KR19980068656A - Wastewater Treatment Using Biological Three-Phase Digestion Process in a Single Reactor - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method and apparatus for removing nutrients such as nitrogen, phosphorus, and high concentrations of organic matter contained in municipal sewage, animal husbandry wastewater, and organic phase industrial wastewater using metabolic properties and substrate reduction rates of microorganisms.

2. The technical problem to be solved by the invention

The present invention solves the problems presented in the conventional anaerobic / aerobic (A / O) wastewater treatment process and anaerobic / quasi-anaerobic / aerobic (A ² / O) wastewater treatment process, and combines the anaerobic treatment and semi-anaerobic treatment process of the wastewater. It can be carried out in a reactor to reduce the cost of process equipment and to remove phosphorus, and to manage the appropriate temperature at the time of anaerobic treatment and denitrification, and to manage the carbon nutrient source necessary for denitrification by itself. The purpose is to provide a wastewater treatment method that can be supplied.

3. Summary of the Invention

In order to achieve the above object, the present invention sequentially introduces the incoming wastewater treated with sedimentation at the first settling place into the reaction tank (1 ') through the incoming wastewater pipe (2) in order to sequentially produce the acid (3) and the methane production step. After undergoing anaerobic treatment through (4), the anaerobic filter (9 ') formed in the upper portion of the reaction tank (1') undergoes a quasi-anaerobic process, which is denitrified, and then flows into the aerobic tank (10) for aerobic treatment. The aerobic wastewater mixture is transferred from the aerobic tank (10) to the settling tank (11), after which the supernatant is discharged, and a portion of the precipitated sludge is returned to the reactor (1 ') through the sludge conduit (14). Nitrogen oxide generated by aerobic treatment from the aerobic tank 10 is mixed with the incoming wastewater and introduced into the quasi-anaerobic media (9 ') formed in the upper portion of the reaction tank (1') through the nitric oxide conduit (13). Organisms in a single reactor Provided is a wastewater treatment method using a three-phase digestion process.

4. Important uses of the invention

The present invention has a use for the treatment of municipal sewage, livestock wastewater and organic phase industrial wastewater.

Description

Wastewater Treatment Using Biological Three-Phase Digestion Process in a Single Reactor

The present invention relates to a method for removing nutrients such as nitrogen, phosphorus and high concentrations of organic matter contained in municipal sewage, livestock wastewater, and organic phase industrial wastewater using metabolic properties and substrate reduction rates of microorganisms. The biofilm process is applied to the conventional A ² / O (anaerobic-quasi-aerobic) treatment process to form an acid formation step, a methane formation step and a denitrification reaction step in a single reactor to maintain an appropriate reaction temperature. Wastewater treatment method using a biological three-phase digestion process in a single reactor that can facilitate the use of an internal carbon source in denitrification reactions and can improve phosphorus removal efficiency by inhibiting nitrogen oxide inflow during anaerobic treatment of wastewater. It is about.

In recent years, with the improvement of national living standards and the rapid development of industry in all fields, environmental pollution as a counter-payment has been seriously raised, especially urban sewage, which shows an exponential increase in the amount of generation. Water pollutants such as wastewater and industrial wastewater present many problems such as ecosystem destruction.

In general, pollutants such as industrial wastewater and municipal sewage contain not only organic pollutants but also nutrients such as nitrogen and phosphorus.As a method for removing organic pollutants, the conventional activated sludge method and anaerobic digestion are conventionally used. Construction methods are mainly used.

However, since nutrients such as nitrogen and phosphorus, except for organic pollutants, are not treated well by conventional methods, they are mostly discharged as untreated, resulting in eutrophication of surface water and deterioration of drinking water quality.

For this reason, researches on chemical and biological methods for removing nutrients such as nitrogen and phosphorus from raw waste water have been introduced, and chemicals for removing nitrogen from raw waste water from which organic contaminants have been removed by the standard activated sludge method have been introduced. The methods include a method of selectively replacing ammonia ions through an ion exchange column, a method of increasing the pH to change ammonia to a free ammonia state, and then oxidizing it in a degassing column to volatize it to a gaseous state.

In addition, as a method for removing phosphorus by chemical low, coagulation sedimentation which precipitates and removes phosphorus present in soluble phosphoric acid [PO ₄ ^3- ] in the raw wastewater by using ferric chloride, aluminum sulfate or slaked lime as coagulant manufacturing agent. Law, etc.

