KR20140131239A - Sewage and wastewater treatment system with crystallization apparatus for phosphorus recovery - Google Patents

Abstract

The present invention relates to a sewage and wastewater treatment facility. The sewage and wastewater treatment facility according to the present invention comprises: a sedimentation basin for removing sediment from introduced sewage or wastewater; a first settling basin for settling inflow water introduced from the sedimentation basin; a bioreactor for treating the inflow water introduced from the first settling basin using microorganisms; and a second settling basin for settling the inflow water introduced from the bioreactor. The sewage and wastewater treatment facility comprises: a phosphate discharge device for discharging phosphate from remaining sludge generated from the second settling basin; and a solid separation basin for solid-liquid separating the sludge, which has been introduced from the phosphate discharge device, into supernatant liquid and sludge.

Description

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

The present invention relates to a wastewater treatment facility having a phosphorus crystallization apparatus, and more particularly, to a wastewater treatment facility having a phosphorus crystallization apparatus, and more particularly, And a phosphorus and wastewater treatment facility having a phosphorus crystallization device for improving 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. At this time, phosphorus removal from the sewage is achieved by removing the microorganisms accumulating polyphosphate in the cell in the form of sludge in the final sedimentation tank of the biological advanced treatment process.

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. The concentrate supernatant (61), the digestion enhancer supernatant (81), and the dehydrated filtrate (91) can be reintroduced into the raw water.

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).

이다. 물리적 성질은 비중이 1.7로 열을 가하면 분해되고 물에 용해도가 낮지만 산성용액에서는 높은 용해성을 가지며 알칼리성 용액에서는 불용성이다. MAP는 암모니아 1몰과 인산 1몰로 구성되어 있어 인산염과 암모니아성 질소를 동시에 효율적으로 제거할 수 있는 방법이다. MAP법은 인산염과 암모니아 이온을 함유한 처리 대상액에 마그네슘 이온을 첨가하고 소정의 pH영역에서 다음과 같은 결정화 반응을 통해 6수염 결정을 화학식 1과 같이 생성한다.MAP is known as Struvite, and the formula of the crystal is

to be. 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 is composed of 5 moles of calcium and 3 moles of phosphate, and its chemical formula is Ca ₅ (PO ₄ ) ₃ (OH), and the crystal belongs to hexagonal system and is formed into hexagonal columnar shape and hexagonal plate shape. The physical property is 3.2, which is the main component of phosphorus, and 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.

However, in the anaerobic digestion process, all of the polyphosphoric acid contained in the cells is hydrolyzed and is difficult to elute into phosphate. Thus, in order to increase the resource recovery rate, a pretreatment process of excess sludge is required. Furthermore, in order to commercially use the poorly soluble phosphate crystals recovered from the reflux water, it is necessary to recover the crystals of high purity. However, since the anaerobic digestion liquid contains a high concentration of solid matter, it is difficult to recover highly pure and poorly soluble phosphate crystals.

On the other hand, in a small-scale sewage treatment facility, the sludge generated from primary and secondary settling basins is mixed with a polymer flocculant to be dehydrated and then incinerated. Thus, finite resources are not recovered and are disposed of by incineration. Is difficult to recover. Therefore, regardless of the scale of the biological advanced treatment facility or the operation of the anaerobic digester, there is an urgent need to develop a process capable of eluting phosphate from the sludge generated in the phosphorus removal process and leaching it into poorly soluble phosphate crystals.

Patent Document 1: Korean Patent Laid-Open Publication No. 10-2000-0001804 (published on Jan. 15, 2000)

An object of the present invention is to provide a sewage / wastewater treatment facility having a phosphorus-crystallizing apparatus for efficiently recovering phosphorus from reflux water containing high-concentration phosphorus by efficiently arranging apparatuses constituting a sewage / wastewater treatment facility.

An object of the present invention is to provide a wastewater treatment facility having a phosphorus crystallization apparatus for recovering phosphorus, which is a useful resource, by using an insoluble phosphate crystal phenomenon from reflux water containing high concentration of phosphorus generated in a biological advanced treatment facility.

