KR101861072B1 - Sewage and wastewater treatment system with crystallization apparatus for phosphorus recovery - Google Patents

Abstract

The present invention relates to a facility for treating food waste or livestock manure that is introduced, and in the present invention, there is provided a pretreatment tank for removing foreign matter or soil from imported food waste and livestock manure, a digester for digesting sludge through a pretreatment tank, A digestion concentrator for receiving and digesting digested sludge from the digester, a phosphorus crystallization device for introducing the supernatant from the digestion concentrator, adding a pH control solution to adjust pH, and introducing a crystallization agent to produce phosphorus crystals And a food waste disposal facility is provided.

Description

TECHNICAL FIELD [0001] The present invention relates to a wastewater treatment facility and a food wastewater treatment facility having a crystallization apparatus,

The present invention relates to a wastewater treatment facility having a phosphorus crystallization apparatus and a food waste / livestock manure treatment facility, and more particularly, to a wastewater treatment facility having a phosphorus crystallization from a reflux water containing a high concentration phosphorus generated in a biological advanced treatment facility Wastewater treatment facility and food waste / livestock manure treatment facility having a phosphorus crystallization device for improving useful factor source recovery, sludge reduction and phosphorus treatment efficiency.

The reflux water generated from the concentrating tank, anaerobic digestion tank and dehydrator of the biological advanced treatment facility contains high concentration of nitrogen and phosphorus and is not appropriately treated. If the nutrient concentration exceeds a certain level, eutrophication phenomenon is caused And is conveyed and processed in a water treatment process.

Biological advanced treatment facilities are divided into nitrogen removal and phosphorus removal processes. The nitrogen removal process consists of an aerobic and anaerobic reaction tank. In the aerobic condition, ammonia is oxidized to nitrite or nitrate nitrogen by nitrifying bacteria. In the next process, anaerobic condition, denitrification bacteria oxidize BOD, which is an electron donor, The nitrogen compound is reduced and removed by the nitrogen gas. In such a biological nitrogen removal process, ammonia nitrogen is known to be relatively stable.

On the other hand, the phosphorus removal process is composed of an anaerobic and aerobic reaction tank, and utilizes the physiological characteristics of the phosphorus removal microorganisms storing phosphates in the form of polyphosphates in the cells. In anaerobic conditions, the phosphorus-removing microorganisms decompose the polyphosphoric acid accumulated in the cells into phosphates and release them out of the cell. In this process, a large amount of energy is generated. By using this energy, BOD is taken from the sewage and the biodegradable polymer Polyhydroxybutyrate (PHB) is synthesized and stored. Phosphorus-free microbes under aerobic conditions produce energy using PHB stored in cells and take phosphates into cells and store them as polyphosphates. Removal of microorganisms accumulating polyphosphoric acid in the sludge form in the final sedimentation tank of the biological advanced treatment process removes phosphorus from sewage.

FIG. 1 is a process block diagram of a conventional wastewater treatment facility. Referring to FIG. 1, the inflow water 1 of influent wastewater and sewage is introduced into the gravel bed 10 and is firstly precipitated in the first settler 20 , The microorganisms are used in the bioreactor 30, then precipitated in the secondary settler 50, and then discharged to the effluent 100. At this time, it is also possible to adopt a method of adding a filter paper to the step after the second settling paper 50 and the step before discharging to filtrate and discharge. The debris generated in the primary settler 20 in the process of treating such waste water is referred to as raw sludge, and the debris generated in the secondary settler 50 is referred to as excess sludge. Among these sludge and excess sludge, The digestion tank 60, the digestion tank 70, the digestion and concentration tank 80, and the dehydrator 90 in this order, followed by concentration, digestion, and dehydration.

At this time, the concentration tank supernatant, the digester tank supernatant, and the dehydration filtrate, which are generated in the sludge treatment process, are referred to as counter currents. The counter currents are then sent back to the front of the primary settler 20 for reprocessing. However, since the amount of the reflux water generated in the sludge treatment process is relatively small compared with the total influent flow rate, the conventional method of treating the waste water and wastewater causes an impact load on the water treatment system because it contains high concentrations of nitrogen and phosphorus. .

As in Korea, chemical treatment is often used in sewage with relatively low BOD concentration compared to nitrogen or phosphorus because of the inherent disadvantage of the biological advanced treatment process, which is difficult to remove to a level that can prevent eutrophication. Furthermore, since the reflux water containing the high concentration of phosphorus generated in the concentrating tank, the anaerobic digestion tank and the dehydration facility of the sludge treatment process is conveyed and processed in the water treatment process, the deterioration of the phosphorus removal ability due to the increase in phosphorus load is a serious problem Is emerging.

