TECHNICAL FIELD

[0001] The present invention relates to a clarifier for clarifying a liquid, to liquid purification systems and to methods of clarifying a liquid.

BACKGROUND ART

[0002] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

[0003] Traditional fluid clarifiers include a large diameter circular settling tank, which is substantially wider than it is high. The base of the settling tank is typically inclined from a central sludge pipe located in the base towards the side walls of the settling tank. A slow-moving rake rotates to rake the base and assist agglomerated particles to exit the clarifier through the central sludge pipe. Clean water exits the clarifier by travelling over the upper side walls of the settling tank. Such traditional fluid clarifiers have disadvantages in that they are very large, they are not portable and they are frequently very expensive.

[0004] A further type of fluid clarifier involves the use of lamellae, or a series of inclined plates, in a settling tank (a lamella clarifier). The lamellae provide an increased effective settling area for agglomerated particles, which enables the size of the clarifier to be reduced. However, such a clarifier may still be relatively large, non-portable and expensive.

[0005] Yet another type of fluid clarifier involves the use of a series of compartments, each having a distinct function, to clarify a liquid. Such a type of fluid clarifier is produced by Veolia Water Technologies under the Actiflo™ brand, and Suez under the Densadeg™ brand. In such a clarifier a chemical coagulant may be added to the liquid to be clarified prior to entry into the clarifier. The liquid then enters a first compartment in which the liquid is mixed at high speed to promote coagulation. The coagulated liquid then passes to a second compartment in which the liquid is mixed at lower speed to promote flocculation (a ballast such as sand may be added to aid flocculation). The flocculated fluid then passes to a third compartment having lamellae in an upper portion, and a slow moving rake in a lower portion, in which the floe settles. Clarified liquid exits the third compartment by passing through the lamellae, and settled floe may be treated (for example with a hydrocyclone). However, whilst such clarifiers may be portable, they are still relatively large, and they also include many moving parts which would require maintenance.

SUMMARY OF INVENTION

[0006] In one aspect, the present invention is directed to a clarifier which is portable, which has a smaller footprint than many existing clarifiers, or which is less expensive to manufacture and/or maintain than many existing clarifiers. In another aspect, the present invention is directed to a clarifier which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

[0007] With the foregoing in view, the present invention in one form, resides broadly in a clarifier for clarifying a liquid.

[0008] In a first aspect, the present invention relates to a clarifier for clarifying a liquid, the clarifier including:

- An agglomeration vessel for agglomeration of floe, wherein the agglomeration vessel includes a fluid inlet for tangentially introducing a liquid to be clarified into the agglomeration vessel, and a bottom wall including a floe outlet for removal of floe sediment; and

- A sedimentation vessel for sedimentation of floe, wherein the sedimentation vessel is in fluid communication with the agglomeration vessel, and wherein the sedimentation vessel includes a fluid outlet for clarified liquid.

[0009] Advantageously, tangential introduction of a liquid to be clarified into the agglomeration vessel may result in a centrifugal motion of the liquid to be clarified in the agglomeration vessel. In such a centrifugal motion the liquid may move more quickly and with greater turbulence along the periphery of the agglomeration vessel than in the centre. Such centrifugal motion may assist in agglomerating floe.

[0010] In one embodiment, the agglomeration vessel includes an upper wall opposite to the bottom wall defining an aperture, and at least one side wall extending between the bottom wall and the upper wall; wherein the upper wall is declined from the at least one side wall towards the aperture. In a further embodiment, the sedimentation vessel includes a weir positioned above an inlet to the fluid outlet for removal of matter that floats on or is less dense than the liquid to be clarified.

[0011] In a second aspect, the present invention relates to a clarifier for clarifying a liquid, the clarifier including:

- An agglomeration vessel for agglomeration of floe, wherein the agglomeration vessel includes a fluid inlet for introducing a liquid to be clarified into the agglomeration vessel; and wherein the agglomeration vessel includes a bottom wall including a floe outlet for removal of floe sediment, an upper wall opposite to the bottom wall defining an aperture, and at least one side wall extending between the bottom wall and the upper wall; wherein the upper wall is declined from the at least one side wall towards the aperture; and

- A sedimentation vessel for sedimentation of floe, wherein the sedimentation vessel is in fluid communication with the agglomeration vessel via the aperture in the upper wall of the agglomeration vessel, and wherein the sedimentation vessel includes a fluid outlet for clarified liquid.

[0012] Advantageously, an upper wall that is declined from the at least one side wall towards the aperture may assist in retaining fine particles of floe in the agglomeration vessel.

[0013] In one embodiment, the agglomeration vessel fluid inlet is for (or is configured or adapted to) tangentially introducing a liquid to be clarified into the agglomeration vessel. In a further embodiment, the sedimentation vessel includes a weir positioned above an inlet to the fluid outlet for removal of matter that floats on or is less dense than the liquid to be clarified.

[0014] In a third aspect, the present invention relates to a clarifier for clarifying a liquid, the clarifier including:

- An agglomeration vessel for agglomeration of floe, wherein the agglomeration vessel includes a fluid inlet for introducing a liquid to be clarified into the agglomeration vessel, and a bottom wall including a floe outlet for removal of floe sediment; and

- A sedimentation vessel for sedimentation of floe, wherein the sedimentation vessel is in fluid communication with the agglomeration vessel; wherein the sedimentation vessel includes a fluid outlet for clarified liquid; and wherein the sedimentation vessel includes a weir positioned above an inlet to the fluid outlet for removal of matter that floats on or is less dense than the liquid to be clarified.

[0015] Advantageously, a weir positioned above the fluid outlet may assist in clarifying liquids that include matter that floats on the liquid or less dense liquids. For example, if a water solution including hydrocarbons is being clarified, a weir may permit residual hydrocarbons which travel into the sedimentation vessel to be removed from the liquid via the weir, rather than the hydrocarbons travelling into the fluid outlet.

[0016] In one embodiment, the agglomeration vessel fluid inlet is for tangentially introducing a liquid to be clarified into the agglomeration vessel. In another embodiment, the agglomeration vessel includes an upper wall opposite to the bottom wall defining an aperture, and at least one side wall extending between the bottom wall and the upper wall; wherein the upper wall is declined from the at least one side wall towards the aperture.

[0017] In a fourth aspect, the present invention relates to a clarifier for clarifying a liquid, the clarifier including:

- An agglomeration vessel for agglomeration of floe, wherein the agglomeration vessel includes a fluid inlet for introducing a liquid to be clarified into the agglomeration vessel, and a bottom wall including a floe outlet for removal of floe sediment; and

- A sedimentation vessel for sedimentation of floe, wherein the sedimentation vessel is in fluid communication with the agglomeration vessel, and wherein the sedimentation vessel includes a fluid outlet for clarified liquid.

[0018] In one embodiment of the fourth aspect, there is provided a clarifier for clarifying a liquid, the clarifier including:

- An agglomeration vessel for agglomeration of floe, wherein the agglomeration vessel includes a fluid inlet for introducing a liquid to be clarified into the agglomeration vessel, and a bottom wall including a floe outlet for removal of floe sediment; and

- A sedimentation vessel for sedimentation of floe, wherein the sedimentation vessel is in fluid communication with the agglomeration vessel, and wherein the sedimentation vessel includes a fluid outlet for clarified liquid; wherein the fluid outlet includes a floe collection chamber for collection of floe.

[0019] Features of the first to fourth aspects of the present invention follow. [0020] As used herein, references to vertical, horizontal or the like, refer to the vertical or horizontal orientation (for example) when the clarifier is in an operating configuration.

