GB2641739A

GB2641739A - Fluid treatment apparatus

Info

Publication number: GB2641739A
Application number: GB2408267.9A
Authority: GB
Inventors: Martin Mulligan Sean; George Leonard Peter; Lawrence Carty Alan; Michael Clifford Fergus; Fionn Mannion Paul
Original assignee: Vortech Water Solutions Ltd
Current assignee: Vortech Water Solutions Ltd
Priority date: 2024-06-10
Filing date: 2024-06-10
Publication date: 2025-12-17
Also published as: GB202408267D0; AU2024204235B1; WO2025257112A1

Abstract

A fluid treatment apparatus 100 with a first fluid intake duct 104 which defines a first fluid inlet port 106 for fluid communication with a first fluid source 200. The first fluid intake duct 104 defines a pump access port 120 provided spaced apart from the first fluid inlet port 106 along a longitudinal axis 112 of the first fluid intake duct 104. A first fluid pump mount 128 is provided which defines a pumping position 126 in the first fluid intake duct 104 between the first fluid inlet port 106 and the pump access port 120. The first fluid intake duct 104 defines a first pump guide path 122 configured for the first fluid pump 400 to translate along between the first fluid pump mount 128 to the pump access port 120. The pump access port 120 may be configured to enable the passage of a first fluid pump 400 therethrough. A flotation unit 2000 may be provided for supporting a fluid treatment apparatus 100 a first fluid reservoir 702 containing a first fluid 202.

Description

[0001] FLUID TREATMENT APPARATUS

[0002] The present disclosure relates to a fluid treatment apparatus. Background Effective mixing of different fluids is a requirement in various industries.

[0003] A particular example of fluid mixing relates to wastewater treatment which may involve aeration carried out in a biological treatment process. More generally, mixing may be carried out in the presence or absence of aeration as part of wastewater treatment to keep particles in suspension in, for example, an aerobic or anoxic treatment process.

[0004] The apparatus used for carrying out such wastewater treatment typically comprises at least one pump for moving the fluid to be treated. The location of the pump in the apparatus, how the apparatus is mounted in the pump, and/or how the depth of the pump in the fluid being treated is maintained may all be key considerations in the configuration of the apparatus.

[0005] For maximum efficiency, and to ensure fluid is drawn from a desired depth in the wastewater, the pump may need to be submerged in the fluid. This is because any duct work upstream of the pump inlet or downstream of the pump outlet may increase pressure losses and hence reduce efficiency. However, in a configuration in which the pump is located in the fluid, maintenance is inherently more difficult. For example, working on the pump while it is submerged may be hazardous, or at least very difficult, for an operator. The drainage of a wastewater reservoir to allow an operator to access or retrieve the pump may result in a long down time of the wastewater treatment apparatus.

[0006] Hence a fluid treatment apparatus with a configuration which enables its associated pump to operate at maximum efficiency while also having a configuration in which its associated pump is easily accessible and/or replaceable, is highly desirable.

[0007] Summary

[0008] According to the present disclosure there is provided a fluid treatment apparatus, a fluid treatment system and a floating platform as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

[0009] Accordingly, there may be provided a fluid treatment apparatus (100). The fluid treatment apparatus (100) may comprise a housing (102) which defines a first flow path (114). The housing (102) may comprise a first fluid intake duct (104) which defines a first fluid inlet port (106) for fluid communication with a first fluid source (200). The first fluid intake duct (104) may define a longitudinal axis (112).

[0010] The first fluid intake duct (104) may comprise a pump access port (120). The pump access port (120) may be provided spaced apart from the first fluid inlet port (106) along the longitudinal axis (112) of the first fluid intake duct (104).

[0011] The first fluid intake duct (104) may comprise a first fluid pump mount (128) which defines a pumping position (126) in the first fluid intake duct (104) between the first fluid inlet port (106) and the pump access port (120).

[0012] The first fluid intake duct (104) may define a first pump guide path (122) configured for a first fluid pump (400) to translate along between the first fluid pump mount (128) to the pump access port (120).

[0013] The pump access port (120) may be configured to enable the passage of a first fluid pump (400) therethrough.

[0014] The housing may comprise a second fluid inlet port (108) for fluid communication with a second fluid source (300). The housing may comprise a fluid outlet port (110) for fluid delivery to the first fluid source (200). The second fluid inlet port (108) may be located along the first flow path (114) between the first fluid inlet port (106) and the fluid outlet port (110).

[0015] The fluid treatment apparatus (100) may further comprise a first fluid pump (400).

[0016] In a first mode of operation the first fluid pump (400) may be engaged with the first fluid pump mount (128) to thereby locate the first fluid pump (400) at the pumping position (126) within the first fluid intake duct (104). In a first mode of operation the first fluid pump (400) may be in fluid communication with the first fluid source (200) via the first fluid inlet port (106).

[0017] In a second mode of operation the first fluid pump (400) may be operable to travel along the first pump guide path (122) from the pumping position (126) to, and through, the pump access port (120).

[0018] In the first mode of operation the first fluid pump (400) may be operable to be in an operational mode to pump a first fluid (202) from the first fluid source (200) via the first fluid inlet port (106) to the first fluid intake duct (104) and along the first flow path (114) and thereby generate a first force (F) which maintains the first fluid pump (400) in engagement with the first fluid pump mount (128).

[0019] In the second mode of operation the first fluid pump (400) may be in a non-operational mode to permit it to be disengaged from the first fluid pump mount (128) and travel along the first pump guide path (122) away from the pumping position (126).

[0020] The first fluid pump mount (128) may comprise a pump abutment feature (124) which extends at least part of the way across the first fluid intake duct (104) to engage with the first fluid pump (400).

[0021] The pump access port (120) may be located above the first fluid pump mount (128).

[0022] The fluid treatment apparatus (100) may comprise a vortex generator apparatus (800).

[0023] The vortex generator apparatus (800) may comprise a fluid tank (802) defined by a first fluid tank sidewall (804). The vortex generator apparatus (800) may comprise a second fluid intake duct (806) in fluid communication with the first fluid inlet port (106) via the first fluid intake duct (104). The second fluid intake duct (806) may extend to a first curved flow channel (808) defined between a first sidewall segment (810) of the first fluid tank sidewall (804) and a second sidewall segment (812) of the first fluid tank sidewall (804).

[0024] The second fluid intake duct (806) may be provided substantially on a tangent to the first sidewall segment (810) of the first fluid tank sidewall (804) and aligned to deliver the first fluid (202) to an internal surface (814) of the first sidewall segment (810).

[0025] The second fluid intake duct (806) may be interfaced with an outer surface (816) of the fluid tank (802) to communicate the first fluid (202) along the outer surface (816). The fluid outlet port (110) is defined by the fluid tank (802).

[0026] The first fluid intake duct (104) and the second fluid intake duct (806) may extend at an angle to one another and are joined by a flow turning duct section (130) which is in flow communication with the first fluid intake duct (104) at a position between the pump access port (120) and the first fluid pump mount (128).

[0027] The first fluid intake duct (104) may comprise a first anchor (140) and a first suspension member (142). In the first mode of operation and/or second mode of operation the suspension member (142) may be coupled to the first anchor (140) and the first fluid pump (400) such that the suspension member (142) extends along the first fluid intake duct (104).

[0028] The first fluid intake duct (104) may comprise a first anchor (140) and a first suspension member (142). In the second mode of operation the suspension member (142) may be coupled to the first anchor (140) and the first fluid pump (400) such that the suspension member (142) extends along first fluid intake duct (104). In the first mode of operation the first suspension member (142) may be uncoupled from the first anchor (140) and uncoupled from the first fluid pump (400) and located outside of the first fluid intake duct (104), such that the first flow path (114) is unobstructed between the first fluid pump (400) and the pump access port (120).

[0029] The first anchor (140) may be provided proximate to the pump access port (120).

[0030] The first fluid pump mount (128) may comprise a first engagement feature (160) which is configured to engage with a second engagement feature (428) provided on the first fluid pump (400).

[0031] The first engagement feature (160) and second engagement feature (428) may be configured to prevent the first fluid pump (400) rotating relative to first fluid intake duct (104) about the longitudinal axis (112). The first engagement feature (160) and second engagement feature (428) may be configured to permit the first fluid pump (400) to move along the longitudinal axis (112) relative to first fluid intake duct (104).

[0032] The first fluid intake duct (104) may comprise an intake section (150) provided between the first fluid pump mount (128) and the first fluid inlet port (106), wherein the intake section (150) comprises an array of anti-swirl plates (152) which define a section of the first flow path (114).

[0033] The fluid treatment apparatus (100) may further comprise a fluid discharge port (500) provided between the first fluid inlet port (106) and the second fluid inlet port (108) along the first flow path (114).

[0034] The fluid treatment apparatus (100) may further comprise a flow control system (900). The flow control system may be operable to receive a parameter value from one or more sensors (902) provided in the first flow path (114), and to generate a pump control signal (S) in dependence of the parameter value, wherein the first fluid pump (400) is configured to receive, and operate in dependence of, the pump control signal (S).

[0035] One or more sensors (902) may be provided in the first flow path (114).

[0036] The one or more sensors (902) may include a dissolved oxygen sensor The one or more sensors (902) may include at least one sensor selected from a group comprising: a pressure sensor, a flow rate sensor, a flow velocity sensor, a pH sensor, an oxidation reduction potential sensor and a mixed liquor suspended solids sensor.

[0037] The control system may be configured such that when a dissolved oxygen value detected is equal to or lower than a low dissolved oxygen setpoint, the flow control system generates a pump control signal (S) configured to activate the first fluid pump (400).