Generally, the sludge generated in the biological treatment process is processed through a separate sludge treatment process, and anaerobic digestion is mainly used for energy production as well as sludge treatment. The anaerobic digestion is characterized by hydrolysis and fermentation of sludge during digestion, organic acids are formed and methane is produced. During the hydrolysis of the sludge, the polyphosphoric acid accumulated in the microbial cells is hydrolyzed and eluted in the form of phosphate. Therefore, the supernatant and desalination of the sludge after anaerobic digestion process contain considerable high concentration of phosphate.

Recently, the efficiency of anaerobic digestion has been increased through the introduction of a thermal hydrolysis device in order to increase the treatment efficiency of the sludge and to increase the amount of methane generated, so that the concentration of total nitrogen and total phosphorus in the flotation water reaches hundreds to thousands of PPM. Therefore, the process of returning the reflux water generated in this process to the water treatment process without proper pretreatment is to remove the phosphorus in the anaerobic condition, so that the activated sludge having a low content of phosphorus is more effective than phosphorus Due to the limitations of microbial uptake capacity, it is difficult to meet current water quality standards for effluent sewage treatment plants.

Most of the biological high - altitude treatment processes in Korea currently treat phosphorus using chemical methods to compensate for these disadvantages. However, there is a need for an alternative because the cost of treatment of chemicals and sludge increases the high treatment cost.

Furthermore, phosphorus is a waste of resource because it has finite resources and can not be recovered and is disposed of. Phosphorus, which is included in agricultural and fishery products and seafoods, which are increasing in imports every year, is finally discharged through drainage through human bodies and livestock, etc., but is not recovered properly at the wastewater treatment facility and discharged into the public waters. . Therefore, it is necessary to recover the resources that can not be appropriately recovered at the sewage disposal site and to reclaim the resources that are being abandoned in the land, to enhance active coping ability with depleted resources and to prevent eutrophication of public water bodies.

Therefore, the crystallization method is the most practical and economical method to improve phosphorus removal efficiency and recovery of phosphorus in biological advanced treatment facilities. Crystallization methods include crystallization methods such as magnesium ammonium phosphate (MAP) and hydroxylapatite (HAP).

As a result of the above problems, it is necessary to develop a process for recovering phosphorus from the reflux water generated in the biological advanced treatment process to improve the phosphorus removal efficiency by reducing phosphorus load conveyed to the water treatment process, and recycling the recovered phosphorus as a resource. to be.

Patent Document 1: Korean Patent Registration No. 10-0837698 (Jun. 13, 2008) Patent Document 2: United States Patent Application Publication No. US2010 / 0170845 (Jul. 2010)

The present invention relates to a wastewater treatment facility and a wastewater treatment facility having a phosphorus crystallization device for efficiently recovering phosphorus from reflux water containing a high concentration phosphor by efficiently arranging apparatuses constituting a wastewater treatment facility and a food waste / And to provide food waste and livestock manure treatment facilities.

The present invention relates to a wastewater treatment facility having a phosphorus crystallization apparatus for recovering phosphorus, which is a useful resource, from reflux water containing a high concentration of phosphorus generated in a biological advanced treatment facility, It is intended to provide facilities.

Another object of the present invention is to provide a wastewater treatment facility and a food waste / livestock manure treatment facility having a phosphorus crystallization device for reducing the phosphorus load transferred to the water treatment process through phosphorus recovery to improve phosphorus removal efficiency .

