AP124A - Filter device. - Google Patents
Filter device. Download PDFInfo
- Publication number
- AP124A AP124A APAP/P/1989/000140A AP8900140A AP124A AP 124 A AP124 A AP 124A AP 8900140 A AP8900140 A AP 8900140A AP 124 A AP124 A AP 124A
- Authority
- AP
- ARIPO
- Prior art keywords
- water
- filter device
- bacteria
- permeable material
- filter
- Prior art date
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 36
- 239000000463 material Substances 0.000 claims description 43
- 241000894006 Bacteria Species 0.000 claims description 24
- 239000004576 sand Substances 0.000 claims description 17
- 239000011148 porous material Substances 0.000 claims description 9
- 244000005700 microbiome Species 0.000 claims description 7
- 229920001282 polysaccharide Polymers 0.000 claims description 5
- 239000005017 polysaccharide Substances 0.000 claims description 5
- 241000282414 Homo sapiens Species 0.000 claims description 3
- 239000011521 glass Substances 0.000 claims description 2
- 239000011121 hardwood Substances 0.000 claims description 2
- 238000000746 purification Methods 0.000 claims description 2
- 229910052902 vermiculite Inorganic materials 0.000 claims description 2
- 235000019354 vermiculite Nutrition 0.000 claims description 2
- 239000010455 vermiculite Substances 0.000 claims description 2
- 210000002268 wool Anatomy 0.000 claims description 2
- -1 pearllte Substances 0.000 claims 1
- 229910001220 stainless steel Inorganic materials 0.000 claims 1
- 239000002759 woven fabric Substances 0.000 claims 1
- 239000002609 medium Substances 0.000 description 19
- 239000000047 product Substances 0.000 description 7
- 238000000034 method Methods 0.000 description 5
- 235000015097 nutrients Nutrition 0.000 description 5
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 description 4
- 235000012206 bottled water Nutrition 0.000 description 4
- 239000003651 drinking water Substances 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 239000008103 glucose Substances 0.000 description 4
- 238000011534 incubation Methods 0.000 description 4
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 3
- 230000001580 bacterial effect Effects 0.000 description 3
- 238000004108 freeze drying Methods 0.000 description 3
- 239000002054 inoculum Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000007420 reactivation Effects 0.000 description 3
- 229920001817 Agar Polymers 0.000 description 2
- 101100085603 Drosophila melanogaster nclb gene Proteins 0.000 description 2
- 241000589516 Pseudomonas Species 0.000 description 2
- 239000008272 agar Substances 0.000 description 2
- 239000000645 desinfectant Substances 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 150000004676 glycans Chemical class 0.000 description 2
- 230000002706 hydrostatic effect Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000000813 microbial effect Effects 0.000 description 2
- MHWLWQUZZRMNGJ-UHFFFAOYSA-N nalidixic acid Chemical compound C1=C(C)N=C2N(CC)C=C(C(O)=O)C(=O)C2=C1 MHWLWQUZZRMNGJ-UHFFFAOYSA-N 0.000 description 2
- 229960000210 nalidixic acid Drugs 0.000 description 2
- 231100000252 nontoxic Toxicity 0.000 description 2
- 230000003000 nontoxic effect Effects 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 238000009287 sand filtration Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- FHVDTGUDJYJELY-UHFFFAOYSA-N 6-{[2-carboxy-4,5-dihydroxy-6-(phosphanyloxy)oxan-3-yl]oxy}-4,5-dihydroxy-3-phosphanyloxane-2-carboxylic acid Chemical compound O1C(C(O)=O)C(P)C(O)C(O)C1OC1C(C(O)=O)OC(OP)C(O)C1O FHVDTGUDJYJELY-UHFFFAOYSA-N 0.000 description 1
- 241000590020 Achromobacter Species 0.000 description 1
- 229920000742 Cotton Polymers 0.000 description 1
- 241001310793 Podium Species 0.000 description 1
- 241000589774 Pseudomonas sp. Species 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 241000534944 Thia Species 0.000 description 1
- 241000589153 Zoogloea ramigera Species 0.000 description 1
- 229940072056 alginate Drugs 0.000 description 1
- 229920000615 alginic acid Polymers 0.000 description 1
- 235000010443 alginic acid Nutrition 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000000721 bacterilogical effect Effects 0.000 description 1
- 239000007975 buffered saline Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 238000003348 filter assay Methods 0.000 description 1
- 230000003311 flocculating effect Effects 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000011081 inoculation Methods 0.000 description 1
- 238000011545 laboratory measurement Methods 0.000 description 1
- 244000000010 microbial pathogen Species 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 239000006916 nutrient agar Substances 0.000 description 1
