KR20010088714A - Method and Apparatus Removing Nitrogen and Phosphorus from Waste Water - Google Patents

Abstract

PURPOSE: An advanced biological treatment method of sewage and wastewater is provided, which can increase treatment efficiencies of BOD, SS, T-N and T-P to 96.5%, 97.6%, 65% and 53.6% that are much higher than 79%, 81%, 20% and 13% of conventional method and can reduce sludge generation to 2 kg per 100 cubic meter that is 4-5 times lower than 8.5 kg per 100 cubic meter of conventional method. CONSTITUTION: The method is as follows: (i) a settling and screening tank (10) for settling and removing solid contained in influent wastewater; (ii) a contact anaerobic tank (20) for easing flow load of screened wastewater, for releasing phosphorus at anaerobic condition and for removing organic matter; (iii) a first chamber (31) of a contact periodic aeration tank for removing the released phosphorus and organic matter during aeration and for denitrifying using influent organic matter during non-aeration; (iv) a second chamber (32) of the contact periodic aeration tank for nitrification and denitrification during periodical aeration and non-aeration; (iv) a contact continuous aeration tank (33) for continuous aeration to nitrifying the residue organic matter; (v) a final settling tank (40) for settling the proliferated sludge and for sending the supernatant to the next process and sludge to the second contact aeration chamber (32); and (vi) a sterilizing and discharging tank (50).

Description

Method for removing nitrogen and phosphorus from sewage and wastewater and its removal device {Method and Apparatus Removing Nitrogen and Phosphorus from Waste Water}

The present invention relates to a method and apparatus for removing nitrogen and phosphorus from sewage and wastewater, and more specifically, a floating / attachment reaction tank for removing nutrients and organic substances such as nitrogen and phosphorus dissolved in sewage and wastewater. The present invention relates to a higher order processing method and a device thereof by the periodic abandonment method.

As used herein, the terms "wastewater", "sewage", "influent" and "sewage / wastewater" are used in the same sense.

In Korea, we are operating the sludge process, which is the secondary treatment, focusing on the removal of organic matter in water treatment. Nitrogen and phosphorus dissolved in sewage and wastewater are almost untreated, and are discharged to rivers or flow into lakes and reservoirs. As a result, nutrients (nitrogen and phosphorus) were almost unprotected against eutrophication by the inflow of lakes.

Therefore, in order to solve such a problem, a process for simultaneously treating nutrients of nitrogen and phosphorus by a physical, chemical or biological unit process has been developed, but the treatment process is independent, and how to properly apply it in the process is a problem.

First, in view of the principle of removing BOD and suspended solids (SS), under aerobic conditions, aerobic microorganisms (oxidative bacteria) oxidize and decompose organic substances in sewage to obtain energy, and synthesize new protoplasts using these energies.

Microorganisms are also oxidatively decomposed by self-oxidation (endogenous breathing). Here, the cell material which is not oxidatively decomposed by endogenous respiration becomes excess sludge. This step removes BOD and suspended solids (SS).

On the other hand, the principle of phosphorus removal shows that phosphorus requires a small amount compared to carbon or nitrogen for the growth of microorganisms, and thus it is not possible to obtain satisfactory results by the method of cell synthesis. The use of the phenomenon has been studied to effectively remove phosphorus more than the biochemical equivalents required for various metabolism of microorganisms.

Phosphorus-removing microorganisms consume organic energy such as acetic acid by using the energy generated when decomposing inorganic phosphorus (Poly-P) accumulated in the cell under anaerobic conditions, and then convert it into PHB (Poly-β-Buthylate) and store it. In this case, the free phosphoric acid liberated is released into the solution, which is called "release of phosphorus".

If anaerobic conditions are converted to aerobic conditions, the phosphorus-removing microorganism decomposes the stored PHB to synthesize ATP, and by using it, ingests phosphoric acid from the solution, synthesizes inorganic phosphorus, and stores it in cells. This phenomenon is called "Phosphorus Luxuary Uptake."

Meanwhile, 0.8 mg of volatile organic acid (VFS, Volatile Fatty Acid) is required to remove 1 mg of phosphorus for proper biological phosphorus removal.

In case of shortage in the raw waste water itself, the primary settling sludge is hydrolyzed in anaerobic phase at 20 ~ 25 ℃ for 1 ~ 3 days, and conversion of about 15% of COD to volatile organic acid is utilized.

In aerobic conditions from the effluent flowing into the anaerobic reactor, the phosphorus-removing microorganism absorbs some of the organic matter in the water and decomposes PHB stored in the cell to obtain a carbon source necessary for cell synthesis.

The energy required is obtained by synthesizing ATP in the TCA circuit, and phosphorus in the water is absorbed into the cells of phosphorus-removing microorganisms and is excessively ingested in the form of polyphosphate, and a part of the ingested microorganisms is surplus in the process. By discharging to the sludge, phosphorus removal is achieved.

