GB2208164A - Purification of waters - Google Patents
Purification of waters Download PDFInfo
- Publication number
- GB2208164A GB2208164A GB8813929A GB8813929A GB2208164A GB 2208164 A GB2208164 A GB 2208164A GB 8813929 A GB8813929 A GB 8813929A GB 8813929 A GB8813929 A GB 8813929A GB 2208164 A GB2208164 A GB 2208164A
- Authority
- GB
- United Kingdom
- Prior art keywords
- water
- basic
- addition
- waters
- ferric salt
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000746 purification Methods 0.000 title claims abstract description 8
- 239000003643 water by type Substances 0.000 title abstract description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 41
- 239000008394 flocculating agent Substances 0.000 claims abstract description 24
- 150000003839 salts Chemical class 0.000 claims abstract description 21
- 238000000034 method Methods 0.000 claims description 21
- 230000008569 process Effects 0.000 claims description 15
- 239000000126 substance Substances 0.000 claims description 15
- 229910021578 Iron(III) chloride Inorganic materials 0.000 claims description 11
- 230000002378 acidificating effect Effects 0.000 claims description 11
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 claims description 11
- 238000012360 testing method Methods 0.000 claims description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 6
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 5
- 238000005189 flocculation Methods 0.000 claims description 5
- 230000016615 flocculation Effects 0.000 claims description 5
- 229910021653 sulphate ion Inorganic materials 0.000 claims description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical class OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 3
- 239000010802 sludge Substances 0.000 claims description 3
- 235000011149 sulphuric acid Nutrition 0.000 claims description 3
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 2
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 2
- 239000004571 lime Substances 0.000 claims description 2
- 235000011121 sodium hydroxide Nutrition 0.000 claims description 2
- 235000011167 hydrochloric acid Nutrition 0.000 claims 1
- 239000007788 liquid Substances 0.000 claims 1
- 239000002253 acid Substances 0.000 abstract description 5
- 239000010865 sewage Substances 0.000 abstract description 5
- 239000002699 waste material Substances 0.000 abstract description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 21
- 238000007792 addition Methods 0.000 description 11
- 239000004411 aluminium Substances 0.000 description 11
- 229910052782 aluminium Inorganic materials 0.000 description 11
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 11
- -1 hydroxyl ions Chemical class 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 6
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 5
- 239000002585 base Substances 0.000 description 5
- 239000011574 phosphorus Substances 0.000 description 4
- 229910052698 phosphorus Inorganic materials 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 150000001447 alkali salts Chemical class 0.000 description 3
- 239000001164 aluminium sulphate Substances 0.000 description 3
- 235000011128 aluminium sulphate Nutrition 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- BUACSMWVFUNQET-UHFFFAOYSA-H dialuminum;trisulfate;hydrate Chemical group O.[Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O BUACSMWVFUNQET-UHFFFAOYSA-H 0.000 description 2
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical class Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 2
- 159000000014 iron salts Chemical class 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000010801 sewage sludge Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 239000001117 sulphuric acid Substances 0.000 description 2
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 1
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 206010022528 Interactions Diseases 0.000 description 1
- 101001047513 Mus musculus Lethal(2) giant larvae protein homolog 1 Proteins 0.000 description 1
- 229920000388 Polyphosphate Polymers 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000002535 acidifier Substances 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 235000012538 ammonium bicarbonate Nutrition 0.000 description 1
- 239000001099 ammonium carbonate Substances 0.000 description 1
- 150000003868 ammonium compounds Chemical class 0.000 description 1
- 210000001691 amnion Anatomy 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- JYYOBHFYCIDXHH-UHFFFAOYSA-N carbonic acid;hydrate Chemical compound O.OC(O)=O JYYOBHFYCIDXHH-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000008119 colloidal silica Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000002509 fulvic acid Substances 0.000 description 1
- 239000003517 fume Substances 0.000 description 1
- 239000004021 humic acid Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000003295 industrial effluent Substances 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 description 1
- 150000002506 iron compounds Chemical class 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000001205 polyphosphate Substances 0.000 description 1
- 235000011176 polyphosphates Nutrition 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000012086 standard solution Substances 0.000 description 1
- 239000002351 wastewater 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
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
- C02F1/5245—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
Abstract
The purification of waste or raw waters or of sewage sludges or raw sewage by means of a basic ferric salt as a flocculating agent may be improved by control of the pH value of the water, as treated, by the addition of acid or base. Preferably the pH value is controlled within the range of greater than 5.0 to below 7.5 for example at from 5.5 to below 7.0.
Description
purification of water
This invention relates to the purification of water.