[0038] The control system may be configured such that when the dissolved oxygen value detected is equal to or greater than a high dissolved oxygen setpoint, the flow control system generates a pump control signal (S) configured to deactivate the first fluid pump (400).

[0039] The flow control system may be operable to set a speed of the first fluid pump (400) in dependence of a dissolved oxygen value detected by the one or more sensors (902).

[0040] The fluid treatment apparatus (100) may comprise a third fluid intake duct (1104) which defines a third fluid inlet port (1106) for fluid communication with the first fluid source (200). The third fluid intake duct (1104) may have a second fluid pump mount (1128) which defines a pumping position (1126) in the third fluid intake duct (1104).

[0041] The third fluid intake duct (1104) may be fluidly connected to the vortex generator apparatus (800) via the second fluid intake duct (806).

[0042] The first fluid intake duct (104) and third fluid intake duct (1104) may be fluidly connected to the second fluid intake duct (806) via a flow control unit (860).

[0043] The flow control unit (860) may be operable to control flow in the first fluid intake duct (104) and the third fluid intake duct (1104) such that when the first fluid intake duct (104) is in fluid communication with the second fluid intake duct (806), the third fluid intake duct (1104) is fluidly isolated from the second fluid intake duct (806).

[0044] The flow control unit (860) may be operable to control flow in the first fluid intake duct (104) and the third fluid intake duct (1104) such that when the first fluid intake duct (104) is fluidly isolated from the second fluid intake duct (806), the third fluid intake duct (1104) is in fluid communication with the second fluid intake duct (806).

[0045] The flow control unit (860) may be operable to control flow in the first fluid intake duct (104) and the third fluid intake duct (1104) such that when the first fluid intake duct (104) is in fluid communication with the second fluid intake duct (806), the third fluid intake duct (1104) is in fluid communication with the second fluid intake duct (806).

[0046] The fluid treatment apparatus (100) may further comprise a third fluid intake duct (1104) which defines a third fluid inlet port (1106) for fluid communication with the first fluid source (200).

[0047] The third fluid intake duct (1104) may have a second fluid pump mount (1128) which defines a pumping position (1126) in the third fluid intake duct (1104).

[0048] The fluid treatment apparatus (100) may further comprise a vortex generator apparatus (800) which comprises a fluid tank (802) defined by a first fluid tank sidewall (804) and a second fluid tank sidewall (1804).

[0049] The fluid treatment apparatus (100) may further comprise a second fluid intake duct (806) in fluid communication with the first fluid inlet port (106) via the first fluid intake duct (104). The second fluid intake duct (806) may extend to a first curved flow channel (808) defined between a first sidewall segment (810) of the first fluid tank sidewall (804) and a second sidewall segment (812) of the second fluid tank sidewall (1804).

[0050] The second fluid intake duct (806) may be provided substantially on a tangent to the first sidewall segment (810) of the first fluid tank sidewall (804) and aligned to deliver the first fluid (202) to an internal surface (814) of the first sidewall segment (810).

[0051] The second fluid intake duct (806) may be interfaced with an outer surface (816) of the second fluid tank sidewall (1804) to communicate the first fluid (202) along the outer surface (816).

[0052] The vortex generator apparatus (800) may further comprise a fourth fluid intake duct (1806) in fluid communication with the third fluid inlet port (1106) via the third fluid intake duct (1104). The fourth fluid intake duct (1806) may extend to a second curved flow channel (1808) defined between a third sidewall segment (1810) of the second fluid tank sidewall (1804) and a fourth sidewall segment (1812) of the first fluid tank sidewall (804). The fourth fluid intake duct (1806) may be provided substantially on a tangent to the third sidewall segment (1810) of the second fluid tank sidewall (1804) and aligned to deliver the first fluid (202) to an internal surface (1814) of the third sidewall segment (1810).

[0053] The fourth fluid intake duct (1806) may be interfaced with an outer surface (1816) of the first fluid tank sidewall (804) to communicate the first fluid (202) along the outer surface (1816).

[0054] The fluid outlet port (110) may be defined by the fluid tank (802).

[0055] The first fluid intake duct (104) may be fluidly connected to the fluid tank (802) via a first flow control valve (840). The third fluid intake duct (1104) may be fluidly connected to the fluid tank (802) via a second flow control valve (842).

[0056] The fluid treatment apparatus (100) may comprise a valve control system (850) operable to control flow in the first fluid intake duct (104) and the third fluid intake duct (1104).

[0057] The fluid treatment apparatus (100) may comprise a valve control system (850) operable to control flow in the first fluid intake duct (104) and the third fluid intake duct (1104) such that when the first fluid intake duct (104) is in fluid communication with the fluid tank (802), the third fluid intake duct (1104) is fluidly isolated from the fluid tank (802).

[0058] The fluid treatment apparatus (100) may comprise a valve control system (850) operable to control flow in the first fluid intake duct (104) and the third fluid intake duct (1104) such that when the first fluid intake duct (104) is fluidly isolated from the fluid tank (802), the third fluid intake duct (1104) is in fluid communication with the fluid tank (802).

[0059] The fluid treatment apparatus (100) may comprise a valve control system (850) operable to control flow in the first fluid intake duct (104) and the third fluid intake duct (1104) such that when the first fluid intake duct (104) is in fluid communication with the fluid tank (802), the third fluid intake duct (1104) is in fluid communication with the fluid tank (802).

[0060] The fluid treatment apparatus (100) may comprise a fifth fluid intake duct (510) for fluid communication with a third fluid source (600). The fifth intake duct (510) may comprise a flow control valve (512) and/or a third fluid displacement pump (514).

[0061] There may be provided a fluid treatment system (700) comprising a fluid treatment apparatus (100) according to the present disclosure and a first fluid reservoir (702) of the first fluid (202), wherein the first fluid inlet port (106) and the fluid outlet port (110) of the fluid treatment apparatus (100) are in fluid communication with the first fluid (202) in the first fluid reservoir (702).

[0062] The fluid treatment apparatus (100) may further comprise a fluid outlet duct (820) arranged in flow communication with the fluid outlet port (110) and terminating in a fluid outlet duct exit (822). The fluid outlet duct exit (822) may be submerged in the first fluid (202).

[0063] There may be provided a flotation unit (2000) for supporting a fluid treatment apparatus (100) according to the present disclosure in a first fluid reservoir (702) containing a first fluid (202). The flotation unit (2000) may comprise a frame assembly (2100) configured to extend around the extent of the fluid treatment apparatus (100). The frame assembly (2100) may comprise a mount (2200) to support the fluid treatment apparatus (100). The frame assembly (2100) may comprise a plurality of floats (2300) coupled to a frame assembly (2100).

[0064] The frame assembly (2100) may comprise corners (2110). A float of the plurality of floats (2300) may be provided at each corner.

[0065] The plurality of floats (2300) may be spaced apart from each other such that, with a fluid treatment apparatus (100) mounted to the mount (2200), each of the floats (2300) are spaced apart from features of the fluid treatment apparatus (100).

[0066] There may be provided a fluid treatment apparatus (100) according to the present disclosure, comprising a flotation unit (2000) according to the present disclosure, wherein the flotation unit (2000) is configured to support the fluid treatment apparatus (100) in a first fluid reservoir (702) containing the first fluid (202).

[0067] There may be provided a fluid treatment apparatus (100) according to the present disclosure, comprising a flotation unit (2000) according to the present disclosure, wherein the flotation unit (2000) is configured to support the vortex generator apparatus (800) in a first fluid reservoir (702) containing the first fluid (202).

[0068] The fluid treatment apparatus (100) may be provided with a stabilising weight (2400) which extends vertically downwards from the fluid outlet port (110). The stabilising weight (2400) may be configured to maintain an orientation of the fluid treatment apparatus (100) with respect to the first fluid reservoir (702) when the fluid treatment apparatus (100) is in use.

[0069] The vortex generator apparatus (800) may be provided with a stabilising weight (2400) which extends vertically downwards from the fluid outlet port (110). The stabilising weight (2400) may be configured to maintain an orientation of the vortex generator apparatus (800) with respect to the first fluid reservoir (702) when the fluid treatment apparatus (100) is in use.

[0070] Hence there may be provided a fluid treatment apparatus with a configuration which enables its associated pump to operate at maximum efficiency while also having a configuration in which its associated pump is easily accessible and/or replaceable.

