KR101300466B1 - Apparatus for wastewater treatment and method for phosphorus removal from wastewater - Google Patents

Abstract

The present invention relates to a sewage and wastewater treatment apparatus and a method for removing phosphorus using the same, and more particularly, a phosphorus contained in a high concentration in the return water generated in the sewage and wastewater treatment apparatus is reduced in advance through a flotation separator. Sewage and wastewater can be used as a pretreatment process of the wastewater treatment system and treated together with the influent to reduce the total phosphorus concentration of the effluent discharged from the sewage and wastewater treatment facilities below the environmental standard and to reduce the amount of flocculant used for phosphorus removal. It relates to a treatment apparatus and a method for removing phosphorus using the same. Here, "recycle water" or "reject water" refers to a circulating water containing a high concentration of contaminants such as concentrated filtrate, dewatered filtrate, backwashed water and contaminated water generated during the process of sewage and wastewater treatment apparatus.

Description

Sewage and Wastewater Treatment System and Phosphorus Removal Method Using It {APPARATUS FOR WASTEWATER TREATMENT AND METHOD FOR PHOSPHORUS REMOVAL FROM WASTEWATER}

The present invention relates to a sewage and wastewater treatment apparatus and a method for removing phosphorus using the same, and more specifically, a phosphorus contained in a high concentration in return water (Recycle water or Reject water) generated in the sewage wastewater treatment apparatus in advance through a flotation separator. By reducing the total phosphorus concentration of the effluent water discharged from the sewage treatment plant below the environmental standard and reducing the amount of flocculant used for phosphorus removal, it is input to the pretreatment process of the sewage treatment system and processed together with the influent. The present invention relates to a sewage and wastewater treatment apparatus which can be used, and a phosphorus removal method using the same.

Recently, the standard of total phosphorus concentration of effluent discharged from sewage and wastewater treatment system has been greatly strengthened. In particular, according to the effluent water quality standard that will change from 2012, the total phosphorus concentration of effluent should be lowered to 0.2mg / L although it varies depending on the region.

Normal natural waters generally contain a total phosphorus concentration of 0.02 to 0.1 mg / L. Therefore, the total phosphorus concentration of the effluent should be maintained below 0.2mg / L to improve the water quality of the stream inflow.

Phosphorus contained in sewage water mainly exists in the form of orthophosphate, polyphosphate and organophosphorus by synthetic detergents. These phosphorus enters the wastewater in the form of manure, food waste, detergents, pesticides and fertilizers. Phosphorus, unlike nitrogen, is characterized by circulating in an insoluble precipitate or soluble form without diffusion into the atmosphere. Therefore, the method of removing phosphorus in sewage water is to convert phosphorus into insoluble precipitate and separate it from the water system.

Methods for separating phosphorus from water systems include chemical, biological and physical methods. The biological method is to separate phosphorus by using the 'phosphorus overingestion phenomenon' of microorganisms that stimulate the microorganisms and consume more phosphorus than is required for normal cell growth. For example, in the A / O process, which is one of the methods for removing biological phosphorus, the sludge is returned from the aerobic stage to the anaerobic stage and mixed with the wastewater flowing into the anaerobic stage, and the phosphorus in the returned microorganism is eluted as soluble phosphate. After the wastewater containing soluble phosphate is transferred to the aerobic step to allow the microorganism to ingest the soluble phosphate in excess, the microorganisms which absorb the phosphorus excessively are separated into excess sludge in the sedimentation tank.

Such a biological removal method is a method used in a conventional sewage treatment plant composed of a primary sedimentation tank, a bioreactor, and a secondary sedimentation tank. However, biological methods alone have difficulty maintaining the total phosphorus concentration of the effluent below 0.2 mg / L.

Thus, recently, chemical removal methods are mixed. The chemical method is to separate phosphorus in the form of insoluble or low solubility salts by mixing flocculants in sewage water. Coagulants include aluminum sulfate, sodium aluminate, ferric chloride, ferric sulfate and lime. Coagulation aids are also used if necessary. The types and dosages of these flocculants and flocculants are selected in consideration of the concentration of influent phosphorus, suspended solids concentration (SS), alkalinity, sludge treatment facilities, and final disposal methods. For example, high influent flow rates and phosphorus concentrations increase the amount of flocculant used. In addition, when the concentration of suspended solids in the influent is too low, the amount of flocculent aid must be increased for smooth formation of flocs.

