WO2015102246A1 - Apparatus for treating sludge and wastewater, comprising multistage ph control tank, and method for reducing nitrogen and phosphorus in sludge and wastewater by using same - Google Patents

Abstract

The present invention relates to: an apparatus for treating sludge and waste water by using alkaline sludge, wherein block plates are provided inside a pH control tank so as to increase the retention time of air bubbles, which are discharged from an air bubble supply device, in the pH control tank by interrupting the rise of the air bubbles without micronizing the same, and impact is applied to alkaline sludge in order to allow an alkaline material to be discharged, thereby reducing the energy used for the ventilation of the air bubble supply device of the pH control device; and a method for reducing nitrogen and phosphorus in sludge and wastewater by using the same.

Description

Sewage / Wastewater Treatment System with Multi-stage PH Control Tank and Nitrogen and Phosphorus Reduction Method for Sewage / Wastewater

The present invention removes nitrogen and phosphorus contained in sewage and wastewater, in particular, the total nitrogen is 5 mg / l or less, preferably 2 mg / l or less, the total phosphorus is 0.5 mg / l or less, preferably 0.3 mg / l or less , More preferably, 0.2 mg / l or less, while reducing the amount of blowing in the pH control tank, while achieving the desired pH and dissolved oxygen, an energy-saving sewage and wastewater treatment apparatus and nitrogen of sewage and wastewater using the same; It relates to a phosphorus reduction method.

Generally, sewage and wastewater including municipal sewage, livestock wastewater, agricultural wastewater, and industrial wastewater include nutrients including nitrogen and phosphorus, as well as organic matter, which is a BOD component. The increase of these nutrients destroys the balance of the ecosystem, there is a problem that eutrophication occurs.

Therefore, various methods and devices have been developed to treat nutrients including the organics, nitrogen and phosphorus.

Conventionally, sewage and wastewater treatment methods are mainly for removing organic substances present in sewage and wastewater, and processes such as pretreatment, primary treatment, secondary treatment, and sludge treatment are used. At this time, in the secondary treatment step, a biological treatment was performed to remove organic matter. However, the biological treatment method does not remove nitrogen and phosphorus but has a problem of removing only organic matter.

In order to solve this problem, Korean Patent Laid-Open Publication No. 2000-40351 discloses a wastewater treatment method consisting of a flow control tank, a contact tank, a nitrification tank, a phosphorus absorption tank, a phosphorus discharge tank, a treatment tank, and the like. No. discloses a process for simultaneously treating nitrogen and phosphorus using activated sludge (microorganism) in a bioreactor comprising a first aerobic tank, a first precipitation tank, a second aerobic tank, an anaerobic tank, an anaerobic tank and a third aerobic tank. However, since the activated sludge adsorbs organic matter, there are problems such as a decrease in sludge sedimentation rate and a need for an apparatus for disposing nitrified activated sludge.

In addition, the conventional method for treating sewage and wastewater using a membrane process is to treat organic matters such as BOD and COD, stabilize the suspended solids (SS) generated after denitrification, and treat sewage with high concentration. However, there is a problem that does not satisfy the recently enhanced level of phosphorus treatment.

In Korean Patent No. 1142860, filed by the present applicant and registered in "Alkali Sludge for Reduction, Alkali Sludge Production Method, Phosphorus Reduction Method of Sewage and Wastewater Using Alkali Sludge, and Sewage and Wastewater Treatment System for Performing the Alkali", alkali Sludge can be used to reduce the total phosphorus content of sewage and wastewater to 0.5 mg / l or less, and also, Korean Patent No. 1237408, "Sewage / Wastewater Treatment System with Activated Sludge Retention, and Nitrogen Reduction of Sewage / Wastewater Using the Sludge. Method "not only lowered the total phosphorus content, but also reduced the total nitrogen to 5 mg / l or less. However, in the above patents, in order to utilize the alkaline sludge, air aeration must be continuously performed to maintain the pH of the pH control tank introduced between the anoxic tank and the separation tank at 6.5 to 7.5, thereby reducing the energy cost generated in the pH control tank. There is a need for a way to do this.

An object of the present invention is to use the alkaline sludge to treat the total nitrogen of the sewage and wastewater to 5 mg / l or less, the total phosphorus to 0.5 mg / l or less, while reducing the energy costs used for blowing the air bubble supply device of the pH control tank It is to provide a sewage and wastewater treatment device that can be saved.

Another object of the present invention is to use an alkaline sludge to treat the total nitrogen of sewage and wastewater to 5 mg / l or less, and the total phosphorus to 0.5 mg / l or less, while the energy cost used for blowing the air bubble supply device of the pH control tank. The present invention provides a method for reducing nitrogen and phosphorus in sewage and wastewater using the sewage and wastewater treatment apparatus that can reduce the amount of wastewater.

The present invention for achieving the above object, includes a waste water storage tank, a biological reaction tank and a treatment tank; An alkali sludge tank connected with an alkali compound supply passage and a sludge supply passage, and an alkali sludge tank for producing alkali sludge by stirring the alkali compound and sludge with an agitating device provided, and an alkali sludge for transporting the alkali sludge of the alkali sludge tank to the bioreactor. A conveying passage; The bioreactor is an anoxic tank for removing and denitrifying organic matter from sewage and wastewater containing nitrogen and phosphorus as inflow water, and changing the dissolved phosphorus in the sewage and wastewater introduced from the anoxic tank into insoluble phosphate to be adsorbed onto activated sludge. A pH control tank to nitrate the inflow water and the activated sludge introduced from the pH control tank, and to separate the activated sludge into a membrane and to treat water; The separation membrane tank in the sewage and wastewater treatment apparatus comprising an activated sludge return passage for conveying some of the activated sludge treated in the separation tank to an anoxic tank and an activated sludge discharge passage for discharging some of the activated sludge to the outside. The control tank is provided with an air bubble supply device for supplying air bubbles into the pH control tank, and a blocking plate obstructing the rise of air bubbles discharged from the air bubble supply device is inclined to the water surface, the blocking plate is formed with a plurality of holes It provides a sewage and wastewater treatment apparatus, characterized in that.

According to one embodiment of the invention, the diameter of the nozzle of the air bubble supply device may be 0.5 to 10 mm, preferably 2 to 8 mm.

According to another embodiment of the present invention, the upper end of the obliquely installed blocking plate may be spaced apart from the side wall of the pH adjustment tank to provide an upward passage of air bubbles.

According to another embodiment of the present invention, the lower end of the obliquely installed blocking plate may be spaced apart from the side wall of the pH adjustment tank to provide a down passage of the alkali sludge.

According to yet another embodiment of the present invention, one or more separate blocking plates are additionally installed on the spaced upper portion of the blocking plate, and the blocking plate additionally provided on the upper portion is provided with an air rising passage formed by the blocking plate installed on the lower portion thereof. In order to hinder the rise of air bubbles through the air, the air passage formed by the blocking plate additionally installed in the upper part and the blocking plate installed in the lower part may be formed at different positions when viewed in the vertical direction of the bottom of the pH control tank. have.

According to another embodiment of the present invention, the blocking plate additionally installed in the upper portion of the blocking plate may be installed in a zigzag different inclination direction.

According to another embodiment of the present invention, the hole diameter of the blocking plate may be greater than the diameter of the nozzle of the air bubble supply device.

According to another embodiment of the present invention, the hole diameter of the blocking plate may be 0.6 to 15 mm, preferably 2 to 10 mm.

According to another embodiment of the present invention, the size of the hole of the barrier plate installed in the upper portion may be greater than the size of the hole of the barrier plate installed in the lower portion.

According to another embodiment of the present invention, the size of the hole toward the inclined upper side of the blocking plate may be increased.

According to another embodiment of the present invention, the hole of the blocking plate may be formed in an area adjacent to one end of the blocking plate in contact with the air rising passage.

