CA2815914C - Reactor for recovering phosphate salts from a liquid - Google Patents
Reactor for recovering phosphate salts from a liquid Download PDFInfo
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- CA2815914C CA2815914C CA2815914A CA2815914A CA2815914C CA 2815914 C CA2815914 C CA 2815914C CA 2815914 A CA2815914 A CA 2815914A CA 2815914 A CA2815914 A CA 2815914A CA 2815914 C CA2815914 C CA 2815914C
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- phosphate
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- 239000007788 liquid Substances 0.000 title claims abstract description 26
- 125000002467 phosphate group Chemical class [H]OP(=O)(O[H])O[*] 0.000 title 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 claims abstract description 22
- 239000011777 magnesium Substances 0.000 claims abstract description 18
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 17
- 239000000463 material Substances 0.000 claims abstract description 6
- 239000013078 crystal Substances 0.000 claims description 10
- 238000011084 recovery Methods 0.000 claims description 6
- MXZRMHIULZDAKC-UHFFFAOYSA-L ammonium magnesium phosphate Chemical compound [NH4+].[Mg+2].[O-]P([O-])([O-])=O MXZRMHIULZDAKC-UHFFFAOYSA-L 0.000 claims description 3
- 229910052567 struvite Inorganic materials 0.000 claims description 3
- 239000004020 conductor Substances 0.000 claims description 2
- YQRTZUSEPDULET-UHFFFAOYSA-K magnesium;potassium;phosphate Chemical compound [Mg+2].[K+].[O-]P([O-])([O-])=O YQRTZUSEPDULET-UHFFFAOYSA-K 0.000 claims description 2
- 238000002425 crystallisation Methods 0.000 claims 1
- 230000008025 crystallization Effects 0.000 claims 1
- 229910019142 PO4 Inorganic materials 0.000 abstract description 19
- 239000010452 phosphate Substances 0.000 abstract description 19
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 abstract description 19
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 16
- 238000001556 precipitation Methods 0.000 description 13
- 239000002351 wastewater Substances 0.000 description 11
- 238000000034 method Methods 0.000 description 10
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 9
- 229910001425 magnesium ion Inorganic materials 0.000 description 9
- 229910052757 nitrogen Inorganic materials 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 239000007787 solid Substances 0.000 description 7
- 239000002671 adjuvant Substances 0.000 description 6
- 150000002500 ions Chemical class 0.000 description 6
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 5
- 238000000855 fermentation Methods 0.000 description 5
- 230000004151 fermentation Effects 0.000 description 5
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000007792 addition Methods 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 3
- 239000000347 magnesium hydroxide Substances 0.000 description 3
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 210000003608 fece Anatomy 0.000 description 2
- -1 for example Substances 0.000 description 2
- 239000010871 livestock manure Substances 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 159000000003 magnesium salts Chemical class 0.000 description 2
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000011368 organic material Substances 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 229910052700 potassium Inorganic materials 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 229910000861 Mg alloy Inorganic materials 0.000 description 1
- 238000005273 aeration Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 150000001722 carbon compounds Chemical class 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000006735 deficit Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000010815 organic waste Substances 0.000 description 1
- 230000008635 plant growth Effects 0.000 description 1
- 239000003123 plant toxin Substances 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Classifications
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- 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
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/463—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis by electrocoagulation
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
-
- 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
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/02—Biological treatment
- C02F11/04—Anaerobic treatment; Production of methane by such processes
-
- 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
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/46104—Devices therefor; Their operating or servicing
- C02F1/46109—Electrodes
- C02F2001/46133—Electrodes characterised by the material
-
- 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
- C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
- C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
- C02F1/46104—Devices therefor; Their operating or servicing
- C02F1/46109—Electrodes
- C02F2001/46152—Electrodes characterised by the shape or form
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/105—Phosphorus compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2201/00—Apparatus for treatment of water, waste water or sewage
- C02F2201/002—Construction details of the apparatus
- C02F2201/003—Coaxial constructions, e.g. a cartridge located coaxially within another
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2201/00—Apparatus for treatment of water, waste water or sewage
- C02F2201/46—Apparatus for electrochemical processes
- C02F2201/461—Electrolysis apparatus
- C02F2201/46105—Details relating to the electrolytic devices
- C02F2201/4616—Power supply
- C02F2201/4617—DC only
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Removal Of Specific Substances (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
Abstract
The invention relates to a reactor (10) for completely separating phosphate from a liquid and for recovering phosphate salts, comprising a housing (12) and two electrodes having differing polarities, wherein a sacrificial anode (16) made of a magnesium-containing material and an inert cathode (18) are arranged concentrically inside the housing (12).
