the diverter 16 includes a weir 36 having a weir crest 38 forming the lower extremity 30 of the bypass inlet 28 and thereby defining the bypass height h. The weir 36 is a broad crested weir having a gradual upward sloping entry 40 extending from the floor 32 of the inlet chamber 12 to a smooth waveform crest 38 and an outlet ramp 42 sloping gradually downwardly toward the main outlet 14 providing an outlet passage for water bypassing the treatment circuit. The bypass inlet 28 is disposed generally opposite the main inlet 10 to minimize lateral diversion of high flow rate water entering the inlet chamber 12 which together with the smooth, broad crested weir 36 provides a bypass path over the weir from the inlet 10 to the outlet 14 to minimise turbulence and resistance to flow through the device 1 at high inlet flow rates thereby reducing backup of the drainage network to which the device is installed.

[0048] The figures show an embodiment of a water treatment device 1 including a main body 100 having an internal main chamber 102, an inlet chamber insert 104 disposed in the main chamber 102 separating the inlet chamber 12 from a treatment chamber 106 below, a baffle wall 108, a clarifier assembly 110 including the lamellar clarifier 19, and a flushing system.

[0049] In the depicted embodiment, the main body 100 is formed as a generally rectangular box having a bottom wall 120, a pair of lateral side walls 122, 124 and front 126 and rear 128 side walls extending upwardly to an open top 130 providing access to the main chamber 102. A removable lid 132 or cover may be used to selectively close off the open top 130 or to provide access to the internal main chamber 102 for inspection and maintenance. A pair of oppositely disposed openings 132, 134 through respective front and rear side walls 126 and 128 are provided for accommodating the main inlet 10 and outlet 14. Typically, the device 1 is adapted to be at least partially buried so that the main inlet 10 and outlet 14 are below ground.

[0050] By way of example only, the main body 100 may have a wall thickness of between 150mm to 250mm and the main chamber may have a width of between 2,500mm to 4,300mm, a length of between 2,800mm to 5,500mm a height of between 2,500mm to 6,500mm, providing an internal volume of between 3,500 liters and 77,000 liters. It will be appreciated however that the volumetric capacity of the main chamber may be selected dependent on the corresponding inlet pipe diameter and anticipated flow rates of the application and flow capacity of the filter assembly. Alternatively, multiple separator devices may be plumbed in parallel to provide increased capacity.

[0051] The main body 100 and chamber 102 may alternatively take other suitable shape, for instance a square, rounded, round, oval or other complex shapes, for example. The main body 100 may be formed of a stainless-steel material, for example. Other suitable materials for the main body include but are not limited to concrete, plastics, or composite materials including reinforced cement, fiberglass or carbon fiber.

[0052] The main chamber 102 includes an upper portion 140 receiving the inlet chamber insert 104, and a lower portion 142 forming the treatment chamber 106 and sump 20 for the collection of solid particles. The openings 130, 132 for the main inlet 10 and main outlet 14 are positioned in the upper portion 140.

[0053] Ideally the shapes and dimensions of the device and the components within are selected to provide optimal flow rates to maintain operating efficiency of the treatment system and particularly to maintain the flow rate through the treatment circuit below the maximum treatment flow rate (TFR). Primarily the water diverter 16 and the height of the weir, together with clarifier assembly 110 including the lamellar clarifier 19 work in unison and combination to control the TFR. However other components such as the main inlet 10 which is typically of a circular cross section to be mated to a circular stormwater pipe, has a cross-sectional area (diameter in the case of a circular inlet) selected depending on the flow rate capacity of separator to control the velocity of the water passing into the inlet chamber.

[0054] The outlet is also of a circular cross section to be mated to a circular stormwater pipe for evacuating water. Typically, the main outlet 14 has a cross-sectional area (diameter in the case of a circular inlet) corresponding to the main inlet 10. With reference to Fig. 7, it can be seen that the main inlet 10 is disposed to be at least partially higher in its vertical alignment to the main outlet 14 to ensure hydraulic drainage through the device 1 from both the treatment circuit and bypass circuit. In some embodiments the device 1 may have multiple outlets for example, separate outlets for water from the treatment circuit and for water bypassing the treatment circuit.