For example, Figure 6 is a schematic process diagram showing an example of the wastewater treatment apparatus according to the prior art proposed to lower the total phosphorus concentration of the effluent. As shown, the sewage water treatment apparatus 1 is largely a pretreatment tank 2, a primary sedimentation tank 3, a bioreactor 4, a secondary sedimentation tank 5, a filtration device 6, a disinfection device 7 ) And the like. Therefore, the inflow water (A) flowing from the outside is introduced into the pretreatment process (2), the organic matter, nutrients such as nitrogen or phosphorus is purified through biological, chemical and physical treatment. In particular, phosphorus in sewage is removed through biological removal. And the discharged water (B) purified to an appropriate level is discharged to the river and the like through the disinfection device (7).

On the other hand, in order to reduce the total phosphorus concentration of the effluent, a flocculant dosing facility (25) (45) for introducing a flocculant upstream of the primary sedimentation tank (3) or the secondary sedimentation tank (5), or the secondary precipitation process ( Downstream of 5), a flocculation settling device composed of flocculant input facility and settling tank is separately installed.

Then, the phosphorus contained in the sewage wastewater is separated from the primary sedimentation tank 3, the secondary sedimentation tank or the coagulation sedimentation device by the coagulant injected from the flocculant input facility. In other words, phosphorus contained in sewage is treated through biological and chemical removal.

Then, downstream of the secondary precipitation tank 5, a physical removal process for removing phosphorus using sand filtration, filtration membrane or reverse osmosis membrane may be further added. In particular, recently, a phosphorus removal filtration apparatus for adsorbing and removing phosphorus contained in raw water by coating iron oxide on the surface of a filtering medium (sand, ceramic, plastic, etc.) has been developed. The phosphorus removal filtration device is to adsorb the phosphorus contained in the raw water by using the iron oxide-coated media to clean the media to separate the contaminated water containing phosphorus and to circulate the media to be used repeatedly. As such, when the phosphorus removal filtration apparatus is installed at the rear of the conventional wastewater treatment apparatus, phosphorus contained in the wastewater may be treated through biological, chemical phosphorus, and physical removal to satisfy the standard of total phosphorus concentration of the effluent.

On the other hand, the sludge (S) generated in the primary sedimentation tank (3), secondary sedimentation tank (5), coagulation sedimentation apparatus of the sewage treatment apparatus according to the prior art dewatering cake through the sludge thickening tank 320 and the dehydration device (340) Separation (C), the concentrated filtrate generated in the sludge concentration tank 320, the dehydration filtrate generated in the dewatering device 340 is circulated back to the pretreatment tank (2) of the sewage treatment system (1) to be treated with the influent. Doing. In addition, the backwash water generated in the filtration device 6 is also circulated to the pretreatment tank 2 of the sewage treatment system 1 so as to be reprocessed together with the influent.

As such, the concentrated filtrate, the dewatered filtrate, and the backwash water generated in the process of the wastewater treatment apparatus 1 are returned to the pretreatment tank 2 of the wastewater treatment apparatus 1 and reprocessed together with the inflow water A. In addition, the water discharged from the wastewater treatment system 1 and returned to the wastewater treatment system 1 and continuously circulated is referred to as "reflux water".

That is, "recycle water" or "reject water" refers to circulating water containing a high concentration of contaminants such as concentrated filtrate, dewatered filtrate, backwashed water and contaminated water generated during the process of the sewage treatment system 1. Such return water is generated during the process of the sewage treatment system 1 and is introduced to the pretreatment tank 2 of the sewage treatment system 1 again, and the purification process is repeated with the influent.

However, these reflux waters contain excessive amounts of organic matter and nutrients such as nitrogen or phosphorus, which adds an additional load to the sewage treatment system, causing deterioration of effluent water and excessive discharge of total phosphorus. That is, the flow rate of the return water is very small compared to the amount of inflow water, but the load of organic matter, nitrogen and phosphorus is considerably high because of high pollution. In particular, when considering the operating time of the sludge thickening tank 320 and the dewatering device 340, the change in phosphorus load by the return water is more than 2-3 times larger. Therefore, the return water flows directly into the sewage treatment system, which may cause a serious problem on the performance degradation of the treatment facility by instantly increasing the load of organic matter and phosphorus.