However, the presence of other electron acceptors other than oxygen, i.e., nitrates, during the release of phosphorus will interfere with phosphorus release, resulting in poor treatment efficiency.

In addition, the principle of nitrogen removal is that nitrogen in biological treatment is partially removed by assimilation of microorganisms, and further nitrogen removal requires a continuous nitrification-denitrification reaction which is removed by nitrogen gas through nitrification and denitrification. .

Usually, the reduced form of nitrate dissolved in sewage occurs in two forms.

That is, it is divided into microorganism assimilation and general well-known catabolism, which is related to reduction to ammonia to be used for cell synthesis and occurs independently with or without dissolved oxygen, and catabolism is denitrification. In the reaction, organic or inorganic materials are reduced to nitrogen oxides by electron donors. It is a method of converting into nitrogen gas (N ₂ ) and diffusing it into the atmosphere by a specific microbial action.

Nitrification refers to a process in which ammonia nitrogen is converted to nitrate nitrogen through a nitrite group by nitrification bacteria, and the process of nitrification is shown in Scheme 1 below.

2NH ₄ + 3O ₂ + 4HCO ₃ → 2NO ₂ + 4H ₂ CO ₃ + 2H ₂ O ( Nitrosomonas )

2NO ₂ + O ₂ → 2NO ₃ ( Nitrobacter )

During nitrification, alkalinity consumes 7.14 mg / mg of ammonia and 4.47 mg of dissolved oxygen. Dissolved oxygen concentration to induce nitrification is more than 2mg / ℓ, the optimal pH is 8.4 ~ 9.0, nitrification is inhibited below pH 6.

Denitrification is a process of reducing nitric acid or nitrite produced by nitrification to nitrogen gas by a microorganism using an electron acceptor as in Scheme 2 below.

_{- 3NO 3 + CH 3 OH →} 3NO 2 + 2H 2 O + H 2 CO 2 ( Pseudomonas (Pseudomonas))

2NO ₂ + CH ₃ OH + H ₂ CO ₃ → N ₂ + 3HCO ₃ + H ₂ O

As shown in Scheme 2, the denitrification process requires organic matter as a hydrogen donor as a nutrient source of microorganisms.

On the other hand, as shown in Figures 1a to 1d, the conventional biological treatment process, for example, A ₂ / O process (see Fig. 1a), which is appropriately mixed and treated simultaneously with the principle of elimination of nitrogen and phosphorus (nutrient salts), Modified Badenpo process (see FIG. 1B), UCT process (see FIG. 1C) and VIP process (see FIG. 1D).

The A ₂ / O step is a step of adding an anoxic tank between an anaerobic tank and an aerobic tank to an existing A / O process to simultaneously remove nitrogen oxides and phosphorus.

Referring to Figure 1a, it is possible to reduce the nitrogen oxide content of the conveying sludge to reduce the influence of nitrogen oxide in the dephosphorization process. The circulation from the aerobic tank to the denitrification tank usually amounts to 100-300% of the influent, and the phosphorus removal rate is lower than that of the A / O process, but it can remove 40-70% of nitrogen.

The modified Badenpho process is designed to increase the efficiency of nitrogen removal at low organic loads, and is a process that makes it possible to remove phosphorus by adding an anaerobic tank to the existing Badenpo process.

Referring to Figure 1b, the influent and the return sludge is mixed, the fermentation reaction and the release of phosphorus proceeds in the anaerobic tank, 70% nitrogen oxides generated in the process in the first denitrification tank with the mixed liquid returned from the inside is soluble BOD Are removed together.

Then, BOD, ammonia and phosphorus are removed in the aerobic tank, and denitrification reaction takes place using the carbon source generated by decomposition of microorganisms in the second denitrification tank. The second aerobic tank prevents the release of phosphorus from the anaerobic microorganisms in the settling tank.

The UCT (University of Cape Town) process is a process made by modifying the Badenpo process. Referring to FIG. 1C, since the returned sludge is introduced into the denitrification tank instead of the anaerobic tank, the phosphorus is released from the anaerobic tank. It can reduce the effect of nitrogen oxides on.

Nitrogen oxides in anaerobic baths reduce phosphorus release from dephosphorus bacteria because they compete with each other for BOD, the carbon source, between denitrifiers and dephosphorus bacteria. The return of the mixture from the denitrification tank to the anaerobic bath is to supplement the BOD of the anaerobic bath, but there is a possibility that nitrogen oxides may flow into the anaerobic bath when the mixture is returned from the aerobic bath to the denitrification bath.

To compensate for this, the modified UCT process was designed to have two denitrification tanks, with the first tank reducing nitrogen oxides in the return sludge and the second tank receiving the mixture from the aerobic bath to increase the nitrogen removal throughout the process.

VIP (Virginia lnitiative Plant) process is similar to the UCT process, but was developed for a high rate of operation. Referring to FIG. 1D, the operating days (SRT) is short, 5 to 10 days, and the operation is performed by increasing the amount of active biomass, thereby increasing the phosphorus removal efficiency and reducing the reactor capacity. Leave.

