NZ621402B2 - Micronized caco3 slurry injection system for the remineralization of desalinated and fresh water - Google Patents
Micronized caco3 slurry injection system for the remineralization of desalinated and fresh water Download PDFInfo
- Publication number
- NZ621402B2 NZ621402B2 NZ621402A NZ62140212A NZ621402B2 NZ 621402 B2 NZ621402 B2 NZ 621402B2 NZ 621402 A NZ621402 A NZ 621402A NZ 62140212 A NZ62140212 A NZ 62140212A NZ 621402 B2 NZ621402 B2 NZ 621402B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- water
- slurry
- calcium carbonate
- previous
- concentration
- Prior art date
Links
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 232
- 239000002002 slurry Substances 0.000 title claims abstract description 111
- 230000000395 remineralization Effects 0.000 title claims description 43
- 238000002347 injection Methods 0.000 title claims description 14
- 239000007924 injection Substances 0.000 title claims description 14
- VTYYLEPIZMXCLO-UHFFFAOYSA-L calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims abstract description 252
- 229910000019 calcium carbonate Inorganic materials 0.000 claims abstract description 113
- 229960003563 Calcium Carbonate Drugs 0.000 claims abstract description 112
- 238000000034 method Methods 0.000 claims abstract description 111
- 239000002245 particle Substances 0.000 claims abstract description 48
- CURLTUGMZLYLDI-UHFFFAOYSA-N carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 23
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 23
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 23
- 239000011575 calcium Substances 0.000 claims description 35
- 238000005429 turbidity Methods 0.000 claims description 29
- 229910052791 calcium Inorganic materials 0.000 claims description 28
- 229960005069 Calcium Drugs 0.000 claims description 27
- OYPRJOBELJOOCE-UHFFFAOYSA-N calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 27
- 235000019738 Limestone Nutrition 0.000 claims description 22
- 239000006028 limestone Substances 0.000 claims description 22
- 239000007787 solid Substances 0.000 claims description 16
- UIIMBOGNXHQVGW-UHFFFAOYSA-M NaHCO3 Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 15
- 239000010459 dolomite Substances 0.000 claims description 14
- 229910000514 dolomite Inorganic materials 0.000 claims description 14
- VEXZGXHMUGYJMC-UHFFFAOYSA-N HCl Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 13
- 229910000041 hydrogen chloride Inorganic materials 0.000 claims description 13
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 13
- 235000010755 mineral Nutrition 0.000 claims description 13
- 239000011707 mineral Substances 0.000 claims description 13
- 239000003651 drinking water Substances 0.000 claims description 11
- 235000020188 drinking water Nutrition 0.000 claims description 11
- 238000002360 preparation method Methods 0.000 claims description 11
- 239000002351 wastewater Substances 0.000 claims description 11
- FYYHWMGAXLPEAU-UHFFFAOYSA-N magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 10
- 239000011777 magnesium Substances 0.000 claims description 10
- 229910052749 magnesium Inorganic materials 0.000 claims description 10
- CSNNHWWHGAXBCP-UHFFFAOYSA-L mgso4 Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims description 10
- 239000003673 groundwater Substances 0.000 claims description 9
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate dianion Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 8
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 8
- 239000012267 brine Substances 0.000 claims description 7
- 235000017557 sodium bicarbonate Nutrition 0.000 claims description 7
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims description 7
- 238000009285 membrane fouling Methods 0.000 claims description 6
- ZLNQQNXFFQJAID-UHFFFAOYSA-L Magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 claims description 5
- 239000001095 magnesium carbonate Substances 0.000 claims description 5
- 239000011776 magnesium carbonate Substances 0.000 claims description 5
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims description 5
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims description 5
- 235000019341 magnesium sulphate Nutrition 0.000 claims description 5
- TYJJADVDDVDEDZ-UHFFFAOYSA-M Potassium bicarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 claims description 4
- HHSPVTKDOHQBKF-UHFFFAOYSA-J calcium;magnesium;dicarbonate Chemical compound [Mg+2].[Ca+2].[O-]C([O-])=O.[O-]C([O-])=O HHSPVTKDOHQBKF-UHFFFAOYSA-J 0.000 claims description 4
- 239000008235 industrial water Substances 0.000 claims description 4
- 239000000395 magnesium oxide Substances 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 239000008239 natural water Substances 0.000 claims description 4
- 229910052700 potassium Inorganic materials 0.000 claims description 4
- 239000011736 potassium bicarbonate Substances 0.000 claims description 4
- 235000015497 potassium bicarbonate Nutrition 0.000 claims description 4
- 229910000028 potassium bicarbonate Inorganic materials 0.000 claims description 4
- 229940086066 potassium hydrogencarbonate Drugs 0.000 claims description 4
- 229960003975 Potassium Drugs 0.000 claims description 3
- 239000003621 irrigation water Substances 0.000 claims description 3
- 235000012245 magnesium oxide Nutrition 0.000 claims description 3
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 3
- 239000011591 potassium Substances 0.000 claims description 3
- KEAYESYHFKHZAL-UHFFFAOYSA-N sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 claims description 3
- 229910052708 sodium Inorganic materials 0.000 claims description 3
- 239000011734 sodium Substances 0.000 claims description 3
- VNWKTOKETHGBQD-AKLPVKDBSA-N carbane Chemical compound [15CH4] VNWKTOKETHGBQD-AKLPVKDBSA-N 0.000 claims 1
- 238000003860 storage Methods 0.000 abstract description 7
- 235000010216 calcium carbonate Nutrition 0.000 description 79
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 16
- 235000015450 Tilia cordata Nutrition 0.000 description 16
- 235000011941 Tilia x europaea Nutrition 0.000 description 16
- 239000004571 lime Substances 0.000 description 16
- 239000007788 liquid Substances 0.000 description 13
- 238000001223 reverse osmosis Methods 0.000 description 11
- 238000007792 addition Methods 0.000 description 10
- -1 anion hydroxide Chemical class 0.000 description 10
- 239000004579 marble Substances 0.000 description 10
- 241000196324 Embryophyta Species 0.000 description 9
- 229940088417 PRECIPITATED CALCIUM CARBONATE Drugs 0.000 description 9
- 238000002156 mixing Methods 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 8
- 238000001914 filtration Methods 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 239000012528 membrane Substances 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 239000000243 solution Substances 0.000 description 7
- AXCZMVOFGPJBDE-UHFFFAOYSA-L Calcium hydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 6
- 231100001010 corrosive Toxicity 0.000 description 6
- 231100000078 corrosive Toxicity 0.000 description 6
- HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 238000004090 dissolution Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 239000012466 permeate Substances 0.000 description 5
- 238000000108 ultra-filtration Methods 0.000 description 5
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 235000014380 magnesium carbonate Nutrition 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 4
- 239000002352 surface water Substances 0.000 description 4
- 229940014598 TAC Drugs 0.000 description 3
- 230000003139 buffering Effects 0.000 description 3
- 239000000920 calcium hydroxide Substances 0.000 description 3
- 235000011116 calcium hydroxide Nutrition 0.000 description 3
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 238000010612 desalination reaction Methods 0.000 description 3
- 238000005189 flocculation Methods 0.000 description 3
- 230000016615 flocculation Effects 0.000 description 3
- 239000011435 rock Substances 0.000 description 3
- 238000004062 sedimentation Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 239000011343 solid material Substances 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- 230000002194 synthesizing Effects 0.000 description 3
- 235000013619 trace mineral Nutrition 0.000 description 3
- 239000011573 trace mineral Substances 0.000 description 3
- 239000003643 water by type Substances 0.000 description 3
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L Calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- 239000004111 Potassium silicate Substances 0.000 description 2
- NNHHDJVEYQHLHG-UHFFFAOYSA-N Potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 2
- 239000004115 Sodium Silicate Substances 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N Sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- UXVMQQNJUSDDNG-UHFFFAOYSA-L cacl2 Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 description 2
- 238000005345 coagulation Methods 0.000 description 2
- 230000015271 coagulation Effects 0.000 description 2
- 230000000875 corresponding Effects 0.000 description 2
- 238000010908 decantation Methods 0.000 description 2
- 238000004821 distillation Methods 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 230000036541 health Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000002906 microbiologic Effects 0.000 description 2
- 238000001728 nano-filtration Methods 0.000 description 2
- 230000003204 osmotic Effects 0.000 description 2
- 239000011236 particulate material Substances 0.000 description 2
- 229910052913 potassium silicate Inorganic materials 0.000 description 2
- 235000019353 potassium silicate Nutrition 0.000 description 2
- 230000005180 public health Effects 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- BPQQTUXANYXVAA-UHFFFAOYSA-N silicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 2
- 239000001187 sodium carbonate Substances 0.000 description 2