Description
Description [0001] Reactor for recovering phosphate salts from a liquid
[0002] The invention concerns a reactor for complete separation of phosphate from a liquid and recovery of phosphate salts, comprising a housing and two electrodes of different polarity.
[0003] Phosphate salts such as magnesium ammonium phosphate (in the following abbreviated as MAP) or potassium magnesium phosphate (in the following abbreviated as PMP) are high-value plant adjuvants for which there is high demand. The elements nitrogen, potassium, magnesium, and phosphate of which these plant adjuvants are comprised are typically contained in all solid or liquid organic waste materials. While potassium, magnesium and other ions are present in the form of water-soluble cations, nitrogen and phosphate are predominantly bound to or in organic material or cell mass. Accordingly, a major proportion of nitrogen and phosphate are not available for the production of plant adjuvants. For this reason it is necessary to convert nitrogen and phosphate into their inorganic form that is suitable for precipitation.
[0004] The spontaneous precipitation of MAP or PMP is limited by the usually very low magnesium concentration in wastewater. Known is the addition of magnesium hydroxide, magnesium oxide or soluble magnesium salts for MAP precipitation. The disadvantage in this context is the bad solubility of the oxides as well as of the salt-like hydroxides. Upon addition of magnesium hydroxide or magnesium oxide to the wastewater, these compounds dissolve only very slowly and with a minimal proportion. This has the result that it is necessary to continuously perform stirring or mixing which, however, causes extra expenditure in regard to technology and energy and thus also with respect to costs. Moreover, both compounds, because of their bad solubility, must be added in over-stoichiometric amounts because otherwise an incomplete precipitation of the desired plant adjuvants occurs and significant quantities of phosphate remain in the wastewater. When magnesium salts are beforehand transferred into a solution, the efficiency of the method decreases because of the dilution with water.
[0005] The optimal pH value for precipitation of MAP is at 9. Wastewater has usually pH values between 5 and 7. Therefore, for increasing the pH
value, a base is added. By using a soluble base, for example, sodium hydroxide. When using a base that is sparingly soluble, for example, magnesium hydroxide, the latter will hardly dissolve in water and the aforementioned disadvantages will occur.
value, a base is added. By using a soluble base, for example, sodium hydroxide. When using a base that is sparingly soluble, for example, magnesium hydroxide, the latter will hardly dissolve in water and the aforementioned disadvantages will occur.
[0006] A further possibility for adjusting a pH value that is favorable for precipitation is disclosed in DE 101 12 934 B4. The aeration of primary sludge mentioned therein with subsequent CO2 stripping is however very energy-intensive and causes therefore high additional costs.
[0007] WO 00200101019735 A1 discloses a reactor for removal of dissolved nitrogen and phosphate from the aqueous portion of liquid manure by means of electrochemical precipitation.