SUMMARY OF THE INVENTION The object of the present invention is to provide a bioreactor for treating inflow water flowing from a primary clarifier with microorganisms, A sludge concentrating tank for concentrating excess sludge generated from a secondary sedimentation tank and a sludge concentrator for hydrolyzing the sludge introduced from the sludge concentration tank, A crystallization device for adding pH adjusting liquid to the sludge hydrolyzed in the thermohydrolysis device to adjust the pH and adding the crystallization agent to produce phosphorus crystals; a digester for digesting inflow water through the phosphorus crystallization device; A digestion and concentration tank for receiving and digesting digested sludge in a digestion tank, And a dehydrator for dewatering the concentrated sludge in the concentrating tank, wherein the desorption filtrate dehydrated in the dehydrator is introduced into the phosphorus crystallization apparatus.
SUMMARY OF THE INVENTION The object of the present invention is to provide a bioreactor for treating inflow water introduced from the primary clarifier with microorganisms, And a second settling tank for settling influent water flowing from the bioreactor, wherein the sludge concentration tank comprises a sludge concentration tank for concentrating the excess sludge generated from the secondary settling tank, a digester for digesting the sludge through the sludge concentration tank, A digestion concentrator for receiving digested sludge from a digestion tank and concentrating the digested sludge; at least a phosphorus-containing crystallizer for introducing a supernatant from a digestion-concentrating tank, adjusting pH by adding a pH control solution, Includes a dehydrator to dehydrate the concentrated sludge in the digestion tank And the desorption filtrate dehydrated in the dehydrator is introduced into the phosphorus crystallization apparatus. The crystallization apparatus comprises a crystallization storage vessel for temporarily storing inflow water to be introduced, and a crystallization storage vessel for storing the pH control solution and flowing in the inflow water flowing into the crystallization storage vessel a pH control liquid inlet for inputting a pH control liquid, a crystallization reaction tank for generating phosphate crystals from the influent water after the inflow water whose pH is controlled is introduced from the crystallization storage tank, and a chemical for producing phosphate crystals are stored in the crystallization reaction tank And a crystallization agent input unit for supplying a crystallization agent to the wastewater treatment facility.
The object of the present invention is to provide a food waste / livestock manure treatment facility including a pretreatment tank for removing foreign matters and soil from the food waste, livestock manure, and the like, comprising: a heat hydrolysis apparatus for hydrolyzing sludge through a pretreatment tank; A crystallization device for adding phosphorus to the sludge hydrolyzed in the hydrolysis device to adjust the pH of the sludge hydrolyzed to adjust the pH and adding crystallization chemicals to produce phosphorus crystals; And a dehydrator for dehydrating the concentrated sludge in the digester, wherein the desorption filtrate dehydrated in the dehydrator is introduced into the phosphorus crystallization apparatus, characterized in that phosphorus crystallization The apparatus comprises: a crystallization storage tank for temporarily storing inflow water to be introduced; A pH control liquid inlet for inputting a pH control liquid to the influent flowing into the storage tank; and a crystallization reaction tank for generating phosphate crystals from the influent water after the influent whose pH has been adjusted is introduced from the crystallization storage tank, And a crystallization reagent input unit for supplying the crystallization reagent into the crystallization reaction tank.
The object of the present invention is to provide a food waste and livestock manure treatment facility including a pretreatment tank for removing foreign matters and soil from the food waste and livestock manure that are introduced, A pyrolysis tank for receiving the sludge digested in the digester and concentrating the digested sludge; and a pyrolysis unit for introducing the pH-adjusting liquid into the pyrolysis tank, A crystallization storage tank for temporarily storing the influent water to be introduced, a pH control liquid inlet for storing a pH control liquid and inputting a pH control liquid to the influent water flowing into the crystallization storage vessel, And the phosphorus crystals are produced from the influent water. Storing a drug to produce the salt crystals can be achieved by the food waste, livestock waste treatment, characterized in that including a crystallization chemicals introduced to inject drug crystallization in the crystallization tank facilities.

According to the present invention having the characteristics as described above, it is possible to crystallize phosphorus from recycled water circulating in a water treatment process generated in a concentrating tank, an anaerobic digestion tank and a dehydrator of a biological advanced treatment facility, and recovering phosphorus to create added value.

In addition, it is possible to reduce the phosphorus load of the water treatment process finally, and it is possible to improve the water quality of the discharged water in the biological removal process, and it is possible to reduce the amount of chemicals required for the existing chemical treatment facility and greatly reduce the amount of sludge generated by the chemical treatment .

1 is a process block diagram of a conventional wastewater treatment facility.
2 is a process configuration diagram of a wastewater treatment facility according to an embodiment of the present invention;
3 is a modification of Fig.
4 is a process configuration diagram of a wastewater treatment facility according to an embodiment of the present invention.
5 is a modification of Fig.
6 is a process configuration diagram of a wastewater treatment facility according to an embodiment of the present invention.
Fig. 7 is a modification of Fig. 6; Fig.
Fig. 8 is a process configuration diagram when the present invention is applied to food waste disposal. Fig.
Fig. 9 is a process configuration diagram when the present invention is applied to livestock manure treatment. Fig.
10 is a device configuration diagram schematically showing the phosphorus recovery device of the present invention.
11 shows an embodiment of the crystallization reaction tank according to the present invention.

The present invention relates to a method for recovering phosphorus from recycled water containing high concentration of phosphorus generated in a wastewater treatment facility using an insoluble phosphate crystal phenomenon and recycling the phosphorus as a useful resource and further recycling the recovered phosphorus This study suggests the technical features that can improve phosphorus removal efficiency, reduce operation maintenance cost, and improve water quality of discharged water by reducing phosphorus load.

In the following, preferred embodiments, advantages and features of the present invention will be described in detail with reference to the accompanying drawings. In the following drawings, the solid line indicates the flow of the sewage including the supernatant, and the dotted line indicates the flow path of the sludge.

2 is a process configuration diagram of a wastewater treatment facility according to an embodiment of the present invention. The inflow water 1 of the inflow wastewater and sewage is introduced into the gypsum paper 10 to remove the gypsum and then the first settling is carried out in the first settling basin 20 and then the microorganism is treated in the bioreactor 30, Precipitated in the tea settling cell 50, and then discharged to the discharged water 100. At this time, it is also possible to adopt a method of adding a filter paper to the step after the second settling paper 50 and the step before discharging to filtrate and discharge.