Another object of the present invention is to provide a wastewater 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 introduced from the primary clarifier with microorganisms, And a second settling tank for settling the inflow water flowing in from the bioreactor, wherein the sludge concentration tank comprises a sludge concentration tank for concentrating excess sludge generated in the secondary settling tank and a sludge concentration tank for removing phosphate from the excess sludge generated in the sludge concentration tank, A first solids separation tank for separating the sludge obtained from the front stage into a supernatant liquid and an excess sludge and a supernatant liquid generated from the first solids separation tank, The phosphorus crystallization field, which controls the pH and introduces a crystallization agent to produce phosphorus crystals And by a waste water treatment, comprising a step of including the facilities can be achieved.

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 .

According to the present invention having the above-described characteristics, the recovery rate of the high-purity and poorly soluble phosphate crystals is increased from the high-purity water containing high-concentration phosphate which is generated in the secondary settling tank, anaerobic digestion tank and dehydrator of the biological advanced treatment facility and circulated through the water treatment process. It is possible to create added value higher than phosphorus crystallization facility.

1 is a process block diagram of a conventional wastewater treatment facility.
FIG. 2 is a partial process diagram of a wastewater treatment facility according to an embodiment of the present invention; FIG.
FIG. 3 is a partial process diagram of a wastewater treatment facility according to an embodiment of the present invention. FIG.
FIG. 4 is a partial process diagram of a wastewater treatment facility according to an embodiment of the present invention. FIG.
5 is a detailed block diagram of a phosphorus recovery system facility according to the present invention.
FIG. 6 is a device configuration diagram showing a MAP crystallization reaction tank according to one embodiment of the present invention in detail. FIG.
FIG. 7 is a schematic view showing an example of a HAP crystallization reaction tank according to the present invention. FIG.

The present invention relates to a method for recovering phosphorus from a waste water treatment plant by adding a phosphate release device and a solids separation tank to recover phosphorus containing phosphorus at a high concentration and recycling the phosphorus as a useful resource, , It is suggested to improve the phosphorus removal efficiency, reduce the operation maintenance cost, and improve the water quality of the discharged water by reducing the phosphorus load in the water treatment process.

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 containing the supernatant, the dotted line indicates the movement path of the sludge, and the dashed line indicates the phosphorus crystal.

Since the process up to the secondary settling tank 50 proceeds by the same process as the process block of the conventional lower wastewater treatment facility, the process for the previous step of the secondary settling tank 50 is omitted, The detailed description will be made from a later stage. That is, in the present invention, as shown in FIG. 1, the inflow water 1 of the influent wastewater and sewage is introduced into the chimney 10, firstly precipitated in the primary clarifier 20, The same procedure is repeated until the microorganism is used for treatment and then the microorganism is precipitated again in the secondary settler 50. Therefore, the following description will be made from the stage after the secondary settling tank 50. For reference, the sludge generated in the primary settling tank 10 is called raw sludge, and the sludge generated in the secondary settling tank 50 is called excess sludge.

2 is a partial process diagram of a wastewater treatment facility according to an embodiment of the present invention. As shown in FIG. 2, the sludge concentration tank 60 and the crystallization storage tank 110 concentrate the excess sludge generated in the secondary settler of the small scale advanced treatment facility where the digester is not installed. The device 210 and the solids separation tank 220 are installed. The sludge treated in the secondary settling tank 50 flows into the sludge concentration tank 60. The surplus sludge concentrated in the sludge concentration tank 60 flows into the phosphate release device 210 and is discharged into the solids separation tank 220 after the phosphate is discharged to be solid-liquid separated from the supernatant and sludge and the filtrate is returned to the crystallization storage tank 110 ≪ / RTI > After the pH is adjusted through the pH regulating solution input part 130 in the state of being stored in the crystallization storage tank 110 for a predetermined time, the pH-adjusted solution is inputted to the crystallization reaction tank 120, and then the crystallization drug input part 140 And the phosphorus is crystallized (150) by injecting the drug. As will be described later, the pH adjusting liquid does not necessarily need to be supplied to the crystallization storage tank 110, but may be supplied to the crystallization reaction tank 120. The filtrate containing the high concentration phosphate of the crystallization storage tank 110 is again removed by the poorly soluble phosphate crystals 150 in the crystallization reaction tank 120 and then the crystallization filtrate is introduced into the gypsum. In order to further reduce the phosphorus load of the biological advanced treatment facility, the crystallization filtrate can be discharged together with the treated water of the biological advanced treatment facility after completely removing the phosphorus using the polymer flocculant.

