KR20000055709A - A sewage treatment system comprising a single reaction tank and a sewage treatment method thereby - Google Patents

Abstract

PURPOSE: Wastewater treatment equipment is provided which is constructed as one reactor to maximize purification effect by bacteria in a sedimentation tank and prevent anaerobic decomposition. CONSTITUTION: A wastewater treatment method built in one reactor comprises the steps of: (i) a first step which flows the pre-treated wastewater into a certain space of an aerobic zone and aerates wastewater by diffused air spouted from the lower part; and (ii) a second step which presses and transfers the aerated wastewater to wash and flow sludge which are precipitated in the floor of the aerobic zone and around a hopper wherein the lower part in the aerobic zone is opened as a hopper type.

Description

A sewage treatment system comprising a single reaction tank and a sewage treatment method

The present invention relates to a wastewater treatment apparatus composed of a single reaction tank, and more particularly, by installing a hopper-type sedimentation tank having an open bottom in the aeration tank so that the sludge in the sedimentation tank flows into the aeration tank by gravity, and the aeration tank mixed solution is settled in the aeration tank. By intermittently spraying through a plurality of nozzles protruding from the lower edge and the center of the washing column mounted therein, all sludge deposited at the hopper portion of the settling tank is returned to the aeration tank, and the sludge deposited at the bottom of the aeration tank at the bottom of the settling tank is disturbed. By mixing with the mixed liquid in the aeration tank to prevent sludge from floating in the sedimentation tank, it is possible to effectively separate the treated water and sludge in the sedimentation tank, and to maximize the purification effect by the microorganisms in the aeration tank and to prevent anaerobic decomposition Of wastewater treatment systems The.

Conventional biological treatment methods for wastewater include screen, sedimentation tank, flow control tank, aeration tank, sedimentation tank, sludge thickening tank, and sludge treatment facility in a continuous unit process to remove debris from the screen, and then remove sand and soil having a high specific gravity from the sedimentation tank. After removing and then uniformly adjusting the concentration and amount of waste water in the flow adjusting tank to introduce a certain amount of organic pollutants into the aeration tank, purifying the waste water using microorganisms in the aeration tank, and then generating the activated sludge in the settling tank. Silver was discharged and the sludge was treated separately.

That is, the wastewater introduced into the aeration tank is removed by converting it into carbon dioxide gas and water by using the metabolism of microorganisms, and the sludge in which organic pollutants are converted into microbial cells by microbial cell synthesis is treated in solid sludge and liquid treated water in the settling tank. After solid-liquid separation, the liquid treatment water is discharged and the solid sludge is concentrated in a sludge thickening tank, and then the sludge cake is treated separately using a sludge treatment device, and the organic contaminants contained in the liquid desorption liquid are transferred to a flow adjusting tank. The waste water was purified by returning.

This general wastewater treatment process is expensive to install the facility, and it takes a lot of energy cost to transport the wastewater according to the sludge return and unit process, and also requires high technology for the maintenance and management of sludge return. There are many economic and technical difficulties in dealing with small-scale wastewater, which have led to difficulties in water conservation.

Therefore, in recent years, small and medium-sized wastewater treatment facilities have been spreading biofilm methods or fluid carriers immersed in carriers that can grow by attaching microorganisms to aeration tanks in order to maintain a high concentration of microorganisms without returning sludge. In recent years, biofilm filtration has been actively researched and disseminated, in which microorganisms adhere and grow and can carry out filtration.

An object of the present invention is to solve the conventional problems of transporting the activated sludge produced after purification of the waste water in the aeration tank to the sedimentation tank or returned from the sedimentation tank to the aeration tank, and to treat high and medium-sized wastewater including livestock wastewater. In the aeration tank, a sedimentation tank having an open lower portion is installed so that sludge in the sedimentation tank is naturally and forcedly dropped into the aeration tank, so that the treated water and sludge can be efficiently separated, and the aeration tank activated sludge does not need to be transferred to an external sedimentation tank. It is to provide a biological waste water treatment apparatus composed of a reaction tank.

Another object of the present invention is to minimize the power required for the transfer and conveyance of activated sludge, significantly reducing the maintenance costs, such as power costs, chemical costs, labor costs, installation cost is also significantly reduced to a single reactor, a single reactor It is to provide a configured biological wastewater treatment apparatus.

1 is a schematic view of the wastewater treatment apparatus of the present invention,

2 is a plan view of the apparatus.