The raw sludge 21 and the excess sludge 51 are introduced into the sludge concentration tank 60 and are concentrated and then digested in the digestion tank 70. The digested sludge is concentrated again in the digestion concentration tank 80, And then the desalination filtrate is introduced into the gravel bed 10 again. The sludge that has been dehydrated in the dehydrator 90 is disposed of through the waste company.

Generally, after completing a series of purification processes, the amount of the return water flowing back into the geyser 10 is about 1 to 2% of the inflow sewage amount and the residence time of the crystallization tank 120 is within 20 minutes. Therefore, the required area is small. Therefore, in a biological advanced treatment facility having a treatment capacity of 100 tons / day (day), the generation amount of the flushing water is about 1.5 tons, and the size of the reaction tank is 20 liters, which is about 19 minutes for the reaction time.

According to the experiment result of the inventor of the present invention, the concentration of phosphate in the reaction water contained in the supernatant 61 of the sludge concentration tank 60, the supernatant 81 of the digestion and concentration tank 80 and the dehydration filtrate 91 of the dehydrator 90 Were contained as shown in Table 1.

division Sludge thickener supernatant Digestion concentrate supernatant Dehydrated filtrate

17.5 (mg / l) 320 (mg / l) 9.5 (mg / l)

5% 92% 3%

As shown in Table 1, the concentration of phosphate contained in the supernatant 81 of the digestion and concentration tank 80 is controlled by the concentration of phosphate contained in the supernatant 61 of the sludge concentration tank 60 and the dehydration filtrate 91 of the dehydrator 90 As shown in Fig. That is, it can be confirmed that about 92% of phosphate contained in the reflux water of the conventional wastewater treatment facility shown in FIG. 1 is included in the digestion-enhancing tank supernatant.

Therefore, it is absolutely necessary to crystallize the phosphate contained in the supernatant 81 of the digestion-concentrating tank, and to form the crystallization filtrate into the reflux water among the components constituting the counter current. In the embodiment of FIG. 2, the pH of the digested thickener 80 is stored in the crystallization storage tank 110 for a predetermined period of time, the pH is adjusted through the pH adjusting solution inlet 130, The reaction solution is introduced into the reaction tank 120, the chemical is introduced through the crystallization agent input part 140 to produce phosphorus crystals, and the remaining filtrate is supplied as reflux water. 2, both the raw sludge 21 and the excess sludge 51 flow into the sludge concentration tank 60, so that the phosphate component contained in the supernatant 61 of the sludge concentration tank 60 is relatively high, ).

However, in some cases, as shown in Table 1, about 5% of the phosphate included in the total recirculated water is included in the supernatant 61 of the sludge thickener 60, But it is not preferable. 2, the desulfurization filtrate 91 forms the counter current. However, it is needless to say that the desulfurization filtrate 91 may also be input to the crystallization storage vessel 110 in order to more surely crystallize the phosphate.

Fig. 3 is a modification of Fig. 3 will be described only in terms of differences from the embodiment of FIG. 3, the raw sludge is directly introduced into the digester 70 without passing through the sludge thickening tank 60. The raw sludge (21) is mainly composed of organic matter due to its nature and has a high biodegradability and a low water content, and is directly introduced into the digester (70) without being concentrated. Therefore, only the surplus sludge 51 of the secondary settling tank 50 flows into the sludge concentration tank 60, so that the capacity of the sludge concentration tank can be minimized. On the other hand, since the raw sludge 21 composed of organic material flows directly into the digester 70 and is extinguished, the amount of phosphorus discharged from the sludge is greatly reduced because there is little organic matter flowing into the sludge concentration tank 60. Therefore, the supernatant of the sludge concentration tank 61 having a low concentration of phosphate can be transported to the water treatment process without flowing into the crystallization facility, thereby greatly reducing the capacity of the crystallization facility.