- 238000011017 operating method Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000001717 pathogenic effect Effects 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000006152 selective media Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000000859 sublimation Methods 0.000 description 1
- 230000008022 sublimation Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 125000000446 sulfanediyl group Chemical group *S* 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/10—Packings; Fillings; Grids
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/02—Aerobic processes
- C02F3/10—Packings; Fillings; Grids
- C02F3/103—Textile-type packing
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/34—Biological treatment of water, waste water, or sewage characterised by the microorganisms used
- C02F3/348—Biological treatment of water, waste water, or sewage characterised by the microorganisms used characterised by the way or the form in which the microorganisms are added or dosed
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Microbiology (AREA)
- Biodiversity & Conservation Biology (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Filtering Materials (AREA)
- Biological Treatment Of Waste Water (AREA)
Abstract
A filter device for use in the treatment of water
Description
Filter Device
Ihe present Invention is a filter device for the treatment o£ water to render it potable and is of particular value in emergency situations where microbiologically safe water is refcjulred with the minimum of delay and where disinfecting agents are not readily or continuously available/ or acceptable.
Nearly all water-treatment plants include as an essential feature the filtration of the available water through sand.
The two main types of sard filtration process axe described re epee Lively as slow and rapid sand filtration, which names reflect the relative rates of flow of the aqueous liquid through the filter medium. However, these two types of sand filtration process are also distinguished by fundamental differences of operating procedure,
In the case of rapid sand filters, the water is treated to coagulate the finely-divided and suspended inpurities (including many of the harmful micro-organisms present) in flocculating tanks, after which the large particles formed by coagulation are removed in settlement tanks. Pretreatment of the water in this way makes it possible to carry Out the filtration through sand at a faster flow-rate. No such prfetxeatment is carried out in the case of slow sand filters.
•v
APO00124 in slow sand filters, removal of impurities, and particularly harmful jnicroorganlsnvs, is effected not only by physical straining through the upper layers of the surd grains, bwf also by the entrapment of the impurities by microorganisms which develop in the upper layer of the sand: thio is conn-only known as the Sdmutadecke* layer/ which initially may take several weeks to develop and in the slow sand filter plays a key role in producing a high quality water.
In an emergency situation in which supplies of safe potable water need to be established and wherein sources of chemical treatment agents such as disinfectants are not readily available, it would in principle be desirable to use a slow sand filter for the purpose. However the creation of the necessary Schmut.zdecke layer takes such a long time that slow sand filters have until noV been wholly unsuitable for use in an emergency.
Against this background, it is an object of the present invention to provide a filter device which i3 of value in emergencies and other situations and which may be used to establish supplies of safe water in a matter of hours.
The filter device according to the present invention comprises exo-polysaccharide producing, gram-negative tec ter la supported upon a water-permeable material which is non-toxic tp microorganisms and to human beings, is resistant to temperatures within the range from -15°C to <65Ο<2, and i« not readily biodegradable. This novel filter device, which may h>e used as a replacement in a slow sand filter for the conventional Scbnutzdecke layer, is available for producing potable water in
A fraction of the time which would be required for the creation ofc a usual Schnutzdecke layer.
In one preferred fom of the filter device according to the present invention, the device is freeze-dried after the bdcterla have been applied to the water-penreable material.
The freeze-dried product may then be vacuun packed so as to exclude moisture and stored until required for use. When an emergency arises in which potable water is required urgently, the product may be reactivated within a few hours by the addition of water and then be used, suitably supported, for thie purification of available water in the manner of a slow safrd filter.