Flocculating agents are currently in very large scale use in the purification waters such as raw waters, industrial waste waters, river waters, sewage sludge or even aqueous raw sewage suspensions. The classical flocculating agent for such use is aluminium sulphate.
Others, which have been developed more recently1 are basic aluminium sulphate, basic aluminium chloride and polyaluminium chloride. The word "basic" used with reference to salts means salts in which the anionic component includes hydroxyl ions.
Flocculants based on iron compounds are known. Such flocculants are useful additions to the range of water treatment chemicals and their use avoids a high residual aluminium content in waters where this may be undesirable.
While iron-based flocculants can be extremely effective under specific conditions they do not, in general, perform as well as aluminium-based flocculants in the treatment of neutral or nearly neutral waters. Ferric chloride is an example of a widely used iron-based flocculant which is relatively ineffective, in treating waters having pH values near to neutrality. Basic ferric chloride has been proposed as a flocculating agent for water treatment but, initially, proved to be unstable especially at higher basicities in manufacture and/or storage as a concentrated solution.
production of stable basic ferric chloride has been disclosed the said method comprising the manufacture of the basic ferric chloride in the presence of a phosphorus compound.
The Applicants now provide a new or improved process for the purification of waters by means of basic ferric salts such as basic ferric sulphate or, preferably, basic ferric chloride. The Applicants have found according to the present invention that in use in the flocculation of waste or impure natural waters for example those containing colloidal silica particles giving rise to turbidity and/or humic or fulvic acids giving rise to colour, an improvement in the reduction of turbidity and/or colour may be attained by the suitable control of the pH of the water being treated. The invention is also applicable to the treatment of sewage sludhes, raw sewage suspensions or any other aqueous system requiring flocculation.
According to one aspect thereof the present invention provides a process for the purIfIcation of water or of a sewage sludge by contacting the water or sludge with an effective quantity of a flocculating agent comprising a basic ferric salt wherein the flocculation is improved by adjusting the ps of the water or sludge by the addition to the water, in addition to the basic ferric salt, of an acidic or basic substance. There are a great many normally neutral or alkaline waters which alkaline waters may, for example, have a pH value in the range 7.5 to 9.0.
In purifying such waters according to the present invention an acidic substance is added. Preferably the acidic substance is added in a quantity such that, after the addition of the flocculating agent, the pH of the water is below 7.5 but not below 5.0. It is particularly preferred that the p. of the water is from 5.25 to below 7.0 a pH range of from 5.5 to 6.5 being the optimum for the treatment of at least some alkaline waters.
There are also acidic natural or industrial effluent waters which may be purified according to the present invention by the addition of an acidic or basic substance to bring the pH to the values taught above in relating to alkaline waters after the addition of theflocculating agent. Again, the effect of the addition of the basic ferric chloride flocculating agent.
The optimum pH may vary somewhat depending on the particular water being treated and it is envisaged that the benefit of the invention may be attained by process control based on the testing of the turbidity, colour or floc development of samples of water acidified to various extents and treated with the basic ferric salt flocculating agent. The optimum pH so determined need not necessarily, although It generally wi l, lie within the preferred or particularly preferred ranges set out above.
In relation to waters tested by the Applicant, however, the optimum pH has been found to be from 5.75 to 6.25.
The use of a basic ferric salt as a flocculating agent, of course, gives, In most cases treated water having a lower residual aluminium content than the use of an aluminium based flocculating agent. It has also been found that the treatment of water according to the present invention can result an extremely low content of residual iron. This content of residual iron can be considerably lower than that in the untreated water and can at least equal the content obtainable by the use of the preferred aluminium-based flocculating agent, that is, polyaluminium chloride.
Basic ferric chloride or sulphate, for the avoidance of doubt, is understood to be a range of compounds having the general formula Fe(OH)mCl3#m, or Fe2(OH)m(SO4)3#m the % basicity being the % of Fe valency occupied by hydroxyl ions. The % basicity, for utility according to the invention, is preferably from 20% to 90% and particularly preferably from 25% to 85%. Such basic iron salts may be produced by basifying a solution of the ferric salt. The concentration of the ferric salt is preferably initIally from 2 to 20% by weight calculated as Fe203 and the pH thereof is preferably from 2.0 to 0.0. Ferric chloride or sulphate liquors having a suitable concentration and containing the corresponding acid in a quantity to give a suitable pH are available commercially.
