KR100702194B1 - Advanced wastewater treatment system and treatment method using immersion membrane and desulfurization process - Google Patents

Abstract

The present invention relates to an advanced sewage and wastewater treatment apparatus using an immersion membrane and a denitrification process, and more particularly, a screen, a flow adjustment tank, a membrane bio-reactor, and a sulfur denitrification reactor. The present invention relates to an advanced wastewater and wastewater treatment apparatus and method, which are arranged in a compact order. To this end, the screen device 50 for screening the incoming raw water; An immersion membrane reactor (55) having one side connected to the screen device (50); A denitrification reactor (60) connected to one side of the immersion membrane reactor (55); And a chemical tank (70) for injecting alkalinity between the immersion membrane reactor (55) and the denitrification reactor (60).

Denitrification, sewage and wastewater, flocculation, sludge, reaction, treatment, immersion type, membrane, advanced treatment, alkalinity

Description

Advanced wastewater treatment system by a combination of membrane bio-reactor and sulfur denitrification and method

1 is a process diagram of a wastewater treatment apparatus using a conventional denitrification process;

2 is a process chart of an advanced wastewater treatment system using an immersion membrane and a denitrification process according to a first embodiment of the present invention.

3 is a process diagram of an advanced wastewater treatment system using an immersion membrane and a denitrification process according to a second embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: screen,

12: flow adjustment tank,

14; Chemical Reactor,

16: settling tank,

18: water tank,

20: bio filter tank,

22: treatment tank,

24: denitrification tank,

50: screen device,

53 flow rate adjustment tank,

55: immersion membrane reactor (MBR),

60: denitrification tank,

62: reverse overcurrent means,

64: backwashing means,

65 treatment tank,

70: chemical tank.

The present invention relates to an advanced wastewater treatment system using an immersion membrane and a desulfurization process, and more particularly, a screen, a flow adjustment tank, a immersion membrane reactor (Membrane Bio-Reactor) and a sulfur denitrification reactor (Sulfur Denitrification Reactor). The present invention relates to an advanced wastewater and wastewater treatment apparatus and method, which are arranged compactly in the order of the same process.

Recently, water quality standards have been gradually strengthened as measures to improve water quality in public waters, which are rapidly polluted. In order to improve the quality of the final discharge water, the removal of nutrients (nitrogen and phosphorus) as well as organic matter is very important. Nitrogen and phosphorus compounds in water, in particular, are contaminants that can contribute to the loss of water resources, but are also used as nutrients necessary for algae growth, further exacerbating water quality.

Most of the sewage treatment methods applied in Korea are standard activated sludge process which focuses on organic matter removal rather than nutrients. The representative biological treatment process recently introduced as simultaneous nitrogen and phosphorus removal method is MLE (Modified Ludzack- Ettinger), Anaerobic, anaerobic and aerobic tanks are connected in series, such as the A ₂ O, University of Cape Town (UCT) and Virginia Initiative Plant (VIP) processes.

For example, FIG. 1 is a process chart of a wastewater treatment apparatus using a conventional denitrification process. As shown in FIG. 1, the conventional denitrification process removes suspended solids and phosphorus through chemical coagulation in the chemical reaction tank 14, promotes organic matter removal and nitrification in the biofilter bath 20, and sulfur-limestone In a denitrification tank (24) filled at a constant rate, nitrate nitrogen is denitrated by nitrogen gas by an autotrophic microorganism.

Such a conventional denitrification process has no advantage of external carbon source injection and internal transport, filling sulfur and limestone in a denitrification tank at a certain ratio, and easily supplying alkalinity, and using sulfur particles having lower cost than external carbon sources. However, limestone alone does not supply sufficient alkalinity, so additional injection facilities are needed, and the amount of sludge generated due to flocculation and sedimentation at the front end is increased, the amount of chemical use is increased, the treatment process is complicated, and the operation of the flocculation and precipitation process is not good. There is a disadvantage that the clogging of the biofilm may occur.