4 is a process configuration diagram of a wastewater treatment facility according to an embodiment of the present invention. 2 is characterized in that a thermal hydrolysis device 65 is further provided between the sludge thickening tank 60 and the digestion tank 70. The thermal hydrolysis device 65 is a device for maximizing the methane fermentation of the digester 70 and minimizing the amount of sludge generated and is a device for concentrating the sludge in the sludge concentration tank 60 under the conditions of high temperature (about 200 ^° C) Hydrolyze the sludge. In this process, since organic compounds such as proteins, polysaccharides, fats and celluloses are converted into simple organic substances that can be used in anaerobic digestion, the amount of methane generated in the digestion tank 70 can be greatly increased. Most of the polyphosphoric acid in the cell is decomposed into phosphate and released. The phosphate concentration is usually 1 g-P / L or more. The phosphoric acid concentration of the digestion-enhancing tank 80 supercritical fluid in which digestion sludge is concentrated due to microbial biosynthesis is removed at a digestion tank 70, which is a subsequent process of the thermohydrolysis device 65, It is. Therefore, phosphorus crystallization can maximize phosphorus recovery. To accomplish this, the mixed sludge of raw sludge and excess sludge concentrated in the sludge concentration tank (60) flows into the thermohydrolysis device (65), and the supernatant flows into the crystallization storage tank (110). The hydrolyzed sludge in the thermohydrolysis apparatus 65 is decomposed in the digester 70 and the generated digested sludge is separated from the supernatant 81 in the digestion and concentration tank 80. The concentrated digested sludge is dewatered to the dehydrator 90 and taken out to the sludge cake, and the desorption filtrate 91 generated at this time is introduced into the crystallization facility together with the supernatant 81 generated in the digestion and concentration tank 80. As described above, since the concentration of the phosphate contained in the desorption filtrate 91 is relatively low, it is possible to directly constitute the reflux water without flowing into the crystallization storage tank 110.

Fig. 5 is a modification of Fig. The configuration of FIG. 5 will be described only in the difference from the embodiment of FIG. 5, the raw sludge 21 is directly introduced into the digester 70 without passing through the sludge thickening tank 60. Therefore, the supernatant of the sludge concentration tank 61 having a low concentration of phosphate can be transported to the water treatment process without flowing into the crystallization facility, thereby greatly reducing the capacity of the crystallization facility.

6 is a process configuration diagram of a wastewater treatment facility according to an embodiment of the present invention. The influent water 1 flowing into the wastewater and the sewage is introduced into the gypsum paper 10 to remove the gypsum and the inflow water from which the gypsum is removed is firstly precipitated in the primary settler 20, And then precipitated in the secondary settler 50 and discharged to the discharged water 100. [ At this time, it is also possible to adopt a method of adding a filter paper to the step after the second settling paper 50 and the step before discharging to filtrate and discharge.

The raw sludge 21 and the excess sludge 51 are introduced into the sludge thickening tank 60 and concentrated, and then introduced into the thermal hydrolysis apparatus 65. The thermal hydrolysis apparatus 65 is operated to remove the concentrated sludge from the sludge concentration tank 60 under conditions of high temperature (about 150 ^° C) and high pressure (about 20 bar) to methane fermentation of the post- . The hydrolyzed sludge is in a liquid state and then sequentially flows into the crystallization storage tank 110 and the crystallization reaction tank 120 to be crystallized 150 and then digested in the digestion tank 70. The digested sludge in the digestion tank (70) is concentrated again in the digestion concentration tank (80) and dehydrated in the dehydrator (90). At this time, the supernatant liquid 81 and the desorption filtrate 91 of the digestion and concentration tank 80 were introduced into the gills 10 again with counter current.

The process diagram of the wastewater treatment facility shown in FIG. 6 is a structure for preventing the deterioration of treatment efficiency of the digester 70 due to a high ammonia concentration. By lowering the ammonia concentration, which is increased by thermal hydrolysis, through phosphorus crystallization, 70 of the first embodiment. The ammonia concentration in the thermal hydrolysis of the concentrated sludge in the sludge concentration tank 80 is increased to about 10 g / L. Such a high concentration of ammonia significantly lowers the disposal capacity of the digester 70. Therefore, it is often necessary to remove ammonia appropriately before entering the digester 70, so that the phosphorus crystallization reaction is introduced to the front of the digester 70 to recover ammonia together with the phosphate, thereby improving the efficiency of the digester 70 .

Fig. 7 is a modification of Fig. The configuration of Fig. 7 will be described only in the difference from the embodiment of Fig. 7, the raw sludge 21 is directly introduced into the digester 70 without passing through the sludge thickening tank 60. Therefore, the supernatant of the sludge concentration tank 61 having a low concentration of phosphate can be transported to the water treatment process without flowing into the crystallization facility, thereby greatly reducing the capacity of the crystallization facility.

Figs. 8 and 9 are process flow charts in which the phosphorus recovery apparatus of the present invention is applied to food waste disposal and livestock manure disposal. In FIGS. 8 and 9, the phosphorus recovery device is shown as a single process. However, it should be understood that various modifications as shown in FIG. 2 to FIG. 7 can be applied to modified food garbage processing and livestock powdering processing . The present invention, which crystallizes phosphate from reflux water containing high-concentration phosphorus generated in a wastewater treatment facility to recover useful phosphorus resources and improves the treatment capacity of the biological water treatment process, It is also applicable to livestock manure treatment facilities. This is because the treatment process of the food waste treatment facility and the livestock manure treatment facility is the same or very similar to the sludge treatment process of the wastewater treatment facility.