However, the above-described chemical nutrient removal method has a problem in that the efficiency of the treatment process decreases, and in order to lower the concentration of the nutrient substance in the treatment liquid to a satisfactory state that will exhibit the anti- eutectic effect, There is a problem of economical because it must be used, the treatment material after completing the chemical treatment process has a problem that remains as a secondary pollutant.

Therefore, in recent years, a biological treatment method using microorganisms has gained much attention as a method for removing nutrients such as nitrogen and phosphorus contained in raw wastewater in consideration of the problems of the chemical treatment method.

Biological nitrogen removal is based on nitrification / denitrification, which oxidizes ammonia nitrogen to nitric acid by nitrifying microorganisms, and then denitrifies microorganisms under anoxic or semi-anaerobic conditions without molecular oxygen (O ₂ ). It is a method to remove by changing to nitrogen gas by means of biological dephosphorization method. The biological dephosphorization method is a modified biological dephosphorization method. The basic principle of this method is that microorganisms in the sludge release phosphorus under anaerobic conditions and are aerobic. Under the conditions, poly-P microorganisms utilize the phenomenon of luxury uptake of phosphorus by decomposing organic substances in sludge.

Examples of methods applying the biological nutrient removal principle include postrip, Badenpho process, and anaerobic / aerobic treatment, among which anaerobic / aerobic treatment. The method is one of the most widely used wastewater treatment methods because it is very similar to the standard activated sludge process and the process itself is very simple compared to other methods.

In this anaerobic / aerobic (A / O) treatment method, the returned activated sludge is mixed with the inflow wastewater, and then passed through the anaerobic tank via the aerobic tank so that the phosphorus contained in the sludge is eluted under anaerobic conditions, and the phosphorus accumulates in the aerobic condition. Excessive consumption and consumption by the microorganisms ultimately removes excess sludge containing high concentrations of phosphorus and ultimately removes phosphorus from the wastewater.

However, the anaerobic / aerobic (A / O) method was developed mainly for the removal of phosphorus from nutrients present in the wastewater, and if the nitrogen oxide produced from the aerobic tank was introduced into the anaerobic tank for nitrogen removal, Phosphorus elution in the anaerobic tank is hampered by the action of nitrogen, which leads to the problem that phosphorus removal is not carried out by the accumulation of microorganisms in the aerobic tank.

Anaerobic / quasi-aerobic / aerobic (A ² / O) treatment process has been introduced as a method to improve the problems of anaerobic / aerobic (A / O) process, and such anaerobic / quasi-aerobic / aerobic (A ² / O) process was introduced. The process consists of a separate anaerobic tank for denitrification between the anaerobic tank and the aerobic tank so that nitrogen oxides for nitrogen removal can be directly introduced into the semi-anaerobic tank, which not only leads to phosphorus removal and denitrification during wastewater treatment, but also It has the advantage of reducing the effects of nitric oxide on phosphorus elution in anaerobic conditions.

An example of a conventional treatment process associated with this will be described with reference to the accompanying drawings.

1 shows a conventional anaerobic / quasi-anaerobic / aerobic (A ² O) treatment process diagram, wherein the incoming wastewater treated first through the most sedimentation basin (not shown) is settled through the inlet wastewater pipe (2). (11) is mixed with the sludge conveyed through the sludge guidance pipe (14) and flows upward at a proper flow rate into the reaction tank (1) in which the inside is kept anaerobic, and the introduced wastewater mixture is flowed upward in the reaction tank (1). The organic matter contained in the wastewater mixture is sequentially decomposed by the acid producing microorganisms and the methane producing microorganisms suspended in the reactor 1 through the acid producing step (3) and the methane producing step (4). After the stabilization process, the gas, such as methane and carbon dioxide generated from the acid generation step (3) and the methane production step (4) while passing through the gas-solid separation device (6) configured in the upper portion of the reaction tank (1) mix Separated from the sludge contained in the collected by the gas outlet (7) and collected in the gas collection tank (8), the degassed wastewater mixture is introduced into the quasi-anaerobic tank (9), from the aerobic tank (10) After the nitrogen oxide conduit (13) is mixed with the nitrogen and the acidic nitrogen to be returned to the quasi-anaerobic tank (9) (12) through an anaerobic process that is denitrified by denitrifying microorganisms to the aerobic tank (10) The wastewater treatment liquid introduced and introduced into the aerobic tank 10 is aerobic treated by aeration or the like, so that a part of the nitrogen oxide produced is returned to the quasi-anaerobic tank 9 through the nitric oxide conduit 13 and at the same time. The wastewater mixture containing the microbial sludge ingesting excessive phosphorus in the treatment process is transferred from the aerobic tank 10 to the settling tank 11, and the supernatant is discharged, and a part of the sludge deposited is passed through the sludge guide tube 14. Reactor (1) The transmission comprises a step of repeating the process described above by being lead-based waste water (2) and the mixture inlet.