[0071] Brief Description of the Drawings

[0072] Examples of the present disclosure will now be described with reference to the accompanying drawings, in which: Figure 1 shows a section of a fluid treatment system according to the present disclosure which includes a first example of a fluid treatment apparatus according to the present disclosure; Figure 2 shows a plan (top) view of the first example of a fluid treatment apparatus according to the present disclosure; Figure 3 shows a sectional view of a first example of a vortex generator apparatus which forms part of the fluid treatment apparatus of the present disclosure; Figure 4 shows a first sectional view of a fluid intake duct which forms part of a fluid treatment apparatus according to the present disclosure; Figure 5 shows a second sectional view of a fluid intake duct which forms part of a fluid treatment apparatus according to the present disclosure; Figure 6 shows a plan (top) view of a second example of a fluid treatment apparatus

[0073] according to the present disclosure;

[0074] Figure 7 shows an end on view of the second example of a fluid treatment apparatus according to the present disclosure; Figure 8 shows a section of a fluid treatment system according to the present disclosure which includes the second example of a fluid treatment apparatus according to the present

[0075] disclosure;

[0076] Figure 9 shows a plan (top) view of a third example of a fluid treatment apparatus according to the present disclosure; Figure 10 shows a sectional plan view of the third example of a vortex generator apparatus as shown in figure 9; Figure 11 shows a fluid treatment system according to the present disclosure which includes a first variant of the fluid treatment apparatus according to the present disclosure; Figure 12 shows a fluid treatment system according to the present disclosure which includes a second variant of the fluid treatment apparatus according to the present disclosure; Figure 13 shows a fluid treatment system according to the present disclosure which includes a third variant of the fluid treatment apparatus according to the present disclosure; Figure 14 shows a fluid treatment system according to the present disclosure which includes a fourth variant of the fluid treatment apparatus according to the present disclosure; Figure 15 shows a fluid treatment system according to the present disclosure which includes a fifth variant of the fluid treatment apparatus according to the present disclosure; Figure 16 shows a fluid treatment system according to the present disclosure which includes a sixth variant of the fluid treatment apparatus according to the present disclosure; Figure 17 shows a fluid treatment system according to the present disclosure which includes a seventh variant of the fluid treatment apparatus according to the present disclosure; Figure 18 shows a plan (top) view of a fluid treatment apparatus and flotation unit according

[0077] to the present disclosure;

[0078] Figure 19 shows a side view of a fluid treatment apparatus and flotation unit according to the present disclosure; Figures 20 to 22 illustrate modes of operation of a fluid treatment system and fluid treatment apparatus according to the present disclosure; and Figure 23 illustrates a fluid treatment system according to the present disclosure.

[0079] Detailed Description

[0080] The present disclosure relates to a fluid treatment apparatus 100. The fluid treatment apparatus 100 is configured for mixing, aerating or conditioning a first fluid 202 for treatment purposes. The fluid treatment apparatus 100 may be located in a first fluid reservoir 702 of the first fluid 202. The present disclosure relates to a flotation unit 2000 for supporting a fluid treatment apparatus 100. The present disclosure relates to a fluid treatment system 700 comprising a fluid treatment apparatus 100 and a first fluid reservoir 702 of the first fluid 202. The present disclosure relates to a method of operation of the fluid treatment apparatus 100. The present disclosure relates to a method of operation of the fluid treatment system 700.

[0081] Figures 1, 8, 11 show a fluid treatment system 700 according to the present disclosure. The fluid treatment system 700 comprises a fluid treatment apparatus 100 and a first fluid reservoir 702 of the first fluid 202.

[0082] As shown in the figures, the fluid treatment apparatus 100 may comprise a housing 102.

[0083] The housing 102 defines a first flow path 114. The housing 102 may comprise a first fluid intake duct 104 which defines a first fluid inlet port 106 for fluid communication with a first fluid source 200. Hence when the fluid treatment apparatus 100 is located in a first fluid reservoir 100 which contains the first fluid 202, the first fluid reservoir 702 provides the first fluid source 200. The first fluid intake duct 104 may define a longitudinal axis 112. The longitudinal axis 112, and hence the first fluid intake duct 104, may extend vertically.

[0084] The first fluid intake duct 104 may comprise a pump access port 120. The pump access port 120 may be provided spaced apart from the first fluid inlet port 106 along the longitudinal axis 112 of the first fluid intake duct 104.

[0085] The first fluid intake duct 104 may comprise a first fluid pump mount 128. The first fluid pump mount 128 may define a pumping position 126 in the first fluid intake duct 104. The pumping position 126 (and hence pump mount 128) may be located between the first fluid inlet port 106 and the pump access port 120.

[0086] The first fluid pump mount 128 may comprise a pump abutment feature 124 (e.g. a shelf or rib) which extends at least part of the way across the first fluid intake duct 104 to engage with a first fluid pump 400 located in the first fluid intake duct 104.

[0087] The first fluid pump mount 128 may comprise a first engagement feature 160 which is configured to engage with a second engagement feature 428 provided on the first fluid pump 400.

[0088] The first engagement feature 160 and second engagement feature 428 may be configured to prevent the first fluid pump 400 rotating relative to the first fluid intake duct 104 about the longitudinal axis 112. The first engagement feature 160 and the second engagement feature 428 may be configured to permit (e.g. to enable) the first fluid pump 400 to move along the longitudinal axis 112 relative to the first fluid intake duct 104.

[0089] The first engagement feature 160 may be provided as a protrusion, or plurality of protrusions (e.g. fins or vanes). The or each first engagement feature 160 (e.g. protrusion) may extend radially inwards from the inner surface of the first fluid intake duct 104 and extend axially along the longitudinal axis 112 at least part of way along the first fluid intake duct 104. The second engagement feature 428 may be provided as a slot or a plurality of slots configured for receiving the or each protrusion. The or each second engagement feature 428 (e.g. slot) may extend radially inwards from the outer surface of the first fluid pump 400 and extend axially along the length of the first fluid pump 400 (e.g. aligned and/or parallel with the longitudinal axis 112) at least part of way along the first fluid pump 400. Alternatively, the protrusions may be provided on the first fluid pump 400 and the slots may be provided on the first fluid intake duct 104.

[0090] The first fluid intake duct 104 may comprise an intake section 150 provided between the first fluid pump mount 128 and the first fluid inlet port 106, wherein the intake section 150 comprises an array of anti-swirl plates 152 which define a section of the first flow path 114.

[0091] The array of anti-swirl plates 152 may be provided as fins or vanes. The array of anti-swirl plates 152 may extend radially inwards from the inner surface of the intake section 150 and extend axially along the longitudinal axis 112 at least part of way along the intake section 150. The array of anti-swirl plates 152 are configured to reduce fluid swirl. In some examples this may be advantageous, for example to prevent the flow entering the first fluid pump 400 swirling, and hence maintain the efficiency of the first fluid pump 400 (for example by reducing cavitation in the pump).

[0092] The first fluid intake duct 104 may define a first pump guide path 122 configured for a first fluid pump 400 to translate along between the first fluid pump mount 128 to the pump access port 120. The pump access port 120 may be configured to enable (i.e. permit) the passage of a first fluid pump 400 therethrough.

[0093] The pump access port 120 may be located on a top side of the fluid treatment apparatus 100. The pump access port 120 may be located in a region of the fluid treatment apparatus 100 which, in normal operational use, is at or above the surface of the first fluid 202 in the first fluid reservoir 702.

[0094] The first fluid inlet port 106 may be located on an underside of the fluid treatment apparatus 100. The first fluid inlet port 106 may be located in a region of the fluid treatment apparatus 100 which, in normal operational use, the first fluid inlet port 106 is below the surface of the first fluid 202 in the first fluid reservoir 702.

[0095] The first fluid pump mount 128 may be located on an underside of the fluid treatment apparatus 100. The first fluid pump mount 128 may be located in a region of the fluid treatment apparatus 100 which, in normal operational use, is below the surface of the first fluid 202 in the first fluid reservoir 702.

[0096] The first fluid pump mount 128 may be located such that, in normal operational use, when the first fluid pump 400 is mounted on/in the first fluid pump mount 128, the first fluid pump 400 is below the surface of the first fluid 202 in the first fluid reservoir 702. Hence, in normal operational use, when the first fluid pump 400 is located on/in the first fluid pump mount 128, the first fluid pump 400 is positioned such that the first fluid pump 400 is submerged in the first fluid 202 in the first fluid source 200.

[0097] The housing may further comprise a second fluid inlet port 108 for fluid communication with a second fluid source 300 of a second fluid 302.

[0098] The second fluid source 300 may be the local atmosphere/environment, drawing in gaseous air under the action of the first fluid 202, or a liquid held in a reservoir drawn into the fluid tank 802 by the action of the first fluid 202, or gas or liquid from a pressurised or pumped source delivered into the fluid/swirl tank 802 independent of the flow characteristics of the first fluid 202.

[0099] The second fluid source 300 may also comprise a supply of particles, such as powdered chemicals, which are drawn into the fluid tank alongside the second fluid.

[0100] The housing may further comprise a fluid outlet port 110 for fluid delivery to the first fluid source 200. The second fluid inlet port 108 may be located along the first flow path 114 between the first fluid inlet port 106 and the fluid outlet port 110.

[0101] The pump access port 120 may be located between the first fluid inlet port 106 and the second fluid inlet port 108 along the first flow path 114. The pump access port 120 may be located above the first fluid pump mount 128. The pump access port 120 may be located vertically above the first fluid pump mount 128.

[0102] In a fluid treatment system 700 according to the present disclosure, the first fluid inlet port 106 and the fluid outlet port 110 of the fluid treatment apparatus 100 are in fluid communication with the first fluid 202 in the first fluid reservoir 702.

[0103] The fluid treatment apparatus 100 may further comprise a first fluid pump 400. In a first mode of operation the first fluid pump 400 may be engaged with the first fluid pump mount 128 to thereby locate the first fluid pump 400 at the pumping position 126 within the first fluid intake duct 104 and in fluid communication with the first fluid source 200 via the first fluid inlet port 106.

[0104] As illustrated in figures 20, 21, 22, in a second mode of operation the first fluid pump 400 is operable to travel along the first pump guide path 122 from the pumping position 126 (in figure 20) to, and through, the pump access port 120 (in figure 22). The first fluid pump 400 and first fluid intake duct 104 are configured and sized to permit the first fluid pump 400 to travel along the first fluid intake duct 104. There may be provided a small clearance between the first fluid pump 400 and the internal surface of the first fluid intake duct 104.

[0105] As illustrated in figures 1 to 3, 6, 8 to 23, the fluid treatment apparatus 100 may further comprise a vortex generator apparatus 800.

[0106] As illustrated in figure 3, the vortex generator 800 may comprise a fluid tank 802 defined by a sidewall 804. The vortex generator 800 may comprise a second fluid intake duct 806 in fluid communication with the first fluid inlet port 106 via the first fluid intake duct 104.

