KR102143397B1 - Method of processing concentrated water produced in discharge water recycling process of sewage or wastewater treatment plant and system employing the same - Google Patents

Abstract

The present invention relates to a method for processing concentrated water of a sewage or wastewater treatment plant to minimize the discharge amount of concentrated water. According to the present invention, the method comprises: a recycling process applying a reverse osmosis method to first processed water acquired by processing raw water of a sewage or wastewater treatment plant for discharge to acquire recycled water and first concentrated water; a deionization process of applying an electric accumulation-type desalting or reverse electrodialysis method to the first concentrated water acquired through the recycling process to separate ions to acquire second concentrated water and second processed water to be used as the recycling water; a biological process of dissolving organic materials included in the second concentrated water acquired through the deionization process by microorganisms to remove the same; and an active charcoal adsorption process of removing harmful matter existing in third processed water acquired through the biological process by adsorption of active charcoal.

Description

The method of processing concentrated water produced in discharge water recycling process of sewage or wastewater treatment plant and system employing the same}

The present invention relates to a method for treating concentrated water generated in a process of recycling effluent water in a sewage or wastewater treatment plant, and a system using the same, and more particularly, to a sewage or wastewater treatment plant using concentrated water generated in the effluent reuse process of a sewage or wastewater treatment plant. The present invention relates to a method of treating concentrated water generated in a sewage or wastewater reuse process in a wastewater treatment plant that is treated so that the amount of concentrated water discharge is minimized without reflux, and a system using the same.

In order to reuse the discharged water from a sewage or wastewater treatment plant, there must be a customer in a nearby area to use the reused water, and it must be able to satisfy the demanded water quality of the customer, but most of the demanders require water quality at the level of industrial water.

In order to make the effluent of large-scale facilities such as sewage or wastewater treatment plants at the level of industrial water, the reverse osmosis (RO) technique is mostly used, but the RO technique is a separation technique, not a treatment technique, and must be 25 to 30% concentrated water. Because it is generated, measures to treat this concentrated water are required.

Currently, most sewage or wastewater treatment plants follow the effluent reuse process as shown in FIG. 1. At this time, a certain portion of the concentrated water generated in the sewage or wastewater recycling process is mixed with raw water from the sewage or wastewater treatment plant and reprocessed, and then some are discharged and some are re-inputted as raw water in the recycling process. Another part of the concentrated water generated is discharged after satisfying the emission limit standard through a biological treatment process.

However, when a part of the concentrated water is mixed with raw water at a sewage or wastewater treatment plant subjected to the biological treatment process, the BOD components contained in the concentrated water, nitrogen and the like are processed, Ca ^{2 +,} and a divalent ion such as Mg ²⁺ Monovalent ions such as K ⁺ , Na ⁺ , and Cl ^- cannot be removed in the biological treatment process and remain mostly as they are.

Therefore, when the concentrated water of the reuse process is treated in the same series, ions are not discharged out of the system, and monovalent and divalent ions are continuously concentrated and the concentration increases, and the concentrated monovalent ions continue to increase the osmotic phenomenon. The concentrated divalent ions form scale on the surface of the membrane, causing fatal damage to the membrane used in reverse osmosis (RO) techniques.

In addition, in order to treat the entire amount of concentrated water generated by a biological treatment process, the amount of concentrated water is very large, about 25% compared to the raw water, and thus a large treatment cost and site are required.

However, domestic and international interest in the Zero Liquid Discharge (ZLD) process is increasing more and more due to the lack of fresh water and the changing public perception of environmental protection. In particular, as perfluorinated compounds, which are environmental hormone substances, are recently detected in tap water, there is a growing demand for a ZLD process to reuse the entire amount of effluent discharged from sewage or wastewater treatment plants to rivers without discharge.

The following are the items that must be addressed in order to implement the process of recycling effluent from a sewage or wastewater treatment plant as a ZLD process.

First, the production cost of reused water produced by the ZLD process should be more economical than the production cost of industrial water. Second, an economical optimal treatment technology for concentrated water that can minimize the amount of concentrated water must be secured. Since the accumulation of ions in the reflow treatment causes serious problems not only in the biological treatment but also in the reverse osmosis (RO) reuse process, a new optimal process technology to replace the reflow treatment of concentrated water is secured.