[0055] In this embodiment the inlet chamber 12 is partially defined by the inlet chamber insert 104which is received in the upper portion of the main body. The inlet chamber insert 104 may be configured as a separate removable part and includes a bottom wall 150 extending from the main inlet 10 to the main outlet 14 providing a fluid barrier between the inlet chamber 12 and the lower treatment chamber 106 below, clarifier assembly 110 and sump 20 of the lower portion. As best seen in Figs. 6, 7 and 9, the bottom wall 150 of the inlet chamber insert 104 also forms the floor 32 of the inlet chamber 12, weir 36 and main outlet ramp 42. The crest 38 of the weir 36 defines the lower extremity 30 of the bypass inlet 28 from the inlet chamber 12 and splits the upper portion of the main body into the inlet chamber 12 at the upstream side and the main outlet ramp 42 downstream of the weir crest 36.

[0056] In this embodiment circular pipe connectors 152 and 154 are provided respectively forming the main inlet 10 and main outlet 14 enabling fluid connection of the device 1 to external upstream and downstream stormwater pipework respectively. The width of the inlet chamber 12 is sized to be larger than the diameter of the inlet pipe connector thereby providingan increase in the cross-sectional flow area for water as it enters the inlet chamber 12 thereby promoting a reduction in flow velocity.

[0057] Referring to Figs. 10 & 11, lateral sidewalls 156 and 158 extend along opposite sides of the inlet chamber insert 104 to control the flow of water entering the main inlet 10 and direct it toward the treatment and bypass inlets 26 and 28 respectively. The lateral side walls 156 and 158 may be integral with the bottom wall 150 or separate parts. In alternative embodiments at least one side edge of the bottom wall 150 sealingly abuts a lateral side of the main chamber to provide one of the lateral side walls thereby preventing water leaking from the inlet chamber into the lower portion of the main chamber.

[0058] With reference to Figs. 10 & 11, one side wall 156 includes an aperture 162 forward of the weir crest 38 2 forming the treatment inlet 36 from the inlet chamber 12. In this embodiment, this side wall 156 also extends downwardly into the lower portion of the main chamber 102 providing a partition or baffle wall 108 and forming a physical barrier within the lower portion 142. It will be noted that the baffle wall 108 is spaced from the side wall 122 of the main chamber 102 to provide a partition of the lower portion 142 into a floatables storage zone 21 and treatment chamber 106, and a passage 172 for water and debris carried by the water passing through the treatment inlet 26 to drop into the lower portion 142 of the main chamber 102. Furthermore, with reference to Figs. 5, 6 and 8, a lower edge 174 of the baffle wall 108 is vertically spaced above the main chamber floor 176 providing a passage for water and negatively or neutrally buoyant solids to migrate under the baffle wall 108 from the floatable storage zone 21 and into the treatment chamber 106. In normal operation, the water level in the main chamber 102 is level with the main outlet such that the lower edge 174 is submerged to retain positively buoyant floatable matter within the floatable storage zone 21.

[0059] The clarifier assembly 110 and lamella clarifier 19 are disposed in the treatment chamber, toward an upper portion thereof, below the inlet chamber and weir. The lamella clarifier 19 includes the lamella coalescing stack 22 of linear flat plates, corrugated plates, tubes, or channels which induce coalescing of neutrally buoyant materials.

[0060] The lamella clarifier 19 is designed to remove particulates from liquids. In one embodiment the lamella clarifier 19 is formed as a lamellar stack 22 or inclined plate settler (IPS) comprising an array of closely spaced parallel channels 182 angled relative to the upwardflow direction of water. Typically, the channels 182 are angled at an angle of around 60° to the vertical however angles between around 45° and 70° may also be effective.