- 229910000029 sodium carbonate Inorganic materials 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 229910052911 sodium silicate Inorganic materials 0.000 description 2
- 239000008234 soft water Substances 0.000 description 2
- 241000894007 species Species 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- WNROFYMDJYEPJX-UHFFFAOYSA-K Aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- PZZYQPZGQPZBDN-UHFFFAOYSA-N Aluminium silicate Chemical compound O=[Al]O[Si](=O)O[Al]=O PZZYQPZGQPZBDN-UHFFFAOYSA-N 0.000 description 1
- JHLNERQLKQQLRZ-UHFFFAOYSA-N Calcium silicate Chemical compound [Ca+2].[Ca+2].[O-][Si]([O-])([O-])[O-] JHLNERQLKQQLRZ-UHFFFAOYSA-N 0.000 description 1
- 235000014653 Carica parviflora Nutrition 0.000 description 1
- 244000132059 Carica parviflora Species 0.000 description 1
- 229910001141 Ductile iron Inorganic materials 0.000 description 1
- PAZHGORSDKKUPI-UHFFFAOYSA-N Lithium metasilicate Chemical compound [Li+].[Li+].[O-][Si]([O-])=O PAZHGORSDKKUPI-UHFFFAOYSA-N 0.000 description 1
- 235000010624 Medicago sativa Nutrition 0.000 description 1
- 240000004658 Medicago sativa Species 0.000 description 1
- KJFMBFZCATUALV-UHFFFAOYSA-N Phenolphthalein Chemical compound C1=CC(O)=CC=C1C1(C=2C=CC(O)=CC=2)C2=CC=CC=C2C(=O)O1 KJFMBFZCATUALV-UHFFFAOYSA-N 0.000 description 1
- 102100000672 SMPX Human genes 0.000 description 1
- 108060007673 SMPX Proteins 0.000 description 1
- ZSDSQXJSNMTJDA-UHFFFAOYSA-N Trifluralin Chemical compound CCCN(CCC)C1=C([N+]([O-])=O)C=C(C(F)(F)F)C=C1[N+]([O-])=O ZSDSQXJSNMTJDA-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 150000007933 aliphatic carboxylic acids Chemical class 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical class [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000007900 aqueous suspension Substances 0.000 description 1
- 230000001580 bacterial Effects 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- 230000003115 biocidal Effects 0.000 description 1
- 239000003139 biocide Substances 0.000 description 1
- 230000033558 biomineral tissue development Effects 0.000 description 1
- 239000007853 buffer solution Substances 0.000 description 1
- 239000001110 calcium chloride Substances 0.000 description 1
- 229910001628 calcium chloride Inorganic materials 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 229910001748 carbonate mineral Inorganic materials 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 239000011083 cement mortar Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 230000001419 dependent Effects 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- XGZRAKBCYZIBKP-UHFFFAOYSA-L disodium;dihydroxide Chemical compound [OH-].[OH-].[Na+].[Na+] XGZRAKBCYZIBKP-UHFFFAOYSA-L 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 230000035622 drinking Effects 0.000 description 1
- 235000021271 drinking Nutrition 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- VTLYFUHAOXGGBS-UHFFFAOYSA-N fe3+ Chemical class [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 1
- 230000004634 feeding behavior Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000005755 formation reaction Methods 0.000 description 1
- 238000005194 fractionation Methods 0.000 description 1
- 239000012510 hollow fiber Substances 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 239000008258 liquid foam Substances 0.000 description 1
- 229910052912 lithium silicate Inorganic materials 0.000 description 1
- 159000000003 magnesium salts Chemical class 0.000 description 1
- 238000005374 membrane filtration Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000010445 mica Substances 0.000 description 1
- 229910052618 mica group Inorganic materials 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006011 modification reaction Methods 0.000 description 1
- 238000006385 ozonation reaction Methods 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 229910052904 quartz Inorganic materials 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000001046 rapid expansion of supercritical solution Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 125000005373 siloxane group Chemical group [SiH2](O*)* 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
- 238000004450 types of analysis Methods 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B5/00—Water
-
- 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
- C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
-
- 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
- C02F1/008—Control or steering systems not provided for elsewhere in subclass C02F
-
- 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
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
-
- 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
- C02F1/68—Treatment of water, waste water, or sewage by addition of specified substances, e.g. trace elements, for ameliorating potable water
-
- 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
- C02F2001/007—Processes including a sedimentation step
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/001—Runoff or storm water
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/02—Non-contaminated water, e.g. for industrial water supply
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/08—Seawater, e.g. for desalination
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/003—Downstream control, i.e. outlet monitoring, e.g. to check the treating agents, such as halogens or ozone, leaving the process
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/05—Conductivity or salinity
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/05—Conductivity or salinity
- C02F2209/055—Hardness
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/06—Controlling or monitoring parameters in water treatment pH
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/07—Alkalinity
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/10—Solids, e.g. total solids [TS], total suspended solids [TSS] or volatile solids [VS]
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/11—Turbidity
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/24—CO2
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2301/00—General aspects of water treatment
- C02F2301/04—Flow arrangements
- C02F2301/043—Treatment of partial or bypass streams
-
- 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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
Abstract
Disclosed is a process for treating water comprising: (a) providing feed water from as reservoir (1) having a concentration of carbon dioxide of at 5 least 20 mg/l; (b) providing an aqueous slurry comprising micronized calcium carbonate from a storage tank (6), wherein the calcium carbonate has a particle size from 0.5 to 50 ?m; and (c) combining the feed water of step a) in a pipeline (2) and the aqueous slurry of step b) from an inlet (4) in order to obtain remineralised water. rticle size from 0.5 to 50 ?m; and (c) combining the feed water of step a) in a pipeline (2) and the aqueous slurry of step b) from an inlet (4) in order to obtain remineralised water.
Description
Micronized CaCO slurry injection system for the remineralization of
desalinated and fresh water
The invention relates generally to the field of water treatment, and more specifically
to a process for remineralization of water and the use of calcium carbonate in such a
process.
Drinking water has become scarce. Even in countries that are rich in water, not all
sources and reservoirs are suitable for the production of drinking water, and many
sources of today are threatened by a dramatic deterioration of the water quality.
Initially feed water used for drinking purposes was mainly surface water and
groundwater. However the treatment of seawater, brine, brackish waters, waste
waters and contaminated effluent waters is gaining more and more importance for
environmental and economic reasons.
In order to recover water from seawater or brackish water, for potable usages, several
processes are known, which are of considerable importance for dry areas, coastal
regions and sea islands, and such processes comprise distillation, electrolytic as well
as osmotic or reverse osmotic processes. The water obtained by such processes is
very soft and has a low pH value because of the lack of pH-buffering salts, and thus,
tends to be highly reactive and unless treated, it can create severe corrosion
difficulties during its transport in conventional pipelines. Furthermore, untreated
desalinated water cannot be used directly as a source of drinking water. To prevent
the dissolution of undesirable substances in pipeline systems, to avoid the corrosion
of water works such as pipes and valves and to make the water palatable, it is
necessary to remineralize the water.
Conventional processes that are mainly used for the remineralization of water are
lime dissolution by carbon dioxide and limestone bed filtration. Other, less common
remineralization processes, comprise, e.g., the addition of hydrated lime and sodium
carbonate, the addition of calcium sulfate and sodium bicarbonate, or the addition of
calcium chloride and sodium bicarbonate.
The lime process involves treatment of lime solution with CO acidified water,
wherein the following reaction is involved:
2+ −
Ca(OH) +2CO →Ca +2 HCO
2 2 3
As can be gathered from the above reaction scheme, two equivalents of CO are
necessary to convert one equivalent of Ca(OH) into Ca and bicarbonate for
remineralization. This method is dependent on the addition of two equivalents of
CO , in order to convert the basic anion hydroxide into the buffering bicarbonate
species. For the remineralization of water, a saturated calcium hydroxide solution,
commonly named lime water, of 0.1-0.2 wt.-% based on the total weight, is prepared
from a lime milk (usually at most 5 wt.-%). Therefore a saturator to produce the lime
water must thereof be used and large volumes of lime water are necessary to achieve
the target level of remineralization. A further drawback of this method is that
hydrated lime is corrosive and requires appropriate handling and specific equipment.