[0008] The reactor described therein requires relatively high electrical voltages and is therefore energy-intensive and cost-intensive. A disadvantage is also that nitrogen and phosphate that are present organically bound in the aqueous portion of the liquid manure cannot be removed by the disclosed method. As a result of this, this wastewater must therefore be subjected to a subsequent purification in a water treatment plant. The construction of the reactor is disadvantageous in that, due to the arrangement of the electrodes, large areas are generated in which the liquid to be purified has no direct contact with the electrodes. Moreover, as a result of the geometry of the sacrificial anode more magnesium than required is released. Both effects reduce the efficiency of the reactor significantly. Moreover, in this method, due to the use of aluminum-containing electrodes, the plant poison aluminum ends up in the precipitation product. When this product is applied to the soil, the aluminum can be released and the plant growth can be affected negatively.
,
,
[0009] An electrochemical precipitation reactor for MAP is disclosed in WO
2007/009749 A1. The reactor is however not suitable for the precipitation of other phosphate salts. Also, the construction of the reactor does not allow for automatic separation between purified wastewater and precipitated MAP so that it is necessary to arranged downstream of the reactor a further apparatus for solid/liquid separation. Also, a significantly higher apparatus expenditure is required because, as a result of the construction, the housing of the reactor cannot be operated as a cathode.
In addition, the magnesium is dissolved non-uniformly because, due to the spatial arrangement of the electrodes in the reactor, only one side of the anode is participating in the reaction.
2007/009749 A1. The reactor is however not suitable for the precipitation of other phosphate salts. Also, the construction of the reactor does not allow for automatic separation between purified wastewater and precipitated MAP so that it is necessary to arranged downstream of the reactor a further apparatus for solid/liquid separation. Also, a significantly higher apparatus expenditure is required because, as a result of the construction, the housing of the reactor cannot be operated as a cathode.
In addition, the magnesium is dissolved non-uniformly because, due to the spatial arrangement of the electrodes in the reactor, only one side of the anode is participating in the reaction.
[0010] The invention has the object to provide a reactor by means of which phosphate-containing wastewater can be treated and supplied to a further use. Moreover, the invention has the object to provide a reactor for recovery of phosphate salts as plant adjuvants which overcomes the aforementioned disadvantages of the prior art.
[0011] The object is solved according to the invention by a reactor with a housing.
At the center of the housing a sacrificial anode of magnesium or a magnesium-containing material is arranged. An inert cathode is arranged concentrically about the sacrificial anode. In this way, the arrangement of the electrodes in accordance with the invention provides for a best possible control of the release of magnesium ions. Since the spacing between magnesium anode and cathode is kept as minimal as possible, the ions that are required for the precipitation of the phosphate salts are immediately in contact with each other and a constantly high concentration of magnesium ions in the reaction space is ensured. At the same time, because of the geometry of the sacrificial anode, its surface is very small so that only little magnesium is spontaneously released. In this way, advantageously an unnecessary excess of magnesium ions is prevented.
At the center of the housing a sacrificial anode of magnesium or a magnesium-containing material is arranged. An inert cathode is arranged concentrically about the sacrificial anode. In this way, the arrangement of the electrodes in accordance with the invention provides for a best possible control of the release of magnesium ions. Since the spacing between magnesium anode and cathode is kept as minimal as possible, the ions that are required for the precipitation of the phosphate salts are immediately in contact with each other and a constantly high concentration of magnesium ions in the reaction space is ensured. At the same time, because of the geometry of the sacrificial anode, its surface is very small so that only little magnesium is spontaneously released. In this way, advantageously an unnecessary excess of magnesium ions is prevented.
[0012] By means of the reactor according to the invention, it is possible by application of a minimal electrical direct current, smaller than 1 V with current strengths below 1 A, to supply magnesium ions to the phosphate-containing and ammonium-containing liquid and to split the water that is contained in the liquid to OH- and H+ ions so that the pH
value is increased and the reactions required for precipitation can take place. Due to the minimal energy demand, the costs for operating the device drop in comparison to methods known from the prior art. It is even possible to operate the reactor by galvanic operation. Electrical current is produced thereby.
value is increased and the reactions required for precipitation can take place. Due to the minimal energy demand, the costs for operating the device drop in comparison to methods known from the prior art. It is even possible to operate the reactor by galvanic operation. Electrical current is produced thereby.