[0061] As shown in Fig. 14, in this embodiment the channels 182 are in the form of hexagonal cross section tubes 184 to enable close packing. The channels 182 / tubes 184 are formed by corrugated stacked plates 186 arranged with respective corrugations aligned and offset thereby forming an array of closely spaced parallel tubes or channels. The angle of the channels 182, cross sectional area and height of the stack are predetermined to provide a reduction of flow velocity of water passing through the lamellar stack 22 and provide a large surface area for solids suspended in the water to collide and coalesce which aids them to fall out of suspension and sink to the bottom of the chamber for later removal. In this embodiment, as shown in Fig.15 the channels 182 have a dimension D measured across opposing flats of around 30mm and a wall thickness W of approximately 1mm. The plates 186 may be formed of a metal, such as a steel, and preferably a stainless steel, plastics material such as PVC, composite materials or even ceramics.

[0062] The efficiency of the lamella clarifier for removing suspended particles diminishes as the contact time of the water with the inclined plates reduces. Contact time is determined by the dimensions of the stack and velocity of the water passing there though. Water velocity is a function of flow rate and inlet surface area of the lamella clarifier stack. Accordingly, the maximum treatment flow rate (TFR) for a given device is determined by the capacity of the lamella clarifier stack. Advantageously, the total surface area of the lamella clarifier stack correlates with the device design including the dimensions and relative level of the main inlet and outlet, weir shape and size configuration of the bypass and treatment outlets so that the velocity of the water passing through the lamella clarifier 19is controlled within a predetermined operating range allowing for a minimum contact time with the inclined plates, regardless of the flow rate of water into the device within operational parameters. In short, the water flow rate through the treatment circuit and treatment chamber is controlled by the design of the device to maintain a minimum optimal contact time for the lamella clarifier.

[0063] In order to increase the maximum treatment rates of a water treatment system, the device may be used with other like devices connected in parallel and / or scaled up in capacity. In terms of scalability (of maximum treatment rates either up or down) of a single device, the total surface area of the inclined plates correlates with the dimensions of the treatment chamber toensure that the velocity of the water within the chamber corresponds to the minimum contact time with the inclined plates, regardless of the size of the device and / or chamber. In short, the water velocity through the chamber and the contact time per unit area of inclined plates is within a predetermined range and in particular below a maximum velocity regardless of the scale of the device, but dependent on design of the lamellar stack.

[0064] Broad ranging Computational Fluid Dynamics (CFD) modelling may be undertaken to optimise the treatment flow rates for each of the device models. By way of example, in one embodiment CFD modelling determined the optimum sump velocity and flow rate per unit area through the lamella stack to achieve 99% Total Suspended Solids (TSS) capture at a particle size of 200 um and above. To achieve this consistent outcome, the device is designed to have a sump velocity of around 0. Im / s, and a flow rate per unit area through the lamella stack of 2.5 L / s / m2(± 0.1 L / s / m2). The flow rate per unit area is dependent in part upon the design of the lamellar stack and includes internal surface area of the channels.

[0065] In this embodiment as seen in Fig. 15, the lamellar stack is formed from a plastic material and is supported by a frame 188 formed from a stainless steel, although other materials may be used for the frame 188. The frame 188 encapsulates the lamellar structure so it may be anchored to the wall of the main chamber or to the insert assembly, such as by treaded connectors without damaging the lamellar structure. In other embodiments, depending on the rigidity of the stack, a frame is not used and the lamellar stack is secured directly to the wall of the main chamber or to the insert assembly.

[0066] It will be appreciated that other lamella clarifier designs and methods of manufacture may be used.

[0067] A space 190 above the lamella clarifier 19 and below the inlet chamber 12 and weir provides an outlet passageway for water, having passed through the lamella clarifier 19to flow to the main exit 14 from the treatment chamber. The space 190 is defined by a nominal vertical distance between the lowermost levels of the main inlet 10 and the main outlet 14 which also provides the head to generate hydraulic drainage through the device 1 so that water flows through the treatment circuit, provided by the treatment outlet, treatment chamber filter, and then to the main outlet.

[0068] An inlet flow guides comprising one or more inlet flow vanes 192 are located in the inlet chamber downstream of the main inlet 10. A further flow guide comprising one or more outlet flow vanes 194 are between the end of the outlet ramp and the main outlet 14 directing the water flowing over the weir and bypassing the treatment circuit toward the main outlet 14 so as to prevent backflow into the treatment chamber. The flow guides further reduces turbulence and encourages laminar flow of bypass water into the main outlet.