The exo-polysaccharide producing, gram-negative bacteria employed in the filter device of the invention are of a type which is found in Setmutzdocke layers; that is, they occur naturally in the biofilm layer of a standard slov-sand water fitter, especially in the region within 5 an, more especially
I
2.5 cm, of the surface of the filter medium. Sudh naturally-1 ooCurring bacteria are characteristically producers of ooplous amounts of polysaccharides In the form of a viscous or gelatinous material, under conditions of lew nutrient concentrations. The bacteria used in the present invention may be a mixture of bacteria obtained as such from a Schmutz<iecke layer or may be pjte cultures of single strains of a bacterium vised singly or in mixtures. Among suitable bacteria may be mentioned strains of pseudomonas vesiculdris, for example NCIB4O121; zoogloea ramigera, for exanple ATCC 25935 OV NClB 10340; pseudomonas sp. ,
AP 0 0 0 1 2 4 bad original fbY example NCIB 11264; achromobacter georgiopolitanum j for ex^nple ATOC 23203; and non-pathogenic alginate-producing pseudomonads such as pseudomonas mendoclna, for example NCTA 10541.
The particularly preferred bacterium for use in the filter device according to the present invention is that which Is part of the dominant microbial flora in the surface bib film of an established conventional slow sand filter and which is deposited as NCIB 40121. It has the following properties, nemely unpigmented rapid growth on Msdivm A (sbe below), copious polysaccharide slime production on Medium B (see below) both in liquid medium and on medium solidified with 1.5 per cent agar, no or very poor growth on full strength standard bacteriological Nutrient Agar media, and no growth on McGonkey Agar. In the foregoing and hereinafter,
Madium A is the product Nutrient Broth of M~Lab Ltd., at a * « concentration of 2.5g/litre, containing l.Og/lltre of glucose. Medina B is Nutrient Broth at a concentration of 2,5g/litre containing lO.Og/litre of glucose.
The selected bacterium or mixture of bacteria is supported up}n a water-permeable material of the characteristics specified above. The material employed should be not readily biodegradable bi£ material which biodegrades relatively slowly, for example ovdr the period of use of the device, which may typically be say from 3 to 6 months, is suitable for this purpose. Preferably the material is resistant to ultraviolet radiation, to enable it bo oe used in conditions of prolonged strong sunlight. In order
Λ
to permit the colonisation of nvLcroorganiima on its surface, it is desirable that the surface of the material should be not highly polished ror smooth. Of oourse the selected wate.rpeimeahle material should be of low solubility, or insoluble, irt aqueous liquids.
The water-permeable material may take various forms.
Thus, for example, it may be a rigid or compressible porous material such as an expanded polymeric material, or a fibrous mat such as of coir, or a non-wven fabric such as a paper-like product, or a woven product such as of cotton or of a cellulosic material. A suitable expanded material Is the cellulosic sponge sdld under the trade nark Spontex (of Spontex Ltd,). Wien a flexible material of this type is used, it may be stored and/or ootaveyed in rolled and/or oonpressed form, a suitable non-woven material is the product sold under the trade mark Vilene, vhich is offered for sale as a tailor’s interfacing material. Thin sheet materials such as Vilene may be used in single or ntfltiplo layers, or sandwiched with other materials for support.
if the selected water-permeable material ig porous it should, of course, be open-pored. The average pore diarreter is preferably at least 10 microns both before and after in^regnation with tJie bacteria, tbre preferably, the average pore diameter is at least 20 microns, especially of the order of 50 microns, before impregnation. Both the pore diameter aril the pore density affect the rafe at which the water to be purified can pass through the filter device and this should be tome in mind in selecting the water-permeable material to
BAD ORIGINAL
AP 0 0 0 1 2 4
-fibs used. With thia in mind, porosities of 70 to 90 percent and higher are preferred.
