KR100271942B1 - Method for treating high density waste water and apparatus therefore using soil microbe with do controlling aeration tank - Google Patents

Abstract

The present invention relates to a method and apparatus for treating high concentration livestock wastewater including hardly degradable organic matter. Wastewater treatment method is to store the effluent separated from the wastewater in the storage tank to equalize the concentration and flow rate, and the effluent equalized from the storage tank in the anaerobic fermentation tank by anaerobic microorganisms for easy intake of subsequent microorganisms Hydrolyzing and activating the dephosphorizing microorganisms, activating the aerobic microorganisms to selectively improve the microorganisms in the sludge returned from the aeration tank in the microbial activator tank, increase biosorbability and grow microorganisms filled in the soil microbial carrier, and Mixing the effluent of the microorganism activator containing the soil microorganisms and the anaerobic fermenter effluent and the return sludge and the desorption liquid in a mixing tank, and treating the mixed solution in a dissolved oxygen concentration controlled aeration tank to treat organic matter and phosphorus and to treat ammonia nitrogen. Nitric acid Denitrifying the nitrate using endogenous breathing of microorganisms in anoxic state, and treating the treated liquid in the aeration tank, separating the denitrified liquid into sludge and supernatant in the first settling tank, and settling in the first settling tank. From the separated supernatant, residual phosphorus and suspended solids are removed from the coagulation sedimentation tank and the treated water is discharged.

Description

Method and device for high load purification of high concentration wastewater by using dissolved oxygen concentration aeration tank using soil microorganism

The present invention relates to a wastewater treatment method and apparatus for efficiently purifying livestock wastewater or organic industrial wastewater containing high concentration organic matter and nitrogen and phosphorus using soil microorganisms.

Livestock wastewater or organic industrial wastewater, which is recognized as the main cause of environmental pollution, such as causing eutrophication in the surrounding water system, is treated by a joint treatment plant or individual purification facilities depending on the size of the industry. However, in the case of livestock wastewater joint treatment plants, almost all of them are not functioning due to inadequate design load, and even in the case of individual septic tanks, due to the lack of adaptability to the wastewater concentration according to the type and the breeder of the livestock. The situation is not exhibited. In addition, it is difficult to secure industrial competitiveness because the cost invested to treat livestock wastewater or organic industrial wastewater is excessive compared to related industrial scale.

On the other hand, in the case of foreign countries, various methods such as anaerobic digestion, activated sludge method and oxidized paper have been applied in connection with the treatment of high concentration slurry phase wastewater such as livestock wastewater. See, eg, Jose R. Bicudo and Ivo F. Svoboda, “Intermittent aeration of pig slurry-farm scale experiments for carbon and nitrogen removal”, Wat. Sci. & Tech. Vol. 32, no. 12, pp 83-90, 1995, reported the results of treatment of pig wastewater in a dilute intermittent aeration method. However, in this purification treatment, the nitrification inhibition phenomenon occurs when the F / Mv ratio (substrate loading per unit time per unit microorganism mass in the reactor) is 0.8 kg BOD / kg Mv / d or more.

Meanwhile, Cintoli C., Di Sabantino, B., Galeotti, L. and Bruno, G., “Ammonia uptake and treatment in UASB reactor of piggery wastewater”, Wat Sci. & Tech. Vol. 32, no. 12, PP 76-83, 1995], the centrifugation of pig wastewater and the removal of NH ₄ ⁺ by the ion exchange method using a zeolite, the upflow Anaerobic Sludge Blanket (UASB) method and the UASB-anaerobic filter In a manner that removes COD, TN and TP to levels of 95%, 90% and 80%, respectively. Bortone G., Gemeli, S. and Rambaldi, A., “Nitrification, denitrification and biological phosphate removal in SBR treating piggery wastewater ”, Wat. Sci. & Tech. Vol 25, no. 5, pp 977-985, 1992] reported the removal of COD, TN and TP to 93%, 93% and 95%, respectively, by centrifugation of pig wastewater in a batch reactor. Yang, PY, Chen, H. Kongsrichareon, N. and Polprasert, C., “A swine waster package biotreatment Plant for the tropics”, Wat. Sci. & Tech. Vol. 28, No. 2, pp 211-218, 1993] report the results of simple anaerobic treatment of high concentration wastewater in small pigs. Martin, JH and Loehr, RC, “Aerobic treatment of poultry wastes”, J. Agri. Eng. Res. Vol. 21, pp 157-167, 1976, reported the results of treating poultry wastewater with the oxidative sphere method.

However, these foreign wastewater treatment examples are mostly for dilution-controlled wastewater except anaerobic digestion, which is quite different from domestic livestock wastewater conditions and requires much improvement in application.