[0013] Moreover, it is proposed that an anaerobic fermentation process is arranged upstream of the reactor according to the invention. In this fermentation process nitrogen and phosphorus that are bound organically are decomposed to inorganic water-soluble ions. From these ions, ammonium (NH4) and phosphate (P043), the phosphate salts, in particular MAP and PMP, can be formed. In this way, nitrogen and phosphate that are bound predominantly to or in organic material or cell mass are converted advantageously into a water-soluble form and are thus available for the production of plant adjuvants. Moreover, in this process biogas is produced which has a significant market value as an energy source.
[0014] An advantageous embodiment of the invention provides that the housing is manufactured of an electrically conductive material, for example, metal and therefore serves as an inert cathode. With the geometry of the reactor according to the invention and the concentric arrangement of the sacrificial anode the reaction space is limited to the space between the two electrodes. In this way, dead space is avoided and thus material costs are lowered.
[0015] A further advantage of the invention provides that the sacrificial anode is comprised substantially of magnesium. Of course, this includes also electrode materials that are comprised of a magnesium alloy or magnesium with minimal additions of other components.
[0016] In order to be able to advantageously perform the process of phosphate salt recovery continuously, the reactor according to the present invention has an inlet for the phosphate-containing liquid, an outlet for the purified liquid, as well as a removal device for the precipitated phosphate salts.
The crystals can be removed via the removal device by means of a shut-off valve, for example, a seat valve or disk valve or ball valve, from the reactor without the inlet or outlet being changed and thereby the purification performance of the reactor being negatively affected.
The crystals can be removed via the removal device by means of a shut-off valve, for example, a seat valve or disk valve or ball valve, from the reactor without the inlet or outlet being changed and thereby the purification performance of the reactor being negatively affected.
[0017] An advantageous embodiment of the reactor according to the invention provides for the operation of the reactor as an upflow reactor. In this context, the inlet is located laterally at the bottom end of the reactor. The wastewater flows upward and escapes laterally at the top. This arrangement has the advantage that an automatic separation of liquid that flows upwardly and precipitated salts that sink to the bottom is taking place.
[0018] In principle, the reactor can be operated also as a downflow reactor wherein the liquid and solid move in the same direction. In this way, the sedimentation rate of the precipitated phosphate salts is accelerated. This means that the reactor can be made smaller for the same throughput.
[0019] In supplementing this, it is proposed that the crystals are separated in a filter from the liquid. In this way, in the reactor that is flowed through from top to bottom the precipitated phosphate salts can be removed together with the liquid from the reactor. Accordingly, additional fixtures or devices for separate solids removal are saved. Also, in case of common removal of phosphate salts and purified wastewater, a turbulent flow is generated in the conduit and prevents clogging of the conduit by the crystals.
[0020] It is particularly beneficial when the housing of the reactor is closed. The electrolytic reactions that occur in the reactor produce large quantities of foam which in case of a closed housing cannot overflow. Accordingly, in an advantageous way, a product loss is avoided. In principle, the housing of the reactor can also be open partially or entirely.
[0021] The reactor according to the invention operates even better when it has a slanted bottom. In this way, it is possible that the precipitated crystals glide along the slanted surface downwardly and collect at the removal device. In this way, the crystals can be removed from the reactor without its continuous operation having to be interrupted. The formation of the slanted surface is realized by a preferably conical bottom. Conceivable is also the shape of a pyramid.
[0022] An advantageous embodiment of the reactor according to the invention provides that to the sacrificial anode a positive pole and to the cathode a negative pole of a direct current source are connected. The supply of electrical current prevents deposits on the electrode which are not stable in the electrical field. When the reactor, on the other hand, is operated without a direct current source, by the process of magnesium release electrons are released. This means that the reactor requires no electrical current but even produces electrical current.