According to another embodiment of the present invention, the holes formed in the blocking plate installed in the upper portion and the blocking plate provided in the lower, may be formed at different positions when viewed in the vertical direction of the bottom surface of the pH adjustment tank.

According to another embodiment of the present invention, the lower surface of the blocking plate may be formed wrinkles perpendicular to the inclination direction of the blocking plate.

According to another embodiment of the present invention, the depth of the wrinkles toward the inclined upper side of the blocking plate may be deep.

According to another embodiment of the present invention, the angle between any surface parallel to the surface of the pH control tank and the lower surface of the blocking plate may be smaller than the angle between the upper surface of the blocking plate.

According to yet another embodiment of the present invention, the outer or inside the anaerobic tank includes a tubular activated sludge retention portion that decreases in diameter from the top to the bottom, and through the active sludge conveying passage to the upper portion of the tubular activated sludge retention portion After the discharged activated sludge and the sewage and wastewater are supplied, the mixture of activated sludge and the sewage and sewage may be settled to the lower portion of the tubular activated sludge retention part and supplied to the lower portion of the anoxic tank.

According to another embodiment of the present invention, the alkali compound is sodium hypochlorite (NaOCl), calcium hypochlorite (Ca (OCl) ₂ ), sodium hydroxide (NaOH), potassium hydroxide (KOH), sodium bicarbonate ( NaHCO ₃ ), potassium bicarbonate (KHCO ₃ ), magnesium hydroxide (Mg (OH) ₂ ), sodium percarbonate (2Na ₂ CO ₃ -3H ₂ O), calcium hydroxide (Ca (OH) ₂ ), calcium It may be one or more selected from the group consisting of oxide (CaO) and magnesium oxide (MgO).

In addition, the present invention is a method for reducing nitrogen and phosphorus in sewage and wastewater by mixing the sludge with an alkali compound to produce an alkali sludge, and then adding alkali sludge to a bioreactor comprising an oxygen free tank, a pH adjusting tank and a separation membrane tank. By using the sewage and wastewater treatment apparatus, the sewage and wastewater treatment apparatus supplies air bubbles through at least one barrier plate having a hole diameter of 0.6 to 15 mm and an air bubble supply apparatus having a diameter of 0.5 to 10 mm. In order to adjust the amount of blowing air so that the internal conditions of the pH adjusting tank are pH 6.5 to 7.5 and dissolved oxygen 1 to 10 mg / L.

According to one embodiment of the present invention, the alkali sludge may be added in an amount of 5 to 40 parts by volume with respect to 100 parts by volume of activated sludge containing the influent of the bioreactor.

The sewage and wastewater treatment apparatus of the present invention and the method for reducing nitrogen and phosphorus in sewage and wastewater using the same are added to the bioreactor by adding an alkali sludge containing an alkali compound mixed with activated sludge to reduce phosphorus in the sewage and wastewater. In the process of removing nitrogen and phosphorus contained in the pH adjusting tank, a blocking plate is installed inside the pH control tank, thereby preventing the increase without minimizing the air bubbles discharged from the air bubble supply device, thereby increasing the residence time in the pH control tank. While impacting the alkaline sludge to release the alkaline material, it is possible to reduce the energy cost used for blowing the air bubble supply device of the pH control tank. In accordance with the present invention, while reducing the air volume and energy compared to the conventional pH control tank, the pH and dissolved oxygen in the pH control tank can be kept the same, so that the total phosphorus and total nitrogen can be treated at 0.5 mg / l or less and 5 mg / l or less, respectively. .

1 is a view showing a process flow of a wastewater treatment apparatus according to an embodiment of the present invention.

Figure 2 is a cross-sectional view of a conventional pH control tank of the conventional air bubble supply apparatus only installed.

Figure 3a is a cross-sectional view of the pH adjusting tank of another comparative example in which the blocking plate is installed parallel to the water surface of the pH control tank different from the present invention.

Figure 3b is a cross-sectional view of a pH adjusting tank of another comparative example installed so that the lower end of the oblique blocking plate is in contact with the side wall of the pH control tank unlike the present invention.

Figure 3c is a cross-sectional view of the pH adjusting tank of another comparative example in which a plurality of holes are not formed in the obliquely installed blocking plate unlike the present invention.

Figure 4a is formed with three zigzag blocking plate, the blocking plate is formed to be inclined to the surface of the pH control tank, the lower end of the blocking plate is installed so as to be spaced apart from the side wall of the pH control tank, a plurality of holes in the blocking plate A cross-sectional view of a pH adjusting tank according to one embodiment of the present invention formed to be deflected on the conveying passage side.

4B is a partial plan view of the blocking plate installed at the bottom of the pH adjusting tank of FIG. 4A. FIG. 4C is a partial plan view of the blocking plate installed in the middle of the pH adjusting tank of FIG. 4A.

Figure 5a is formed with four zigzag block plates, the block plate is formed to be inclined to the surface of the pH control tank, the lower end of the block plate is installed so as to be spaced apart from the side wall of the pH control tank, a plurality of holes formed in the block plate And, it is a cross-sectional view of the pH adjusting tank according to another embodiment of the present invention formed wrinkles perpendicular to the inclined direction on the lower surface of the blocking plate.

FIG. 5B is an enlarged cross-sectional view of a blocking plate installed at the lowermost side of the pH adjusting tank of FIG. 5A, and the wrinkles are formed so that the wrinkles are lowered toward the other end from the side of the air transfer passage in a direction perpendicular to the inclined direction on the lower surface of the blocking plate.

FIG. 5C is a partial plan view of the upper surface of the blocking plate installed at the bottom of the pH adjusting tank of FIG. 5A, in which a plurality of holes in the blocking plate are formed while the diameter decreases from the side of the air transfer passage to the other end.

6 is a cross-sectional view of a blocking plate according to another embodiment of the present invention, wherein an angle between an arbitrary surface parallel to the water surface of the pH adjusting tank and a lower surface of the blocking plate is smaller than an angle between the upper surface of the blocking plate. .

In the present invention, by installing a blocking plate inside the pH control tank, it prevents the rise without miniaturizing the air bubbles discharged from the air bubble supply device, while increasing the residence time in the pH control tank, alkali sludge to release alkaline substances The present invention relates to a sewage and wastewater treatment apparatus using alkaline sludge and to a method for reducing nitrogen and phosphorus in sewage and wastewater using the same, by applying a shock to it, so as to reduce the energy cost used for blowing air bubbles in the pH control tank.

Hereinafter, the present invention will be described in detail with reference to FIG. 1.

As shown in FIG. 1, the wastewater treatment apparatus of the present invention includes a bioreactor 100 and an alkali sludge tank 200 for removing phosphorus by adding alkaline sludge to adjust pH.

The bioreactor 100 is an apparatus including one or more tanks selected from the anaerobic tank 110, the pH control tank 120 and the separation membrane tank 130, the treatment tank 140 is provided at the rear end of the bioreactor 100 Can be.

1 shows that the alkali sludge tank 200 is provided on one side of the pH control tank 120, but this shows an embodiment of the present invention. The alkali sludge tank 200 is provided as part of the bioreactor in any structure of the bioreactor, preferably provided on one side of any one of the anoxic tank 110, pH control tank 120 and separation membrane tank 130. The alkaline sludge is introduced through the alkali sludge feed passage c.

The alkali sludge tank 200 produces an alkali sludge by mixing the alkali compound and the sludge with a stirring device (M) to inject the alkali compound into the sludge. At this time, the alkali compound is supplied from the alkali compound supply passage (a) connected to the alkali sludge tank 200, and the sludge is supplied from the sludge supply passage (b) connected to the alkali sludge tank 200.

In this case, the sludge may be activated sludge returned from any one or more of the anoxic tank 110, the pH control tank 120 and the separation membrane tank 130, or may be a sludge supplied from the outside.

The anoxic tank 110 removes organic substances by agitating the sewage, wastewater and activated sludge, which are the incoming water, with the stirring device (M) to feed organic matter present in the sewage and wastewater, and separating membrane tank 130. The nitrified activated sludge returned from is denitrified by inducing denitrification under anoxic conditions and releasing nitrogen gas into the atmosphere.