In addition, although domestic livestock wastewater or manure is recognized as a major cause of aquatic eutrophication, existing treatment facilities focused on organic matter removal cannot solve environmental pollution problems such as eutrophication. Instead of existing facilities, technologies such as B ₃ or bio-reactor using microbial activators are being introduced to improve livestock wastewater treatment efficiency, but the operating costs of treatment facilities related to the supply of microbial agents are inefficient. There are many problems with the application of reality.

Accordingly, it is an object of the present invention to provide a wastewater treatment method and apparatus capable of efficiently treating high concentration wastewater.

In addition, another object of the present invention is to provide a wastewater treatment method and apparatus that can economically and efficiently treat livestock wastewater and organic industrial wastewater using soil microorganisms.

It is still another object of the present invention to improve the adaptability of the apparatus to rapid changes in wastewater concentration by using solidified soil microorganisms, and to treat wastewater for effectively treating organic matter as well as nutrients such as nitrogen and phosphorus at low cost, and To provide a device.

Another object of the present invention is applicable to small-scale wastewater generation facilities, efficient and economical wastewater treatment method and apparatus that can reduce the collection cost for co-treatment of livestock wastewater and solve the non-point pollution problem generated during the collection process To provide.

1 is a block diagram of a wastewater treatment process according to the present invention.

2 is a schematic view of an anaerobic fermenter used in the wastewater treatment apparatus of the present invention.

3 is a schematic diagram of a microorganism activator used in the wastewater treatment apparatus of the present invention.

4 is a schematic diagram of an aeration tank used in the wastewater treatment apparatus of the present invention.

5 is a schematic diagram of a denitrification tank used in the denitrification treatment of the present invention.

6 is a schematic diagram of a multiple gradient settling tank used in the wastewater treatment apparatus of the present invention.

7 is an internal structure diagram of a flocculation sedimentation tank used in the wastewater treatment apparatus of the present invention.

* Explanation of symbols for main parts of the drawings

10: wastewater treatment device 20: storage tank

30: anaerobic fermentation tank 40: microorganism active tank

42 soil microorganism carrier (bio clad) 44: internal activation tank

50: mixing tank 60: aeration tank

66: membrane 70: denitrification tank

75: contact medium 80: multiple inclined sedimentation tank

84: multiple gradient settling plate 90: flocculation settling tank

100: dehydrator

Waste water treatment method of the present invention for achieving the above object is the step of equalizing the concentration and flow rate by storing the effluent separated from the waste water in the storage tank, the effluent equalized from the storage tank by the anaerobic microorganisms in the anaerobic fermenter Hydrolyzing and activating dephosphorus microorganisms in an easy state for subsequent ingestion of microorganisms, selectively improving microorganisms in sludge returned from aeration tanks in a microbial activator, increasing bioadsorption capacity and growing microorganisms filled in soil microbial carriers The step of activating the aerobic microorganisms, mixing the effluent of the microorganism activator containing the solidified soil microorganisms with the anaerobic fermenter effluent, the return sludge and the desorption liquid in a mixing tank, and treating the mixed solution in a dissolved oxygen concentration controlled aeration tank. Organic matter And nitrifying the ammonia nitrogen, denitrifying the nitric oxide using the endogenous respiration of the microorganism in an aerobic state, and separating the denitrified liquid into the sludge and the supernatant in the primary sedimentation tank. And removing residual phosphorus and suspended solids in the coagulation sedimentation tank from the supernatant precipitated and separated in the primary sedimentation tank and releasing the treated water.

In addition, the wastewater treatment apparatus according to the present invention includes a storage tank for storing the discharged water separated from the wastewater to equalize concentration and flow rate, an anaerobic fermentation tank located downstream of the storage tank and performing anaerobic decomposition, and a soil microbial carrier is accommodated. A microbial activator having an internal activator and an diffuser, and an inlet through which the effluent and the return sludge flow into each of the microbial activator and the anaerobic fermentation tank, and a mixing tank configured to receive and mix inflows through the inlets; Dissolved oxygen concentration-controlled aeration tank connected to the downstream side of the mixing tank, a denitrification tank having an inlet and outlet and an inner contact medium into which the aeration tank treatment liquid connected to the downstream side of the aeration tank flows, and a supernatant connected to the downstream side of the denitrification tank The inlet and outlet and the primary sedimentation tank and the primary sedimentation tank It consists of a coagulation sedimentation tank connected downstream of the.

Hereinafter, the present invention will be described in detail with reference to embodiments of the wastewater treatment apparatus of the present invention shown in the accompanying drawings.