[0023] Further advantages and advantageous embodiments of the invention can be taken from the following Figures, their description, and the claims. In this context, all features disclosed in the Figures, their description, and the claims can be important for the invention individually as well as in any combination with each other.
[0024] It is shown in:
[0025] Figure 1 a schematic illustration of the reactor according to the invention.
[0026] Figure 2 a schematic illustration of a first embodiment of the reactor according to the invention.
[0027] Figure 3 a schematic illustration of a second embodiment of the reactor according to the invention.
[0028] Figure 4 a schematic illustration of a third embodiment of the reactor according to the invention.
[0029] Figure 5 a schematic illustration of a third embodiment of the reactor according to the invention for recovery of phosphate salts.
[0030] Figure 6 a schematic illustration of the use of the reactor according to the invention with upstream fermentation process.
[0031] Figure 1 shows a schematic illustration of a reactor 10 according to the invention. The reactor 10 has a housing 12. The housing 12 serves for receiving a phosphate-containing liquid 14. At the center of the housing 12 an electrode 16 is arranged.
[0032] The electrode 16 is a so-called sacrificial anode which is connected to the positive pole of a direct current source, not illustrated in the drawing, while the housing 12 forms the cathode 18 which is connected to a negative pole of the direct current source.
[0033] The sacrificial anode 16 is comprised of a magnesium-containing material so that magnesium ions are transferred into the solution 14 as soon as electrical voltage is applied to the electrodes 16 and 18.
[0034] Reaction equation for formation of MAP:
[0035] Mg2+ + NH4 + + P043- + 6 H20 -> MgNH4PO4 6 H20
[0036] Reaction equation for formation of PMP:
[0037] Mg2+ + K + P043- + 6 H20 -> MgKPO, 6 H20
[0038] Reaction equation for release of magnesium:
[0039] Mg(s) -> Mg2+ + 2e-
[0040] Reaction equation for formation of hydroxide ions:
[0041] 2 H20 + 2e- -> 2 OH- + H2
[0042] The formed phosphate salts are sparingly soluble in aqueous solution and precipitate as crystals which deposit at a bottom of the reactor 10.
[0043] One configuration of the reactor 10 according to the invention provides for galvanic operation. For this purpose, the two electrodes 16, 18 are not connected to the external direct current source. The magnesium ions are transferred into solution by galvanic operation.
[0044] Figure 2 shows a first embodiment variant of the reactor 10 according to the invention. Illustrated is the housing 12 of the reactor and centrally arranged therein is the electrode 16 that is embodied as a sacrificial anode. Concentric between housing 12 and electrode 16 there is the cathode 18. In this special arrangement the spacing between sacrificial , anode 16 and inert cathode 18 is minimal so that the ions that are participating in the precipitation are immediately in contact with each other.
[0045] In Figure 3 the reactor 10 is illustrated. Laterally at a preferably conical bottom 22 there is an inlet 24. An outlet 26 is located at the top laterally at the housing 12 of the reactor 10. An optional return line 28 connects the outlet 26 with the inlet 24. At the bottom end of the preferably conical bottom 22 there is the removal device 30.
[0046] The phosphate-containing liquid 14 flows through the inlet 24 from the bottom to the top through the reactor 10 and exits from it through the outlet 26. The precipitated phosphate salts glide along the slanted plane of the conical bottom 22 in downward direction and are removed via the removal device 30. In this way, the reactor 10 can be operated continuously and the precipitated and deposited crystals can be removed at any time without changing a throughput of the reactor. By means of the optional return line 28, already purified liquid 14 is returned to the reactor 10 as circulating water.
[0047] Figure 4 shows a third embodiment of the reactor 10 according to the invention. Here, the reactor 10 is flowed through in downward direction.
The inlet 24 is located laterally at the top on the housing 12. The outlet 26 is located laterally at the conical bottom 22. The optional return line 28 connects the outlet 26 with the inlet 24. At the conical bottom 22 the removal device 30 is arranged.