In addition, the pH control tank 120 adjusts the pH of the inflow water from which the organic matter and the nitrogen are removed from the anoxic tank 110 to insoluble phosphate by aggregating the divalent and trivalent cations present in the inflow water with the dissolved phosphorus in an alkaline state. And insoluble phosphate is adsorbed onto the activated sludge.

In addition, the separation tank 130 nitrates the ammonia nitrogen and activated sludge of the influent water introduced from the pH control tank 120.

The nitrified influent and activated sludge pass through the immersion membrane, and the treated water passing through the separator is discharged to the treatment tank 140, and some of the activated sludge (activated sludge adsorbed with insoluble phosphate) that does not pass through the membrane. Is returned to the oxygen-free tank 100 along the activated sludge return passage (d) and the other part is discharged to the outside along the activated sludge discharge passage (e). In addition, it is possible to transfer the activated sludge treated in the separation membrane to the alkali sludge tank 200 along the alkali sludge conveyance passage (not shown).

The membrane (Membrane) installed in the separation membrane tank 130 is one or two or more selected from flat membrane, hollow fiber membrane and tubular membrane according to the shape, the pore size of the membrane cartridge filter, MF (Microfiltration) and UF (Ultrafiltration) ) Or two or more kinds thereof may be used.

The membrane tank 130 supplies air through the diffuser to maintain an aerobic state, but in general, dissolved oxygen (DO) is adjusted in the range of 1 to 5 mg / l, forming stirring and water flow, and the separation membrane Air cleaning can prevent clogging.

In addition, the treated water tank 140 is introduced into the treated water passing through the separation membrane in the separation membrane tank 130, and processes it to store and discharge the treated water.

The present invention includes a sewage and waste water storage tank, a bioreactor 100 and a treated water tank 140; An alkali sludge tank 200 connected with an alkali compound supply passage and a sludge supply passage and agitating the alkali compound and the sludge with an agitating device provided therein, and transferring the alkali sludge of the alkali sludge tank to the bioreactor. It includes an alkaline sludge conveying passage; The bioreactor 100 is an anoxic tank 110 for removing and denitrifying organic matter in the sewage and wastewater containing nitrogen and phosphorus as inflow water, the dissolved phosphorus of the sewage and wastewater introduced from the anoxic tank as an insoluble phosphate. A pH control tank (120) for changing and adsorbing to activated sludge, and a separation membrane tank (130) for nitrifying inflow water and activated sludge introduced from the pH control tank and membrane separation of the activated sludge; The separation membrane tank 130 is a sewage and wastewater treatment apparatus including an activated sludge return passage for conveying some of the activated sludge treated in the separation tank to an anoxic tank and an activated sludge discharge passage for discharging some of the activated sludge to the outside. In this case, the pH control tank 120 is an air bubble supply device for supplying air bubbles into the pH control tank, and the air bubbles discharged from the air bubble supply device without hindering the increase without minimizing the rise of air bubbles A blockage plate is installed inside the pH control tank while interfering with the alkali sludge so that the alkaline material is released while increasing the residence time in the pH control tank without hindering the air bubbles discharged from the air bubble supply device. Impact barriers.

The pH control tank 120 is an organic material that is eluted from the alkali compound derived from the alkali compound collected in the alkaline sludge by the impact amount of the air bubbles discharged through the air bubble supply apparatus 121 and the organic material flowing from the oxygen-free tank 110 and By adjusting the pH of the nitrogen-influent influent, the divalent and trivalent cations present in the influent aggregate with the dissolved phosphorus in an alkaline state to form insoluble phosphate and adsorb the insoluble phosphate to the activated sludge.

In general, air aeration is carried out to supply oxygen to the microorganisms in the sludge, and aims to increase the dissolved oxygen concentration in the liquid phase.In order to increase the dissolved oxygen concentration, the gas-liquid interface is widened and the bubble rising rate slows the contact at the gas-liquid interface. It is common to form microbubbles in order to increase the time, and the pH decreases when the dissolved oxygen concentration in the liquid phase increases.

However, in the pH control tank 120 of the present invention, the alkali sludge is separately supplied together with the inflow water from which the organic matter and nitrogen removed from the anoxic tank 110 are removed, and the air bubbles discharged by the air bubble supply device 121 are alkali sludge. After the impact, the alkaline substance derived from the alkali compound collected in the alkaline sludge is eluted to adjust the pH of the pH adjusting tank to 6.5 to 7.5, preferably 6.7 to 7.3, more preferably 6.8 to 7.2. In the pH range, divalent and trivalent cations aggregate with dissolved phosphorus to form insoluble phosphate.

Therefore, since the pH control tank of the present invention does not increase the dissolved oxygen concentration through the air bubble supply device 121, it is rather necessary to supply relatively large air bubbles without adjusting to several tens of micrometers or even several tens of nm or less to the alkaline sludge. It is further provided with a blocking plate (122a, 122b, 122c, 122d) to be able to elute the alkaline substance by applying an impact, and to fuse the bubbles together while preventing the rise of the air bubbles discharged from the air bubble supply apparatus 121. As a result, it is possible to increase the amount of air bubbles blown out of the air bubble supply device 121 or to add an impact amount above the critical point at which the alkaline material is eluted to the alkaline sludge without increasing the air bubble discharge pressure.

The size of the air bubbles discharged from the air bubble supply device 121 is 0.5 to 10 mm, preferably 2 to 8 mm, as a micro unit. In order to discharge the air bubbles below the lower limit, the cost of equipment and energy cost for the manufacture of microbubbles increases, and when the air bubbles below the lower limit are discharged, the dissolved oxygen concentration increases, but the amount of impact applied to the alkali sludge is small and the alkali sludge is reduced. The lower the elution of the alkaline substance in the above, while the fine air bubbles below the lower limit raise and float the alkali sludge, so that the pH is lower than the range defined by the present invention, so that insoluble phosphate formation is reduced, and phosphorus removal efficiency is lowered. In addition, the discharge of air bubbles exceeding the upper limit may increase the pH, so the purpose of aggregation may be achieved, but the dissolved oxygen supply is insufficient and the activated sludge microorganism growth environment in the bioreactor is destroyed, and the sewage and wastewater treatment cannot be continued.

The blocking plate is preferably at least one end of the blocking plate is spaced apart from the side wall of the pH control tank in order to provide a rising passage of the air bubbles. However, in the case where the air bubble hole is formed in the blocking plate, the air bubble hole may function as a rising passage of the air bubble, so that the air bubble rising passage is not provided separately even if one end of the blocking plate is not separated from the side wall of the pH control tank. You may not.

In addition, the lower end of the obliquely installed blocking plate is preferably spaced apart from the side wall of the pH control tank to provide a down passage of the alkali sludge.

In addition, one or more separate blocking plates may be additionally installed on the spaced upper portion of the blocking plate, and 2 to 20, preferably 3 to 10 blocking plates may be installed in the pH adjusting tank. 4A illustrates an embodiment in which three blocking plates are installed, and FIG. 5A illustrates an embodiment in which four blocking plates are installed. Taking FIG. 4A as an example, the blocking plate 122b additionally installed at the upper portion may block the rising of air bubbles through the air rising passage formed by the blocking plate 122a installed at the lower portion thereof. Air rise passage formed by the plate and the blocking plate installed on the bottom may be formed at different positions when viewed in the vertical direction of the bottom of the pH control tank.

