GB2590304A

GB2590304A - Water treatment apparatus and method

Info

Publication number: GB2590304A
Application number: GB2101603.5A
Authority: GB
Inventors: Lee Ashwell Sean
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-08-30
Filing date: 2019-08-30
Publication date: 2021-06-23
Also published as: GB202101603D0

Abstract

A water treatment apparatus comprises a sediment settling system (100, Fig. 1) having a first water inlet (112, Fig. 1) arranged to receive water comprising sediment, a water outlet (126, Fig. 1) arranged to outlet the water, and an aeration member (134, Fig. 3) positioned beneath the water outlet and arranged to provide a bubble curtain across the water outlet. The apparatus also comprises a flocculation system 200 having a second water inlet 202 arranged to receive water from the water outlet of the sediment settling system, an effluent outlet 246 arranged to outlet an effluent liquid, a flocculating agent dosing device 204 arranged to dose the water with a flocculating agent, and a dispersing member 206 downstream of the dosing device for dispersing the flocculating agent within the water. Suitably, the dispersing member is an ultrasonic transducer, which can sonicate the flocculating agent at an ultrasonic frequency of between 40 kHz to 200 kHz. The flocculating agent can comprise an acid, e.g. acetic acid, and a base, e.g. sodium bicarbonate. The present invention aims to provide a modular water treatment solution which is easy to maintain and which may be transportable.

Description

WATER TREATMENT APPARATUS AND METHOD

Field of the Invention

The present invention relates to a water treatment apparatus and method.

Background to the Invention

Water treatment in the context of the present application is the process of improving the quality of water.

A desired water quality may vary depending on use, for example drinking water, non-potable domestic use, and industrial water supply. Water treatment is used to reduce the concentration of undesirable components in the water, for example suspended solids and pathogens, such as bacteria, algae, viruses and fungi.

For drinking water, countries have national standards for example including mineral content, pathogens and turbidity. For industrial water, other factors may apply, for example suspended particles may be problematic for some industrial machinery.

Applications such as industrial processes which require water as a resource or raw material, often produce waste water which may be exposed to the broader environment. Such industrial applications may therefore be required by local regulation to passivate said waste water such harm to the surrounding environment is minimised, often below specific thresholds determined by said regulation.

Such industrial waste water processing systems are often large, complex and non-portable solutions. Smaller water processing systems are often unable to cope with high-volume usage over long periods of time and as such may be unfit to manage waste water outputs of high-throughput industrial processes.

It is therefore desirable to provide a low cost, modular solution which is easy to maintain and which may be transportable.

Summary of the Invention

In accordance with a first aspect of the present invention, there is provided a water treatment apparatus for treating water comprising sediment, the apparatus comprising: a sediment settling system having a first water inlet arranged to receive the water comprising sediment, a water outlet arranged to outlet the water, and an aeration member positioned beneath the water outlet, the aeration member being arranged to provide a bubble curtain across the water outlet; and a flocculation system having a second water inlet arranged to receive water from the water outlet of the sediment settling system, an effluent outlet arranged to outlet an effluent liquid, a flocculating agent dosing member arranged to dose the water with a flocculating agent, and a flocculating agent dispersing member positioned downstream of the flocculating agent dosing member, the flocculating agent dispersing member being arranged to disperse the flocculating agent within the water.

The water treatment apparatus of the first aspect of the present invention preferably provides a compact and efficient apparatus which may be suitable for portable applications such as a mobile car wash. Non-portable, static embodiments will, however, be appreciated. Embodiments will also be appreciated wherein a scaled-up version of the invention may be employed in an industry-scale setting.

The dispersing member may disperse the flocculating agent such that the flocculating agent is evenly distributed in the water which is received from the sediment settling system. The dispersing member thereby preferably provides a roughly homogenous mixture of the water and the flocculating agent. In preferable embodiments, the flocculating agent dispersing member comprises an ultrasonic transducer. The ultrasonic transducer is preferably arranged to sonicate the flocculating agent at an ultrasonic frequency selected from between 40 kHz to 200 kHz. Sonication frequencies in the lower region of the range are preferred, such as frequencies between 40 kHz and 100 kHz, and most preferably between 60 kHz to 80 kHz. The ultrasonic transducer may be advantageous over other dispersing members due to the low-impact method of dispersal, resulting in no further chemical contamination of the water, and lower maintenance requirements compared to other dispersing members. A high-level of flocculating agent dispersal preferably results in a greater effective surface of said flocculating agent, which thus provides for more effective flocculation. Embodiments will of course be appreciated wherein the dispersing member is any equipment suitable for dispersing the flocculating agent in the water.

An aspect of the invention preferably includes the flocculating agent. In preferable embodiments, the flocculating agent comprises, an amount of flocculent; an amount of acid; and an amount of base. In accordance with preferable embodiments, the flocculent comprises an aluminium sulphate, wherein in most preferable embodiments, the aluminium sulphate is potassium aluminium sulphate. When the flocculating agent is dispensed into the water by the flocculating agent dosing member, the flocculating agent preferably provides a final flocculent concentration in the water. The final flocculent concentration in the water may be selected from the range: 10 pg/L to 500 pg/L. More preferably, the final flocculent concentration in the water is selected from the range: 10 pg/L to 100 pg/L. In most preferable embodiments, the final flocculent concentration is 70 pg/L.