If the filter device is to be freeze-dried, then conditions typical for freeze-drying processes may be used for that purpose. Preferably the iitpregnated material is frozen at a tdnperaturs of the order of minus 70 degrees Centigrade or ldVasr. The subsequent removal of water by sublimation under vacuum is preferably carried out under a vacuum of 1 torr or below that pressure. Following freeze-drying, the impregnated material is sealed in any suitable material which is inpenreahle to water-vapour, for example a sheet synthetic polymeric material. Wien the freeze-dried product is subsequently required for uso, the vacuum seal is broken and water is added, with the resul t thAt within several hours (for example 6 to 8 hours) the microorganisms are reactivated and ready for use. To promote «
reactivation and growth of the freeze-dried microorganisms, microbial nutrients may ba incorporated in the impregnated material before the freeze-drying step,or may be added to the water used for reactivation.
In order to use the filter device according to the invention, it may be placed in contact with a bed of sand or another filter support medium and then the water to be purified is passed throujh the device and the filter support medium in tutn. Ebr example, the device may be laid horizontally upon a ted of sard or attached in a vertical position to one or rove blocks of a rigid porous support medium. Suitable simple structures for this purpose are shown in the attached drawings,
BAD origin*1-7wherein :Fig, 1 le a vertical sectional elevation Of a first form of filter unit;
Fig. 2 is a plan view corresponding to 5 Fig, 1;
Fig. 3 is a vertical sectional elevation of a second form of filter unit; and
Fig. 4 J.e a plan view corresponding to Fig. 3.
IO The filter unit illustrated in Figs. 1 and 2 is, as shown, s<juare in plan (for example approximately 1 metre square) ard somewhat taller than it is wide (say about 1,5 metres). It is formed of flanged flat tank sections made in glass-reinforced plastic, assembled in situ from a readily transportable pack, upon a support plinth 10. Within the lower part of the unit defined by side sections 11 are underdrains 12 of gravel or «
el/nilar material and above the underdrains 12 is a support medium 13 of sand.
A filter device 14 according to the Invention in the form of a bacterial layer on a flexible water-inpermeable material is supported by the medium 13. The edges of the device 14 are held and sealed between the flanges of the side sections 11 and upper side sections 15. The level of water 16 in' the unit is controlled by an overflow 17.
In use of the unit, water for treatment is introduced to the upper part of the tank by an inlet pipe 18 and percolates through the filter device 14 and the support podium 13 to the
AP000124
BAD OR'Q^M.
uriderdrains 12, potable water being withdrawn via a valvod outlet pipe 19. When, In use, the filter device 14 eventually becomes blocked/ it is readily replaced by a new one.
The' unit illustrated in Figs. 3 and 4 relies upon vertical 5 filter panels, through which the water flows in a generally horizontal direction from an Inlet 20 to an outlet 21, the water level being controlled by an overflow 22. The filtering system consists of filter devices 23 according to the invention, Attached at their edges to blocks 24 of a porous support medium, placed at spaced positions vertically in the water tank.
In the case of the unit of Figs. 3 and 4, when a filter device eventually becomes blocked, it and the associated support block 24 nay easily be replaced without the need to take the unit overall out of service.
In experimental use of each of the illustrated units, hi£h removals of pathogenic microorganisms have been achieved within hours of the initiation of the reactivation of the supported bacteria.
The invention is further described and illustrated by meins of the following Examples, which describe the preparation of two embodiments of the filter device according to the indention and the use of one of the resulting devices to pdbify contaminated water. In both cases, the bacterium used wa& the particularly preferred bacterium described above and identified by the Deposit No. NClB 40121.
Example 1
Ohe Maintenance Medium is the above-described Medium 0
BADORieiNA^ solidified with J.5 per cent (w/v)agor. For long-tern storage, bacteria grovn on Maintenance Medium at 3o°C for 48 hours are suspended in Median B containing glycerol (20% w/v) &nd stored at - 70°C in screw-carved bottles. Γη nil cases the glucose, sterilised separately by autoclaving at 121°C for 15 min, Is added after the medium has been sterilised in the same way.
(a) Growth of inoculum.
The si lire-producing bacterium is inoculated from a maintenance plate into 5Gml Median A in a 25Onl capacity cofiical flask and incubated in a shaker-incubator at lOOrpn,
3cfic for 16 hours. This culture is used to inoculate (2% vol/vol) 5Onl of the same medium, and the culture is incuhntod ae above for 6 hours.
