KR20220111890A - Wastewater treatment system using a2o - Google Patents

Abstract

The present invention relates to an A2O reactor equipped with a device for aeration, agitation and liquid transfer, and a sewage and wastewater treatment method using the same and, more specifically, to an A2O reactor equipped with a device for aeration, agitation and liquid transfer, and a sewage and wastewater treatment method using the same, wherein the A2O reactor comprises: an anaerobic tank; an anoxic tank; and an aerobic tank, and a device capable of selective aeration, agitation and liquid transfer is formed in the anoxic tank and the aerobic tank, so that aeration, agitation and liquid transfer are possible without the need for a separate pump, aeration device and agitation device, therefore operation efficiency can be increased by simplifying an equipment configuration and energy can be saved.

Description

A2O reaction system capable of efficient sludge treatment {WASTEWATER TREATMENT SYSTEM USING A2O}

The present invention is an A2O reaction system that removes nitrogen, phosphorus, organic matter and moisture from raw sewage and wastewater and separates and discharges them in the form of solids. Maximizing the removal efficiency of organic matter, nitrogen and phosphorus contained in the influent raw water by utilizing the separation membrane module configured in will be.

In general, the amount of sewage sludge generated in the treatment process is also increasing with the increase in the sewage supply rate and the amount of sewage flowing into public sewage treatment facilities.

Discharge of sewage treatment sludge to the sea is prohibited from January 1, 2012, and all sewage sludge is treated on land. Onshore treatment costs such as biogas production and power generation are increasing.

In addition, in the sludge dewatering process, inorganic coagulants such as aluminum sulfate, polyaluminum chloride, and polymer coagulants are used to separate moisture and solids, so the cost is further increased due to the increase in the amount of chemical sludge as well as the burden of chemical costs.

In addition, explosive chemicals added in the sludge treatment system not only cause problems such as whitening, scale formation, and pipe corrosion in post-treatment processes such as drying and incineration, but also some unreacted chemicals are discharged into rivers, etc. together with effluent. It adversely affects the water system.

On the other hand, in order to treat the high-concentration dewatering filtrate generated in the sludge dewatering process, it was returned to the front end of the bioreactor or a separate concentrated water treatment process was installed.

However, this is known to cause an increase in construction and maintenance costs due to an increase in the treatment capacity of the bioreactor, or to cause various problems in biological reactions.

In addition, in the current sludge concentration and dewatering process, belt press dewatering process, centrifugal dehydration process, screw type dehydration process, filter press dewatering process, etc. are generally used. All of these processes cause a lot of maintenance cost due to the use of many chemicals and power. Furthermore, the need for a sludge storage tank, a sludge concentration tank, and a dewatered filtered water storage tank increased the overall construction cost, and there were many problems in economic feasibility because the equipment cost, equipment cost, and maintenance cost were additionally added.

Lastly, the operation of the sludge separation process was difficult, requiring a large number of dedicated personnel, and frequent breakdowns resulted in a high frequency of problems.

Republic of Korea Patent Publication 10-2017-0060642

Therefore, the problem to be solved by the present invention is to adsorb only sludge solids, which are the remaining residues except for water, among sludge contained in sewage and wastewater, filter it, and discharge the filtered water to a nearby river. It is to provide an A2O reaction system that is excellent in economy, operation efficiency and energy economy, and can efficiently treat sludge.

The A2O reaction system (hereinafter referred to as the “system of the present invention”) capable of efficiently treating sludge of the present invention is an anaerobic tank into which raw water of sewage and wastewater flows, an anaerobic tank adjacent to the anaerobic tank, an aerobic tank adjacent to the anaerobic tank, and the aerobic tank In the A2O reaction system including a sedimentation tank adjacent to a sludge tank in which a sludge inlet line through which sludge is introduced from the settling tank and a sludge return line for returning the stored sludge to the anaerobic tank are formed, the sludge tank is configured and suctioned and a sludge treatment device including a separation membrane module that absorbs moisture and air from the sludge stored by pressure to the inside, discharges it to the outside, and adsorbs the solid content in the sludge.