[0021] In one embodiment, the agglomeration vessel may be configured to agglomerate floe in the liquid to be clarified via centrifugal force. The agglomeration vessel may be configured (or be adapted) to centrifugally rotate the liquid to be clarified within the agglomeration vessel. This may be achieved by the tangential introduction of a liquid to be clarified into the agglomeration vessel. The agglomeration vessel may include no mechanical stirrers. The agglomeration vessel may include no moving mechanical parts.

[0022] The agglomeration vessel may include an upper wall opposite to the bottom wall, and at least one side wall extending between the bottom wall and the upper wall.

[0023] The agglomeration vessel at least one side wall may be substantially circular or ovoid, especially substantially circular. The at least one side wall may be of any suitable diameter. In one embodiment, the at least one side wall may be from 1 to 5 metres in diameter, especially from 1.5 to 4 metres in diameter, more especially from 2 to 3 metres in diameter. The at least one side wall may be about 2.4 metres in diameter. The at least one side wall may extend substantially vertically. The at least one side wall may be from 0.5 to 5 metres in width, especially from 1 to 2 metres in width, most especially about 1.5 metres in width (or height).

[0024] The bottom wall of the agglomeration vessel may be declined from the at least one side wall towards the floe outlet for removal of floe sediment. The bottom wall of the agglomeration vessel may be declined from the at least one side wall to the floe outlet for removal of floe sediment. The bottom wall may be declined at any suitable angle. In one embodiment, the bottom wall is angled at from 30 to 80° from the horizontal, especially at from 40 to 75° or from 50 to 70° from the horizontal. In another embodiment, the bottom wall is angled at about 60° from the horizontal. In one embodiment, the bottom wall is angled at from 120 to 170° from the at least one side wall, especially at from 130 to 165° or from 140 to 160° from the at least one side wall. In another embodiment, the bottom wall is angled at about 150° from the at least one side wall. The bottom wall of the agglomeration vessel may be configured (or adapted) to direct agglomerated floe to the floe outlet.

[0025] The bottom wall may be of any suitable shape. In one embodiment, the bottom wall is substantially inversely conical.

[0026] The floe outlet may be in any suitable position on the bottom wall. In one embodiment, the floe outlet is positioned at substantially the centre of the bottom wall. In one embodiment, the floe outiet may be shaped like an inverted cone, with the floe outlet at the base. This configuration may assist in directing agglomerated floe to the floe outlet.

[0027] The floe outlet may be of any suitable size. In one embodiment, the floe outlet is from 0.02 to 0.1 metres wide, especially from 0.04 to 0.08 metres wide, more especially from 0.05 to 0.07 metres wide, most especially about 0.06 metres wide. The floe outlet may be in fluid connection, for example via a pipe extending from the floe outlet, with a rotary valve (or unloader). The rotary valve may rotate as agglomerated floe settles in the valve, resulting in the agglomerated floe travelling away from the clarifier. The rotary valve (or unloader) may prevent air from travelling into the clarifier via the floe outlet. The floe outlet may be in fluid communication with, for example, a dewatering device such as a screw press. The rotary valve may be under negative pressure. For example, a pump may be positioned between the screw press and the rotary valve. In this case, the rotary valve may prevent the pump from disturbing the liquid to be clarified in the clarifier.

[0028] The agglomeration vessel may include an upper wall opposite to the bottom wall. The upper wall may define an aperture. The aperture may be a plurality of apertures, however the aperture is especially one aperture. The aperture(s) may be in any suitable position. In one embodiment, the aperture is substantially centrally located. In one embodiment, the aperture is a central aperture. The upper wall may be declined from the at least one side wall towards the aperture on at least one side of the aperture, more especially on all sides of the aperture. The upper wall may include a substantially conical portion. The aperture may be located at the centre of the substantially conical portion. The substantially conical portion may be an inversely positioned substantially conical portion. The upper wall may also include a cylindrical portion. The cylindrical portion may be in register with (or extend from, be connected to, or integrally formed with) the substantially conical portion. The aperture may be at the centre of the cylindrical portion. The aperture may be of adjustable size. In one embodiment, the declined upper wall of the agglomeration vessel defines a substantially conical portion of the agglomeration vessel upper wall, the upper wall of the agglomeration vessel further includes a substantially cylindrical portion extending from the substantially conical portion, and the substantially conical portion and the substantially cylindrical portion define the aperture in the upper wall of the agglomeration vessel.

[0029] The upper wall may be declined at any suitable angle. In one embodiment, at least a portion (especially the substantially conical portion) of the upper wall is angled at from 10 to 60° from the vertical or from the at least one side wall, especially at from 15 to 50° or from 20 to 40° from the vertical or from the at least one side wall. In another embodiment, at least a portion (especially the substantially conical portion) of the upper wall is angled at about 30° from the vertical or from the at least one side wall.

[0030] The cylindrical portion of the upper wall may be of any suitable length. In one embodiment, the cylindrical portion may be from 0.1 to 1 metre in length, especially from 0.3 to 0.8 metres in length, more especially about 0.45 metres in length. The cylindrical portion may extend into the agglomeration vessel. The cylindrical portion may also extend away from the agglomeration vessel. The cylindrical portion may extend substantially parallel to the at least one side wall. The cylindrical portion may extend substantially vertically.

[0031] The upper wall may also include an inclined portion. The inclined portion may extend from the cylindrical portion. The inclined portion may extend from the cylindrical portion towards the at least one side wall. The inclined portion may extend at any suitable angle. The inclined portion may extend at from 95 to 175° relative to the cylindrical portion (or the vertical), especially at from 105 to 165°, or from 115 to 155°, or from 125 to 145° or about 135° relative to the cylindrical portion (or the vertical). The inclined portion may be configured to direct liquid in the agglomeration vessel towards the at least one side wall. The inclined portion may advantageously assist in the agglomeration of floe. The inclined portion may also improve the rigidity of the cylindrical portion.

[0032] The upper wall may define an aperture of any suitable size. The aperture may be from 0.5 metres to 3 metres in diameter, especially from 0.7 metres to 2 metres in diameter, more especially from 0.9 metres to 1.5 metres in diameter, most especially about 1.2 metres in diameter.

[0033] The at least one fluid inlet may extend into the agglomeration vessel through the at least one side wall or through the bottom wall, especially through the at least one side wall. A substantially circular side wall, through which a fluid inlet extends to tangentially introduce a liquid to be clarified in the agglomeration vessel, may advantageously assist in providing centrifugal rotation of the liquid to be clarified in the agglomeration vessel.

[0034] The agglomeration vessel may include at least one fluid inlet for introducing a liquid to be clarified into the agglomeration vessel. The at least one fluid inlet may be a plurality of fluid inlets. In one embodiment the at least one fluid inlet is 1, 2, 3, 4, 5, 6, 7 or 8 fluid inlets, especially 1, 2, 3 or 4 fluid inlets.

[0035] The at least one fluid inlet may be for tangentially introducing a liquid to be clarified into the agglomeration vessel. The at least one fluid inlet may be of any suitable structure. For example, the at least one fluid inlet may include a pipe extending into the agglomeration vessel. The terminal end of the fluid inlet (i.e. where the liquid to be clarified exits the inlet into the agglomeration vessel) may be positioned or angled to direct the liquid to be clarified away from the centre of the agglomeration vessel. The terminal end of the fluid inlet may be positioned or angled to direct the liquid substantially along or parallel to the at least one side wall. The terminal end of the fluid inlet may be angled to direct the liquid at from 0 to 45° relative to the at least one side wall, especially at from 0 to 25° or from 0 to 10° or from 0 to 5° relative to the at least one side wall. The terminal end of the fluid inlet may be angled to direct the liquid substantially perpendicularly to the centre of the agglomeration vessel.