Furthermore, a poorly controlled addition of hydrated lime to the soft water can lead
to unwanted pH shifts due to the absence of buffering properties of lime.
The limestone bed filtration process comprises the step of passing the soft water
through a bed of granular limestone dissolving the calcium carbonate in the water
flow. Contacting limestone with CO acidified water mineralizes the water according
to:
2+ −
CaCO +CO +H O→Ca +2 HCO
3 2 2 3
Unlike the lime process, only one equivalent of CO is stoichiometrically necessary
to convert one equivalent of CaCO into Ca and bicarbonate for remineralization.
Moreover, limestone is not corrosive and due to the buffering properties of CaCO
major pH shifts are prevented.
One additional advantage of using calcium carbonate instead of lime is its very low
carbon dioxide footprint. In order to produce one ton of calcium carbonate 75 kg of
CO is emitted, whereas 750 kg of CO is emitted for the production of one ton of
lime. Therefore the use of calcium carbonate instead of lime presents some
environmental benefits.
However, the dissolution rate of granular calcium carbonate is slow and large filters
are needed for the limestone filtration process. That causes a sizeable footprint of
these filters, and large plant surfaces are required for such limestone bed filtration
systems.
Methods for remineralization of water using lime milk or a slurry of lime are
described in US 7,374, 694 and EP 0 520826. US 5,914,046 describes a method for
reducing the acidity in effluent discharges using a pulsed limestone bed.
The applicant also knows unpublished European Patent Application 10 172 771.7
describing a method for the remineralization of desalinated and fresh water by
injecting micronized calcium carbonate slurry and gaseous carbon dioxide in feed
water.
However, all of the above cited prior art documents describe processes for the
remineralization of feed water containing no or a low concentration of carbon
dioxide before the remineralization process.
Yet, there also exists feed water having a high or sufficient concentration of carbon
dioxide before the remineralization process, based on the level or remineralization
wanted. By a high or sufficient concentration of carbon dioxide it is meant an amount
of at least 20 mg CO per liter of feed water.
One type of feed water having such a high concentration of carbon dioxide is ground
water originating from water that has been percolating through calcareous rocks or
due to anaerobic conditions.
Another type of feed water having a concentration of carbon dioxide of at least 20
mg/l, can for example be found during the treatment of waste water in a sewage
plant. The reason therefor is that one treatment step of the waste water consists in the
desalination of the waste water by the use of reverse osmosis. However, in order to
prevent or reduce scale formation on the membranes of the reverse osmosis
apparatus, acid, in particular sulfuric acid is added to the reverse osmosis feed water
in order to lower the pH. The addition of acid in the reverse osmosis feed leads to a
conversion of the carbonate species in the feed water to free carbon dioxide which is
not removed by the membranes of the reverse osmosis apparatus and thus is present
in the feed water leaving the osmosis apparatus. This excess carbon dioxide present
in the feed water, however, has to be removed before the addition of lime. At present,
the removal of the excess carbon dioxide in the feed water is carried out by using
cost-, time- and energy consuming decarbonators.
Thus, considering the drawbacks of the known processes for remineralization of
water, it is an object of the present invention to provide an alternative or improved
process for remineralization of water having an initial concentration of carbon
dioxide of at least 20 mg/l, and where the remineralized water has a defined level of
remineralization, for example a calcium concentration of 30 to 40 mg/l as CaCO
and/or
to provide a process for the remineralization of water that does not require a
corrosive compound, and thus, avoids the danger of incrustation, eliminates the need
for corrosion resistant equipment, and provides a safe environment for people
working in the plant and/or that at least provides the public with a useful choice,
and/or
to provide a process that is environmental friendly and that reduces the operational
costs due to the omission of a time-, energy- and cost consuming process step,
and/or
to provide a process for remineralization of water, wherein the amount of minerals
can be adjusted to the required values and/or to provide a process for
remineralization using limestone that allows the use of smaller remineralization
units, or to provide a remineralization process that allows the use of smaller volumes
of the remineralization compound, for instance, in comparison with the lime process,
and/or
to provide a process that can be operated on smaller plant surfaces than the limestone
bed filtration process, and/or to at least provide the public with a useful choice.
Accordingly, in one aspect the present invention relates to a process for
remineralization of water comprising the steps of:
a) providing feed water having a concentration of carbon dioxide of 30
to 60 mg/l,
b) providing an aqueous slurry comprising micronized calcium
carbonate, wherein the calcium carbonate has a particle size from 0.5
to 50 µm, and
c) combining the feed water of step a) and the aqueous slurry of step b)
in order to obtain remineralized water, wherein the concentration of
calcium carbonate in the slurry is from 2 to 20 wt.-% based on the
total weight of the slurry.
Also described herein is a process for remineralization of water comprising the steps
of (a) providing feed water having a concentration of carbon dioxide of at least 20
mg/l, preferably in a range of 25 to 100 mg/l, and more preferably in a range of 30 to
60 mg/l, (b) providing an aqueous slurry comprising micronized calcium carbonate,
and (c) combining the feed water of step a) and the aqueous slurry of step b) in order
to obtain remineralized water.
According to another aspect, the present invention relates to the use of a micronized
calcium carbonate for remineralization of water, wherein the calcium carbonate has a
particle size from 0.5 to 50 µm.
In the description in this specification reference may be made to subject matter which
is not within the scope of the appended claims. That subject matter should be readily
identifiable by a person skilled in the art and may assist in putting into practice the
invention as defined in the appended claims.
Certain statements that appear below are broader than what appears in the statements
of the invention above. These statements are provided in the interests of providing
the reader with a better understanding of the invention and its practice. The reader is
directed to the accompanying claim set which defines the scope of the invention.
Advantageous embodiments of the present invention are defined in the
corresponding sub-claims.
According to one embodiment the concentration of calcium carbonate in the slurry is
from 0.05 to 40 wt.-%, from 1 to 25 wt.-%, from 2 to 20 wt.-%, preferably from 3 to
wt.-%, and most preferably from 5 to 10 wt.-% based on the total weight of the
slurry, or the concentration of calcium carbonate in the slurry is from 10 to 40 wt.-%,
from 15 to 30 wt.-%, or from 20 to 25 wt.-% based on the total weight of the slurry.
According to another embodiment the calcium carbonate has a particle size from 0.1
to 100 µm, from 0.5 to 50 µm, from 1 to 15 µm, preferably from 2 to 10 µm, most
preferably 3 to 5 µm, or the calcium carbonate has a particle size from 1 to 50 µm,
from 2 to 20 µm, preferably from 5 to 15 µm, most preferably 8 to 12 µm. According
to still another embodiment the calcium carbonate has a HCl insoluble content from
0.02 to 2.5 wt.-%, 0.05 to 1.5 wt.-%, or 0.1 to 0.6 wt.-% based on the total weight of
the micronized calcium carbonate. According to still another embodiment the
calcium carbonate is a ground calcium carbonate, modified calcium carbonate, or
precipitated calcium carbonate, or mixtures thereof.
According to one embodiment the slurry comprises further minerals containing
magnesium, potassium or sodium, preferably magnesium carbonate, calcium
magnesium carbonate, e.g. dolomitic limestone, calcareous dolomite, dolomite or
half-burnt dolomite; magnesium oxide such as burnt dolomite, magnesium sulfate,
potassium hydrogen carbonate, or sodium hydrogen carbonate. According to another
embodiment the slurry is freshly prepared by mixing water and the calcium
carbonate. According to still another embodiment the time period between the
preparation of the slurry and the injection of the slurry is less than 48 hours, less than
24 hours, less than 12 hours, less than 5 hours, less than 2 hours or less than 1 hour.
According to still another embodiment the injected slurry meets microbiological
quality requirements specified by the national guidelines for drinking water.
According to one embodiment the obtained remineralized water has a calcium
concentration as calcium carbonate from 15 to 200 mg/l, preferably from 50 to
150 mg/l, and most preferred from 100 to 125 mg/l, or from 15 to 100 mg/l,
preferably from 20 to 80 mg/l, and most preferably from 40 to 60 mg/l.
According to another embodiment the obtained remineralized water has a
magnesium concentration from 5 to 25 mg/l, preferably from 5 to 15 mg/l, and most
preferred from 8 to 12 mg/l. According to still another embodiment the remineralized
water has a turbidity value of lower than 5.0 NTU, lower than 1.0 NTU, lower than
0.5 NTU, or lower than 0.3 NTU.
According to another preferred embodiment the remineralized water has a Langelier
Saturation Index from -2 to 1, preferably from -1.9 to 0.9, and most preferably from -
0.9 to 0. According to still another embodiment the remineralized water has a Slit
Density Index SDI below 5, preferably below 4, and most preferred below 3.