In the above process, the high-rate anaerobic reaction in the reaction tank (1) and the quasi-anaerobic denitrification reaction in the semi-anaerobic tank (9) are carried out at the concentration and characteristics of the substrate (pollutant) given at the reaction, the amount and type of microorganisms, and the metabolism. Environmental factors such as path and reaction temperature determine whether the treatment is efficient.

In particular, the reaction temperature is a major influence factor that greatly affects the overall removal efficiency of contaminants such as high rate anaerobic treatment efficiency and denitrification efficiency, and it is preferable that the optimum temperature during anaerobic reaction and denitrification is maintained at 35 to 50 ° C. Known.

In this regard, in the conventional anaerobic / quasi-anaerobic / aerobic (A ² / O) treatment process, the heating device 5 is configured on one side of the reactor 1 to maintain a proper temperature, which corresponds to a high rate anaerobic process. Only the reaction temperature in the reaction tank (1) can be controlled, and the reaction tank (1) and the quasi-anaerobic tank (9) are configured in a separate state according to the purpose of removing organic matter and nitrogen to perform the treatment process for the denitrification reaction. The quasi-anaerobic tank is affected by the change in the external temperature, and particularly has a problem that the denitrification efficiency is rapidly reduced at low temperatures in winter. In order to compensate for this problem, if the device for heating separately in the semi-anaerobic tank (9), there is a problem that additional installation cost.

In addition, nitric oxide introduced from the aerobic tank (10) is denitrified by microorganisms in the sub-anaerobic tank (9), and the involved microorganisms are random heterotrophic microorganisms (Heterotorophs) in the process. In the related art, organic carbon sources 12, such as methanol and acetic acid, have to be injected from the outside, so that the organic carbon sources as pure chemicals have a relatively expensive relationship, resulting in an excessively expensive process cost.

The present invention is to solve the problems in the conventional anaerobic / aerobic (A / 0) and anaerobic / semi-anaerobic / aerobic (A ² O) treatment process, to form a biofilm media in the upper region of the anaerobic reactor By using this as a semi-anaerobic tank for denitrification, the three-phase treatment process of the anaerobic process including the acid formation step, the methane generation step, and the semi-anaerobic step including the denitrification step can be performed in a single reactor. The process can be shortened, it is easy to maintain and manage the reaction temperature of the denitrification process properly, and the nitric oxide nitrified from the aerobic treatment process for denitrification in the conventional anaerobic / aerobic (A / 0) is anaerobic. The present invention provides a wastewater treatment method using a biological three-phase digestion process in a single reactor to prevent phosphorus elution from being inhibited when directly introduced into the reactor. There is an enemy.

Conventionally, an upflow anaerobic bed filter process of filtering activated sludge from wastewater flowing upstream in an anaerobic reactor by forming a filter on the upper part of the anaerobic reactor has been introduced, but this is simply an activity in wastewater. It is for the function as a solid-liquid separator to prevent sludge from leaking out of the anaerobic reactor, and the technology for the process of denitrification by using it as a biofilm medium for carrying out the anaerobic reaction has been introduced. There is no bar.

1 is a conventional anaerobic / quasi-anaerobic / aerobic (A ² / O) wastewater treatment process diagram

2 is a wastewater treatment process diagram of the present invention

FIG. 3 is an electron micrograph of Metanotrix

* Description of the symbols for the main parts of the drawings *

1,1 ': reactor 2: retracted wastewater pipe

3: methane production step 4: acid production step

5: Heating device 6: Gas-solids separation device

7: gas outlet 8: gas collection tank

9: quasi anaerobic composition 9 ': junhyeong media

10: aerobic maturation 11: sedimentation tank

12: external organic carbon nutrition source 13: nitric oxide conduit

14: Slaughter Leader

When described in detail with reference to the accompanying drawings, a preferred embodiment of the present invention for achieving the above object is as follows.