[0069] As noted, the main body 100 includes an open top 130 which may be closed by a removable cover or lid 132. The open top 130 allows for access to the main chamber and internals for maintenance and cleaning particularly of debris and sediments accumulated in bottom of the main chamber and floatables in the floatable storage zone. In this embodiment, ports 196 in the lid are provided each having a respective port cap (not shown) for accessing and inspecting internal areas of the device without requiring removal of the entire lid 132.

[0070] In this embodiment the device includes a flushing system best seen in Figure 13 consisting of a series of conduits 202 and nozzles 205 & 207, to assist in cleaning and maintenance of the device. The flushing system is accessed via the opening 130 and is provided with a hose connection 204 for attachment of a pressurized supply of water for flushing the device. Once pressurized, the nozzles direct jets of water to dislodge debris within the device. In particular some nozzles 205 are disposed to direct jets 206 to reverse flush the lamella clarifier 19. Other nozzles 207 are disposed to direct jets 208 to spray the internal sides and bottom of the chamber 100 to push debris toward the floatables storage zone side of the chamber where it may be removed through the opening 130 unimpeded by the insert assembly and baffle wall 108.

[0071] With reference to Fig. 13, a first array of nozzles is disposed at or near the floor of the main chamber in the treatment chamber, underneath the inlet assembly and lamellar stack. This line is responsible for pushing the collected debris from the difficult to reach side of the chamber to the more accessible side for collection via vacuum truck.

[0072] A second array of nozzles is located on top of the lamella tube stack and is used to back flush the system and clear out any built-up sediments or debris in the lamella assembly.

[0073] The flushing system is installed permanently inside the unit with the end connection points terminated at surface level. When cleaning of the unit is performed a maintenance workerwill connect to the high-pressure water lines at the surface and simultaneously back flush the lamella stack whilst moving the debris from one side of the unit to the other for ease of removal.

[0009] In use, the main inlet is connected to a stormwater pipe by means of inlet connector. Water to be treated from the stormwater pipe enters the device via the main inlet where in flows into the inlet chamber. The untreated water may carry pollutants including soluble and insoluble foreign matter including solid matter and liquids. Insoluble solid matter may include solid objects such as particulate sands & soils, larger debris, rubbish, organic matter including grass cuttings, leaves and sticks, and inorganics and manufactured waste including plastic objects. Other insoluble liquids may comprise, particularly lighter density liquids such as hydrocarbon liquids, fats, oils and greases. The insoluble matter may range from dense, negatively buoyant matter and liquids to light, positively buoyant floatable material and liquids.

[0074] Since the treatment outlet is set low in the inlet chamber, at or below the inlet chamber floor and at least partially below the bypass outlet, water, and any solid matter carried by the water entering the inlet chamber is preferentially diverted through the treatment outlet into the treatment circuit. Where the flow rate of water into the inlet chamber is below the maximum treatment flow rate, the water is discharged from the inlet chamber through the treatment inlet and treatment circuit at the same rate it enters the inlet chamber. That is to say all water entering the device will pass through the treatment circuit for treatment since maximum treatment flow rate exceeds the flow rate into the device such that water will not accumulate in the inlet chamber and the level of water in the inlet chamber remains relatively low.

[0075] The untreated water and accompanying pollutants diverted into the treatment circuit pass from the inlet chamber into the floatable storage zone as seen in Figs. 5 and 11 between the main chamber wall and baffle wall. Positively buoyant pollutants, which can take the form of litter, debris, lighter density liquids, or any other pollutant that can readily float on water, are captured in the floatables storage zone, and retained behind the baffle wall since they will remain on the surface of the water in the main chamber and unable to sink to pass below the baffle wall. This reduces the likelihood that the floatable materials pass into the treatment chamber where they may foul the lamella clarifier. However, water to be treated, free of floatables may flow under the baffle wall and into the treatment chamber whilst negatively buoyant matter carried by the water sinks to the bottom of the main chamber into the sump sediments storage zone where it may accumulate.