In addition, since the high concentration of reflux water flows into the primary settling tank 3, the secondary settling tank 5, or the flocculating settling device, the coagulant injected from the primary settling tank 3, the secondary settling tank 5 or the flocculating settling device is administered. There is a problem that the amount is increased. That is, the conventional wastewater treatment apparatus 1 adds a chemical removal process to the existing biological treatment process, so that the amount of flocculant is increased to lower the total phosphorus concentration of the effluent to 0.2 mg / L. However, when the amount of flocculant used increases, not only the drug cost increases but also the amount of sludge generated increases the sludge treatment cost. In particular, the sludge generated through chemical removal is not suitable for the production of renewable energy, so the sludge treatment cost is seriously increased.

In the conventional phosphorus removal filtration apparatus, contaminated water containing insoluble phosphorus and a high concentration of iron salt is generated. If the polluted water is discharged as it is, there is a situation in which secondary pollution by iron salt is generated.

The present invention is to solve the problems of the sewage and wastewater treatment apparatus according to the prior art, the main object of the present invention is to contaminate high concentrations of contaminants such as concentrated filtrate, dewatered filtrate, backwash water, etc. generated during the process of the sewage treatment system. Pre-treatment through a separate flotation tank to reduce the amount of contaminants to be treated in the sewage treatment system before the containing "reflux water" into the pretreatment tank of the sewage treatment system reduces the amount of flocculant used and the total phosphorus concentration of the discharged effluent. It is to provide a sewage and wastewater treatment system and a phosphorus removal method using the same to ensure compliance with regulations.

The present invention also reduces the amount of flocculant used to reduce the amount of flocculant by preventing the secondary environmental pollution by iron salt by removing the phosphorus contained in the return water by using the iron salt contained in the contaminated water generated in the phosphorus removal filter device. It is to provide a sewage and wastewater treatment apparatus that can be used and a phosphorus removal method using the same.

In order to achieve the above object of the present invention, the sewage and wastewater treatment apparatus according to the present invention includes a pretreatment tank, a primary sedimentation tank, a bioreactor, a secondary sedimentation tank, a filtration device, and a disinfection device for treating sewage water. In the wastewater treatment apparatus, a flocculant input device is installed upstream of the primary sedimentation tank or the secondary sedimentation tank, and a flocculant is introduced into the sewage water flowing into the primary sedimentation tank or the secondary sedimentation tank, or the flocculation sedimentation device is downstream of the secondary sedimentation tank. By installing a flocculant into the treated water discharged from the secondary sedimentation tank to lower the total phosphorus concentration of the discharged water, the concentration generated in the sludge thickening tank for concentrating the sludge generated in the primary sedimentation tank, secondary sedimentation tank or flocculation settling device The coagulant mixing tank and the flotation tank separate the filtrate, the dehydration filtrate generated from the dehydration device for dewatering the sludge and the backwash water generated from the filtration device. After processing in the floatation apparatus comprising characterized in that the purification treatment through the respective steps of the wastewater treatment apparatus with the incoming water by conveying the treated twos pretreatment of wastewater treatment equipment.

In addition, the sewage treatment apparatus according to the present invention, the phosphorus removal filtration device is further installed downstream of the secondary sedimentation tank, the contaminated water generated in the phosphorus removal filtration device supplied to the flotation separator contained in the return water It is characterized by removing phosphorus.

According to the present invention, by reducing the load of the contaminants to be treated in the sewage and wastewater treatment apparatus by pre-treatment of the return water generated in the process of the sewage and wastewater treatment apparatus through the flotation tank to return to the sewage and wastewater treatment apparatus It improves silver, reduces the use of flocculants and reduces the amount of sludge produced, which not only reduces the cost of drugs and maintenance, but also makes it possible to smoothly comply with the total phosphorus concentration regulation of the effluent discharged to rivers.

In addition, the present invention has the effect of reducing the amount of sludge used to prevent the secondary environmental pollution by iron salt by recycling the iron salt generated in the phosphorus removal filtration device to remove the phosphorus of the reflux water.

1 is a schematic configuration diagram showing an example of a wastewater treatment apparatus according to the present invention,
2 is a schematic configuration diagram showing an example of a flocculation sedimentation apparatus according to the present invention;
3 is a schematic configuration diagram showing an example of the flotation apparatus according to the present invention;
4A and 4B are conceptual views for comparing the wastewater treatment apparatus according to the present invention with a conventional wastewater treatment apparatus;
5 is a schematic configuration diagram showing an example of a wastewater treatment apparatus according to the prior art.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the sewage, wastewater treatment apparatus and phosphorus removal method using the same according to the present invention.