[0107] As illustrated in figures 1 to 3, 6 to 9, 11 to 22, the first fluid intake duct 104 and the second fluid intake duct 806 may extend at an angle to one another. The first fluid intake duct 104 and the second fluid intake duct 806 may be joined by a flow turning duct section 130 which is in flow communication with the first fluid intake duct 104 at a position between the pump access port 120 and the first fluid pump mount 128. Hence, in examples where present, the flow turning duct section 130 defines a section of the first flow path 114.

[0108] Hence the flow turning duct section 130 is in fluid communication with the first fluid intake duct 104 and the pump access port 120. The first fluid intake duct 104 bifurcates, one branch leading to the pump access port 120 and the other branch leading to the flow turning duct section 130. In this way, fluid may pass along the first fluid intake duct 104 to the second fluid intake duct 806 via the flow turning duct section 130, and the first fluid pump 400 may pass along the first fluid intake duct 104 to the pump access port 120.

[0109] As illustrated in figure 1, in the first mode of operation the first fluid pump 400 may be operable to be in an operational mode to pump a first fluid 202 from the first fluid source 200 via the first fluid inlet port 106 to the first fluid intake duct 104 and along the first flow path 114 and thereby generate a first force F which maintains the first fluid pump 400 in engagement with the first fluid pump mount 128. By virtue of the direction of thrust created by the pumping action of the first fluid pump 400, the first force F is in a direction (e.g. downwards, as shown in the figures) which is opposite to the direction of flow along the first fluid intake duct 104 (e.g. upwards, as shown in the figures), which thus maintains the first fluid pump 400 in engagement with the first fluid pump mount 128.

[0110] In the second mode of operation the first fluid pump 400 may be in a non-operational mode. In this mode of operation, the weight of the first fluid pump 400 (which will also act downwards, as shown in the figures) will keep the first fluid pump 400 in engagement with the first fluid pump mount 128.

[0111] In one example, in the second mode of operation, it is only the weight of the first fluid pump 400 which keeps the first fluid pump 400 in engagement with the first fluid pump mount 128. That is to say, in this example, there are provided no other means (for example latches or catches) for maintaining the first fluid pump 400 in engagement with the first fluid pump mount 128.

[0112] Hence, in the second mode of operation (and as illustrated in figures 20 to 22), the first fluid pump 400 and first fluid pump mount 128 are configured so as to permit (i.e. enable) the first fluid pump 400 to be disengaged and lifted from the first fluid pump mount 128 (as shown in figure 20) and travel along the first pump guide path 122 away from the pumping position 126 (as shown in figure 21).

[0113] Hence (and as illustrated in figures 20 to 22), in the second mode of operation, the first fluid pump 400 and first fluid pump mount 128 are configured so as to permit the first fluid pump 400 to be disengaged and lifted from the first fluid pump mount 128 (as shown in figure 20) and travel along the first pump guide path 122 away from the pumping position 126 (as shown in figure 21), past the inlet to the flow turning duct section 130, and through the pump access port 120 (as shown in figures 22, 23).

[0114] The first fluid intake duct 104 may comprise a first anchor 140 and a first suspension member 142. The first suspension member 142 may be a flexible tether, for example a chain, cable or rope. The first suspension member 142 may be a rigid member, such as a rod or bar.

[0115] In an example of the present disclosure (and as shown in figure 20), in the first mode of operation and/or second mode of operation the suspension member 142 is coupled to the first anchor 140 and the first fluid pump 400 such that the suspension member 142 extends along the first fluid intake duct 104.

[0116] In another example of the present disclosure, in the second mode of operation the suspension member 142 may be coupled to the first anchor 140 and the first fluid pump 400 such that the suspension member 142 extends along first fluid intake duct 104. In the same example, in the first mode of operation the first suspension member 142 is uncoupled from the first anchor 140 and/or uncoupled from the first fluid pump 400, and located outside of (i.e. removed from) the first fluid intake duct 104 such that the first flow path 114 is unobstructed between the first fluid pump 400 and the pump access port 120.

[0117] The first anchor 140 may be provided proximate to the pump access port 120.

[0118] Hence, as illustrated in figures 20 to 23, in a second mode of operation the first fluid pump 400, the first suspension member 142 is pulled to draw the first fluid pump 400 along the first pump guide path 122 from the pumping position 126 to, and through, the pump access port 120. Once removed, the first fluid pump 400 may be worked on. The first fluid pump 400 may be re-installed (or a replacement first fluid pump 400 put in its place) by attaching the first suspension member 142 to the first fluid pump 400 and lowering the first fluid pump 400 into engagement with the first fluid pump mount 128.

[0119] As illustrated in figure 3, the second fluid intake duct 806 of the vortex generator 800 may extend to a first curved flow channel 808 defined between a first sidewall segment 810 of the first fluid tank sidewall 804 and a second sidewall segment 812 of the first fluid tank sidewall 804. The second fluid intake duct 806 may be provided substantially on a tangent to the first sidewall segment 810 of the first fluid tank sidewall 804 and aligned to deliver the first fluid 202 to an internal surface 814 of the first sidewall segment 810. The second fluid intake duct 806 may be interfaced with an outer surface 816 of the fluid tank 802 to communicate the first fluid 202 along the outer surface 816. The fluid outlet port 110 may be defined by the fluid tank 802. The second fluid intake duct 806 may comprise a divergent section 830. That is to say, the second fluid intake duct 806 may increase in flow area towards the fluid tank 802.

[0120] As illustrated in figures 1, 8 to 17, 19 to 22, the fluid treatment apparatus 100 may further comprise a fluid outlet duct 820 arranged in flow communication with the fluid outlet port 110 and terminating in a duct exit 822.

[0121] The fluid outlet port 110 may exhaust directly into the fluid outlet duct 820. The fluid outlet duct 820 may comprise a divergent section 824 such that the fluid outlet duct exit 822 has an internal cross-sectional area which is larger than the internal cross-sectional area of the fluid outlet port 110. The fluid outlet duct 820 may diverge (i.e. grow in internal cross-sectional area) from where it extends from the fluid outlet port 110. At the interface of the fluid outlet port 110 and the fluid outlet duct 820, the fluid outlet port 110 and the fluid outlet duct 820 may have the same internal cross-sectional area (i.e. the same flow area). Alternatively, at the interface of the fluid outlet port 110 and the fluid outlet duct 820, the fluid outlet port 110 may have a smaller internal cross-sectional area than the fluid outlet duct 820.

[0122] As shown in figures 1, 8, 11, 20 to 22 when the fluid treatment apparatus 100 is assembled in situ as part of the fluid treatment system 700, the fluid outlet duct exit 822 may be submerged in the first fluid 202. That is to say, when the vortex generator 800 is mounted in the first fluid reservoir 702 (i.e. when the fluid treatment apparatus 100 is located in the fluid reservoir 702 in the first fluid 202) the fluid outlet duct exit 822 is submerged in the first fluid 202.

[0123] The outlet duct exit 822 is submerged beneath the surface of the first fluid 202 in the first fluid reservoir 702 to deliver the mix of first fluid 202 and second fluid 302 to the first fluid reservoir 702. In examples in which the second fluid 302 is air, a vortex of liquid is formed with an air core extending there through, resulting in a discharge of aerated liquid from the outlet duct exit 822.

[0124] As illustrated in the figures, the second fluid inlet port 108, the fluid outlet port 110 and the duct exit 822 may be provided in series along a common axis 826. The common axis 826 may also be the fluid rotational axis 826 in the fluid tank 802 (i.e. the axis around which fluid in the fluid tank 802 rotates). The second fluid inlet port 108, the fluid outlet port 110 and the duct exit 822 may be concentric (i.e. arranged concentrically).

[0125] The second fluid inlet port 108 and the fluid outlet port 110 are arranged to be concentric. More particularly, the second fluid inlet port 108 and the fluid outlet port 110 are centred on the fluid rotational axis 826 at opposite ends of the fluid tank 802.

[0126] As illustrated in figure 3, the sidewall 804 of the fluid tank 802 may define a spiral centred on the common axis 826. Hence the internal surface 814 of the fluid tank 802 may define a spiral flow path centred on the common axis 826. The internal surface 814 of the fluid tank 802 may define a spiral flow path centred on the fluid outlet port 110. The sidewall 804 of the fluid tank 802 may define a spiral centred on the fluid outlet port 110.

[0127] The basic operation of the fluid treatment apparatus 100 of the present disclosure is described as follows. During operation, the first fluid 202, which is pumped by the first fluid pump 400, is supplied to the first fluid intake duct 806. The first fluid 202 (or "primary fluid"), which is to be treated or mixed, travels through the fluid intake duct 806 and is delivered to the fluid tank 802. In particular, the first fluid intake duct 806 is provided substantially on a tangent to the sidewall 804 of the fluid tank 802 and aligned to deliver the first fluid 202 to the internal surface 814 of the sidewall 804. Thus, the first fluid 202 is subjected to swirl and circulation about the fluid rotational axis 826, promoting the formation of a vortex. As first fluid 202 travels through the first fluid inlet port 106, the first fluid 202 is confined to the first curved flow channel 808 formed between the first sidewall segment 810 and the second sidewall segment 812 to aid the transition from the linear flow through the first fluid intake duct 806 and the vortex flow within the fluid tank 802. Accordingly, the first curved flow channel 808 guides flow that is injected into the fluid tank 802, and the first curved flow channel 808 separates the flow that is being injected into the fluid tank 802 from a vortex within the fluid tank 802.