The acid is preferably acetic acid, which may be in the form of white wine vinegar. When the flocculating agent is dispensed into the water by the flocculating agent dosing member, the flocculating agent preferably provides a final acid concentration in the water. The final acid concentration in the water may be selected from the range: 1 x 10-3 % (v/v) to 5 x 10-2 % (v/v). More preferably, the final acid concentration in the water is selected from the range: 1 x 10-3 % (v/v) to 1 x 10-2 % (v/v). In most preferable embodiments, the final acid concentration is 3 x 10-3 °h. (v/v). The acid, which is preferably a weak acid such as acetic acid in the form of white wine vinegar, may facilitate the continued cleaning and maintenance of the water treatment apparatus, while itself remaining a non-toxic agent. Preferably the acid facilitates in the clearing of oil and grease content within filtering components of the apparatus. Embodiments will be appreciated wherein any suitable acid may be used.

The base may be sodium bicarbonate. When the flocculating agent is dispensed into the water by the flocculating agent dosing member, the flocculating agent preferably provides a final base concentration in the water. The final base concentration in the water may be selected from the range: 10 pg/L to 500 pg/L. More preferably, the final flocculent concentration in the water is selected from the range: 10 pg/L to 100 pg/L. In most preferable embodiments, the final flocculent concentration is 30 pg/L. The sodium bicarbonate, or bicarbonate of soda, preferably aids in clearing oil-or grease-based content or soap content within the water.

The water treatment apparatus preferably further comprises a disinfection device for destroying microorganisms. The disinfection device preferably comprises at least one selected from the group: ozone; chlorine or a chlorine-containing compound; hydrogen peroxide; UV radiation. In embodiments wherein the disinfection device comprises UV radiation, the UV radiation is emitted from a UV lamp. UV radiation has the advantage of leaving no chemical residue in the water.

Preferably the flocculation system comprises a flocculation tank arranged to circulate the water received from the sediment settling system and the flocculating agent from the flocculating agent dosing member to produce a mixture of floc and effluent liquid, and a filter arranged to separate at least a portion of the floc from the effluent liquid. The flocculation tank preferably comprises the effluent liquid outlet arranged to provide the effluent liquid to the filter.

Preferably the disinfection device is positioned downstream of the filter. Preferably the filter comprises a sand filter. The sand filter may in some embodiments comprise a foraminous material layer, a pebble layer, and a sand layer. Preferably the sand filter comprises, in sequence, the foraminous material layer, the pebble layer, and the sand layer. In preferable embodiments the sand layer comprises a plurality of different sand or silica grades. In some embodiments the sand layer comprises a plurality of sublayers, each sublayer comprising sand of a different average sand or silica grade. In preferable said embodiments, the sublayers are sequentially arranged according to their respective sand or silica grade, the sand or silica grade increasing in size toward the pebble layer. The sand or silica grades preferably increases in size toward the pebble layer in order to aid backwashing. Larger sand or silica grades provide larger pores and thus permit easier flow of fluid therethrough. A lower pressure is preferably therefore required to push fluid through sublayers of the sand filter comprising larger pores. Backwashing of the sand filter preferably occurs by passing fluid in a reverse direction from the foraminous material layer, through the pebble layer, and upward through the sand layer. Having sand or silica of larger grades proximate the pebble layer than distal to the pebble layer preferably permits backwashing to occur at minimal pressure, and therefore preferably at minimal power requirement which may provide an economic benefit over alternative arrangements. Smaller sand grades may also have the effect of clogging the foraminous material layer.

The sand filter is preferably contained within a first filtration tank of the flocculation system, the first filtration tank comprising a tank body having an effluent liquid inlet arranged to receive effluent liquid from the effluent liquid outlet of the flocculation tank. The effluent liquid inlet is preferably positioned in an upper region of the tank body. The effluent liquid inlet preferably comprises a plurality of apertures arranged to produce an effluent liquid spray, the apertures arranged to spray the inlet effluent liquid onto the sand filter positioned therebeneath. The first filtration tank preferably comprises a first filtrate outlet positioned within the pebble layer of the sand filter. The first filtrate outlet preferably comprises a foraminous material, which may be a mesh or a gauze arranged to pass filtered effluent liquid into the first filtrate outlet of the first filtration tank. As such, in preferable embodiments, the sprayed effluent liquid descends through the sequential layers of the sand filter, including the sand layer, the pebble layer and the foraminous material to produce a first filtrate which exits the first filtration tank through the first filtrate outlet. In preferable embodiments, the first filtration tank comprises a first filtration tank pressure, the first filtration tank pressure being selectable between: 10 psi and 100 psi. Preferably the first filtration tank pressure is 25 psi. The pressure provides a continued flow of effluent liquid through the layers of the sand filter and out of the first filtrate outlet as the first filtrate. The foraminous material, which may be a gauze or mesh, preferably prevents particulate having an approximate size of >0.2mm escaping the first filtration tank through the first filtrate outlet. The first filtrate outlet is preferably submersed in the pebble layer, the pebble layer comprising roughly rounded pebbles, which may have a longest dimension of approximately 6 to 8 mm. The different grades of sand of the sand layer are preferably selected from between 0.2 mm and 0.8 mm.

The use of a sand layer having different sand grades is preferably useful as the varying grades may create a uniformly-structured filter bed. The greater amount of space positioned between the pebbles of the pebble layer, when compared to the space between the sand or silica grains of the sand layer, preferably aids "backwashing" of the sand filter. "Backwashing" will be understood as a term of the art referring to the practice of passing a fluid backwards through a filter for the purpose of cleaning or clearing the filter of blockages.

In some embodiments, if the foraminous material covering the first filtrate outlet was covered merely by the sand layer, said sand may be too densely-packed to permit effective backwashing and may instead act to clog the foraminous material.

The flocculation tank may be positioned above the sand filter, and may be positioned prior to (upstream of) a feeder tank or header tank positioned above the sand filter.