The sludge generated in the solids separating tank (220) is mixed with the polymer flocculant and is dehydrated in the dehydrator (90) and taken out to the sludge cake. Since the concentration of phosphate is not high along with the sludge thickening tank (60) supernatant, the desalination filtrate can be treated in the water treatment process by flowing into the sedimentation basin. However, in order to increase the recovery rate of the phosphate, it can be recovered by flowing into the solids separation tank 220.

In the ginseng salt discharger 210, a physicochemical method such as a thermal hydrolysis method, a heat treatment method, a micro treatment method, an ultrasonic treatment method and an alkali treatment method can be used as a pretreatment method for releasing phosphate from excess sludge. Biological sludge is a part of simple organic matter, but excess sludge is a microorganism produced in the biological advanced treatment process. Most of the phosphorus removed in the wastewater treatment process is accumulated in the form of polyphosphate in the cells of the accumulating microorganism. These microorganisms are protected by cell walls and form flocs, making it difficult to release polyphosphoric acid in phosphate form from cells unless undergoing proper hydrolysis, such as anaerobic digestion. Therefore, it is necessary to elute the polyphosphoric acid in the excess sludge in phosphate form in an appropriate manner so as to maximize the methane generation and phosphorus recovery in the advanced treatment facility where the phosphorus recovery is possible in the biological advanced treatment facility and the anaerobic digester is installed. Thermal hydrolysis decomposes polyphosphoric acid into phosphate form during hydrolysis of excess sludge under high temperature and high pressure conditions. The heat treatment does not destroy the cell walls of the microorganisms but elutes the polyphosphoric acid from the excess sludge in phosphate form. This method utilizes the physiological characteristics of the phosphorus-accumulating microorganisms that release intracellular phosphorus at high temperatures. The optimum temperature is around 70 ° C., where about 80% of the phosphorus present in the cells is released in phosphate form. Methane produced in the anaerobic digestion process can be used as a heat source for the heat treatment. This effect can also be obtained by microwave treatment. Microwave induces friction between molecules to generate heat. Since it is heated by the heat generated from the material itself, there is little energy loss, and the heating uniformity and heat efficiency are high in a very short time.

Furthermore, even with ultrasonic treatment, phosphate can be eluted from surplus sludge, which utilizes the cavitation phenomenon in which bubbles are generated by the negative pressure when ultrasonic waves pass through the medium. The bubbles generated by ultrasonic waves repeatedly expand and compress the adiabatic space, and local high-temperature and high-pressure gas is instantaneously released instantaneously. Heat effect and strong oxidizing substance such as OH radical are generated, and collision .

On the other hand, chemical treatment such as alkali treatment can release phosphate from surplus sludge, and caustic soda and lime can be used. This method has the advantage of saving alkali because the crystallization process of phosphorus is performed at a high pH condition. The physicochemical methods described above can be used in parallel with an oxidizing agent such as ozone to improve the efficiency.

3 is a partial process diagram of a wastewater treatment facility according to an embodiment of the present invention. 3 is a block diagram showing another embodiment of the present invention. In the advanced treatment facility provided with the digester 70, a phosphate release device 210 is provided between the excess sludge thickener 60 and the anaerobic digestion tank 70, And a solids separation tank 220 between the crystallization storage tank 110 and the phosphorus crystallization storage tank 110. The phosphate release device 210 maximizes the methane fermentation of the anaerobic digester 70 and minimizes the amount of sludge generated by releasing the polyphosphoric acid in the surplus sludge in phosphate form and hydrolyzing some excess sludge. Furthermore, it further enhances phosphate elution during the anaerobic digestion process to maximize phosphorus recovery through phosphate crystallization. In addition, the solids separating tank 220 separates the solids contained in the digestive juice, thereby producing a highly pure and poorly soluble phosphate crystal.