According to still another embodiment the remineralized water has a Membrane
Fouling Index MFI below 4, preferably below 2.5, most preferred below 2.
0.45
According to one embodiment the feed water is desalinated seawater, brackish water
or brine, treated wastewater or natural water such as ground water, surface water or
rainfall, and preferably desalinated seawater, brackish water or brine, treated
wastewater or ground water.
According to one embodiment the remineralized water is blended with feed water.
According to another embodiment the process further comprises a particle removal
step.
According to one embodiment the process further comprises the steps of (d)
measuring a parameter value of the remineralized water, wherein the parameter is
selected from the group comprising alkalinity, total hardness, conductivity, calcium
concentration, pH, CO concentration, total dissolved solids, and turbidity of the
remineralized water, (e) comparing the measured parameter value with a
predetermined parameter value, and (f) providing the amount of injected slurry on
the basis of the difference between the measured and the predetermined parameter
value. According to another embodiment the predetermined parameter value is a pH
value, wherein the pH value is from 5.5 to 9, preferably from 7 to 8.5.
According to one embodiment the micronized calcium carbonate is used for
remineralization of water, wherein the remineralized water is selected from drinking
water, recreation water such as water for swimming pools, industrial water for
process applications, irrigation water, or water for aquifer or well recharge.
The term “comprising” as used in this specification and claims means “consisting at
least in part of”. When interpreting statements in this specification and claims which
include the term “comprising”, other features besides the features prefaced by this
term in each statement can also be present. Related terms such as “comprise” and
“comprised” are to be interpreted in similar manner.
The term "alkalinity (TAC)" as used in the present invention is a measure of the
ability of a solution to neutralize acids to the equivalence point of carbonate or
bicarbonate. The alkalinity is equal to the stoichiometric sum of the bases in solution
and is specified in mg/l as CaCO . The alkalinity may be measured with a titrator.
For the purpose of the present invention the term "calcium concentration" refers to
the total calcium content in the solution and is specified in mg/l as Ca or as CaCO .
The concentration may be measured with a titrator.
"Conductivity" in the meaning of the present invention is used as an indicator of how
salt-free, ion-free, or impurity-free the measured water is; the purer the water, the
lower the conductivity. The conductivity can be measured with a conductivity meter
and is specified in μS/cm.
"Ground calcium carbonate (GCC)" in the meaning of the present invention is a
calcium carbonate obtained from natural sources including marble, chalk, limestone
or dolomite. Calcite is a carbonate mineral and the most stable polymorph of calcium
carbonate. The other polymorphs of calcium carbonate are the minerals aragonite and
vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less
stable. Ground calcium carbonate is processed through a treatment such as grinding,
screening and/or fractionizing by wet and/or dry, for example, by a cyclone. It is
known to the skilled person that ground calcium carbonate can inherently contain a
defined concentration of magnesium, such as it is the case for dolomitic calcite.
The term "Langelier Saturation Index (LSI)" as used in the present invention
describes the tendency of an aqueous liquid to be scale-forming or corrosive, with a
positive LSI indicating scale-forming tendencies and a negative LSI indicating a
corrosive character. A balanced Langelier Saturation Index, i.e. LSI=0, therefore
means that the aqueous liquid is in chemical balance. The LSI is calculated as
follows:
LSI = pH – pH ,
wherein pH is the actual pH value of the aqueous liquid and pH is the pH value of
the aqueous liquid at CaCO saturation. The pH can be estimated as follows:
pH = (9.3 + A + B) – (C + D),
wherein A is the numerical value indicator of total dissolved solids (TDS) present in
the aqueous liquid, B is the numerical value indicator of temperature of the aqueous
liquid in K, C is the numerical value indicator of the calcium concentration of the
aqueous liquid in mg/l of CaCO , and D is the numerical value indicator of alkalinity
of the aqueous liquid in mg/l of CaCO . The parameters A to D are determined using
the following equations:
A = (log (TDS) – 1)/10,
B = -13.12 × log (T + 273) + 34.55,
C = log [Ca ] – 0.4,
D = log (TAC),
wherein TDS are the total dissolved solids in mg/l, T is the temperature in °C, [Ca ]
is the calcium concentration of the aqueous liquid in mg/l of CaCO , and TAC is the
alkalinity of the aqueous liquid in mg/l of CaCO .
The term "Silt Density Index (SDI)" as used in the present invention refers to the
quantity of particulate matter in water and correlates with the fouling tendency of
reverse osmosis or nanofiltration systems. The SDI can be calculated, e.g., from the
rate of plugging of a 0.45 μm membrane filter when water is passed through at a
constant applied water pressure of 208.6 kPa. The SDI value is calculated from the
rate of plugging of a 0.45 μm membrane filter when water is passed through at a
constant applied water pressure of 208.6 kPa during 15 min. Typically, spiral wound
reverse osmosis systems will need an SDI less than 5, and hollow fiber reverse
osmosis systems will need an SDI less than 3.
The term "Modified Fouling Index (MFI)" as used in the present invention refers to
the concentration of suspended matter and is a more accurate index than the SDI for
predicting the tendency of a water to foul reverse osmosis or nanofiltration
membranes. The method that can be used for determining the MFI may be the same
as for the SDI except that the volume is recorded every 30 seconds over a 15 minute
filtration period. The MFI can be obtained graphically as the slope of the straight part
of the curve when t/V is plotted against V (t is the time in seconds to collect a
volume of V in liters). A MFI value of <1 corresponds to a SDI value of about <3
and can be considered as sufficiently low to control colloidal and particulate fouling.
In case an ultrafiltration (UF) membrane is used for MFI measurements, the index is
called MFI-UF in contrast to the MFI where a 0.45 μm membrane filter is used.
0.45
For the purpose of the present invention, the term "micronized" refers to a particle
size in the micrometer range, e.g., a particle size from 0.1 to 100 µm. The micronized
particles may be obtained by techniques based on friction, e.g., milling or grinding
either under wet or dry conditions. However, it is also possible to produce the
micronized particles by any other suitable method, e.g., by precipitation, rapid
expansion of supercritical solutions, spray drying, classification or fractionation of
natural occurring sands or muds, filtration of water, sol-gel processes, spray reaction
synthesis, flame synthesis, or liquid foam synthesis.
Throughout the present document, the "particle size" of a calcium carbonate product
is described by its distribution of particle sizes. The value d represents the diameter
relative to which x % by weight of the particles have diameters less than d . This
means that the d value is the particle size at which 20 wt.-% of all particles are
smaller, and the d value is the particle size at which 75 wt.-% of all particles are
smaller. The d value is thus the weight median particle size, i.e. 50 wt.-% of all
grains are bigger or smaller than this particle size. For the purpose of the present
invention the particle size is specified as weight median particle size d unless
indicated otherwise. For determining the weight median particle size d value for
particles having a d greater than 0.5 µm, a Sedigraph 5100 device from the
company Micromeritics, USA can be used.
"Precipitated calcium carbonate (PCC)" in the meaning of the present invention is a
synthesized material, generally obtained by precipitation following the reaction of
carbon dioxide and lime in an aqueous environment or by precipitation of a calcium
and carbonate source in water or by precipitation of calcium and carbonate ions, for
example CaCl and Na CO , out of solution. Precipitated calcium carbonate exists in
2 2 3
three primary crystalline forms: calcite, aragonite and vaterite, and there are many
different polymorphs (crystal habits) for each of these crystalline forms. Calcite has a
trigonal structure with typical crystal habits such as scalenohedral (S-PCC),
rhombohedral (R-PCC), hexagonal prismatic, pinacoidal, colloidal (C-PCC), cubic,
and prismatic (P-PCC). Aragonite is an orthorhombic structure with typical crystal
habits of twinned hexagonal prismatic crystals, as well as diverse assortment of thin
elongated prismatic, curved bladed, steep pyramidal, chisel shaped crystals,
branching tree, and coral or worm-like form.
"Modified calcium carbonate" in the meaning of the present invention is a surface-
reacted natural calcium carbonate that is obtained by a process where natural calcium
carbonate is reacted with one more acids having a pK at 25°C of 2.5 or less and with
gaseous CO formed in situ and/or coming from an external supply, and optionally in
the presence of at least one aluminum silicate and/or at least one synthetic silica
and/or at least one calcium silicate and/or at least one silicate of a monovalent salt
such as sodium silicate and/or potassium silicate and/or lithium silicate, and/or at
least one aluminum hydroxide and/or at least one sodium and/or potassium silicate.