The base utilised to produce the basic salt may be, for example, an alkali metal, preferably sodium, hydroxide carbonate or bicarbonate. Alternatively, the use of the corresponding ammonium compounds, particularly preferably ammonium bicarbonate, gives rise to particularly suitable basic ferric salts. The quantity of base may be determined by reference to the stoichiometric quantity required for reaction with the required proportion of the amnion of the ferric salt making allowance for the presence of free acid and any other substances which may react with base. The base is preferably added to the solution of the ferric salt slowly and with agItation at ambient temperature and the reaction mixture so formed is preferably aged for at least 15 minutes.If any precipitate is formed it may be removed, the residual solution of-the basic salt constituting a utilisable product. Preferably the reaction to produce the basic ferric salt is conducted in the presence of a phosphorus compound, particularly preferably a phosphate, a polyphosphate or phosphoric acid as more fully described in the aforementioned Japanese Patent Publication No. 59116127. Preferably the phosphorus compound is present in a quantity, calculated as PO4 of from 0.01 to 0.3 moles, particularly preferably from 0.025 to 0.25 moles, per atom of Fe. The effect of the present invention is particularly noticable in relation to basic ferric chloride flocculating agents containing such quantities of phosphorus compound.
In use according to the invention the basic ferric salt is preferably added to water to be treated to give a concentration of the basic salt in the water of from 1 to 50 mg.l#1 particularly preferably from 2 to 20 mg.l -l a particularly useful treatment concentration being from 3 to 15 mg.' i calculated as Foe203.
The acidic substance used to control the pH of the water to be treated according to the present invention may be any suitable acid, preferably used at an initial concentration, for example, of from 5% to 25% by weight.
Hydrochloric acid may be used although due to its tendency to fume if spilled it is not preferred on a practical usage basis. Sulphuric acid is preferred environmentally, and on a handling basis and tends to be more effective.
The basic substance used according to the present invention may very suitably be, for example, a form of lime, or caustic soda, in a similar range of preferred concentrations. It is understood however that more concentrated acid or base may be used if desire. The addition of the acidic or basic substance is preferably conducted prior to or concurrent with the addition of the basic ferric salt to the water to be treated although the benefit of the Invention may be attained, although possibly to a lesser extent, by a later or a progressive addition of the acidifying agent.
The invention will now be more specifically described by reference to the following Tests of particular embodiments thereof and to Figure 1.
Figure 1 is a three part plot of the pH of water being treated against (A) Turbidity, (B) Hazen Colour and (C) Residual Fe in the treated water. Four different flocculating agents, two according to the invention and two not according to the invention and present to provide a basis for comparison, as identified hereafter were used.
In the Tests a number of parameters are investigated.
Certain of these, for example, pH and dosage rates, and residual aluminium and iron contents require no further definition. The Tests for Colour, Turbidity and Floc size are defined below.
Colour
Measured in "Hazen" units by the technique described in "Analysis of Raw Potable and Waste Waters" published by
HMSO 1972 page 26. The technique involves the measurement of optical density at a wavelength of 400 nm using a spectrophotometer (SP600) and calibration against standard solutions.
Turbidity
Measured in FTU (Formazin turbidity units) by the technique described in the above reference on page 29.
The technique involves measurement of optical density at a wavelength of 580 nm before and after filtration through a membrane filter and calibration against formazin standards.
Floc growth
Measured on a scale of A to G, after standard addition of flocculant followed by stirring at 60 rpm, then at 20 rpm and finally allowing to settle for 30 minutes. A denotes a multiplicity of 0.3 to 0.5 mm flocs, C denotes a very few 3.0 to 4.5 mm flocs and B to F denote intermediate conditions.
In all the Tests the waters treated were input waters to existing water treatment plants, not artificially produced systems, e.g. suspensions of clays. The Examples are therefore directly relevant to operational conditions.
These following Tests illustrate the criticality of the pH at which water treatment according to the invention is carried out.
The water treated had the following properties.
pH 7.8
Turbidity 9 FTU
Colour 17 Hazen
Residual Al 0.05 mg A1/l-1 Residual Fe 0.21 mg Foe/1 1 The flocculating agents used were polyaluminium chloride (PAC) and ferric chloride, for comparative purposes and two basic Iron chlorides according to the invention, one of 40% Basicity and the other of 80%
Basicity. The dosage rate was 5 mgl 1 as M203 except for the PAC which was used at 3mug/1~1 as Awl203. Samples of the water having pH values of 5.0, 5.5, 6.0, 6.5 and 7.0 by addition of sulphuric acid (10% w/w) were dosed over a period of 3 minutes with stirring at 60 rpm and were subsequently stirred at 15 rpm for 20 minutes.The samples were then allowed to stand for 30 minutes before examination and analysis.
