GB1563306A - Process and a device for purifying water - Google Patents
Process and a device for purifying water Download PDFInfo
- Publication number
- GB1563306A GB1563306A GB35305/76A GB3530576A GB1563306A GB 1563306 A GB1563306 A GB 1563306A GB 35305/76 A GB35305/76 A GB 35305/76A GB 3530576 A GB3530576 A GB 3530576A GB 1563306 A GB1563306 A GB 1563306A
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- United Kingdom
- Prior art keywords
- filter
- water
- layer
- fibres
- container
- Prior art date
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims description 83
- 238000000034 method Methods 0.000 title claims description 42
- 239000000463 material Substances 0.000 claims description 46
- 244000005700 microbiome Species 0.000 claims description 26
- 239000007788 liquid Substances 0.000 claims description 21
- 239000000835 fiber Substances 0.000 claims description 20
- 239000011490 mineral wool Substances 0.000 claims description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 10
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 9
- 230000000694 effects Effects 0.000 claims description 9
- 239000012535 impurity Substances 0.000 claims description 9
- 229910052760 oxygen Inorganic materials 0.000 claims description 9
- 239000001301 oxygen Substances 0.000 claims description 9
- 241000251468 Actinopterygii Species 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 239000000126 substance Substances 0.000 claims description 6
- 230000009182 swimming Effects 0.000 claims description 6
- 229910052681 coesite Inorganic materials 0.000 claims description 5
- 230000006835 compression Effects 0.000 claims description 5
- 238000007906 compression Methods 0.000 claims description 5
- 229910052906 cristobalite Inorganic materials 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 5
- 238000000746 purification Methods 0.000 claims description 5
- 239000000377 silicon dioxide Substances 0.000 claims description 5
- 235000012239 silicon dioxide Nutrition 0.000 claims description 5
- 229910052682 stishovite Inorganic materials 0.000 claims description 5
- 229910052905 tridymite Inorganic materials 0.000 claims description 5
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 claims description 4
- 238000011001 backwashing Methods 0.000 claims description 4
- 239000003651 drinking water Substances 0.000 claims description 4
- 235000020188 drinking water Nutrition 0.000 claims description 4
- 244000045947 parasite Species 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 4
- 241000894006 Bacteria Species 0.000 claims description 3
- 239000000470 constituent Substances 0.000 claims description 3
- 229910044991 metal oxide Inorganic materials 0.000 claims description 3
- 150000004706 metal oxides Chemical class 0.000 claims description 3
- 239000011368 organic material Substances 0.000 claims description 3
- 230000001717 pathogenic effect Effects 0.000 claims description 3
- 241000242678 Schistosoma Species 0.000 claims description 2
- 239000003795 chemical substances by application Substances 0.000 claims description 2
- 235000013601 eggs Nutrition 0.000 claims description 2
- 244000000010 microbial pathogen Species 0.000 claims description 2
- 230000003472 neutralizing effect Effects 0.000 claims description 2
- 235000015097 nutrients Nutrition 0.000 claims description 2
- 230000003071 parasitic effect Effects 0.000 claims description 2
- 238000005192 partition Methods 0.000 claims description 2
- 239000003643 water by type Substances 0.000 claims description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 4
- 241001465754 Metazoa Species 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 238000006731 degradation reaction Methods 0.000 description 3
- 239000000155 melt Substances 0.000 description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- -1 stone-wool Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 102000004190 Enzymes Human genes 0.000 description 1
- 108090000790 Enzymes Proteins 0.000 description 1
- 241000282414 Homo sapiens Species 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 230000001154 acute effect Effects 0.000 description 1
- 244000052616 bacterial pathogen Species 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000011491 glass wool Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- VASIZKWUTCETSD-UHFFFAOYSA-N manganese(II) oxide Inorganic materials [Mn]=O VASIZKWUTCETSD-UHFFFAOYSA-N 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000011785 micronutrient Substances 0.000 description 1
- 235000013369 micronutrients Nutrition 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000008213 purified water Substances 0.000 description 1
- 239000011435 rock Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 229910001415 sodium ion Inorganic materials 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
- A01K63/00—Receptacles for live fish, e.g. aquaria; Terraria
- A01K63/04—Arrangements for treating water specially adapted to receptacles for live fish
- A01K63/045—Filters for aquaria
-
- 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
- C02F3/06—Aerobic processes using submerged filters
-
- 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
-
- 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)
- Biodiversity & Conservation Biology (AREA)
- Water Supply & Treatment (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Microbiology (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Environmental Sciences (AREA)
- Marine Sciences & Fisheries (AREA)
- Animal Husbandry (AREA)
- Filtering Materials (AREA)
- Biological Treatment Of Waste Water (AREA)
Description
(54) A PROCESS AND A DEVICE FOR PURIFYING WATER
(71) 1, AKE 0. V. HELLQVIST, a Swedish subject, of 130 40 Djurhamn,
Sweden, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following state menu: This invention is related to a process and a device for purifying water by removing micro-organisms which make it possible to remove and make harmless micro-organisms smaller than 10 microns as well as larger micro-organisms and especially within the range 10-100 microns.