(b) Inoculation off water-permeable iftaterial and growth of bacteria.
Sterile discs, 5cm. diameter, of a cellulosic sponge material sold as Spontex, that has been wasted at 121°C in distilled water under pressure in an autoclave, are incubated in the above inoculum, under the same conditions, for 3 hours.
Thfe inoculated filter discs are transferred aseptically to
SOfrl of Medium B in a 25Cml capacity conical flask, and incubated at 30°C, lOOrpn, in an orbital incubator until sufficient slLny biifilm has been establlslied to provide a resistance to water flow such that a linear flow rate of approximately 0.2n/tjour .
is obtained tlaough the filter under a hydrostatic head of W,
A typical time of incubation taken to achieve this amount of biofibn will be between 8 and 16 hours depending on the initial — bad ORIGINAL ' 1 +
AP 0 0 0 1 2 4
- 10 pore size of the support material. A larger pore size predicates a longer ineulntion period.
Efrwyle 2.
The procedure described in Exanple 1 is used to establish 5 hiofilms in 5cm diameter discs of 1 to 2rrm thick layers of the non-woven fabric sold under the trade mark Vilene. a suitable blofilm was formed after 8 hours of incubation.
Bxanple 3.
By the sarpe procedure as used In Examples 1 and 2, a blofilm was formed In 5an diameter discs corrprlalng a lcmm thick layer of coir fibrous matting strengthened with plastic net. The final incubation time was 16 hours.
Example 4. ' Laboratory measurement of filter performance. Performance is assessed using 5cm diameter bio film15 impregnated discs as prepared in Exanples 1 to 3 in standard laboratory filter holders with plastic mesh support screens, under a hydrostatic head of 10cm, Two types of test water are used (a) faecal coliform-contaminated hatural water, typical ly incoming water to a municipal water treatment works; (b) phosphato20 buffered saline containing a laboratory strain of Esther ichia coil that carries a nalidix acid-resistance gene, (between 10,000 and 20,000 bacteria/lOOml). The coliform bacterial count (used as e measure of water quality) is measured irt both waters by the standard international procedures (principally the use of a selective medium ” McConkey's median - in multiple tube and filter assays, and standard confirmatory tests for E.<pli). Nalidixic acid-resistant bacterU are counted fcy plating O.lml
BAD ORIGINAL samples of the contaminated water on to Nutrient A<pr (R-Lab Ltd.) plates containing nalidixic acid at lQugA^ ·
The effluent water from the filters la assayed for coliform ocfntamlnatton as described above In successive 2Q0ml batches of filtrate. Typically Uie coliform count Is reduced to less than 10 bacteria per 100ml in the second 200ml of filtrate and remains below this level in subsequent 200ml batches (at least 10).
R^urple 5. Production on a large laboratory scale.
The water-permeable support material used is a l-fhetre-square sheet of the cellulosic sponge sold under thfe trade mark Spontex, 15 to 2Qrm thick. ibis shoot is washed in distilled water by autoclaving at 121°C for 2 hours and is subsequently squeezed dry. The sheet is fully iimersed in Medium A in a laboratory fetwsnter and sterilised with the medium, in-situ. The glucose is sterilised separately as in Example 1, end added aseptically. The fermenter tenperature in equilibrated at 3O°C and a 5% (by volume) inoculum of bacterial culture, prepared as for th$ iroculun in EXanple 1, is added. -,The fermenter is ao?ated at 1 litre air/min/litre of culture meditsn, and stirred at 200xpm. After 8 hours, sterile gluooee (40% w/v) is addod to give a final concentration of lOg/litre and incubation is continued under the same conditions for a further pefiod of between 16 and 24h. ; dissolved oxygen levels are noC controlled.
The,inpj^gnated sheet obtained is suitable for use in a
BAD OR»®114*1’
AP 0 0 0 1 2 4 filter unit such as one of the two types illustrated in thfc acoonpanylng drawings.