Since it may take some time to reach the current complete ZLD process, it is necessary to minimize the amount of discharged without returning the concentrated water generated in the reuse process to the sewage or wastewater treatment plant prior to this.

KR 10-2016-0009241 A KR 10-0953085 B1 KR 10-2012-0138967 A KR 10-1881463 B1 KR 10-1669361 B1

It is an object of the present invention conceived to solve the above problems, by applying a deionization process to remove ions from the concentrated water generated in the effluent reuse process of sewage or wastewater treatment plants to utilize the concentrated water as recycled water. To provide a method for treating concentrated water in a sewage or wastewater treatment plant and a system using the same so that the amount of concentrated water discharged is minimized without returning to the sewage or wastewater treatment plant.

The above object is achieved by the following configuration provided in the present invention.

The method for treating concentrated water generated in the process of recycling effluent water in a sewage or wastewater treatment plant according to the present invention,

A reuse treatment process in which recycled water and first concentrated water are obtained by applying a reverse osmosis technique to the first treated water obtained by treating raw water from a wastewater treatment plant for discharge;

Deionization process of separating ions by applying a capacitive desalting technique or reverse electrodialysis (EDR) to the first concentrated water obtained through the reuse treatment process to obtain the second concentrated water and the second treated water to be used as reused water ;

A biological treatment process in which organic matter contained in the second concentrated water obtained through the deionization process is decomposed and removed by microorganisms; And

An activated carbon adsorption process of removing harmful substances present in the third treated water obtained through the biological treatment process by adsorption of activated carbon,
The biological treatment process,
A circulation pump for forced circulation of wastewater stored in the aeration tank through a circulation supply pipe; It is arranged to be in communication with the circulation supply pipe, and is made through a biological treatment unit including a water jet reaction unit that ejects wastewater circulating and supplied along the circulation supply pipe and an aeration mixed with external air downward into the aeration tank,
The water jet reaction unit,
One or more wastewater discharge pipes disposed upright in the aeration tank so as to communicate with the circulation supply pipe, and having a shaft pipe nozzle forming a reduced pressure state by a shaft pipe at a lower end thereof;
One or more air supply pipes for introducing air into the shaft pipe nozzle in which depressurization is formed by a pressure difference between the atmosphere and the shaft pipe nozzle by internally installing an air supply end in the shaft pipe nozzle of the wastewater discharge pipe; And
The upper end is installed with the outer wall of the shaft pipe nozzle to form a waterjet reaction chamber, and the aeration water mixed with the wastewater discharged through the shaft pipe nozzle and the air supplied into the shaft pipe nozzle through the supply pipe through decompression is blown downward into the aeration tank. Including a mixing spout tube to,
A diffusion plate is disposed under the mixing and ejection pipe, and a plurality of permeable holes are formed in the diffusion plate, so that some of the mixed and discharged aerated water is discharged downward through the permeable hole, and the remaining aerated water is diffused outward through the diffusion plate. Is mixed into the wastewater stored in the aeration tank,
The diffusion plate is arranged in a lifting structure through a lifting guide at the end of the mixing spout pipe, and is elastically pulled upward by a traction spring, and the number of aeration discharged while elastically ascending and descending according to the aeration amount and pressure ejected through the mixing spout pipe It characterized in that it is configured to diffuse.

Preferably, the capacitive desalting technique may be a membrane capacitive desalting technique in which a membrane of cations and anions is added.

Preferably, the biological treatment process may be performed on mixed water obtained by mixing raw water of a wastewater treatment plant with second concentrated water obtained through a deionization process.