A method according to the invention comprises purifying water containing oxygen by removing micro-organisms by passing the water through a mineral wool, e.g. glass wool, or, especially, a so-called rock-wool, stone-wool, slag-wool or similar mineral wool materials.
A device according to the invention comprises a container containing a filter comprising mineral wool, an inlet for water to be passed through the filer and an outlet for purified water.
The filter material is preferably produced by forming fibres of a melt, e.g. by pouring the melt onto a rotating disc or a similar device.
The fibre material should comprise a considerable and preferably a preponderant part and especially to at least 90% consist of fibres with a diameter below 15 microns.
A suitable fibre diameter is about 1-5 microns. Suitably at least 90% of the total fibre length has a diameter within said range. A suitable average fibre length is up to 10 mms, preferably 1-5 mms., such as 1.5-2.5 mms but also shorter or longer fibres may be used.
The fibses should mainly be arranged randomly in three directions, i.e. in space.
The fibres should comprise at most 20% preferably at most 10% and especially at most 5% of the volume of the fibre material, the rest of the volume consisting of a void interspace and optionally some further constituent, such as a binder or a similar material, in a quantity which preferably does not exceed the volume of the fibre's solid. Preferably a binder content below 5-1061O, e.g. 1-2'0/01 is used.
The fibres are preferably arranged randomly and mainly without binder for mutual bonding of the separate fibres. Such a binder can, however, also be used provided that it does not essentially decrease the efficiency of the filter material for purifying water.
A suitable fibre solids content is about 3% by volume.
The fibre material should also be completely wettable with water and should maintain the original shape when saturated with or soaked in water.
It is preferable to use a fibre material which in the treated liquid exhibits a Zetapotential which is essentially 0 or slightly negative, i.e. slightly cation-active, preferably to a maximum of - 50 mV.
A suitable fibre material is a material prepared from rock minerals, such as diabase and lime. A suitable weight ratio of mineral, especially diabase to lime, is about 80/20. Furthermore, coke is normally used when preparing the melt from which the fibres are prepared.
A suitable composition of the filter material is:
40-60% SiO2 10-20 fo Al2Oa 1()-20to CaO
5-15% MgO
Balance other metal oxides such as FeO, Na2O, TiO2, MnO, KoO.
An example of a composition is:
47% SiO.
14% A1203 16% CaO 10% MgO 8% FeO 2% Na2O lto TiO2
1% MaO
1% K2O These values may vary about 10%. This material exhibits a low level of sodium ion solubility and an equilibrium pH in water which is close to the neutral.
The process according to the invention can be used generally for purifying water, e.g. for purifying raw or untreated water, preferably after a treatment for removing impurities by flocking, for sewage purification. especially after so-called three stage purification, for removing suspended substances and remaining flocked materials and also for a number of other aqueous liquids with a low content of organic materials as defined more extensively below. The water treatment may also comprise filtration to remove calcium, magnesium or iron hardness.
