WATER REMEDIATION SYSTEM

Abstract

A water remediation system and accompanying method includes remediation by reducing the concentration of nutrients in the water and dosing the water with metal ions. It has been found that through a combination of reducing nutrients present in the water and treating with metal ions, the requirement to treat with high chemical dosages is removed.

Claims

1. A method of remediating water comprising: reducing the concentration of nutrients in the water; dosing the water with metal ions.

2. The method according to claim 1 wherein the dosing step comprises dosing zinc and/or titanium ions into the water.

3. (canceled)

4. The method according to claim 1, wherein the dosing agent comprises a metal compound dissolved in a carrier, where the carrier is an acid.

5. The method according to claim 1, wherein a suitable metal compound is a metal oxide.

6. The method according to claim 1, wherein the step of dosing the water with metal ions is performed by electrolysis.

7. The method according to claim 1, wherein the metal ions are dosed to a concentration of metal in the water of less than 5 mg/L, even more preferably less than 3 mg/L.

8. The method according to claim 4 wherein a concentration of metal ions in the dosing agent is between 20 and 100 g/l, even more preferably between 50 and 90 mg/l, and even more preferably approximately 80 g/l.

9. The method according to claim 1, wherein the step of reducing the concentration of nutrients in the water comprises filtering the nutrients from the water.

10. (canceled)

11. The method according to claim 9 wherein the filter is a mechanical sieve filter.

12. The method according to claim 9 wherein the filter is an ion exchanger.

13. The method according to claim 1, wherein the step of reducing the concentration of nutrients in the water may comprise dosing the water with a flocculant to cause the nutrients to combine with the flocculant to form a floc.

14. The method according to claim 1, comprising the step of applying UV light to the water.

15. The method according to claim 1, further comprising controlling the pH of the water to be range from 7.5-8.5, even more preferably between 7.9-8.3.

16. The method according to claim 1, comprising oxygenating the water with a venturi across micro tubules.

17. The method according to claim 1, comprising supersaturating the water using an oxygen concentrator apparatus.

18. A water remediation system comprising: an arrangement for reducing nutrients in the water; metal ions for algae and/or pathogen control; a delivery arrangement for delivering the metal ions into the water.

19. (canceled)

20. The water remediation system according to claim 18, wherein the delivery arrangement comprises a pump and a container for receiving the metal ions to be delivered, the pump arranged to pump the metal ions from the container into the water.

21. The water remediation system according to any claim 18, wherein the delivery arrangement comprises an electrolysis apparatus.

22. The water remediation system according to claim 18, wherein the arrangement for reducing nutrients in the water comprises a filter.

23. A water remediation system according to claim 22 wherein the filter comprises an ion exchange resin and or adsorbent.

24. (canceled)

25. (canceled)

26. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Aspects of the present invention will now be described by way of illustration only with reference to the accompanying drawings where:

[0060] FIG. 1 is a schematic representation of a water treatment system according to an illustrative embodiment of the present invention;

[0061] FIG. 2 is a schematic representation of an illustrative filter for reducing the nutrients in a system according to an illustrative embodiment of the present invention; and

[0062] FIGS. 3a and b are schematic representations of filter media in the filter as presented in FIG. 2 according to an illustrative embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0063] Nutrients such as phosphorus, carbon and nitrogen are key nutrients required by all organisms for the basic processes of life and is therefore control of these nutrients is a limiting factor when it comes to the growth of algae or multiplication of pathogenic bacteria. Phosphorus in pool water is usually found in the form of phosphates. Phosphates can be in inorganic form (including orthophosphates and polyphosphates), or a more complex, organic form (organically bound phosphates). Organics in water may be in dissolved, suspended, settled, or floating states.

[0064] Inorganic orthophosphates and /or polyphosphates are generated when complex organically bound phosphates (from swimmer or environmental input) break down into simpler, ortho phosphorous compounds which are more reactive with algal cells and bacteria. Once this process occurs, these molecules become highly bio-available to algae and other life forms (e.g. pathogenic aquatic bacteria) and cannot easily be removed purely by mechanical filtration without the need for coagulants or removal via dilution of the pool water.