Figure 2 shows an example of the wastewater treatment process of the present invention, the first incoming sewage treated in the first sedimentation basin (not shown in the drawing) is introduced upwardly into the reactor (1 ') through the incoming wastewater pipe (2) The anaerobic process is sequentially anaerobic while undergoing the acid production step (3) and methane production step (4), and then enters the quasi-anaerobic filter (9 ') configured at the top of the reactor (1'). After coarse, the aerobic tank (10) is introduced into the aerobic treatment, and the aerated wastewater mixture is transferred from the aerobic tank (10) to the sedimentation tank (11), after the sedimentation process, the supernatant is discharged, and a portion of the sludge deposited is sludge conduit pipe. (14 ') is returned to the reaction tank (1') and mixed with the incoming wastewater, and the nitric oxide produced by the aerobic treatment from the aerobic tank (10) through the nitrogen oxide conduit (13) the upper portion of the reaction tank (1 ') Mixed inflow into quasi-anaerobic media (9 ') It is so configured.

The wastewater treatment process of the present invention having the above configuration will be described in more detail in terms of effect.

The incoming wastewater treated primarily through the maximum settling basin (not shown in the figure) is mixed with the sludge returned from the settling tank 11 through the sludge conduit 14 through the incoming wastewater conduit 2 so that the interior is anaerobic. Inflowed upward into the reactor (1 ') maintained as, the introduced mixed liquid is flowed upward in the reactor (1') and sequentially contained in the waste water mixture through the acid production step (3) and methane production step (4) Organic matter is decomposed by acid-producing microorganisms and methane-producing microorganisms suspended in the reactor 1 'and undergoes an anaerobic treatment process that produces and stabilizes acetic acid, methane and carbon dioxide.

The anaerobic treatment described above includes a process in which organic matter in the wastewater mixture is decomposed and stabilized by microorganisms and phosphorus is eluted from the activated sludge to dissolved phosphorus.

At this time, in order to increase the initial operating efficiency of the reaction tank (1 '), the non-granule or granule sludge composed of digested sludge and activated sludge is planted in advance in the lower part of the reaction tank (1'). It is preferable to have a solid concentration of 60 to 70 g VSS / L, and the seeding amount is sufficient to be about 10 to 20 gr VSS / L based on the reactor volume.

Therefore, the sludge conveyed from the incoming wastewater and the sedimentation tank 11 through the sludge guidance pipe 14 enters the reaction tank 1 'and passes through the seeded sludge layer, and is primarily subjected to the acid production step (3). At this time, organic substances contained in the wastewater mixture by acid-producing bacteria such as Pseudomonas, Flaboactactium, Flacalibacterium, Alcaligenes, Escherichia and Aerobacter are propionic acid. , Butanoic acid, long chain fatty acids or aromatic aldehydes and the like.

The compound decomposed by the above process is converted into acetic acid and hydrogen by heteroacetogenic bacteria in acid production step (3) and acetic acid is converted back to methane and carbon dioxide in methane production step (4), which is a subsequent anaerobic treatment step. By decomposition, acetic acid production rate directly affects methane production rate.

Therefore, if the partial pressure of hydrogen generated together with acetic acid as a product during the acid formation reaction is adjusted to 10 ⁻⁴ atm or less in the reactor 1 ', the ΔG ⁰ value of the total acetic acid production reaction is maintained at a negative value. In terms of acetic acid production reaction can proceed smoothly, resulting in an overall anaerobic treatment efficiency, including methane production rate.

The wastewater mixture containing acetic acid produced in the acid production step (3) is upflowed from the bottom acid production step (3) of the reaction tank (1 '), as described above, and the acetic acid is reacted with methane by methanogenic bacteria. The carbon dioxide is decomposed into carbon dioxide and reacted with hydrogen again to undergo a methane production step (4), which is generated from methane and water.

Since methane producing bacteria are very sensitive to oxygen and are easily killed when they come in contact with oxygen, the redox potential in the reaction tank (1 ') is about 300 mV, and when the reaction environment is maintained in an absolute anaerobic state, the growth of methane producing bacteria is prevented. I can promote it.