By the invention it is possible to remove micro-organisms below 10 microns in size.
Thus, the process is efficient for removing bacteria and similar microbes, especially pathogenic bacteria. The mechanism by which said micro-organisms are removed can be postulated to depend on the build-up of a biological layer or film in the filter material, in which unwanted microorganisms are consumed by other microorganisms (e.g. protozoon) and degradation by a biological oxidation process. For said purpose the water is oxygenated to a suitable degree before it is passed into contact with the filter, or by introducing oxygen or air into the filter material through absorption in a so-called trickle filter.
Preferably therefore a biological layer is maintained m the filter and the flow rate is so selected that it is sufficient for maintaining the activity of the layer and for preventing clogging of the filter, for instance by continuous degradation of the separated micro-organisms in the biological layer.
The filter material may comprise a supply of nutrient agents, especially potassium, phosphorus nigrogen, micro nutrient salts or enzymes, in a form such that they are available to micro-organisms in the filter for an extended time of use, e.g. 1 month or preferably 1 year.
The method according to the invention is also highly suited for simultaneously removing micro - organisms above 10 microns in size and preferably with a size between 10 and 100 microns or more.
Such micro-organisms may e.g. consist of protozoons which are pathogenic for animals or human beings.
The reason why the method and the filter material according to the invention are so surprisingly efficient is not known with certainty. It is, however, probable that the efficiency of the process and material depends on a combination of a number of cooperating effects, especially that the fibre material by a suitable Zeta potential in the liquid and/or by chemical structure and/or surface structure tends to improve the addition and accumulation of microorganisms on th surface of the fibres. A random arrangeil ent of the fibres in essentially three directions or dimensions may also improve and contribute to this effect in that the fibres may act as mechanical traps for suspended particles or microorganisms of various size ranges.
These cooperating effects lead to the result that it is possible to use according to the invention a very high flow rate in metres per hour (m;/m2.h). Thus, the area load or load per filter area unit may be maintained above about 1-1.5 metres per hour and up to 3-5 metres per hour or higher, and is preferably 10 metres per hour or higher, without sacrifying the efficiency. This high load capacity of the material can be expected to depend on a combination of several factors, e.g. the good mechanical shape stability in water also when the water is streaming through the filter material which will have the result that the filter material maintains a loose structure which can easily be penetrated by the liquid. In spite of said high load capacity the material has a very good capacity for removing the micro-organisms mentioned above which are continuously picked up and degraded or decomposed in the filter material without sacrafice of the load capacity.
The filter bed thickness can be selected to a very low value in combination with the
stated high load capacity values, e.g. a thickness below I metre down to 5-10 cms.
or less with maintained high separating capacity.
The impurity content in the feed material, i.e. aqueous liquid to be treated, may vary within broad limits, e.g. from 5 to 50 BOD (Biological Oxygen Demand). BOD.. is the oxygen consumpticn in mg 0 per litre liquid of a sample maintained for 7 days in the dark at 180C.
It is also preferable that the fibre material has a sufficient shape stability in the treated liquid when subjected to the flow of the treated luiquid through the filter material so that the structure of the fibre material is maintained essentially unchanged with maintained high permeability to the liquid being filtered. The compressibility at the liquid flow load, e.g. 5-10 metres / hour, may e.g. be maintained below 20cue and preferably below 10% and preferably the filter material should exhibit a compression of less than 1% and especially exhibit no compression at all at a flow rate of 5-10 metres/hour. If desired, the filter material may comprise a supporting matrix or structure, e.g. consisting of coarser fibres, which contributes to the resistance against compression of the filter material and under the influence of the liquid flow.
Preferably a cube of the filter material should after soaking in a filtered liquid and subjected to a compressive load on surfaces of the cubic piece of filter material, which are perpendicular to the intended flow direction with 1 square inch area, exhibit a compression of less than 50'my preferably less than 10to and especially less than 5% when increasing the compressive load from 10 grams to 20 grams or from 50 grams to 150 grams.