1 is a configuration diagram of a livestock wastewater treatment apparatus according to the present invention. The wastewater treatment device 10 includes a storage tank 20 for receiving wastewater that has undergone solid-liquid separation generated in a barn and supplying wastewater with a uniform concentration and flow rate, and anaerobicly activating dephosphorus microorganisms and flowing from the storage tank 20. An anaerobic fermentation tank 30 for hydrolyzing the hardly decomposable organic matter in the wastewater to be treated and a soil microbial carrier 42 serving as a source of microorganisms adaptable to high concentration wastewater are introduced and selectively activated, i.e., improved, aerobic microorganisms. In the microbial activator 40 and the wastewater treated by the anaerobic fermentation tank 30 in the mixing tank 50 for mixing the effluent from the microbial activator 40 and the return sludge, and in the wastewater introduced from the mixing tank 50. Mixed with an aeration tank 60 which decomposes and oxidizes organic matter and ammonia nitrogen by the metabolism of microorganisms, and nitrogen oxide of the aeration tank 60 treatment liquid Denitrification tank 70 for removing nitrogen by endogenous breathing action of the microorganisms contained therein, Multiple gradient settling tank 80 for solid-liquid separation of denitrified wastewater into solids and supernatant, and multiple gradient settling tank 80 It consists of a coagulation sedimentation tank 90 for removing residual phosphorus and solids from the supernatant, and a dehydrator 100 for dehydrating debris such as sludge generated in the coagulation sedimentation tank 90.

In addition, in the wastewater treatment device 10, the sludge of the first conveying path b and the denitrification tank 70 into which the microbial sludge of the aeration tank 60 flows into the microbial active tank 40 is introduced into the mixing tank 50. The 3rd conveyance path d which the microbial sludge of the 2nd conveyance path c and the multiple gradient type precipitation tank 80 flows into the anaerobic fermentation tank 37 is formed.

Then, the wastewater treatment device 10 has a fourth conveying path (e) flowing into the mixing tank 50 to treat the filtrate generated when the sludge is dewatered in the dehydrator 100, and the concentration of the storage tank 20 if necessary. The fifth conveying path (i) to which the treated water of the multiple gradient type settling tank 80 flows into the storage tank 20 is configured to control the pressure.

Before the treatment by the wastewater treatment apparatus 10 is performed, the livestock wastewater, manure, etc. generated in the barn etc. are first separated into a solid solution. The effluent from the solid-liquid separation contains high concentrations of organic matter including hardly decomposable organics, nitrogen and phosphorus. This wastewater is introduced into the storage tank 20 and stored. The storage tank 20 is, for example, about a two-day residence scale with respect to a flow rate of about 1.5 times the daily average flow rate of the wastewater, and, if necessary, of the multi-slope settling tank 80 introduced along the fifth conveying path i. The wastewater concentration is controlled by the treated water and then discharged at a constant concentration and flow rate. Wastewater maintained at a constant concentration is introduced into the anaerobic fermentation tank 30 along the path indicated by arrow a in FIG. 1 by a pump (not shown) or the like.

Figure 2 schematically shows the structure of the anaerobic fermentation tank 30. Anaerobic microorganisms are provided inside the anaerobic fermentation tank 30 to decompose organic matter contained in the wastewater introduced from the storage tank 20 by metabolic action of anaerobic microorganisms. In particular, the hardly decomposable organic matter contained in the waste water is hydrolyzed in an easy state for aerobic microorganisms to ingest, so that the phosphorus ingesting microorganisms release phosphorus in the body and store the organic material in the form of an organic acid as an energy source in the body. That is, in the wastewater treatment apparatus according to the present invention, the degree of loading of organic matter is appropriately controlled in the anaerobic fermentation tank 30 and a preparation mechanism for ingesting phosphorus in the aeration tank 60 is formed.

The anaerobic fermentation tank 30 shown in FIG. 2 is generally upright cylindrical with a first inlet 36 through which the wastewater enters from the storage tank 20 and from the multiple inclined settling tank 80 to secure dephosphorus microorganisms. A second inlet 37 through which sludge flows is formed along the third conveying path d, and an outlet 38 for discharging wastewater fermented in an anaerobic state is formed.

The wall of the anaerobic fermentation tank 30 is a thermal insulation wall 34 in which an electric coil (not shown) is built in to warm the inside of the anaerobic fermentation tank 30. An electric current is supplied to the electric coil in the heat insulating wall 34 to warm the inside of the anaerobic fermentation tank 30 to a predetermined temperature or more, so that the temperature of the wastewater discharged through the outlet 38 and the temperature of the activated dephosphorizing microorganisms described below. By maintaining at 30 ° C. or higher, it is possible to prevent efficiency degradation such as nitrification reaction due to low outside air temperature during subsequent processing in the aeration tank 60.

In addition, the mixing blade 32 for effectively mixing the anaerobic microorganism and the waste water is provided inside the anaerobic fermentation tank 30. Inside the anaerobic fermentation tank 30, a sludge discharge valve 35, a sludge discharge baffle 33 wave, and a scum crusher 31 are also provided. The sludge discharge valve 35 and the sludge discharge baffle 33 serve to discharge the sludge residue remaining inside the anaerobic fermentation tank 30. The scum crusher 31 acts to remove scum formed on the inner side of the anaerobic fermentation tank 30.