Therefore, in the conventional methods as described above, the reaction tanks must be installed separately, so that a large area is required, and the aerobic tank capacity must be increased. In addition, due to insufficient maintenance of sewage pipes, the concentration of organic matter is lower than the concentration of organic matter necessary for denitrification. Therefore, nitrogen and phosphorus treatment technologies that are sensitive to organic load are extremely difficult to maximize nitrogen and phosphorus removal efficiency. Therefore, there is an urgent need to develop a breakthrough process that can fully utilize existing facilities while satisfying the strengthened water quality standards.

Accordingly, the present invention has been made to solve the above problems, the first object of the present invention is to promote high organic matter and SS (floating material) removal and high rate of nitrification in the immersion membrane reaction process, chemical aggregation Phosphate is removed by the filtering function of the sulfur filter in the post-desorption denitrification process without sedimentation, and at the same time, immersion type membrane and denitrification to remove nitrogen by sulfur denitrification without internal transport and injection of external carbon source. It is to provide an advanced wastewater treatment system using a process.

The second object of the present invention, in order to remove the phosphorus and nitrogen at the same time in the denitrification process without the injection of the internal transport, the settling basin and the external carbon source in the order of the immersion membrane process and the denitrification process of the stable and excellent treatment water quality Due to the simplification of the treatment process, it is easy to apply from a small packaged facility to a large-scale treatment facility, so it has high advantages such as excellent field applicability and easy operation method. To provide a device.

Other objects, specific advantages and novel features of the invention will become more apparent from the following detailed description and the preferred embodiments described in conjunction with the accompanying drawings.

An object of the present invention as described above, the screen device 50 of 200㎛ mesh for screening the incoming raw water;

An immersion membrane reactor (55) having one side connected to the screen device (50);

A denitrification reactor (60) connected to one side of the immersion membrane reactor (55); And

Chemical tank 70 for injecting alkalinity between the immersion membrane reaction tank 55 and the denitrification reaction tank 60; Can be achieved by

And, in order to equalize the temporal fluctuations in the flow rate and the water quality, it is preferable to further include a flow rate adjustment tank 53 between the screen device 50 and the immersion membrane reaction tank 55.

In addition, it is more preferable that the hollow fiber membrane for solid-liquid separation is immersed in the immersion type membrane reaction tank 55.

In addition, the inside of the immersion membrane reaction tank 55 is more preferably provided with an diffuser for supplying air.

In addition, it is more preferable that the chemical tank 70 further includes a flocculant injection means to remove phosphorus.

In addition, the flocculant injection unit is most preferably further comprises a metering pump for injecting the flocculant constant.

And, the denitrification reaction tank 60 is most preferably further included a backwashing means 64 in parallel with air and water to maintain the activity of the denitrification bacteria in the tank.

In addition, it is most preferable to further include a backwashing means 62 for storing the backwashing overflowed water of the denitrification reactor 60 via the screen 50 in the flow rate adjusting tank 53.

An object of the present invention as described above, as another category of the present invention, the step of screening the incoming raw water through the screen device 50;

Permeating the separator while supplying air through the immersion membrane reactor (55) to nitrify;

Injecting alkalinity and flocculant from the chemical tank (70) to the treated water that has passed through the separator; And

Denitrification step of removing nitrogen by autotrophic denitrification using sulfur in an anoxic condition in the denitrification reactor (60); achieved by the advanced sewage and wastewater treatment method using the immersion membrane and the denitrification process, characterized in that consisting of Can be.

And, the denitrification step, preferably further comprises the step of removing phosphorus through direct filtration.

In addition, the denitrification step, it is preferable to further include a backwashing step in parallel with air and water in order to maintain the activity of the denitrifying bacteria in the tank.

In addition, the denitrification step further includes a backwash phase step of storing the backwash overflow water in the denitrification reaction tank 60 through the screen 50 in the flow rate adjustment tank 53, and the nitrification step includes a continuous air cleaning step and an intermittent step. Most preferably, it includes a formula suction operation step.