In addition, it was designed to connect two or more complete mixing tanks in series to anaerobic, anoxic and aerobic reactors to apply the plug-flow characteristics of the reactor.

Therefore, the remaining amount of organic matter in the first reaction tank in the complete mixing tank of aerobic conditions is increased process to increase the phosphorus removal efficiency.

However, in the conventional high-treatment process as described above, when applied to existing treatment plants and new facilities for sewage and wastewater treatment, the characteristics and seasonal conditions of domestic sewage do not fit the situation in Korea.

This is because domestic influent sewage has lower concentration of organic matter and higher concentration of nitrogen than other countries, so it is inferior in treatment efficiency, and due to seasonal effects, temperature is high in summer and sludge rises in sedimentation tank and low temperature in winter. This decreases the processing efficiency.

In addition, the applied foreign construction method requires a long residence time, which requires additional capacity expansion at existing facilities, and therefore requires high economic cost.

In the prior art, Korean Patent No. 165630, in a sewage treatment apparatus for treating nitrogen and phosphorus in sewage, a plurality of anaerobic tanks, a number of anaerobic tanks, a plurality of aeration tanks are sequentially combined to be interlocked through the water gate; An underwater mixer installed inside and below the plurality of anaerobic tanks and the plurality of anaerobic tanks; An inflow water device installed in the second anaerobic tank and the primary sedimentation branch; An internal conveying apparatus installed under the fourth aeration tank and connected to the first anaerobic tank; A blower connected to an air diffuser installed inside and below the plurality of aeration tanks; A settling tank which is interlocked through the sluice of the fourth aeration tank and interlocked through the sluice of the fourth aeration tank of the treatment tank; It is known to provide a sewage nitrogen and phosphorus advanced treatment apparatus composed of a sludge conveying apparatus connected to a lower portion of the settling tank and installed between the second anaerobic tank.

In addition, the Republic of Korea Patent No. 254843 collects the sewage introduced from the outside and agitates with a stirring blade, a coagulation tank receiving coagulant from the chemical tank to coagulate the sewage, and a coagulation aid is supplied from the chemical tank after coagulation. A first treatment part comprising a coagulation tank for condensation under stirring, a primary sedimentation tank for precipitating dewatered COD removed through the coagulation tank, and a sludge obtained by precipitating sewage from which COD has been removed from the primary treatment part. Fermentation tank supplied and fermented to BOD, Concentration separation tank for achieving proper BOD in this fermentation tank to concentrate and separate volatile organic acid organic matter into sludge and organic acid, and organic acid storing sludge removed and remaining organic acid A secondary processing unit composed of a storage tank; After passing through the primary treatment unit, a primary denitrification tank, a primary nitric acid tank, a secondary denitrification tank, and a secondary nitric acid tank, which are arranged to remove nitrogen in the sewage, are alternately arranged, and configured as a tertiary treatment unit for denitrification and nitrification. It is known to disclose a system and method for simultaneously removing nitrogen and phosphorus in sewage.

In addition, Korean Patent Application No. 98-032764 uses an adjusting tank for adjusting the quantity, water quality and temperature of organic wastewater, and a sedimentation tank for settling aeration tank and sludge in the wastewater adjusted in the adjustment tank. In the method for treating organic wastewater while returning the control tank and the aeration tank, the aeration tank and the aeration tank are repeated by performing intermittent and repeated aeration of the aeration tank and the aeration tank alternately. In order to remove and denitrify and dephosphate organic matter, and to treat the treated water denitrified in the control tank in the aeration tank, dephosphorization in the aeration tank is actively carried out, thereby eliminating the need for additional tertiary treatment facilities. Of course, organic materials that can remove phosphorus and nitrogen It is known to disclose a method for removing organic matter, phosphorus and nitrogen from wastewater, and a device thereof.

In addition, Korean Patent Application No. 2000-020730 discloses the denitrification and phosphorus release reactions of nitrogen and phosphorus in sewage and wastewater under anaerobic and anaerobic conditions, and organic matter and nutrients in a sequencing batch reactor (SBR). It is known to disclose a method for removing nitrogen and phosphorus from sewage and wastewater and its apparatus which are subjected to ash treatment by continuous inflow and intermittent discharge.

However, the methods mentioned in the above patents have a problem that the facility, the apparatus and the process are complicated, and the processing efficiency thereof is low. In addition, the above methods may be suitable for treating a small amount of wastewater, but there is a problem that cannot be applied to a large amount of wastewater treatment.

Accordingly, the present invention has been made to solve the above problems, in accordance with the domestic situation, in the state of low organic matter load or attached to the front end anaerobic tank in the reaction tank floating / adhesion to respond to seasonal temperature changes properly in the anaerobic / It was completed on the basis of repeating the exhalation to simplify the whole process and reduce the maintenance cost.