On the other hand, the sludge settled at the lower end of the multiple ramp type settling tank 80 described in detail below is conveyed into the anaerobic fermentation tank 30 along the third conveying path indicated by the arrow d in FIG. The dephosphorous microorganisms contained in the return sludge are activated under anaerobic conditions of the anaerobic fermentation tank 30 to release phosphorus (P) in the microbial cells in the form of phosphoric acid (PO ₄ ^3- ) and perform metabolism in the aeration tank 60. As an energy source for ingesting phosphorus, organic acids in the anaerobic fermentation tank 30 are accumulated in the body. The dephosphorous microorganisms in the aeration tank 60 ingest and remove much more phosphorus than the amount of phosphorus released from the anaerobic fermentation tank 30.

The anaerobic fermentation tank 30 is preferably operated to limit the number of days of dephosphorus microorganism retention to about 1.5 to 2.5 days so that anaerobic fermentation for organic acid production is maintained and methanation does not proceed.

3 is a schematic cross-sectional view of the microorganism activator 40 according to the present invention. A portion of the sludge containing the aerobic microorganisms is returned to the upper portion of the microorganism activation tank 40 and the outlet 46 through which the effluent water containing the aerobic microorganisms activated in the microorganism activation tank 40 is discharged. ) Is formed, and the disk diffuser 41 is provided at the bottom thereof. In addition, a lower portion of the microorganism activator 40 is provided with a valve 43 for discharging the debris inside the activator 40.

The sludge may be provided along the first conveying path indicated by arrow b in FIG. 1 from the outlet end of the aeration tank 60 as described in detail below. By introducing external air into the microorganism activator 40 through the diffuser 41, the interior of the microorganism activator 40 is maintained in an aerobic atmosphere, and only aerobic microorganisms in the sludge are selectively activated.

On the other hand, the inside of the microorganism activator 40 is provided with an inner activator 44 made of a porous wall, the inner activator 44 is a bacilli (bacillus) -based microorganisms and actinomycetes extracted from the soil and cultured independently A soil microbial carrier (or bioclade) 42 containing about 1% by weight of microorganisms such as actinomycets is introduced.

The microorganisms filled in the soil microbial carrier 42 are activated and grow under an aerobic atmosphere in the microorganism activator 40. Activated clad microorganisms are separated from soil microbial carrier 42 and discharged through outlet 46 together with activated aerobic microorganisms in microbial activator 40. In addition, since the microorganisms filled in the soil microbial carrier have a viability that is adaptable to high concentration wastewater, as described below, the microorganisms exhibit active metabolism even in contact with the high concentration organic matter in the aeration tank 60.

The return sludge introduced into the microorganism activator 40 may include microorganisms that prevent bulking, that is, solid-liquid separation, of the sludge, such as fungi including filamentous. The growth of these fungi is inhibited under an aerobic atmosphere in the microorganism activator 40 to facilitate the subsequent solid-liquid separation process. In addition, the microorganism that decomposes the organic matter may be operated in the aeration state in the microorganism activator 40 can improve its organic bioabsorption capacity. In order to maximize growth inhibition of microorganisms such as fungi and activation of aerobic microorganisms, the microorganism activator 40 is preferably operated with a residence time of about 1.5 to 2.0 days.

4 schematically illustrates the structure of the aeration tank 60. At one end of the aeration tank 60, the wastewater treated in the anaerobic fermentation tank 30 and the effluent from the microbial activator 40 and the return sludge from the denitrification tank 70 described later are mixed in the mixing tank 50. After the inlet 62 is introduced, the other end is formed with an outlet 64 through which the waste water treated in the aeration tank 60 is discharged. The bottom of the aeration tank 60 is inclined at an angle, for example, 7 °, in order to prevent sludge deposition in the aeration tank 60 and to facilitate the mixing action by the air supply. The interior of the aeration tank 60 is divided into a plurality of compartments by a plurality of separation membranes. The interior of the aeration tank 60 shown in the figure is divided into four compartments 60a, 60b, 60c, 6od by three separation membranes 66.

As the outside air flows into the aeration tank 60 through the air inlet pipe 61, the inside of the aeration tank 60 is maintained in an aerobic atmosphere, wherein the dissolved oxygen amount in the aeration tank 60 is 0.5 to 2.0 mg / L. Is preferably maintained.