The treatment of food waste and livestock manure is divided into pretreatment, anaerobic digestion and biological water treatment. Food waste and livestock manure collected at the treatment facility are first subjected to a pretreatment process. In the pretreatment process, the food waste is made into a liquid slurry state by removing the foreign matter and making the particle size to a desired size, and the livestock manure is separated into the urine and the urine by the removal of the soil and the solid-liquid separation. The slurry and the supernatant generated in the pretreatment process are introduced into the anaerobic digestion tank 70 and treated. Most of the organic substances are oxidized and removed by the methane gas by the metal fermentation microorganisms. Finally, the anaerobic digestion liquid is separated into digestion sludge and digestion supernatant in the digestion and concentration tank (80). The dehydrated filtrate and digestion supernatant generated in the digestion process of digestion sludge are discharged after being treated through the biological water treatment facility. However, since the nitrogen and phosphorus in the anaerobic digestion process are almost not removed, the digestion supernatant contains high concentrations of nitrogen and phosphate, and the concentration of phosphate is usually 0.8 gP / L. Therefore, biologic water treatment facilities alone are difficult to satisfy the water quality standards of discharged water, so chemical treatment is often performed, but high operation cost is a problem. Therefore, it is also possible to provide an insoluble recovery device at the downstream end of the digestion concentrator (80) as in the sludge treatment process of the sewage and wastewater treatment facility, to recover a useful factor source from the digestion supernatant containing high concentration of phosphorus through the poorly soluble phosphate crystallization And the treatment efficiency can be improved by reducing the nitrogen and phosphorus load of the biological treatment facility.

Hereinafter, the phosphorus recovery apparatus for recovering phosphorus from the sludge obtained from the sludge thickening tank supernatant, the digestion concentrate supernatant, the dehydration filtrate or the hydrolysis apparatus will be described in more detail. 2 to 7, the phosphorus recovery apparatus includes a crystallization storage vessel 110, a crystallization reaction vessel 120, a pH control liquid injection unit 130, and a crystallization agent input unit 130.

As a method of recovering phosphorus from the reflux water, the MAP method and the HAP method which make and recover the poorly soluble phosphate are economical and efficient. MAP is known as struvite, and the crystal formula is MgNH ₄ PO ₄ 6 H ₂ O. Its physical properties are decomposed when heated to a specific gravity of 1.7 and has a low solubility in water but high solubility in acidic solutions and insoluble in alkaline solutions. MAP is composed of 1 mole of ammonia and 1 mole of phosphoric acid, and it is a method which can efficiently remove phosphate and ammonia nitrogen simultaneously. In the MAP method, magnesium ions are added to a treatment liquid containing phosphate and ammonia ions, and a hexagonal crystal is formed as shown in Formula 1 through the following crystallization reaction in a predetermined pH region.

MAP is known to be formed in the line of the anaerobic digestion tank of the existing sewage treatment plant because the anaerobic digestion liquid contains ammonia nitrogen and phosphate at a high concentration and maintains a proper pH for the crystallization. Therefore, MAP method is one of the most suitable crystallization methods to recover phosphorus and nitrogen at the same time in the case of the reflux water containing ammonia nitrogen and phosphate at high concentration.

On the other hand, HAP consists of 5 moles of calcium and 3 moles of phosphate, and its chemical formula is Ca ₅ (PO ₄ ) ₃ (OH). The crystal belongs to the hexagonal system and has hexagonal columnar shape and hexagonal shape. The physical property is 3.16, which is the main component of phosphorus. It is a mineral with high economic value. In the HAP method, calcium is added to a high-concentration phosphate-containing water, and HAP is produced through a crystallization reaction such as the formula (2) in a predetermined pH range.

Sludge generation is low, long-term stable efficiency can be obtained, and it is easy to introduce into existing treatment facilities because of its small area.

Fig. 10 is a device configuration diagram schematically showing the phosphorus recovery device of the present invention. The crystallization storage tank 110 is provided with a reflux water inlet valve 101 and is provided with an outlet valve 102 for discharging the reserved reflux water maintained at a proper pH for crystallization to the crystallization reaction tank 120, an agitator 103 for preventing pH adjustment and precipitation, a pH meter 104 for adjusting the pH of the influent recirculated water, and a water level gauge 105 for monitoring the water level of the crystallization storage tank 110 are provided.

The function of the crystallization storage tank 110 is to temporarily store a small amount of generated unreacted water generated in the sludge treatment process of the biological advanced treatment facility and to adjust the pH to be supplied from the pH adjusting solution input unit 130 for crystallization in the crystallization reaction tank 120 It is necessary to use the regulator to maintain the optimum pH range.

Further, the shape of the crystallization storage tank 110 is preferably rectangular and circular, and the capacity of the bath, that is, the residence time is suitably about 15 to 20 minutes, and it is possible to install the crystallization storage tank 110 with economical efficiency and small area.