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In addition, the wastewater treatment system according to the present invention,

A wastewater treatment unit that treats raw water from a sewage treatment plant for discharge, a reuse treatment unit that obtains reused water and first concentrated water by applying a reverse osmosis technique to the first treated water provided from the sewage treatment unit, and the first concentrated water. In a wastewater treatment system comprising a concentrated water treatment module to treat,

The concentrated water treatment module

A deionization unit for separating ions by applying a capacitive desalination technique or reverse electrodialysis to the first concentrated water obtained from the reuse treatment unit to obtain second concentrated water and second treated water to be used as reused water;

A biological treatment unit that decomposes and removes organic matter contained in the second concentrated water obtained by the deionization unit; And

An activated carbon adsorption unit for removing harmful substances present in the third treated water obtained from the biological treatment unit by adsorption of activated carbon,
The biological treatment unit,
A circulation pump for forced circulation of wastewater stored in the aeration tank through a circulation supply pipe; It is disposed in communication with the circulation supply pipe, and comprises a water jet reaction unit for ejecting the wastewater circulating and supplied along the circulation supply pipe and the aeration mixed with external air downward into the aeration tank,
The water jet reaction unit,
One or more wastewater discharge pipes disposed upright in the aeration tank so as to communicate with the circulation supply pipe, and having a shaft pipe nozzle forming a reduced pressure state by a shaft pipe at a lower end thereof;
One or more air supply pipes for introducing air into the shaft pipe nozzle in which depressurization is formed by a pressure difference between the atmosphere and the shaft pipe nozzle by internally installing an air supply end in the shaft pipe nozzle of the wastewater discharge pipe; And
The upper end is installed with the outer wall of the shaft pipe nozzle to form a waterjet reaction chamber, and the aeration water mixed with the wastewater discharged through the shaft pipe nozzle and the air supplied into the shaft pipe nozzle through the supply pipe through decompression is blown downward into the aeration tank. Including a mixing spout tube to,
A diffusion plate is disposed under the mixing and ejection pipe, and a plurality of permeable holes are formed in the diffusion plate, so that some of the mixed and discharged aerated water is discharged downward through the permeable hole, and the remaining aerated water is diffused outward through the diffusion plate. Is mixed into the wastewater stored in the aeration tank,
The diffusion plate is arranged in a lifting structure through a lifting guide at the end of the mixing spout pipe, and is elastically pulled upward by a traction spring, and the number of aeration discharged while elastically ascending and descending according to the aeration amount and pressure ejected through the mixing spout pipe It characterized in that it is configured to diffuse.

As described above, according to the present invention, the generation of concentrated water can be drastically reduced by utilizing the concentrated water as recycled water through a deionization process in which ions are removed from the concentrated water generated in the effluent recycling process of a sewage or wastewater treatment plant. .

In particular, the amount of concentrated water can be reduced by up to 90% by treating concentrated water generated in the reverse osmosis (RO) reuse process using Membrane Capacitive Deionization (mCDI). A similar effect can be achieved by using the Electrodialysis Reversal Process (EDR) instead of the membrane capacitive desalination technique.

In addition, there is an effect of minimizing the discharge amount of concentrated water without returning the concentrated water to the sewage or wastewater treatment plant.

In addition, the concentrated water remaining after treatment by the membrane capacitive demineralization method (mCDI) or reverse electrodialysis (EDR) is effective in minimizing treatment cost and required land by applying a biological treatment process using a high-efficiency air diffuser.

As well as. Concentrated water that has undergone a biological treatment process has the effect of removing and discharging harmful substances such as perfluorinated compounds that may exist in the concentrated water through the biological treatment process by treating trace harmful substances through an activated carbon adsorption process.

In particular, in the present invention, the concentrated water remaining after treatment by the membrane capacitive demineralization method (mCDI) or reverse electrodialysis (EDR) is generated at a level of 2.5% compared to the raw water, but instead of discharging through a biological treatment process and an activated carbon adsorption process. If economic feasibility is allowed, a complete zero-discharge process can be implemented through the evaporation process and crystallization process.

1 is a block diagram showing an existing wastewater treatment system,
Figure 2 is a block diagram illustrating the configuration of a wastewater treatment system proposed as a preferred embodiment in the present invention,
3 and 4 show the construction state of the biological treatment unit proposed as a preferred embodiment in the present invention,
5 shows the overall configuration of a biological treatment unit proposed as a preferred embodiment in the present invention,
6 and 7 are enlarged views showing the operating states of the'A' portion and the'B' portion in FIG. 5,
8 is a flow chart showing a method for treating concentrated water in a sewage or wastewater treatment plant proposed as a preferred embodiment in the present invention,
9 is a flow chart showing another method for treating concentrated water in a sewage or wastewater treatment plant proposed as a preferred embodiment for implementing ZLD in the present invention.