[0128] The flow of first fluid 202 causes a pressure differential, as a result of which the second fluid 302 (or "secondary fluid") is drawn into the fluid tank 802. That is to say, the second fluid 302 is drawn in under the action of the first fluid 202. This causes the first fluid 202 and the second fluid 302 to cooperate to generate a vortex about the fluid rotational axis 826.

[0129] The flow comprises a vortex of the first fluid 202 swirling around a central core of the second fluid 302, which is a quasi-cylindrical region centred over the outlet port 110. The vortex is maintained as the first fluid 202 and the second fluid 302 exit the fluid tank 802 through the fluid outlet port 110, such that the vortex also extends through the fluid outlet duct 820 in the form of an annular jet. More particularly, the outlet duct 820 maintains the stability of the vortex and channels it to the first fluid reservoir 702.

[0130] Ultimately, the mix of fluids 202, 302 passes through the duct exit 822. In some examples the duct exit 822 is located beneath the surface of the first fluid reservoir 702. Such an arrangement enables mixing and, as the case may be, aeration. With the duct exit 822 located beneath the surface of the first fluid 202, there is no pure aerodynamic connection between the second fluid inlet port 108 and the underside of the vortex. In an example in which the second fluid is air, the addition of the second fluid 302 will result in the generation of bubbles in the first fluid 202.

[0131] In an alternative example, there is provided a first fluid connection between the vortex chamber and the receiving fluid reservoir 702. Thus, as the first fluid 202 travels from the fluid tank 802, the annular jet entrains second fluid 302, which is further improved by the plunging annular jet inside the outlet duct 820.

[0132] Where the second fluid 302 is buoyant when submerged in the first fluid 202, such as in the case of air (i.e. second fluid 302) and wastewater (i.e. first fluid 202), a bubble column is formed within the outlet duct 820. The bubble column contains bubbles of the second fluid 302 which remain in suspension within the outlet duct 820 for a prolonged period of time, neither escaping through the duct exit 822 nor the fluid outlet port 110, to further improve mixing and mass transfer.

[0133] As illustrated in figures 15, 16, one or more baffles 832, 864 may be provided on the sidewalls of the fluid outlet duct 820.

[0134] For example, as shown in figure 15, a partial baffle 832 may be provided at an outer edge of the fluid outlet duct 820. That is to say, a partial baffle 832 may extend from the outlet defined by the fluid outlet duct 820. The partial baffle 832 may extend away from the outlet defined by the outer edge of the fluid outlet duct 820, so that it (in use) would extend deeper into the first fluid 202 than the fluid outlet duct 820. The partial baffle 832 may extend vertically downwards away from the outlet defined by the outer edge of the fluid outlet duct 820. The partial baffle 832 may extend part, but not all of the way, around the circumference of the outlet defined by the outer edge of the fluid outlet duct 820. The partial baffle 832 may extend at least 25% but no more than 75% of the way around the circumference of the outlet defined by the outer edge of the fluid outlet duct 820. The partial baffle 832 may extend at least 25% but no more than 50% of the way around the circumference of the outlet defined by the outer edge of the fluid outlet duct 820. The partial baffle 832 acts to limit momentum of fluid exiting the fluid outlet duct 820 on the side of the outlet duct 820 on which the partial baffle 832 is present. This configuration promotes unidirectional mixing and flow in the reservoir 702 for applications that require it (for example in oxidation ditches).

[0135] In the example shown in figure 16, a series of slatted baffles 864 may be provided arranged concentrically with the fluid outlet duct 820. That is to say, a series of slatted baffles 864 may extend from the outlet defined by the fluid outlet duct 820. The series of slatted baffles 864 may extend away from the outlet defined by the outer edge of the fluid outlet duct 820, so that they (in use) would extend deeper into the first fluid 202 than the fluid outlet duct 820. The series of slatted baffles 864 may be aligned with (i.e. extend at the same angle relative to the vertical as) the wall which defines the fluid outlet duct 820. The series of slatted baffles 864 may extend all of the way around the circumference of the outlet defined by the outer edge of the fluid outlet duct 820. Hence the series of slatted baffles 864 may be provided in a frustoconical shape. The slatted baffles 864 may comprise a series of slats (e.g. panels) which are arranged relative to one another such that a flow path/route is provided between each of the slats. In this way, the momentum of fluid exiting the fluid outlet duct 820 is preserved for longer as it flows into the first fluid 202 of the first fluid reservoir 702, which increases mixing between the first fluid 202 and second fluid 302 and mixing of the combination of the first fluid 202 and the second fluid 302 exiting the fluid outlet duct 820 and the first fluid 202 of the first fluid reservoir 702.

[0136] As illustrated in figure 17, one or more curved baffles 866 may be provided in series with the fluid outlet duct 820. The curved baffles 866 may be fixed relative to the fluid treatment apparatus 100 and or the fluid reservoir 702 by any appropriate means. As illustrated in figure 17, the curved baffles are configured to guide the first fluid from the first outlet duct 820 to generate a flow in the first reservoir 702.

[0137] As illustrated in figures 11, 19, the fluid treatment apparatus 100 may comprise a fluid discharge port 500 provided between the first fluid inlet port 106 and the second fluid inlet port 108 along the first flow path 114. The first fluid inlet port 106 may be provided with a discharge valve 502. The discharge valve 502 may be provided in series with the fluid discharge port 500.

[0138] When required, and when the fluid apparatus 100 is in operation, fluid from the first reservoir 702 may be tapped off from the first flow path 114. For example, when the fluid apparatus 100 is in operation, the valve 502 is opened and fluid from the first fluid reservoir 702 may flow through the discharge port 500. This may be advantageous if it is needed to drain some of contents of the first reservoir 702, for example surplus activated sludge which has accumulated in the first fluid reservoir 702. In this way, the pump(s) in the intake duct(s) of the fluid treatment apparatus may be used to pump debris/sludge from the reservoir 702. This is advantageous over examples of the related art where a separate pump may be required to remove waste debris/sludge.

[0139] As illustrated in figures 11, 19, the fluid treatment apparatus 100 may further comprise a flow control system 900. The flow control system 900 may be operable to receive a parameter value from one or more sensors 902 and/or a user interface. The flow control system may be operable to generate a pump control signal S in dependence of the parameter value. The first fluid pump 400 is configured to receive, and operate in dependence of, the pump control signal S. As illustrated in figures 11 to 19, one or more sensors 902 may be provided to sense properties of the flow in the first flow path 114. The one or more sensors 902 may be provided (i.e. located) in first fluid intake duct 806 and/or the fluid tank 802.

[0140] The one or more sensors 902 may be selected from a group comprising: a pressure sensor, a flow rate sensor, a flow velocity sensor, a pH sensor, an oxidation reduction potential sensor, a dissolved oxygen sensor and a mixed liquor suspended solids sensor.

[0141] In an example, at least one of the sensors 902 may be a dissolved oxygen sensor. In this example, when a dissolved oxygen value detected is equal to or lower than a low dissolved oxygen setpoint the flow control system is operable to generate (i.e. generates) a pump control signal S configured to activate the first fluid pump 400. In the same example, when the dissolved oxygen value detected is equal to or greater than a high dissolved oxygen setpoint, the flow control system is operable to generate (i.e. generates) a pump control signal S configured to deactivate the first fluid pump 400.

[0142] The flow control system may be operable to set a speed of the first fluid pump 400 in dependence of a dissolved oxygen value detected by the one or more sensors 902.

[0143] As illustrated in the example of figures 6 to 8 and the example of figures 9, 10, the fluid treatment apparatus 100 may further comprise a third fluid intake duct 1104 which defines a third fluid inlet port 1106 for fluid communication with the first fluid source 200, the third fluid intake duct 1104 having a second fluid pump mount 1128 which defines a pumping position 1126 in the third fluid intake duct 1104.

[0144] In these examples, the fluid treatment apparatus 100 may further comprise a second fluid pump 1400, wherein in a first mode of operation the second fluid pump 1400 is engaged with the second fluid pump mount 1128 to thereby locate the second fluid pump 1400 at the pumping position 1126 within the third fluid intake duct 1104 and in fluid communication with the first fluid source 200 via the third fluid inlet port 1106.

[0145] In examples where a second fluid pump 1400 is present, in a second mode of operation the second fluid pump 1400 is operable to travel along a second pump guide path 1122 from the pumping position 1126 in the third fluid intake duct 1104 to, and through, a pump access port 1120 provided in the third fluid intake duct 1104. In the second mode of operation a second suspension member 1142 may be coupled to a second anchor 1140 and the second fluid pump 1400 such that the suspension member 1142 extends along the third fluid intake duct 1104.

[0146] Hence in a second mode of operation of the second fluid pump 1400, the second suspension member 1142 is pulled to draw the second fluid pump 1400 along the second pump guide path 1122 from the pumping position 1126 to, and through, the second pump access port 1120. Once removed, the second fluid pump 1400 may be worked on. The second fluid pump 1400 may be re-installed (or a replacement second fluid pump 1400 put in its place) by attaching the second suspension member 1142 to the second fluid pump 1400 and lowering the second fluid pump 1400 into engagement with the second fluid pump mount 1128.

[0147] In the examples of figures 6 to 8, the third fluid intake duct 1104 may be fluidly connected to the vortex generator apparatus 800 via the second fluid intake duct 806. In the same example, the first fluid intake duct 104 and third fluid intake duct 1104 may be fluidly connected to the second fluid intake duct 806 via a flow control unit 860. The flow control unit 860 may be operable to control flow in the first fluid intake duct 104 and the third fluid intake duct 1104. In one example (and as shown in figure 7) the flow control unit 860 may comprise a first flow control unit valve 870 provided in the flow path between the first fluid intake duct 104 and the second fluid intake duct 806, and a second flow control unit valve 880 provided in the flow path between the third fluid intake duct 1104 and the second fluid intake duct 806.