The water treatment apparatus may further comprise a turbidity filter. The turbidity filter may be located in a second filtration tank located downstream of the first filtration tank and having a first filtrate inlet arranged to receive the first filtrate from the first filtration tank. The turbidity filter preferably comprises a plurality of turbidity filter layers, the layers each comprising a turbidity filtration media having a different media grade to that of an adjacent layer. In preferable embodiments the first filtrate enters the second filtration tank in an upper region of the second filtration tank, and descends through the turbidity filter layers toward a second filtrate outlet, the turbidity filter layers having media grades of increasing density approaching the second filtrate outlet. The turbidity filter may comprise a sediment filter filled with a graded mixture of media, such as a zeolite filter media. The turbidity filter may be configured to remove sediment in the 0.5 to 10 micron range. More preferably, the turbidity filter may be configured to remove sediment in the 0.5 to 1.0 micron range. There are a range of suitable configurations of turbidity filters, for example curtain filters and membrane filters.

The water treatment apparatus may further comprise a microfiltration device positioned to receive liquid from the flocculation system and arranged to filter said liquid. In preferable embodiments, the liquid received by the microfiltration device from the flocculation system may be the first filtrate from the first filtration tank comprising the sand filter, or the second filtrate from the second filtration tank comprising the turbidity filter. The microfiltration device may comprise a micro filtration membrane. The micro filtration device may comprise a filter having pores of less than about 5 microns, less than about 2 microns or about 1 micron. The membrane may comprise a polypropylene filter.

The use of a microfiltration device may produce water with particulates of less than 1 micron. Not only does this meet drinking water standards but it is also useful for many industrial processes as the particulate size will not damage precision machinery.

The apparatus may comprise a TDS (Total Dissolved Solids) filter. Although this is not required to meet drinking water standards, it may be desirable to reduce the total dissolved solids identified following water analysis.

The sediment settling system preferably comprises a sequence of n sediment settling tanks, wherein n-1 of said sediment settling tanks is arranged to transfer water to an adjacent said sediment settling tank in the sequence via a syphon arrangement. The syphon arrangement preferably comprises a water outlet in an upper region of said n-1 sediment settling tanks, cooperating with a water inlet of the adjacent sediment settling tank. The water inlet and water outlet of each sediment settling tank are preferably located in an upper region of said sediment settling tank, and are preferably located at ends of the sediment settling tank distal to one another. In embodiments having water inlets and water outlets located at distal ends of each sediment settling tank preferably permits maximum travel of the water between the respective inlet and outlet, providing maximum opportunity for sedimentation.

Each of the sediment settling tanks in sequence may be positioned at a lower vertical position than the previous sediment settling tank in the sequence, with such an arrangement preferably being conducive to the syphon-based flow of water between the sediment settling tanks.

A sediment settling tank in the sequence may be positioned at a lower vertical position than the previous sediment settling tank in the sequence, the relative vertical positions being separated by a distance of about 5 to 15 cm, and more preferably about 10 cm. The sediment settling tanks are therefore preferably gravity fed and as such no pumps are required for the sediment settling system, thereby preferably minimising the power required for operation of the water treatment apparatus.

Each respective water outlet of a sediment settling tank in the sequence may have an internal diameter in the range of from about 8 mm to about 15 mm, and more preferably from about 10 mm to about 12 mm. Such an arrangement preferably produces a gentle trickle of water to a sediment settling tank in the sequence, from the previous tank in the sequence, with little turbulence. Such a minimisation in turbulence preferably aids the settling of particulates in the sediment settling system.

The nth sediment settling tank preferably comprises the water outlet and is thereby preferably arranged to provide the outlet water to the flocculation system. The outlet water is preferably provided by the nth sediment settling tank using a pump. Preferably, the pump is activated once the sediment settling tank reaches a threshold level of the water within the nth sediment settling tank. Preferably the pump is activated by a floating switch member.

The sediment settling tanks each preferably comprise one or more baffles or weirs, said baffles or weirs being arranged to minimise turbulence within the sediment settling tanks and thus encourage maximum sedimentation. The sediment settling tanks comprise an aeration member located beneath each respective water outlet. Preferably the aeration member comprises an aeration stone, through which a compressed gas (which may be compressed air) is passed to provide a bubble curtain across the respective water outlet. Preferably the bubble curtain acts to partially or fully occlude passage of sediment through the respective water outlet. Bubble forming by the aeration member may additionally traverse the surface of the water within each respective sediment settling tank. Said bubbles may therefore act to direct or drive sediment in a direction away from the water outlet and in a downward direction toward the base of the sediment settling tank.

The water outlet of a sediment settling tank may comprise a valve arranged to determine a flow rate of water into a corresponding adjacent sediment settling tank, wherein the flow rate may be freely adjustable by adjusting said valve. Preferably the valve is a ball valve.

In accordance with a second aspect of the present invention, there is provided a method of water treatment comprising the steps of: - separating sediment from the water in a sediment settling tank; - dosing the water with a flocculating agent; - dispersing the flocculating agent in the water; and - flocculating the water to produce an effluent liquid.

The dispersing preferably comprises sonicating the flocculating agent.

The method may further comprise the steps of - filtering the effluent liquid produced by the flocculation system and - destroying microorganisms using a disinfection device.

The method of the second aspect is preferably performed by a water treatment apparatus according to the first aspect.

The apparatus may comprise a support frame, and wherein the sediment settling system, flocculation system, disinfection device and microfiltration device are mounted on the support frame.

The support frame may comprise a mounting platform for components of the water treatment apparatus, such as the sediment settling system, the flocculation system, disinfection device and microfiltration device. The support frame is configured such that each mounting platform has a height and position so that its component is at the correct height and position when mounted on the mounting platform.

The sediment settling system may comprise three settling tanks in sequence, and wherein the mounting platform may comprise corresponding first, second and third settling tank mounting platforms, wherein the second settling tank mounting platform is positioned adjacent and lower than the first settling tank mounting platform, and wherein the third settling tank mounting platform is positioned adjacent and lower than the second settling tank mounting platform.