[0076] The water in the treatment chamber passes upward to exit to the main outlet via the outlet passageway under hydraulic drainage driven by the relative levels of the main inlet and outlet. It will be noted that the cross section of the treatment chamber is comparatively large relative to the cross section of the main inlet, thus the upward flow velocity of water in the treatment chamber is relatively low. This encourages particulates and less negatively buoyant sediments and debris to settle into the lower section of the chamber rather than becoming entrained in the flow of water and swept upward.

[0077] Some matter, particularly particulate matter or matter with generally neutral buoyancy remaining in the water may still contain debris and sediments that could not settle in the debris and sediments storage zone due to the velocity of the volumetric flow rate. The water along with these finer particulars carries with it passes upward through the lamella clarifier (filter), which due to surface contact with the tubes and reduce flow velocities at the boundary layer, encourages the coalescing of finer debris and sediments into larger particles that have an increased tendency to settle into the debris and sediments storage zone due to their negative buoyancy.

[0078] Advantageously, the flow velocity and flow profile of water in the treatment chamber is controlled such that once the debris and sediments have settled, they are less likely to be resuspended and flushed out of the chamber. This may be assisted by increasing the depth of the main chamber or providing further baffles and vanes at or adjacent the floor of the main chamber in the sump area so as to provide a generally decreasing flow velocity gradient with increasing water depth and in some cases still (or near still) water zones.

[0079] The treated water, having passed through the lamella clarifier enters outlet passageway that is located above the clarifier and beneath the broad crested weir where it flows to the main outlet and is discharged to the stormwater piping.

[0080] At high flow rates, where the volumetric flow rate of the water entering the inlet chamber via the main inlet exceeds the maximum treatment flow rate, water accumulates in the inlet chamber such that the water level will rise until it approaches and exceeds the bypass height defined by the crest of the broad crested weir. The excess untreated water passes directly over the top of the broad crested weir and flows down the outlet ramp and is channeled into themain outlet by the flow guides thereby bypassing the treatment circuit. However, even under these conditions some water is diverted through the treatment circuit for treatment.

[0081] Some water may flow over the broad crested weir before the water level in the inlet chamber reaches the level of the crest of the weir due to flow velocity of the water. However this is somewhat mitigated by the inlet chamber cross section area being greater than the area of the inlet so that the water slows in velocity as it enters the inlet chamber.

[0082] When the device needs to be maintained, the main chamber may be accessed by way of the opening at the top of the main body. The cover may be removed and the contents of the debris and sediments storage zone and floatables storage zone may be removed. This may include pumping out water held in the main chamber.

[0083] Once the contents of the debris and sediments storage zone and floatables storage zone have been removed, the inclined plates and the debris and sediments storage zone may be flushed clean by way of the flushing system and the residual flushed pollutants removed for completeness of the clean.

[0084] It will be appreciated that the invention involves the elimination of moving parts which introduce potential points of failure. The invention employs alternative static mechanisms to achieve debris retention. This design innovation advantageously enhances reliability, simplifies maintenance, and may lead to long-term cost savings.

[0085] The separating treatment chamber consists of three zones. The inlet zone, where the energy of the incoming flow is dissipated and treatment flows diverted to the treatment chamber, a larger middle settling zone where quiescent conditions allow solids / particulate matter to settle for later removal, and a post treatment exit phase.

[0086] At high sub-critical inflow, the overall water depth inside the device increases and the excess flow passes evenly over the weir and into the retum / bypass channels and then to the outlet.

[0087] If total blocking of the lamella tube elements was to occur, the water level in the device will rise and spill over the bypass weir and into the retum / bypass channels for conveyancedirectly to the main outlet. This effectively creates a failsafe internal bypass mechanism that ensures the device will not cause impedance in the pipeline flow under any circumstances.

[0088] The design presented in this description is based on a stormwater treatment application and is scalable from treatment flow rates as low as 20 litres per second, up to treatment flow rates in the order of hundreds of litres per second.