[0065] The majority of current filtration systems fail to effectively and continually remove both organic and inorganic nutrients (in particular phosphates). In particular, various forms of algae are well evolved at utilising nutrients to grow, and in a non-limited carbon or nitrogen environment, it is known that as little as 3 mg of phosphorous can result in 1 dry Kg of algal matter.

[0066] Instead of dealing with the causes of algal and pathogen growth (ie: nutrient load), the majority of current pool water treatment and filtration systems deal with the potential effects of high nutrients (ie: algae and aquatic pathogens) in the water. This is usually achieved by utilising basic mechanical filtration (eg: a sand filter), in combination of excessive and unnecessary chemical usage whilst also requiring high rates of water circulation, thereby creating unnecessary electrical demand.

[0067] With reference now to FIG. 1 a schematic representation of a system 2 according to an illustrative embodiment of the present invention is presented. In this system there is both the provision of a dosing arrangement 4 capable of dosing metal ions (preferably zinc ions) into the water to be treated and the provision of a nutrient reducing arrangement for reducing the concentration of nutrients present in the water comprising a first stage arrangement 6. In the schematic diagram represented a second stage 7 for reduction of nutrients in the water is presented which will be described further below and is in effect a back-up or auxiliary stage.

[0068] Referring to FIG. 1 from left to right a water remediation system 2 is presented having an inlet 8 which passes through a non-return valve 10. Water then passes through a valve 12 in a form of a ball valve which can be used to shut off water passage through the water remediation system 2 as required for, for example, maintenance purposes. A water pump 14 is then provided which may comprise, for example, a 1.1 kW pump having a power output appropriate to the size of system in which it is installed. The flow path passes through a further valve 16 and into a further valve arrangement 18 which is arranged to enable a change of water flow direction into the first stage arrangement 6. In a first configuration the valve 18 allows water flow which is directed to top of the first stage arrangement 6 when which the water flow passes through the first stage arrangement 6 and out of the lower end and then passes back to the valve 18. This is the normal operational state of the water treatment system 2. However, valve 18 enables a backwash configuration whereby the flow direction through the first stage arrangement 6 is changed meaning that the flow passes from the lower end of the first stage arrangement 6 out through the upper end and back to the valve 18 and then out of the valve 18 to the waste outlet 20. The first stage arrangement 6 is beneficially a filter arrangement and as such after a pre-determined period of time the filter will have captured solid matter which must be cleared from the filter.

[0069] Under normal operation water passing from the first stage arrangement 6 back to the valve 18 will then travel through a flow meter 22 which measures the rate of flow through the system, through a further valve 24 and into a second stage arrangement 7. Operation of the second stage arrangement 7 will be described in more detail below. Water then exits the second stage arrangement 7, passes through a further flow meter 26, further valve 28 and passes by dosing arrangement 4 capable of dosing metal ions into the water to the treated. Further optional but preferable features of the water remediation system 2 comprise a UV treatment stage 30, a further dosing arrangement 32 and an oxygen diffuser 34. A sensor 36 may be provided for measuring temperature of the water passing through the water remediation system 2. An outlet 40 is then provided. The outlet in a pool system is connected to a pool inlet where treated water is fed back into the pool.

[0070] A control system 38 is provided for controlling operation of the water treatment system 2 in response to measured parameters. Feedback is provided in real time with respect to monitored attributes of the water, such as pH and metal ion concentration such as a heavy metal sensor. In one mode the dosing pump 4 can be triggered to dose a temporary shock dose of metal ions in order to clear any temporary problem of excess algae or water quality, or in the event of for example a high nutrient event such as a pool party or dust storm. The control system also beneficially operates control of the valve 18 to cause a backwash cycle of the first stage filter arrangement 6.

[0071] A further sensor may be provided for monitoring turbidity and provides feedback in real time to the control system in order that dosing of the metal ions can be adjusted dependent on measured values.