[0036] The tangential introduction of a liquid to be clarified into the agglomeration vessel may assist in creating a cyclone effect within the agglomeration vessel, and collisions between floe and the walls of the agglomeration vessel. The liquid moving closest to the at least one side wall of the agglomeration vessel may move more quickly than liquid moving towards the centre of the agglomeration vessel. If the aperture in the upper wall of the agglomeration vessel is positioned in the centre of the upper wall, this may mean that the liquid departing the agglomeration vessel through the aperture is the most slowly moving liquid in the agglomeration vessel, potentially minimising turbulence within the sedimentation vessel.

[0037] The centrifugal rotation of the liquid in the agglomeration vessel, together with a declined bottom wall in the agglomeration vessel may assist in the agglomeration of floe, as the centrifugal force may drive the floe up the declined bottom wall, whilst gravity, surface friction, turbulence and fluid direction may assist the floe to travel down the declined wall. Consequently, floe which travels all the way down the declined bottom wall may have agglomerated to reach at least a defined size.

[0038] The centrifugal rotation of the liquid in the agglomeration vessel, together with a declined upper wall in the agglomeration vessel may also assist in the agglomeration of floe. It would be expected that finer floe particles would rise higher in the agglomeration vessel than larger floe particles. The declined upper wall ameliorates the possibility of such particles from escaping the agglomeration vessel. The declined upper wall would also act to drive the liquid to be clarified downwards, towards the bottom wall. Similarly, a substantially conical portion in the upper wall which extends into the agglomeration vessel may also ameliorate the possibility of finer floe particles from escaping the agglomeration vessel.

[0039] The at least one fluid inlet may be in fluid communication with a pump. Liquid to be clarified may be pumped into the agglomeration vessel. Pumping the liquid to be clarified into the agglomeration vessel may assist in generating centrifugal rotation within the vessel. The pump may be a variable speed pump. Increasing the speed of the pump may increase the speed of the liquid exiting the fluid inlet, which may lead to increased collisions between floe particles (and agglomeration of floe particles) and decreased settling of floe. Similarly, decreasing the speed of the pump may decrease the speed of the liquid exiting the fluid inlet, which may lead to decreased collisions between floe particles (and agglomeration of floe particles) and increased settling of floe. Altering the speed of the pump may also allow an operator to control the speed at which clarified liquid departs the fluid outlet for clarified liquid. Consequently, if the clarified liquid contains too much floe a user could simply slow down the speed of the pump which would provide more time for floe to settle within the clarifier.

[0040] The clarifier may be configured to apply non-uniform centrifugal forces on the liquid to be clarified. If the centrifugal forces are uniform, then floe entrained within the liquid will move more uniformly, and agglomeration within the liquid to be clarified would be slowed. On the other hand, if the centrifugal forces are not uniform, then the floe entrained within the liquid will not move uniformly, and consequently agglomeration within the liquid to be clarified would be increased. Non-uniform centrifugal forces may be applied by, for example, oscillating the speed of the pump introducing the liquid to be clarified, or using an agglomeration vessel with a non-uniformly curved side wall, or by including a fluid inlet which is oriented in the opposite direction to other fluid inlets in the agglomeration vessel.

[0041] In one embodiment, the pump is configured to introduce the liquid to be clarified at an oscillating velocity. Such an oscillating velocity may effectively result in the introduction of the liquid to be clarified in the agglomeration vessel in a pulsed manner.

[0042] In another embodiment, the agglomeration vessel may include at least one flow disturber. The at least one flow disturber may extend from the at least one side wall, the upper wall or the bottom wall of the agglomeration chamber. The at least one flow disturber may be a barrier. The barrier may be rotatable. In one embodiment, the barrier may be substantially planar or substantially curved. The barrier may be substantially square or rectangular in shape. The barrier may have a smaller thickness than length. Advantageously, rotating the barrier so that the smallest face is substantially directed towards the flow of liquid within the agglomeration vessel may minimise disturbances in the flow. On the other hand, rotating the barrier so that the largest face is substantially directed towards the flow of liquid within the agglomeration vessel may maximise disturbances in the flow. [0043] The at least one flow disturber may also include a fluid inlet which is oriented in the opposite direction to other fluid inlets in the agglomeration vessel. Bursts of liquid may be introduced via the oppositely oriented fluid inlet to disturb the flow.

[0044] The at least one flow disturber may be a surface coating, especially a roughened surface coating, on a wall of the agglomeration chamber. For example, at least one side wall may have a roughened surface. It is believed that a roughened surface may assist in the agglomeration of floe.

[0045] The sedimentation vessel may be positioned above the agglomeration vessel. The sedimentation vessel may be positioned directly above the agglomeration vessel. The sedimentation vessel may be in fluid communication with the agglomeration vessel via the aperture in the upper wall of the agglomeration vessel. Typically, as liquid flows through the sedimentation vessel it becomes less turbulent, which encourages floe to settle.

[0046] The sedimentation vessel may include one or more of a bottom wall, an upper wall opposite the bottom wall and at least one side wall extending between the bottom wall and the upper wall.

[0047] The bottom wall of the sedimentation vessel may define an aperture. The aperture may be a plurality of apertures, however the aperture is especially one aperture. The aperture(s) may be in any suitable position. In one embodiment, the aperture is substantially centrally located in the bottom wall. In one embodiment, the aperture is a central aperture. The bottom wall may be declined from the at least one side wall towards the aperture on at least one side of the aperture, more especially on all sides of the aperture. The bottom wall may include a substantially conical portion. The aperture may be located at the centre of the substantially conical portion. The substantially conical portion may be an inversely positioned substantially conical portion. The bottom wall may also include a cylindrical portion. The cylindrical portion may be in register with (or connected to, or integrally formed with) the substantially conical portion. The aperture may be at the centre of the cylindrical portion. The aperture may be of adjustable size.

[0048] The bottom wall of the sedimentation vessel may be declined at any suitable angle. In one embodiment, at least a portion (especially the substantially conical portion) of the bottom wall is angled at from 30 to 80° from the horizontal, especially at from 40 to 75° or from 50 to 70° from the horizontal. In another embodiment, at least a portion (especially the substantially conical portion) of the bottom wall is angled at about 60° from the horizontal. In one embodiment, the bottom wall is angled at from 120 to 170° from the at least one side wall, especially at from 130 to 165° or from 140 to 160° from the at least one side wall. In another embodiment, the bottom wall is angled at about 150° from the at least one side wall. The bottom wall of the sedimentation vessel may be configured (or adapted) to direct floe sediment to the aperture.

[0049] The cylindrical portion of the bottom wall of the sedimentation vessel may be of any suitable length. In one embodiment, the cylindrical portion may be from 0.1 to 1 metre in length, especially from 0.3 to 0.8 metres in length, more especially about 0.45 metres in length. The cylindrical portion may extend away from the sedimentation vessel.

[0050] The bottom wall of the sedimentation vessel may define an aperture of any suitable size. The aperture may be from 0.5 metres to 3 metres in diameter, especially from 0.7 metres to 2 metres in diameter, more especially from 0.9 metres to 1.5 metres in diameter, most especially about 1.2 metres in diameter.

