KR101004067B1 - System for recovering posphate and method for recovering posphate using the same - Google Patents

Abstract

Provided are a facility for recovering phosphorus from sewage and a method for recovering phosphorus using the same. The phosphorus recovery facility includes a biological reaction means including an anaerobic tank, a first membrane separation means for separating slurries in the effluent from the anaerobic tank, and a first precipitation means for coagulating and precipitating phosphorus in the effluent from the membrane separation means. According to the phosphorus recovery facility and phosphorus recovery method of the present invention can remove high-quality phosphorus by removing impurities from the excessively discharged phosphorus in the biological advanced treatment process of sewage without additional external carbon source, it is possible to increase the utilization of wastewater have. In addition, it can be applied to any modification process of the advanced treatment method, and there is no restriction in the application of the existing process because the required site, such as the flocculation and inclined plate sedimentation basin including the membrane separation process is small.

Wastewater, phosphorus, anaerobic tank, excess

Description

Phosphorus recovery facility and phosphorus recovery method using the same {SYSTEM FOR RECOVERING POSPHATE AND METHOD FOR RECOVERING POSPHATE USING THE SAME}

The present invention relates to a phosphorus recovery facility and a phosphorus recovery method using the same, and more particularly, to a facility for recovering phosphorus from sewage water and a phosphorus recovery method using the same.

Efficient removal of phosphorus from sewage is by converting phosphorus into biological solids (microorganisms) or by converting it into chemical precipitates.

The conversion to biological solids is by using advanced sewage and wastewater treatment processes. Phosphorus is removed by excessive intake of phosphorus in an aerobic state and by disposing of excess sludge with high phosphorus content.

In this advanced treatment process, the phosphorus removal is performed by disposing of excess sludge in the water treatment process as excess sludge. Therefore, in order to increase the phosphorus removal efficiency, a complicated physicochemical follow-up process should be configured.

On the other hand, the postrip process (Phostrip process) to remove the phosphorus in the sludge treatment process can be more efficient phosphorus removal by using a combination of biological phosphorus removal and chemical treatment. However, in the post-lip process, the maintenance cost of the process increases because a separate external carbon source must be supplied to the dephosphorization tank in order to release excess phosphorus.

Therefore, there has been a need for a method capable of efficiently recovering phosphorus, while efficiently removing phosphorus and maintaining the process, and not treating phosphorus as a simple treatment target.

Accordingly, the present invention is to provide a facility that can effectively recover phosphorus from sewage.

In addition, the present invention is to provide a method for effectively recovering phosphorus from sewage.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

Phosphorus recovery facility according to an embodiment of the present invention is a biological reaction means including an anaerobic tank, the first membrane separation means for separating the slurry in the effluent containing excess phosphorus from the anaerobic tank, and the excess from the membrane separation means And a first precipitation means for coagulating and precipitating phosphorus in the treated water containing phosphorus.

In the phosphorus recovery facility, the first membrane separation means may be a vortex generating membrane separation means.

In addition, the first precipitation means in the phosphorus recovery facility may be a gradient plate settling tank.

In addition, the phosphorus recovery facility may further comprise a second precipitation means for precipitation of foreign matter in the treated water from the biological reaction means.

In addition, the phosphorus recovery facility may further comprise a second membrane separation means for separating the foreign matter in the treated water from the biological reaction means, the second membrane separation means may be located outside or inside the biological reaction means. Can be.

The phosphorus recovery method according to an embodiment of the present invention comprises the steps of removing the slurry in the effluent containing excess phosphorus released by anaerobic digestion of sewage, and in the treated water comprising excess phosphorus from which the slurry has been removed Recovering the phosphorus;

In the phosphorus recovery method, the slurry removing step may use vortex generating membrane separation means.

In the phosphorus recovery method, the phosphorus recovery step may use a gradient plate settling tank.

In addition, the phosphorus recovery method may be recovered by agglomeration of the phosphorus using the phosphorus recovery step flocculant, wherein the flocculant includes at least one selected from polyvalent metal ions such as calcium ions, aluminum ions, and iron ions. can do.