Preferably the fibre structure is randomly oriented, i.e. the filter fibres are arranged randomly in all directions in space. There may, however, be a certain degree of orientation of the fibre directions depending upon the method of production used for the fibre materials or since some special effect is desired, such as forming mechanical traps with fibres crossing each other at an acute angle, especially with a preponderant orientation of the fibres in the direction of the liquid flow.
It is also possible to arrange the fibres preponderantly perpendicular to the direction of flow, e.g. with the fibres mainly oriented in a plane perpendicular to the direction of flow.
The filter may also be composed of a number of layers of the same kind of material or of various kinds of filter materials. The filter may e.g. comprise in the direction of flow first a layer of a coarser filter material which retains coarser particles which otherwise may clog the finer filter material which is used for water purification according to the invention.
It is also preferable that the filter is shaped so that it can be removed from the treated water without permitting removed
impurities to be returned to the treated
liquid by back-washing. If the filter is submerged in a tank containing the water to be treated the inlet to the filter container is preferably connected to the outlet from the propelling or circulation means, e.g. a pump. Alternatively and especially when the filter is arranged outside a tank containing the treated water and is connected to said tank through a conduit, said conduit should have a volume which is sufficient for accommodating any back-wash or back-flow of water so that re-introduction of impurities from the filter into the water of a liquid tank is prevented.
The filter material may also comprise a first layer which is permeable to microorganisms up to 10 microns in size and preferably up to 50-100 microns in size, and a second, finer filter layer, i.e. a filter layer in which the average or maximum distance between the filter fibres is smaller so that the probability of mechanic trapping or contact between the micro-organisms and the filter fibres is increased.
The invention is especially related to a biological filter for treating aqueous liquids with a low BOD value. The BOD7 value of the treated aqueous liquid (or water) is preferably below 50 and especially below 10, e.g. between 2 and 5. According to the invention it is possible to create in the filter materials comprised by the invention an efficient biological layer which at the stated
BOD value of the treated water or aqueous liquid maintains a sufficient degree of efficiency and simultaneously is subjected to a continuous degradation so that clogging of the filter is prevented. The load on the filter may according to the invention be varied within broad limits. For optimum production capacity the flow rate may be maintained continuously, or at least periodically, above 1 metres per hour and especially above 2 metres per hour. It may be 1-1.5 metres per hour but usually is 3-5 metres per hour or more. Preferably it is at least 5 metres per hour and most preferably is 10 metres per hour or more.
The filter is preferably maintained under
aerobic conditions, i.e. the water which flows through the filter shuld have a sufficiently high oxygen content which can be achieved by aerating the water or by adding air or oxygen together with the water to the filter. Optionally also oxygen-containing compounds may be added, e.g. per-oxygen compounds.
The process according to the invention is especially suited for purifying water which is used for maintaining alive animals or plants, e.g. tanks or pools for rasing fish and aquana.
For said purposes the water is passed continuouslv or intermittently through a filter according to the invention. The water
flow through the filter can be achieved with a pump, e.g. an air lift pump, in which the water is lifted with injected compressed air. The pump and/or filter may be arranged in and/or outside the quantity of water in which it is desired to maintain living animals (including fish) and plants.
Prior to the biological filter according to the invention one may arrange a mechanical filter for removing the coarser particles, etc.
which could otherwise clog the biological filter. fhe filter according to the invention should be shaped so tLat it can be removed from the treated water without permitting removed impurities to be reintroduced into the water by back-flow or back-washing and the filter should be shaped and arranged so that any such back-flow or back-washing or liberation of micro-organisms from the filter is not obtained to an essential extent or is completely avoided if the flow of water is discontinued. The inlet to the filter should preferably be connected to the outlet of a circulation pump.