First, as shown in Figure 1, the wastewater treatment apparatus 10 according to the present invention, the pretreatment tank 20, the primary sedimentation tank 30, the bioreaction tank 40, the secondary sedimentation tank 50, the filtration device ( 60), comprising a disinfection device (70). Therefore, the inflow water (A) introduced from the outside is purified biologically, chemically and physically through a pretreatment process, a primary precipitation process, a bioreaction process, a secondary precipitation process, a filtration process, and a disinfection process, and finally, a disinfection device (70). At the end of), the discharged water (B) is discharged to the stream.

In addition, the sewage treatment apparatus 10 according to the present invention, in order to lower the total phosphorus concentration of the discharged water B, a flocculant input device 25, 35 upstream of the primary sedimentation tank 30 or the secondary sedimentation tank 50. To install a flocculant into the sewage water flowing into the primary sedimentation tank 30 or the secondary sedimentation tank 50, or install a flocculation sedimentation device 80 downstream of the secondary sedimentation tank 50 to separate the secondary sedimentation tank. A flocculant is added to the treated water discharged at 50 to further remove phosphorus contained in the treated water. At this time, the flocculation sedimentation apparatus 80 is comprised from the flocculant input apparatus 85, the flocculation mixing tank 86, and the tertiary sedimentation tank 87 as shown in FIG.

Therefore, the phosphorus contained in the sewage water is formed by the flocculant introduced from the flocculant injector 25, 45, 85 and forms the insoluble polo, and the insoluble precipitate is the primary sedimentation tank 30, the secondary sedimentation tank 50, or the tertiary sedimentation tank. Solid-liquid separation is carried out at 80.

Subsequently, the sewage treatment apparatus 10 according to the present invention includes a sludge treatment apparatus for treating sludge S generated in the primary sedimentation tank 30, the secondary sedimentation tank 50, and the third sedimentation tank 80. It is further provided.

The sludge treatment apparatus 300 is composed of a sludge storage tank 310, a sludge concentration tank 320, a sludge digestion tank 330 and a dehydration device 340. Therefore, the concentrated filtrate generated from the sludge thickening tank 320 and the dewatered filtrate generated from the dewatering device 340 are introduced into the flotation separator 200. In addition, the backwash water generated in the filtration process 60 is introduced into the flotation separator 200 through the backwash water storage tank 360.

On the other hand, the wastewater treatment apparatus 10 according to the present invention, phosphorus removal filtration to adsorb the phosphorus contained in the wastewater by using iron oxide coated media downstream of the secondary sedimentation tank 50 or the flocculation sedimentation apparatus 80 The device 100 is further installed. In addition, the contaminated water generated in the phosphorus removing filtration device 100 is introduced into the flotation separator 200 through the contaminated water storage tank 350.

Thus, the wastewater treatment apparatus 10 according to the present invention further includes a flotation separator 200 for pretreatment of the return water R such as concentrated filtrate, dewatered filtrate, backwash water and contaminated water generated in each process. It is characterized by.

3 is a schematic diagram showing a preferred embodiment of the flotation separator 200 according to the present invention. As shown, the flotation separator 200 of the present invention is composed of a flocculant input device 210, a flocculation mixing tank 220 and a flotation separation tank 230.

Therefore, the return water (R) generated from the sludge concentration tank 320, the dewatering device 340, the filtration device 60, the phosphorus removal filtration device 100 is introduced into the cohesion mixing tank 220, the cohesion mixing tank 220 ) Forms a floc containing insoluble phosphorus by the flocculant injected from the flocculant injector 210. In addition, the floe formed with the return water flows into the floatation separation tank 230 and the floc included in the return water is floated to the surface by the micro air droplets supplied from the bottom of the floatation separation vessel 230.

To this end, the floating separation tank 230 is provided with a bubble generator 250 for supplying fine air bubbles or high-pressure air separately. Therefore, the flocks contained in the reflux water are floated to the water surface by the micro air bubbles, and the scum formed on the water surface is removed by the scum removal device 240. And the treated water (E) treated in the flotation separation tank 230 is supplied to the pretreatment tank 20 of the sewage treatment apparatus 10 again.

In this way, the present invention, pre-treatment of the return water (R) generated in the sewage treatment apparatus 10 in the flotation separator 200, and then supplies only the treated water (E) to the sewage treatment apparatus (10) inflow water ( In addition to A), the wastewater treatment system 10 can be purged to solve the problem of overloading the wastewater treatment system, to reduce the total phosphorus concentration of the effluent by reducing the pollution level of the wastewater, and to reduce the amount of coagulant and reduce the chemical cost. In addition, the sludge generation cost is reduced by reducing the amount of sludge generated.