In addition, the flocculant may be Alum, and the alkalinity may be Na ₂ CO ₃ or NaHCO ₃ .

The invention will now be described in detail with reference to the accompanying drawings, in which preferred embodiments are shown.

In the present invention, because the immersion membrane is filtered by the immersion membrane in the mixed state with the microorganism in the reactor 55 may exhibit a high organic matter and SS removal rate. In addition, the nitrogen removal of the present invention secures and maintains a large amount of nitrifying microorganisms having a low growth rate in the immersion membrane process to achieve a high nitrification rate (99%), and in the denitrification reactor 60, without the internal transport and injection of an external carbon source. Nitrogen can be removed by high denitrification efficiency. In addition, the phosphorus removal of the present invention is a technique for stably removing the phosphorus by direct filtration in the denitrification process without a precipitation process by injecting a small amount of flocculant into the immersion membrane reactor water of low turbidity less than 1.0 NTU.

Immersion type membrane reaction tank 55 applies a suction filtration type immersion type membrane instead of a settling tank to an existing aeration tank to remove organic matter and complete nitrification. Can produce. In addition, through the continuous air cleaning method and intermittent suction operation to maintain a stable membrane permeate flow rate, the technology to directly clean the chemical solution for the separation membrane installed in the aerobic tank without using a separate cleaning tank was applied.

The denitrification process uses inorganic carbon such as HCO ₃ ^- as a carbon source by Thiobacillus denitrificans , which forms on the surface of sulfur particles without internal transport and supply of external organic carbon sources, and nitrate nitrogen (NO) as an electron acceptor. ₃ ^-- N) while using a denitrification process is less sludge generated, there is an advantage that can be obtained high denitrification efficiency in a short residence time.

Phosphorus removal in the denitrification reactor (60) has a chemical tank (70) between the immersion membrane reactor and the denitrification reactor, injecting a small amount of flocculant into the immersion membrane filtration water of significantly low turbidity (1.0 NTU or less) as a metering pump The mixture is mixed by a line mixer (not shown) installed on the pipe, and the formed micro-flocs are removed by phosphorus (P) through filtration in a denitrification process without precipitation. The impact on denitrification in the denitrification process is minimal. The flocs accumulated in the gaps between the media are discharged to the flow regulating tank 53 by back washing.

Organic and suspended solids removal and nitrification

Immersion type membrane reactor is physically separated from microorganism and treated water through membrane, so sludge bulking and pin-floc frequently occur in sedimentation tank of general activated sludge can be prevented and microorganism concentration can be maintained at high concentration. The treatment water quality is very stable.

Experiments with membrane-bound bioreactors using an intermittent aeration process that removes organics and nitrogen at the same time by controlling aeration in a single reactor indicate that water of very high molecular weight is excluded by the membrane, resulting in prolonged residence time in the reactor. As it decomposes, it insists that it leads to an improvement in treatment efficiency, and even at an organic loading rate of 2 kgBOD / ㎥ · d, the result is much better than the Japanese discharge standard, so that the immersion membrane reactor process has a much larger reaction tank volume than the general activated sludge process. Reported decrease. In addition, the immersion membrane process is operated at a low F / M ratio, and in general urban sewage, the F / M ratio is 0.1 kgBOD / kg MLSS · d so that the microbial growth rate and the killing rate are the same, so that the net growth of the microorganism is not achieved. Therefore, the amount of sludge drawn out can be minimized. In addition, in the case of relatively difficult biodegradable polymer material, the water quality is improved by being prevented by the membrane, and a long solids retention time (SRT) also decomposes and removes a large part of the hardly decomposable polymer material.

The nitrification reaction is oxidized from nitrite nitrogen to nitrate nitrogen using ammonia nitrogen as a substrate. These reactions are carried out by nitrifying microorganisms belonging to the chemical synthesis chemolytho autotrophs. Known as the reaction.