On the other hand, when nitrification proceeds rapidly in the aeration tank 60, the amount of alkaline substance in the waste water may be a limiting factor of the nitrification process, so that the amount of dissolved oxygen in the aeration tank 60 may depend on the compartment in order to prevent such nitrification inhibition. It is kept at a different value. For example, the amount of dissolved oxygen in the first and fourth compartments 60a and 60d located at the inlet end of the aeration tank 70 in which the inlet 62 is formed and the outlet end in which the outlet 64 is formed is about It is maintained at 1.5 to 2.5 mg / L, and the dissolved oxygen amount in the second and third compartments 60b and 60c located between the inlet and outlet ends is maintained at 0.5 to 1.5 mg / L. In particular, the amount of dissolved oxygen in the second compartment 60b adjacent to the inlet end is maintained at 1.0 to 1.5 mg / L, and the amount of dissolved oxygen in the third compartment 60c adjacent to the outlet end is 0.5 to 1.0 mg / L. To keep. As such, by keeping the dissolved oxygen concentration in the aeration tank 60 relatively low, the aeration cost for the aerobic treatment can be minimized.

Decomposition, denitrification and dephosphorization of organic matter by metabolic action of aerobic microorganisms in the aeration tank 60 are as follows.

First, the aerobic microorganism is activated under the aeration conditions in the microorganism activator 40, and then enters the aeration tank 60 in a state where the bioabsorption capacity of the food ingredient is maximum. In the aeration tank 60, the organic matter decomposition process by metabolic action of aerobic microorganisms is represented by the following equation.

The growth of new cells according to the amount of BOD removed is about 0.5kg MLVSS / kg BOD rem.

On the other hand, ammonia nitrogen is nitrified as follows.

Nitrification of 1 mg / L ammoniacal nitrogen consumes 4.6 mg O ₂ / L of oxygen and 7.1 mg CaC0 ₃ / L of alkali. As described above, by adjusting the dissolved oxygen amount in the second and third compartments 60b and 60c located between the inlet and outlet ends of the aeration tank 60 to about 0.5 to 1.5 mg / L, in particular 1.0 mg / L, It inhibits rapid nitrification and prevents nitrification inhibition caused by lack of alkalinity.

It is common practice to vary the dissolved oxygen concentration in each compartment of the aeration tank. That is, the amount of blown air flowing into the four compartments from the blower through the air inlet pipes is used to adjust the dissolved oxygen concentration of each compartment by using the inlet valve for each air inlet pipe. The specific air flow for controlling dissolved oxygen in each compartment varies depending on the concentration load of organic matter and the characteristics of contaminants. Therefore, the amount of dissolved oxygen in each compartment is detected and detected by using a BO meter while operating the wastewater treatment system. As a result, by opening or closing the inlet valve, the amount of blown air flowing into each compartment is controlled to adjust the dissolved oxygen concentration.

The dephosphorization process in the aeration tank 70 is described as follows. The dephosphorous microorganism which released phosphorus in the cell in the form of phosphate in the anaerobic fermentation tank 30 consumes a relatively large amount of phosphorus when synthesizing the cells under an aerobic atmosphere in the aeration tank 67. For example, in the anaerobic fermentation tank 30, the amount of phosphorus (P) released by the dephosphorous microorganism in the form of phosphoric acid and the amount of phosphorus (P) ingested by the dephosphorous microorganism in the aerobic atmosphere in the aeration tank 60 are about 1: 1.5. is maintained at (ratio). Therefore, when cells of dephosphorus microorganisms are synthesized in the aeration tank 60, phosphorus (P) is excessively ingested in the cells (luxury uptake) to perform the dephosphorization process.

By using the dephosphorization microorganism selectively activated in the anaerobic fermentation tank 30 to improve the dephosphorization capacity of the wastewater treatment apparatus, the amount of chemicals required for the dephosphorization process through the coagulation treatment in the flocculation sedimentation tank 90 to be described later is minimized. The improvement can be improved.

In the process of decomposing organic matter by metabolic action of aerobic microorganisms in the aeration tank 60, a part of the sludge is represented by arrow b in FIG. 1 from the outlet 64 provided at the outlet end of the aeration tank 60. It is conveyed to the microorganism activation tank 40 along one conveyance path. Such conveying sludge contains aerobic microorganisms as described above. Waste water treated in the aeration tank 60 is introduced through the inlet 77 of the denitrification tank 70 in the anaerobic state through the outlet 64 in a mixed state with the microorganisms.

5 shows a denitrification tank 70 composed of a contact medium layer 70a and a mixed layer 70b. The contact filter layer 70a is filled with a contact filter 75 which performs denitrification on the mixed liquid aerated in the aeration tank 60. Nitrogen gas denitrated in the contact medium layer 70a in the mixed layer 70b is degassed, and the denitrified mixed liquid is discharged through the outlet 72 through the upper outlet weir 71.

The mixed solution of the microorganism and the wastewater introduced from the aeration tank 60 passes through the contact medium layer 70a having the contact medium 75 and is attached to the contact medium 75 which is microorganisms, and uses untreated organic matter and nitrate in the waste water. To perform the denitrification process and grow. As the microorganisms adhere to the contact medium 75, a sludge blanket is formed in the contact medium layer to perform a biological filter, thereby improving the solid-liquid separation effect of the wastewater and the sludge.