That is, in the present invention, the anaerobic, aerobic activated sludge method and the biofilm method were properly combined, and a system for treating higher anaerobic, anaerobic, and aerobic conditions in a reactor filled with filter media was repeatedly developed several times.

Accordingly, an object of the present invention is to provide a method for efficiently removing organic matter, nitrogen and phosphorus from sewage and wastewater.

Another object of the present invention is to provide an apparatus to which the method can be applied.

Method for removing nitrogen and phosphorus from sewage and wastewater of the present invention for achieving the above object is the screening step of immersing and filtering the solids of the incoming wastewater; A contact anaerobic step of relieving the flow load of the screened wastewater and carrying out phosphorus elution and organic matter removal in an anaerobic state; A first step of contact periodic aeration in which the contact anaerobic wastewater is removed when abandoning phosphorus and organics discharged through periodic aeration / aeration, and a denitrification reaction takes place using an inflowed organic material during aeration; A second contact periodic aeration step in which nitrification and denitrification occur through the periodic aeration / non-aeration of the wastewater that has passed the first contact periodic aeration step; Contact continuous aeration step of performing nitrification with the remaining organic matter through the continuous aeration of the wastewater passed through the second contact periodic aeration step; In the continuous contacting step of aeration, the sludges grown while decomposing nitrogen and phosphorus are sedimented, and the supernatant is sent to the next process, and the treated water containing a small amount of sludge is returned to two contact periodic aeration tanks as necessary, and the excess sludge is stored in the sludge storage tank. Final precipitation step of transferring to the furnace; Disinfection discharging step of disinfecting the final precipitated treated wastewater before discharge; The sludge storage step of storing the resulting excess sludge and returning the supernatant to two contact periodic aeration tanks.

Nitrogen and phosphorus removal device from the sewage and wastewater of the present invention for achieving the above another object is a sedimentation and screen bath to filter out the solids such as sand or contaminants contained in the wastewater; A contact anaerobic tank for mitigating the flow load of the influent water filtered by the sedimentation and screen tanks and performing organic matter removal and phosphorus elution; It consists of one contact periodic aeration tank and two contact periodic aeration tanks that periodically give up and aeration, and a continuous contact aeration tank to give up continuously to treat organic matter, nitrogen, and phosphorus in the influent introduced by the contact anaerobic tank. Contact periodic / continuous aeration tank to repeat aeration; A final settling tank for solid-liquid separation of the treated water flowing out by treatment in the contact periodic / continuous aeration tank; Disinfection discharge tank for disinfecting / discharge of the treated water discharged from the final sedimentation tank; And a sludge storage tank capable of treating excess sludge produced in the final settling tank.

1a to 1d is a biological process flow chart according to the prior art,

Figure 1a is a conventional A ₂ / O process diagram,

Figure 1b is a conventional modified Badenpho process (Bandenpho) process,

Figure 1c is a conventional process of the University of Cape Town (UCT),

Figure 1d is a conventional VIP (Virginia Initiative Plant) process diagram,

2 is a process diagram of a high-order treatment system by a floating / attached reactor and a periodic aeration method according to the present invention;

3 is a system diagram of a high-order treatment system by a floating / attached reactor and a periodic aeration method according to the present invention;

4 is a schematic block diagram of a high-order treatment system using a floating / attached reactor and a periodic aeration method according to the present invention.

<Description of Symbols for Main Parts of Drawings>

1a: screen 1b: PVC pipe piping

1c: Monthly wear 1d: Center wall

1e: Submersible pump 1f: Aeration device

1 g: rectification plate 2a: anaerobic media

2b: PVC pipe piping 2c: Transfer line (STS pipe)

3a: Contact periodic aeration tank media 10: Sedimentation and screen bath

20: Contact anaerobic tank 30: Contact periodic / continuous aeration tank

31: 1 contact periodic aeration tank 1 32: 2 contact periodic aeration tank

33: Contact continuous aeration tank 40: Final sedimentation tank

50: sterilization discharge tank 60: sludge storage tank

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

Figure 2 is a process diagram schematically showing a high-order treatment system according to the floating / attached reaction tank and the periodic aeration method of the present invention, Figure 3 is a schematic diagram of a high-order treatment system by the floating / attached reaction tank and the periodic aeration method of the present invention. 4 is a schematic block diagram showing a high-order treatment system by a floating / attached reactor and a periodic aeration method of the present invention.

Referring to Figures 2 and 3, the apparatus of the present invention includes a sedimentation and screen bath 10 to filter out solids such as sand or contaminants contained in the influent; A contact anaerobic tank (20) for mitigating the flow load of the inflow water filtered by the sedimentation and screen tank (10) and performing organic material removal and phosphorus elution; A contact periodic / continuous aeration tank 30 which repeats periodic aeration to process organic matter, nitrogen, phosphorus of the influent water introduced by the contact anaerobic tank 20; A final settling tank 40 for solid-liquid separation of the treated water flowing out by treatment in the contact periodic / continuous aeration tank 30; Sludge storage tank 60 is composed of a disinfection discharge tank 50 for disinfecting / discharging the treated water discharged from the final sedimentation tank 40, and also can process the excess sludge generated in the final sedimentation tank (40) Is installed.