4 is a schematic conceptual view for comparing the wastewater treatment apparatus 10 according to the present invention with the wastewater treatment apparatus 1 according to the prior art. First, as shown in Figure 4a, the wastewater treatment apparatus 1 according to the prior art, the influent (A) and the return water (R) flowing into the wastewater treatment apparatus 1 is a pretreatment tank of the wastewater treatment apparatus (1). It is a direct inflow structure. Therefore, the wastewater containing high concentration of phosphorus flows into the primary sedimentation tank, the secondary sedimentation tank, and the third sedimentation tank of the sewage water treatment apparatus 1, so that a large amount of flocculant is required for phosphorus removal. In addition, since the flow rate of the return water (R) changes rapidly depending on the operating time of the dehydrator, the sludge concentration tank, or the filtration device, it is difficult to control the dose of the flocculant, so that the total phosphorus concentration of the effluent (B) is lower than the environmental standard. Difficult to manage

On the other hand, as shown in Figure 4b, the sewage treatment apparatus 10 in the present invention, by treating the effluent (R) containing a high concentration of organic matter, nitrogen and phosphorus in advance in the flotation separator 200 of nitrogen and phosphorus Only the treated water (E) whose concentration falls below an appropriate level is introduced into the wastewater treatment apparatus (10). Therefore, since the concentration of phosphorus flowing into the primary sedimentation tank, the secondary sedimentation tank, and the third sedimentation tank of the sewage treatment system 10 is not only low, but the concentration is always kept constant, the amount of flocculant used can be reduced, and the total amount of effluent B Easy to manage concentration

As such, the wastewater treatment apparatus 10 according to the present invention may not be circulated to the wastewater treatment apparatus 10 by directly circulating the return water R containing a high concentration of contaminants, and then pre-treated in the flotation separator 200 in advance. By only returning the treated water E to the sewage treatment system 10, the load of the sewage treatment system is reduced, thereby reducing the amount of flocculant used and improving the quality of the discharged water.

On the other hand, according to the present invention, a certain amount of flocculant is also used in the flotation separator 200 for treating the return water (R). However, the generated flow rate of the return water (R) is very small amount of 1 ~ 5.5% compared to the inflow amount, and because the total phosphorus concentration of the treated water (E) is high, even a small amount of flocculant can obtain high treatment efficiency. On the other hand, in the case of treating phosphorus introduced into the sewage treatment system through the return water according to the prior art, since the flow rate of the sewage water is 17 times more than that of the return water (R) and the total phosphorus concentration of the effluent (B) is low, Processing efficiency is low. Therefore, the wastewater treatment apparatus 10 of the present invention can reduce the amount of flocculant used in comparison with the conventional wastewater treatment apparatus 1 as a whole. In addition, when the amount of flocculant used is reduced, the amount of sludge generated is reduced, thereby reducing the sludge treatment cost.

 On the other hand, the sewage treatment apparatus 10 according to the present invention, by mixing the iron salt contained in the contaminated water generated in the phosphorus removal filtration device 100 used to lower the total phosphorus concentration of the effluent water into the countercurrent water (R) by mixing It can be recycled to remove phosphorus. That is, the contaminated water generated from the phosphorus removing filtration apparatus 100 contains a large amount of iron salts, which have the property of adsorbing phosphorus to form a precipitate. Therefore, when the mixed water (R) and the contaminated water containing iron salts are properly mixed, phosphorus removal efficiency can be further increased while reducing the amount of flocculant used.

Figure 5 shows an example of the phosphorus removal filtration device applied to the wastewater treatment apparatus of the present invention. The phosphorus removal filtration device 100 may be installed downstream of the filtration device 60 or may be installed in place of the filtration device 60. As shown, the phosphorus removal filtration device 100 is a sand filtration layer 110 is formed therein, the raw water passing through the sand filtration layer 110 is moved upwards to remove contaminants after the treated water The treatment water pipe 132 is formed on the upper portion so that the water flows out from the wear 130, and the raw water introduced into the filter pipe 108 through the inlet pipe 106 is injected into the sand filtration layer 110. Dispersion pipe 112 to be installed, and the air lift pipe 114 is installed perpendicular to the filter barrel 108 and to inject air supplied from an air compressor (not shown) to raise the contaminated sand, and air It is installed at the upper end of the lift pipe 114 and the contaminated water chamber 164 to collect the first washed sand and contaminated water through the air leaf pipe 114, and to discharge the contaminated water collected in the contaminated water chamber 164 Is connected to the contaminated water chamber 164 and the other end is a contaminated water pipe 124 connected to the outside. , Is located below the contaminated water chamber 164, while falling downward to the washed sand primary consists of a sand cleaning section 104 is formed in a zigzag flow path 158 that to clean the secondary.