In the denitrification tank 70, the denitrification process is carried out through endogenous respiration of the concentrated microorganisms of the untreated organic material contained in the mixed solution introduced from the aeration tank 60 and the contact medium layer 70a using nitrogen oxide and sludge as follows. Do this.

That is, the denitrification process produces oxygen 2.86g O ₂ / g N and alkalinity 3.6g CaCO ₃ / g N, and the residence time of the denitrification tank is about 0.75 to 1.25 days, and the denitrification rate of this process is 0.03g N / g MLVSS / d.

In the denitrification tank 70, a part of the sludge is separated by filtration by biological filtration of the contact medium layer 70a and settles downward, and then the mixing tank 50 is formed along the second conveyance path c through the sludge outlet 76. Is returned. As a result, the concentration of microorganisms in the aeration tank 60 is kept constant.

The wastewater that has undergone the denitrification process is introduced into the multi-sloped sedimentation tank 80 at the bottom through the outlet 72 of the denitrification tank 70.

6 shows the structure of a multi-sloped settling tank 80, which includes a plurality of inclined settler plates 85 and a pair of inclined settler beds supporting both ends of the inclined settler plate and a lower settling sludge reservoir. Consists of.

In general, when the sludge residence time is long, such as a nutrient removal process, the cells are excessively oxidized and lose their activity, resulting in a fine cellular material that is dispersed and hardly settled, that is, pin floc. In order to remove such a pin floc, the multiple inclined sedimentation tank 80 is provided with multiple inclined sedimentation plates 85 therein, and is configured to expand the contact surface with the sludge.

The wastewater introduced into the multiple ramp type sedimentation tank 80 flows upward along the surface of the ramp settling plate 85 and flows along the surface of the next settling plate 85 over the settling plate 85. By providing a plurality of inclined precipitation plates 85, the contact surface of the sludge is expanded, and the occurrence of pin flocs is reduced.

After aeration and denitrification, the treated wastewater introduced into the multi-slope settling tank 80 is separated into solids and supernatant by gravity. This solid-liquid separation is enhanced by inhibiting the growth of fungi such as filamentus in the microbial activator 40 as described above. On the other hand, the solids are settled to the lower end in the multiple inclined sedimentation tank 80 and remain as sludge. The sludge is anoxic, and the dephosphorized microorganism with the residual concentration of nitric oxide almost zero becomes more dominant. This sludge flows into the anaerobic fermentation tank 30 along the third conveyance path d of FIG. 1 from the sludge discharge port 83 so that dephosphorus microorganisms in the sludge are activated.

The solid-liquid separated supernatant in the multiple inclined sedimentation tank 80 is introduced into the coagulation sedimentation tank 90 through the upper outlet 82 and chemically treated so that residual phosphorus and suspended solids are completely removed.

7 schematically shows the internal structure of the flocculation settling tank 90. The coagulation sedimentation tank 90 is provided with an introduction tube 92 through which the supernatant flows from the multiple gradient type precipitation tank 80, and an injection tube 94 for injecting chemicals such as sulfuric acid or metal salts. A wing 93 for properly mixing the supernatant introduced through the introduction tube 92 and the chemical introduced through the injection tube 94 is located at the bottom of the injection tube 94. In addition, inside the coagulation sedimentation tank 90, separation walls 96, 97, and 98 spaced apart at predetermined intervals are provided to form a mixing chamber, a coagulation chamber, and a precipitation separation chamber of a chemical and a supernatant.

Referring to the action in the flocculation sedimentation tank 90 in detail, the supernatant introduced into the flocculation sedimentation tank 90 through the introduction pipe 92 under the mixing action of the wings 93 is first sulfuric acid (H ₂ through the injection pipe 94). s0 ₄ ) is added and mixed to adjust the supernatant to a neutral, ie, pH of about 7.5. A predetermined amount of metal salt, for example iron salt, is injected and mixed into the neutralized supernatant through the injection tube 94. Thereafter, the mixed liquor removes residual phosphorus and suspended solids in the supernatant by a chemical reaction between the iron salt and the supernatant.

The reaction scheme in which residual phosphorus is removed is as follows.

That is, the residual phosphorus in the supernatant is directly reacted with iron (Fe) in the iron salt to be removed as an insoluble salt.

In addition, iron in the iron salt reacts with the hydroxyl group (OH ⁻ ) of the supernatant to form an iron hydroxide salt and precipitates out, as in the Daom Reaction Scheme.

At this time, the suspended solids remaining in the supernatant are coagulated and precipitated together due to the viscosity of the precipitated iron hydroxide.