The support frame may be mounted on a vehicle or trailer. The water treatment apparatus is preferably easily transportable. This makes it particularly suitable for treating natural water sources, such as lakes and sources to provide drinking water. This is particularly useful where a temporary source of drinking water is required, for example for temporary camps, such as army camps, refugee camps or in humanitarian crises.

Preferred features of each aspect of the invention may be as described in connection with any of the other aspects. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible.

Detailed Description

Specific embodiments will now be described by way of example only, and with reference to the accompanying drawings, in which: FIG. 1 shows a plan view of a sediment settling system of an example embodiment of a water treatment system in accordance with the first aspect of the present invention, the sediment settling system having a first, second and third sediment settling tank in sequence; FIG. 2 is a lateral view of the sediment settling system of FIG. 1; FIG. 3A is a transverse sectional view of the second sediment settling tank of FIG. 1 and FIG 2; FIG. 33 is a longitudinal sectional view of the second sediment settling tank of FIG. 3A; FIG. 4A is a transverse sectional view of the third sediment settling tank of FIG. 1 and FIG. 2; FIG. 4B is a longitudinal sectional view of the third sediment settling tank of FIG. 4A; FIG. 5 is a perspective view of the support frame for the embodiment of Fig 1, and FIG. 6 is a flow chart depicting a method of water treatment according to the second aspect of the present invention.

A sediment settling system 100 as part of an example embodiment of a water treatment apparatus according to the first aspect of the present invention is illustrated from FIG. 1 to FIG. 43.

FIG. 1 shows a plan view of the sediment settling system 100, comprising a first sediment settling tank 102, a second sediment settling tank 104 and a third sediment settling tank 106 positioned in sequence and aligned along a central transverse plane. The first 102, second 104 and third 106 tanks are substantially cuboidal in shape and each comprise an open upper face and a cavity having a volume of around 1000 L. As can be seen in the lateral view of FIG. 2, the first 102, second 104 and third 106 tanks are positioned at varying respective points along a vertical axis, with the first tank 102 being raised roughly 10 cm relative to the second tank 104, which is in turn raised roughly 10 cm relative to the third tank 106. The first and second tanks 102, 104 are each raised by a corresponding platform 130 onto which each of the tanks 102, 104 is positioned.

The sediment settling system 100 further comprises a water inlet 112 comprising a water pipe 112 extending in a horizontal plane toward a point on the first sediment settling tank 102 proximate an upper edge thereof, as can be seen in FIG. 2. The inlet pipe 112 is in fluid communication with the first tank 102 through an aperture 113 in the first tank 102.

As shown in FIG. 1, the water inlet pipe 112 is positioned proximate a first widthwise end 108 of the first tank 102 distal to a second widthwise end 110 of the first tank 102.

Extending from proximate the uppermost edge of the first tank 102, and distal to the terminating end of the water inlet pipe 112 is a first syphon arrangement 118. The first syphon arrangement 118 extends in a horizontal plane above the second tank 104. The first syphon arrangement 118 extends in a first direction toward the second tank 104 proximate a first widthwise end 114, toward a right-angled bend in said arrangement 118. Subsequently, the arrangement 118 further extends in a second direction toward a second widthwise end 116 of the second tank 104 where the arrangement 118 terminates at an aperture through which water 119 syphoned from the first tank 102 is arranged to flow into the second tank 104.

Extending from proximate the uppermost edge of the second tank 106, and distal to the terminating end of the first syphon arrangement 118 is a second syphon arrangement 124. The second syphon arrangement 124 extends in a horizontal plane above the third tank 106. The second syphon arrangement 124 extends in a first direction toward the third tank 106 proximate a first widthwise end 120, toward a right-angled bend in said arrangement 124. Subsequently, the arrangement 124 further extends in a second direction toward a second widthwise end 122 of the second tank 106 where the arrangement 124 terminates at an aperture through which water syphoned from the second tank 104 is arranged to flow into the third tank 106.

Extending from a lower portion of the third tank 106, proximate the first end 120 of the third tank 106, is a water outlet 126 in communication with a water pump 128.

Sectional views of the second tank 104 are shown in FIG. 3A and FIG. 3B, with the transverse section of FIG. 3A showing the interior of the second tank 104 comprising a cavity 131. Extending inside the cavity 131 across the tank 104 and positioned roughly centrally along the height of the tank 104 is a baffle 132. The baffle 132 is positioned in fixed communication with opposing walls of the tank 104 such that it partially occludes or buffers longitudinal flow or current along the tank 104. Positioned at the base of the tank 104 proximate the first end 114 and beneath the outlet aperture leading to the second syphon arrangement 124 (as apparent from FIG. 3B) is an aeration stone 134 connected to a compressed air source (not shown).

The interior of the first tank 102 is substantially as shown in FIG. 3A and FIG. 3B for the second tank 104.

Similar views are provided for the third tank 106 in FIG. 4A and FIG. 4B. Unlike the second tank 104, the aeration stone 134 of the third tank 106 is not positioned beneath an outlet aperture. The third tank 106 additional comprises a water outlet 126 extending from a lower region of the third tank 106, and a water pump 128 in communication with, and arranged to be actuated by, a floating switch (not shown) located in the tank 106.