Further details about the preparation of the surface-reacted natural calcium carbonate
are disclosed in WO 00/39222 and US 2004/0020410 A1, the contents of these
references herewith being included in the present patent application.
The term "remineralization" as used in the present invention refers to the restoration
of minerals in water not containing minerals at all or in a sufficient amount to obtain
a water that is palatable. A remineralization can be achieved by adding at least
calcium carbonate to the water to be treated. Optionally, e.g., for health-related
benefits or to ensure the appropriate intake of some essential minerals and trace
elements, further substances may be mixed to the calcium carbonate and then added
to the water during the remineralization process. According to the national guidelines
on human health and drinking water quality, the remineralized product may comprise
additional minerals containing magnesium, potassium or sodium, e.g., magnesium
carbonate, magnesium sulfate, potassium hydrogen carbonate, sodium hydrogen
carbonate or other minerals containing essential trace elements.
For the purpose of the present invention, a "slurry" comprises insoluble solids and
water and optionally further additives and usually contains large amounts of solids
and, thus, is more viscous and generally of higher density than the liquid from which
it is formed.
The term "total dissolved solids (TDS)" as used in the present invention is a measure
of the combined content of all inorganic and organic substances contained in a liquid
in molecular, ionized or micro-granular (colloidal sol) suspended form. Generally the
operational definition is that the solids must be small enough to survive filtration
through a sieve the size of two micrometer. The total dissolved solids can be
estimated with a conductivity meter and are specified in mg/l.
"Turbidity" in the meaning of the present invention describes the cloudiness or
haziness of a fluid caused by individual particles (suspended solids) that are
generally invisible to the naked eye. The measurement of turbidity is a key test of
water quality and can be carried out with a nephelometer. The units of turbidity from
a calibrated nephelometer as used in the present invention are specified as
Nephelometric Turbidity Units (NTU).
The inventive process for remineralization of water comprises the steps of (a)
providing feed water having a concentration of carbon dioxide of at least 20 mg/l,
preferably in the range of 25 to 100 mg/l, and more preferably in a range of 30 to 60
mg/l, (b) providing an aqueous slurry comprising micronized calcium carbonate, and
(c) combining the feed water of step (a) and the aqueous slurry of step (b) in order to
obtain remineralized water.
The feed water to be is used in the inventive process can be derived from various
sources. The feed water preferably treated by the process of the present invention is
desalinated seawater, brackish water or brine, treated wastewater or natural water
such as ground water, surface water or rainfall, and more preferably desalinated
seawater, brackish water or brine, treated wastewater or ground water.
According to one embodiment, the feed water can be pretreated. A pretreatment may
be necessary, e.g., in case the feed water is derived from surface water, groundwater
or rainwater. For example, to achieve the drinking water guidelines the water need to
be treated through the use of chemical or physical techniques in order to remove
pollutants such as organics and undesirable minerals. For example, ozonation can be
used as a first pretreatment step, followed then by coagulation, flocculation, or
decantation as a second treatment step. For example, iron(III) salts such as FeClSO
or FeCl , or aluminum salts such as AlCl , Al (SO ) or polyaluminium may used as
3 3 2 4 3
flocculation agents. The flocculated materials can be removed from the feed water,
e.g, by means of sand filters or multi-layered filters. Further water purification
processes that may be used to pretreat the feed water are described, e.g., in EP
1 975 310, EP 1 982 759, EP 1 974 807, or EP 1 974 806.
According to another exemplary embodiment, sea water or brackish water is firstly
pumped out of the sea by open ocean intakes or subsurface intakes such as wells, and
then it undergoes physical pretreatments such as screens, sedimendation or sand
removal process. Depending on the required water quality, additional treatment steps
such as coagulation and flocculation may be necessary in order to reduce potential
fouling on the membranes. The pretreated seawater or brackish water may then be
distilled, e.g., using multiple stage flash, multiple effect distillation, or membrane
filtration such as ultrafiltration or reverse osmosis, to remove the remaining
particulates and dissolved substances.
The remineralization of the feed water is induced by combining the feed water
having a concentration of carbon dioxide of at least 20 mg/l, preferably in a range of
to 100 mg/l, and more preferably in a range of 30 to 60 mg/l with the aqueous
slurry comprising the micronized calcium carbonate. The combination of the feed
water and the aqueous slurry can be achieved by common methods known to the
skilled person, and for example, by injecting the aqueous slurry comprising the
micronized calcium carbonate into the feed water
The aqueous slurry that combined with the feed water comprises micronized calcium
carbonate. According to one embodiment the concentration of calcium carbonate in
the slurry is from 0.05 to 40 wt.-%, from 1 to 25 wt.-%, from 2 to 20 wt.-%, from 3
to 15 wt.-%, or from 5 to 10 wt.-% based on the total weight of the slurry. According
to another embodiment the concentration of calcium carbonate in the slurry is from
to 40 wt.-%, from 15 to 30 wt.-%, or from 20 to 25 wt.-% based on the total
weight of the slurry.
The micronized calcium carbonate possesses a particle size in the micrometer range.
According to one embodiment, the micronized calcium has a particle size from 0.1 to
100 µm, from 0.5 to 50 µm, from 1 to 15 µm, 2 to 10 µm or from 3 to 5 µm or the
calcium carbonate has a particle size from 1 to 50 µm, from 2 to 20 µm, preferably
from 5 to 15 µm, most preferably 8 to 12 µm.
Examples for suitable calcium carbonates are ground calcium carbonate, modified
calcium carbonate or precipitated calcium carbonate, or a mixture thereof. A natural
ground calcium carbonate (GCC) may feature, e.g., one or more of marble,
limestone, chalk, and/or dolomite. A precipitated calcium carbonate (PCC) may
feature, e.g., one or more of aragonitic, vateritic and/or calcitic mineralogical crystal
forms. Aragonite is commonly in the acicular form, whereas vaterite belongs to the
hexagonal crystal system. Calcite can form scalenohedral, prismatic, spheral, and
rhombohedral forms. A modified calcium carbonate may feature a natural ground or
precipitated calcium carbonate with a surface and/or internal structure modification,
e.g., the calcium carbonate may be treated or coated with a hydrophobising surface
treatment agent such as, e.g. an aliphatic carboxylic acid or a siloxane. Calcium
carbonate may be treated or coated to become cationic or anionic with, for example,
a polyacrylate or polydadmac.
According to one embodiment, the micronized calcium carbonate is a ground
calcium carbonate (GCC). According to a preferred embodiment, the micronized
calcium carbonate is a ground calcium carbonate having a particle size from 3 to 5
µm, or 8 to 12 µm.
According to another embodiment, the micronized calcium carbonate comprises a
HCl insoluble content from 0.02 to 2.5 wt.-%, 0.05 to 1.5 wt.-%, or 0.1 to 0.6 wt.-%
based on the total weight of the micronized calcium carbonate. Preferably, the HCl
insoluble content of the micronized calcium carbonate does not exceed 0.6 wt.-%
based on the total weight of the micronized calcium carbonate. The HCl insoluble
content may be, e.g., minerals such as quartz, silicate or mica.
In addition to the micronized calcium carbonate, the slurry can comprise further
micronized minerals. According to one embodiment, the slurry can comprise
micronized magnesium carbonate, calcium magnesium carbonate, e.g. dolomitic
limestone, calcareous dolomite, dolomite or half-burnt dolomite; magnesium oxide
such as burnt dolomite, magnesium sulfate, potassium hydrogen carbonate, sodium
hydrogen carbonate or other minerals containing essential trace elements.
According to one embodiment, the slurry is freshly prepared by mixing water and the
micronized calcium carbonate. The on-site preparation of the slurry may be preferred
since premixed slurries may require the addition of further agents such as stabilizers
or biocides, which may be unwanted compounds in the remineralized water.
According to one preferred embodiment, the time period between the preparation of
the slurry and the injection of the slurry is short enough to avoid bacterial growth in
the slurry. According to one exemplary embodiment, the time period between the
preparation of the slurry and the injection of the slurry is less than 48 hours, less than
24 hours, less than 12 hours, less than 5 hours, less than 2 hours or less than 1 hour.
According to another embodiment, the injected slurry meets the microbiological
quality requirements specified by the national guidelines for drinking water.