<Explanation of symbols for main parts of drawing>

1: Waste water inlet 1 ': Aeration tank mixed liquid outlet

1 ": mixed liquid feed port 4: sludge cleaning column

5, 6: sludge cleaning side nozzle 7: sludge cleaning center nozzle

13 mixed liquid inlet 9 transfer line

10: diffuser of aeration tank 11: treated water outlet

12: sludge cleaning pump 20: aeration tank

30: sedimentation tank

An object of the present invention is a hopper-type sedimentation tank is installed in the bottom of the aeration tank of a predetermined space is installed inside the sedimentation tank is equipped with a washing column including a plurality of nozzles, the upper side of the washing column and the aeration tank one side of the aeration tank mixed liquid transfer Achieved by a single reactor connected by lines. According to the single reaction tank according to the present invention, the sedimentation sludge formed in the sedimentation tank naturally flows into the aeration tank by gravity, and the aeration tank mixed liquid is pressurized and transferred to a plurality of nozzles through the top of the washing column mounted inside the sedimentation tank, and The sludge deposited intermittently on the bottom of the aeration tank at the bottom of the sedimentation tank and the sludge deposited on the bottom of the hopper and the aeration tank is transferred to the aeration tank, whereby the sedimentation tank can effectively separate the treated water and the sludge.

Embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited thereto.

(Example)

1 is a schematic view of a wastewater treatment apparatus composed of a single reaction tank having a sedimentation tank installed in an aeration tank of the present invention, and FIG. 2 is a plan view of the sedimentation tank and aeration tank of the apparatus.

The single reaction tank according to the present invention has a wastewater inlet (1) and an aeration tank mixture liquid outlet (1 ') and a sludge cleaning mixture liquid delivery port (1 ") on the upper side of the aeration tank mixture liquid outlet (1'), respectively. The aeration tank 20 in a predetermined space in which a plurality of diffusers 10 are installed, and a plurality of nozzles 5, 6, and 7 in the lower part, and a cleaning mixture inlet 13 in the upper part are formed and closed with the outside. The sludge cleaning column 4 is mounted therein and has a treated water outlet 11 on one side thereof, the lower portion of which is opened in a flat shape, and the settling tank 30 and the mixed liquid transfer port of a predetermined space installed inside the aeration tank 20. (1 ") and the cleaning transfer line 9 including the pump 12 which connects between the mixed liquid inlet 13 of the upper end of the said washing column 4.

According to the configuration according to the present invention, if the aeration is made just below the bottom open hopper-type sedimentation tank 30, bubbles and aeration tank mixed liquid rises into the settling tank 30 through the open portion of the lower settling tank to disturb the sedimentation tank to precipitate Since the solid-liquid separation is not effectively performed, a plurality of diffusers 10 installed at the lower edge of the aeration tank are installed to maintain a constant horizontal distance from the hopper bottom of the settling tank as shown in FIG. 2. The lower edge of the aeration tank 20 preferably has an inclination angle for preventing deposition of the settling sludge.

In the hopper-type sedimentation tank, the hopper form is advantageous in the natural flow of sedimentation sludge formed in the sedimentation tank, and the gradient around the hopper is preferably 130 ° to 170 ° inward from the vertical side of the sedimentation tank.

In addition, the sludge cleaning column 4 is sprayed through the aeration tank mixed liquid introduced through the transfer line (9) through a plurality of nozzles (5, 6, 7) in the lower portion of the hopper and the bottom of the settling tank to the aeration tank. The plurality of nozzles are configured to be forcibly conveyed, and the plurality of nozzles have four to sixteen side nozzles and one central nozzle perpendicular to the lower center of the column at an angle of 120 ° to 160 ° from the vertical side of the sludge cleaning column. It is preferable that it consists of. The pump 12 in the present invention is a known pump that can be operated intermittently. The wastewater treatment step using a single reactor having the above configuration will be described for each component.

1) Aeration tank

The pretreated wastewater was introduced into the aeration tank 20 through the wastewater inlet 1 using a screen or the like. The aeration tank 10 was used to aeration such that the dissolved oxygen concentration in the aeration tank was 2 to 3 mg / L or more, and the suspended solids concentration of the mixed solution was maintained at 3,000 to 6,000 mg / L.

The hydraulic residence time in the aeration tank was 16 hours to 35 days depending on the concentration of the influent BOD, and the BOD volume load was 0.15 to 0.45 BOD-kg / ㎥ · day, and the ratio of the BOD load and the microbial amount in the aeration tank was 0.03 to 0.05 BOD. Waste water was introduced to operate at -kg / SS-kg.day. On the other hand, the aeration tank mixed liquid flows out of the mixed liquid feed port 1 "and flows into the mixed liquid inlet 13 above the sludge cleaning column 4 through the transfer line 9 to which the sludge cleaning pump 12 is attached.

2) sedimentation tank

In the sedimentation tank space outside the sludge washing column, the solid solution is separated into sludge and treated water, and the treated water is discharged to the outside through the treated water outlet 11 and the sludge is precipitated into the aeration tank 2 through the lower part of the sedimentation tank by gravity. . Some of the sediment sludge flowing down is deposited on the hopper portion, and the precipitated sludge deposited on the hopper portion is forcedly transferred to the aeration tank by using the multiple nozzles of the sludge cleaning column which will be described below.

3) Sludge Cleaning Column

The sludge deposited on the hopper was dropped into the aeration tank by spraying the aeration tank mixture liquid for about 1 to 5 minutes each time 2 to 8 times a day through the nozzles 5 and 6 formed at the lower edge of the sludge cleaning column. The aeration tank mixture was also sprayed through the central nozzle 7 formed in the lower center so that the sludge flowed down in the tank was completely mixed with the aeration tank mixture. The intermittent injection is in conjunction with the intermittent operation of the pump 12.