In use, the water inlet 112 channels water comprising sediment through the aperture 113 of the first tank 102 and into the cavity of the first tank 102. The first tank 102 subsequently fills with the water comprising sediment. Baffles 132 positioned within the first tank 102 limit turbulence within the water of the first tank 102 such that the particulate sediment in the water is allowed to settle at the base of the tank 102. An aeration stone 134 of the first tank 102 is positioned beneath the outlet aperture leading to the first syphon arrangement 118. Compressed air is provided from a compressed air source (not shown) and passed through the aeration stone 134 of the first tank 102 such that bubbles are emitted from the aeration stone 134 and pass within the first tank 102 along a bubble trajectory 121, shown as an example in relation to the second tank 104 in FIG. 3B. The bubbles from the aeration stone 134 initially form a bubble curtain proximate the first end 110 of the first tank 102, and across the outlet aperture leading to the first syphon arrangement 118. Bubbles from the bubble curtain act to occlude passage of sediment from the water through the outlet aperture into the first syphon arrangement 118. Subsequently, the bubbles pass along the surface of the water acting to push the sediment in a direction away from the outlet aperture. This has the effect of creating a sediment trajectory 123 which results in the sediment colliding with the baffles 132 and settling to the base of the first tank 102.

Water 119 syphoned from the first tank 102 using the first syphon arrangement 118 is syphoned into the second tank 104 at a position proximate the second end 116 of the second tank 104 and distal to the first end 114 from which outlet water is syphoned by the second syphon arrangement 124. As with the first tank 102 previously described, the second tank 104 fills with the water received from the first syphon arrangement 118. The baffles 132 act to reduce turbulence within the second tank 104 such that sediment is encouraged to settle at the base of the second tank 104. Bubbles are released from the aeration stone 134 of the second tank and follow the bubble trajectory 121 to occlude the outlet aperture of the second tank 104 leading to the second syphon arrangement 124. As with the first tank 102, the bubbles follow a trajectory along the surface of the water as shown in order to direct the sediment away from the outlet aperture and down toward the base of the second tank 104. Water 125 is syphoned from the second tank 104 by the second syphon arrangement 124 and into the third tank 106, which fills in the same way as the first tank 102 and the second tank 104. The third tank 106 comprises an aeration stone 134 which is equivalent to the aeration stones 134 of the first tank 102 and the second tank 104, and produces bubbles following the same trajectory as that previously described.

As a result, the sediment in the water is caused to settle at the base of the tank 106 by the bubbles in combination with the baffles 132. Once the third tank 106 fills above a threshold level, a floating switch (not shown) is actuated, activating the pump 128 which pumps water from the third tank 106 through the water outlet 126 toward a flocculation system.

A suitable flocculation system 200 as part of an example embodiment of a water treatment apparatus according to the first aspect of the present invention is illustrated in FIG. 5. Flow of water received from the sediment settling system of FIG. 1 to FIG. 4B and through the flocculation system 200 is shown depicted in FIG. 5 using arrows. The flocculation system comprises a water inlet pipe 202 leading to a flocculation tank 208 in which the water inlet pipe 202 terminates at an outlet nozzle 210. Prior to extension within the flocculation tank 208, the water inlet pipe 202 passes adjacent to a flocculating agent dosing device 204 comprising a cavity housing a flocculating agent (not shown). The flocculating agent in the embodiment 200 shown comprises potassium aluminium sulphate (added to the water in a final concentration of 70 pg/L, or 70 mg per 1000 L); white wine vinegar (added to the water in a final concentration of 3 x 10-3 % (v/v), or 30 mL per 1000 L); and bicarbonate of soda (added to the water in a final concentration of 30 pg/L, or 30 mg per 1000 L). The flocculating agent dosing device 204 comprises an aperture positioned adjacent a corresponding aperture of the water inlet pipe 202, each aperture having a diameter of approximately 6 mm. The size of the corresponding apertures of the flocculating agent dosing device 204 and the water inlet pipe 202 are such that flocculating agent from the flocculating agent dosing device 204 is dosed into water flowing adjacent thereto. Downstream of the flocculating agent dosing device 204 and upstream of the flocculating tank 208 is a flocculating agent dispersing member 206 taking the form of an ultrasonic transducer 206. The ultrasonic transducer is arranged to emit ultrasonic waves at a frequency of around 60 kHz to 80 kHz in the direction of the water inlet pipe 202 passing adjacent thereto. In use the ultrasonic transducer 206 acts to agitate the flocculating agent in the water such that agglomerations or particles of the flocculating agent are reduced in size and are roughly evenly dispersed within the water.

The flocculation tank 208 comprises a cavity therein into which the outlet nozzle 210 is arranged to outlet the water and flocculating agent mixture such that it fills the tank 210. The flocculating tank 208 and outlet nozzle 210 therein are positioned at an angle relative to the plane of the ground such that a current is formed within the tank 208 causing the water and flocculating agent to mix. During said mix, or flocculation, contaminating particles within the water are agglomerated to form larger clumps and clusters (floc) within the water.

The flocculation tank 208 comprises a water outlet 212 therein, downstream of which is positioned a pump 214. The pump 214 is arranged to be actuated when the water in the flocculation tank 208 reaches an upper threshold level. Upon reaching the upper threshold level, and following consequential actuation of the pump 214, the water and floc mixture from the flocculation tank 208 is pumped through the outlet 212 toward a multidirectional port 216 arranged to direct the water and floc mixture into a first filter tank 218 and through a spray nozzle 220 positioned in an upper region of the first filter tank 218. Positioned in the lower region of the filter tank 218 is a sand filter, the sand filter comprising an upper first layer 224 and lower second layer 226. The upper first layer 224 of the sand filter comprises silica granules sequentially stratified into a series of silica sublayers (strata), the sublayers each having a higher grade of granular silica as the layers approach the lower second layer 226. The silica grades proceeding sequentially through the sublayers of the upper first layer 224 of the sand filter toward the lower second layer 226 each have silica grades (particle diameters) ranging between 0.2 mm and 0.8 mm. The lower second layer 226 is comprised of rounded pebbles having an average diameter of roughly 7 mm.