When using a filter according to the invention for purifying the water in aquaria, fish raising plants, swimming pools, drinking water, s-upply plants or for similar purposes the filter can be used for separating and neutralizing bacteria and similar small micro-organisms, such as protozoones which are parasitic or pathogenic, worm eggs, larvae, etc., which can be neutralized e.g. by mechanical trapping between the filter fibres, holding by electrical forces, such as by the influence of the Zetapotential, as well as by the activity of microorganisms which actively consume undesired constituents in the water. An example of parasites which can be efficiently removed with the filter according to the invention is the parasites Ichtyophtirius multifilius in aquaria fish and which have a size of from 50 microns up to about 500 microns depending upon the stage of evolution, and
Schistosoma organisms.
Figure 1 discloses schematically a filter device for an aquarium with an air lift pump 1 which transfers the water to a filter container 2. Said filter container comprises a filter layer 4 according to the invention of mineral wool arranged on a perforated bottom 3 and above said filter layer a removable thinner layer 5 of a coarser filter matcrial for removing coarser particles. The flowing water forms a liquid surface 6 in the filter container 2 at a certain level above the water level 7 in the aquarium and by the pressure corresponding to said liquid level difference the water in the filter container is forced through the filter layer and through the perforated bottom. The water circulating through the filter and the aquarium has a low content of organic impurities corresponding to a low BOD value and forms an active biological layer in the filter. Pathogenic microorganisms in the water are separated and destroyed in the filter by being mechanically trapped and by being attacked and destroyed in the biological layer. sgure 2 discloses an alternative embodi.nent. In an outer filter housing 8 with a water inlet and an outlet an internal filter container 9 with perforations in the bottom and the lower part the side wall is arranged. The filter material 4 and the coarser filter material 5 are arranged below a horizontal partition wall 10 with an exchangeable restriction opening insert 11 which allows only the desired maximum flow through the filter.
If the water flow to the outer housing is higher than said maximum flow the rest of the water flows over the upper edge of the inner container to the outlet as indicated with arrows.
The method is also suited for purifying water in swimming pools and similar waters.
A suitable filter layer thickness is 2-20 cms. and especially 4-10 cms. The water pressure head is preferably up to 25 cms., especially up to 10 cms. and particularly 2-5 cnfs.
WHAT I CLAIM IS:
1. A method in which water that contains oxygen is purified by removing microorganisms by passing the water through a filter comprising mineral wool.
2. A method according to claim 1 in which a biological layer is maintained in the filter through which the water is passed and the flow rate per area unit of the filter is so selected that it is sufficient for maintaining the activity of the biological layer and for preventing clogging of the filter.
3. A method according to claim 1 or claim 2 in which the water to be purified has a low content of organic materials corresponding to a BOD7 value of below 50.
4. A method according to any of the preceding claims in which the flow rate through the filter at least periodically is 5 metres per hour or above.
5. A method according to claim 4 in which the flow rate is 10 metres per hour or more.
6. A method according to any preceding claim in which the water to be purified is water from which impurities have been removed by flocking.
7. A method according to any preceding claim applied to the purification of swimming pool water, aquarium water or drinking water.
8. A method according to any preceding claim in which at least 90% of the fibres in the mineral wool have a diameter below 15 microns and a chemical composition comprising 40 to 60% SiO2, 10 to 20% A1203, 10 to 20geo CaO and 5 to I 5o MgO with the balance other metal oxides.
9. A method according to claim 8 in which the filter has a solid fibre content of up to 10% by volume and an average fibre length of up to 10 mms.
10. A method according to claim 8 or claim 9 in which at least 90% of the fibres have a diameter of from 1 to 5 microns.
11. A method according to any of claims 8 to 10 in which at least 90% of the fibres have a chemical composition, with a variation of 10%, of SiO2 47%, A1203 14%,
CaO 16%, MgO 10%, FeO 8%, Na2O 2%,
TiO, 1%, MnO 1% and K20 1%.
12. A method according to any preced
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (17)
1. A method in which water that contains oxygen is purified by removing microorganisms by passing the water through a filter comprising mineral wool.