^{_{NH 4 + + 1.5O 2 --->}} NO 2 - + H 2 O + 2H +

^{_{NO 2 - + 0.5O 2 --->}} NO 3 -

Oxidation of ammoniacal nitrogen is mainly carried out by Nitrosomonas , and oxidation of nitrite nitrogen is mainly influenced by Nitrobacter . These nitrifying microorganisms are slower than other microorganisms and have a low rate of production of cells per oxidative energy substrate. The theory of cell production is as follows.

^{_{NH 4 + + 1.83 O 2 +}} 1.98 HCO 3 -

_{---> 0.021 C 5 H 7 NO} 2 + 0.04 H 2 O + 0.98 NO 3 - + 1.88 H 2 CO 3

In general, the growth coefficient of Nitrosomonas is 0.05 ~ 0.29 mgVSS / mgNH ₄ ⁺ -N, and the growth coefficient of Nitrobacter is 0.02 ~ 0.08 mgVSS / mgNO ₂ ^-- N. In addition, the specific growth rate of Nitrobacter is higher than that of Nitrosomonas , so when Nitrite (NO2-N) is produced, it is converted to Nitrate (NO ₃ -N). Therefore, the growth rate of Nitrosomonas dominates the overall nitrification reaction. Nitrifying microorganisms have a slower growth rate than organic matter removing microorganisms (0.5 to 0.7 mgTSS / mgBOD ₅ ), so long SRTs are required for efficient nitrification. In addition, it is reported that the autotrophic bacteria such as nitrifying bacteria having low microbial growth coefficient can be maintained in a large amount and thus are very efficient for the nitrification process.

Energy generated by nitrification reaction is the nitrification microorganisms CO _2, HCO ₃ ^- is used as the alkalinity consumption, such as, CO ₃ ^2- synthetic organic material they need. As a result of urban sewage treatment, 6 ~ 10 mg / ℓ alkalinity was consumed as nitrification of 1 mg / ℓ ammonia nitrogen at pH 7.5 ~ 8.0.

In addition, in the case of the separator used in the immersion membrane process, E. coli and pathogenic bacteria can be completely excluded depending on the pore size of the membrane, so no separate sterilization process is required for the effluent.

Sulfur denitrification

In the denitrification process of the present invention, unlike the existing high-treatment processes, the denitrification process does not require an external carbon source regardless of the C / N ratio, and has a wide range of applications due to less sludge generation. Sulfur is rich in resources, low cost, easy to store, easy to handle and insoluble in water. Sulfur denitrification are autotrophic denitrifying bacteria are used as the inorganic sulfur and carbon, such as Thiobacillus denitrificans in oxygen-free ^conditions for denitrification, using a nitrate nitrogen (NO ₃ -N) the quality (such as HCO ₃₎ as a carbon source, and as a final receptor SO ₄ ^2- is produced as the final product of the sulfur denitrification.

1.06 NO ₃ ^- + 1.11 + S 0.3 0.485 HCO ₃ + H ₂ O

---> 0.5 N ₂ + 1.11 SO ₄ ^2- + 0.86 H ⁺ + 0.06 C ₅ H ₇ O ₂ N

Due to the denitrification in the autotrophic state, the amount of alkalinity is generally consumed by 3-4 mg CaCO 3 / mgNO ₃ -N (4.57 mg CaCO ₃ / mg NO ₃ -N in Formula 4). And 7.54 mg of SO ₄ ^2- is generated to remove 1 mg NO ₃ -N, and 1.28 mmol hydrogen ion (H ₊ ) is produced. The optimum pH for the growth of thiobacillus denitrificans ranges from 6.8 to 8.2 and the DO concentration should be maintained below 0.3 mg / l.

In general, autotrophic denitrification bacteria have a maximum spectrum denitrification rate of 0.1-0.2 gNO ₃ -N / g VSS · d. However, the denitrification rate using methanol as a substrate for heterotrophic denitrification bacteria was 4.41 gNO ₃ -N / gVSS · d. According to the results of the net culture of independent denitrification bacteria, the denitrification rate was 4.23 gNO ₃ -N / gVSS · d. Appeared. According to the recent results of the denitrification rate of heterotrophic and pylori denitrifying bacteria, it was found that they were 1.4-5.4 mgN / gVSS · hr and 2.9-5.0 mgN / gVSS · hr, respectively.