The slurry can be prepared, for example, using a mixer such as a mechanical stirrer
for dilute slurries, or a specific powder-liquid mixing device for more concentrate
slurries. Depending on the concentration of the prepared slurry the mixing time may
be from 0.5 to 30 min, from 1 to 20 min, from 2 to 10 min, or from 3 to 5 min.
According to one embodiment, the slurry is prepared using a mixing machine,
wherein the mixing machine enables simultaneous mixing and dosing of the slurry.
The water used to prepare the slurry can be, e.g., distilled water, feed water or
industrial water.
According to one embodiment the slurry comprising micronized calcium carbonate is
injected directly into a stream of feed water. For example, the slurry can be injected
into the feed water stream at a controlled rate by means of a pump communicating
with a storage vessel for the slurry. Preferably, the slurry may be injected into the
feed water stream at a rate of 1 to10 liter per cubic meter of feed water depending on
the slurry concentration. According to another embodiment the slurry comprising
micronized calcium carbonate is mixed with the feed water in a reaction chamber,
e.g., using a mixer such as a mechanical stirrer. According to still another
embodiment the slurry is injected in a tank receiving the entire flow of feed water.
According to one embodiment, only a part of the feed water is remineralized by
injecting the slurry, and subsequently, the remineralized water is blended with
untreated feed water. Optionally, only a part of the feed water is remineralized to a
high calcium carbonate concentration in comparison with the final target values, and
subsequently, the remineralized water is blended with untreated feed water.
According to another embodiment the treated water or part of the treated water is
filtered, e.g., by ultra filtration, to further reduce the turbidity level of the
remineralized water.
According to one embodiment, the slurry is injected in such an amount that complete
dissolution of the calcium carbonate is achieved.
The amount of calcium carbonate injected into the feed water is selected in such way
so as to give a water of desired quality. For example the quality of the remineralized
water can be assessed by the Langelier Saturation Index (LSI). According to one
embodiment, the remineralized water has a Langelier Saturation Index from -2 to 1,
preferably from -1.9 to 0.9, and most preferably from -0.9 to 0. According to another
embodiment, the remineralized water has a Slit Density Index SDI below 5,
preferably below 4, and most preferred below 3. According to still another
embodiment the remineralized water has a Membrane Fouling Index MFI below 4,
0.45
preferably below 2.5, most preferred below 2. The assessment can be done, e.g., by
measuring the pH of the treated feed water continuously. Depending on the
remineralization system, the pH of the treated pH can be measured, e.g., in a stream
of treated water, in a reaction chamber, wherein the slurry and the feed water is
mixed, or in a storage tank for the remineralized water. According to one
embodiment, the pH is measured 30 min, 20 min, 10 min, 5 min or 2 min after the
remineralization step. The measurement of the pH value may be done at room
temperature, i.e. at about 20°C.
According to one exemplary embodiment, the amount of the injected slurry is
controlled by detecting the pH value of the treated feed water. Alternatively or
additionally, the amount of injected slurry is controlled by detecting parameters such
as alkalinity, total hardness, conductivity, CO concentration, pH, calcium
concentration, total dissolved solids, or turbidity. According to one embodiment, the
process further comprises the steps of (d) measuring a parameter value of the
remineralized water, wherein the parameter is selected from the group comprising
alkalinity, total hardness, conductivity, calcium concentration, pH, CO
concentration, total dissolved solids, or turbidity of the remineralized water, (e)
comparing the measured parameter value with a predetermined parameter value, and
(f) providing the amount of injected slurry on the basis of the difference between the
measured and the predetermined parameter value.
According to one embodiment, the predetermined parameter value is a pH value,
wherein the pH value is from 5.5 to 9, preferably from 7 to 8.5.
Fig. 1 shows a scheme of an apparatus that can be used for operating the inventive
method. Feed water flows from a reservoir (1) into a pipeline (2). An inlet (4) is
located downstream the pipeline (2) through which the slurry comprising micronized
calcium carbonate is injected into the feed water stream from a storage tank (6) for
the slurry. The slurry is prepared on-site using a suitable mixer (8) by mixing water
that is obtained from the reservoir (1) via a pipe (10) and micronized calcium
carbonate obtained from a storage container (12). The pH of the remineralized water
can be measured downstream of the slurry inlet (10) on a sample point (14).
According to one embodiment the flow rate of the feed water is 20 000 and
500 000 m per day.
The inventive process may be used to produce drinking water, recreation water such
as water for swimming pools, industrial water for process applications, irrigation
water, or water for aquifer or well recharge.
According to one embodiment, the carbon dioxide and calcium carbonate
concentrations in the remineralized water meet the required values for drinking water
quality, which are set by national guidelines. According to one embodiment the
remineralized water obtained by the inventive process has a calcium concentration
from 15 to 200 mg/l as CaCO , preferably from 50 to 150 mg/l as CaCO , and most
preferred from 100 to 125 mg/l as CaCO , or from 15 to 100 mg/l, preferably from
to 80 mg/l, and most preferably from 40 to 60 mg/l. In case the slurry comprises a
further magnesium salt such as magnesium carbonate, or magnesium sulfate, the
remineralized water obtained by the inventive process may have a magnesium
concentration from 5 to 25 mg/l, preferably from 5 to 15 mg/l, and most preferred
from 8 to 12 mg/l.
According to one embodiment the remineralized water has a turbidity of lower than
.0 NTU, lower than 1.0 NTU, lower than 0.5 NTU, or lower than 0.3 NTU.
According to one exemplary embodiment the remineralized water has a LSI from -
0.9 to +0.0, a calcium concentration from 15 to 200 mg/l, a magnesium concentration
from 5 to 25 mg/l, an alkalinity between 20 and 100 mg/l as CaCO3, a pH between 7
and 8.5, and a turbidity of lower than 1.0 NTU.
According to one embodiment a step of particle removal is carried out after
mineralization, e.g., to reduce the turbidity level of the remineralized water. It is also
possible to carry out a particle removal step before the injection of the slurry, e.g., to
reduce the turbidity level of the feed water or part of the feed water. According to
one embodiment a sedimentation step is carried out. For example, the feed water
and/or remineralized water may be piped into a clarifier or storage tank to further
reduce the turbidity level of the water. According to another embodiment the
particles may be removed by decantation. Alternatively, at least a part of the feed
water and/or remineralized water may be filtered, e.g., by ultra filtration, to further
reduce the turbidity level of the water.
The invention will now be described in detail by the following examples.
Examples
Measurement methods:
CO measurement
The concentration of carbon dioxide contained in the feed water samples used was
determined by using a titrimetric method. The principle of this method consists in
the fact that CO reacts with sodium carbonate or sodium hydroxide to form
sodium bicarbonate (NaHCO ). The completion of the reaction is indicated
potentiometrically or by the development of the pink colour characteristic of
phenolphthalein indicator at the equivalence pH of 8.3
The titration of the feed water was conducted at 25°C using a Mettler Toledo M
416.
A three point calibration (according to the segment method) of the instrument was
first made using commercially available buffer solutions (from Mettler Toledo)
having pH values of 4.01, 7.00 and 9.21.
Then the pH of a 100 ml sample of the feed water was measured in function of the
amount of titrant used until the end-point of pH 8 was reached. In the present
measurement the titrant was a 0.01 mol/l sodium hydroxide solution.
From the amount of titrant that was necessary to reach the end-point of pH 8.3, and
using the following equation (I), the CO content can be easily calculated.
A×N×44000
mg CO /L = (I)
where:
A = ml titrant, N = normality of NaOH, and b = ml sample.
Formula (I) is described in Chapter 4500-CO Carbon Dioxide on pages 4-28 to 4-34
of “Standard Methods for the Examination of Water & Wastewater, 21 Edition,
2005, prepared and published jointly by the American Public Health Association,
American Water Works Association, Water Environment Federation, publication
office American Public Health Association 800 I Street, NW, Washington, DC
20001-3710, Centennial Edition”. Therefrom it can be derived that the CO contents
given in the present invention refer to the content of free CO in the water.
BET specific surface area
The BET specific surface area (also designated as SSA) was determined according to
ISO 9277 using a Tristar II 3020 sold by the company MICROMERITICS .
Particle size distribution (mass % particles with a diameter < X µm) and weight
median particle diameter (d ) of particulate material (d (µm))
50 50
Sedigraph 5100
The weight median particle diameter and the particle diameter mass distribution of a
particulate material were determined via the sedimentation method, i.e. an analysis of
sedimentation behavior in a gravimetric field. The measurement is made with a
TM TM
Sedigraph 5100 sold by the company MICROMERITICS .