Located within the lower second layer 226 (the pebble layer 226) is a first filtrate outlet 228, the first filtrate outlet 228 being arranged to accept water filtered through the sand filter (the first filtrate) and channel the first filtrate toward the multidirectional port 216. The first filtrate outlet 228 is covered by a material gauze having pores of average diameter of roughly 0.2 mm. The gauze therefore prevents passage of particulate having a diameter of greater than 0.2 mm through the first filtrate outlet 228. The water is urged through the upper layer 224 and lower layer 226 of the sand filter and into the first filtrate outlet 228 due to a pressure exerted upon the interior of the first filtration tank 218 by a compressor 222. The interior of the first filtration tank 218 is placed under a pressure of roughly 25 psi.

From the multidirectional port 216, the first filtrate is channelled toward a second filtration tank 232 through a second filtration tank inlet/outlet port 230 where the first filtrate flows into the interior of the second filtration tank 232. The second filtration tank 232 comprises a turbidity filter having a first upper turbidity filter media 234 and a second lower turbidity filter media 236, the upper turbidity filter media 234 having pores formed therein of average diameter that are greater than an average diameter of pores formed in the lower turbidity filter media 236. Located within the second turbidity filter media 234 is a second filtrate outlet 238. The first filtrate is urged through the turbidity filter under a pressure of 25 psi and out of the second filtration tank 232 (as a second filtrate) through the second filtrate outlet 238. The second filtrate is then urged, under the pressure of 25 psi, toward, and through, a microfiltration device 240. The microfiltration device 240 comprises two 10 inch polypropylene microfilters positioned in sequence, each having pores of an average pore size of 1 micron. In use the microfiltration device 240 can have a transparent surface permitting visibility to the microfilters therein, such that the microfilters may act as one visual diagnostic indication of the healthy functioning of the water treatment apparatus. In normal use, wherein the combined sediment settling system 100 and flocculation system 200 are working normally, the microfilters of the microfiltration device should appear clear of any contaminant. If any aspect of the system is malfunctioning, a presence of contaminant in the second filtrate, and resultant discolouring of the microfiltration device may occur.

The second filtrate passes through the microfilters and out of the microfiltration device 240 (as a microfiltrate) and the microfiltrate passes toward, and through a UV sterilisation lamp 242 for disinfection, to provide a disinfected outlet flow.

The disinfected outlet flow then flows through a flow gauge 244 before flowing through an outlet 246 of the water treatment apparatus 100, 200.

The apparatus 100, 200 is operated using the corresponding pumps described which are powered by a 240 V power supply in the embodiment shown.

FIG. 6 depicts a method of treating water 300 according to the second aspect of the present invention, the method 300 comprising the steps of: separating sediment from the water in a sediment settling system and outputting water 302; dosing the water with a flocculating agent 304; dispersing the flocculating agent in the water 306; flocculating the water to produce an effluent liquid 308; filtering the effluent liquid to produce a filtrate 310; and disinfecting the filtrate 312.

The method 300 as shown in FIG. 6 is arranged to be performed by a water treatment apparatus 100, 200 as shown and described in relation to FIG. 1 to FIG. 5.

It will be appreciated that the above described embodiments are given by way of example only and that various modifications may be made to the described embodiments without departing from the scope of the invention as defined in the appended claims. For example, in the embodiments shown, compressed air is passed through the aeration stones to form the bubble curtain. In alternate embodiments, the compressed gas may be chlorinated or comprise ozone, and may additionally act to deodorize or otherwise disinfect the water. Valves may be present on the compressed gas tanks feeding the aeration stones such that a less-dense (or contrastingly more dense) bubble curtain may be provided for the first tank relative to the second tank, and additionally in the second tank relative to the third tank. Accordingly, a denser bubble curtain may serve to occlude larger particles and sludge, whereas a less-dense bubble curtain may provide occlusion to movement of smaller particles. In such a way, the bubble curtain may be tailored by said valves to "sort" sediment according to size or type. A single aeration pump may connect to a manifold which supplies air to each tank. Adjustable valves may be used to achieve variable aeration in the different tanks.

The water treatment apparatus as shown undergoes a periodic backwashing process to clean the filters. The backwashing process uses a pump to reverse the flow of water, which may be clean water fed into the apparatus through the water outlet of the apparatus, and thereby lift the filtering media on both the sand filter and the turbidity filter.

The invention may additionally be understood in view of the below description: The whole system may use only two pumps and is therefore very low on running costs. The water treatment system is preferably a closed loop system and is topped up with fresh water to maintain a desired pH level. A ratio of waste water: fresh water of 8: 2 has been found to sustain a pH level of 7.4.

The use of a frame support for the combined components of water treatment apparatus preferably enables the water treatment apparatus to be assembled very quickly in situ, which his important where it is used in a temporary situation, for example emergency aid. As the frame has mounting platforms for each of the components of the water treatment apparatus, it ensures that the position and height of each of the component is correct, once it has been positioned on its respective mounting platform.

Example 1

A sample of water which was surface run off from a car wash was treated with the water treatment apparatus described above. Surface run off from a car wash is typically contaminated with grass, mud, animal dung, stick leaves, other debris, oil and grease.

Water samples were taken from the third settling tank, and post sand filter.

Analysis Results Results Results Units Maximum description (Tank 14) (Sand filter (Tank 3) Limit/Value 22) pH 6.6 7.0 7.2 6.5-9.5 Conductivity at 20C 397 417 400 pS/cm 2500 Suspended 77 4 <2 mg/L solids Suspended 51 2 < 1 mg/L Solids (ignited) Turbidity 117.0 409 1.2 NTU 4 Total solids 307 269 mg/L (Dry Res) As expected, the water analysis showed the water sample taken from the apparatus had a high turbidity level of 117.0. However, this is low considering the sample was from a settling tank.