[0051] The bottom wall of the sedimentation vessel may be in register with, or extend from, the substantially conical portion of the upper wall of the agglomeration vessel. The bottom wall of the sedimentation vessel may be integrally formed with the upper wall of the agglomeration vessel. The bottom wall of the sedimentation vessel may be the upper wall of the agglomeration vessel. Advantageously, this arrangement provides a more compact clarifier.

[0052] The clarifier may be configured so that substantially all floe sediment from the sedimentation vessel enters the agglomeration vessel. In one embodiment, the clarifier is configured so that substantially all floe sediment from the sedimentation vessel exits the clarifier through the floe outlet in the bottom wall of the agglomeration vessel. In one embodiment, substantially all floe sediment from the sedimentation vessel enters the agglomeration vessel due to gravity. For example, floe sediment from the sedimentation vessel may descend down the declined bottom wall of the sedimentation vessel, through the aperture and into the agglomeration vessel.

[0053] The sedimentation vessel at least one side wall may be substantially circular or ovoid, especially substantially circular. The at least one side wall may be of any suitable diameter. In one embodiment, the at least one side wall may be from 1 to 5 metres in diameter, especially from 1.5 to 4 metres in diameter, more especially from 2 to 3 metres in diameter. The at least one side wall may be about 2.4 metres in diameter. The at least one side wall may extend substantially vertically. The at least one side wall may be from 0.5 to 5 metres in width, especially from 1 to 4 metres in width, most especially about 1.9 metres in width (or height). The at least one side wall of the sedimentation vessel may extend from (or be integral with) the at least one side wall of the agglomeration vessel.

[0054] The sedimentation vessel upper wall may be substantially planar.

[0055] The sedimentation vessel includes a fluid outlet for clarified liquid. The fluid outlet may be in an upper portion of the sedimentation vessel. The fluid outlet may be positioned to remove liquid from substantially the centre of the sedimentation vessel in a horizontal plane. The inlet to the fluid outlet may be positioned along substantially the same axis as one or more of (especially all of): the aperture in the sedimentation vessel bottom wall, the aperture in the agglomeration vessel upper wall, and the floe outlet. The inlet to the fluid outlet may be positioned below a weir for removal of matter that floats on or is less dense than the liquid to be clarified.

[0056] It may be advantageous to position the fluid outlet below a weir, and to position the fluid outlet along substantially the same axis as one or more of (especially all of): the aperture in the sedimentation vessel bottom wall, the aperture in the agglomeration vessel upper wall, and the floe outlet. In particular, the fluid level in the sedimentation vessel may be highest along an axis that connects one or more of the aperture in the sedimentation vessel bottom wall, the aperture in the agglomeration vessel upper wall, and the floe outlet (as a column of water may rise through the clarifier through the apertures in the sedimentation vessel bottom wall and the agglomeration vessel upper wall). Accordingly, the fluid outlet may be positionable closest to the height of the weir at this point, whilst minimising the potential ingress of matter that floats on or is less dense than the liquid to be clarified.

[0057] The fluid outlet may be adjustably positionable in the sedimentation vessel. The fluid outlet may be positionable at varying distances relative to the upper or bottom walls of the sedimentation vessel.

[0058] The fluid outlet may include a vortex breaker. The vortex breaker may be positioned at the inlet of the fluid outlet. The vortex breaker may be a diffuser plate. The vortex breaker may include at least one side wall and a lower wall. The lower wall may be substantially solid. The at least one side walls may define a plurality of apertures for ingress of liquid into the fluid outlet. The lower wall may be positioned perpendicularly to the direction of fluid flow into the fluid outlet. A vortex breaker may be advantageous to decrease the size of or ameliorate the formation of vortices which may form in the sedimentation vessel, especially at higher flow rates. A vortex breaker may prevent or ameliorate the fluid outlet drawing fluid from deeper within the sedimentation chamber, so that fluid exiting the clarifier has more time to settle.

[0059] The fluid outlet may extend through the upper wall or the at least one side wall of the sedimentation vessel. The fluid outlet may include a conduit which increases in diameter as it travels further from the sedimentation vessel. This configuration may be advantageous, especially if a pump is in fluid connection with the fluid outlet. A larger diameter conduit or pipe further away from the sedimentation vessel may assist in creation of a siphon effect to draw clarified liquid out of the sedimentation vessel, and may assist in ameliorating cavitation issues at the fluid outlet.

[0060] The fluid outlet may include a floe collection chamber for collection of floe. In one embodiment, the fluid outlet is positioned to extend downwardly into the fluid in the sedimentation vessel. In one embodiment, the fluid outlet is positioned at substantially the centre of the sedimentation chamber in a lateral (or horizontal) plane. In one embodiment, the floe collection chamber is located substantially above the flow of fluid passing through the fluid outlet.

[0061] In another embodiment, the fluid outlet includes a first portion having a first and a second end, and a second portion having a first and a second end, wherein the first end of the second portion is in fluid communication with the first portion (especially with the first portion intermediate the first and second ends), and wherein the first end of the first portion provides an inlet for fluid into the fluid outlet, wherein the second end of the first portion provides the floe collection chamber, and wherein fluid exiting the fluid outlet flows outwardly through the second end of the second portion. In one embodiment, the first portion is a substantially vertically extending portion. In another embodiment, the second portion is a substantially horizontally extending portion. In a further embodiment, the second end of the first portion is sealed.

[0062] The sedimentation vessel may include a weir for removal of matter that floats on or is less dense than the liquid to be clarified. The weir may be positioned above the fluid outlet. The weir may be in the form of a laterally extending opening in the at least one side wall of the sedimentation vessel. The laterally extending opening may extend in substantially the same plane as the upper surface of the liquid in the sedimentation vessel. The weir may be located in an upper portion of the sedimentation vessel. A shroud may be positioned over the weir. The sedimentation vessel may include a conduit connected to the shroud or weir for removal of fluid passing over the weir. The conduit may include a funnel portion and/or a pipe. The funnel portion may direct fluid passing over the weir into the pipe. The conduit may connect the weir to a centrifuge or settling tank for separation of the hydrocarbons.

[0063] The sedimentation vessel may include a vent in the upper wall. The vent may be in the form of a inverse U-shaped pipe. The vent may be to avoid pressurising the clarifier, and to allow any excess air in the clarifier to escape.

[0064] The sedimentation vessel may include an access opening in the upper wall. The access opening may be a man-hole.

[0065] The clarifier may include a bleed conduit for removal of trapped matter in the agglomeration vessel. The trapped matter may be, for example, matter that is less dense than the liquid to be clarified (such as hydrocarbons), gas or floating matter. The bleed conduit may extend through at least one side wall of the agglomeration vessel (this may be a lower portion of the bleed conduit). The bleed conduit may extend through an upper portion of the at least one side wall of the agglomeration vessel (this may be an upper portion of the bleed conduit). The bleed conduit may allow removal of the trapped matter from the clarifier, or it may allow the trapped matter to be transferred to the sedimentation vessel. In one embodiment, the bleed conduit connects the agglomeration vessel and the sedimentation vessel. An upper end of the bleed conduit may extend through at least one side wall of the sedimentation vessel, especially through an upper portion of the at least one side wall of the agglomeration vessel. In another embodiment, trapped matter removed from the agglomeration vessel may be returned to the liquid to be clarified (prior to entry into the agglomeration vessel).