In order to realize this, the excess sludge concentrated in the sludge concentration tank (60) is introduced into the phosphate release device (210), treated and introduced into the anaerobic digestion tank (70) together with the raw sludge of the primary sedimentation tank. (80). ≪ / RTI > The concentrated digestion sludge is mixed with the polymer flocculant and is dehydrated in the dehydrator 90 and discharged to the sludge cake. The desulfurization filtrate can be introduced into the gypsum as described above to minimize the size of the phosphate crystallization reaction tank. However, 80 to the solids separating tank 220 to be subjected to solid-liquid separation, and then the filtrate can flow into the crystallization storage tank 110 to maximize the recovery of phosphorus. The filtrate containing the high concentration phosphate of the crystallization storage tank 110 is recovered as an insoluble phosphate crystal in the crystallization reaction tank 120 and then the crystallization filtrate is introduced into the gypsum.

4 is a partial process diagram of a wastewater treatment facility according to an embodiment of the present invention. FIG. 4 is a diagram showing the modified structure of FIG. 3, further comprising a first solids separation vessel 220a between the phosphate release apparatus 210 and the anaerobic digestion tank 70. The solid separation tank provided between the digestion-concentrating tank 80 and the crystallization storage tank 110 is referred to as a second solid-liquid separation tank 220b in order to distinguish it from the first solid-liquid separating tank 220a. The surplus sludge treated in the phosphate releasing device 210 flows into the first solids separation vessel 220a and the recovered supernatant is recovered into the crystallization tank 150 via the crystallization storage tank 110 and the crystallization tank 120. [ The concentrated sludge generated in the first solids separation tank 220a flows into the anaerobic digestion tank 70 and is digested and then flows into the second solids separation tank 220b so that the supernatant liquid is recovered to the phosphate crystallization storage tank 110. The sludge treated in the phosphate releasing device 210 may be separated from the first solids separation tank 220a into filtrate and sludge containing high concentration phosphate and the concentrated sludge may be introduced into the anaerobic digestion tank 70. [ Therefore, the residence time of the sludge in the anaerobic digestion tank 70 can be kept long, so that the anaerobic hydrolysis of the sludge can be promoted and the release of phosphate can be maximized.

5 is a detailed configuration diagram of a crystallization apparatus according to the present invention. The crystallization apparatus generally refers to the crystallization storage vessel 110, the pH control liquid injection unit 130, the crystallization agent input unit 140, the crystallization reaction vessel 120, and the crystal collection vessel 160. The phosphorus crystallization apparatus is fed with a phosphate fluid, which is separated from the solids separation tank 220 having a solids separation facility such as a membrane separation facility or a fine screen facility. The crystallization apparatus includes a crystallization storage vessel 110 for temporarily storing phosphate influent, a crystallization reaction vessel 120 for producing and crystallizing phosphorus using the influent water introduced from the crystallization storage vessel 110, A crystallization agent input section 140 such as calcium chloride or magnesium hydroxide as crystallization agent and a crystallization agent feed port 140 for extracting the phosphorus crystals generated in the crystallization reaction vessel 120 to separate phosphorus ).

The solids separating tank 220 is a facility for producing high-purity phosphate crystals, and is equipped with a facility for separating sludge and supernatant liquid such as a membrane separation facility or a fine screen facility. Specifically, the solids separation tank 220 may be implemented with a cyclone (automatic centrifuge), a microfiltration membrane device, a fibrous filter, a micro strainer, a sieve filter, or the like. Cyclone (automatic centrifuge) is a device for separating suspended matters by centrifugal force using points having different specific gravity depending on particle size and density, and the microfiltration membrane device is made of a material such as cellulose, vinyl chloride, or polycarbonate It is a device that can remove suspended solids, colloid, bacteria and the like because it has micropores with a diameter of 10 microns or less as a filtration membrane. The fibrous filter is passed through a fiber filter cloth made of nylon or polyester, The micro strainer is a device that removes solid matter by sieving operation. It uses a metal or synthetic fiber micro mesh of about 20 to 60 microns in mesh size to remove relatively large algae or floating matter And the like, and the sand filter is a device for removing sand particles It is a device that passes liquid through a filter medium with a filter filled in a container and removes fine suspended substances to perform solid-liquid separation. In order to minimize the impurities in the recovered product, maximize the phosphorus purity and maximize the efficiency, the solids separation tank 220 of the above-mentioned example is applied with screen equipment or filtration equipment, strainer, micro disk filter, It is preferable to include a facility capable of removing as much as possible.