Water analysis from water exiting the sand filter shows that the sand filters are capturing most of the fine particulate which is <2. Furthermore the surface charge of the suspended particles has been neutralised, leaving a pH value of 7.0.

Water analysis from the water apparatus, stored in a storage tank, gave a turbidity level of < 1.2, which is well below the level of 4NTU set by the UK Water Supply (VVater Quality) Regulations 2016. Furthermore, the sample is inorganic, which shows that the UV steriliser is killing micro-organisms.

Example 2

A sample of water from a farmyard pond was treated using the water treatment apparatus described above. The table below shows the analysis of water before and after treatment and compares with maximum allowed values for drinking water in the UK.

Analysis Results Results Units Maximum UKAS

description (before (after Limit/Value Status

treatment) treatment Turbidity > 240.0 0.2 NTU 4 Yes Aluminium 4497.00 9.58 pg/L 200 Yes Iron 8676.00 <2.03 pg/L 200 Yes Manganese 904.80 0.73 pg/L 50 Yes Each of the analysed components has been dramatically reduced and is within allowable limits for drinking water. All the tested water components/ water qualities met the United Kingdom Accreditation Service (UKAS) standard. In particular, the turbidity is well below the level of 4NTU set by the UK Water Supply (Water Quality) Regulations 2016.

Example 3

A sample from a 3 5 metre deep borehole consisting of heavy clay particulates was treated using the water treatment apparatus described above. The table below shows the analysis of water before and after treatment and compares with maximum allowed values for drinking water in the UK.

Analysis Results Results Units Maximum UKAS

description (before (after Limit/Value Status

treatment) treatment) Turbidity >240.0 0.1 NTU 4 Yes Aluminium 54450.00 16.97 pg/L 200 Yes Iron 4939.0 Greater than pg/L 200 Yes 11.76 Manganese 119.80 3.76 pg/L 50 Yes Each of analysed components has been dramatically reduced and is within allowable limits for drinking water. In particular, the turbidity is well below the level of 4NTU set by the UK Water Supply (Water Quality) Regulations 2016.

The invention will now be defined by reference to the following clauses: A water treatment apparatus for treating water comprising sediment, the apparatus comprising: a sediment settling system having a first water inlet arranged to receive the water comprising sediment, a water outlet arranged to outlet the water, and an aeration member positioned beneath the water outlet, the aeration member being arranged to provide a bubble curtain across the water outlet; and a flocculation system having a second water inlet arranged to receive water from the water outlet of the sediment settling system, an effluent outlet arranged to outlet an effluent liquid, a flocculating agent dosing member arranged to dose the water with a flocculating agent, and a flocculating agent dispersing member positioned downstream of the flocculating agent dosing member, the flocculating agent dispersing member being arranged to disperse the flocculating agent within the water.

2. A water treatment apparatus as stated in clause 1, wherein the flocculating agent dispersing member comprises an ultrasonic transducer.

3. A water treatment apparatus as stated in clause 2, wherein the ultrasonic transducer is arranged to sonicate the flocculating agent at an ultrasonic frequency selected from between 40 kHz to 200 kHz.

A water treatment apparatus as stated in clause 1, clause 2 or clause 3, wherein the flocculating agent comprises, an amount of flocculent; an amount of acid; and an amount of base.

A water treatment apparatus as stated in clause 4, wherein the flocculent is an aluminium sulphate.

A water treatment apparatus as stated in clause 4 or clause 5. wherein the aluminium sulphate is potassium aluminium sulphate.

A water treatment apparatus as stated in any one of clauses 4 to 6, wherein the flocculent is present in the water at a final flocculent concentration selected from the range: 10 pg/L to 500 pg/L.

A water treatment apparatus as stated in any one of clauses 4 to 7, wherein the acid is acetic acid.

A water treatment apparatus as stated in clause 8, wherein the acetic acid is in the form of white wine vinegar.

10. A water treatment apparatus as stated in any one of clauses 4 to 9, wherein the acid is present in the water at a final acid concentration selected from the range: 1 x 10-3 % (v/v) to 5 x 10-2 % (v/v).

11. A water treatment apparatus as stated in any one of clauses 4 to 10, wherein the base is sodium bicarbonate.

12. A water treatment apparatus as stated in any one of clauses 4 to 11, wherein the base is present in the water at a final base concentration selected from the range: 10 pg/L to 500 pg/L.

13. A water treatment apparatus as stated in any one of the preceding clauses, further comprising a disinfection device for destroying microorganisms.

14. A water treatment apparatus as stated in clause 13, wherein the disinfection device comprises ozone, chlorine or a chlorine-containing compound, hydrogen peroxide, or UV radiation.

15. A water treatment apparatus as stated in any one of the preceding clauses, wherein the flocculation system comprises a flocculation tank arranged to circulate the water from the sediment settling system and the flocculating agent from the flocculating agent dosing member to produce a mixture of floc and effluent liquid, and a filter arranged to separate at least a portion of the floc from the effluent liquid.

16. A water treatment apparatus as stated in clause 15, wherein the filter comprises a sand filter, the sand filter comprising, in sequence, a foraminous material layer, a pebble layer, and a sand layer comprising a plurality of different sand grades.

17. A water treatment apparatus as stated in any one of the preceding clauses, further comprising a microfiltration device positioned to receive the effluent liquid from the flocculation system and arranged to filter said effluent liquid.

18. A water treatment apparatus as stated in any one of the preceding clauses, wherein the microfiltration device comprises a micro filtration membrane.

19. A water treatment apparatus as stated in clause 16, wherein the micro filtration membrane comprises a filter of less than about 5 microns, less than about 2 microns or about 1 micron.