The crystallization reaction tank 120 according to the preferred embodiment of FIG. 10 includes an inlet valve 201 into which the recycle water in the crystallization storage tank 110 maintaining the optimum pH for crystallization flows into the crystallization reaction tank 120, There is provided a reflux water outlet valve 202 in which the removed reflux water is returned to the water treatment process.

In the phosphate crystallization reaction tank 120, a stirrer 203 is provided for introducing the drug from the crystallization reaction chemical tank 140 and mixing the reflux water at a constant rate for crystallization using the introduced drug, (Not shown).

The crystallization reaction tank 120 further includes a water level meter 204 for monitoring the level of the internal reflux water and a time controller 205 for controlling the crystallization reaction time. The poorly soluble phosphate crystals 206 are formed by appropriate stirring in the reaction tank 120 of the phosphite crystallization reaction tank.

Since the phosphate 206 is formed and the specific gravity of the crystal 206 is 1.7 to 3.16, it is a main component of the phosphate. Therefore, the crystal 206 is a mineral having a high economic value and functions so as to be recovered and recycled. It is a technical feature.

The shape of the crystallization reaction tank 120 is preferably rectangular and circular, and is generally made of a concrete structure or a material which is not corroded by acid or alkali, and is made of a material having stabilized corrosion resistance and durability. The capacity of the reaction tank can be secured by securing a residence time of about 20 minutes of a small amount of recirculated water inflow, thereby ensuring economical efficiency in the installation of the reaction tank.

The drug supply facility according to the preferred embodiment of FIG. 10 includes a pH regulating solution inlet 130 for supplying a pH regulating solution for adjusting the optimum pH range to the crystallization storage bath 110, And a crystallization agent input portion 140 for supplying magnesium or calcium for phosphate crystallization.

The pH control liquid is supplied to the crystallization storage tank 110 and the phosphate crystallization tank 120 so that the pH control liquid can be supplied to the crystallization storage tank 110. When the crystallization storage tank 110 is not used . That is, in some cases, it is also possible to provide only the crystallization reaction tank 120 without installing the crystallization storage tank 110, and to allow the pH adjustment liquid to be supplied thereto.

It is preferable to provide an agitating facility in order to prevent the coagulation or sedimentation of the drug in the pH regulating liquid injecting unit 130 and the crystallization drug injecting unit 140 and it should be used as a material having excellent alkali resistance, corrosion resistance and durability against chemicals .

The chemical injection unit including the pH control liquid input unit 130 and the crystallization chemical input unit 140 must be easy to control the injection amount and be reliable and can also be freely adjusted in a suitable range. Facilities are needed.

FIG. 11 is a schematic view showing a configuration of a crystallization reaction tank 120 according to a preferred embodiment of the present invention and a device for withdrawing and recovering crystals by forming phosphate crystals 206 by stirring the reactants for crystallization into the sludge counter current water FIG. Fig. 11A is a plan view of the crystallization reaction tank, Fig. 11B is a sectional view of A-A 'in Fig. 11A, and Fig. 11C is a sectional view of B-B' in Fig. 11A.

The structure of the crystallization reaction tank 120 is configured such that the reaction water 213 flowing into the reflux water flowing from the crystallization storage tank 110 is rapidly dispersed with the weakly soluble phosphate of the reflux water to stir the mixture Two or more channel-shaped screw conveyor barrier walls 213 for smoothly drawing out the phosphate crystals 206, and a manhole for withdrawing the phosphate crystals 206 out and returning the countercurrent water.

The apparatus for extracting the phosphate crystals 206 includes a screw conveyor 207 having a power driving unit, an outflow water source 208 for withdrawing phosphate-free reflux water and the phosphate crystals 206, a phosphate crystals 206 A screen support 212 supporting the simple screen 209, a jib crane 211 for withdrawing the simple screen 209, a phosphite crystal 206 to the simplified screen 209 ) To form a crystal inducing device 210 for smoothly inducing the crystals.

A method of extracting and recovering phosphate crystals 206, that is, phosphates, is a method in which phosphate crystals 206 of a predetermined size are formed and precipitated by stirring in a phosphate crystallization reaction vessel 200, and then the outlet water gate 208 is opened and the screw conveyor 207 is operated The screw conveyor 207 guides the precipitated crystals, that is, phosphorus, in the direction of the outflow gate 208 and is resinized on a simple screen 209 for collecting crystals through a crystal guiding device 210, and the simple screen 209 is connected to a jib crane (211) to perform the phosphorus recovery.

The sludge counterflow water from which the poorly soluble phosphate is removed flows out to the outflow gate 208 together with the phosphate crystals 206 and is returned to the water treatment facility through the simple screen 209 and the counterflow water outflow tank.

While the preferred embodiments of the present invention have been described and illustrated above using specific terms, such terms are used only for the purpose of clarifying the invention, and it is to be understood that the embodiments of the invention and the described terminology are intended to cover various modifications, It is obvious that various changes and changes can be made without departing from the scope of the present invention. Such modified embodiments should not be understood individually from the spirit and scope of the present invention, but should be regarded as being within the scope of the claims of the present invention.