The inlet 24 is located laterally at the top on the housing 12. The outlet 26 is located laterally at the conical bottom 22. The optional return line 28 connects the outlet 26 with the inlet 24. At the conical bottom 22 the removal device 30 is arranged.
[0048] The phosphate-containing liquid 14 flows through the inlet 24 from the top to the bottom through the reactor 10 and exits from it through the outlet 26.
Precipitated phosphate salts are removed via the removal device 30 without affecting the operation of the reactor. By means of return line 28 the already purified liquid 14 is supplied again to the reactor 10 as circulating water.
Precipitated phosphate salts are removed via the removal device 30 without affecting the operation of the reactor. By means of return line 28 the already purified liquid 14 is supplied again to the reactor 10 as circulating water.
[0049] Figure 5 shows a further embodiment of the reactor 10 according to the invention. In this way, the reactor 10 is flowed through in downward direction. The inlet 24 is located laterally at the top at the housing 12.
The outlet 26 is located at the bottom end at the conical bottom 22 and extends from there to a downstream filter 31. The optional return line 28 connects the outlet 26 with the inlet 24.
The outlet 26 is located at the bottom end at the conical bottom 22 and extends from there to a downstream filter 31. The optional return line 28 connects the outlet 26 with the inlet 24.
[0050] In this fourth embodiment according to the invention, the precipitated phosphate salts are removed together with the purified liquid 14 from the reactor 10. In the downstream filter 31 the phosphate salts are separated from the liquid 14. In this context there is the possibility to supply seed crystals to the reactor 10 via the return line 28.
[0051] In Figure 6, an application of the reactor 10 according to the invention in connection with producing biogas from phosphorus-containing wastewater is schematically illustrated.
[0052] A wastewater flow 32 of organic origin is supplied to a bioreactor 34.
Herein, by anaerobic fermentation processes, the organic carbon compounds that are contained in the solids are converted into biogas and mineral residual substances. In this process, ammonium-containing and phosphate-containing process water 36 is produced. Before the process water 36 is supplied through inlet 24 into the reactor 10, possibly contained solids 40 are separated in a filter 38. The solids 40 which are retained in the filter 38 are returned into the bioreactor 34. In the afore described way, in the reactor 10 according to the invention the phosphate salts are separated. The ammonium-containing and phosphate-containing oufflow 26 can be returned partially into the bioreactor 34. In this way, an impairment of the fermentation process, caused by a high ammonium concentration, is prevented.
Herein, by anaerobic fermentation processes, the organic carbon compounds that are contained in the solids are converted into biogas and mineral residual substances. In this process, ammonium-containing and phosphate-containing process water 36 is produced. Before the process water 36 is supplied through inlet 24 into the reactor 10, possibly contained solids 40 are separated in a filter 38. The solids 40 which are retained in the filter 38 are returned into the bioreactor 34. In the afore described way, in the reactor 10 according to the invention the phosphate salts are separated. The ammonium-containing and phosphate-containing oufflow 26 can be returned partially into the bioreactor 34. In this way, an impairment of the fermentation process, caused by a high ammonium concentration, is prevented.
Claims (11)
1. A reactor for complete crystallization and recovery of magnesium ammonium phosphate (MAP) and potassium magnesium phosphate (PMP) from a liquid and for recovery of phosphate salts, comprising a housing and two electrodes of different polarity, wherein a sacrificial anode of a magnesium-containing material and an inert cathode are arranged concentrically within the housing, and seed crystals are supplied to the reactor via a return line, wherein the reactor comprises an inlet, an outlet, and a removal device for removal of precipitated phosphate salts.
2. The reactor according to claim 1, wherein the housing is manufactured of an electrically conducting material and serves as the inert cathode.
3. The reactor according to any one of claims 1-2, wherein the sacrificial anode is substantially comprised of magnesium.