[0072] In one aspect the delivery arrangement for delivering metal ions into the water comprises a dosing arrangement such as a dosing pump that dispenses metal ions from a container. The metal ions can be dosed as required and the container replenished as necessary. In an alternative embodiment however the delivery arrangement may comprise an electrolysis apparatus. The electrolysis apparatus comprises an anode and a cathode configured such that the water is between the anode and cathode which may be made of known suitable materials such as carbon, titanium or steel. Current is passed between the anode and cathode through the water. In one embodiment a metal such as zinc in the form of a rod or sheet for example is introduced in the current pathway flowing between the anode and cathode causing ionisation and thus providing zinc ions in the water. In another embodiment zinc may be used as the anode and/or the cathode which has the same effect of delivering zinc ions into the water.

[0073] In one embodiment the first stage arrangement 6 comprises a mechanical nutrient reducing arrangement for reducing the concentration of nutrients present in the water and comprises a filter as presented in an illustrative embodiment in FIG. 2. Presented is a housing 102 defining a filtration chamber 104 therein. The housing 102 comprises a connector 103 and a pathway 104 extending from the connector 103 to an inlet 106 provided at the upper end of the filtration chamber 104 for releasing water into contact with the filter media. A water collector 108 in the form of an outlet is positioned at the lower end of the filtration chamber 104 for collecting water that has passed through the filter media which in turn transfers the water through pathway 110 and out through a second connector 112.

[0074] Provided within the filtration chamber 104 is filter media comprising a plurality porous filtration beads 114. The generally spherical beads 114 themselves are schematically presented in FIG. 3a and are porous through the entire bead. Such a structure provides structural integrity whilst maximising the surface area for bacteria to inhabit and maximises the contact area for the water flow. This further maximises the surface area of the beads. The beads have a dry density of approximately 0.35 kg/litre. The relatively low density means that the backwash water pressure (which is when the flow direction is reversed in order to clean the beads and remove solid matter from the filter) is reduced due to the natural positive buoyancy of the beads. The beads 114 themselves however will not float due to their inherent porosity but will readily become agitated during the backwash process. The beads 114 comprise a diameter of between 15-25 mm with a diameter tolerance of +/-2 mm. The beads 114 are preferably ceramic which has been found to provide improved adhesion for bacteria when used as a biofilter.

[0075] The beads are unconstrained in the chamber. This means that the beads are able to readily move and rearrange their relative positions during a backwash cycle thereby improving the ability to effectively clean the beads. During a backwash cycle when the flow direction is reversed a valve (not shown) is closed to prevent water exiting through the inlet 103 and dirty water exits the chamber 104 from an upper end of the housing 102, controlled by another valve (not shown).

[0076] Provided within the filter chamber 104 are a plurality of secondary filter media 116 also schematically represented in FIG. 2b. The secondary filter media comprises a plurality of substantially non-porous filtration media. There is no segregation between the primary and secondary filter media. The secondary filter media comprises a silicate such as glass and is not porous.

[0077] The primary and secondary filter media are beneficially not segregated from each other in the chamber. The secondary beads preferably have a negative buoyancy, meaning they sink in water. The density of the secondary beads is greater than 1 kg/litre. The secondary filter media 116 has a maximum dimension of between 0.8-1.0 mm. It is beneficial that the secondary filter media has a size gradient between 0.2 mm and 1.5 mm. The combination of smaller to larger secondary filter media improves particle separation. It will be appreciated that due to the difference in densities, the primary and second filter media do not mix in the chamber, and the primary filter media sits above the secondary filter media.

[0078] In operation the secondary filter media act as a particulate filter thereby trapping particulate matter that is present in the water. This trapped matter is held until the filter is backwashed, and which time the particulate matter rises to the surface of the water in the filter and can be mechanically removed. Such secondary filter media can beneficially trap particulate material as small as 4 microns. The primary filter acts to control the phosphate levels in the water. In a preferred embodiment the beads 114 are at least partially coated with a bacterial culture.

[0079] Alternative embodiments of the first stage arrangement 6 will now be described.

[0080] In an alternative embodiment, the first stage arrangement 6 may comprise a dosing arrangement may be provided for dosing an additive (e.g. a flocculant) into the water. A flocculant is beneficial for removal of solid materials suspended in water. The floc can be removed by mechanical means such as a filter as the floc floats to the surface (flotation) or settles to the bottom (sedimentation). Alternatively, the floc may be removed by a mechanical means, for example may be sucked from the floor of a swimming pool. Suitable flocculants include for example aluminium sulphate (alum). Another means of introducing flocculant to the water is to dose the water with iron ions. This may be achieved both through dosing as a solid or liquid via a dosing arrangement, or alternatively through electrolysis.

