GB2250021A

GB2250021A - Water treatment

Info

Publication number: GB2250021A
Application number: GB9124158A
Authority: GB
Inventors: Malcolm Goodson
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-11-14
Filing date: 1991-11-14
Publication date: 1992-05-27
Also published as: GB9024800D0; GB9124158D0

Abstract

Method and apparatus for water treatment, particularly applicable to ponds, aquaria and fish farming wherein a porous material such as open cell foam is provided preferably in the form of an array of profile-cut elements defining passage ways between successive elements, whereby water can pass through the array of elements, and biological water purification can occur on a surface-treatment basis without the need for water to pass through the open cell material, with the tendency for blockage to occur which is inherent in such an approach.

Description

METHOD AND APPARATUS FOR WATER TREATMENT This invention relates to a method and apparatus for water treatment. The invention is particularly, but not exclusively, applicable to the treatment of water used in ponds, aquaria and fish farming. The invention may also be applicable to the treatment of water from other sources, such as fairly clean liquids issuing from waste water treatment plants, in which the invention might be employed to provide a "water polishing" step.

Prior proposals in relation to water treatment for ponds, aquaria, and indeed for other uses have included the use of open polymeric materials such as open-cell foam, open-fibre matting and the like. Such materials have certain useful properties in relation to water treatment since they are capable of supporting very large populations of microorganisms, and these latter provide a beneficial effect in the treatment of water containing organic and inorganic pollutants. Since the effectiveness of such microorganisms in biological purification processes is directly related to the weight of microorganisms held per unit volume of water treatment/filter material, it can be said that these materials are potentially highly effective for water treatment.

However, one of the main problems arising from the use of such materials is that, due to the relatively small size of the pores within the material (50 micrometres to 2.5 millimetres) they can quickly become blocked by the growth of the microorganisms which arises from the purification process, and also by solids contained in the liquid being treated. As a result, the flow of liquid through the opencell material is subjected to rapidly increasing resistance, and in due course the filtration/water treatment material becomes blocked and treatment ceases.

Accordingly, I have identified a need for a method and apparatus in which the potential benefits obtainable by the use of microorganisms on suitable supporting materials are obtained with a lower tendency for the resistance to water flow to increase, and indeed a reduced tendency for blockage to occur, and/or improvements in relation to one or more other matters disclosed herein, or improvements generally.

According to the invention there is provided a method and apparatus for water treatment, as defined in the accompanying claims.

The method and apparatus of the invention is applicable to the treatment of water in relation to ponds, aquaria, and fish farms. There is provided a support medium capable of supporting microorganisms for effecting biological purification of the water in contact with the medium. The support medium may comprise an open-cell foam material, or a like material providing a relatively large surface area on which the microorganisms can be supported. The support medium is disposed in relation to the water to be treated so that there is provided a movement of water relative to the support medium surface in a direction extending over rather than through the support medium surface.

It can thus be seen that the method and apparatus of the invention represent a reversal of the conventional approach to the utilisation of open cell and other porous materials.

Thus, previously proposed approaches to the use of these materials provide for the water to pass through the pores of the material thus leading to relatively rapid blockage. The invention, by providing for the water flow to pass over the surface of the material, and particularly through passageways, openings or gaps provided in the body of a water treatment element, the surface water treatment effect offered by these open pore materials is maintained in combination with greatly enhanced resistance to blocking.

As a result of the movement of the water relative to the support medium in a direction extending over the surface thereof, rather than through the body of the support medium, the tendency for blockage to occur is substantially eliminated. In the case where the support medium is arranged in the form of an array of two or more elements cut or otherwise constructed from the support medium, the flow of water passes between the support medium elements, through gaps or profiled passageways defined between the elements. The elements may be cut or otherwise formed with profiles so as to maximise the surface area between the support medium elements.By appropriately spacing these apart, the water can be caused to pass in close proximity to the microorganisms supported on these surfaces, while nevertheless almost entirely avoiding the possibility of blockage of the passages therebetween, due to the relatively larger size of these, as compared with the pore size of the open-cell material itself.

In a preferred embodiment, the flow of water relative to the support medium elements passes between these elements, formed of the open-cell foam material. The water flow passes over a profiled surface of the support medium elements.

In one embodiment, the support medium elements are mounted in a fixed position and the water is caused to flow over and between these elements. In a further preferred embodiment, the support medium elements are mounted so as to be capable of movement, for example rotation, relative to a comparatively fixed body of water, so that the relative motion therebetween is nevertheless generated.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which : Fig 1 shows, diagrammatically, a side elevation view of an uncut sheet of open-cell foam material; Fig 2 shows the foam sheet of Fig 1 after being profile cut; Fig 3 shows the profile cut material (one half of the sheet) separated; Fig 4 shows the elements of the sheet material rearranged in an assembly in which the flat side faces are disposed facing the profile-cut surfaces, so as to define fluid-flow channels therebetween; Fig 5 shows an assembly of the profile cut support medium elements providing a water treatment assembly in cooperation with a air pump;; and Fig 6 shows an alternative arrangement in which the elements of the support medium, profile-cut, are mounted on a shaft for rotation relative to the water.

As shown in Figs 1 to 4, a block of support medium 10 comprising a polymeric open-cell foam is profile-cut as indicated in Fig 2 at 12. The profiling can be single or two-dimensional.

Fig 3 shows the lower of the elements 14, 16 thusformed, in which peaks 18 alternate with troughs 20 so as to increase the available surface area of the profile-cut elements.