[0066] The lower end of the bleed conduit may extend through the at least one side wall of the agglomeration vessel at any suitable angle. In one embodiment, the lower end of the bleed conduit extends from the at least one side wall of the agglomeration vessel at an angle of 30 to 90 ° from the side wall, especially at an angle of about 30 ° or about 90 °. The lower end of the bleed conduit may extend from the at least one side wall of the agglomeration vessel at the same angle as the upper wall of the agglomeration vessel. Advantageously, the lower end of the bleed conduit may be angled to facilitate the exit of gas from the agglomeration vessel.

[0067] The upper end of the bleed conduit may also extend through the at least one side wall of the sedimentation vessel at any suitable angle. In one embodiment, the upper end of the bleed conduit extends through the at least one side wall of the sedimentation vessel substantially perpendicularly. The clarifier may also include a splash guard in the sedimentation vessel to prevent liquid in the sedimentation vessel from splashing into the bleed conduit. [0068] The clarifier may include at least one cleaning system. The at least one cleaning system may be one cleaning system. The at least one cleaning system may include a fluid inlet for a cleaning fluid, and a fluid outlet within the clarifier for exit of cleaning fluid. The cleaning fluid may be an aqueous fluid, especially water. The fluid outlet may be at least one (especially a plurality) of nozzles positioned within the clarifier, especially at least one nozzle positioned on an upper wall of the sedimentation vessel. The cleaning system may include at least one strainer (especially at least one mesh strainer) located intermediate the fluid inlet and the fluid outlet.

[0069] The clarifier may include at least one sampling conduit. The at least one sampling conduit may extend through a wall of the sedimentation vessel or the agglomeration vessel. In one embodiment, the at least one sampling conduit is a plurality of sampling conduits, and may especially extend through at least one side wall of the agglomeration vessel and/or at least one side wall of the sedimentation vessel. The at least one sampling conduit may include a valve.

[0070] The clarifier may include more than one sedimentation vessel. In one embodiment, the clarifier includes an intermediate sedimentation vessel, located between the agglomeration vessel and the sedimentation vessel. The intermediate sedimentation vessel may have a bottom wall, an upper wall opposite to the bottom wall and at least one side wall. Features of the bottom wall, the upper wall and the at least one side wall may be as described above for the sedimentation vessel. In this embodiment, the upper wall of the intermediate sedimentation vessel may be integrally formed with the bottom wall of the sedimentation vessel. The at least one side wall of the agglomeration vessel, the sedimentation vessel and the intermediate sedimentation vessel may be integrally formed. The upper wall of the intermediate sedimentation vessel may define a plurality of apertures. The plurality of apertures may be located proximate to the at least one side wall of the intermediate sedimentation vessel. At least one of the plurality of apertures may be located in the centre of the upper wall (to allow floe sediment to pass from the sedimentation vessel into the intermediate sedimentation vessel). Fluid may pass from the intermediate sedimentation vessel to the sedimentation vessel via the plurality of apertures. The aperture(s) may be of adjustable size.

[0071] The clarifier of the present invention may be portable. In one embodiment, the clarifier has a footprint of 2-4 m in width, of 2-4 m in depth, and 5-10 metres in height. The clarifier may be locatable on a trailer or skid.

[0072] The clarifier may include at least one chemical vessel for holding a chemical. The chemical vessel may be a coagulant vessel for holding a coagulant. The coagulant may be a chemical coagulant and/or a flocculant. The chemical coagulant may be a polymer. The polymer may be anionic or cationic. Exemplary polymers would be known to a skilled person. An exemplary polymer is a poly-aluminium chloride (PAC). The coagulant may be added in any suitable amount. The coagulant may be added at a concentration of, for example up to 0.01 %, especially up to 0.005%, or up to 0.002% by weight.

[0073] In another embodiment, the chemical vessel maybe a pH adjuster vessel for holding a pH adjuster. The pH adjuster may be an acid or a base. Control of the pH through application of a pH adjuster may allow an operator greater control of floe formation and sedimentation within the clarifier.

[0074] The clarifier may be configured to introduce the chemical into the liquid to be clarified at any suitable point. For example, the at least one chemical vessel may include a conduit extending to the agglomeration vessel, to introduce the chemical into the clarifier within the agglomeration vessel. In another example, the chemical vessel may include a conduit extending to a conduit connected to the fluid inlet, so that the chemical is mixed with the fluid to be treated before entering the agglomeration vessel. In a further example, a holding tank may hold the liquid to be clarified and the chemical vessel may include a conduit extending to the holding tank for holding the liquid.

[0075] In one embodiment, the fluid to be clarified has exited an electrochemical treatment apparatus for electrochemical treatment of the liquid. An exemplary electrochemical treatment apparatus is described in WO2015/176136. Liquid exiting the electrochemical treatment apparatus may have a high zeta potential, resulting in an increased affinity for the coagulant.

[0076] The clarifier may also include a temperature adjuster for adjusting the temperature of the liquid to be clarified. The temperature adjuster may heat or cool the liquid to be clarified. The temperature adjuster may be configured to adjust the temperature of the liquid before entry into the clarifier.

[0077] The clarifier may include a ballast introducer for introducing ballast into the clarifier. Any suitable ballast may be used. For example, the ballast may be sand, especially fine sand, most especially sand of approximately 100 μηι. The ballast may also be a magnetic ballast, such as magnetite. The floe may adhere to the ballast, assisting in the agglomeration of floe. The ballast introducer may include a conduit extending through at least one side wall or the bottom wall of the agglomeration vessel. The ballast introducer may include a conduit extending through at least one side wall or the upper wall of the sedimentation vessel.

[0078] The clarifier may include at least one filter. The at least one filter may be positioned between the agglomeration vessel and the sedimentation vessel (for example, over the aperture in the upper wall of the agglomeration vessel), or at the inlet to the fluid outlet. The filter could be a fabric or membrane filter, for example a geofabric or a polyethylene terephthalate filter (such as Dacron™).

[0079] The clarifier may include at least one support for supporting the clarifier. The support may be a frame. The frame may be of any suitable shape. The frame may include a plurality of vertical members and horizontal members. The vertical and horizontal members may be fastened together, for example, by welding, clinching (press joining), or by use of fasteners (such as screws, bolts and/or rivets). The frame may include one or more projections which may define an aperture. The projections may be for tying down the frame. The frame may include one or more outriggers for stabilising the frame. The one or more outrigggers may telescopically extend from the base of the frame. The one or more outriggers may be four outriggers, with each outrigger extending from a corner of the frame. The one or more outriggers may each include a foot. The foot may be removably attachable to each outrigger, especially to the end of each outrigger. The foot may have greater width than the outrigger for further stabilising the frame. The support may include a caged ladder for an operator to climb the clarifier.

[0080] The agglomeration vessel and the sedimentation vessel may be mounted to the support in any suitable way. In one embodiment, the agglomeration vessel and the sedimentation vessel includes one or more anchors welded to an exterior side wall of the agglomeration vessel and/or the sedimentation vessel, and the one or more anchors are fastenable to the support, especially to horizontal members of a frame.

[0081] The liquid to be clarified may be an aqueous solution, especially water.

[0082] The clarifier may be made of any suitable material including metal (such as steel) and plastic (such as PVC).

[0083] In a fifth aspect, the present invention relates to a liquid purification system including a clarifier of the first to fourth aspects of the present invention. The liquid purification system may include more than one clarifier of the first to fourth aspects of the present invention, especially two clarifiers of the first to fourth aspects of the present invention. If more than one clarifier is present in the liquid purification system, the clarifiers may be in series or parallel. If the clarifiers are in series, it may be advantageous to operate the clarifiers at different speeds (as at higher speeds the clarifier may provide increased agglomeration, whereas at lower speeds the clarifier may provide increased sedimentation). If the clarifiers are in series different coagulants may be used with each clarifier.