2. A method according to claim 1 in which a biological layer is maintained in the filter through which the water is passed and the flow rate per area unit of the filter is so selected that it is sufficient for maintaining the activity of the biological layer and for preventing clogging of the filter.
3. A method according to claim 1 or claim 2 in which the water to be purified has a low content of organic materials corresponding to a BOD7 value of below 50.
4. A method according to any of the preceding claims in which the flow rate through the filter at least periodically is 5 metres per hour or above.
5. A method according to claim 4 in which the flow rate is 10 metres per hour or more.
6. A method according to any preceding claim in which the water to be purified is water from which impurities have been removed by flocking.
7. A method according to any preceding claim applied to the purification of swimming pool water, aquarium water or drinking water.
8. A method according to any preceding claim in which at least 90% of the fibres in the mineral wool have a diameter below 15 microns and a chemical composition comprising 40 to 60% SiO2, 10 to 20% A1203, 10 to 20geo CaO and 5 to I 5o MgO with the balance other metal oxides.
9. A method according to claim 8 in which the filter has a solid fibre content of up to 10% by volume and an average fibre length of up to 10 mms.
10. A method according to claim 8 or claim 9 in which at least 90% of the fibres have a diameter of from 1 to 5 microns.
11. A method according to any of claims 8 to 10 in which at least 90% of the fibres have a chemical composition, with a variation of 10%, of SiO2 47%, A1203 14%,
CaO 16%, MgO 10%, FeO 8%, Na2O 2%,
TiO, 1%, MnO 1% and K20 1%.
12. A method according to any preced
ing claim in which the filter exhibits a compression of less than 50% when soaked in water to be purified and when increasing a compressive load on a surface of a cube of the filter from 50 to 150 grams per square inch.
13. A device according to any preceding claim in which the filter exhibits a compressidn of less than 5 < 4o when soaked in the water to be purified and when increasing a compressive load on a surface of a cube of the filter from 50 to 150 grams per square inch.
14. A method according to any preceding claim m which the filter material comprises a supply of nutrient agents in a form available to micro-organisms in the filter material for an extended time of use.
15. A method according to claim 1 substantially as hereinbefore described with reference to either fiture of the accompanying drawings.
16. A device suitable for carrying out a method according to any of claims 1 to 6 and which comprises a container containing a filter comprising mineral wool, an inlet for water to be passed through the filter and an outlet for the treated water.
17. A device according to claim 16 in which the filter is as defined in any of claims 8 to 14.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB35305/76A GB1563306A (en) | 1976-08-25 | 1976-08-25 | Process and a device for purifying water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB35305/76A GB1563306A (en) | 1976-08-25 | 1976-08-25 | Process and a device for purifying water |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1563306A true GB1563306A (en) | 1980-03-26 |
Family
ID=10376213
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB35305/76A Expired GB1563306A (en) | 1976-08-25 | 1976-08-25 | Process and a device for purifying water |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB1563306A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0197213A1 (en) * | 1983-11-18 | 1986-10-15 | United Kingdom Atomic Energy Authority | Treatment of a medium for the reduction of biofouling |
| NL1000463C2 (en) * | 1995-05-31 | 1996-12-03 | Rockwool Grodan Bv | Method for the biological cleaning of water, for the substrate cultivation of plants, and a filter and a filter unit therefor. |
-
1976
- 1976-08-25 GB GB35305/76A patent/GB1563306A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0197213A1 (en) * | 1983-11-18 | 1986-10-15 | United Kingdom Atomic Energy Authority | Treatment of a medium for the reduction of biofouling |
| NL1000463C2 (en) * | 1995-05-31 | 1996-12-03 | Rockwool Grodan Bv | Method for the biological cleaning of water, for the substrate cultivation of plants, and a filter and a filter unit therefor. |
| WO1996038387A1 (en) * | 1995-05-31 | 1996-12-05 | Rockwool/Grodan B.V. | Method for biological cleaning of water, for the substrate culture of plants, and a filter and a filter unit therefor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PS | Patent sealed | ||
| PCNP | Patent ceased through non-payment of renewal fee |