4. The reactor according to claim 1, wherein the return line branches off the outlet or the removal device.
5. The reactor according to any one of claims 1-4, wherein the reactor is flowed through in vertical direction from the bottom to the top.
6. The reactor according to any one of claims 1-4, wherein the reactor is flowed through in vertical direction from the top to the bottom.
7. The reactor according to any one of claims 1-6, wherein the crystals are separated in a filter from the liquid.
8. The reactor according to any one of claims 1-7, wherein the housing of the reactor is closed.
9. The reactor according to any one of claims 1-7, wherein the housing of the reactor is open.
10. The reactor according to any one of claims 1-9, wherein the reactor has a slanted bottom.
11. The reactor according to any one of claims 1-10, wherein to the sacrificial anode a positive pole and to the cathode a negative pole of a direct current source are connected.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE102010050692A DE102010050692B3 (en) | 2010-11-06 | 2010-11-06 | Reactor for the recovery of phosphate salts from a liquid |
DE102010050692.3 | 2010-11-06 | ||
PCT/EP2011/069119 WO2012059465A1 (en) | 2010-11-06 | 2011-10-31 | Reactor for recovering phosphate salts from a liquid |
Publications (2)
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CA2815914A1 CA2815914A1 (en) | 2012-03-10 |
CA2815914C true CA2815914C (en) | 2017-07-25 |
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Application Number | Title | Priority Date | Filing Date |
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CA2815914A Active CA2815914C (en) | 2010-11-06 | 2011-10-31 | Reactor for recovering phosphate salts from a liquid |
Country Status (8)
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US (1) | US20130228457A1 (en) |
EP (1) | EP2635534B1 (en) |
BR (1) | BR112013011181A2 (en) |
CA (1) | CA2815914C (en) |
DE (1) | DE102010050692B3 (en) |
DK (1) | DK2635534T3 (en) |
RU (1) | RU2013124995A (en) |
WO (1) | WO2012059465A1 (en) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
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DE102012220810B3 (en) | 2012-11-14 | 2014-02-13 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Process for increased phosphorus recovery from organic residues |
EP2937131B1 (en) * | 2012-12-19 | 2018-04-04 | Fuji Electric Co., Ltd. | Exhaust gas purifying apparatus |
DE102014207842C5 (en) | 2014-04-25 | 2018-05-17 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Combined recovery of phosphorus, potassium and nitrogen from aqueous residues |
DE102015215037B4 (en) | 2015-08-06 | 2021-02-25 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Reactor with sacrificial anode |
DE102016109824A1 (en) | 2016-05-27 | 2017-11-30 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Electrolytic reactor comprising a cathode and an anode |
DE102016109822A1 (en) | 2016-05-27 | 2017-11-30 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Electrolytic reactor |
DE102016115554A1 (en) | 2016-08-22 | 2018-02-22 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Plant for the production of phosphate salts and biological wastewater treatment plant and process for the operation of these plants |
EP3375760A1 (en) | 2017-03-13 | 2018-09-19 | Joachim Clemens | Method for the precipitation of phosphorous and sodium in waste water |
DE102019108832A1 (en) | 2019-04-04 | 2020-10-08 | Antonia Hollerbach | Process for wastewater treatment |
US20240025776A1 (en) * | 2020-08-14 | 2024-01-25 | The Board Of Trustees Of The Leland Stanford Junior University | Systems and Methods of Flexible Electrochemical Stripping to Recover Alkaline Ammonia and Acidic Ammonium from Wastewaters |
DE102021127350A1 (en) | 2021-10-21 | 2023-04-27 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung eingetragener Verein | Electrolytic Reactors |