[0084] The liquid purification system may also include an electrochemical apparatus for electrochemically treating a liquid (an exemplary electrochemical apparatus is described in WO2015/176136). The liquid purification system may also include a media filtration unit (the media in the media filtration unit may be, for example, sand, anthracite, glass or diatomaceous earth; especially glass), a polishing filter (which may include a fabric filter), or at least one membrane filter (such as an ultrafiltration, nanofiltration or reverse osmosis unit). The liquid purification system may include a temperature adjuster (as described above), at least one chemical vessel (as described above) or a holding tank (as described above). The liquid purification system may include a screw press in fluid communication with the floe outlet of the clarifier. The liquid purification system may include a hydrocyclone in fluid communication with the floe outlet of the clarifier (especially for removal of ballast from the floe). The liquid purification system may include a centrifuge or tank in fluid communication with the weir from the sedimentation vessel. The conduit from the weir from the sedimentation vessel may also be in fluid communication with the inlet to the electrochemical apparatus for electrochemical treatment of liquids. The liquid purification system may include a magnet for separation of magnetic ballast.

[0085] In one embodiment, the liquid purification system includes an electrochemical apparatus for electrochemically treating a liquid. The outlet of the electrochemical apparatus may be in fluid communication with the fluid inlet of a clarifier according to the first to fourth aspects of the present invention. The fluid outlet of the clarifier according to the first to fourth aspects of the present invention may be optionally in fluid communication with the fluid inlet of a second clarifier according to the first to fourth aspects of the present invention. The fluid outlet of the second clarifier (if present), or the fluid outlet of the clarifier of the first to fourth aspects of the present invention may be in fluid communication with the inlet of a media filtration unit. The outlet of a media filtration unit may be in fluid communication with the inlet of at least one membrane filter.

[0086] In a sixth aspect, the present invention relates to a method of clarifying a liquid using the clarifier of the first to fourth aspects of the present invention, or to a method of purifying a liquid using the liquid purification system of the fifth aspect of the present invention. The method may includes the step of introducing (especially pumping) a liquid into the fluid inlet of the clarifier of the first to fourth aspects of the present invention. The method may include the step of varying the velocity at which the liquid is pumped into the fluid inlet. The method may include the step of tangentially introducing a liquid to be clarified into the agglomeration vessel. The method may include the step of creating a centrifugal force in the agglomeration vessel. The method may include the step of applying non-uniform centrifugal forces on the liquid to be clarified in the agglomeration vessel. The method may include the step of rotating a barrier extending from at least one side wall of the agglomeration vessel.

[0087] The method may include the step of removing clarified liquid from the fluid outlet. The method may include the step of removing agglomerated floe from the floe outlet. The method may include the step of pumping agglomerated floe from the floe outlet to a dewatering device, such as a screw press. The method may include the step of removing matter that floats on or is less dense than the liquid to be clarified via the weir. The method may include the step of transferring matter that floats on or is less dense than the liquid to be clarified from the weir to a centrifuge, to a settling tank or to an electrochemical apparatus for electrochemical treatment of a liquid.

[0088] The method may include the step of removing trapped matter from the agglomeration vessel via a bleed conduit. The trapped matter may be removed to the liquid to be clarified, or to the sedimentation vessel.

[0089] The method may include the step of sampling the liquid in the clarifier using at least one sampling conduit.

[0090] The method may include the step of adding a chemical to the liquid to be clarified, or to the liquid in the clarifier. The chemical may be, for example, a coagulant or a pH adjuster. The method may include the step of introducing ballast into the clarifier. The method may include the step of removing ballast from the agglomerated floe. The method may include the step of adjusting the temperature of the liquid to be introduced into the clarifier, or of the liquid within the clarifier.

[0091] The method may include the step of electrochemically treating a liquid, and then transferring (especially pumping) the electrochemically treated liquid into the clarifier of the first to fourth aspects of the present invention.

[0092] The method may include the step of media filtering the clarified liquid. The method may include the step of subjecting the clarified liquid to polishing filtration and/or to membrane filtration. [0093] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

BRIEF DESCRIPTION OF DRAWINGS

[0094] Examples of the invention will now be described by way of example with reference to the accompanying Figures, in which:

[0095] Figure 1 shows a top view of an example clarifier;

[0096] Figure 2 shows a side view of the example clarifier of Figure 1 , from view A-A as shown in Figure 1 with the support omitted;

[0097] Figure 3 shows a side view of the example clarifier of Figure 1, from view B-B as shown in Figure 1 with the support omitted;

[0098] Figure 4 shows a side view of bleed conduit (see Figure 2) of the example clarifier of Figure 1;

[0099] Figure 5 shows a side view of the upper wall of the agglomeration vessel (see Figures 2 and 3) of the example clarifier of Figure 1;

[00100] Figure 6 shows the fluid outlet of the example clarifier of Figure 1;

[00101] Figure 7 shows a cross sectional view through C-C of the fluid outlet of Figure 6, showing the position of the support;

[00102] Figure 8 shows a cross sectional view through D-D of the fluid outlet of Figure 6; [00103] Figure 9 shows a portion of the fluid outlet of Figure 6;

[00104] Figure 10 shows an exemplary anchor welded to a side wall of the agglomeration vessel of the clarifier of Figure 1 ;

[00105] Figure 11 shows a side view of the clarifier of Figure 1 including a support;

[00106] Figure 12 shows the support of Figure 11;

[00107] Figure 13 shows a top view of the clarifier of Figure 11;

[00108] Figure 14 shows a cross sectional view through E-E of the clarifier of Figure 11 ; [00109] Figure 15 shows a bottom view of the clarifier of Figure 11, with the outriggers telescopically extended;

[00110] Figure 16 shows a side view of the base of support of Figure 15;

[00111] Figure 18 shows a side view of the end of an outrigger with a foot attached;

[00112] Figure 19 shows a top view of the end of the outrigger of Figure 18;

[00113] Figure 20 is a process flow diagram for purification of a liquid;

[00114] Figure 21 shows a side view of an alternative bleed conduit; and

[00115] Figure 22 shows a side view of a valve plate affixed to the support of Figure 11.

[00116] Preferred features, embodiments and variations of the invention may be discerned from the following Description which provides sufficient information for those skilled in the art to perform the invention. The following Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way.

DESCRIPTION OF EMBODIMENTS

[00117] Embodiments of the present invention will now be described with reference to Figures 1 to 22. In the figures, like reference numerals refer to like features.

[00118] Figures 1 to 19, 21 and 22 illustrate a clarifier 1 for clarifying a liquid, or to components or parts thereof.

[00119] As shown in Figures 2 and 3, the clarifier 1 includes an agglomeration vessel 10 for agglomeration of floe, and a sedimentation vessel 30 for sedimentation of floe. The sedimentation vessel 30 is in fluid communication with the agglomeration vessel 10. The agglomeration vessel 10 includes a fluid inlet 12 for tangentially introducing a liquid to be clarified into the agglomeration vessel 10, and a bottom wall 18 including a floe outlet 16 for removal of floe sediment.

[00120] The sedimentation vessel 30 includes a fluid outlet 32 for clarified liquid. The sedimentation vessel 30 also includes a weir 40 positioned above the fluid outlet 32 for removal of matter that floats on or is less dense than the liquid to be clarified.