According to the phosphorus recovery facility and phosphorus recovery method of the present invention can remove high-quality phosphorus by removing impurities from the excessively discharged phosphorus in the biological advanced treatment process of sewage without additional external carbon source, it is possible to increase the utilization of wastewater have. In addition, it can be applied to any modification process of the advanced treatment method, and there is no restriction in the application of the existing process because the required site, such as the flocculation and inclined plate settler, including the membrane separation process is small.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, a phosphorus recovery facility according to an embodiment of the present invention will be described with reference to FIG. 1. 1 is a block diagram schematically illustrating a phosphorus recovery facility according to an embodiment of the present invention.

As shown in FIG. 1, the phosphorus recovery facility according to the exemplary embodiment of the present invention includes a biological reaction tank 100 including an anaerobic tank 110, a membrane separation means 200, a first precipitation means 300, and a first It consists of two precipitation means (400).

The biological reaction means 100 serves to decompose and remove organic matter by reacting the incoming wastewater with microorganisms.

The biological reaction means 100 may include a combination of reaction tanks such as an anaerobic tank 110, an anoxic tank 120, an aerobic tank 130, and the like, although not shown in view of decomposition efficiency of organic matter, residence time, etc. 120), an aerobic tank 130, etc. may be included in multiple numbers.

Phosphorus release occurs in the anaerobic tank 110 of the biological reaction means 100. In the anaerobic tank 120 adjacent to the anaerobic tank 110 described above, nitrous acid and nitric acid in the wastewater are converted to nitrogen gas using denitrifying microorganisms and removed.

In the aerobic tank 130 adjacent to the anoxic tank 120, organic matter in the wastewater is decomposed into carbon dioxide and water using aerobic microorganisms, and ammonia nitrogen is nitrified to nitrous acid or nitric acid using nitric oxide microorganisms.

In addition, the phosphorus recovery facility according to an embodiment of the present invention includes a membrane separation means 200 for removing the sludge from the effluent containing excess phosphorus from the anaerobic tank 110 of the biological reaction means (100).

Effluent and sludge from the anaerobic tank 110 is present in a mixed state, which is difficult to remove only by a simple separation process. For example, sedimentation or pressure concentration may cause problems in maintenance, such as sludge rising to the top of the reactor to form a scum. Therefore, the most effective method of separating the sludge is to use a membrane separation means, the sludge is attached to the surface of the separation membrane may be clogged phenomenon occurs. The phosphorus recovery facility according to an embodiment of the present invention includes a vortex generating membrane separation means as the membrane separation means. Vortex means that the fluid flows while swirling, and vortex in the present specification is meant to include turbulent flow unless otherwise specified.

Vortex generating membrane separation means will be described in more detail with reference to FIGS. Figure 2 is a cross-sectional view showing an example of the vortex generating membrane separation means included in the phosphorus recovery facility according to an embodiment of the present invention, Figure 3 is a perspective view showing a rotor for generating a vortex in the membrane separation device, 4 is a cross-sectional view taken along the line IV-IV 'of FIG. 3.

As shown in FIG. 2, the vortex generation membrane separation means is treated with an inlet 212 through which the effluent water containing excess phosphorus and slurry from the anaerobic tank (110 in FIG. 1) is introduced, and the excess phosphorus from which the slurry has been removed. A barrel 210 having a discharge port 214 for discharge of water, a discharge port 216 for discharging the concentrated water containing the slurry, and a rotor 220 for generating a vortex and a slurry installed in the barrel 210 to filter the slurry And a filter tray 230.

As shown in FIG. 3, among the vortex generating membrane separation means, the vortex generating rotor 220 is connected to a motor (not shown) to generate vortices when the motor is rotated. The first rotor 222 and the second rotor It consists of 226. Here, the first rotor 222 has a plurality of first blades 224 extending radially about the rotation axis, the second rotor 226 extends in the radial direction about the rotation axis, The 1st blade 224 is provided with the some 2nd blade 228 arrange | positioned in a different position on the rotation axis direction.