Phosphorus removal process

The present invention is composed of a screen 50, a flow control tank 53, an immersion membrane reactor and a denitrification reactor. In view of the difficulty of simultaneous removal of nitrogen and phosphorus in the existing high-treatment processes for phosphorus removal, the present invention applies a method of removing phosphorus by introducing a micro-floc process of water treatment. This method is applied to the raw water of low turbidity (less than 10 degrees) by directly filtering the coagulant water from the rapid stirring tank, and then performing rapid filtration after directly injecting a small amount of coagulant into the raw water without sedimentation treatment. will be. The formation of flocs occurs mainly in the filter bed, and floc, which is promoted by flocculants, is held in the filter bed and no turbidity leak occurs.

In the present invention, the time point at which the flocculant can be injected is possible at the front end of the immersion membrane process and the front end of the denitrification process, respectively. When the flocculant is injected at the front end of the immersion membrane process, organic matter, suspended solids, and other contaminants other than phosphorus (P) to be removed are generally removed, and sludge generation and chemical costs are increased. This will affect the rate of nitrification in the membrane process. Therefore, if nitrification is hindered in the immersion membrane process, denitrification does not occur as much in the subsequent denitrification process.

For this reason, by placing a chemical tank 70 between the immersion membrane and the denitrification reactor, a coagulant is constantly injected by a metering pump (not shown) to a line mixer (not shown) installed on the outlet pipe of the immersion membrane reactor process. Is mixed by. The formed micro-flocs pass through the medial layer of the denitrification reactor without the precipitation process and the phosphors are removed as the micro-flocs are held between the pores. The impact on denitrification in the denitrification process is minimal. The flocs accumulated in the gaps between the media are discharged to the flow regulating tank 53 by back washing. In addition, suspending by micro-floc does not occur if operating at the proper filtration rate in the denitrification process. In addition, since the immersion membrane filtration water is significantly low turbidity (1.0 NTU or less), a small amount of flocculant is required because most of the flocculant reacts with phosphorus.

Screen (50)

Screen 50 of the present invention is installed on the inner surface of the drum 200㎛ mesh detachably installed, while the drum is rotated, the debris is pushed to the opposite side of the inlet by the rotation of the cylindrical discharge plate, discharged and the treated filtrate is flow adjustment tank 53 Flows into. At this time, the mesh screen is washed once / week.

Infiltration of sewage flowing directly from the raw water reservoir without going through the primary sedimentation basin with a 200 μm mesh inflow of fibrous suspended solids and vinyl fragments, twigs, leaves, sand, etc., which can entangle the hollow fiber membranes in the aerobic tank. Blocking is the main purpose.

Flow Adjustment Tank (53)

The flow rate adjustment tank 53 of the present invention is to improve the treatment efficiency of the treatment facility by absorbing and equalizing the temporal fluctuations in the flow rate of the inflow sewage and the water quality. Through the screen 50, backwashing overflow water of the denitrification reactor process is stored in the flow rate adjustment tank and mixes with the raw water to serve as an immersion membrane process.

Then, the flow rate adjustment ratio of the flow rate adjustment tank is 1.3 to 1.5, and the design sewage amount is the maximum daily sewage amount.

Immersion type membrane reactor (55)

The immersion type membrane reaction tank 55 of the present invention is provided with an immersion type membrane in which the diffuser is integrated. Hollow Fiber Membrane for solid-liquid separation is submerged, and the submerged membrane does not have a separate housing, and requires less volume than the membrane filling area (for example, about 20 to 30% of the aerobic tank volume).

Then, a certain amount (0.5 m 3 / min) of air is supplied to the immersion membrane reactor 55 through an acid pipe to induce smooth organic matter removal and nitrification under aerobic conditions.