Claims

CLAIMS1. A water treatment device comprising: a main inlet for receiving a flow of water into the water treatment device; a main outlet for the discharge of water from the water treatment device; a treatment circuit for receiving water to be treated and returning treated water to the main outlet for discharge, said treatment circuit comprising a lamella clarifier and a sump for the collection of solid particles; a bypass circuit allowing water entering the device from the main inlet to bypass the treatment circuit and to be diverted to the main outlet for discharge; a water diverter downstream of the main inlet configured to preferentially divert water from the main inlet through the treatment circuit and to divert at least a portion of the flow of water into the device through the bypass circuit when an operational parameter determined by the flow of water into the treatment device exceeds a predetermined level.

2. The water treatment device of claim 1, wherein the predetermined parameter is associated with a flow rate of water into the device including a flow rate of water through the treatment circuit such as a maximum treatment flow rate (TFR) of the treatment circuit.

3. The water treatment device of claim 1 or 2, wherein the diverter comprises a treatment inlet for directing water into the treatment circuit from the main inlet and a bypass inlet for directing water into the bypass circuit from the main inlet.

4. The water treatment device of claim 3, wherein at least a portion of the treatment inlet is disposed below a lower extremity of the bypass inlet.

5. The water treatment device of claim 3 or 4, wherein the treatment inlet and the bypass inlet are disposed within an inlet chamber for receiving water from the main inlet and wherein the predetermined parameter is a bypass height of a water level in the inlet chamber.

6. The water treatment device of claim 5, wherein the bypass height is determined by a lower extremity of the bypass inlet.

7. The water treatment device of claim 6, wherein the bypass inlet includes a weir adapted to prevent water passing through the bypass inlet when the water level in the inlet chamber is below said bypass height.

8. The water treatment device of claim 7, wherein the weir is a includes a weir crest set at the lower extremity of the bypass inlet.

9. The water treatment device of claim 8, wherein the weir is a broad crested weir having a gradual upward sloping entry extending from a floor of the inlet chamber to a smooth waveform crest and an outlet ramp sloping gradually downwardly toward the main exit.

10. The water treatment device of any one of the preceding claims, wherein the lamella clarifier is disposed in a treatment chamber of the treatment circuit.

11. The water treatment device of any one of the preceding claims, wherein the lamella clarifier includes a lamella coalescing stack.

12. The water treatment device of claim 11, wherein the lamella clarifier comprises an inclined lamella tube settler and / or inclined lamella plate settler.

13. The water treatment device of claim 11, wherein the lamella coalescing stack comprises an array of closely spaced parallel channels angled relative to the flow direction of water in the treatment chamber.

14. The water treatment device of any one of the preceding claims wherein the treatment circuit includes a floatables storage zone for the collection and retention of buoyant matter.

15. IThe water treatment device of claim 14 including a baffle wall dividing the treatment chamber from the floatables storage zone.

16. The device of any one of the preceding claims, further including a flushing system for flushing the device of debris.

17. The water treatment device of claim 18, wherein the flushing system comprises series of conduits and nozzles directing jets of water to flush portions of the treatment circuit for cleaning.

18. A water treatment device comprising: a main inlet for receiving a flow of water into the water treatment device; a main outlet for the discharge of water from the water treatment device; a treatment circuit for receiving water to be treated and returning treated water to the main outlet for discharge, said treatment circuit comprising: a lamella clarifier; and a sump for the collection of solid particles; a bypass circuit allowing water entering the device from the main inlet to bypass the treatment circuit and to be diverted to the main outlet for discharge; a water diverter downstream of the main inlet comprising an inlet chamber or area having a treatment inlet for directing water into the treatment circuit from the main inlet and a bypass inlet for directing water into the bypass circuit from the main inlet; and wherein at least a portion of the treatment inlet is disposed below a lower extremity of the bypass inlet.

19. The water treatment device of claim 17, wherein the inlet chamber includes a weir adapted to prevent water passing through the bypass inlet when a water level in the inlet chamber is below a predetermined level and allow at least a proportion of the water in the inlet chamber into the bypass circuit via the bypass inlet when the water level in the inlet chamber is above, a predetermined level.

20. The water treatment device of claim 18, wherein predetermined level is set by the lower extremity of the bypass inlet.

Images