[00121] As shown in Figure 3, the agglomeration vessel includes a bottom wall 18, an upper wall 20 opposite to the bottom wall, and a side wall 22 extending between the bottom wall 18 and the upper wall 20. The side wall 22 is substantially circular and extends vertically. The side wall 22 is about 2.4 metres (about 7 feet, 9.5 inches) in diameter and about 1.5 metres (5 feet) in height.

[00122] The bottom wall 18 is declined from the side wall 18 to the floe outlet 16 for removal of floe sediment. The bottom wall 18 is angled at about 60° from the horizontal and at about 150° from the side wall 22. The bottom wall 18 is substantially inversely conical and is adapted to direct agglomerated floe to the floe outlet 16. The bottom wall is about 2 metres (about 6 feet, 7.25 inches) high, and extends from a diameter of about 2.4 metres (about 7 feet, 10 inches) to a diameter of about 0.06 metres (about 2 3/8 inches). The floe outlet 16 is positioned at substantially the centre of the bottom wall 18. The floe outlet 16 is about 0.06 metres (about 2 3/8 inches) wide.

[00123] As shown in Figures 3 and 5, the upper wall 20 defines an aperture 20c which is substantially centrally located in the upper wall 20. The upper wall 20 is declined from the side wall 22 towards the aperture 20c at 20a. The declined portion of the upper wall 20 forms a conical portion 20a, which is positioned inversely. The conical portion 20a is declined from the side wall 22 towards the central aperture 20c at an angle of about 30° from the vertical or from the side wall 22 (about 60 ⁰ from the horizontal). The conical portion extends for about 1.15 metres (about 3 feet, 8 7/8 inches).

[00124] The upper wall 20 also includes a cylindrical portion 20b which is connected to conical portion 20a. The cylindrical portion 20b is about 0.45 metres (about 1 foot, 6 inches) in length and extends into the agglomeration vessel 10. The cylindrical portion 20b extends substantially parallel to the side wall 22 and substantially vertically. The aperture 20c defined in the upper wall 20 at the centre of the conical portion 20a and the cylindrical portion 20b is about 1.2 metres (about 4 feet) in diameter. The upper wall 20 also includes inclined portion 20d which is inclined at an angle of 45° relative to the cylindrical portion 20b. The inclined portion extends for about 0.1 metres (about 4 inches). The inclined potion 20d is to improve the rigidity of the cylindrical portion 20b, and the inclined portion 20d may also be angled inwardly (instead of outwardly as illustrated in Figure 5).

[00125] As shown in Figures 3 and 12, the fluid inlet 12 extends through the side wall 22 of the agglomeration vessel 10. The clarifier 1 of Figures 1 to 19 incudes one fluid inlet 12. The fluid inlet 12 is for tangentially introducing a liquid to be clarified into the agglomeration vessel 10. The fluid inlet 12 is in the form of a pipe extending into the agglomeration vessel 10. The terminal end 14 of the pipe is angled to direct the liquid to be clarified substantially parallel to the side wall 22. The terminal end of the fluid inlet is angled to direct the liquid at about 0° relative to the side wall 22 and substantially perpendicularly to the centre of the agglomeration vessel 10. The terminal end 14 of the fluid inlet 12 is a pipe of a diameter of about 0.05 metres (2 inches).

[00126] The tangential introduction of the liquid to be clarified into the agglomeration vessel 10 assists in creating a cyclone effect (or centrifugal force) within the agglomeration vessel 10, with the liquid moving closest to the side wall 22 moving more quickly than liquid moving towards the centre of the agglomeration vessel 10. As the aperture 20c is centrally positioned, the liquid departing the agglomeration vessel 10 through the aperture 20c is the most slowly moving liquid in the agglomeration vessel, minimising turbulence within the sedimentation vessel 30.

[00127] The centrifugal rotation of the liquid in the agglomeration vessel 10, together with the declined bottom wall 18 assists in the agglomeration of floe, as the centrifugal force drives the floe up the declined wall 18, whilst gravity assists the floe to travel down the wall 18. Consequently, floe which travels to the bottom of the wall 18 is likely to have agglomerated to at least a defined size.

[00128] Similarly, the conical portion 20a of the upper wall 20 ameliorates the possibility of such particles escaping the agglomeration vessel 10 and acts to drive the liquid to be clarified downwards, towards the bottom wall 18.

[00129] The sedimentation vessel 30 is positioned directly above the agglomeration vessel 10 and is in fluid communication with the agglomeration vessel 10 via the aperture 20c. The fluid in the sedimentation vessel 30 is intended to be less turbulent, which allows the floe to settle.

[00130] The sedimentation vessel 30 includes a bottom wall 44, an upper wall 46 opposite the bottom wall 44 and a side wall 48 extending between the bottom wall 44 and the upper wall 46. The side wall 48 is substantially circular and is integral with the agglomeration vessel 10 side wall 22. The side wall 48 is about 1.9 metres (about 6 feet, 3 3/8 inches) high and about 2.4 metres (about 7 feet, 10 inches) in diameter. The upper wall 46 is substantially planar.

[00131] The bottom wall 44 of the sedimentation vessel 30 is the upper wall 20 of the agglomeration vessel 10. Accordingly upper wall conical portion 20a is also bottom wall conical portion 44a. Upper wall cylindrical portion 20b is also bottom wall cylindrical portion 44b. Upper wall aperture 20c is also bottom wall aperture 44c, and upper wall inclined portion 20d is also bottom wall inclined portion

[00132] The bottom wall 44 of the sedimentation vessel 30 is adapted to direct floe sediment to the aperture 44c. In particular, as floe settles in the sedimentation vessel 30, it descends to bottom wall 44, where it tumbles down conical portion 44a and into central aperture 44c to pass into the agglomeration vessel 10 and to floe outlet 16.

[00133] The fluid outlet 32 is for clarified liquid and is positioned in the upper portion of the sedimentation vessel 30. The fluid outlet is positioned to remove liquid from substantially the centre of the sedimentation vessel 30 in a horizontal plane. The inlet 33 to the fluid outlet 32 is positioned along substantially the same axis as aperture 44c, aperture 20c, and floe outlet 16. The inlet 33 to the fluid outlet 32 is positioned below a weir 40 for removal of matter that floats on or is less dense than the liquid to be clarified. The inlet 33 to the fluid outlet 32 is approximately 0.2 m (about 8 inches) in diameter.

[00134] The fluid outlet 32 includes a vortex breaker 34 positioned at the inlet 33 of the fluid outlet 32. The vortex breaker 34 includes a side wall 34a defining a plurality of apertures (for ingress of clarified liquid into the fluid outlet 32) and a substantially solid lower wall 34b (see Figure 6). The lower wall 34b is positioned perpendicular to the direction of fluid flow into the fluid outlet 32. The lower wall 34b is about 0.3 metres (about 12 inches) in diameter.

[00135] The fluid outlet 32 extends through side wall 48 of the sedimentation vessel 30. The fluid outlet includes a smaller diameter conduit 36 (approximately 0.2 metres (about 8 inches) in diameter) and a larger diameter conduit 38 (approximately 0.3 metres (about 12 inches) in diameter). The larger diameter conduit 38 assists in the creation of a siphon effect to draw clarified liquid out of the sedimentation vessel 30 and assists in ameliorating cavitation issues at the fluid outlet 32. The larger diameter conduit 38 includes an outlet 39 perpendicular to the conduit 38, and a test port 37 which may be sealed with a bung (see Figure 9).