The phosphorus removal filtration device is installed in the sand filtration layer 110, the raw water supplied through the inlet pipe 106 is uniformly distributed throughout the sand filtration layer 110 by the dispersion pipe 112, the rise The pollutant (SS) is collected by the sand filtration layer 110, the treated water is moved to the upper portion and overflowed from the treated water wear 130 is discharged to the outside through the treated water pipe (132). The contaminated sand, which filters the raw water and captures the contaminants, is raised upward through the air lift pipe 114 by compressed air injected from the lower part of the air lift pipe 114, and at this time, the air lift pipe 114 The contaminant is separated from the contaminated sand as the contaminated sand, water and air rise at different rates. The sand collected in the contaminated water chamber 164 again falls downward through the zigzag flow path 158 of the sand washing unit 105 to be stacked on the sand filtration layer 110, and the contaminated water chamber 105 ) Contaminated water introduced into the sand is discharged to the outside through the contaminated water pipe (132).

At this time, the zig-zag flow path 158 formed in the sand washing unit 104 is connected to the top and the bottom so that the sand falling from the contaminated water chamber 164 moves to the bottom, and the treated water rising from the bottom moves to the top. The pollutant separated from the zigzag flow path 158 is moved to the polluted water chamber 164. However, as the amount of the treated water flowing into the contaminated water chamber 164 through the zigzag flow path 158 increases, the concentration of the contaminated water discharged through the contaminated water pipe 132 decreases, thereby lowering the filtration efficiency. In addition, when the treated water flowing into the polluted water chamber 164 is excessive, the flow rate of sand falling down through the zigzag flow path 158 is reduced, thereby reducing the cleaning efficiency of the pollutant. Accordingly, in the related art, the amount of the treated water flowing into the zigzag flow path 158 is adjusted by adjusting the difference between the contaminated water level in the contaminated water chamber 164 and the level of the treated water in the filter barrel 108.

As such, if the phosphorus removal filtration device 100 is further installed at the rear end of the wastewater treatment apparatus, phosphorus contained in the wastewater may be treated through biological, chemical and physical removal processes to satisfy the standard of total phosphorus concentration of the effluent.

Accordingly, various embodiments for checking the operation of the wastewater treatment apparatus according to the present invention will be described.

Comparative Example 1

Composition of Sewage Treatment System

The wastewater treatment apparatus to be compared includes a pretreatment tank 20, a primary settling tank 30, a biological reaction tank 40, a secondary settling tank 50, a flocculation settling device 80, a filtration device 60, and a disinfection device 70. It is configured to include. And the sludge generated in the first settling tank (30) and the second settling tank and flocculation settling device is treated through the sludge thickening tank, dehydration device, and the concentrated filtrate, dehydration filtrate and backwash water are returned directly to the pretreatment tank and circulated.

At this time, the influent flowing into the sewage treatment system was as shown in Table 1, the concentration of COD, T-N, T-P was 130 mg / L, 42 mg / L, 5.7 mg / L. The flocculant used in the flocculation flocculator 80 was 52 mg / L of PAC (17%), the coagulant was 1 mg / L of the polymer flocculant (0.2%), and the total phosphorus concentration of the effluent was 0.3 mg / L.

 Comparative wastewater treatment system test results Item Influent Effluent COD _Mn (mg / L)
TN (mg / L)
TP (mg / L) 130
42
5.7 20
15
0.3 Coagulant PAC (17%) 52 mg / L, 5,690 / tonne Flocculent aid Polymer coagulant (0.2%) 1 mg / L, 1,860 won / ton

Experimental Example 1

Configuration of sewage treatment apparatus of the present invention

The sewage treatment apparatus of the present invention includes a pretreatment tank 20, a primary settling tank 30, a bioreactor 40, a secondary settling tank 50, a phosphorus removal filtration device 100, and a disinfection device 70. It is composed. And the sludge generated in the first settling tank 30, the second settling tank and the flocculation settling device was processed through the sludge thickening tank, dehydration device and the concentrated filtrate and the dewatered filtrate were supplied to the flotation separator 200 for treatment.

At this time, the influent flowing into the sewage treatment system is COD, TN, TP concentration is 110 mg / L _, 38 mg / L, 3.9 mg / L, respectively, as shown in Table 2, the organic matter, nitrogen, load load 15%, 10% and 30% reductions were shown. As shown in Table 3, the amount of flocculant used was also pretreated by floating separation of the return water compared to the simple flocculation sedimentation method.