The contact periodic / continuous aeration tank 30 is a contact continuous aeration tank 33 which continuously gives up with one contact periodic aeration tank 31 and two contact periodic aeration tanks 32 which periodically repeat aeration / aeration. Consists of.

At this time, the one contact periodic aeration tank 31 and the two contact periodic aeration tank 32 give up 0.5 to 2 / 0.5 to 2 hours in a cycle of 1 to 4 hours depending on the characteristics of the inflow load. It is carried out at the ratio of.

It maintains both aerobic and anoxic conditions at appropriate conditions, firstly inducing nitrification in the aerobic state, inducing denitrification in the anaerobic state, and secondly removing phosphorus released from the shear contact anaerobic tank in the aerobic state. And third, organic matter can be removed in an aerobic state.

Further, in order to completely treat the untreated sewage in the reaction, continuous aeration for 4 to 9 hours is performed in the contact continuous aeration tank 33.

On the other hand, in the final sedimentation tank 40, the internal conveyance to the contact periodic / continuous aeration tank 30 is made, it is disposed in the sludge storage tank 60 for the excess sludge treatment.

In addition, the method of the present invention, with reference to Figure 4, the screening step (ST 100) to settle and filter the incoming solids; A contact anaerobic step (ST 200) for mitigating the flow load of the raw water filtered in the screening step (ST 100) and performing phosphorus release and organic matter removal in an anaerobic state; A contact periodic aeration step (ST 310) in which the phosphorus and untreated organic matter discharged from the contact anaerobic step (ST 200) are removed at the time of aeration and denitrification occurs using the introduced organic material at the time of aeration; A second periodic contact point aeration step ST 320 in which nitrification and denitrification occur through periodic aeration / non-aeration of the sewage flowing out of the first periodic contact point aeration step ST 310; Contact continuous aeration step of performing nitrification with the residual organic matter through the continuous aeration (ST 330); In this step, the sludge grown while decomposing nitrogen and phosphorus is precipitated, and the supernatant is sent to the next process, and the treated water containing a small amount of sludge is returned to the contact periodic aeration tank 2 chamber 32 as necessary, and the excess sludge is sludge. A final precipitation step (ST 400) for transferring to the storage tank (60); A disinfection discharge step (ST 500) capable of performing disinfection before discharge of the treated water in the final precipitation step (ST 400); The generated sludge is stored, and the supernatant water includes a sludge storage step ST 600 which is returned to the two contact periodic aeration tanks 32.

According to the present invention, the sedimentation and screen tank 10 is a pretreatment step of the wastewater, in which sand and large and small types of contaminants in the influent are mixed. In order to protect the machinery of the subsequent process, the material having a high specific gravity is settled and the medium and large solids. Is a pretreatment process to remove the filter.

In addition, the contact anaerobic tank 20 controls the fluctuation of the flow rate of the influent sewage to control the constant fluctuation or less, precipitates the solid matter contained in the sewage, decomposes and oxidizes the fibrous components, thereby lowering the BOD load, and the subsequent process occurs due to phosphorus elution. To increase the processing efficiency.

The organic matter of the sewage introduced into the contact anaerobic tank 20 begins to decompose at the same time as the inflow. Dissolved organics are stored in cells of assimilation and catabolism by microorganisms and phosphorus-removing microorganisms, and many of them are removed.

Under anaerobic conditions in which dissolved oxygen does not exist in water, organic matter in sewage is stored in the form of Poly-Hydroxyl Butylate (PHB) in the phosphorus-removing microorganism. In order to minimize the effects of nitrates, contact anaerobic tanks were placed at the front end to reduce the function of phosphorus elution, and the concentration could be maintained two to three times higher than the concentration of phosphorus in the influent.

In addition, in order to increase the denitrification efficiency of the next step, it is composed of a structure of the PVC pipe pipe (1b) that can be divided into a contact periodic aeration tank to inject sewage, the flow rate ratio is 1: 3 times (Q).

The inside of the contact anaerobic tank 20 is filled with more than 55% by volume of the anaerobic filter media (2a) fixed by the support and the net, the sewage flowing from the screen tank has a structure that is treated in an upflow manner. The anaerobic medium is capable of growing anaerobic microorganisms, preferably a fixed bed medium having a relatively high porosity in which polyethylene or waste plastic is foamed.

In addition, the contact periodic / continuous aeration tank 30 is composed of one contact periodic aeration tank 31, two contact periodic aeration tank 32 and the contact continuous aeration tank 33. At this time, the operation sequence is one cycle of the periodic contact aeration tank 31 and two chambers of the periodic contact aeration tank 32 give up and abandon 0.5 to 2 / 0.5 to 2 hours at a cycle of 1 to 4 hours depending on the characteristics of the inflow load. The ratio is 1: 1.