Referring back to FIG. 1, the phosphorus recovery facility according to an embodiment of the present invention includes a first precipitation means 300 for precipitation of phosphorus in the treated water from the membrane separation means 200. The first precipitation means 300 is to precipitate the phosphorus in the treated water including excess phosphorus from which the sludge is removed, for example, may be a gradient plate settling tank.

Inclined plate sedimentation tank is a device that improves the water quality by sedimentation of suspended matter heavier than water by gravity. In general, sedimentation of single particles in a gradient plate settling tank is known to be directly related to the settling rate, regardless of the depth of the tank. In order to optimize the flotation removal efficiency of the settling tank, the surface area of the settling tank should be properly designed as much as possible. Inclined plate sedimentation tank is widely used because of the excellent precipitation effect of the suspended solids based on the above analysis. This inclined plate settling tank is used to form a multi-layered inclined tube (sedimentation channel) using the inclined plate in the settling tank to increase the settling efficiency. As the inclined plate settling tank is formed by the inclined tube (sedimentation channel) by the multi-layered inclined plate, the overall settling distance can be kept short, so that the settling process can be speeded up, and in addition, there is an advantage in discharge of the sediment required for the settling process.

In addition, another phosphorus recovery facility in one embodiment of the present invention includes a second precipitation means 400 for removing foreign matter in the treated water from the biological reaction means 100 once more.

Subsequently, a phosphorus recovery facility according to another embodiment of the present invention will be described with reference to FIGS. 5 and 6. 5 and 6 are block diagrams schematically illustrating phosphorus recovery facilities according to another embodiment of the present invention.

As shown in Figure 5 and 6, the phosphorus recovery facility according to an embodiment of the present invention is biological reaction means 100, membrane separation means 200, agent of the phosphorus recovery facility according to an embodiment of the present invention The biological reactor 100, the first membrane separation means 200, the precipitation means 300, and the second membrane separation means 500, 600, which include an anaerobic tank 110, which are substantially the same as the first precipitation means 300, It is made to include.

The second membrane separation means 500 and 600 are for removing the foreign matter in the treated water from the biological reaction means 100 once more. The second membrane separation means 500 and 600 may include various filtration membranes according to the size of the foreign material to be removed, and the filtration membrane may include, for example, a microfiltration membrane, an ultrafiltration membrane, and a nanofiltration membrane. (nanofiltration membrane) or reverse osmosis membrane (Reverse Osmosis membrane) can be used. In addition, the second membrane separation means 500 and 600 may use one filtration membrane, or may be used in combination of one or more filtration membranes, although not illustrated.

As described above, the second membrane separation means 500 and 600 may be located outside the biological reaction means 100 as shown in FIG. 5, and the biological reaction means 100 as shown in FIG. 6. It may be located inside, more preferably in the aerobic tank 130 of the biological reaction means 100.

Subsequently, a phosphorus recovery method according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4 and 7 to 9. 7 is a process flow chart showing a phosphorus recovery method according to an embodiment of the present invention in a process order, Figure 8 is a graph showing the concentration of phosphorus in the reaction tank for each process when removing the biological phosphorus, Figure 9 is Figure 3 It is a figure which shows the eddy current produced by the operation | movement of the rotor shown in FIG. Hereinafter, a method of recovering phosphorus using a phosphorus recovery facility according to an embodiment of the present invention as shown in FIG. 1 will be described, but the present invention is not limited to the above-described phosphorus recovery facility.

First, as shown in FIG. 7, the slurry in the effluent containing phosphorus discharged by anaerobic digestion of wastewater is removed (S1).

Referring to FIG. 1, wastewater containing a high concentration of organic matter is introduced into the anaerobic tank 110 of the biological reactor 100. The soluble BOD in the water is converted into acetate or other forms of short chain fatty acid by the optional microorganism in the anaerobic tank 110. These short-chain fatty acids are degraded by microorganisms such as Bio-P or Poly-P in the anaerobic tank 110, which are generated by the hydrolysis of polyphosphate stored in cells. Excess phosphorus is released into the wastewater using energy, and short-chain fatty acids are stored in cells as polyhydroxybutyrate. The change in the phosphorus content in the biological reactor 100 is as shown in FIG.