During the anaerobic treatment of the acid formation step (3) and methane formation step (4), the metabolism and organic matter metabolism by the phosphorus-removing microorganism is also progressed, and the phosphorus metabolism of these microorganisms is introduced from the precipitation tank 11 Phosphorus present in the sludge is released to the wastewater mixture and is present as soluble phosphorus, thereby increasing the phosphorus concentration in the wastewater mixture.

The wastewater mixture treated from the above anaerobic treatment flows upwardly and flows into the lower part of the quasi-anaerobic medium (9 ') formed at the top of the reaction tank (1'), and at the same time, the aerobic tank (10) exhales by aeration or the like. Nitrogen oxide treated and converted from ammonia nitrogen to nitrate nitrogen (NO _X ) is returned through the nitric oxide conduit (13) and simultaneously introduced into the lower portion of the quasi-anaerobic medium (9 '). As a result of the reduction, a quasi-anaerobic denitrification reaction is decomposed into nitrogen gas (N ₂ ).

At this time, nitric oxide is not anaerobic mediated without being reversed to the bottom by the upflow of the wastewater mixture which has undergone anaerobic treatment at the bottom of the reactor 1 'and the strong synergistic application of methane gas generated from the anaerobic treatment. Direct entry into (9 ') does not occur when nitric oxide inhibits the anaerobic environment under the reactor (1').

Denitrification microorganisms include Pseudomonas, Micrococcus, Achromobacter and Bacillus, all of which require an organic carbon source as an electron donor during denitrification. In the present invention, the organic matter (floating sludge) filtered through the quasi-anaerobic filter (9 ') and the by-product of anaerobic treatment process are raised as untreated in the anaerobic treatment process under the reactor (1') to the quasi-anaerobic filter (9 '). By using the introduced methane gas, it is not necessary to separately inject organic carbon sources such as methanol and acetate from the outside.

In the quasi-anaerobic media (9 '), along with denitrification microorganisms, some anaerobic microorganisms, such as methane-producing microorganisms, are attached and grown, and methane production reaction is performed along with denitrification. A photograph of Methanotrix micrograph of one treatment liquid to verify the existence of the methane-producing bacteria, which is the standard free energy (ΔG ⁰ ) value in the reaction of the electron acceptor of methane-producing bacteria under anaerobic conditions. for O ₂₎ -25.28 kcal, nitrate ion (NO ₃ ^- in) in the case of -23.74 kcal, a sulfate ion (SO ₄ ^2-) -1.52 kcal, acetate ion (CH ₃ COO ^- in) as -0.85 kcal the reduction rate _{O 2> NO 3> SO 4} 2-> CH 3 COO - in competition for the electron acceptor substrate that is held in the interior of the semi-anaerobic filter material (9 '), given that appears in the order according to the denitrification micro-organisms Full denitrification can occur Means.

As the quasi-anaerobic media (9 ') in which such a quasi-denitrification reaction occurs, a bio-chemically stable material is used, and a reticulated media having a Luffer or lock type to secure a large number of adherent microorganisms is preferable. In addition, the specific surface area and porosity of the media is preferably larger than that of the general plastic media, and the specific surface area and the porosity of the media is preferably somewhat larger than that of the general plastic media, but this is not particularly limited. Can change with speed.

Meanwhile, quasi-anaerobic media (9 ') Nitrogen gas, carbon dioxide gas, and excess methane gas generated from the denitrification reaction in the interior are collected by the gas outlet 7 and collected in the gas collection tank 8, and the wastewater mixed solution of the filtrate is transferred to the aerobic tank 10. do.

During the anaerobic treatment process of the acid production step (3) and the methane production step (4) and the quasi-anaerobic denitrification reaction in the quasi-anaerobic filter (9 '), the heating device (5) configured at one side of the reaction tank (9') By being warmed by the above, the temperature at the time of anaerobic and quasi-anaerobic reaction can be maintained at a minimum temperature of 34 to 35 ° C. or a high temperature of 50 to 55 ° C.

Subsequently, the wastewater mixed liquor of the filtrate transferred to the aerobic tank 10 flows into the settling tank 11 after an aerobic treatment process such as aeration, and during this process, a part of the treatment liquid containing nitric oxide is nitric oxide conduit ( It is returned to the reactor 1 'through 13) and flows upward as a lower part of the quasi-anaerobic filter 9' as described above.