[0148] The flow control unit 860 may be operable to control flow in the first fluid intake duct 104 and the third fluid intake duct 1104 such that when the first fluid intake duct 104 is in fluid communication with the second fluid intake duct 806, the third fluid intake duct 1104 is fluidly isolated from the second fluid intake duct 806. In this scenario, and in examples where present, the first flow control unit valve 870 is open and the second flow control unit valve 880 is closed.

[0149] The flow control unit 860 may be operable to control flow in the first fluid intake duct 104 and the third fluid intake duct 1104 such that when the first fluid intake duct 104 is fluidly isolated from the second fluid intake duct 806, the third fluid intake duct 1104 is in fluid communication with the second fluid intake duct 806. In this scenario, and in examples where present, the first flow control unit valve 870 is closed and the second flow control unit valve 880 is open.

[0150] The flow control unit 860 may be operable to control flow in the first fluid intake duct 104 and the third fluid intake duct 1104 such that when the first fluid intake duct 104 is in fluid communication with the second fluid intake duct 806, the third fluid intake duct 1104 is in fluid communication with the second fluid intake duct 806. In this scenario, and in examples where present, the first flow control unit valve 870 is open and the second flow control unit valve 880 is open.

[0151] The flow control unit 860 may be operable to control flow in the first fluid intake duct 104 and the third fluid intake duct 1104 such that when the first fluid intake duct 104 is fluidly isolated from the second fluid intake duct 806, the third fluid intake duct 1104 is fluidly isolated from the second fluid intake duct 806. In this scenario, and in examples where present, the first flow control unit valve 870 is closed and the second flow control unit valve 880 is closed.

[0152] As illustrated in the example of figures 9, 10 the fluid treatment apparatus 100 may comprise a vortex generator apparatus 800 which comprises a fluid tank 802 defined by a first fluid tank sidewall 804 and a second fluid tank sidewall 1804. As shown in this example, the fluid treatment apparatus 100 may comprise a second fluid intake duct 806 in fluid communication with the first fluid inlet port 106 via the first fluid intake duct 104. The second fluid intake duct 806 may -20 -extend to a first curved flow channel 808 defined between a first sidewall segment 810 of the first fluid tank sidewall 804 and a second sidewall segment 812 of the second fluid tank sidewall 1804. The second fluid intake duct 806 may be provided substantially on a tangent to the first sidewall segment 810 of the first fluid tank sidewall 804 and aligned to deliver the first fluid 202 to an internal surface 814 of the first sidewall segment 810. The second fluid intake duct 806 may be interfaced with an outer surface 816 of the second fluid tank sidewall 1804 to communicate the first fluid 202 along the outer surface 816.

[0153] In the example of figures 9, 10 the vortex generator apparatus 800 may comprise a fourth fluid intake duct 1806 in fluid communication with the third fluid inlet port 1106 via the third fluid intake duct 1104. The fourth fluid intake duct 1806 may extend to a second curved flow channel 1808 defined between a third sidewall segment 1810 of the second fluid tank sidewall 1804 and a fourth sidewall segment 1812 of the first fluid tank sidewall 804. The fourth fluid intake duct 1806 may be provided substantially on a tangent to the third sidewall segment 1810 of the second fluid tank sidewall 1804 and aligned to deliver the first fluid 202 to an internal surface 1814 of the third sidewall segment 1810. The fourth fluid intake duct 1806 may be interfaced with an outer surface 1816 of the first fluid tank sidewall 804 to communicate the first fluid 202 along the outer surface 1816.

[0154] The fluid outlet port 110 may be defined by the fluid tank 802.

[0155] In the example of figures 9, 10, the first fluid intake duct 104 may be fluidly connected to the fluid tank 802 via a first flow control valve 840. The third fluid intake duct 1104 may be fluidly connected to the fluid tank 802 via a second flow control valve 842. The fluid treatment apparatus 100 may further comprise a valve control system 850 operable to control flow in the first fluid intake duct 104 and the third fluid intake duct 1104.

[0156] The valve control system 850 may be operable (i.e. configured) such that when the first flow control valve 840 is open such that the first fluid intake duct 104 is in fluid communication with the fluid tank 802, the second flow control valve 842 is closed such that third fluid intake duct 1104 is fluidly isolated from the fluid tank 802.

[0157] The valve control system 850 may be operable (i.e. configured) such that when the first flow control valve 840 is closed such that the first fluid intake duct 104 is fluidly isolated from the fluid tank 802, the second flow control valve 842 is open such that the third fluid intake duct 1104 is in fluid communication with the fluid tank 802.

[0158] The valve control system 850 may be operable (i.e. configured) such that when the first fluid intake duct 104 is in fluid communication with the fluid tank 802, the third fluid intake duct 1104 is in fluid communication with the fluid tank 802. In this scenario the first flow control valve 840 and the second flow control valve 842 are open. -21 -

[0159] In the examples of figures 6 to 8 and figures 9, 10, one or more sensors 902 may be provided within the fluid treatment apparatus 900 to provide a parameter value to a flow control system 900 of the fluid treatment apparatus 100. The flow control system 900 may be configured to determine the presence or absence of a fault in the operation of the first fluid pump 400 and/or a fault in the operation of the second fluid pump 1400 based on the parameter value.

[0160] Upon determination of a fault in the operation of the first fluid pump 1400, the flow control system is operable to provide a first pump control signal to the first fluid pump 400, such that the speed of the first fluid pump 400 is decreased (for example to zero rpm) and is operable to provide a second pump control signal to the second fluid pump 1400, such that the speed of the second fluid pump 1400 is increased.

[0161] Upon determination of a fault in the operation of the second fluid pump 1400, the flow control system is operable to provide a second pump control signal to the second fluid pump 1400, such that the speed of the second fluid pump 1400 is decreased (for example to zero rpm) and is operable to provide a first pump control signal to the first fluid pump 400, such that the speed of the first fluid pump 400 is increased.

[0162] In the examples of figures 6 to 8 and figures 9, 10, it may be required to shut down either one of the first fluid pump 400 or second fluid pump 1400, for example for maintenance. This may be done automatically or in response to an input command from a user.

[0163] Upon receipt of a shutdown signal for the first fluid pump 400, the flow control system is operable to provide a first pump control signal to the first fluid pump 400, such that the speed of the first fluid pump 400 is decreased (for example to zero rpm) and provides a second pump control signal to the second fluid pump 1400, such that the speed of the second fluid pump 1400 is increased.

[0164] Upon receipt of a shutdown signal for the second fluid pump 1400, the flow control system is operable to provide a second pump control signal to the second fluid pump 1400, such that the speed of the second fluid pump 1400 is decreased (for example to zero rpm) and provides a first pump control signal to the first fluid pump 400, such that the speed of the first fluid pump 400 is increased.

[0165] In examples where a first fluid pump 400 and a second fluid pump 1400 are provided, they may be operated such that one is operating at full capacity while the other is non-operational.

[0166] Alternatively they may be operated such that one is operating at partial capacity while the other is operating at partial capacity (hence together they are pumping the same amount of fluid as if one of the pumps was operating at full capacity). Hence the provision of a second fluid pump 1400 provides a back up, a fluid flow boost and alternative to the first fluid pump 400.

[0167] As illustrated in figures 12 to 14, the fluid treatment apparatus 100 may further comprise a fifth fluid intake duct 510 for fluid communication with a third fluid source 600 of a third fluid 302.

[0168] -22 -The third fluid source 600 may be a source of oxygen. For example, the third fluid source 600 may be a source of oxygen of higher percentage than available from ambient air.

[0169] The fifth intake duct 510 may comprise a flow control valve 512 for controlling the flow of third fluid 302 into the first flow path 114.

[0170] The first fluid 202, second fluid 302 and third fluid 602 may be different to one another.

[0171] The first fluid 202 may be wastewater, that is to say, water with solid pollutant present. The second fluid 302 may be air. The third fluid may be oxygen.

[0172] The fifth intake duct 510 may be in flow communication with the first flow path 114 via a fifth intake port 516 in the housing 102. The fifth intake port 516 may be located proximate to the second fluid inlet port 108 such that the third fluid 602 is delivered to the first flow path 114 in the same location as the second fluid 302.

[0173] As illustrated in figures 13,14, a third fluid displacement pump 514 (for example a fan fluid compressor) may be provided to deliver the third fluid through the fifth intake duct 510 to the first flow path 114 via the fifth intake port 516.

[0174] As illustrated in figure 23, the fluid treatment apparatus 100may be supported on a support structure 3000 above the fluid reservoir 702.

[0175] As illustrated in figures 18,19, there may be provided a flotation unit 2000 for supporting the fluid treatment apparatus 100 according to the present disclosure in a first fluid reservoir 702 containing a first fluid 202. The flotation unit 2000 may be provided as a separate structure to the fluid treatment apparatus 100. For example, the flotation unit 2000 may be constructed independently of the fluid treatment apparatus 100 with the fluid treatment apparatus 100 being coupled to the flotation unit 2000.

[0176] The fluid treatment apparatus 100 according to the present disclosure may comprise a flotation unit 2000, wherein the flotation unit 2000 is configured to support the fluid treatment apparatus 100 in a first fluid reservoir 702 containing the first fluid 202.

[0177] The fluid treatment apparatus 100 according to the present disclosure may comprise a flotation unit 2000, wherein (in examples including a vortex generator apparatus 800) the flotation unit 2000 is configured to support the vortex generator apparatus 800 in a first fluid reservoir 702 containing the first fluid 202.