As an example, the separation membrane module has a flow path formed therein to absorb moisture and air through the flow path from the sludge stored in the sludge tank by suction pressure, discharge it to the outside, and a plurality of separation membranes for adsorbing solid content in the sludge; A collecting port having a collecting space for collecting moisture and air is formed on the upper part of the separation membrane, and a treated water discharge line communicating with the collecting port and having a pump is formed.

As an example, the sludge return line is characterized in that it is composed of a first sludge return line formed at the upper end of the sludge tank and a second sludge return line formed at the lower end of the sludge tank.

As an example, the solid content of the sludge adsorbed to the separation membrane is desorbed by the pumping of the pump, and an excess sludge discharge line is formed at the bottom of the sludge tank so that the desorbed solid is discharged to the outside, and the excess sludge discharge line It is characterized in that the surplus sludge storage tank is further configured to store the solids discharged through.

As an example, the sludge tank further includes a laser sensor for measuring the distance between the inner periphery of the sludge tank and the deposition layer by irradiating a laser to the deposition layer formed by adsorbing solids to the outermost membrane.

As an example, in the separation membrane, the membrane filter is manufactured by a composition including cellulose acetate, silicon carbide, sodium polysulfate sodium pentosulfate, seaweed extract, and polyamide fiber.

As described in detail above, in the system of the present invention, degassing is performed by one device and the highly concentrated sludge is returned to the anaerobic tank to increase the reaction efficiency and at the same time utilize a separation membrane module to discharge excess sludge with a low moisture content compared to the prior art. have. In addition, since a separate sludge storage/concentration facility is not required, the capacity of the post-treatment facility can be reduced, which has an economic advantage in terms of facility cost reduction.

In addition, through the suction pressure of the suction pump, the sludge can be discharged directly into the nearby river through the filtrate suction pipe, which is efficient. Environmental problems can be improved by solving problems that have a good influence, and in the water treatment process, the dehydration device is installed in the middle of the transfer pipe between the bioreactors, so there is no need for a separate piping facility, and the dehydration device can be operated only by operating the automatic valve. It can be very convenient.

1 is a schematic diagram showing the system of the present invention,
2a to 2c are views showing the operating state of the sludge treatment apparatus according to one configuration of the present invention,
3 is a partial view showing the sludge treatment device,
4 is a perspective view showing a sludge treatment device,
5 is a block diagram showing the prior art.

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

The system of the present invention relates to an A20 reaction system equipped with a sludge treatment device (2). As shown in FIG. 1 , the anaerobic tank 3 in which the incoming raw water is accommodated, and the reaction liquid flowing in from the anaerobic tank 3 are accommodated. to an anoxic tank 4, an aerobic tank 5 for receiving the reaction liquid flowing in from the anaerobic tank 4, and a sedimentation tank 6 for filtering activated sludge from the treated water flowing in from the aerobic tank 5 to discharge the treated water By adding the sludge treatment device 2 to the system used for the general A20 reaction (process) configured, the sludge conveyance, sludge dehydration, and the accompanying discharge of treated water are made by one device.

In the anaerobic tank (3), phosphorus is released from the introduced sewage and wastewater, in the anoxic tank (4), nitrate nitrogen is denitrified with nitrogen gas, and in the aeration tank (5), nitrification and phosphorus are ingested so that nitrogen is oxidized as a whole. The process for removing , phosphorus and organic matter is the same as the existing A2O process.

First, the anaerobic tank 3 receives the raw water continuously or intermittently introduced, which may be determined depending on the quantity of the incoming raw water and whether a flow rate adjustment tank is installed at the front end of the anaerobic tank 3, although not shown in the drawings. In addition, the inflow point of the sewage from the sewage conduit may be the upper part of the anaerobic tank 3 , but it is natural that the height of the sewage inflow point may be different depending on the depth of the sewage pipe to be installed.

Although the anaerobic tank 3 is not shown in the drawings with the anaerobic tank 4, liquid transfer and internal transfer may be made by circulation means.

Although not shown in the drawings, the anoxic tank 4 is provided with a stirring means so that the sludge can be smoothly stirred in the anoxic tank 4 . This is to increase the chance of contact between organic matter and microorganisms based on this stirring action.