This repetitive operation is performed 2 to 24 cycles, 3hr to 1day, depending on the type of inflow sewage and sewage, operation state, and load variation. In addition, in order to completely treat the untreated sewage in the reaction, a continuous aeration is made in the contact continuous aeration tank 33.

The contact periodic / continuous aeration tank 30 has a structure filled with more than 55% by volume of the contact periodic aeration tank filter 3a fixed by a support and a net, and the inflow of sewage is a structure that can be treated in an upflow manner. It is composed of an aeration device (1f) that can be.

The aeration tank media can be grown in breathable microorganisms, it is preferable that the fixed bed media having a relatively high porosity foamed polyethylene or waste plastic.

One cycle of the contact periodic aeration tank 31 removes organic matter and phosphorus due to carbon oxidation reaction and dephosphorization reaction under aeration conditions, and denitrification reaction occurs through the organic carbon source introduced at the previous stage during aeration.

That is, the main function of one contact periodic aeration tank 31 is to remove organic matter and phosphorus in aerobic state, and to denitrify in anoxic state.

The contact periodic aeration tank 2 chamber 32 is nitrified under aeration conditions and denitrification occurs under aerobic conditions. That is, denitrification occurs in anoxic state, and nitrification occurs in aerobic state.

In addition, PVC pipe piping (1b) for injecting sewage from the contact anaerobic tank (20) for supplying the organic carbon source and PVC pipe piping (2b) for injecting supernatant from the sludge storage tank (60) are necessary. In order to prevent the deterioration of nitrogen removal efficiency in the starting system, a conveying line 2c is formed.

The present invention is supplied as a BOD organic material in itself without addition of other specific organics (generally methanol), thereby achieving a double effect of denitrification and BOD removal.

In the continuous aeration tank 33, untreated organic matter, phosphorus removal occurs, and complete nitrification occurs.

The apparatus according to the present invention is a natural flow type, the supernatant is moved, and the pipe (20 to 40% by weight) for sending the waste water from the contact anaerobic tank 20 to the contact periodic aeration tank 32.

As described above, the attached growth system of the present invention can grow microorganisms regardless of residence time of sewage and wastewater, and can safely grow bacteria with low growth rate such as nitrification bacteria. In the aerobic state, the oxygen transfer rate is 2.5 times higher than the suspended growth equation.

For this reason, the variety of species increases, especially the share of the animal components compared to other methods, the presence of micro-subspecies remarkably large, the food chain is long and complicated, which increases the ability to respond to changes in environmental conditions.

In addition, as the number of living organisms at higher levels of nutrition increases, the sludge age becomes longer and the rate of loss to energy increases, resulting in less sludge generation due to the promotion of self-oxidation of the sludge.

In addition, by forming a variety of microconsortia ( microconsortia ), it is resistant to fluctuations in quantity, water quality, water temperature, etc., and is excellent in solid-liquid separation.It is attached to the media even when filamentous microorganisms proliferate considerably. The problem can be reduced.

In addition, the final settling tank 40 is the treated water containing a small amount of sludge after flowing the supernatant passed through the contact anaerobic tank 20, the contact periodic / continuous aeration tank 30 in the tangential direction in the center wall (1d) It is returned to the contact periodic aeration tank 2 chamber 32 as needed, the excess sludge is stored in the sludge storage tank 60, and taken out, and the supernatant is sent to the next process through the overflow weir (1c). In the final precipitation step (ST 400), the internal conveyance is 80 to 90% by weight to the contact periodic aeration step (ST 320), and 10 to 20% by weight to the sludge storage step (ST 600).

The process consists of a submersible pump 1e and a conveying line 2c for internal conveying. The method of the present invention has a stronger internal conveying concept than a sludge conveying concept because the amount of sludge generated as mentioned above is considerably small.

Therefore, the summer and winter seasons are divided into 4 to 8% by weight of internal transport for equalization in the reaction tank in summer, and 10 to 15% by weight of internal transport is carried out because denitrification is low due to temperature decrease. Let. This is to prevent the reduction of the denitrification efficiency during the winter season by reducing the concentration of nitrate nitrogen flowing in.

In addition, the supernatant transferred from the disinfection tank 50 sedimentation tank contacts the solid chlorine agent to disinfect Escherichia coli, which is an indicator of pathogenic bacteria, and the sludge storage tank 60 stores and discharges excess sludge. The supernatant water through the overflow weir (1c) is composed of a PVC pipe pipe (2b) that can be sent to the two chambers 32 contact periodic aeration tank. At this time, the supernatant of the sludge storage tank is injected into the contact dropping tank 2 (32) by natural flow.

As described above, the present invention is very different from the conventional inline reactor in that the anaerobic, anaerobic, and aerobic maintenance required for the higher order treatment of wastewater is provided in a temporal concept rather than a spatial concept. The combination of the media and the efficiency of high-order treatments is innovatively differentiated from the existing treatment methods.