Arrows displayed at the right half of FIG. 7 indicate a process in which the mixed solution of the supernatant and the chemical flows in the flocculation settling tank 90. Inside the dividing wall 96, while the blade 93 rotates, rapid mixing of the supernatant and the chemical is performed in the space defined by the dividing wall 96 for about 5 minutes. After that, the mixed energy thereof decreases as the mixed liquid passes over the distal end of the primary separation wall 96. Agglomeration of chemical sludge and growth of sludge particles proceed between the primary separation wall 96 and the secondary separation wall 97. As the mixed liquid exceeds the secondary dividing wall 97, the remaining mixed energy of the mixed liquid disappears, and as a result, the sludge of the mixed liquid precipitates through the terminal dividing wall 98. The final treated water generated in the coagulation sedimentation tank 90 is discharged to the outside through the baffle 99 installed on the top of the coagulation sedimentation tank 90 and is drawn out through the discharge port 91 installed in the lower portion of the coagulation sedimentation tank 90. And then to the dehydrator 100 along the path indicated by arrow h in FIG.

In the dehydrator 100, the sludge from the anaerobic fermentation tank 30 and the sludge from the multiple settling tank 80 are introduced together along the paths indicated by arrows f and g of FIG. The sludge introduced into the dehydrator 100 is dewatered and separated into dewatered sludge and dewatered filtrate. The dewatered sludge has a high organic content and contains little poisonous toxic substances, so that it can be recycled as a fertilizer through solid composting and the dewatered filtrate is introduced into the mixing tank 50 through the return path (e) of FIG.

[Test Example]

The livestock wastewater generated by the scraper type pig yarn was purified using the wastewater treatment apparatus of FIG. Table 1 below describes the specifications of the wastewater treatment apparatus used in this test example.

Here, a pH meter was used to measure the pH of the supernatant in the coagulation sedimentation tank 90, a transfer pump was used to transfer the wastewater in the storage tank 20 to the anaerobic fermentation tank 30, and a return pump was used in the apparatus. Was used to convey the sludge, and a mixing motor was used to rotate the mixing blades 93 of the mixing blades 32 and 73 and the flocculation settling tank 90 in the anaerobic fermentation tank 30 and the denitrification tank 70. The blower was used to supply air, especially oxygen, to the microbial activator 40 and the aeration tank 60. The livestock wastewater to be treated was diluted to adjust the biological oxygen demand (BOD) to 13,000 mg / L. At this time, the chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were 21,300 mg / L, 2,670 mg / L and 550 mg / L, respectively.

The soil microbial carrier 42 introduced into the microorganism activator 40 contained about 1% of the weight of the soil microbial carrier 42 by independently culturing Bacillus-based microorganisms and actinomycetes microorganisms.

The return rate from the denitrification tank 70 to the mixing tank 50 was 125%, and the rate of return of sludge from the multiple ramp type sedimentation tank 80 to the anaerobic fermentation tank 30 was 75%. The return rate of the sludge up to 40) was 100%. The dehydration filtrate was also conveyed entirely from the dehydrator 100 to the mixing tank 50. The volume of the entire apparatus except the reservoir 20 was 30.3 L and the air was blown between 15 and 20 L per minute.

Scum was formed about 10 days later in the upper portion of the anaerobic fermentation tank 30. The redox potential (ORP) value was found to be about -300 or less, and the soluble phosphorus content of the effluent was increased by about 1.5 to 2.2 times, and the soluble COD content was not significantly increased when considering the dilution effect by the return. However, the total nitrogen amount (TN) was reduced by about 32.6%, which significantly reduced the subsequent nitrogen load by pretreatment through the anaerobic fermenter 30, significantly reducing the amount of oxygen required for nitrification.

The microbial mixture of the aeration tank 60 was maintained at a concentration of about 11,000 to 14,000 mg / L, sludge production was about 0.5 kg MLVSS / kg BOD removed, and the discharge sludge concentration was about 18,000 mg / L. The dissolved oxygen content in the aeration tank 60 is 2.0 mg / L in the compartment 60a located at the inlet end, 1 to 1.5 mg / L at the compartment 60b close to the inlet end, and compartment 60c close to the outlet end. Was maintained at 0.5 to 1 mg / L, and at 2.5 mg / L in the compartment 60d located at the outlet end, and the pH in the aeration tank was 7.7 to 8.2. The alkalinity was about 2,325 mg as CaCO ₃ / L, which was reduced by nitrification, creating good conditions for the reduction of flocculant requirements for hydroxide formation during subsequent flocculation.

The effluent water quality of the multiple gradient tank 80 was BOD 128 mg / L, TN 145 mg / L and TP 75 mg / L. The BOD and TN showed high removal rates of over 95% and the TP removal rate was 86%. The outflow water quality of the coagulation sedimentation tank 90 in which the coagulation precipitation was performed by adding iron salt to the supernatant of the multi-gradient precipitation tank 80 was BOD 42mg / L, suspended solids (SS) 33mg / L, TN 45mg / L and TP 6.2mg. A stable water quality of / L was shown. At this time, the coagulated sludge is generated about four times the suspended solids (SS) of the multi-slope settling tank 80, the livestock wastewater by 13.6g / d and coagulated settling sludge 4.3g / d generated in the multi-slope settling tank 80 The sludge generated per COD removal was 0.4 kg SS / kg COD removed.