In the aerobic tank 10, an oxidation reaction occurs in which the ammonia nitrogen present in the wastewater mixture is converted into nitrate nitrogen by nitrifying microorganisms such as nitrosomonas and nitrobacter, wherein the dissolved oxygen ( DO) concentration should be maintained above 1mg / L, and when the concentration of dissolved oxygen (DO) is lowered below 1mg / L, nitrification will be slowed or stopped.

In the aerobic treatment process in the aerobic tank 10, the phosphorus is eluted during the anaerobic treatment of the acid formation step (3) and methane formation step (4) that has been advanced in advance with the nitrification reaction, the content of intracellular phosphorus is higher than that of the general aerobic microorganisms. A process of ingestion of phosphorus, in which microorganisms such as Ecinetobacter ingests excessively soluble phosphorus present in the wastewater mixture and stores it in the form of poly-P, is simultaneously performed.

Therefore, the microorganism activated sludge flowing into the sedimentation tank 11 contains a high concentration of phosphorus and by removing these activated sludges, the ultimate phosphorus removal in the entire wastewater treatment process is completed.

Finally, the wastewater mixture is introduced into the sedimentation tank 11, the sludge contained in the wastewater mixture by gravity sedimentation is settled to the lower portion of the sedimentation tank 11, the supernatant of the upper portion of the sedimentation tank 11 is discharged to the outside, Some of the sludge precipitated in the lower portion is returned to the reactor 1 'through the conduit 14 and then mixed with the incoming wastewater 20 to repeat the previously described wastewater treatment process.

Nitrogen oxide may be contained in the sludge conveyed to reaction tank 1 '. A small amount of nitric oxide is consumed soon after mixing with the wastewater mixture, but when the amount is large, the anaerobic state of the reaction tank 1 'can be impaired and the phosphorus elution can be inhibited, so the residence time in the settling tank 11 is reduced. By adjusting for a long time, residual nitric oxide components can be removed.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

<Example>

Swine wastewater was collected from a livestock farm in Chuncheon, Gangwon-do, and settled for 2 hours at the initial sedimentation site. The properties are shown in Table 1 below.

TABLE 1

The characteristic values of the wastewater shown in Table 1 indicate the average characteristics of the wastewater used during the operation period, and the treatment facility of the present invention for the experiment of the wastewater having such a characteristic has a configuration as shown in FIG. 2.

In other words, the anaerobic reactor was made of a circular acrylic tube having an inner diameter of 9 cm and a height of 155 cm as an upflow system of wastewater injection. The total volume of the anaerobic reactor is 6.68L and the effective volume is 6.0L except 10cm of upper margin. The lower 60cm of the anaerobic reactor is in the form of Upflow Anaerobic Sludge Blanket (UASB), in which granules of microorganisms can be formed, and the upper 35cm is a reticulated S / L ^TM (Sun Lock). The media was filled with a size of 5 cm x 5 cm. In addition, a collecting device was installed in the upper part of the reaction tank where gas was discharged, and the wastewater was injected using a micro pump. The anaerobic reactor was warmed externally by a heating bar, and air was mixed by injecting air into the heating tank to maintain an even temperature.

In the lower part of the anaerobic reactor, 4L of soda sludge was planted in advance, and TS of digested sludge was 31.2g / L and VS was 17.2g / L.

In addition, the nitrification tank installed after the anaerobic reactor has two square acrylic reactors of 11cm × 16cm × 30cm and a diffuser is installed inside, and the effective volume is 14.3L. A pump was installed so that part of the effluent was returned to the biofilm media of the anaerobic reactor.

Finally, 2L sedimentation tank was installed for sedimentation of the effluent from the nitrification tank, and a pump was installed to return a part of the sedimented sludge to the anaerobic reactor.

The operating conditions in the treatment are shown in Table 2 below.

TABLE 2

The results of the experimental treatment under the operating conditions of Table 2 are shown in Table 3 below.

TABLE 3

<Comparative Example>

Table 4 shows the results of the conventional anaerobic / aerobic activated sludge method using the wastewater having the same properties as those of Table 1 under the operating conditions of Table 2.