1: influent 10:
20: primary settling tank 21: raw sludge
30: Bioreactor 51: Surplus sludge
50: Secondary settling tank 60: Sludge thickener tank
61: Enrichment tank supernatant 65: Thermal hydrolysis apparatus
70: digester 80: digester thickener
81: Digestion concentrate supernatant 90: Dehydrator
91: dehydrated filtrate 100: effluent
110: crystallization storage tank 120: crystallization tank
130: pH adjusting liquid injecting part 140: Crystallizing agent injecting part
150:

Claims (11)

A first settling tank for settling inflow water flowing from the gilt-bed; a bioreactor for treating the inflow water introduced from the first settler using microorganisms; 1. A wastewater treatment facility comprising a secondary settling tank for settling influent water to be introduced therein,
A sludge concentration tank for concentrating excess sludge generated from the secondary settling basin,
A thermal hydrolysis device for hydrolyzing the sludge introduced from the sludge concentration tank,
A crystallization device for adding phosphorus to the sludge hydrolyzed in the hydrolysis device to adjust the pH of the sludge,
A digester for digesting inflow water that has passed through the phosphorus crystallization device,
A digestion concentrating tank for receiving digested sludge from the digestion tank and concentrating the digested sludge,
And a dehydrator for dehydrating the concentrated sludge in the digestion concentration tank,
And the desorption filtrate dehydrated in the dehydrator is introduced into the phosphorus crystallization apparatus.
The method according to claim 1,
Wherein the raw sludge produced from the primary settling tank flows into the digester.
A first settling tank for settling inflow water flowing from the gilt-bed; a bioreactor for treating the inflow water introduced from the first settler using microorganisms; 1. A wastewater treatment facility comprising a secondary settler that precipitates inflow water,
A sludge concentration tank for concentrating excess sludge generated from the secondary settling basin,
A digester for digesting the sludge passed through the sludge concentration tank,
A digestion concentrating tank for receiving digested sludge from the digestion tank and concentrating the digested sludge,
A phosphorus crystallization device that receives at least the supernatant from the digestion-concentrating tank and then adjusts the pH by inputting a pH control solution and inputs crystallization agent to produce phosphorus crystals;
And a dehydrator for dehydrating the concentrated sludge in the digestion concentration tank,
Characterized in that the desorption filtrate dehydrated in the dehydrator is introduced into the phosphorus crystallization apparatus,
The phosphorus crystallization apparatus
A crystallization storage tank for temporarily storing inflow water to be introduced,
a pH control liquid inlet for storing a pH control liquid and inputting a pH control liquid to the influent water flowing into the crystallization storage vessel;
A crystallization reaction tank which receives influent whose pH is controlled from the crystallization storage tank and then generates phosphate crystals from the influent;
And a crystallization agent input unit for storing a chemical for generating a phosphate crystal and inputting a crystallization agent into the crystallization reaction vessel.
The method of claim 3,
And the raw sludge produced from the primary settling tank flows into the digester.
The method of claim 3,
Wherein the raw sludge produced from the primary settling tank flows into the sludge concentration tank.
6. The method according to any one of claims 3 to 5,
Wherein a thermohydrolysis device is further provided between the sludge concentration tank and the digester, and the hydrolysis device transfers hydrolysis of the sludge introduced from the sludge concentration tank to the digester.
The method of claim 3,
And a supernatant of the sludge concentration tank is also introduced into the phosphorus crystallization apparatus.
A food garbage / livestock manure treatment facility comprising a pretreatment tank for removing foreign matter and gravel contained in incoming food waste or livestock manure,
A thermohydrolysis device for hydrolyzing the sludge obtained through the pretreatment tank,
A crystallization device for adding phosphorus to the sludge hydrolyzed in the hydrolysis device to adjust the pH of the sludge,
A digester for digesting inflow water that has passed through the phosphorus crystallization device,
A digestion concentrating tank for receiving digested sludge from the digestion tank and concentrating the digested sludge,
Further comprising a dehydrator for dehydrating the concentrated sludge in the digestion concentrator,
Characterized in that the desorption filtrate dehydrated in the dehydrator is introduced into the phosphorus crystallization apparatus,
The phosphorus crystallization apparatus
A crystallization storage tank for temporarily storing inflow water to be introduced,
a pH control liquid inlet for storing a pH control liquid and inputting a pH control liquid to the influent water flowing into the crystallization storage vessel;
A crystallization reaction tank which receives influent whose pH is controlled from the crystallization storage tank and then generates phosphate crystals from the influent;
And a crystallization agent input part for storing a chemical for producing phosphate crystals and injecting a crystallization agent into the crystallization reaction vessel.
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