As described above, the wastewater containing excess phosphorus is sent from the anaerobic tank 110 to the membrane separation means 200. The membrane separation means 200 may preferably be a vortex generating membrane separation means.

3, 4, and 9, first, the wastewater containing excess phosphorus from the anaerobic tank 110 (in FIG. 1) is introduced into the inlet 212. The wastewater introduced into the barrel 210 passes through the separation membrane of the filter tray 230, and sludge contained in the wastewater is filtered out, and part of the wastewater is discharged through the outlet 214 as treated water containing excess phosphorus. Outflow to the precipitation means (300 in FIG. 1).

In the vortex generating membrane separation means, the rotor 220 is continuously rotated by a motor (not shown) that rotates about a rotation axis while the purging operation is performed, and the first blade 224 as shown in FIG. 3. ) And the second blade 228 are disposed at mutually different positions in the circumferential direction around the rotation axis of the rotor 220 to generate a complicated type of vortex as shown in FIG. 9 when the rotor 220 is rotated. .

By removing the sludge adhering to the separation membrane of the filter tray 230 by the vortex, the removed sludge is discharged to the outside of the barrel 210 through the brine outlet 216 in a state of being contained in the brine, the first precipitation Out of the means (300 in FIG. 1).

Therefore, as described above, it is possible to effectively remove the sludge fixed to the separation membrane of the filter tray 230 by using the vortex.

Next, with reference to FIG. 7 again, phosphorus in the treated water from which the slurry was removed is recovered (S2).

First, in order to crystallize excess phosphorus contained in the treated water from the membrane separation means (200 in FIG. 1), chemicals are added in proportion to the amount of phosphorus in the treated water to aggregate the phosphorus, and the first precipitation means 300 ), Preferably by precipitation in a slop plate precipitation means to recover phosphorus.

Agglomeration of phosphorus occurs by adding a polyvalent metal ion salt. The most widely used polyvalent metal ions are calcium ions (Ca ^{2 +} ), aluminum (Al ^{3 +} ) and iron (Fe ^{3 +} ), for example lime (Ca (OH) ₂ ), alumina (Al ₂ O ₃ ), Sodium aluminate (NaAlO ₂ ), ferric chloride (FeCl ₃ ), ferric sulfate (Fe ₂ (SO ₄ ) ₃ ), ferric sulfate (FeSO ₄ ), ferric chloride (FeCl ₂ ), and the like.

When a polymer coagulant is used as a coagulation aid together with such polyvalent metal ions, the coagulation efficiency of phosphorus can be further improved. In order to obtain a high treatment efficiency, the polyvalent metal ions and flocculent aids described above may be used in excess of theoretical amounts.

In addition, when the excess phosphorus in the treated water is reacted with calcium to coprecipitate, aggregation efficiency and economic effect can be obtained. As a metal salt for reacting phosphorus with calcium and coprecipitation, lime (Ca (OH) ₂ ), calcium carbonate (CaCO ₃ ), etc. can be used as a calcium source, for example. In the case of lime (Ca (OH) ₂ ) and calcium carbonate (CaCO ₃ ), as well as a source of calcium, it can serve as an adjuvant in forming phosphorus and insoluble precipitates, and can efficiently remove phosphorus in sewage water at low cost.

As described above, phosphorus recovered in the aggregated form is present in the form of aluminum phosphate (AlPO ₄ ) and hydroxyapatite (Ca ₅ (PO ₄ ) ₃ (OH)), and does not contain impurities. When used as a high-quality fertilizer, because of high productive value and high purity, it is widely used in various fields.

Referring again to FIG. 1, the treated water from which excess phosphorus has been removed is sent to the oxygen-free tank 120 and the aerobic tank 130 of the biological reaction means 100, respectively, to remove nitrogen in a conventional manner. In more detail, in the anoxic tank 120, when decomposing under anoxic conditions without molecular oxygen (free oxygen), the nitrate nitrogen is reduced to nitrogen gas by using the bound oxygen in the nitrate molecule as the final electron acceptor instead of free oxygen. Nitrogen is removed from the effluent and the aerobic tank 130 decomposes organic matter into carbon dioxide gas and water, and nitrogen compounds into ammonia and nitrate by metabolism of aerobic microorganisms.