In addition, BOD, COD, and SS of the wastewater can be treated as well as nitrogen and phosphorus, and inflow and wastewater treatment is carried out step by step. Rather than purchasing carbon donors to significantly increase the efficiency of wastewater treatment and to promote nitrification and denitrification, volatile organic acids aged in an anaerobic tank can be introduced into two contact periodic aeration tanks to maximize the removal of nitrogen by properly formulating the C / N ratio. .

In addition, and is discharged to the by minimizing the effect of placing a contact anaerobic tank at the front end nitrate and begin to give up while flowing the effluent of the contact anaerobic tank in contact with periodic aeration tank by the bacteria Acinetobacter (Acinetobacter) so that the accumulation over the intake The carbon source is oxidized, nitrified, and aeration is stopped to operate in an oxygen-free state so that denitrification occurs. The system continues to cycle.

Inlet and waste water is accumulated in the anaerobic state is a volatile organic acid bacteria Acinetobacter (Acinetobacter) which is released to phosphate such as acetic acid in the in the rear needle thread passed through the screen, and the crude free-flowing system, contact the anaerobic tank.

On the other hand, the anaerobic tank and the aeration tank of the present invention are filled with contact media, so that it is possible to treat high concentration organic sewage and wastewater compared to activated sludge method or batch reactor (SBR), and the amount of excess sludge generated is 1/4 to 1 / 5 or so.

In addition, the facility is greatly simplified, and thus, the electricity usage fee is greatly reduced, thus reducing the operation and maintenance costs, and the closed structure prevents noise and odors, and does not require a flow control tank, and reduces the efficiency of winter denitrification. In order to prevent the problems caused by temperature drop, the internal conveyance in the final settling tank was used as two contact periodic aeration tanks, and it is composed of a floating / attachment reaction tank of periodic aeration method, which is efficient in terms of initial installation cost and maintenance.

In addition, as described above, the present invention is excellent in solid-liquid separation due to the formation of various microbial species ( Microconsortia ) and is resistant to fluctuations in quantity, water quality, water temperature, and the like, and even though the filamentous microorganism grows considerably, such as activated sludge method. Problems such as swelling and sludge injury can be reduced and the scope of application is diverse.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

Comparative Example 1

The treatment efficiency of organic matter, nitrogen and phosphorus was measured by treating the wastewater having the properties shown in Table 1 by the existing activated sludge method operating in most treatment plants in Korea, and the results are shown in Table 1 below.

Example 1

As the first pretreatment step, sewage with inflow of sewage with BOD 101.7 mg / l, SS 125.3 mg / l, TN 26 mg / l, and TP 4.1 mg / l was treated as a first pretreatment step. And the material having a high specific gravity was settled through the screen tank 10 and the medium and large solids were filtered out.

As a second step, the contact anaerobic tank 20 was operated with a DO: 0.1 mg / l or less, PH 6.5-7.5, HRT 8hr.

As a third step, the contact periodic / continuous aeration tank 30 consists of one contact periodic aeration tank 31, two contact periodic aeration tanks 32, and a continuous contact aeration tank 33, one contact periodic aeration tank 31. , The ratio of aeration / aeration was set to 1: 1 to maintain the aerobic and anaerobic conditions in the reaction tank according to the aeration / aeration time in accordance with the aeration / aeration time. Abandoned / aerated 60/60 minutes to 2 hours.

This repetitive operation was performed 12 cycles / day for 24 hours of HRT. In order to treat untreated sewage and wastewater in the previous stage of treatment, the continuous aeration tank 33 was continuously abandoned with HRT 6hr.

As a fourth step, the final settling tank 40 includes a small amount of sludge after flowing the supernatant passed through the contact anaerobic tank 20 and the contact periodic / continuous aeration tank 30 in the tangential direction from the center wall 1d. The treated water was returned to the two contact periodic aeration tanks 32, and the excess sludge was stored in the sludge storage tank 60 and then taken out.

In this process, it consists of an underwater pump 1e and a conveying line 2c for internal conveyance, and it divided into summer and winter season, and carried out 4-8% in summer and 10-15% in winter based on inflow. In addition, the treated water passed through the final settling tank 40 was discharged through the disinfection discharge tank (50).

As a result, the treatment efficiency of the organic material, nitrogen and phosphorus of the present invention is shown in Table 1 below.

division Comparative Example 1 Example 1 Inflow (mg / ℓ) Emission (mg / ℓ) % Removal Inflow (mg / ℓ) Emission (mg / ℓ) % Removal BOD 100 21 79 101.7 3.5 96.5 SS 114 22 81 125.3 3 97.6 T-N 25 20 20 26 9 65 T-P 3.9 3.4 13 4.1 1.9 53.6

As can be seen from Table 1, the treatment efficiency using the conventional activated sludge method is very low treatment efficiency of 79% for BOD, 81% for SS, 20% for TN, 13% for TP, When treated by the method of the present invention, the treatment efficiency is 99.5% for BOD, 97.6% for SS, 65% for TN, and 53.6% for TP to obtain very stable water quality.