In addition, as shown in FIG. 4A, the air bubble holes formed in the blocking plate 122b provided at the upper portion and the blocking plate 122a provided at the lower portion thereof are preferably formed at different positions when viewed in the vertical direction of the bottom surface of the pH adjusting tank. 4b and 4c, the bubble hole may be formed in different areas, that is, one end area close to the air movement passage and the other end area opposite thereto, when viewed in the vertical direction of the bottom of the pH control tank, but not separately shown. However, even if the areas have the same or overlapping areas, the position of the air holes may be set so that the air bubbles rising from the bottom blocking plate do not enter the air bubble hole of the upper blocking plate but hit the surface of the upper blocking plate. It can be different. The air bubble hole may be formed in an area adjacent to one end of the blocking plate in contact with the air rising passage as shown in FIG. 4A, and an area adjacent to one end of the blocking plate is defined at one end when the width of the blocking plate is constant. When the length from the opposite end to 100 is 100, it means the area calculated from the length from one end to 10 to 50, and preferably from one end to 30.

The air bubble hole 1220b of the blocking plate 122b installed in the upper portion may have the same size as the air bubble hole 1220b of the blocking plate 122a installed in the lower portion, but the air of the blocking plate 122a installed in the lower portion thereof may be the same. As air bubbles rise through the bubble hole 1220b or the air movement passage, the bubbles are agglomerated and become larger, so that the air bubble hole 1220b of the blocking plate 122b provided on the upper side is smaller than the air bubble hole 1220b of the lower part. Larger is preferred (see FIGS. 4A-4C).

In addition, as shown in FIG. 5C, the size of the air bubble hole may be increased toward the inclined upper side even in one blocking plate.

The size of the air bubble hole may vary depending on how many times the air bubble supply device 121 is installed from the air bubble supply device 121 or close to the inclined upper side close to the air moving passage even in the blocking plate, but at least the air bubble supply device 121 ) Is the size of the air bubbles supplied, i.e., the nozzle diameter of the air bubble supply device, and the diameter of the air bubbles hole is 0.6 to 15 mm, preferably 2 to 10 mm.

When the blocking plate is formed parallel to the surface of the pH control tank as shown in Figure 3a, sludge (α) is deposited on the upper block plate, the oxygen is not supplied to the deposited sludge, the sludge inside the anaerobic condition is black sludge As it changes, the microbial growth environment is destroyed. Therefore, it is preferable that the blocking plate is installed to be inclined so that the air bubbles hit the blocking plate again while impacting the alkali sludge, and at the same time, the sludge does not accumulate and settles below the pH control tank (see FIGS. 4A and 5A). ). When the barrier wall is installed to be inclined, the inclination angle based on the water surface is 5 ° to 45 °, preferably 10 ° to 30 °, and below the lower limit, slip and settling of the sludge accumulated on the upper part of the block is delayed and the inside of the sludge is delayed. It may be anaerobic condition, and when the upper limit is exceeded, the height of the pH adjusting tank may be too high to install a plurality of blocking plates inside the pH adjusting tank, or it may be difficult to install a plurality of blocking plates in two to five stages. . The blocking plate additionally installed in the upper portion of the blocking plate is preferably installed in a zigzag different inclination direction.

On the other hand, the angle between the lower surface of the blocking plate in contact with the rising air and the upper surface of the blocking plate in which the sludge slips, the angle between any surface parallel to the water surface of the pH control tank and the lower surface of the blocking plate as shown in FIG. It may be formed smaller than the angle between the upper surface of the blocking plate.

Meanwhile, wrinkles 1221a may be formed on a lower surface of the blocking plate 122a in a direction perpendicular to the inclination direction of the blocking plate (see FIG. 5A). Since the wrinkles are formed on the lower surface of the blocking plate, the air bubbles raised from the air bubble supply device 121 may collide with the lower surface of the blocking plate and pass through the wrinkles to more easily induce the aggregation of the air bubbles.

In addition, the depth of the wrinkles may be deeper toward the inclined upper side of the blocking plate, and may be d1 (lower wrinkle depth) <d2 (upper wrinkle depth) as shown in FIG. 5B.

On the other hand, sewage and waste water are introduced into the anaerobic tank through the sewage and wastewater inflow passage with the upper part opened in the air, and oxygen is dissolved while contacting the air. Since a flow is formed and oxygen is dissolved in contact with the air in the atmosphere, the dissolved oxygen in the upper layer of the anoxic tank rises to about 0.1 to 0.3, so that the denitrification efficiency is reduced. And a tubular activated sludge retention portion that decreases in diameter toward the bottom, and after the activated sludge discharged through the activated sludge conveying passage to the upper portion of the tubular activated sludge retention passage and the sewage and wastewater are respectively supplied, the tubular activated sludge retention In the lower part, a mixture of activated sludge and sewage and wastewater is settled. It is preferable to be fed to the lower part of the group. The tubular activated sludge retention part is an oxygen-free tank by allowing the microorganisms in the activated sludge to be consumed before the activated sludge to be returned is separated from the oxygen-free tank, as well as the oxygen dissolved in the incoming sewage and wastewater. Dissolved oxygen can be lowered and maintenance costs are rarely in place once installed. In other words, activated sludge microorganisms living in aerobic conditions in the separation membrane tank of oxygen dissolved in the sewage and wastewater are suddenly returned and consumed even a small amount of oxygen from the sewage introduced by the oxygen supply is cut off. It is possible to achieve the full consumption of oxygen at.

The volume of the tubular activated sludge retention part is 10 to 40, preferably 20 to 35 with respect to 100 of the oxygen free tank volume, and the residence time in the tubular activated sludge retention part is 2 to 20 minutes, preferably 5 to 15 minutes. . When the volume of the tubular activated sludge retention portion or the residence time in the retention portion is less than the lower limit, the dissolved oxygen reduction effect and the total nitrogen content reduction effect thereof are not sufficient, and when the upper limit value is exceeded, the effect is no longer effective. Without increase, the volume of sewage and wastewater treatment system becomes large and the treatment time becomes long.

The lower portion of the anoxic tank in which the activated sludge settled under the tubular activated sludge retention portion is 30 to 80, preferably 40 to 70 when the height of the anoxic tank is 100. When the height of the anoxic tank is less than the lower limit, the supply of activated sludge through the lower portion of the tubular activated sludge retention part may not be smooth due to the sludge settled in the lower part of the anoxic tank, and when the upper limit is exceeded, the residence time of the activated sludge is As a result, the dissolved oxygen reduction effect and the total nitrogen content reduction effect may not be sufficient.

Alkali sludge of the present invention is prepared by adding an alkali compound to the sludge and mixing them.

The alkali sludge is prepared by mixing an alkali compound and a sludge to accumulate an alkali compound in the sludge. When the alkali sludge is added to a bioreactor, the alkali sludge is mixed with activated sludge to reduce phosphorus in sewage and wastewater and directly add an alkali compound. Unlike the case, it is not only possible to prevent the killing of microorganisms of activated sludge, but also to easily maintain a constant pH.

The time for adding and mixing the alkali compound to the sludge is 2 to 12 hours, preferably 4 to 10 hours. When the mixing time is less than 2 hours, the alkali compound is difficult to accumulate in the sludge. When the mixing time is more than 12 hours, the alkaline compound is no longer accumulated in the activated sludge and the process time is longer.

In the mixing step in which the sludge and the alkali compound are mixed, the alkali compound is added throughout the mixing step.

The step of adding the alkali compound to the entire mixing step is preferably a step of stirring while dividing the alkali compound into the sludge 10 to 50 times intermittently, or may be a step of continuously injecting the alkali compound.

The concentration of the alkali compound added to the sludge is 1 to 5% by weight, preferably 2 to 4% by weight. When the concentration of the alkali compound exceeds the upper limit, the sludge that collects the alkali compound is decomposed or solubilized, so that an alkali sludge having a desired volume cannot be obtained, and the phosphorus reduction efficiency is lowered below the lower limit.

The step of intermittently adding the alkali compound is a step of repeating the process of injecting the alkali compound for 3 to 8 minutes while stirring the sludge, stopping the injection of the alkali compound and stirring for 8 to 15 minutes 10 to 30 times to be.

The mixing process of the sludge and the alkali compound by the intermittent injection of the alkali compound, for example, in the preparation of 100L alkaline sludge (based on 0.7% by weight of solids content) with 3% by weight of alkali compound in the alkali compound injection step of 2 to 2 per minute 50 ml, preferably 3 to 20 ml.