Family Cites Families (16)
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US2724688A (en) * | 1952-04-29 | 1955-11-22 | John W Gruner | Process of growing crystals of aluminum phosphate |
US3635764A (en) * | 1969-01-02 | 1972-01-18 | Gen Electric | Combined wastewater treatment and power generation |
US3607688A (en) * | 1969-01-17 | 1971-09-21 | Seiichi Inoue | Treating sea water with production of chlorine and fertilizer |
US3840365A (en) * | 1970-04-24 | 1974-10-08 | P Kayser | Metal recovery process |
US3964991A (en) * | 1975-07-28 | 1976-06-22 | Canton Textile Mills, Inc. | Method and apparatus for precipitating colloids from aqueous suspensions |
US4378276A (en) * | 1980-02-01 | 1983-03-29 | Liggett James J | Electrolytic treatment of water |
US4808282A (en) * | 1987-01-05 | 1989-02-28 | The Dow Chemical Company | Alkaline earth metal compounds and alkali metal substances via electrochemical process |
AU6929894A (en) * | 1993-06-01 | 1994-12-20 | Phostrip-Abwasser-Technik Gmbh | Electrochemical treatment process and device for calcium- and/or magnesium-containing water or waste water |
EP1084993A1 (en) | 1999-09-14 | 2001-03-21 | Eco Flanders S.A. | Device for processing manure |
DE10112934B4 (en) | 2001-03-12 | 2004-08-26 | Berliner Wasserbetriebe Anstalt des öffentlichen Rechts | Procedures for avoiding and removing incrustations when pumping and draining liquids |
US6887368B2 (en) * | 2002-09-25 | 2005-05-03 | Ural Process Engineering Company, Ltd. | Method and device for electroextraction of heavy metals from technological solutions and wastewater |
ES2440655T3 (en) * | 2004-05-20 | 2014-01-29 | Elm Inc. | Water purifier |
DE102005034138A1 (en) | 2005-07-19 | 2007-01-25 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Reactor for recovering magnesium ammonium phosphate and process for recovering magnesium ammonium phosphate from manure or ammonia-containing waste gases |
EP1946821A1 (en) * | 2005-10-27 | 2008-07-23 | Nisshinbo Industries, Inc. | Method for producing fine particles of salt, hydroxide or oxide, and fine particles of salt, hydroxide or oxide produced by such method |
DE102006060365A1 (en) * | 2006-12-15 | 2008-06-19 | Technische Fachhochschule Berlin | Method for reducing phosphate content of liquid e.g. waste water, comprises applying an electrical direct current voltage to two inert electrodes present in the liquid and transferring loaded fine dispersed or colloidal phosphate particles |
DE102007061561A1 (en) * | 2007-12-18 | 2009-06-25 | Magontec Gmbh | Galvanic sacrificial anode useful in a storage device for aqueous media such as drinking water, comprises a magnesium based alloy consisting of aluminum, zinc, manganese, strontium and other impurities |
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2010
- 2010-11-06 DE DE102010050692A patent/DE102010050692B3/en active Active
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- 2011-10-31 DK DK11779163.2T patent/DK2635534T3/en active
- 2011-10-31 US US13/883,586 patent/US20130228457A1/en not_active Abandoned
- 2011-10-31 RU RU2013124995/05A patent/RU2013124995A/en not_active Application Discontinuation
- 2011-10-31 EP EP11779163.2A patent/EP2635534B1/en active Active
- 2011-10-31 WO PCT/EP2011/069119 patent/WO2012059465A1/en active Application Filing
- 2011-10-31 BR BR112013011181A patent/BR112013011181A2/en not_active IP Right Cessation
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DK2635534T3 (en) | 2017-01-02 |
US20130228457A1 (en) | 2013-09-05 |
WO2012059465A1 (en) | 2012-05-10 |
BR112013011181A2 (en) | 2016-08-02 |
EP2635534A1 (en) | 2013-09-11 |
EP2635534B1 (en) | 2016-09-21 |
CA2815914A1 (en) | 2012-03-10 |
DE102010050692B3 (en) | 2012-03-22 |
RU2013124995A (en) | 2014-12-20 |
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