 Experiment result of the present invention device Item Influent Effluent COD _Mn (mg / L) 110 10 T-N (mg / L) 38 10 T-P (mg / L) 3.9 0.14 Coagulant Iron salt (40% liquid) 72.5 mg / L, 2,690 won / ton Flocculent aid -

Comparison of the operability between the device to be compared with the device of the present invention division Configuration Processing performance Drug usage
(mol / p-mol) Sludge
Increase / decrease compare
Target device Coagulation precipitation
(Alum) 80% 5.5 2.5 Coagulation precipitation
(PAC) 85% 4.5 1.5 germinal
Invention device Counterflow Water Treatment
And phosphorus removal filtration device 90%    2    One

[Experimental Example 2]

Treatment Effect in Flotation Separator

As shown in <Table 4>, the return waters with COD _Mn , TN and TP concentrations of 85 ~ 290 mg / L, 46 ~ 170 mg / L, and 18 ~ 110 mg / L, respectively, were tested in Al ₂ (SO ₄ ). ₃ (7% liquid) 1 ~ 4 L / m ³ Ca (OH) ₂ (20% liquid) 0.5 ~ 1.5 L / m ³ Polymer coagulant (0.2% liquid) 1 ~ 4 L / m ³ The COD _Mn , TN, and TP removal efficiencies were 52 ~ 86%, 43 ~ 52%, 91 ~ 97%, respectively. Based on these results, the pretreatment effect of the effluent may not only reduce the influent load rate of the TP by more than about 30%, but also be very effective in maintaining the TP water quality of 0.2 mg / L or less.

Result of Flotation Separation by Source of Wake Water Item Concentrated filtrate Tally Filtrate Backwash water Influent Treated water Influent Treated water Influent Treated water COD _Mn density
(mg / L) 162 71 290 139 85 12 Removal efficiency (%) - 56 - 52 - 86 T-N density
(mg / L) 92 52 170 93 46 22 Removal efficiency (%) - 43 - 45 - 52 T-P density
(mg / L) 60

4.2

110

5.1

18

1.5

Removal efficiency (%) - 93 - 97 - 91

[Experimental Example 3]

Performance and Recycling Effect of Phosphorus Removal Filter

Inlet flow rate is 55m ³ / day of sewage water flows in the secondary treatment plants to be treated the _{BOD 4.0 mg / L, COD Mn} 7.4 mg / L, SS 3.6 mg / L TP 1.5 mg / L, PO 4 -P 0.687 mg / L An advanced treatment experiment was performed using an phosphorus removal filter (IPR ^™ -Process). Results of operation after injecting iron salt coating 72.5 g / m ³ (40% liquid) under the experimental conditions of 9 m / hr of filtration line velocity of cylindrical phosphorus removal filtration device with diameter (F) of 0.6 m and height of 1.5 m Are shown in Table 5. As shown in Table 3, BOD, COD and SS removal efficiencies were 42.3%, 56,6% and 66,5%, respectively, and TP and PO ₄ -P were 89.5% and 96.5%, respectively. High removal efficiency was shown.

Phosphorus Removal Filter Operation Results Item Influent Runoff BOD density
(mg / L) 4.0 2.3 Removal efficiency
(%) - 42.3 COD _Mn density
(mg / L) 7.4 3.1 Removal efficiency
(%) - 56.6 SS density
(mg / L) 3.6 1.1 Removal efficiency
(%) - 66.5 T-P density
(mg / L) 1.5 0.14 Removal efficiency
(%) - 89.5 PO4-P density
(mg / L) 0.687 0.015 Removal efficiency
(%) - 96.9

Table 6 shows the results of the comparison with the iron salt coagulant (38% liquid) to recycle the iron salt from the phosphorus removal filter. As shown in Table 6, the removal efficiency of COD _Mn , TN, and TP is compared, which is slightly lower than that of iron salt coagulant. However, it could be recycled as a flocculant by mixing with the countercurrent.

Therefore, according to the present invention, if the treated water is pretreated in the flotation separator, the treated water is circulated to the sewage treatment system, thereby saving about 30% of the amount of flocculant. In addition, when the iron salt generated in the phosphorus removal filtration device according to the present invention is mixed with the return water flowing into the flotation separator, the amount of flocculant used could be reduced by about 10%.