[00136] The clarifier 1 may include a cleaning system (not shown) which includes a fluid inlet for a cleaning fluid, and a fluid outlet in the form of a plurality of nozzles located within the clarifier on an upper wall 46 of the sedimentation vessel. A mesh strainer may be positioned between the fluid inlet and the fluid outlet.

[00137] The weir 40 is in the form of a laterally extending opening in side wall 48. A shroud 41 sits over the weir 40. A conduit 42 is connected to the shroud 41 and includes a pipe 42a. The weir 40 is for removal of matter that floats on or is less dense than the liquid to be clarified. [00138] The upper wall 46 includes a vent 50 in the form of an inverse U-shaped pipe. The vent allows the clarifier to remain at atmospheric pressure and allows any excess air to escape.

[00139] The upper wall 46 also includes an access opening 52 in the form of a man-hole to permit access into the clarifier 1.

[00140] The walls 46, 48, 22, 18 of the clarifier 1 may be made of ¼ inch thick metal, especially mild (or carbon) steel. However, the walls 46, 48, 22, 18 of the clarifier 1 may be made of plastic. The pipes and conduits in the clarifier 1 may be made of stainless steel or plastic (especially PVC).

[00141] The clarifier 1 also includes a bleed conduit 60 for removal of trapped matter in the agglomeration vessel 10 (see Figure 4). The bleed conduit has a lower portion 60a which extends through the side wall 22 of the agglomeration vessel, and an upper portion 60b that extends through an upper portion of the sedimentation vessel 30 side wall 48. The bleed conduit 60 allows removal of trapped matter (such as less dense matter, floating matter or gas in the agglomeration vessel) from the agglomeration vessel 10. In the bleed conduit 60 shown in Figure 4, the lower portion 60a extends through the side wall 22 of the agglomeration vessel perpendicularly, and the upper portion 60b extends through an upper portion of the sedimentation vessel 30 side wall 48 perpendicularly. A variant is shown in Figure 21. As shown in this Figure, the lower portion 600a of the bleed conduit 600 extends through the side wall 22 of the agglomeration vessel at 60 ° from the horizontal or 30 ° from the side wall (i.e. at substantially the same angle as the conical portion 20a). The upper portion 600b extends through an upper portion of the sedimentation vessel 30 side wall 48 perpendicularly. As shown in Figure 21, there is also a splash guard 650, in the form of a 3/16 inch x 6 inch plate attached to upper wall 46 about 1.5 inches from the side wall 30.

[00142] The clarifier 1 includes three sampling conduits 62a, 62b and 62c (see Figure 3). All three sampling conduits include valves. The sampling conduits separately terminate and do not connect. A first sampling conduit 62a extends through an upper side wall 48 of the sedimentation vessel 30, a second sampling conduit 62b extends through a lower side wall 48 of the sedimentation vessel 30, and a third sampling conduit 62c extends through the bottom wall 18 of the agglomeration vessel 10.

[00143] A plurality of anchors 64 are welded to the side walls 22, 48. As shown in Figures 1 and 14, the clarifier 1 includes four anchors 64 welded at each of two heights on the exterior side walls 22, 48. [00144] The anchors 64 are fastenable to a support 70 in the form of a frame. The frame 70 includes four vertical members 72 and sixteen horizontal members 74 joined together. The frame 70 includes a plurality of projections which each define an aperture 76, which act as tie- down points for the frame 70.

[00145] The base of the frame includes four outriggers 78 for stabilising the frame (see Figures 15 and 16). The outriggers 78 are for stabilising the frame 70. The outriggers 78 telescopically extend from horizontal members 74, and the outriggers 74 include a handle 79 for pulling the outrigger 78 from the horizontal members 74 (see Figure 17). A foot 80 may be removeably attachable to the end of each outrigger 78 (see Figures 18 and 19). The foot 80 has a greater width than the outrigger 78 for further stabilising the frame.

[00146] The clarifier 1 of Figures 1-19 and 21 is portable and may be locatable on a trailer or skid. The clarifier is about 2.6 metres (102 inches) wide and deep and about 6 metres (240 inches) high. A caged ladder may be affixed to the side of the clarifier 1.

[00147] The clarifier 1 may include a valve plate 700, as shown in Figure 22. The valve plate may be positioned across two vertical members 72 of the frame 70. The valve plate may include ports to which various pipes and conduits are connected. For example, large diameter conduit 38 of fluid outlet 32 may be connected at 708; fluid inlet 12 may be connected at 706; floe outlet 16 may be connected at 704; and pipe 42a may be connected at 702.

[00148] In use, the fluid inlet 12 is connected to a variable speed pump to pump the liquid into the clarifier. The variable speed pump pumps the liquid to be clarified into the clarifier at an oscillating velocity to introduce the liquid to be clarified into the agglomeration vessel 10 in a pulsed manner. The liquid to be clarified is especially electrochemically treated liquid from an electrochemical treatment apparatus. Prior to entry into the agglomeration vessel a chemical (such as a coagulant) may be added to the liquid to be clarified.

[00149] In use, the floe outlet 16 is connected to a rotary valve which rotates as agglomerated floe settles in the valve. From the rotary valve, the floe enters a dewatering device, such as a screw press. The floe outlet may be under negative pressure to prevent air entering the clarifier 1 at this point.

[00150] In use, the fluid exiting the clarifier 1 at the weir 40 may pass to a centrifuge or to a settling tank for separation of hydrocarbons, or to an electrochemical treatment device for electrochemical treatment of the fluid. [00151] In use, the fluid exiting the clarifier 1 at the fluid outlet 32 may be subjected to further purification such as by media filtration, ultrafiltration, nanofiltration or reverse osmosis.

[00152] An exemplary fluid process diagram is illustrated in Figure 20. First, liquid is subjected to electrochemical treatment 100. The electrochemically treated liquid has a high zeta potential and a high affinity for coagulants. A coagulant is then added to the electrochemically treated liquid, and the liquid is pumped into the clarifier of Figures 1-19 for clarification 110. The pump varies the velocity at which the liquid is pumped into the clarifier, resulting in nonuniform centrifugal forces in the agglomeration vessel 10 and improved agglomeration of floe. Liquid exiting via the weir 40 may be returned to electrochemical treatment 100. Clarified liquid exiting the clarifier 1 via fluid outlet 32 is filtered through a media at 120, such as glass. At this point the filtered liquid may be suitable for use. Otherwise, the filtered liquid may be subjected to further filtration, such as through a polishing membrane (which may include a fabric filter) 130, through ultrafiltration 140, through nanofiltration 150 or through reverse osmosis 160.

[00153] The group of electrochemical treatment apparatus, clarifier 1, media filtration unit, polishing filter, and membrane filter (such as ultrafiltration, nanofiltration or reverse osmosis) together form a liquid purification system.

[00154] Reference throughout this specification to One embodiment' or 'an embodiment' means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases 'in one embodiment' or 'in an embodiment' in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[00155] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described includes preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

ADVANTAGES OF THE INVENTION

[00156] In various embodiments, the preferred embodiment of the present invention may advantageously provide one or more of the advantages listed below: Reduced footprint compared with prior art clarifiers. By positioning the agglomeration and sedimentation vessels in a vertical relationship, the footprint may be minimised. This improves the portability of the clarifier.

The clarifier may be controlled by adjusting the flow rate of liquid entering the clarifier, and by adjusting the addition of coagulant or ballast.

No moving mechanical parts, which decreases maintenance costs.

Allow separation of hydrocarbons and floe from other floating particles and liquid (such as water)

CITATION LIST

WO2015/176136