In addition, in the process of continuously injecting the alkali compound, 1 to 20 ml per minute is added to 3 wt% of the alkali compound when preparing 100 L alkali sludge (based on 0.7 wt% of solid content) for 2 to 12 hours. In this case, the input amount of the alkali compound may be adjusted according to the volume of the alkaline sludge to be prepared, the solid content, and the concentration of the alkali compound.

In the case of not injecting the alkali compound or injecting the alkali compound at once according to the conditions of the process, the insoluble phosphate may not be formed when the alkali compound is supplied to the bioreactor due to the sludge solubilization, and the alkali compound is not accumulated in the sludge. have.

3% by weight of the alkali compound contained in the alkali sludge is 0.05 to 15% by volume, preferably 0.1 to 10% by volume, more preferably 0.5 to 5, based on the total volume of the alkali sludge (based on 0.7% by weight of solids content). It is added in volume%. Since the input amount of the alkali compound is an input amount of the alkali compound based on the concentration of 3% by weight, when using a concentration other than 3% by weight of the input alkali compound, the input amount of the alkali compound can be adjusted by diluting according to the concentration. have. In addition, if the sludge solid content is out of 0.7% by weight accordingly according to the increase in the content of the sludge solid content is adjusted to increase the content of the alkali compound to be added.

When the content of the alkali compound in the alkali sludge is less than the lower limit, the desired pH is not obtained, and insoluble phosphate is insufficient to form phosphorus, resulting in low phosphorus reduction efficiency, and when the content is above the upper limit, the activity of the microorganisms in the activated sludge in the bioreactor. To lower the water treatment efficiency of the bioreactor.

The pH of the alkali sludge is 7.5 to 8.5, preferably 7.7 to 8.2.

In addition, when the alkali sludge is measured by low-speed stirring the slurry state based on the sludge solid content 0.7% by weight, the alkalinity is 40 to 60 mg / l.

The alkalinity is measured by stirring activated sludge or alkali sludge in a slurry state, for example, a sludge having a solid content of 0.7% by weight at 80 to 150 rpm, and the alkalinity of the alkaline sludge and the activated sludge is in a similar range. The alkalinity of the alkali sludge accumulated in the alkali compound and the alkalinity of the activated sludge appear to be similar because the alkalinity of the liquid phase is measured among the alkaline sludge components in the slurry state, and the alkalinity caused by the injected alkali compound is the inside of the solid sludge. It was judged that the activated sludge and the alkali sludge did not show a significant difference in the alkalinity of the liquid portion except the sludge. Experimentally, when the same amount of alkali compound in the sludge is added to the sludge at once, the alkalinity is rapidly increased to 100 to 120 mg / l, and the alkali sludge of the present invention can be seen that the alkali compound is collected. .

Although the sludge of the said alkali sludge is not specifically limited as sludge normally used, Preferably it is activated sludge, surplus sludge, the concentrated sludge which concentrated these, or dehydration cake.

The activated sludge may be activated sludge returned from a separation membrane tank of a bioreactor or activated sludge generated in another sewage / wastewater treatment apparatus, and excess sludge is sludge generated in a sewage / wastewater treatment apparatus. In addition, the concentrated sludge is concentrated by the sludge thickener or gravity sedimentation so that the activated sludge or excess sludge to a solid content of 1 to 5% by weight, the dewatering cake is compressed by pressing the activated sludge, surplus sludge or concentrated sludge with a dehydrator solid content 15 To 25 wt%. The concentrated sludge may be used by diluting 1 to 5 times, but may be used by suspending as it is, and dehydrating cake is used by diluting 3 to 20 times so that cake cakes do not aggregate.

In addition, the alkali compound is sodium hypochlorite (NaOCl), calcium hypochlorite (Ca (OCl) ₂ ), sodium hydroxide (NaOH), potassium hydroxide (KOH), sodium bicarbonate (NaHCO ₃ ), potassium bicarbonate (KHCO ₃ ), Magnesium hydroxide (Mg (OH) ₂ ), sodium percarbonate (2Na ₂ CO ₃ -3H ₂ O), calcium hydroxide (Ca (OH) ₂ ), calcium oxide (CaO) and magnesium oxide (MgO) At least one selected from the group consisting of.

Alkali sludge thus prepared may be used directly in a state in which an alkali compound is accumulated in the sludge, but may be used by concentrating to 1 to 25% by weight of solid content using a sludge thickener or a dehydrator. The sludge thickener or dehydrator is used to dilute the alkali sludge 3 to 20 times so as not to aggregate into the bioreactor.

Alkali sludge is supplied to the bioreactor and used in sewage and wastewater treatment, so that the alkali compounds accumulated in the sludge are eluted little by little and can be used for one to three months. The alkali compound is slowly eluted from the alkali sludge, and the amount of the eluted compound may be increased when the air aeration intensity is enhanced.

The alkali sludge is preferably added in an amount of 5 to 40 parts by volume with respect to 100 parts by volume of activated sludge containing the influent of the bioreactor.

Meanwhile, the present invention provides a method for reducing nitrogen and phosphorus in sewage and wastewater using the alkaline sludge and sewage and wastewater treatment apparatus.

In general, the membrane bioreaction process (MBR) maintains a high concentration of activated sludge and also maintains a sludge residence time (SRT) for high efficiency removal of organic matter and nitrogen. In this case, nitrogen removal is efficiently generated by extending the denitrification time. While there may be an advantage, the phosphorus is re-dissolved in the sludge ingesting excess phosphorus has a disadvantage of low treatment efficiency.

In order to overcome the above disadvantages, the method for reducing nitrogen and phosphorus in sewage and wastewater according to the present invention includes preparing an alkali sludge by injecting an alkali compound into the sludge and adding the alkaline sludge to the bioreactor.

After the alkali sludge is added to the bioreactor, the pH is adjusted, and the divalent and trivalent cations present in the sewage and waste water aggregate with dissolved phosphorus (PO ₄ ^3- ) in an alkaline state to form scale and aggregate. The insoluble phosphate, which is a scale, is adsorbed on the activated sludge so that phosphorus does not re-dissolve and it is easy to remove a large amount of phosphorus.

The bioreactor includes an anoxic tank, a pH adjusting tank, and a separation membrane tank, wherein alkaline sludge is added to any one of the three tanks at one time, and is evenly distributed through the inner transport passage. The alkaline sludge is added at a time and stays in the bioreactor to slowly elute the alkali compound to adjust the pH of the bioreactor. Therefore, there is no need to continuously add alkaline sludge to control the pH of the bioreactor.

The content of alkali sludge added to the bioreactor is 5 to 40 parts by volume, preferably 10 to 35 parts by volume with respect to 100 parts by volume of activated sludge containing the influent of the bioreactor. If the content is less than 5 parts by volume, the cycle for which alkaline sludge should be added is short and does not maintain the desired pH to form insoluble phosphate. If the content is more than 40 parts by volume, the amount of activated sludge present in the bioreactor is This relatively small organic decomposition may not occur.

The pH value of the bioreactor added with the alkali sludge is 6.5 to 7.5, preferably 6.7 to 7.3, more preferably 6.8 to 7.2. When the pH is less than 6.5, insoluble phosphate is not formed. When the pH is greater than 7.5, microorganisms of activated sludge are killed and the total phosphorus of the treated water has a value of more than 0.5 mg / L.

The pH is controlled by spontaneous elution by the addition of alkali sludge, and physical control is possible by adjusting the amount of air blown from the reaction solution of the bioreaction tank into which the alkali sludge is added, that is, the air bubble supply device of the pH control tank. In general, the pH is acidic when the dissolved oxygen increases when the air bubble is supplied by adding an air aeration, but in the present invention, the air bubble supplied by the air bubble supply device impacts the alkali sludge, and the alkali compound accumulated in the alkali sludge is accumulated. This can be eluted to the outside to adjust the pH to the above range. Dissolved oxygen (DO) of the pH adjustment tank is adjusted to 1 to 10 mg / l, preferably 1 to 5 mg / l, more preferably 1 to 3 mg / l.