When the concentration of the aeration tank mixed liquid is 6,000 mg / L or more through the above-described treatment process, the aeration tank mixed liquid is discharged through the aeration tank mixed liquid conveying port 1 ', and the aeration tank mixed liquid processing apparatus and method are known. That is, the aeration tank mixed liquid treatment valve 18 is opened to transfer the mixed liquid of the above concentration to the sand filtration phase, wherein the sand filtration phase is filled with sand having an effective diameter of 0.5 to 1.2 mm or more by 600 mm or more, and the filtration speed is 4 m / hour. It is preferable that it is a sand filtration layer in which more than 30 cm of gravel supporting the sand layer is stacked thereon. Since the filtrate of the sand filtration is the same as the quality of the treatment liquid of the sedimentation tank, it is discharged as it is, and the sludge caught may be dried and composted. In consideration of the effective capacity of the aeration tank, the operation was continued after discharged so that the concentration of the aeration tank liquid mixture was about 3,000 to 4,000 mg / L.

According to the present invention, the aeration tank mixed liquid introduced through the transfer line is formed using a plurality of side nozzles (5, 6) and a central nozzle (7) formed in the sludge cleaning column (4) below the settling tank hopper and the aeration tank at the bottom of the settling tank By spraying on the bottom, sedimentation is made smoothly without disturbing sludge in the sedimentation tank, and solid-liquid separation in sedimentation tank is easy.

In addition, it is possible to reduce the power cost required for transporting the waste water from the aeration tank to the external settling tank, and additionally save the power cost because there is no return of sludge which is essential in the standard activated sludge method. In addition, it is possible to solve the maintenance technical difficulties due to the return of the sludge, there is no difficulty in maintenance even if there is no expertise in treating wastewater.

In particular, since the sedimentation tank is installed in the aeration tank, it is possible to minimize the land area required for installing the wastewater treatment system and to reduce the economic burden during installation, which is very economical and effective when installed in the medium and small-sized wastewater discharge source. In the case of small and medium-sized livestock farms that discharge high concentrations of livestock wastewater, the sludge collected on sand filtration can be collected and composted to treat wastewater in terms of wastewater purification and resource recycling.

On the other hand, when treating wastewater using this device, if aeration is intermittently instead of continuously aeration, the aeration tank maintains aerobic, anaerobic, and anaerobic conditions to remove nitrogen, which can be used as an advanced treatment method. It can also contribute greatly to the prevention of eutrophication.

Claims (10)

Aeration of the waste water by the pre-treated waste water flow into the aeration tank in a predetermined space by the diffuser ejected from the bottom, and the hopper portion of the sedimentation tank in which the lower portion installed in the aeration tank is opened in the hopper type by pressurizing the aerated waste water and A single reactor wastewater treatment method comprising the step of washing and dripping sludge deposited on the bottom of the aeration tank. The method of claim 1, wherein the acid from the bottom is discharged from a constant horizontal distance in the hopper bottom of the settling tank. The method of claim 1, wherein the pressurized feed of the aerated waste water is intermittently made. The method of claim 3, wherein the intermittent pressurization is performed about 2 to 8 times per day for about 1 to 5 minutes. The waste water inlet 1 and the aeration tank mixed liquor outlet 1 'and the cleaning mixture conveying port 1 "are respectively provided on the upper side, and a plurality of diffusers 10 are installed on the bottom. Aeration tank 20 of the space, a plurality of nozzles (5, 6, 7) in the lower portion and a mixed liquid inlet (13) is formed in the upper portion and the outer space and the washing column (4) sealed in the interior and one side It has a treated water outlet 11 and the lower portion is opened in a hopper type and connects the settling tank 30 and the mixed liquid feed port (1 ") and the mixed liquid inlet 13 pipe of a predetermined space installed inside the aeration tank 20. And a transfer pump (9) comprising a transfer pump (12). 6. A single reactor wastewater treatment apparatus according to claim 5, characterized in that the aeration tank mixed liquor outlet (1 ') is connected to a sand filtration bed by a valve (18) control. 6. The nozzle according to claim 5, wherein the plurality of nozzles are perpendicular to 4 to 16 side nozzles and a lower center portion of the cleaning column (4) at an angle of 120 ° to 160 ° outward from the vertical side of the cleaning column (4). A single reactor wastewater treatment apparatus, characterized in that consisting of a single central nozzle. According to claim 5, wherein the lower part of the settling tank (30) is characterized in that the open hopper shape formed in 130 ° to 170 ° inward from the vertical side of the settling tank, single reactor waste water treatment apparatus. The apparatus of claim 5, wherein the plurality of diffusers (10) are installed at a constant horizontal distance from the bottom of the aeration tank at the bottom of the settling hopper type. The apparatus of claim 5, wherein the lower edge of the aeration tank has an inclination angle.