The crystallization storage tank 110 is a facility for temporarily storing a small amount of filtrate generated in the sludge treatment process. The crystallization storage tank 110 includes a filtrate inlet valve, a pH adjustment liquid inlet 130 for pH adjustment, And a water level meter (LIT) equipped with a valve and capable of grasping the water level. The shape of the crystallization storage tank 110 is preferably a rectangular or circular shape with an agitator, and a residence time of 15 to 20 minutes is suitable.

In the embodiment of FIG. 5, although the pH adjusting liquid input unit 130 is shown to input the pH adjusting liquid into the crystallization reaction tank 120, the pH adjusting liquid does not necessarily need to be input into the crystallization reaction tank 120, It can be inserted. It goes without saying that the pH adjustment liquid can be introduced into both the crystallization reaction tank 120 and the crystallization storage tank 110.

The drug supply facility is provided with a pH adjusting liquid input part 130 for controlling the optimum pH range in the crystallization reaction tank and a crystallization drug input part 140 for supplying magnesium or calcium for the phosphate crystallization. The pH adjusting agent in the pH adjusting liquid inlet 130 is supplied to the crystallization storage tank and the crystallization tank so that the operation can be performed even when the crystallization storage tank is not used according to the site conditions. The pH control liquid input part 130 and the crystallization agent input part 140 are preferably equipped with a stirring device for preventing the coagulation or sedimentation of the medicine, and a material excellent in alkali resistance, corrosion resistance and durability is used for the medicine. The chemical injection unit composed of the pH control liquid input unit 130 and the crystallization chemical input unit 140 is provided with a chemical injection facility such as a chemical dosing pump that can easily adjust the injection amount and is freely adjustable in a suitable range, Equipped.

The crystallization reaction tank 120 is composed of a tank having a double or triple structure depending on the type of phosphate crystals of MAP and HAP, and will be described in detail with reference to FIGS. 6 and 7. FIG.

The crystal recovery vessel 160 is a facility for separating and recovering the phosphate crystals generated in the crystallization reaction tank 120. The crystals drawn by the pump are collected by a simple screen and the simple screen is finally taken out by a crane to be collected do. The phosphorus recovery tank is provided with a support for supporting the simple screen and a treatment water outflow tank for draining the treatment water dehydrated in the simple screen and the treated water is returned to the water treatment facility .

FIG. 6 is a device configuration diagram showing the MAP crystallization reaction tank of one embodiment according to the present invention in detail. In the drawing, LIT indicates a level sensor, B indicates a blower, P indicates a pump, and T indicates a temperature sensor, and the water level is indicated by reference numeral 141.

The crystallization reaction tank maintains the optimum pH and temperature for the crystallization of phosphate, and the accessory device includes an inlet valve in which the half-flow water in the phosphate crystallization tank flows into the crystallization reaction tank, and a counterflow water flow A valve is provided. In addition, an outflow portion for transferring the resulting phosphate crystals to the phosphorus recovery tank by precipitation is provided below. Further, for the crystallization, a stirrer is installed inside the crystallization reaction tank to stir and mix the filtrate at a constant rate for crystallization by using the chemical introduced from the crystallization reaction chemical tank and the introduced drug. Further, a water level meter capable of grasping the water level and a time adjuster for adjusting the crystallization reaction time are further provided.