[0178] The flotation unit 2000 may be provided as part of the fluid treatment apparatus 100. For example, the flotation unit 2000 may be integral with the fluid treatment apparatus 100.

[0179] As illustrated in figures 18,19, the flotation unit 2000 may comprise a frame assembly 2100 configured to extend around the extent of the fluid treatment apparatus 100.

[0180] -23 -The frame assembly 2100 may comprise a plurality of frame members 2120. Two frame members 2120 may be joined at one end (i.e. a corner 2110) and each extend from the join along a different side of the fluid treatment apparatus 100, their opposite ends being joined by a third frame member 2120 (to hence form two more corners 2110), the end frame member extending along one end of the fluid treatment apparatus 100. Hence (as shown in figure 18, 19, when viewed from above) the frame assembly 2120 may be triangular.

[0181] The frame assembly 2100 may comprise a mount 2200 to support the fluid treatment apparatus 100. The mount 2200 may extend between, and hence join, each of the side frame members 2120 and end member 2120.

[0182] The vortex generator apparatus 800 section of the fluid treatment apparatus 100 may be located on the mount 2200. Hence the fluid treatment apparatus 100 may be surrounded by the frame assembly 2100. The first fluid intake dud 104 may be located in a corner formed by the join between the two side frame members 2120.

[0183] The flotation unit 2000 may comprise a plurality of floats 2300 coupled to the frame assembly 2100.

[0184] A float 2300 of the plurality of floats 2300 may be provided at each corner 2100 of the frame assembly. Hence the plurality of floats 2300 may be spaced apart from each other such that, with a fluid treatment apparatus 100 mounted to the mount 2200, each of the floats 2300 are spaced apart from features of the fluid treatment apparatus 100.

[0185] As illustrated in figure 19, the fluid treatment apparatus 100 may be provided with a stabilising weight 2400 which extends vertically downwards from the fluid outlet port 110. In examples including a vortex generator apparatus 800, and as shown in figure 19, the vortex generator apparatus 800 may be provided with a stabilising weight 2400 which extends vertically downwards from the fluid outlet port 110.

[0186] The stabilising weight 2400 may be configured to maintain an orientation of the fluid treatment apparatus 100 with respect to the first fluid reservoir 702 when the fluid treatment apparatus 100 is in use. In examples including a vortex generator apparatus 800, the stabilising weight 2400 may be configured to maintain an orientation of the vortex generator apparatus 800 with respect to the first fluid reservoir 702 when the fluid treatment apparatus 100 is in use. The stabilising weight 2400 is provided, configured and located as a counterbalance system designed such the fluid treatment apparatus 100 has a low centre of gravity. Additionally, the stabilising weight 2400, being provided spaced apart from the pump 400, provides a force to counterbalance the force of the pump 400 when the pump is operation. Hence the stabilising weight 2400 may be provided in examples where needed so that the vortex apparatus 800 is level when the pump is operating.

[0187] -24 -The frame assembly 2100 may be tethered to one or more anchor point (for example in or around the fluid reservoir 702) such that it is free to float on the surface of the fluid in the fluid reservoir 702 (and hence moveable in a vertical direction) but fixed laterally.

[0188] Hence there may be provided a fluid treatment apparatus with a configuration which enables its associated pump to operate at maximum efficiency while also having a configuration in which its associated pump is easily accessible and/or replaceable.

[0189] The provision of a fluid intake duct 104, 1104 with a pump access port 120, 1120 the fluid pump mount 128, 1128, the first pump guide path 122, 1122 defined by the fluid intake duct 1104 for the fluid pump 400, 1400 to translate along between the fluid pump mount 128, 1128 to the pump access port 120, 1120 enables the pump mounted therein to be located in position in the fluid intake duct 104, 1104 so it may pump efficiently. The configuration also allows for the fluid pump 400, 1400 to be removed from the mount position and removed from the duct so it may be replaced and/or worked on in a convenient location.

[0190] Hence the fluid pump 400, 1400 may be submerged in the first fluid in the first fluid source 200 when the fluid treatment apparatus 100 is in use, and easily taken out of the fluid and out of the first fluid intake duct 104 as required.

[0191] The provision of a flotation unit 2000 to support the fluid treatment apparatus 100 is advantageous as it allows the fluid treatment apparatus 100 to float relative to the surface of the fluid being treated, and hence maintains the fluid inlet port 106, 1106 of the fluid intake duct 104 at a desired depth below the surface of the fluid, thereby ensuring that fluid is processed consistently regardless of the level of the fluid in the first fluid reservoir 702.

[0192] The provision of a flotation unit 2000 to support the fluid treatment apparatus 100 also may facilitate a fast installation of a fluid treatment apparatus 100 in a fluid reservoir 702, since the provision of a flotation unit 2000 means that no further structure is required to support the fluid treatment apparatus 100 on the first fluid 202.

[0193] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0194] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0195] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar -25 -purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0196] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

1. -26 -CLAIMS1. A fluid treatment apparatus (100) comprising: a housing (102) which defines a first flow path (114), the housing (102) comprising a first fluid intake duct (104) which defines a first fluid inlet pod (106) for fluid communication with a first fluid source (200), wherein the first fluid intake duct (104) defines a longitudinal axis (112); the first fluid intake duct (104) comprising: a pump access port (120), the pump access port (120) being provided spaced apart from the first fluid inlet port (106) along the longitudinal axis (112) of the first fluid intake duct (104), a first fluid pump mount (128) which defines a pumping position (126) in the first fluid intake duct (104) between the first fluid inlet port (106) and the pump access port (120); wherein the first fluid intake duct (104) defines a first pump guide path (122) configured for a first fluid pump (400) to translate along between the first fluid pump mount (128) and the pump access port (120); and the pump access port (120) being configured to enable the passage of a first fluid pump (400) therethrough.

2. A fluid treatment apparatus (100) as claimed in claim 1 wherein the housing further comprises: a second fluid inlet port (108) for fluid communication with a second fluid source (300); a fluid outlet port (110) for fluid delivery to the first fluid source (200); the second fluid inlet port (108) being located along the first flow path (114) between the first fluid inlet port (106) and the fluid outlet port (110).

3. A fluid treatment apparatus (100) as claimed in claim 1 and claim 2 further comprising a first fluid pump (400), wherein: in a first mode of operation the first fluid pump (400) is engaged with the first fluid pump mount (128) to thereby locate the first fluid pump (400) at the pumping position (126) within the first fluid intake duct (104); and -27 -in a second mode of operation the first fluid pump (400) is operable to travel along the first pump guide path (122) from the pumping position (126) to, and through, the pump access port (120).

4. A fluid treatment apparatus (100) as claimed in claim 3 wherein in the first mode of operation the first fluid pump (400) is operable to be in an operational mode to pump a first fluid (202) from the first fluid source (200) via the first fluid inlet port (106) to the first fluid intake duct (104) and along the first flow path (114) and thereby generate a first force (F) which maintains the first fluid pump (400) in engagement with the first fluid pump mount (128).

5. A fluid treatment apparatus (100) as claimed in claim 3 or claim 4 wherein in the second mode of operation the first fluid pump (400) is in a non-operational mode to permit it to be disengaged from the first fluid pump mount (128) and travel along the first pump guide path (122) away from the pumping position (126).

6. A fluid treatment apparatus (100) as claimed in any one of claims 1 to 5 wherein the first fluid pump mount (128) comprises a pump abutment feature (124) which extends at least part of the way across the first fluid intake duct (104) to engage with the first fluid pump (400).

7. A fluid treatment apparatus (100) as claimed in any one of claims 1 to 6 wherein the pump access port (120) is located above the first fluid pump mount (128).

8. A fluid treatment apparatus (100) as claimed in claim 3 or any one of claims 4 to 7 when dependent on claim 3 wherein the first fluid intake duct (104) comprises a first anchor (140) and a first suspension member (142); and in the first mode of operation and/or second mode of operation the suspension member (142) is coupled to the first anchor (140) and the first fluid pump (400) such that the suspension member (142) extends along the first fluid intake duct (104).

9. A fluid treatment apparatus (100) as claimed in claim 3 or any one of claims 4 to 7 when dependent on claim 3 wherein the first fluid intake duct (104) comprises a first anchor (140) and a first suspension member (142); -28 -in the second mode of operation the suspension member (142) is coupled to the first anchor (140) and the first fluid pump (400) such that the suspension member (142) extends along first fluid intake duct (104); and in the first mode of operation the first suspension member (142) is uncoupled from the first anchor (140) and uncoupled from the first fluid pump (400), and located outside of the first fluid intake duct (104) such that the first flow path (114) is unobstructed between the first fluid pump (400) and the pump access port (120).

10. A fluid treatment apparatus (100) as claimed in claim 8 or claim 9 wherein the first anchor (140) is provided proximate to the pump access port (120).

11. A fluid treatment apparatus (100) as claimed in any one of claims 1 to 10 wherein the first fluid pump mount (128) comprises a first engagement feature (160) which is configured to engage with a second engagement feature (428) provided on the first fluid pump (400), the first engagement feature (160) and second engagement feature (428) configured to: prevent the first fluid pump (400) rotating relative to first fluid intake duct (104) about the longitudinal axis (112), and permit the first fluid pump (400) to move along the longitudinal axis (112) relative to first fluid intake duct (104).

12. A fluid treatment apparatus (100) as claimed in any one of claims 1 to 11 wherein the first fluid intake duct (104) comprises an intake section (150) provided between the first fluid pump mount (128) and the first fluid inlet port (106), wherein the intake section (150) comprises an array of anti-swirl plates (152) which define a section of the first flow path (114).