In addition, when the divalent and trivalent cations present in the sewage and wastewater to be combined with the dissolved phosphorus are insufficient, Al, Ba, Ca, Cu, Fe, Mg, Mn, Zn, Be, and Sr are divalent and trivalent cations. At least one selected from the group consisting of Ra, Sc, Ti, V, Cr, Mn, Co, Ni, Ga, Ge, As, Se, Sn, Sb, and Pb. It can be added to one bath.

The divalent and trivalent cations added may be recycled divalent and trivalent cations. Specifically, the reverse osmosis unit (R / O device) is further provided at the rear of the bioreactor to treat the treated water passing through the bioreactor by the reverse osmosis device (R / O device) material contained in the filtered water ( Divalent and trivalent cations) are recycled to the bioreactor. In addition, the water treated with the reverse osmosis device (R / O device) can be used as recycled water.

In addition, the nitrogen and phosphorus reduction method of sewage and wastewater of the present invention further comprises the step of removing and denitrifying the organic matter of the sewage and wastewater introduced into the bioreactor and / or membrane separation of the activated sludge adsorbed the insoluble phosphate. It may include.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

Examples 1-2 and Comparative Examples 1-5

Using the advanced treatment apparatus of the present invention, the wastewater was treated according to the conditions as shown in Tables 1 and 2 below based on 400 L / day. In the alkaline sludge tank, the alkaline compound was injected into the sludge for 5 minutes at 3.775 ml per minute for 5 minutes and the stirring was repeated for 10 minutes without the injection of the alkaline compound for 6 hours, and the sludge used activated sludge returned from the separation membrane bath.

At this time, the total volume of the activated sludge and the alkaline sludge of the bioreactor is 131.53 ℓ.

Each of the volumes contained in the anoxic tank, the pH control tank and the membrane tank of the bioreactor was 43.94 L, 8.45 L and 79.14 L, in particular the pH control tank is 260, 50 and 750 mm in width, length and height, respectively, 650 mm.

In Comparative Example 1, there is no blocking plate in the pH adjusting tank, and in Comparative Example 2, a blocking plate without an air bubble hole having an area of 68.25m ² (195mm x 35mm) is installed parallel to the surface of the pH adjusting tank as shown in FIG. 3A. It is installed in three stages rather than two stages, Comparative Example 3 is a blocking plate without an air bubble hole of an area 68.25m ² (195mm x 35mm) in the pH control tank as shown in Figure 3b in a zigzag form at a 20 ° angle to the surface of the pH control tank It is installed in three stages, but not two stages (Fig. 3b), Comparative Example 4 is a blocking plate without an air bubble hole in the pH control tank with an area of 68.25m ² (195mm x 35mm) as shown in Figure 3c zigzag at an angle of 20 ° It is installed in the form.

In addition, the pH adjusting tank of Example 1 has an area of 68.25 m ² (195 mm x 35 mm) in the pH adjusting tank similar to FIG. 4A, and holes 2 mm in diameter are formed in the lower blocking plate at intervals of 3 mm in width and length, respectively, and intermediate blocking. The plate is formed with a hole of 2.5 mm in diameter, and the upper block is provided with holes having a diameter of 3 mm in a zigzag form at a 20 ° angle on the surface of the water, and is approximately 40% adjacent to the air conveying passage instead of the entire surface of the block. Only holes are formed in the area.

In addition, the pH adjusting tank of Example 2 has an area of 68.25 m ² (195 mm x 35 mm) in the pH adjusting tank similar to FIG. 5A, and a hole having a diameter of 2 mm is formed on the lower side of the inclined blocking plate, and the hole becomes larger toward the top. 3.5 mm holes are formed on the upper side, each of which is installed in a zigzag form at a 20 ° angle on the surface of the water, and holes are formed on the entire surface of the blocking plate, and a wrinkle having a height of 1 mm is formed on the lower lower surface of the blocking plate. And, the wrinkles are higher toward the top, and the upper side is formed with a wrinkle of 3 mm in height, it is formed in three stages rather than four stages, unlike FIG. 5A.

Comparative Examples 1 to 4 and Examples 1 and 2 are blown through an air bubble supply device having a diameter of 2 mm of the nozzle in the pH adjusting tank, except that Comparative Example 5 uses the same type of pH adjusting tank as Example 1. However, the nozzle of the air bubble supply device is to supply fine air bubbles with a diameter of 0.1 mm.

In addition, the blower was blown by using a blower of 40 Wh, the air volume of 40 L / min, 20% of the nozzles connected to the blower was connected to the pH control tank, the rest was connected to the separation membrane tank to perform the blow. If the airflow control is necessary, the airflow was adjusted by using an inverter.

In addition, the pH of the sewage and wastewater introduced into the anoxic tank is 7.0 to 7.5, and the pH of the alkaline sludge is 7.8. In addition, the flat membrane MF used in the membrane tank is a membrane having a pore size of 0.1 to 0.4 ㎛ prepared in Yuasa.

Table 1

division		Comparative Example 1	Comparative Example 2	Comparative Example 3	Comparative Example 4
Tubular activated sludge retention	shape	Plate type	Plate type	Plate type	Plate type
	Height 1)	40	40	40	40
	DO (mg / L) 2)	0.17	0.18	0.17	0.16
	Residence time (min)	6.69	6.69	6.69	6.69
	Volume (L) 3)	6.50	6.50	6.50	6.50
Anaerobic	MLSS concentration (mg / l)	7150	7210	7040	7100
	Alkali sludge injection amount (L)	-	-	-	-
	Internal transfer rate (%)	250	250	250	250
	Stirring Speed (RPM)	180	180	180	180
	DO (mg / L) 4)	0.00	0.00	0.00	0.00
	DO (mg / L) 5)	0.00	0.00	0.00	0.00
	ORP (mmV)	-201	-198	-220	-214
	Retention time (hr)	2.64	2.64	2.64	2.64
Alkali Sludge Tank	MLSS concentration (mg / l)	8780	8840	8710	8680
	MLSS amount (L)	33	33	33	33
	Alkali Chemical Concentration (%) (NaOCl)	3	3	3	3
	Alkali chemical injection amount (ml)	453	453	453	453
	Drug injection time (hr)	6	6	6	6
	Injection position	pH adjustment tank	pH adjustment tank	pH adjustment tank	pH adjuster
pH adjustment tank	MLSS concentration (mg / l)	7790	7840	7710	7680
	Block plate presence and shape	none	3a	3b	Fig 3c
	DO (mg / l)	2.1	1.8	1.8	1.7
	pH	7.07	7.06	7.06	7.07
	Alkali sludge injection amount (L)	33	33	33	33
	Retention time (hr)	0.51	0.51	0.51	0.51
Membrane	MLSS concentration (mg / l)	8260	8310	8190	8220
	Alkali sludge injection amount (L)	-	-	-	-
	pH	7.05	7.03	7.04	7.04
	DO (mg / l)	2.5	2.4	2.5	2.4
	Retention time (hr)	4.74	4.74	4.74	4.74
	Membrane Type	Flat membrane MF	Flat membrane MF	Flat membrane MF	Flat membrane MF
Total residence time (hr)		7.89	7.89	7.89	7.89

1) The height means the height of the tubular activated sludge retention zone when the oxygen free tank height is 100.

2) DO is the dissolved oxygen concentration measured in the upper sample (5 cm deep from the surface) of the tubular activated sludge reservoir.

3) The volume is the relative volume of the tubular activated sludge retention zone when the volume of the anaerobic bath is 100.

4) DO is the dissolved oxygen concentration measured in the upper sample (5 cm deep from the surface of the anoxic tank).

5) DO is the dissolved oxygen concentration measured in an anaerobic lower layer sample (40 cm deep from the surface of the water).