The method and the instrument are known to the skilled person and are commonly
used to determine particle size of fillers and pigments. Samples were prepared by
adding an amount of the product corresponding to 4 g dry PCC to 60 ml of an
aqueous solution of 0.1 % by weight of Na P O . The samples were dispersed for 3
4 2 7
minutes using a high speed stirrer (Polytron PT 3000/3100 at 15,000 rpm). Then it
was submitted to ultrasound using an ultrasonic bath for 15 minutes and thereafter
added to the mixing chamber of the Sedigraph.
Weight solids (% by weight) of a material in suspension
The weight solids (also called solids content of a material) was determined by
dividing the weight of the solid material by the total weight of the aqueous
suspension.
The weight of the solid material was determined by weighing the solid material
obtained by evaporating the aqueous phase of the suspension and drying the obtained
material to a constant weight.
The micronized products used to prepare the slurries of the present invention
consisted of several micronized carbonate rocks:
a marble calcium carbonate with an HCl insoluble content of 1.5 wt.-% from
Bathurst, Australia, with d = 2.8 µm (sample A),
a marble calcium carbonate with an HCl insoluble content of 0.1 wt.-% from
Salses, France, with two different particle sizes d = 5.5 µm (sample D), and
d = 3.5 µm (sample E),
a limestone calcium carbonate with an HCl insoluble content of 0.7 wt.-%
from Superior, Arizona (sample F: d = 3.5 µm),
a marble calcium carbonate with an HCl insoluble content of 1.0 wt.-% from
Lucerne Valley, California (sample J: d = 2.0 µm)
a limestone calcium carbonate with an HCl insoluble content of 0.1 wt.-%
from Orgon, France (sample K: d = 3.0 µm)
Table 1 summaries the different products used during the remineralization tests
Samples Calcium carbonate rock d (µm) HCl insoluble (%)
A Marble 2.8 1.5
D Marble 5.5 0.2
E Marble 3.5 0.2
F Limestone 3.5 0.7
J Marble 2.0 1.0
K Limestone 3.0 0.1
Table 1
Membrane Fouling Index (MFI) and Langelier Saturation Index (LSI) during
remineralization of the RO water:
Permeate produced by desalination processes is corrosive to concrete and metal
because of its low pH and LSI value. If the permeate is not stabilized it leaches
calcium from unprotected concrete in the storage tanks, wells and corrodes the
cement-mortar lined ductile iron pipe commonly used for water distribution. At the
majority of advanced water and wastewater treatment facilities permeate is stabilized
by the addition of chemicals such as lime.
However, the dosing of chemicals for post-treatment may result in high turbidity
(> 0.2 NTU) and elevated particulate levels (high Modified Fouling Index, e.g. in the
2 - 15 units range) in the final treated water, thereby increasing the potential for
fouling of the injection wells.
For indirect potable use, injection to barrier wells for seawater intrusion control it is
specified that the permeate water turbidity shall be < 0.2 NTU units and the modified
fouling index (MFI) shall be < 2.0 units.
The feed water used for the remineralization tests of the present examples was
obtained from a reverse osmosis desalination process of two different sewage
plants (Plant 1 and Plant 2) and had the following parameters:
Parameter Plant 1 Plant 2
pH 5.58 5.54
Alkalinity (mg/L as
21.0 9.0
CaCO )
Ca Hardness (mg/L) 0.8 0.8
CO (mg/L) 35.0 45.0
Turbidity (NTU) 0.3 0.2
TDS (mg/L) 12.6 6.7
LSI -5.0 -5.3
MFI 0.1 0.3
The RO permeate remineralization tests were performed using 2-liter cubic jars
with the aim of increasing the hardness of the RO water, e.g. 0.8 mg/L as CaCO ,
up to the target of around 50 mg/L as CaCO .
Different types of micronized calcium carbonate (samples A, D, E, F, J and K)
were tested for MFI and LSI analyses. The solid content of the CaCO slurries
was 3.5 wt%, based on the weight of the micronized calcium carbonate. An
appropriate dose of the CaCO slurries was added to achieve the desired water
quality. The stabilized finished water should reach the following quality
requirements:
Parameter Value
pH 6.5 to 8.5
Alkalinity, mg/L as CaCO 40 to 80
Calcium, mg/L 10 to 50
LSI -0.5 to 0.0
Turbidity, NTU < 0.2
MFI < 2.0
After adding the CaCO slurry, the samples were allowed to mix for 4 hours and
samples collected at 10, 20, 30, 60, 120, and 240 minutes. Turbidity, pH, total
alkalinity, and calcium hardness was measured at the individual sampling times.
Equilibrium time was determined as the time when the turbidity stabilized. After the
equilibrium time was reached, LSI was calculated and MFI measured.
Table 2 shows the different results obtained for the remineralization of two
different RO waters after the addition of approximately 50 mg/L as CaCO using
3.5 wt% CaCO slurries, based on the weight of the micronized calcium
carbonate.
Equilibrium Alkalinity Turbidity LSI MFI
water pH
CaCO slurries
time (min) (mg/L CaCO ) (NTU) (units) (units)
supply
Sample J
Plant 1 120 7.6 49 1.3 -1.2 1.6
(marble,
d = 2.0 μm)
Sample F
Plant 1 120 7.5 49 0.7 -0.88 1.9
(limestone,
d = 3.5 μm)
Sample J
Plant 2 120 7.8 41 1.3 -0.88 1.3
(marble,
d = 2.0 μm)
Sample F
Plant 2 120 7.8 43 1.7 -1.02 1.7
(limestone,
d = 3.5 μm)
Sample K
Plant 2 120 7.9 44 0.5 -1.61 0.1
(limestone,
d = 3.0 μm)
Sample E
Plant 2 120 7.9 43 0.9 -1.8 0.62
(marble,
d = 3.5 μm)
Sample D
Plant 2 120 7.9 41 1.2 -1.7 0.5
(marble,
d = 5.5 μm)
Sample A
Plant 2 120 8.0 48 1.4 -1.85 1.9
(marble,
d = 2.8 μm)
Table 2
As it can be taken from Table 2, the use of micronized calcium carbonate products
for the remineralization of RO water met the water quality requirements for pH, total
alkalinity, calcium hardness, and MFI for all performed tests. The micronized
calcium carbonate products presented turbidity level between 0.5 and 1.7 NTU, and
LSI values between -1.85 and -0.88. Based on turbidity measurements with respect to
time, equilibrium time required for dissolution of calcium carbonate products was
approximately 120 minutes.
In this specification where reference has been made to patent specifications, other
external documents, or other sources of information, this is generally for the purpose
of providing a context for discussing the features of the invention. Unless
specifically stated otherwise, reference to such external documents is not to be
construed as an admission that such documents, or such sources of information, in
any jurisdiction, are prior art, or form part of the common general knowledge in the
art.
Claims (68)
1. Process for remineralization of water comprising the steps of: a) providing feed water having a concentration of carbon dioxide of 30 5 to 60 mg/l, b) providing an aqueous slurry comprising micronized calcium carbonate, wherein the calcium carbonate has a particle size from 0.5 to 50 µm, and c) combining the feed water of step a) and the aqueous slurry of step b) 10 in order to obtain remineralized water, wherein the concentration of calcium carbonate in the slurry is from 2 to 20 wt.-% based on the total weight of the slurry.
2. The process of claim 1, wherein the feed water has a concentration of carbon 15 dioxide in a range of 25 to 100 mg/l.
3. The process of claim 1 or 2, wherein the feed water has a concentration of carbon dioxide in a range of 30 to 60 mg/l. 20
4. The process of any one of claims 1 to 3, wherein the concentration of calcium carbonate in the slurry is from 0.05 to 40 wt.-% based on the total weight of the slurry.
5. The process of any one of claims 1 to 4, wherein the concentration of calcium 25 carbonate in the slurry is from 1 to 25 wt.-% based on the total weight of the slurry.
6. The process of any one of claims 1 to 5, wherein the concentration of calcium carbonate in the slurry is from 2 to 20 wt.-% based on the total weight of the 30 slurry.
7. The process of any one of claims 1 to 6, wherein the concentration of calcium carbonate in the slurry is from 3 to 15 wt.-% based on the total weight of the slurry. 5
8. The process of any one of claims 1 to 7, wherein the concentration of calcium carbonate in the slurry is from 5 to 10 wt.-% based on the total weight of the slurry.