The shape of the crystallization reaction tank, which is preferably a square and circular shape, is generally made of a material that does not corrode acid or alkali such as a concrete structure or a steel plate tank, and a material having stabilized corrosion resistance and durability is used. The capacity of the reaction tank can be obtained by securing a residence time of about 20 to 30 minutes, but it is preferable to provide a phosphorus crystallization reaction tank by securing a residence time of 1 to 2 hours in consideration of stability.

The structure of the crystallization reaction tank is composed of a tank having a triple structure. The first tank is a cylindrical or square tank having an upper portion and a lower portion which are provided on the innermost side and have a first partition wall 152 as a tank constituting the admixture portion 121. The second tank includes a reaction portion 123, And is a cylindrical or rectangular tank having upper and lower openings and having a second partition wall 154 as a tank. Finally, the third tank forms a separation part 125, and the upper and lower parts are opened to form the outer wall of the crystallization reaction tank. As shown in FIG. 6, the bottom surface of the triple structure tank is narrowed at a certain distance from the bottom of the first tank, the second tank and the third tank, and the width is narrowed toward the center. Thereby forming a sediment portion 129 that is formed so as to be opposed to each other.

The internal structure includes an admixture portion 121 capable of rapidly dispersing and rapidly mixing the inflow water and the chemicals forming the crystal, and a reaction portion 123 where phosphorus crystals are generated. The structure of the external portion is solid-liquid separation And an outflow weir 127 for discharging the treated water from which the phosphate has been removed. In addition, a lower portion of the reaction tank is provided with a crystallization settling portion 129 in which crystals precipitate so as to enable solid-liquid separation for smooth drawing out of the phosphate crystals.

The phosphorus water supplied from the lower central portion rises in the admixture portion 121 and flows into the reaction portion 123 formed on the right and left sides. 6, the first partition wall 152 formed between the mixing portion 121 and the reaction portion 123 should be formed lower than the water level 141 at the upper portion, It should be formed long so that it can not be refluxed. Most of the phosphorus crystals are generated in the reaction part 123. Phosphorus crystals remaining after not reacting are accumulated in the sediment part 129 while solid-liquid separation is performed in the separation part 125, And is discharged through the outflow ware 127. The second partition wall 154 provided between the reaction part 123 and the separation part 125 is provided at the upper part of the reaction part 123 so that the raw water mixed with the chemical in the reaction part 123 smoothly passes to the separation part 125. [ And the height of the lower portion should be lower than the height of the first partition 152. The height of the lower portion of the first partition wall 152 should be lower than the height of the first partition 152.

Since the specific gravity of the MAP is relatively low at about 1.7, it can leak out through the leaking ware 127 due to the floating of the precipitated insoluble phosphate crystals. In order to overcome this problem, the present invention is configured in such a manner that the reaction vessel is divided into the admixture section 121, the reaction section 123 and the separation section 125, but the separation section 125 is extended to the lower end of the reaction vessel to prevent floating of the crystal. In the lower part, the structure of the sedimentation part 129 is formed in a cone shape so that the precipitated crystals can be easily drawn out.

Phosphate crystallization reaction tank is equipped with a stirrer or a stirrer for stirring and mixing at a constant rate so that crystallization occurs by reacting with the influent and a chemical introduced into the chemical inflow part 140, And equipment for stirring.

FIG. 7 is a configuration diagram showing an example of a HAP crystallization reaction tank according to the present invention in detail. The crystals of HAP have a specific gravity of about 3.2 and are heavier than MAP, so that it is easy to precipitate the phosphate crystals and rarely leaks out to the outside as drainage ware 127 of the reaction tank. Therefore, the reaction tank of the HAP is composed of a tank with a simpler double structure. And an admixture 121 capable of rapidly reacting with the pH adjustment and crystallization chemicals, and the reaction part 123 is formed in the lower part. As shown in the figure, since the mixing unit 121 and the reaction unit 123 are provided in one tank, they may be referred to as a mixing reaction unit without particularly dividing the regions. Most of the phosphorus crystals are extracted in the reaction part 123 and the remaining phosphorus crystals are transferred to the separation part 125 and ascending to solid-liquid separation. A settling portion 129 where phosphorus crystals accumulate, and an outflow weir 127 of treated water generated and removed by the phosphate crystals. A stirrer (M), which is a stirring facility for generating crystals, and a pump (P) to draw phosphorus crystals are formed in the lower part of the reaction tank. And a facility for uniformly draining the removed treatment water.