The diffuser is integrally installed at the bottom of the membrane frame to prevent sludge deposition and membrane entanglement occurring on the surface of the membrane by the formation of water flow by air. In addition, since a high concentration of microorganisms can be maintained and most organic matter is removed, the volume of the aerobic tank is relatively smaller than that of a general biological treatment.

And it has a high efficiency solid-liquid separation function irrespective of sludge sedimentation.

In addition, about 24 hollow fiber membrane modules are mounted on one frame, and an air diffuser is located below the frame to control sludge deposition on the membrane surface by air and water flow. As a result, the filtration water of the immersion membrane reactor 55 has a significantly low turbidity (1 NTU or less), and even a small amount of flocculant to remove phosphorus can stably remove phosphorus through filtration in a denitrification reactor process without precipitation. .

In addition, the suction pump operating time is preferably operated by dividing the aspirator and the resting machine at regular time intervals in order to extend the life of the separator and improve performance. The operation of the suction pump is primarily controlled by a timer, and secondary control is performed by a water level sensor (not shown) installed in the immersion membrane reactor 55 in case of an emergency.

At this time, the primary control by the timer repeats the operation of the 12-minute operation and the 3-minute rest, and the secondary control by the water level sensor stops operating when the raw water inflow pump (not shown) reaches the upper contact point of the water level. When the contact point is reached, the suction pump (not shown) is stopped and the raw water inflow pump (not shown) is started.

Membrane Cleaning

The cleaning of the separation membrane of the present invention is carried out to prevent the extension of the life of the membrane and the decrease in efficiency. Membrane drug cleaning cycle is basically carried out once every four months, depending on the rapid rise of the differential pressure or the condition of the membrane. The washing method uses sodium hypochlorite (NaOCl). The concentration of NaOCl is 3,000 mg / ℓ solution and it is based on the input of 2 L of chemical amount per ㎡ of membrane.

The cleaning chemical tank is installed at the top of the immersion membrane reactor to perform non-powered chemical cleaning by the natural flow method.

Chemical Tank (70)

In case of lack of alkalinity in the denitrification process, the ability to remove nitrogen decreases, so it is provided between the immersion membrane reactor and the denitrification process to supply alkalinity, and to remove phosphorus by chemical flocculation. This is to install a flocculant injection facility (that is, the chemical tank 70).

Then, Na ₂ CO ₃ or NaHCO ₃ is administered to supply alkalinity for denitrification.

In addition, a flocculant is added to remove phosphorus, a predetermined amount is supplied to a metering pump (not shown), and a line mixer (not shown) is installed on the pipe for mixing. The coagulant may be a polyacrylamide series, which is one of the anionic polymer coagulants, as the inorganic coagulant or the polymer coagulant, and may be used as an alum.

Line Mixer (not shown)

In order to increase the coagulation efficiency of the immersion membrane filtration water, a 20φ × 300L line mixer is installed in the immersion membrane filtration water line.

Denitrification Reactor (60)

The denitrification reactor (or denitrification tank) process of the present invention is a process of reducing nitrogen to nitrogen or nitrogen oxides by autotrophic denitrification using sulfur in anoxic conditions, and flying to the air to finally remove nitrogen.

It is difficult to secure proper C / N ratio for denitrification because of low organic matter concentration and relatively high nitrogen content, and considering the characteristics of domestic sewage with low phosphorus concentration, it has a wide range of application regardless of C / N ratio. Mainly remove nitrogen and phosphorus. Treatment water inflow of the immersion membrane reactor is to install a rectifying plate (not shown) on the inlet of the denitrification reactor to ensure an even distribution of the influent.

Backwashing of the denitrification process 64 is carried out daily in parallel with air and water to maintain the activity of the denitrifying bacteria in the bath. The backwash water 64 of the denitrification process transfers the drum screen to treat the backwash sludge and the raw water together with the immersion membrane process.

Sludge drawing

The sludge disposal in the immersion membrane reactor is adjusted in consideration of the MLSS concentration, and the waste volume is determined within the range in which the appropriate MLSS concentration (4,000 to 7,000 mg / l) is maintained in consideration of the target water quality, especially phosphorus and SRT.