In addition, although not shown in the drawings, a circulation means is also configured between the anoxic tank 4 and the aerobic tank 5 so that liquid transfer and internal transfer can be made.

In particular, the system (1) of the present invention includes a sludge treatment device (2). The sludge treatment device (2) transfers the sludge inlet line (211) through which sludge is introduced from the settling tank (6) and the sludge to be stored. The sludge tank 21 is formed with a sludge return line 212 for returning to the anaerobic tank 3, and moisture and air are absorbed and discharged to the outside from the sludge configured in the sludge tank 21 and stored by suction pressure. and a separation membrane module 22 for adsorbing solids in the sludge.

As shown in FIGS. 3 and 4, a flow path 221-1 is formed in the separation membrane module 22, and the sludge stored in the sludge tank 21 by suction pressure passes through the flow path 221-1. A plurality of separation membranes 221 for absorbing moisture and air, discharging them to the outside, and adsorbing solids in the sludge, and a collecting port 222 having a collection space for collecting moisture and air at the upper portion of the separation membrane 221; It is characterized in that the treatment water discharge line 223 is formed in communication with the collecting port 222 and the pumps 231 and 232 are formed.

The separation membrane 221 allows a flow path 221-1 to be formed between the separation membrane filters 221-2 made of a porous material from the sludge S through the separation membrane filter 221-2 as described above. As such, it is to separate moisture and air, and, of course, to filter out foreign substances in this process. That is, the water introduced into the flow path 221-1 is filtered, and the treated water may be discharged as it is.

In addition, although reference numbers are not shown on the separation membrane 221 , frames are mounted on upper and lower portions of the separation membrane filter 221 - 2 , and the upper frame is configured to communicate with the collecting port 222 .

The sludge tank 21 is a space for storing sludge introduced through the sludge inlet line 211, and a sludge return line 212 is formed on the other side, and the sludge return line 212 is a sludge tank 21. It is characterized in that it is composed of a first sludge return line (212-1) formed at the upper end and a second sludge return line (212-2) formed at the lower end of the sludge tank (21).

In addition, the solid content (S-1) of the sludge adsorbed to the separation membrane 221 is desorbed by the pumping of the pump 232, and an excess sludge discharge line 213 is formed at the bottom of the sludge tank 21 for desorption It is characterized in that the excess sludge storage tank 24 is further configured such that the solid content (S-1) is discharged to the outside, and the solid content (S-1) discharged through the excess sludge discharge line 213 is stored.

As shown in FIGS. 2A and 2B, when the sludge introduced through the sludge inlet line 211 is filled in the sludge tank 21 and reaches a certain water level, it overflows and flows through the first sludge return line 212-1. As shown in Figure 1, the sludge is transported to the front end of the anaerobic tank (3).

Then, in the state in which the sludge tank 21 is filled, the suction pump 231 is operated to generate suction pressure in each separation membrane 221 of the separation membrane module 22, so that the sludge solid content (S-1) on the surface of the separation membrane 221 is While adsorbing, moisture and air are sucked into the separation membrane 221 and are collected in the collecting port 222 through the flow path 221-1, and the collected moisture and air are discharged to the outside through the treated water discharge line 223. to make it happen

In this way, water as well as air are separated from the sludge (S) by the suction pressure. As a result, the returned sludge is highly concentrated by the separation of moisture, and the DO is lowered by degassing, so that the reaction efficiency in the anaerobic tank (3) to be able to increase

This operation continues until the solid content (S-1) adsorbed on the surface of the separation membrane 221 is sufficiently (3 to 5 mm) adsorbed, and then the valves of the suction pump 231 and the sludge inlet line 211 are turned off, As the valve of the second sludge return line 212-2 is turned on, the sludge S stored in the sludge tank 21 is completely emptied to be returned through the second sludge return line 212-2. Even at this time, since the suction pressure is maintained in the separation membrane 221 , the state in which the solid content S-1 is adsorbed to the surface is maintained.