9. The process of any one of claims 1 to 4, wherein the concentration of calcium 10 carbonate in the slurry is from 10 to 40 wt.-% based on the total weight of the slurry.
10. The process of any one of claims 1 to 4 and 9, wherein the concentration of calcium carbonate in the slurry is from 15 to 30 wt.-% based on the total 15 weight of the slurry.
11. The process of any one of claims 1 to 4, 9 and 10, wherein the concentration of calcium carbonate in the slurry is from 20 to 25 wt.-% based on the total weight of the slurry.
12. The process of any one of the previous claims, wherein the calcium carbonate has a particle size from 1 to 15 µm.
13. The process of any one of the previous claims, wherein the calcium carbonate 25 has a particle size from 2 to 10 µm.
14. The process of any one of the previous claims, wherein the calcium carbonate has a particle size from 3 to 5 µm. 30
15. The process of any one of claims 1 to 11, wherein the calcium carbonate has a particle size from 1 to 50 µm.
16. The process of any one of claims 1 to 11 and 15, wherein the calcium carbonate has a particle size from 2 to 20 µm. 5
17. The process of any one of claims 1 to 11, 15 and 16, wherein the calcium carbonate has a particle size from 5 to 15 µm.
18. The process of any one claims 1 to 11 and 15 to 17, wherein the calcium carbonate has a particle size from 8 to 12 µm.
19. The process of any one of the previous claims, wherein the calcium carbonate has a HCl insoluble content from 0.02 to 2.5 wt.-% based on the total weight of the micronized calcium carbonate. 15
20. The process of any one of the previous claims, wherein the calcium carbonate has a HCl insoluble content from 0.05 to 1.5 wt.-% based on the total weight of the micronized calcium carbonate.
21. The process of any one of the previous claims, wherein the calcium carbonate 20 has a HCl insoluble content from 0.1 to 0.6 wt.-% based on the total weight of the micronized calcium carbonate.
22. The process of any one of the previous claims, wherein the calcium carbonate is a ground calcium carbonate, modified calcium carbonate, or precipitated 25 calcium carbonate, or mixtures thereof.
23. The process of any one of the previous claims, wherein the slurry comprises further minerals containing magnesium, potassium or sodium. 30
24. The process of any one of the previous claims, wherein the slurry comprises magnesium carbonate, calcium magnesium carbonate, magnesium oxide, magnesium sulfate, potassium hydrogen carbonate, or sodium hydrogen carbonate.
25. The process of claim 24, wherein the calcium magnesium carbonate is 5 dolomitic limestone, calcareous dolomite, dolomite or half-burnt dolomite.
26. The process of claim 24, wherein the magnesium oxide is burnt dolomite.
27. The process of any one of claims 23 to 26, wherein the time period between 10 the preparation of the slurry and the injection of the slurry is less than 48 hours.
28. The process of any one of claims 23 to 27, wherein the time period between the preparation of the slurry and the injection of the slurry is less than 15 24 hours.
29. The process of any one of claims 23 to 28, wherein the time period between the preparation of the slurry and the injection of the slurry is less than 12 hours.
30. The process of any one of claims 23 to 29, wherein the time period between the preparation of the slurry and the injection of the slurry is less than 5 hours. 25
31. The process of any one of claims 23 to 30, wherein the time period between the preparation of the slurry and the injection of the slurry is less than 2 hours.
32. The process of any one of claims 23 to 31, wherein the time period between 30 the preparation of the slurry and the injection of the slurry is less than 1 hour.
33. The process of any one of the previous claims, wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 15 to 200 mg/l. 5
34. The process of any one of the previous claims, wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 50 to 150 mg/l.
35. The process of any one of the previous claims, wherein the obtained 10 remineralized water has a calcium concentration as calcium carbonate from 100 to 125 mg/l.
36. The process of any one of claims 1 to 32, wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 15 to 100 mg/l.
37. The process of any one of claims 1 to 32 and 36, wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 20 to 80 mg/l. 20
38. The process of any one of claims 1 to 32, 36 and 37, wherein the obtained remineralized water has a calcium concentration as calcium carbonate from 40 to 60 mg/l.
39. The process of any one of claims 23 to 38, wherein the obtained 25 remineralized water has a magnesium concentration from 5 to 25 mg/l.
40. The process of any one of claims 23 to 39, wherein the obtained remineralized water has a magnesium concentration from 5 to 15 mg/l. 30
41. The process of any one of claims 23 to 40, wherein the obtained remineralized water has a magnesium concentration from 8 to 12 mg/l.
42. The process of any one of the previous claims, wherein the remineralized water has a turbidity value of lower than 5.0 NTU. 5
43. The process of any one of the previous claims, wherein the remineralized water has a turbidity value of lower than 1.0 NTU.
44. The process of any one of the previous claims, wherein the remineralized water has a turbidity value of lower than 0.5 NTU.
45. The process of any one of the previous claims, wherein the remineralized water has a turbidity value of lower than 0.3 NTU.
46. The process of any one of the previous claims, wherein the remineralized 15 water has a Langelier Saturation Index from -2 to 1.
47. The process of any one of the previous claims, wherein the remineralized water has a Langelier Saturation Index from -1.9 to 0.9. 20
48. The process of any one of the previous claims, wherein the remineralized water has a Langelier Saturation Index from -0.9 to 0.
49. The process of any one of the previous claims, wherein the remineralized water has a Slit Density Index SDI below 5.
50. The process of any one of the previous claims, wherein the remineralized water has a Slit Density Index SDI below 4.
51. The process of any one of the previous claims, wherein the remineralized 30 water has a Slit Density Index SDI below 3.
52. The process of any one of the previous claims, wherein the remineralized water has a Membrane Fouling Index MFI below 4. 0.45
53. The process of any one of the previous claims, wherein the remineralized 5 water has a Membrane Fouling Index MFI below 2.5. 0.45
54. The process of any one of the previous claims, wherein the remineralized water has a Membrane Fouling Index MFI below 2. 0.45 10
55. The process of any one of the previous claims, wherein the feed water is desalinated seawater, brackish water or brine, treated wastewater or natural water.
56. The process of claim 55, wherein the natural water is ground water, surface 15 water or rainfall.
57. The process of claim 55, wherein the feed water is desalinated seawater, brackish water or brine, treated wastewater or ground water. 20
58. The process according to any one of the previous claims, wherein the remineralized water is blended with feed water.
59. The process according to any one of the previous claims, wherein the process further comprises a particle removal step.
60. The process of any one of the previous claims, wherein the process further comprises the steps of: d) measuring a parameter value of the remineralized water, wherein the parameter is selected from the group comprising alkalinity, 30 conductivity, calcium concentration, pH, total dissolved solids, and turbidity of the remineralized water, e) comparing the measured parameter value with a predetermined parameter value, and f) providing the amount of injected slurry on the basis of the difference between the measured and the predetermined parameter value.
61. The process of claim 60, wherein the predetermined parameter value is a pH value, wherein the pH value is from 5.5 to 9.
62. The process of claim 61, wherein the pH value is from 7 to 8.5.
63. Use of a micronized calcium carbonate for remineralization of water, wherein the calcium carbonate has a particle size from 0.5 to 50 µm.
64. The use of claim 63, wherein the remineralized water is selected from 15 drinking water, recreation water, industrial water for process applications, irrigation water, or water for aquifer or well recharge.
65. The use of claim 64, wherein recreation water is water for swimming pools. 20
66. The process of any one of claims 1 to 62 substantially as herein described with reference to any example thereof and with or without reference to the accompanying figure.
67. Remineralized water when obtained by the process of any one of claims 1 to 25 62 and 66.
68. Use of any one of claims 63 to 65 substantially as herein described with reference to any example thereof and with or without reference to the accompanying figure.
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP11175012.1A EP2548848B1 (en) | 2011-07-22 | 2011-07-22 | Micronized CaCO3 slurry injection system for the remineralization of desalinated and fresh water |
EP11175012.1 | 2011-07-22 | ||
US201161513035P | 2011-07-29 | 2011-07-29 | |
US61/513,035 | 2011-07-29 | ||
PCT/EP2012/063973 WO2013014026A1 (en) | 2011-07-22 | 2012-07-17 | Micronized caco3 slurry injection system for the remineralization of desalinated and fresh water |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ621402A NZ621402A (en) | 2015-05-29 |
NZ621402B2 true NZ621402B2 (en) | 2015-09-01 |
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