[Table 1] is as follows when the treated water using the above configuration and method is compared with the legal discharged water quality standards (special measures area, other areas).

BOD (mg / ℓ) COD (mg / l) SS (mg / ℓ) T-N (mg / l) T-P (mg / ℓ) Remarks Special Measures Area below 10 40 or less below 10 20 or less 2 or less Other Area 20 or less 40 or less 20 or less 60 or less 8 or less Invention 2.6 to 5.6 5.9 to 10.2 3.6 to 6.8 1.0 to 8.0 0.5 to 1.4 51 spot analysis

As can be seen from the above [Table 1], it can be seen that the treated water according to the present application greatly falls below the standard value regardless of the special countermeasure region or other regions. This indicates that the treatment is not only very effective but also environmentally friendly by the present invention.

Therefore, according to one embodiment of the present invention as described above, unlike the existing advanced treatment technology, there is an advantage that the operation is simple and can simplify the treatment process without sludge conveyance, internal conveyance and sedimentation basin.

More specifically, the nitrogen removal of the present application secures and maintains a large amount of nitrifying microorganisms with low growth rate in the immersion membrane process to achieve high nitrification rate, and in the denitrification process regardless of the C / N ratio, injection of internal transport and external carbon source Since it removes nitrogen by performing denitrification under anoxic conditions, it is possible to reduce power and chemical costs.

Phosphorus removal of the present invention can be stably removed by direct filtration in the denitrification reactor without a precipitation process by injecting a small amount of flocculant into the immersion membrane filtration water of 1.0 NTU or less turbidity.

The immersion membrane treated water of the present invention has an advantage in that organic matter and suspended solids are almost removed and most flocculant reacts with phosphorus with a significantly low turbidity (below 1 NTU), so that a small amount of flocculant is required.

In particular, the present invention may be limited in permeate flow rate due to the solid-liquid separation characteristics of the membrane, but the quality of the treated water quality can be maintained at all times stable and can be satisfied within the legal effluent water quality standards.

In addition, the existing biological nitrogen removal process has a significant effect on nitrification and denitrification efficiency according to the C / N ratio of the influent sewage, so the average C / N ratio should be maintained above 4, but this process is a process using independent nutrient microorganisms. Regardless of the C / N ratio adjustment, it is possible to maintain the average nitrogen removal efficiency around 90%.

Organic decomposition and nitrification (immersion membrane process), denitrification process (sulfur denitrification process) used in the present invention can be arranged in order to maintain a relatively stable treatment efficiency even in the winter / summer water temperature change (inflow water 7 ~ 24 ℃).

In addition, the nitrification (immersion membrane reactor) and the denitrification (sulphurization reactor) are separated to have a high nitrogen removal rate by using the denitrification bacteria in the denitrification process without high nitrification rate and internal transport, precipitation pond and injection of external carbon source.

In addition, in the immersion membrane process, the sludge and the treated water are separated using the immersion hollow fiber membrane of the suction filtration method instead of the solid-liquid separation by the conventional sedimentation basin, thereby achieving high organic matter removal and high-efficiency nitrification.

In addition, most flocs formed by flocculant injection occur mainly in the upper layer of the denitrification reactor, and thus, there is an advantage in that no turbidity leakage occurs.

The present invention consists of an immersion type membrane reaction tank (nitrification) -sulfur denitrification reactor (denitrification) reaction tank rather than the existing sewage treatment, which simplifies the treatment process without sedimentation basin and internal conveyance and processes the total residence time within 5 hours. It is characterized by reducing the required volume of the reactor by more than 15 to 40% compared to the existing advanced treatment method.

The present invention is considerably economical because when the existing treatment plant is converted to an advanced treatment facility with a shorter residence time than the existing standard activated sludge process, a separate site is not required and capacity can be increased.

In particular, the present invention is an immersion membrane process excellent in the removal of organic matter and suspended solids can be applied to heavy water, it is easy to secure an environment-friendly hydrophilic space by preventing secondary pollution by reliably discharged high-quality treated water.