In addition, the amount of excess sludge generated can keep the microorganism retention time as the microorganisms adhere to the media and consume the organic materials in the form of microbial survival energy and growth energy, and the organic matter is removed by the microorganism's assetization. do. That is, in the case of activated sludge method, 8.5Kg / 100m 3, and the present invention has a difference of about 4-5 times or more with 2Kg / 100m 3.

On the other hand, comparing the items related to the operating cost with the activated sludge method is shown in Table 2 below.

driving Activated Sludge Process This method Administrative expenses Resident Management Unmanned operation Drug costs has exist none Electricity 30 ~ 400,000 won / month 8-100,000 won / month Sludge Generation (Daily) 8.5㎏ / 100㎥ 2㎏ / 100㎥

In addition, the operating cost of the present invention is to reduce the power cost by performing periodic abandonment, and to reduce the cost by unmanned operation in the case of activated sludge method on the basis of 100 tons except for the administrative cost, the power cost of only 30 to 400,000 won / month, the present invention is the power Obesity was 100,000 won / month 3 ~ 4 times the effect was reduced.

Claims (7)

Screening to settle and filter solids in the incoming wastewater; A contact anaerobic step of mitigating the flow load of the screened wastewater and performing phosphorus release and organics removal in an anaerobic state; Contact periodic aeration step of removing phosphorus and untreated organic matter released in the contact anaerobic step at the time of aeration and denitrification reaction using the introduced organic material at the time of aeration; A second contact periodic aeration step in which nitrification and denitrification occur through the periodic aeration / non-aeration of the wastewater that has passed the first contact periodic aeration step; Contact continuous aeration step of performing nitrification with the remaining organic matter through the continuous aeration of the wastewater passed through the second contact periodic aeration step; In the aeration stage, the sludge grown by decomposing nitrogen and phosphorus is precipitated, and the supernatant is sent to the next process, and the treated water containing a small amount of sludge is returned to two contact periodic aeration tanks, and the surplus sludge is transferred to the sludge storage tank. ; Disinfection discharging step of disinfecting the final precipitated treated wastewater before discharge; And A method of removing nitrogen and phosphorus from sewage and wastewater, wherein the excess sludge is stored and the supernatant is returned to two contact periodic aeration tanks. The method of claim 1, wherein the first step of contact periodic aeration and the second step of periodic contact abandonment give an aeration / aeration ratio of 1: 1 according to the characteristics of the influent wastewater, and a 1 to 4 hour cycle of 0.5 to 2 / Method for removing nitrogen and phosphorus from sewage and waste water, characterized in that aeration / aeration for 0.5 to 2 hours. The method of claim 1, wherein the internal conveyance in the final settling step is 80 to 90% by weight to the second step of contact periodic aeration, and 10 to 20% by weight to the sludge storage step characterized in that How to get rid of phosphorus. The method of claim 1 or claim 3, wherein the internal conveying is characterized in that the summer and winter seasons are divided into 4 to 8% by weight in the summer and 10 to 15% by weight in the winter season based on the influent water, characterized in that Nitrogen and phosphorus removal from sewage and wastewater. Sedimentation and screening tanks for filtering out solids such as sand or contaminants contained in waste water; A contact anaerobic tank for mitigating the flow load of the inflow water filtered by the sedimentation and screen tanks and performing organic matter removal and phosphorus discharge; It consists of one contact periodic aeration tank and two contact periodic aeration tanks that periodically give up and aeration, and a continuous contact aeration tank to give up continuously to treat organic matter, nitrogen, and phosphorus in the influent introduced by the contact anaerobic tank. Contact periodic / continuous aeration tank to repeat aeration; A final settling tank for solid-liquid separation of the treated water flowing out by treatment in the contact periodic / continuous aeration tank; Disinfection discharge tank for disinfecting / discharge of the treated water discharged from the final sedimentation tank; And Apparatus for removing nitrogen and phosphorus from sewage and wastewater, characterized in that it comprises a sludge storage tank capable of treating excess sludge produced in the final sedimentation tank. The method of claim 5, wherein the contact anaerobic tank is filled with at least 55% by volume of the medium consisting of a support and a network for the growth of anaerobic microorganisms, the contact periodic / continuous aeration tank is composed of a support and a network for the growth of breathable microorganisms Apparatus for removing nitrogen and phosphorus from sewage and wastewater, characterized in that the filter medium is filled at least 55% by volume. The apparatus of claim 5, wherein the supernatant is moved in a natural flow type, and a pipe (20 to 40% by weight) for sending the waste water from the contact anaerobic tank to the contact periodic aeration tank is provided, and the top water of the sludge storage tank is contact aeration tank. A device for removing nitrogen and phosphorus from sewage and wastewater, which is injected into two chambers in a natural flowing manner.