Iron salt recycling test results       Item Phosphorus Removal Filter Iron Salt
recycle    Iron salt coagulant FeCl ₃ 0.100mL / L
+ Polymer 1 mg / L FeCl ₃ 0.125mL / L
+ Polymer 1mL / L COD Influent
(mg / L)
Treated water
(mg / L)
Removal efficiency
(%) 105

53.5

49 105

44.1

58 T-N Influent
(mg / L)
Treated water
(mg / L)
Removal efficiency
(%) 45

22

51 45

21.6

56 T-P Influent
(mg / L)
Treated water
(mg / L)
Removal efficiency
(%) 15

2.3

85 15

1.0

93

As described above, the sewage water treatment apparatus according to the present invention and the phosphorus removal method using the same, pre-treatment of the return water, such as concentrated filtrate, desorption filtrate, backwash water, etc. generated in the sewage water treatment apparatus through the flotation separator to the effluent water The concentration of phosphorus contained is lowered to a certain level, and only the treated water is supplied to the wastewater treatment plant and retreated with the influent to reduce the amount of flocculant used and to maintain the total phosphorus concentration in the effluent.

In addition, the present invention is to remove the phosphorus contained in the reflux water by introducing a contaminated water containing a high concentration of iron salt generated in the phosphate removal filtration device to the reflux water introduced into the flotation separator.

As described above with reference to the accompanying drawings for the preferred embodiment of the present invention, the present invention is not limited by the above-described specific embodiments, those of ordinary skill in the art Of course, various forms of modifications and variations are possible within the scope of the technical spirit of the present invention and the claims described below.

10: wastewater treatment device 20: pretreatment tank
25, 35, 85: flocculant input device 30: primary sedimentation tank
40: bioreactor 50: secondary precipitation tank
60: filtration device 70: disinfection device
80: flocculation settling device 86: flocculation mixing tank
87: 3rd settling tank 100: phosphorus removal filter
200: flotation device 210: flocculant input device
220: cohesion mixing tank 230: flotation separation tank
250: bubble generator 300: sludge treatment apparatus
310: sludge storage tank 320: sludge thickening tank
330: sludge digester 340: dewatering device
350: contaminated water storage tank 360: backwash water storage tank
A: Influent B: Effluent
C: Dehydrated Cake E: Treated Water
R: Regurgitation S: Sludge

Claims (8)

In the sewage and wastewater treatment apparatus including a pretreatment tank, a primary sedimentation tank, a bioreactor, a secondary sedimentation tank, a filtration device, a phosphorus removal filtration device and a disinfection device for treating sewage and wastewater,
The concentrated filtrate generated in the sludge thickening tank for condensing sludge generated in the primary sedimentation tank, the secondary sedimentation tank or the coagulation sedimentation apparatus, the dehydration filtrate generated in the dehydrating apparatus for dewatering the sludge, and the backwash water generated in the filtration apparatus. The iron salt generated from the phosphorus removal filtration device is added to the same reflux water, and is treated in a flotation separator consisting of a flocculant mixing tank and a flotation separation tank, and then the treated water can be returned to the pretreatment tank of the wastewater treatment device. Sewage and wastewater treatment equipment. The method of claim 1,
Sewage and wastewater treatment apparatus characterized by lowering the total phosphorus concentration of the effluent by installing a flocculant injector upstream of the primary sedimentation tank or the secondary sedimentation tank to put the flocculant into the sewage and wastewater flowing into the primary sedimentation tank or the secondary sedimentation tank. . The method of claim 1,
A sewage and wastewater treatment apparatus, characterized in that a flocculating settling device is installed downstream of the secondary settling tank to reduce the total phosphorus concentration of the effluent by injecting a flocculant into the treated water discharged from the second settling tank. delete delete delete The concentration of organic matter, nitrogen, and phosphorus in the condensate such as concentrated filtrate, desorption filtrate, and backwashing water from sewage and wastewater is reduced to a certain level, and then returned to the pretreatment tank of the sewage and wastewater treatment system to purify with influent. In the method of removing phosphorus contained in sewage and wastewater which can reduce the amount of coagulant consumed excessively and remove the inflow load, and can stably manage the total phosphorus concentration of the effluent.
A method for removing phosphorus contained in sewage / wastewater, wherein the iron salt generated from the phosphorus removal filtration device is added to the reflux water to remove phosphorus contained in the reflux water. 8. The method of claim 7,
The reflux water is a phosphorus removal method contained in the sewage and waste water, characterized in that the solid-liquid separation of the insoluble phosphorus combined with the flocculant using the flotation separator.

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