In addition, the sulfur denitrification process with excellent residence time and nitrogen removal rate is easy to be applied to a high nitrogen treatment process such as industrial wastewater and existing sewage treatment facilities. Sulfur is always submerged in the denitrification process, so there is no risk of fire. According to the results of the operation evaluation of this technique, about 7.8 mg of sulphate (SO ₄ ^2- ) is removed as a by-product as 1 mg of nitrate nitrogen is removed. (NO ₃ −: SO ₄ ^{2 −} mole ratio = 1: 1.14). Although there is no effluent water quality standard for sulphate ions (SO ₄ ^2- ), the drinking water quality standard is 200mg / l, and the effect of sulphate discharge from the desulfurization process on the water system is minimal.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it will be readily apparent to those skilled in the art that various other modifications and variations can be made without departing from the spirit and scope of the invention. It is obvious that all modifications fall within the scope of the appended claims.

Claims (16)

A screen device 50 for screening incoming raw water; An immersion type separation reactor 55 connected to one side of the screen device 50; A denitrification reactor 60 having one side connected to the immersion membrane reaction tank 55; A chemical tank 70 for injecting alkalinity between the immersion membrane reactor 55 and the denitrification reactor 60; And A flow rate adjustment tank 53 provided between the screen device 50 and the immersion membrane reaction tank 55 to equalize temporal fluctuations in flow rate and water quality; Including, An advanced wastewater treatment system using an immersion type separation membrane and a denitrification process, characterized in that the hollow fiber membrane for solid-liquid separation is immersed in the immersion type separation foil reaction tank 55. delete delete The advanced wastewater and wastewater treatment system using an immersion membrane and a denitrification process according to claim 1, further comprising an diffuser for supplying air to the inside of the immersion membrane reaction tank (55). The apparatus of claim 1, wherein the chemical tank (70) further comprises a flocculant injecting means for removing phosphorus. 6. The advanced wastewater treatment system according to claim 5, wherein the flocculant injection unit further comprises a metering pump for constantly injecting the flocculant. The method of claim 1, wherein the denitrification reaction tank 60 further comprises an immersion membrane and the denitrification, characterized in that it further comprises a backwashing means 64 in parallel with air and water to maintain the activity of the denitrification bacteria in the tank Advanced wastewater treatment system using process. The needle according to claim 1, further comprising a backwashing means (62) for storing the backwashing overflowed water of said denitrification reactor (60) in said flow rate adjusting tank (53) via said screen (50). Advanced sewage and wastewater treatment system using knowledge separation membrane and desulfurization process. The apparatus of claim 1, wherein the screen device (50) is a 200 μm mesh screen device. Screening the incoming raw water through the screen device 50; Permeating the separator while supplying air through the immersion membrane reactor (55) to nitrify; Injecting alkalinity and flocculant from the chemical tank (70) to the treated water that has passed through the separator; And The denitrification step of removing nitrogen by autotrophic denitrification using sulfur in an anoxic condition in the denitrification reactor (60); advanced sewage and wastewater treatment method using an immersion membrane and a denitrification process. The method of claim 10, wherein the denitrification step further comprises the step of removing phosphorus through direct filtration. The wastewater using the immersion membrane and the denitrification process according to claim 10, wherein the denitrification step further comprises a backwashing step in which air and water are combined to maintain activity of the denitrifying bacteria in the tank. Advanced treatment method. 12. The method of claim 10, wherein the denitrification step further comprises a backwash phase step of storing the backwashing monthly amount of the denitrification reaction tank 60 in the flow rate adjustment tank 53 via the screen 50. Advanced wastewater treatment method using immersion membrane and desulfurization process. The method of claim 10, wherein the nitrification step comprises a continuous air cleaning step and an intermittent suction operation step. 12. The method of claim 10, wherein the flocculant is alum. 12. The method of claim 10, wherein the alkalinity is Na ₂ CO ₃ or NaHCO ₃ .

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