The treated water from the biological reaction means 100 as described above is discharged to the outside after the foreign matter is further removed from the second precipitation means, the concentrated water containing the foreign matter is introduced into the new wastewater and the biological reaction means 100 again Thus, the phosphorus recovery process as described above is repeated.

According to the phosphorus recovery method according to an embodiment of the present invention as described above, not only the wastewater treatment method containing phosphorus is simple, but also compared with the conventional biological phosphorus recovery method, the characteristics (carbon / phosphorus) and properties of the wastewater It is possible to obtain high treatment efficiency regardless of (NO ₃ ^- presence), and high treatment efficiency can be obtained with a small amount of chemical compared with the conventional biological advanced treatment method. In particular, the phosphorus recovered by the phosphorus recovery method according to an embodiment of the present invention is present in the form of aluminum phosphate (AlPO ₄ ) and hydroxyapatite (Ca ₅ (PO ₄ ) ₃ (OH)), including impurities Because it is not, high quality fertilizer has high productivity value and high purity, so it is widely used in various fields.

In the above described exemplary embodiments of the present invention by way of example, the scope of the present invention is not limited to the specific embodiments as described above, the patent of the present invention by those skilled in the art to which the present invention belongs Changes may be made as appropriate within the scope of the claims.

1 is a block diagram schematically illustrating a phosphorus recovery facility according to an embodiment of the present invention.

2 is a cross-sectional view showing an example of the vortex generating membrane separation means included in the phosphorus recovery facility according to an embodiment of the present invention.

3 is a perspective view showing a vortex generating rotor in the membrane separation device.

4 is a cross-sectional view taken along the line IV-IV 'of FIG. 3.

5 and 6 are block diagrams schematically illustrating phosphorus recovery facilities according to another embodiment of the present invention.

7 is a process flowchart showing a phosphorus recovery method according to an embodiment of the present invention in the order of process.

8 is a graph showing the phosphorus concentration in the reaction tank for each process during biological phosphorus removal.

FIG. 9 is a diagram showing a vortex generated by the operation of the rotor shown in FIG. 3.

Claims (12)

Biological reaction means including an anaerobic tank; First membrane separation means for separating sludge in the effluent containing excess phosphorus from said anaerobic tank; First precipitation means for coagulating and precipitating phosphorus in the treated water including excess phosphorus from said membrane separation means; And A second membrane separation means for separating foreign matter in the treated water treated by the biological reaction means, The second membrane separation means is located within the biological reaction means, Wherein said first membrane separation means corresponds to a vortex generating membrane separation means. The method of claim 1, And said second membrane separation means comprises at least one filtration membrane. The method of claim 1, And the first precipitation means is an inclined plate precipitation tank. The method of claim 2, Wherein said at least one filtration membrane comprises at least one of a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane and a reverse osmosis membrane. The method of claim 1, The biological reaction means further includes an anoxic tank and an aerobic tank, And said second membrane separation means is located within said aerobic tank. delete Reacting the wastewater with microorganisms using a biological reaction means to decompose / remove organic matter; Separating foreign substances in the treated water from which the organic matter is decomposed / removed; Removing sludge in the effluent comprising excess phosphorus released by anaerobic digestion by the anaerobic tank in the biological reaction means; And Recovering said phosphorus in treated water comprising excess phosphorus from which said sludge has been removed, Separating the foreign matter is performed by a second membrane separation means located inside the biological reaction means, Removing the sludge is carried out by the vortex generating membrane separation means. The method of claim 7, wherein The biological reaction means includes an anoxic tank and an aerobic tank, And the second membrane separation means is located inside the aerobic tank. The method of claim 7, wherein The phosphorus recovery step is a phosphorus recovery method using a gradient plate settling tank. The method of claim 7, wherein The phosphorus recovery step is to collect the phosphorus by using a flocculant to recover the phosphorus. The method of claim 10, And said coagulant is a polyvalent metal ion. The method of claim 11, The polyvalent metal ion is phosphorus recovery method comprising at least one selected from calcium ions, aluminum ions and iron ions.

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