The Turbidity, Colour and Residual Fe of the treated samples are indicated in Figure I, parts A, B and C respectively the pH related performance of the basic iron chloride samples being highlighted by the superimpos tion of a curve.
It is remarked, generally, that since the interact ions involved are on the molecular level the effectiveness of dosage rates requires comparison on a molar basis between the iron-based and the aluminium-based flocculating agents which implies a weighting factor of 0.64 to be applied to the basic iron salts. Thus the dosage rates of these salts and of the PAC are equivalent.
The following Tests illustrate the effect of various flocculating agents at a standard pH of 6.0 but at varying dosage rates.
The water to be treated had the following properties.
pH 7.3
Colour 38 Hazen
Residual Fe 0.92 mg.l 1 ResidualAl 0.05 mg.l#1 The treating technique was the same as that described in the previous Tests.
The results are summarised in the following Table.
Test No. Flocculant Dose Floc Colour Residual
mg M2O3.l-l Size Hazen Fe mg.l 1 1 Aluminium 8 D 6 0. 38 2 Sulphate 9 D-E 9 0.40 3 10 E 8 0. 41 4 PAC 8 E 8 0.22 5 Basic Fe 8 D 6 0.20 5 Chloride 40% 9 D 5 0.18 7 10 D-E 4 0.14 8 Basic Fe 8 D-E 7 0.17 9 Chloride 9 E 7 0.16 10 80% 10 E-F 6 0.12
In the instances where the basic iron chlorides had been used the residual aluminium content of the water remained unchanged as a result of treatment. In the instances where aluminium containing flocculating agents had been used the residual aluminium content of the treated water was found to have increased as follows :
Dose mg.l#1 Residual Al mg.l- Aluminium Sulphate 8 + 0.15
9 + 0.20
10 + 0.05
PAC 8 + 0.10
Claims (13)
- CLAIMS 1. A process for the purification of water by contactIng the water with an effective quantity of a flocculating agent comprising a basic ferric salt wherein the flocculation is improved by adjusting the pH of the water or sludge by the addition to the water, in addition to the basic ferric salt, of an acidic or basic substance.
- 2. A process as claimed in claim 1 wherein the flocculating agent is a 20% to 90% basic ferric chloride or sulphate.
- 3. A process as claimed in claim 1 or 2 wherein the flocculating agent is present in the water at a concentration of from 1 mg/l to 50 mg/l.
- 4. A process as claimed in any preceding claim wherein the flocculation is improved by adjusting the pH of the water to a point in the range of 5 to less than7.5.
- 5. A process as claimed in claim 4 wherein the pH is adjusted to a point in the range of 5.25 to 6.75.
- 6. A process as claimed in claim 4 wherein alkaline water is to be purified and there is added thereto in addition to the basic ferric salt a quantity of an acidic substance sufficient to adjust the pH to within the said range.
- 7. A process as claimed in claim 6 wherein the acidic substance is selected from hydrochloric and sulphuric acids.
- 8. A process as claimed In claim 6 wherein the water has a pE of from 7.5 to
- 9.C 9. A process as claimed In claim 4 wherein acidic water is to be purified and there is added to the water, in addition to the basic ferric salt, a quantity of a basic substance sufficient to adjust the pH to within the said range.
- 10. A process as claimed in claim 9 wherein thebasic substance is selected from lime or caustic soda or chemIcal equivalents thereof.
- 11. Water or other aqueous liquid whenever purified by a process as claimed in any receding claim.
- 12. A process as claimed in claim 1 and substantially as described herein.