TABLE 4

As can be seen from the results shown in Table 3 of the Example and Table 4 of the Comparative Example, the wastewater treated by the conventional anaerobic / aerobic (A / O) method is suspended solids (SS), chemical oxygen demand (COD). ), And the removal rate of organic matters such as BOD is shown to be more than 90%, while the removal efficiency of nutrients nitrogen and phosphorus is very low.

That is, the removal efficiency of the total Kjeldahl nitrogen (TKN) and ammonia nitrogen (NH ₃ -N) of the waste water treated by the conventional anaerobic / aerobic (A / O) method shown in Table 4 is due to aeration, such as aerobic conditions It shows the removal rate of nitrogen that can be removed by nitrification by 88.9% and 88.2%, respectively, but the removal efficiency of total nitrogen (TN) removed by denitrification in the whole treatment process is 58.9%. Appearing low.

It is considered that this is because only nitrogen removal by cell synthesis and degassing of the microorganism was performed in the state that the reaction of nitric oxide for denitrification was not formed during the treatment process.

In addition, the removal rate of total phosphorus (T-P) is also very low, which is 26.3%, because it was introduced into the sludge in a large amount into the final nitrification tank under aerobic conditions, and thus it was found to have an adverse effect on the dissolution of phosphorus.

However, in the wastewater treated by the method according to the present invention as shown in Table 3, the treatment efficiency of total Kjelda nitrogen (TKN) and ammonia nitrogen (NH ₃ -N) is very high, 91.1% and 92.3%, respectively. In addition, the removal rate of total nitrogen (TN) was 78.7%, which is about 20% higher than that of the comparative example. This high nitrogen removal rate is completely denitrification in the quasi-anaerobic media formed in the reactor. It is judged that it is authorized from being performed.

On the other hand, the total phosphorus (TP) removal rate of the wastewater treated by the method according to the present invention was also shown to be 63.9%, which is about 37.6% higher than in the comparative example, which is an oxidation introduced into the quasi-anaerobic media in the reactor during the denitrification reaction. Nitrogen is not backflowed into the anaerobic reaction stage under the quasi-anaerobic media, meaning that it does not inhibit citation by the microorganisms under anaerobic conditions.

In addition to nutrients such as nitrogen and phosphorus, organic matter removal efficiency such as suspended solids (SS), chemical oxygen demand (COD), and biological oxygen demand (BOD) is also shown to be higher than 90%, as well as conventional anaerobic / aerobic (A It is understood that it is superior to the result in the comparative example treated with the / O) method.

As described above, the present invention can not only perform the anaerobic treatment and semi-anaerobic treatment process of the waste water in a single reaction conditions by developing a wastewater treatment process to configure the anaerobic mediator in the anaerobic reactor to have the function of the denitrification tank It is a useful invention to provide a wastewater treatment method that can be managed in a batch of the appropriate temperature at the anaerobic treatment and denitrification treatment, and can supply the carbon nutrient source necessary for the denitrification treatment to reduce the production cost significantly.

Claims (2)

In the wastewater treatment, the incoming wastewater precipitated at the initial sedimentation basin is introduced into the reactor (1 ') through the incoming wastewater pipe (2) in order to sequentially undergo an acid production step (3) and a methane production step (4). After the treatment, the anaerobic filter (9 ') formed in the upper part of the reaction tank (1') undergoes a semi-anaerobic process that is denitrified by flowing into the aerobic tank (10), and then aerobic treatment, aerobic wastewater mixed solution After the silver aerobic tank (10) is transferred to the sedimentation tank (11) and settled, the supernatant is discharged and a portion of the precipitated sludge is returned to the reaction tank (1 ') through the sludge conduit pipe (14) and mixed with the incoming wastewater. Nitrogen oxide produced by the aerobic treatment from the aerobic tank 10 is mixed inflow into the quasi-anaerobic medium (9 ') configured in the upper portion of the reaction tank (1') through the nitric oxide conduit (13) in a single reaction tank Biological three-phase digestion process Wastewater treatment method. The anaerobic reaction and quasi-anaerobic mediator (9 ') comprising the acid production step (3) and the methane production step (4) by forming a heating device (5) on one side of the reaction tank (1'). Wastewater treatment method using a biological three-phase digestion process in a single reactor, characterized in that the reaction temperature of the quasi-anaerobic reaction including the denitrification reaction in a batch.