13. A fluid treatment apparatus (100) as claimed in any one of claims 1 to 12 further comprising a fluid discharge port (500) provided between the first fluid inlet port (106) and the second fluid inlet port (108) along the first flow path (114).

14. A fluid treatment apparatus (100) as claimed in any one of claims 3 to 13 wherein the fluid treatment apparatus (100) further comprises a flow control system (900), the flow control system operable to receive a parameter value from one or more sensors (902) provided the first flow path (114), and to generate a pump control signal (S) in -29 -dependence of the parameter value. wherein the first fluid pump (400) is configured to receive, and operate in dependence of, the pump control signal (S); wherein the one or more sensors (902) include a dissolved oxygen sensor and at least one further sensor selected from a group comprising: a pressure sensor, a flow rate sensor, a flow velocity sensor, a pH sensor, an oxidation reduction potential sensor and a mixed liquor suspended solids sensor; wherein when a dissolved oxygen value detected is equal to or lower than a low dissolved oxygen setpoint the flow control system generates a pump control signal (S) configured to activate the first fluid pump (400); and when the dissolved oxygen value detected is equal to or greater than a high dissolved oxygen setpoint, the flow control system generates a pump control signal (S) configured to deactivate the first fluid pump (400).

15. A fluid treatment apparatus (100) as claimed in claim 14 wherein the flow control system is operable to set a speed of the first fluid pump (400) in dependence of a dissolved oxygen value detected by the one or more sensors (902).

16. A fluid treatment apparatus (100) as claimed in any one of claims 1 to 15 further comprising a vortex generator apparatus (800) which comprises: a fluid tank (802) defined by a first fluid tank sidewall (804); a second fluid intake duct (806) in fluid communication with the first fluid inlet port (106) via the first fluid intake duct (104); and the second fluid intake duct (806) extending to a first curved flow channel (808) defined between a first sidewall segment (810) of the first fluid tank sidewall (804) and a second sidewall segment (812) of the first fluid tank sidewall (804); and the second fluid intake duct (806) is provided substantially on a tangent to the first sidewall segment (810) of the first fluid tank sidewall (804) and aligned to deliver the first fluid (202) to an internal surface (814) of the first sidewall segment (810); wherein the second fluid intake duct (806) is interfaced with an outer surface (816) of the fluid tank (802) to communicate the first fluid (202) along the outer surface (816); and the fluid outlet port (110) is defined by the fluid tank (802).

17. A fluid treatment apparatus (100) as claimed in claim 16 wherein the first fluid intake duct (104) and the second fluid intake duct (806) extend at an angle to one another and -30 -are joined by a flow turning duct section (130) which is in flow communication with the first fluid intake duct (104) at a position between the pump access port (120) and the first fluid pump mount (128).

18. A fluid treatment apparatus (100) as claimed in claim 16 or claim 17 further comprising a third fluid intake duct (1104) which defines a third fluid inlet port (1106) for fluid communication with the first fluid source (200), the third fluid intake duct (1104) having a second fluid pump mount (1128) which defines a pumping position (1126) in the third fluid intake duct (1104); wherein the third fluid intake duct (1104) is fluidly connected to the vortex generator apparatus (800) via the second fluid intake duct (806).

19. A fluid treatment apparatus (100) as claimed in claim 18 wherein the first fluid intake duct (104) and third fluid intake duct (1104) are fluidly connected to the second fluid intake duct (806) via a flow control unit (860).

20. A fluid treatment apparatus (100) as claimed in claim 19 wherein the flow control unit (860) is operable to control flow in the first fluid intake duct (104) and the third fluid intake duct (1104) such that: when the first fluid intake duct (104) is in fluid communication with the second fluid intake duct (806), the third fluid intake duct (1104) is fluidly isolated from the second fluid intake duct (806); when the first fluid intake duct (104) is fluidly isolated from the second fluid intake duct (806), the third fluid intake duct (1104) is in fluid communication with the second fluid intake duct (806); and/or when the first fluid intake duct (104) is in fluid communication with the second fluid intake duct (806), the third fluid intake duct (1104) is in fluid communication with the second fluid intake duct (806).

21. A fluid treatment apparatus (100) as claimed in any one of claims 1 to 15 further comprising: a third fluid intake duct (1104) which defines a third fluid inlet port (1106) for fluid communication with the first fluid source (200), the third fluid intake duct (1104) having a -31 -second fluid pump mount (1128) which defines a pumping position (1126) in the third fluid intake duct (1104); and a vortex generator apparatus (800) which comprises: a fluid tank (802) defined by a first fluid tank sidewall (804) and a second fluid tank sidewall (1804); a second fluid intake duct (806) in fluid communication with the first fluid inlet port (106) via the first fluid intake duct (104); and the second fluid intake duct (806) extending to a first curved flow channel (808) defined between a first sidewall segment (810) of the first fluid tank sidewall (804) and a second sidewall segment (812) of the second fluid tank sidewall (1804) ; and the second fluid intake duct (806) is provided substantially on a tangent to the first sidewall segment (810) of the first fluid tank sidewall (804) and aligned to deliver the first fluid (202) to an internal surface (814) of the first sidewall segment (810); and the second fluid intake duct (806) is interfaced with an outer surface (816) of the second fluid tank sidewall (1804) to communicate the first fluid (202) along the outer surface (816); and the vortex generator apparatus (800) further comprises: a fourth fluid intake duct (1806) in fluid communication with the third fluid inlet port (1106) via the third fluid intake duct (1104); the fourth fluid intake duct (1806) extending to a second curved flow channel (1808) defined between a third sidewall segment (1810) of the second fluid tank sidewall (1804) and a fourth sidewall segment (1812) of the first fluid tank sidewall (804); and the fourth fluid intake duct (1806) is provided substantially on a tangent to the third sidewall segment (1810) of the second fluid tank sidewall (1804) and aligned to deliver the first fluid (202) to an internal surface (1814) of the third sidewall segment (1810); and the fourth fluid intake duct (1806) is interfaced with an outer surface (1816) of the first fluid tank sidewall (804) to communicate the first fluid (202) along the outer surface (1816); and the fluid outlet port (110) is defined by the fluid tank (802).

22. -32 - 22. A fluid treatment apparatus (100) as claimed in claim 21 wherein: the first fluid intake duct (104) is fluidly connected to the fluid tank (802) via a first flow control valve (840); and the third fluid intake duct (1104) is fluidly connected to the fluid tank (802) via a second flow control valve (842); and the fluid treatment apparatus (100) further comprises a valve control system (850) operable to control flow in the first fluid intake duct (104) and the third fluid intake duct (1104) such that: when the first fluid intake duct (104) is in fluid communication with the fluid tank (802), the third fluid intake duct (1104) is fluidly isolated from the fluid tank (802); when the first fluid intake duct (104) is fluidly isolated from the fluid tank (802), the third fluid intake duct (1104) is in fluid communication with the fluid tank (802); and/or when the first fluid intake duct (104) is in fluid communication with the fluid tank (802), the third fluid intake duct (1104) is in fluid communication with the fluid tank (802).

23. A fluid treatment apparatus (100) as claimed in any one of claims 1 to 22 further comprising a fifth fluid intake duct (510) for fluid communication with a third fluid source (600), the fifth intake duct (510) comprising a flow control valve (512) and/or a third fluid displacement pump (514).

24. A fluid treatment system (700) comprising a fluid treatment apparatus (100) as claimed in any one of claims 1 to 23 and a first fluid reservoir (702) of the first fluid (202), wherein the first fluid inlet port (106) and the fluid outlet port (110) of the fluid treatment apparatus (100) are in fluid communication with the first fluid (202) in the first fluid reservoir (702).

25. A fluid treatment system (700) as claimed in claim 24 when dependent on claim 2 wherein the fluid treatment apparatus (100) further comprises a fluid outlet duct (820) arranged in flow communication with the fluid outlet port (110) and terminating in a fluid outlet duct exit (822), wherein the fluid outlet duct exit (822) is submerged in the first fluid (202).

26. -33 - 26. A flotation unit (2000) for supporting a fluid treatment apparatus (100) as claimed in any of claims 1 to 23 in a first fluid reservoir (702) containing a first fluid (202), the flotation unit (2000) comprising: a frame assembly (2100) configured to extend around the extent of the fluid treatment apparatus (100); the frame assembly (2100) comprising a mount (2200) to support the fluid treatment apparatus (100); and a plurality of floats (2300) coupled to a frame assembly (2100).

27. The flotation unit (2000) as claimed in claim 26 wherein the frame assembly (2100) comprises corners (2110), and a float of the plurality of floats (2300) is provided at each corner.

28. The flotation unit (2000) as claimed in claim 26 or claim 27 wherein the plurality of floats (2300) are spaced apart from each other such that, with a fluid treatment apparatus (100) mounted to the mount (2200), each of the floats (2300) are spaced apart from features of the fluid treatment apparatus (100).

29. A fluid treatment apparatus (100) as claimed in any one of claims 1 to 23 comprising a flotation unit (2000) of any one of claims 26 to 28, wherein the flotation unit (2000) is configured to support the fluid treatment apparatus (100) in a first fluid reservoir (702) containing the first fluid (202).

30. A fluid treatment apparatus (100) of claim 29 when dependent on claim 2 wherein the fluid treatment apparatus (100) is provided with a stabilising weight (2400) which extends vertically downwards from the fluid outlet port (110), the stabilising weight (2400) is configured to maintain an orientation of the fluid treatment apparatus (100) with respect to the first fluid reservoir (702) when the fluid treatment apparatus (100) is in use.