Next, as shown in FIG. 2c , when the sludge S in the sludge tank 21 is completely discharged, the discharge pump 232 is operated to discharge the compressed air to each separation membrane 221 . At this time, backwash water may be injected.

In this process, the solid content (S-1) adsorbed on the surface of the separation membrane 221 is detached from the surface of the membrane and discharged to the excess sludge storage tank 24 through the excess sludge discharge line 213 . Due to this action, a very small amount of surplus sludge (1/7 compared to the existing technology) with a low moisture content (90 to 87%) is generated, and as shown in the existing technology shown in FIG. There is no need for a concentration facility, and the capacity of the post-treatment facility (dehydration) is greatly reduced, so that economic advantages can be achieved.

On the other hand, an example of controlling failure due to blockage between the separation membranes 221 by automatically detecting the adsorption of sufficient solid content (S-1) to the separation membrane 221 and automatically performing the above-mentioned desorption process is shown in FIG. 4 is shown in

In FIG. 4, the sludge tank 21 is irradiated with a laser to the deposition layer formed by adsorbing the solid content (S-1) to the outermost separation membrane 221 to measure the distance between the inner periphery of the sludge tank 21 and the deposition layer. It presents an example in which the laser sensor 214 is further included. Here, since the laser sensor 214 may be a known sensor, a detailed description thereof will be omitted.

A communication unit is configured in the laser sensor 214, and when it is detected that the distance of the deposition layer is greater than or equal to a threshold, a signal is transmitted to the control unit, although not shown in the drawing, and the control unit controls the above-mentioned detachment process accordingly. is to let it go

On the other hand, the separation membrane 221 may be exposed to fatigue due to tension due to repeated operation of the suction pump 231 and the discharge pump 232 , and this fatigue may cause cracks in the separation membrane filter 221-2. Foreign substances are deposited in these cracks, and deterioration due to corrosion may be induced by the deposited foreign substances.

Accordingly, in the present invention, in the separator 221, the separator filter 221-2 is prepared by using a composition including cellulose acetate, silicon carbide, sodium polysulfate pentosulfate, seaweed extract, and polyamide fiber.

Cellulose acetate is a hydrophilic polymer, and has an active interaction with water molecules due to hydrogen bonding, etc.

However, cellulose acetate is sensitive to heat or chemicals, and there may be a problem in that the polymer chain is easily separated by enzymes contained in the sludge and the membrane is destroyed.

Accordingly, silicon carbide is further added to the composition, and silicon carbide also exhibits hydrophilicity, so water permeability is high, and it is strong against heat or chemicals and has excellent durability.

The silicon carbide is very hard and clean, and decomposes at 2500° C. or higher into a crystalline compound of silicon and carbon. It has high high-temperature strength and excellent properties such as abrasion resistance, oxidation resistance, corrosion resistance, and crack resistance. to maintain stability.

The sodium pentosulfate polysulfate improves the resistance to cracking due to evaporation of the solvent during the curing process, and when oxidizing bacteria and sulfur-oxidizing bacteria contained in the sludge proliferate, there is a problem that may cause deterioration and corrosion of the paste. However, the sodium polysulfate is to inhibit the growth of the oxidizing bacteria and sulfate bacteria to prevent deterioration and corrosion, thereby improving durability.

The seaweed extract is to be added as a thickener while simultaneously exhibiting an antibacterial effect. That is, by inhibiting the growth of bacteria and preventing deterioration and corrosion as mentioned above, the durability is improved.

Preferably, green tea extract can be applied. Green tea contains various kinds of minerals and is a salty plant. It is a salt-tolerant plant that grows near tidal flats and salt fields and is known to exhibit antibacterial effects.

The polyamide fibers are hydrophilic and have strong toughness to improve crack resistance through crosslinking. That is, to improve resistance to fatigue due to tension.

Meanwhile, in the following, a description will be given of the sewage and wastewater treatment method using the system of the present invention. First, raw water is continuously or intermittently introduced into the anaerobic tank 3, and in the anaerobic tank 3 in which the anaerobic environment is maintained, the incoming raw water The reaction induces phosphorus release and organic matter is removed.