The treatment results of the livestock wastewater according to the present embodiment are shown in Table 2 below. The SVI of the microbial mixture of the aeration tank 60 during the treatment was 62 to 115, and the oxygen demand per hour was 58 to 105 mg O / L / hr, but the actual amount of oxygen supplied was about 360 mg O / hour when the oxygen transfer rate was 0.1. The dissolved oxygen concentration of the aeration tank 60 was kept low at L, but the required amount was satisfactory. Therefore, if there is no particular problem in the treated water quality, there is a significant savings in the treatment cost when the dissolved oxygen concentration is controlled as in the present invention.

Therefore, in the case of treating high concentration livestock wastewater according to the present invention, organic matter, nitrogen and phosphorus can be effectively and economically removed, thereby ensuring stable and excellent treated water economically. Therefore, the present invention is applicable to small-scale wastewater generating facilities and can effectively solve the environmental pollution problem associated with livestock wastewater. In addition, livestock wastewater treatment sludge can also be used as a solid fertilizer through composting, without concern for heavy metals or other hazardous contaminants, unlike in municipal sewage.

Claims (10)

Storing the effluent separated from the waste water in the storage tank to equalize the concentration and flow rate, and hydrolyzing and dephosphorizing the hardly degradable organic matter by the anaerobic microorganism in the anaerobic fermentation tank to facilitate the intake of subsequent microorganisms. Activating the microorganisms, activating the aerobic microorganisms to selectively improve only the aerobic microorganisms in the sludge returned from the aeration tank to the microbial activator tank, increase the bioadsorption capacity, and grow the microorganisms filled in the soil microbial carrier, Mixing the effluent of the contained microorganism activator with the anaerobic fermenter effluent, return sludge and desorption solution in a mixing tank, and treating the mixed solution in a dissolved oxygen concentration controlled aeration tank to treat organic matter and phosphorus and to nitrify ammonia nitrogen. Denitrification of the nitrates using the endogenous system, the liquid treated in the aeration tank using an endogenous respiration of microorganisms in anoxic state, and separating the denitrified liquid into sludge and supernatant in the primary sedimentation tank, and sedimentation separation in the primary sedimentation tank And removing the residual phosphorus and suspended solids from the supernatant from the supernatant and discharging the treated water. The wastewater treatment method according to claim 1, wherein the microbial activator comprises an internal activator filled with a soil microbial carrier. The wastewater treatment method of claim 1, further comprising supplying a portion of the microbial sludge separated from the primary settling tank to the microbial activator. The wastewater treatment method according to claim 1, wherein the treatment step of the aeration tank is performed in a multistage aeration tank, and the dissolved oxygen concentration in the middle stage of the aeration tank is adjusted to 0.5 mg / L to 1 mg / L. The wastewater treatment method according to claim 1, wherein the pH of the flocculation sedimentation tank is adjusted to 7.5 and iron salt is injected in the flocculation sedimentation tank treatment step. The wastewater treatment according to claim 5, further comprising solid-liquid separation of the settling sludge of the flocculation settling tank, the sludge discharged from the anaerobic fermentation tank and the sludge separated from the primary settling tank in a dehydrator, and the dewatered filtrate returned to the mixing tank. Way. A storage tank for storing solid-liquid separated waste water to equalize concentration and flow rate, an anaerobic fermentation tank located under the storage tank and having anaerobic microorganisms, an internal activation tank containing a soil microbial carrier, and a microorganism activation tank including an acid pipe; A mixing tank having an inlet through which the effluent and each of the anaerobic fermentation tank and the anaerobic fermentation tank flows, and returning sludge and dewatering filtrate, and receiving and mixing the inflows through the inlets, and a concentration-controlled aeration tank connected downstream of the mixing tank; And a denitrification tank connected to the downstream side of the aeration tank, a primary sedimentation tank connected to the downstream side of the denitrification tank, and an agglomeration sedimentation tank connected to the downstream side of the primary sedimentation tank. The wastewater treatment apparatus according to claim 7, wherein the aeration tank is a multi-stage aeration tank. 8. The wastewater treatment apparatus of claim 7, further comprising supply pipes for supplying dehydrator and sludge from each of said primary settling tank, flocculating settling tank and anaerobic fermenter to said dehydrator. 8. The wastewater treatment apparatus according to claim 7, wherein the denitrification tank and the anaerobic fermentation tank are separated and operated in order to eliminate the phenomenon of inhibition of dephosphorus microorganisms caused by nitric oxide.