TABLE 2

division		Example 1	Example 2	Comparative Example 5
Tubular activated sludge retention	shape	Plate type	Plate type	Plate type
	Height 1)	40	40	40
	DO (mg / L) 2)	0.16	0.17	0.16
	Residence time (min)	6.69	6.69	6.69
	Volume (L) 3)	6.50	6.50	6.50
Anaerobic	MLSS concentration (mg / l)	7190	7200	7180
	Alkali sludge injection amount (L)	-	-	-
	Internal transfer rate (%)	250	250	250
	Stirring Speed (RPM)	180	180	180
	DO (mg / L) 4)	0.00	0.00	0.00
	DO (mg / L) 5)	0.00	0.00	0.00
	ORP (mmV)	-205	-208	-224
	Retention time (hr)	2.64	2.64	2.64
Alkali Sludge Tank	MLSS concentration (mg / l)	8730	8800	8830
	MLSS amount (L)	33	33	33
	Alkali Chemical Concentration (%) (NaOCl)	3	3	3
	Alkali chemical injection amount (ml)	453	453	453
	Drug injection time (hr)	6	6	6
	Injection position	pH adjustment tank	pH adjustment tank	pH adjustment tank
pH adjustment tank	MLSS concentration (mg / l)	7730	7800	7830
	Block plate presence and shape	Figure 4a	Figure 5a	4a fine air
	DO (mg / l)	1.7	1.5	3.4
	pH	7.06	7.08	6.46
	Alkali sludge injection amount (L)	33	33	33
	Retention time (hr)	0.51	0.51	0.51
Membrane	MLSS concentration (mg / l)	8240	8160	8170
	Alkali sludge injection amount (L)	-	-	-
	pH	7.05	7.06	6.52
	DO (mg / l)	2.4	2.5	2.7
	Retention time (hr)	4.74	4.74	4.74
	Membrane Type	Flat membrane MF	Flat membrane MF	Flat membrane MF
Total residence time (hr)		7.89	7.89	7.89

Experimental Example 1

The BOD, COD, SS, T-N, T-P and total coliform bacteria were measured for the Examples and Comparative Examples, and the results are shown in Tables 3 and 4 below.

TABLE 3

division	Comparative Example 1			Comparative Example 2			Comparative Example 3			Comparative Example 4
	Influent (mg / ℓ)	Treated water (mg / l)	Processing efficiency (%)	Influent (mg / ℓ)	Treated water (mg / l)	Processing efficiency (%)	Influent (mg / ℓ)	Treated water (mg / l)	Processing efficiency (%)	Influent (mg / ℓ)	Treated water (mg / l)	Processing efficiency (%)
BOD	149.5	1.2	99.2	151.0	1.4	99.1	174.6	1.6	99.1	156.5	1.6	99.0
COD	122.4	6.0	95.1	127.1	6.1	95.2	135.3	6.1	95.5	130.4	5.9	95.9
SS	246.0	0.1	100	240.0	0.1	100	236.0	0.1	100	245.0	0.1	100
TN	41.533	4.816	88.4	42.716	5.153	87.9	45.504	5.270	88.4	41.661	5.146	87.6
TP	3.950	0.185	95.3	4.214	0.289	93.1	4.354	0.310	92.9	4.089	0.262	93.6
Total coliform count (pcs / ml)	TNTC	<30	-	TNTC	<30	-	TNTC	<30	-	TNTC	<30	-

In Comparative Example 2, the pH of the pH adjusting tank is the same because it is operated by increasing the blowing amount in order to be the same as Comparative Example 1 without the blocking plate, but in FIG. As shown in the figure, air bubbles are aggregated to trap air bubbles and become inefficient. Also, sludge is deposited on the upper part of the blocking plate and turns black so that it becomes anaerobic and releases total phosphorus (TP), increasing the concentration of total phosphorus.

In the case of Comparative Examples 2 to 4, sludge was deposited on the blocking plate to turn black and anaerobic to release total phosphorus (T-P), thereby increasing the concentration of total phosphorus.

Table 4

division	Example 1			Example 2			Comparative Example 5
	Influent (mg / ℓ)	Treated water (mg / l)	Processing efficiency (%)	Influent (mg / ℓ)	Treated water (mg / l)	Processing efficiency (%)	Influent (mg / ℓ)	Treated water (mg / l)	Processing efficiency (%)
BOD	165.0	1.8	98.9	171.6	1.4	99.2	160.9	2.0	98.8
COD	126.0	5.5	95.6	140.5	6.2	95.6	134.9	6.1	95.5
SS	223.0	5.5	97.5	241.0	0.1	100	230.0	0.1	100
TN	38.718	5.204	86.6	44.653	5.346	88.0	40.520	5.884	85.5
TP	3.844	0.179	95.3	4.154	0.148	96.4	3.984	1.245	68.8
Total coliform count (pcs / ml)	TNTC	<30	-	TNTC	<30	-	TNTC	<30	-

In Examples 1 and 2, although the blocking plate was installed in the same manner as in Comparative Example 4, air bubble holes were formed in the blocking plate, so that the total phosphorus content did not increase. In addition, in the case of Comparative Example 5, as in Example 1, even though the blocking plate formed with air bubbles was installed, unlike in Example 1, microbubbles were supplied, and as shown in Table 2, the dissolved oxygen concentration of the pH control tank was increased and the microbubbles were increased. It is estimated that the alkaline sludge rises to the upper part of the pH control tank, so that the combined reaction between the di-trivalent cation and the insoluble salt of PO4-P by alkaline sludge does not occur. That is, the same general processing result as that of the other MBR method is conventionally shown.

In the case of Comparative Example 3 is less than Comparative Example 2 by placing the inclination on the blocking plate, but also the space trapped in the air as shown by the large circle of Figure 3b occurs, in particular due to the inclination of the blocking plate Sludge buildup in the upper part is much more severe than in Comparative Example 2, which leads to a marked increase in sludge injuries and an increase in total phosphorus concentration.

In addition, in Comparative Example 4, as shown in Fig. 3c, the side of the pH control tank was penetrated to supplement the air trapping region, but sludge anaerobic and total phosphorus concentration increase due to sludge deposition still occur.

On the contrary, in Example 1, the air trapping area is not formed as shown in FIG. 4A, and the sludge is deposited on the upper part by providing air holes in the blocking plate, so that the pH of the pH control tank can be adjusted even with a small amount of airflow. The total phosphorus concentration can be lowered to the target level.

Furthermore, the second embodiment is similar to the first embodiment, but by adding the effect of the sludge hitting the blocking plate as well as the role of scraping the sludge adjacent to the blocking plate by moving the air by pleating the bottom of the blocking plate as shown in Figure 5a. By further stimulating the pH, you can adjust the pH more efficiently than before even with a small air flow.

Experimental Example 2

The pH, dissolved oxygen, blowing amount and power amount of the pH adjusting tanks of the Examples and Comparative Examples were measured and shown in Table 5.

Table 5

division	Comparative Example 1	Comparative Example 2	Comparative Example 3	Comparative Example 4	Example 1	Example 2	Comparative Example 5
pH	7.07	7.06	7.06	7.07	7.06	7.08	6.46
Dissolved Oxygen (mg / l)	2.1	1.8	1.8	1.7	1.7	1.5	3.4
Air flow rate (L / min)	8.0	6.4	6.3	6.3	4.9	3.8	2.1
Power amount (Wh)	192	148	146	145	116	92	49

In the above examples and comparative examples, the dissolved oxygen amount and the blowing amount and the power amount when the pH of the pH control tank was adjusted to 7.05 by varying the blowing amount, the blowing amount and the power amount is constant in the total blowing amount and power amount supplied to the pH control tank and the membrane tank Except for the blowing amount and the power amount of the separation membrane tank, it is calculated only the blowing amount and the power scheme used for the pH control of the pH control tank.