Next, the reaction solution of the anaerobic tank 3 is introduced into the anaerobic tank 4, and organic substances contained in the sewage and wastewater are introduced in stages from the anaerobic tank 3 to denitrify the nitrate nitrogen in the sewage and wastewater (NO3 → N2). ) will be done.

In addition, optionally, the treated water of the anaerobic tank 4 is returned to the anaerobic tank 3 as needed, and in the anaerobic tank 3, the organic matter returned from the anaerobic tank 4 through the absorption of VFAs of the phosphorus removal microorganisms Phosphorus emission will occur.

Next, the reaction solution in the anoxic tank 4 is transferred to the aerobic tank 5 and aeration is performed. Organic matter is decomposed in the aerobic tank 5 by the aeration action of the aeration device, and phosphorus absorption by the phosphorus removal microorganism occurs in nitrification (NH3 → NO3) and phosphorus released by the anaerobic reaction.

Finally, the settling tank 6 filters the activated sludge from the treated water introduced from the aerobic tank 5 so that the treated water is discharged, and the filtered activated sludge is returned to the anaerobic tank 3 using the sludge treatment device 2 . However, as mentioned above, the returned sludge is highly concentrated, and in a state in which degassing is made, the reaction is made more efficiently in the above-mentioned anaerobic tank 3 . As mentioned above, the sludge treatment device 2 is to dehydrate the sludge and discharge the treated water accompanying it at the same time as the sludge is transported.

Those skilled in the art from the above description will be aware that various changes and modifications are possible without departing from the technical spirit of the present invention. Accordingly, the technical scope of the present invention should be defined by the claims rather than being limited to the contents described in the detailed description of the specification.

2: sludge treatment device 3: anaerobic tank
4: anoxic tank 5: aerobic tank
6: sedimentation tank 21: sludge tank
211: sludge inlet line 212: sludge return line

Claims (6)

In the A2O reaction system comprising an anaerobic tank into which raw water of sewage and wastewater flows, an anoxic tank adjacent to the anaerobic tank, an aerobic tank adjacent to the anaerobic tank, and a sedimentation tank adjacent to the aerobic tank,
A sludge tank in which a sludge inlet line through which sludge is introduced from the settling tank and a sludge return line for returning the stored sludge to the anaerobic tank are formed; a sludge treatment device including a separation membrane module for discharging to the outside and adsorbing solids in the sludge;
A 2 O reaction system capable of efficient treatment of sludge, characterized in that it comprises a.
The method of claim 1,
A plurality of separation membranes are formed inside the separation membrane module to absorb moisture and air from the sludge stored in the sludge tank by suction pressure through the flow path, discharge to the outside, and adsorb solid content in the sludge; An A2O reaction system capable of efficiently treating sludge, characterized in that a collecting port having a collecting space for collecting moisture and air is formed, and a treated water discharge line communicating with the collecting port and having a pump formed therein.
The method of claim 1,
The sludge return line is an A2O reaction system capable of efficiently treating sludge, characterized in that it consists of a first sludge return line formed at the top of the sludge tank and a second sludge return line formed at the bottom of the sludge tank.
3. The method of claim 2,
The solid content of the sludge adsorbed to the separation membrane is desorbed by the pumping of the pump, and an excess sludge discharge line is formed at the lower end of the sludge tank so that the desorbed solid is discharged to the outside, and is discharged through the excess sludge discharge line A2O reaction system capable of efficient treatment of sludge, characterized in that the surplus sludge storage tank in which the solid content is stored is further configured.
5. The method of claim 4,
Efficient treatment of sludge, characterized in that the sludge tank further includes a laser sensor for measuring the distance between the inner periphery of the sludge tank and the deposition layer by irradiating a laser to the deposition layer formed by adsorbing solids to the outermost separation membrane. A2O reaction system.
3. The method of claim 2,
In the separation membrane, the separation membrane filter is an A2O reaction system capable of efficiently treating sludge, characterized in that it is manufactured by a composition containing cellulose acetate, silicon carbide, sodium polysulfate sodium pentosulfate, seaweed extract, and polyamide fiber.

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