[0081] In an alternative embodiment other filter configurations are suitable for nutrient removal and may comprise fine filters utilising physical particulate removal without beads as described above.

[0082] In an alternative embodiment another first stage arrangement may be to utilise a nutrient adsorbing filter comprising an ion exchanger. The ion exchanger may comprise for example activated alumina or iron hydroxide. This has the effect of removing phosphorous via an ion exchange and adsorption process. Such ion exchangers are replaceable as the ion exchanger is used up and becomes saturated over time.

[0083] It will be appreciated that alternative methods and associated apparatus have been described for reducing nutrients in the water. It will also be appreciated that combinations of each may be included in a water remediation system. For example, in the system as described with reference to FIG. 1 both a biofilter and an ion exchange resin / adsorbent are utilised in tandem for improved nutrient reduction.

[0084] The system as presented in FIG. 1 comprises an arrangement for oxygenating the water in the form of the oxygen diffuser 34. This diffuser 34 may comprise a known oxygenator such as a hollow fibre oxygenator. A pump (not shown) may be provided to feed air to the hollow fibre oxygenator. Alternatively, microbubbles can be generated using a passive venturi effect to introduce oxygen. In any event the aim is to ensure dissolved oxygen levels of 8 ppm to 10 ppm.

[0085] Prior to operation data regarding the water system to be treated must be input in order that appropriate dosing levels of the agent are achieved. This calculation may be completed either onsite via the control system 38 or alternatively offsite at a remote server. Appropriate data such as water volume (or pool dimensions) and further may require agent concentration (optionally - but typically automatically determined). From this the volume of liquid agent to be added to the water can be determined.

[0086] The preferred concentration of the agent prior to dispensing is between 50 and 90 mg/l, even more preferably between 70 and 85 mg/l, and even more preferably approximately 80 mg/l. Such a concentration range has been found to be suitable to prevent reprecipitation of the metal compound out of solution over time, with a concentration of around 80 mg/l providing optimum results.

[0087] The agent is dosed via a dosing arrangement 4 which may be in the form of a peristaltic pump controlled by the control arrangement 38 where an initial dose is added to the water sufficient to achieve a desired concentration of 0.2 mg/l. The pump 4 is then controlled to regularly dose agent to the water dependent upon a measured concentration of agent. This can readily be measured using a colorimeter photometer, for example (not shown in the schematic diagram). Dosage of the agent can therefore be controlled accordingly.

[0088] The system according to the illustrative embodiment as presented in FIG. 1 further comprises a light emitting arrangement for emitting UV light to the water downstream of the oxygenator is present. The method may also comprise the step of applying UV light to the water. This acts as a sterilising effect and is an extra defence to the provision of the arrangement for mechanical reduction of the concentration of nutrients. The application of UV light is preferably downstream of the oxygenation step if present. The effect of UV light is to increase the photocatalytic effect of any metal oxide present in the water. In addition to UV light, the water may be treated with ozone to effect an increase in generation of disinfecting oxidising agents.

[0089] The dosing arrangement 32, such as a further peristaltic pump, is presented in the illustrative embodiment downstream of the first and second stage filter arrangements 6,7 and is provided for dosing the water with a pH controlling agent. The dosing arrangement doses a pH controlling agent such as calcium and/or magnesium carbonate in liquid form in order that the pH of the water is maintained at a preferred pH of between 7.9-8.3.

[0090] The second stage arrangement 7 may be present for additional nutrient control. The second stage arrangement 7 comprises a secondary nutrient reducing arrangement comprising a nutrient adsorbing filter, where the nutrient adsorbing filter comprises an ion exchanger such as an activated alumina or iron hydroxide filter. It will be appreciated however that although increasing the effectiveness of the system, it is not essential for the system to function.

[0091] Aspects of the present invention have been described by way of example only and it will be appreciated to the skilled addressee that modifications and variations may be made without departing from the scope of protection disclosed herein.