20. A water treatment apparatus as stated in any one of the preceding clauses, wherein the sediment settling system comprises a sequence of n sediment settling tanks, wherein n-1 of said sediment settling tanks is arranged to transfer water to an adjacent said sediment settling tank in the sequence via a syphon arrangement.

21. A water treatment apparatus as stated in clause 21, wherein the syphon arrangement comprises a water outlet in an upper region of said n-1 sediment settling tanks.

22. A water treatment apparatus as stated in clause 22, wherein the outlet comprises a valve for adjusting the flow rate of water to the corresponding adjacent sediment settling tank.

23. A method of water treatment comprising: separating sediment from the water in a sediment settling tank; dosing the water with a flocculating agent; dispersing the flocculating agent in the water; flocculating the water to produce an effluent liquid.

24. A method as stated in clause 23, wherein the dispersing comprises sonicafing the flocculating agent.

25. A method as stated in clause 23 or clause 24, wherein the method further comprises the steps of: filtering the effluent liquid produced by the flocculation system using a micro filtration device; and destroying microorganisms using a disinfection device.

Claims

CLAIMS1. A water treatment apparatus for treating water comprising sediment, the apparatus comprising: a sediment settling system having a first water inlet arranged to receive the water comprising sediment, a water outlet arranged to outlet the water, and an aeration member positioned beneath the water outlet, the aeration member being arranged to provide a bubble curtain across the water outlet; and a flocculation system having a second water inlet arranged to receive water from the water outlet of the sediment settling system, an effluent outlet arranged to outlet an effluent liquid, a flocculating agent, a flocculating agent dosing member arranged to dose the water with the flocculating agent, and a flocculating agent dispersing member positioned downstream of the flocculating agent dosing member, the flocculating agent dispersing member being arranged to disperse the flocculating agent within the water.
2. A water treatment apparatus as claimed in claim 1, wherein the flocculating agent dispersing member comprises an ultrasonic transducer.
3. A water treatment apparatus as claimed in claim 2, wherein the ultrasonic transducer is arranged to sonicate the flocculating agent at an ultrasonic frequency selected from between 40 kHz to 200 kHz.
A water treatment apparatus as claimed in claim 1, claim 2 or claim 3, wherein the flocculating agent comprises, an amount of flocculent; an amount of acid; and an amount of base.
5. A water treatment apparatus as claimed in claim 4, wherein the flocculent is an aluminium sulphate
6. A water treatment apparatus as claimed in claim 4 or claim 5, wherein the aluminium sulphate is potassium aluminium sulphate.
7. A water treatment apparatus as claimed in any one of claims 4 to 6, wherein the flocculent is present in the water at a final flocculent concentration selected from the range: 10 pg/L to 500 pg/L.
A water treatment apparatus as claimed in any one of claims 4 to 7, wherein the acid is acetic acid.
A water treatment apparatus as claimed in claim 8, wherein the acetic acid is in the form of white wine vinegar.
10. A water treatment apparatus as claimed in any one of claims 4 to 9, wherein the acid is present in the water at a final acid concentration selected from the range: 1 x103 % (WV) to 5 x 1 0-2 % (vlV).
11. A water treatment apparatus as claimed in any one of claims 4 to 10, wherein the base is sodium bicarbonate.
12.A water treatment apparatus as claimed in any one of claims 4 to 11, wherein the base is present in the water at a final base concentration selected from the range: 10 pg/L to 500 pg/L.
13. A water treatment apparatus as claimed in any one of the preceding claims, further comprising a disinfection device for destroying microorganisms.
14. A water treatment apparatus as claimed in claim 13, wherein the disinfection device comprises ozone, chlorine or a chlorine-containing compound, hydrogen peroxide, or UV radiation.
15. A water treatment apparatus as claimed in any one of the preceding claims, wherein the flocculation system comprises a flocculation tank arranged to circulate the water from the sediment settling system and the flocculating agent from the flocculating agent dosing member to produce a mixture of floc and effluent liquid, and a filter arranged to separate at least a portion of the floc from the effluent liquid.
16. A water treatment apparatus as claimed in claim 15, wherein the filter comprises a sand filter, the sand filter comprising, in sequence, a foraminous material layer, a pebble layer, and a sand layer comprising a plurality of different sand grades.
17. A water treatment apparatus as claimed in any one of the preceding claims, further comprising a microfiltrafion device positioned to receive the effluent liquid from the flocculation system and arranged to filter said effluent liquid.
18. A water treatment apparatus as claimed in any one of the preceding claims, wherein the microfiltration device comprises a micro filtration membrane.
19. A water treatment apparatus as claimed in claim 16, wherein the micro filtration membrane comprises a filter of less than about 5 microns, less than about 2 microns or about 1 micron.
20. A water treatment apparatus as claimed in any one of the preceding claims, wherein the sediment settling system comprises a sequence of n sediment settling tanks, wherein n-1 of said sediment settling tanks is arranged to transfer water to an adjacent said sediment settling tank in the sequence via a syphon arrangement.
21. A water treatment apparatus as claimed in claim 21, wherein the syphon arrangement comprises a water outlet in an upper region of said n-1 sediment settling tanks.
22. A water treatment apparatus as claimed in claim 22, wherein the outlet comprises a valve for adjusting the flow rate of water to the corresponding adjacent sediment settling tank.
23. A method of water treatment comprising the apparatus of any one of claims 1 to 20, the method comprising: separating sediment from the water in the sediment settling tank system; dosing the water with a flocculating agent; dispersing the flocculating agent in the water; flocculating the water to produce an effluent liquid.
24. A method as claimed in claim 21, wherein the dispersing comprises sonicating the flocculating agent.
25. A method as claimed in claim 21 or claim 22, wherein the method further comprises the steps of: filtering the effluent liquid produced by the flocculation system using a micro filtration device; and destroying microorganisms using a disinfection device.