One erred material froift which the water-permeable layef is formed is a cellulosic sponge, a£ disclosed herein. However, other materials may be used, provided they meet the major requirements of being: (a) water permeable; (b) non-toxic to micro-organisms and to human beings; <c) resistant to temperatures within the range from -15°£ to +65°C; and, (d) not readily biodegradable.
The further materials which may be employed in a filtfer device of the invention, to support the exopolypaccharide producing gram-negative bacteria, may be self*-supportlng, or carried on or in a suitable support. Examples of these further materials include sand / gravel, staihless steel wire wool, sintered glass, vermiculite, pearlite. and hardwood sawdust or shavings.
bad original
Claims (12)
1. A filter device fbr use in the purification of water, characterised in that it comprises exo-polysaccharide producing, graft-negative bacteria supported upon a water-permeable material
5 which is ron-toxic bo microorganisms and to human beings, is resistant to benperatures within the range from -15°C bo +65°C, and is not readily biodegradable.
2. A filter device according bo claim. 1, characterised in that the bacteria are of a type occurring naturally in the
10 biofilm layer of a slo'W'-sand water filter,
3. A filter device aooording to claim 1 or claim 2, characterised in that the bacteria are one or more of the bacteria identified by the Deposit Nos. NCIB 40121, ATOC 25935, NCIB 10340, NCIB 11264, ATCC 23203 and NCIB 10541.
15
4. A filter device according to any of the preceding claims, characterised in that the water-pemeable material is a rigid or compressible porous material.
5. A filter device according to claim 4, characterised in that the weter-peiToeable material is a cellulosic sponge.
20
6. A filter device according to claim 4 or claim 5, characterised in that the water-perroeahle material has an average pore diameter of at least 20 microns,
APO 0012 4 bad original
2/2
7. A filter device according to any of claims 4 to 6, characterised in that the water-permeable material has a porbsity of at least 70 per cent,
8. A filter device according to any of claims 1 to 3,
5 characterised in that the water-permeable material is a fibrous mat.
9. A filter device according to claim 8, characterised in that the fibrous mat comprises ooir fibres.
10. A filter device according to any of claims 1 to 3,
10 characterised in that the water-permeable material is a non-woven . or woven fabric.
11. A filter device according to any of the preceding claims, characterised in that it has been freeze-dried after the bacteria have been applied to the water- permeable material.
12. A filter device according to any one of Claims 1 to 3. 6. 7. or 11. in which the water-permeable material comprises sand / gravel, stainless steel wire wool, sintered glass, vermiculite, pearllte, or hardwood sawdust or Shavings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| APAP/P/1989/000140A AP124A (en) | 1989-09-25 | 1989-09-25 | Filter device. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| APAP/P/1989/000140A AP124A (en) | 1989-09-25 | 1989-09-25 | Filter device. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| AP8900140A0 AP8900140A0 (en) | 1989-10-31 |
| AP124A true AP124A (en) | 1991-03-14 |
Family
ID=3460636
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| APAP/P/1989/000140A AP124A (en) | 1989-09-25 | 1989-09-25 | Filter device. |
Country Status (1)
| Country | Link |
|---|---|
| AP (1) | AP124A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB598956A (en) * | 1946-07-12 | 1948-03-02 | American Cyanamid Co | Improvements in containers |
| US4287057A (en) * | 1980-09-02 | 1981-09-01 | Stanley Bedford F | Portable sink top water conditioner |
| DE3413551C2 (en) * | 1983-04-29 | 1988-11-24 | Akzo Gmbh, 5600 Wuppertal, De |
-
1989
- 1989-09-25 AP APAP/P/1989/000140A patent/AP124A/en active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB598956A (en) * | 1946-07-12 | 1948-03-02 | American Cyanamid Co | Improvements in containers |
| US4287057A (en) * | 1980-09-02 | 1981-09-01 | Stanley Bedford F | Portable sink top water conditioner |
| DE3413551C2 (en) * | 1983-04-29 | 1988-11-24 | Akzo Gmbh, 5600 Wuppertal, De |
Also Published As
| Publication number | Publication date |
|---|---|
| AP8900140A0 (en) | 1989-10-31 |
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