When the phosphorous water flows into the central upper end portion of the inner tank, phosphorus crystals are extracted while descending through the admixture portion 121 and the reaction portion 123, and the phosphorus mixed with the drug, And is lifted up to the outside tank through the open bottom. In the separating part 125, the remaining phosphorus crystals solidify and fall to the sedimentation part 129, and the treated water generated and removed by the phosphate crystals flows out through the outflow ware 127.

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.

For example, although the present invention has been described with respect to the treatment of wastewater, it is needless to say that the present invention can be applied to food waste treatment and livestock manure treatment. 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 can be treated using a process similar to the process shown in FIG. 2 to FIG.

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: discharged water (treated water)
110: crystallization storage tank 120: crystallization tank
121: Admixture 123: Reaction part
125: Separator 127: Spill Wear
130: pH adjusting liquid injecting part 140: Crystallizing agent injecting part
150: Crystal crystals 160: Crystalline collecting tank
152: first barrier rib 154: second barrier rib
210: Phosphate release device 220: Solids separator
220a: first solids separation vessel 220b: second solids separation vessel

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 in the secondary settling tank,
A phosphate discharge device for discharging phosphate from the excess sludge generated in the sludge concentration tank,
A first solid-liquid separating tank for solid-liquid-separating the sludge obtained at the preceding stage into a supernatant and surplus sludge,
And a phosphorus crystallization device for receiving the supernatant generated in the first solids-separation tank, adding pH adjusting liquid to adjust the pH of the supernatant, and adding crystallization agent to produce phosphorus crystals.
The method according to claim 1,
Wherein the phosphate generating device is implemented in one of a thermal hydrolysis method, a heat treatment method, a micro treatment method, an ultrasonic treatment method, and an alkali treatment method.
3. The method according to claim 1 or 2,
Wherein the sludge generated in the phosphate generator is received in the first solids separation tank.
3. The method according to claim 1 or 2,
A digester for digesting sludge generated in the phosphate generator,
A digestion concentrating tank for receiving digested sludge from the digestion tank and concentrating the digested sludge,
Wherein the sludge generated in the digester is collected in the first solids separation tank.
The method of claim 3,
A digester capable of digesting excess sludge generated in the first solids separation vessel;
A digestion concentrating tank for receiving digested sludge from the digestion tank and concentrating the digested sludge,
Further comprising a second solid-liquid separating tank for separating the sludge generated in the digester and concentrating tank into a supernatant liquid and an excess sludge by solid-liquid separation.
6. The method according to any one of claims 1 to 5,
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 for producing phosphate crystals from the influent water flowing from the crystallization storage tank, and
And a crystallization agent input unit for storing a chemical for generating phosphate crystals and injecting a crystallization agent into the crystallization reaction vessel.
The method according to claim 6,
Wherein the crystallization reaction tank is provided in a triple-tank structure consisting of a first tank, a second tank and a third tank from the inside, and an upper end height of a partition wall separating the first tank and the second tank is formed to be lower than a water level, Wherein a top height of a partition wall separating the second tank from the third tank is formed to be higher than a water level, and a bottom surface of the first tank and the second tank is formed to be opened.
8. The method of claim 7,
Wherein the lower surface of the crystallization reaction tank is formed to have a narrower shape toward the middle portion.
9. The method of claim 8,
Wherein the inflow water received from a front stage flows upward from a lower portion of the first tank.
The method according to claim 6,
Wherein the crystallization reaction tank is provided with a double tank structure consisting of a first tank and a second tank from the inside, and an upper end height of a partition wall separating the first tank and the second tank is formed higher than a water level, Wherein a bottom surface of the tank is formed to be open.
11. The method of claim 10,
Wherein the inflow water received in the front stage flows in a downward direction from an upper portion of the first tank.

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