- 13. A process as claimed in claim 12 with particular reference to any one of Tests 5 to 7 described herein or to Figure 1.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB878715155A GB8715155D0 (en) | 1987-06-25 | 1987-06-25 | Purification of waters |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8813929D0 GB8813929D0 (en) | 1988-07-20 |
| GB2208164A true GB2208164A (en) | 1989-03-08 |
| GB2208164B GB2208164B (en) | 1991-04-24 |
Family
ID=10619719
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB878715155A Pending GB8715155D0 (en) | 1987-06-25 | 1987-06-25 | Purification of waters |
| GB8813929A Expired GB2208164B (en) | 1987-06-25 | 1988-06-13 | Purification of water using a flocculating agent |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB878715155A Pending GB8715155D0 (en) | 1987-06-25 | 1987-06-25 | Purification of waters |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB8715155D0 (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1275757A (en) * | 1968-05-27 | 1972-05-24 | Efa Forschung | Process and apparatus for separating oil from emulsions of oil in water |
| GB1468091A (en) * | 1973-02-09 | 1977-03-23 | Apothekernes Lab | Method for recovering and stabilizing fat and fatty substances as well as proteins and proteinous substances from aqueous effluents |
| GB1526129A (en) * | 1975-10-09 | 1978-09-27 | Tokai Electro Chemical Co | Solid-liquid separation method for organic waste sludge |
| US4125466A (en) * | 1976-05-18 | 1978-11-14 | Toyo Soda Manufacturing Co., Ltd. | Treatment of sludge comprising biological aggregate |
| JPS61161197A (en) * | 1985-01-11 | 1986-07-21 | Kankyo Eng Kk | Treatment of organic waste water |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3544476A (en) * | 1967-05-09 | 1970-12-01 | Taki Fertilizer Mfg Co Ltd | Coagulant and method for treating aqueous medium comprising a basic metal salt and a multivalent anion |
| EP0022475A1 (en) * | 1979-07-06 | 1981-01-21 | Allied Corporation | Aqueous basic polyaluminum-iron halide solutions and method of preparing |
| EP0168752B2 (en) * | 1984-07-13 | 1994-12-14 | Hitachi, Ltd. | Method of treating liquid wastes containing heavy metal chelate compounds |
-
1987
- 1987-06-25 GB GB878715155A patent/GB8715155D0/en active Pending
-
1988
- 1988-06-13 GB GB8813929A patent/GB2208164B/en not_active Expired
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1275757A (en) * | 1968-05-27 | 1972-05-24 | Efa Forschung | Process and apparatus for separating oil from emulsions of oil in water |
| GB1468091A (en) * | 1973-02-09 | 1977-03-23 | Apothekernes Lab | Method for recovering and stabilizing fat and fatty substances as well as proteins and proteinous substances from aqueous effluents |
| GB1526129A (en) * | 1975-10-09 | 1978-09-27 | Tokai Electro Chemical Co | Solid-liquid separation method for organic waste sludge |
| US4125466A (en) * | 1976-05-18 | 1978-11-14 | Toyo Soda Manufacturing Co., Ltd. | Treatment of sludge comprising biological aggregate |
| JPS61161197A (en) * | 1985-01-11 | 1986-07-21 | Kankyo Eng Kk | Treatment of organic waste water |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2208164B (en) | 1991-04-24 |
| GB8715155D0 (en) | 1987-08-05 |
| GB8813929D0 (en) | 1988-07-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5510040A (en) | Removal of selenium from water by complexation with polymeric dithiocarbamates | |
| US4981675A (en) | Polymeric basic aluminum silicate-sulphate | |
| EP0551061B1 (en) | Process for the preparation of a coagulating chemical | |
| US3388060A (en) | Process and composition for purification of water supplies and aqueous wastes | |
| US6123854A (en) | Flocculant compositions and water treatment method using the same | |
| US4201667A (en) | Process for removing arsenic from aqueous mediums | |
| Mohammed et al. | Phosphorus removal from water and waste water by chemical precipitation using alum and calcium chloride | |
| US3928195A (en) | Liquid purifying process | |
| RU2034795C1 (en) | Method of extraction of phosphate and organophosphate from sewage | |
| Yigit et al. | Phosphate recovery potential from wastewater by chemical precipitation at batch conditions | |
| US4172784A (en) | Process for the separation of cadmium (Cd++)-ions from sewage, waste water and aqueous solutions | |
| KR20130055321A (en) | Process for preparing a high alkalinity flocculant for watertreatment mixed active silicate | |
| EP0062016B1 (en) | An aluminium chloride composition and a method for its manufacture | |
| US4814106A (en) | Manufacture of a basic metal hydroxysulfate complex in solid form | |
| JPS6366278B2 (en) | ||
| JPS62262789A (en) | Method for removing phosphorus | |
| US4707273A (en) | Manganese removal from aqueous industrial waste effluents | |
| GB2208164A (en) | Purification of waters | |
| RU2131849C1 (en) | Method of preparing coagulation-flocculation reagent and water treatment process | |
| KR102578887B1 (en) | Method of producing PloyAluminumFerricSulfate aqueous solution | |
| CN1095442C (en) | Active polysilicate flocculating agent and preparation method thereof | |
| JPH091154A (en) | Treatment method for wastewater containing phosphoric acid | |
| US2281759A (en) | Sewage treatment | |
| US4166033A (en) | Process for the separation of polyvinyl alcohol from aqueous solutions | |
| CN1099720A (en) | Preparing method for zinc polysilicate flocculate agent and use |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19930613 |