A series of such profile-cut elements 14 are disposed, as shown in Fig 4, with their planar faces 22 disposed so as to face their profile-cut surfaces 24. In this way, passageways are defined therebetween in the fluid-flow zones 26.

The assembly of elements 14 can be provided with extra rigidity by securing the elements together by adhesive at the locations 28 where the peaks 18 meet the planar faces 22.

It will -be understood that with the assembly of elements as shown in Fig 4, the flow of liquid may be either in a single plane and direction (if the profilecutting is in one plane only), or in multiple directions in a single plane (where the profile-cutting is in two planes).

Figs 5 and 6 illustrate the use of an assembly of the support medium elements.

Fig 5 shows a pack 30 of the elements, constructed as described above in relation to Fig 4. The assembly 30 is mounted in-a tank 32 incorporating water flow/recirculation means 34 to produce the indicated flow 36 of water through the pack 30, and then round the pack for re-entry at 38 to effect further treatment.

Fig 6 shows a modification in which the pack 40 of porous elements is mounted on a shaft 42 for rotation by a motor 44 so that the relative movement between the elements and the water 46 is produced by the shaft's rotation.

During use of the above embodiments, the microorganisms progressively grow on the surface of the support medium elements, thereby providing the biological water purification capacity. This is an automatic process.

Some few days running into a few weeks may be needed for the microorganisms to reach their maximum potential for water purification. However, once this has been reached, the potential for water treatment is then maintained during use since the susceptibility of the assembly to blockage, as compared with the prior use of the materials in which the water flow was through the pores of the material, is almost entirely eliminated.

Amongst other modifications which could be made in the above embodiments while remaining within the scope of the invention are the following. Firstly, modifications of the pore size of the material and the height/depth of the profiles cut therein, such modifications being desirable to correspond with the degree of impurity in the water to be treated. Many possibilities arise in relation to the actual shape of the profiles to be cut, including, for example egg box patterns, which are perfectly suitable.

Some benefits of the invention might be available by cutting an assembly of two or more sheets or elements of the bonded porous material to form porous pads which can be used as a non-clog random-pack water treatment medium.

Claims

CLAIMS:~

1 A method of water treatment comprising a) providing a support medium capable of supporting microorganisms for effecting biological purification of the water in contact with the medium; and b) said support medium comprising an open cell material, or a like porous material providing a relatively (as compared with non-porous material) large surface area on which microorganisms can be supported; characterised by c) said support medium being disposed in relation to the water to be treated so that there is produced a movement of water relative to the support medium surface in a direction extending over rather than through the support medium surface.

2 A method of water treatment comprising providing a porous support medium for microorganisms and disposing the support medium in relation to the water to be treated so that water moves over rather than through the support medium surface.

3 A method according to claim 1 or claim 2 characterised by the water passing through openings or gaps or passageways formed in a body of said support medium.

4 A method according to any one of claims 1 to 3 characterised by producing said water movement by producing water flow relative to said support medium.

5 A method according to any one of claims 1 to 4 characterised by producing said water movement by moving said support medium relative to the water.

6 A method according to claim 5 characterised by producing said water movement by rotating said support medium relative to the water.

7 A method of water treatment substantially as described herein with reference to the accompanying drawings.

8 Apparatus for water treatment comprising : a) a support medium capable of supporting microorganisms for effecting biological purification of the water in contact with the medium; and b) said support medium comprising an open cell material, or a like porous material providing a relatively (as compared with non-porous material) large surface area on which microorganisms can be supported; characterised by c) said support medium being disposed in relation to the water to be treated so that, in use, there is produced a movement of water relative to the support medium surface in a direction extending over rather than through the support medium surface.

9 Apparatus for water treatment comprising a porous support medium for microorganisms characterised by means for producing a movement of water over rather than through said support medium surface.

10 Apparatus according to claim 8 or claim 9 characterised by the provision of openings of gaps or passageways formed in the body of said support medium.

11 Apparatus according to any one of claims 8 to 10 characterised by said support medium comprising an array of elements of said porous material.

12 Apparatus according to claim 11 characterised by said elements defining gaps or profiled passageways between successive ones of said elements.

13 Apparatus according to claim 11 or claim 12 characterised by said elements being formed with profiles to define said gaps or passageways.

14 Apparatus according to any one of claims 11 to 13 characterised by said elements being spaced apart.

15 Apparatus according to any one of claims 8 to 14 characterised by said support medium comprising open cell foam material.

16 Apparatus according to claim 15 characterised by said open cell foam material being formed with a profiled surface.

17 Apparatus according to claim 16 characterised by said open cell foam material being profile-cut in one plane.

18 Apparatus according to any one of claims 8 to 17 characterised by said open said foam material being profile cut in two planes.

19 Apparatus according to any one of claims 16 to 18 characterised by said elements of open cell foam material being secured together by adhesive at the peaks of said profile surfaces.

20 Water treatment apparatus comprising apparatus according to any one of claims 8 to 19 in combination with means for producing said water movement by moving the water relative to the said support medium.

21 Apparatus according to any one of claims 8 to 19 in combination with means for producing said water movement relative to said porous material by moving said support medium relative to the water.

22 Apparatus according to claim 21 characterised bymeans for rotating said support medium relative to said water.

23 Apparatus for water treatment substantially as described herein with reference to and as shown in the accompanying drawings.