Examples 1 and 2 were able to achieve the target pH while significantly reducing the air flow amount and the amount of power according to the comparative examples 1 to 4. However, in the case of Comparative Example 5, even though the air flow was increased to adjust the pH to 7.05 level, the alkali sludge in the pH control tank was floated by the microbubbles in the form of scum, which was oxidized with time and the pH was lowered to achieve the target pH. It was impossible to do, and at the same time it was confirmed that only dissolved oxygen concentration was increased compared to Examples 1 and 2.

[Description of the code]

100: bioreactor 110: anoxic tank

120: pH control tank 121: air bubble supply device

122a, 122b, 122c, 122d: blocking plate

1220a, 1220b, 1220c, 1220d: Bubble Hole

1221a, 1221b, 1221c, 1221d: wrinkles

130: separation membrane

140: treated water tank 200: alkali sludge tank

a: alkali compound supply passage b: sludge supply passage

c: alkali sludge conveying passage d: activated sludge conveying passage

e: activated sludge discharge passage f: dissolved oxygen reduction activated sludge supply passage

The sewage and wastewater treatment apparatus of the present invention and the method for reducing nitrogen and phosphorus in sewage and wastewater using the same are added to the bioreactor by adding an alkali sludge containing an alkali compound mixed with activated sludge to reduce phosphorus in the sewage and wastewater. In the process of removing nitrogen and phosphorus in the process, while reducing the air volume and energy, the pH and dissolved oxygen in the pH control tank are kept the same, so that the total phosphorus and total nitrogen can be treated to 0.5 mg / l or less and 5 mg / l or less, respectively. Can be.

Claims (20)

1. Includes sewage and waste water storage tanks, biological reaction tanks and treated water tanks;

   An alkali sludge tank connected with an alkali compound supply passage and a sludge supply passage, and an alkali sludge tank for producing alkali sludge by stirring the alkali compound and sludge with an agitating device provided, and an alkali sludge for transporting the alkali sludge of the alkali sludge tank to the bioreactor. A conveying passage;

   The bioreactor is an anoxic tank for removing and denitrifying organic matter from sewage and wastewater containing nitrogen and phosphorus as inflow water, and changing the dissolved phosphorus in the sewage and wastewater introduced from the anoxic tank into insoluble phosphate to be adsorbed onto activated sludge. A pH control tank to nitrate the inflow water and the activated sludge introduced from the pH control tank, and to separate the activated sludge into a membrane and to treat water;

   The separation membrane tank in the sewage and wastewater treatment apparatus including an activated sludge return passage for conveying some of the activated sludge treated in the separation tank to an anoxic tank and an activated sludge discharge passage for discharging some of the activated sludge to the outside.

   The pH control tank is provided with an air bubble supply device having a nozzle for supplying air bubbles into the pH control tank, and a blocking plate obstructing the rise of air bubbles discharged from the air bubble supply device is inclined to the water surface,

   Sewage and wastewater treatment apparatus, characterized in that the blocking plate is formed with a plurality of holes.
2. The sewage and wastewater treatment apparatus according to claim 1, wherein the diameter of the nozzle of the air bubble supply device is 0.5 to 10 mm.
3. The sewage and wastewater treatment apparatus according to claim 2, wherein the diameter of the nozzle of the air bubble supply device is 2 to 8 mm.
4. The wastewater treatment apparatus according to claim 1, wherein the upper end of the obliquely installed blocking plate is spaced apart from the side wall of the pH adjusting tank so as to provide an upward passage of air bubbles.
5. 5. The sewage and wastewater treatment apparatus according to claim 4, wherein the lower end of the obliquely installed blocking plate is spaced apart from the side wall of the pH adjusting tank so as to provide a downward passage of alkali sludge.
6. The method of claim 5, wherein one or more separate blocking plate is further installed on the spaced upper portion of the blocking plate, and the blocking plate further installed on the upper portion to raise the air bubbles through the air rise passage formed by the blocking plate installed on the lower portion thereof. So that the air rise passage formed by the blocking plate further installed in the upper portion and the blocking plate provided in the lower portion so as to interfere, formed in different positions when viewed in the vertical direction of the bottom of the pH control tank, sewage and wastewater treatment Device.
7. 7. The sewage and wastewater treatment apparatus according to claim 6, wherein the blocking plate additionally provided at the upper part is installed in a zigzag with different inclination directions.
8. The sewage and wastewater treatment apparatus according to claim 5, wherein the hole diameter of the blocking plate is equal to or larger than the diameter of the nozzle of the air bubble supply device.
9. 9. The sewage and wastewater treatment apparatus according to claim 8, wherein the hole diameter of the blocking plate is 0.6 to 15 mm.
10. 7. The sewage and wastewater treatment apparatus according to claim 6, wherein the size of the hole of the blocking plate provided in the upper portion is greater than or equal to the size of the hole of the blocking plate provided in the lower portion.
11. 9. The sewage and wastewater treatment apparatus according to claim 8, wherein the size of the hole increases toward the inclined upper side of the blocking plate.
12. 9. The sewage and wastewater treatment apparatus according to claim 8, wherein the hole of the blocking plate is formed in an area adjacent to one end of the blocking plate in contact with the air rising passage.
13. 7. The sewage and wastewater treatment apparatus according to claim 6, wherein the holes formed in the blocking plate provided in the upper portion and the blocking plate provided in the lower portion are formed at different positions when viewed in the vertical direction of the bottom surface of the pH adjusting tank.
14. 6. The sewage and wastewater treatment apparatus according to claim 5, wherein wrinkles are formed on a lower surface of the blocking plate perpendicular to the inclination direction of the blocking plate.
15. 15. The sewage and wastewater treatment apparatus according to claim 14, wherein a depth of wrinkles deepens toward the inclined upper side of the blocking plate.
16. The sewage and wastewater treatment apparatus according to claim 5, wherein an angle between an arbitrary surface parallel to the water surface of the pH adjusting tank and a lower surface of the blocking plate is smaller than an angle between an upper surface of the blocking plate.
17. According to claim 5, Activated sludge and the tubular activated sludge retention portion which decreases in diameter from the top to the bottom outside or inside the anaerobic tank, and discharged through the active sludge conveying passage to the upper portion of the tubular active sludge retention portion and the After each of the sewage and wastewater is supplied, a mixture of activated sludge and sewage and wastewater is settled to the lower portion of the tubular activated sludge retention portion, and is supplied to the lower portion of the anoxic tank.
18. The method of claim 5, wherein the alkali compound is sodium hypochlorite (NaOCl), calcium hypochlorite (Ca (OCl) ₂ ), sodium hydroxide (NaOH), potassium hydroxide (KOH), sodium bicarbonate (NaHCO ₃ ), potassium bi Carbonate (KHCO ₃ ), magnesium hydroxide (Mg (OH) ₂ ), sodium percarbonate (2Na ₂ CO ₃ -3H ₂ O), calcium hydroxide (Ca (OH) ₂ ), calcium oxide (CaO) and magnesium Sewage and wastewater treatment apparatus, characterized in that at least one selected from the group consisting of oxide (MgO).
19. In the method for reducing nitrogen and phosphorus in sewage and wastewater, by mixing sludge and an alkali compound to produce alkali sludge, and then adding alkali sludge to a biological reaction tank including an anoxic tank, a pH adjusting tank and a separation membrane tank,

    Using the sewage and wastewater treatment apparatus of any one of claims 1 to 18,

    The sewage and wastewater treatment device supplies air bubbles through at least one blocking plate having a hole diameter of 0.6 to 15 mm and an air bubble supplying device having a diameter of 0.5 to 10 mm of nozzles, thereby adjusting the pH condition to pH 6.5 to A method for reducing nitrogen and phosphorus in sewage and wastewater, characterized in that the blowing amount is adjusted to 7.5 and dissolved oxygen 1 to 10 mg / l.
20. 20. The method of claim 19, wherein the alkaline sludge is added in an amount of 5 to 40 parts by volume based on 100 parts by weight of activated sludge containing influent of the bioreactor.

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