Hereinafter, a method for treating concentrated water in a sewage or wastewater treatment plant proposed as a preferred embodiment in the present invention and a system using the same will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing an existing wastewater treatment system, FIG. 2 is a block diagram illustrating the configuration of a wastewater treatment system proposed as a preferred embodiment in the present invention, and FIGS. 3 and 4 are preferred implementations in the present invention. As an example, it shows the construction state of the biological treatment unit proposed, and FIG. 5 shows the overall configuration of the biological treatment unit proposed as a preferred embodiment in the present invention, and FIGS. 6 and 7 are part'A' in FIG. And'B' is an enlarged view showing the working states, and FIG. 8 is a flow chart showing a method of treating concentrated water in a sewage or wastewater treatment plant proposed as a preferred embodiment in the present invention, and FIG. 9 is a ZLD implementation in the present invention. It is a flow chart showing another method for treating concentrated water in a sewage or wastewater treatment plant proposed as a preferred embodiment for the following.

The sewage treatment system 1 proposed as a preferred embodiment treats the effluent from the sewage or wastewater treatment plant and treats the concentrated water generated by the reuse treatment unit 30 for reuse as industrial water and returns it to the sewage treatment facility. Even so, the amount of discharge is minimized.

Sewage water treatment system 1 according to an embodiment, as shown in Figure 2, with respect to the first treated water provided from the wastewater treatment unit 10, the wastewater treatment unit 10 to treat the raw water of the wastewater treatment plant for discharge And a reuse treatment unit 30 for obtaining reused water and first concentrated water by applying a reverse osmosis technique, and a first concentrated water treatment module 50 for processing the first concentrated water. The first concentrated water treatment module 50 separates ions by applying a capacitive desalination technique or reverse electrodialysis (EDR) to the first concentrated water obtained from the reuse treatment unit 30 to be used as second concentrated water and reused water. A deionization unit 51 for obtaining the second treated water to be treated, a biological treatment unit 53 for decomposing and removing organic matter contained in the second concentrated water obtained from the deionization unit 51 by microorganisms, and a biological treatment unit 53 It includes an activated carbon adsorption unit 55 for removing harmful substances present in the third treated water obtained from by adsorption of activated carbon.

In the wastewater treatment system 1, the reuse treatment unit 30 is for generating reused water from the first treated water provided from the sewage treatment unit 10, and the first treated water of the wastewater treatment unit 10 is filtered through filtration. Reusable water can be generated through an ultra filteration (UF) technique that filters out and a reverse osmosis (RO) technique that filters ions by reverse osmosis. Regarding the reuse water generation technique, the present invention is not limited thereto, and various currently disclosed techniques can be used.

Osmosis refers to the natural movement of water molecules across a semi-permeable membrane to balance the salt concentration in both regions from a low salt concentration region to a high salt concentration region, and the force per region causing this movement is osmotic pressure. Is defined as On the other hand, in reverse osmosis (RO), an external pressure greater than the osmotic pressure is applied to the higher salinity side, which strongly draws water across the membrane to produce highly concentrated brine and water.

Ultrafiltration (UF) is a membrane separation technique that separates large solute molecules from small solute molecules or solvent molecules, and acts with reverse osmosis (RO) to produce reused water.

For example, ultrafiltration (UF) passes monovalent ions and removes divalent metal ions, and reverse osmosis (RO) removes monovalent ions, so in the case of wastewater, divalent metal ions and monovalent acid ions are removed. Because only pure water is permeated, sewage or wastewater treated water can be recycled.

The reused water obtained from the reuse treatment unit 30 may be supplied to a consumer and used. However, in the reuse treatment unit 30, the first concentrated water containing a large amount of ions filtered during the reverse osmosis (RO) process as a by-product as well as the reused water is inevitably generated, and the first concentrated water is the first concentrated water treatment module 50 Is provided as

The first concentrated water treatment module 50 is for processing the first concentrated water provided from the reuse treatment unit 30. Specifically, the deionization unit 51 removes ionic substances from the first concentrated water obtained by the reuse treatment unit 30 so that it can be used as recycled water. The reused water obtained from the deionization unit 51 may also be supplied to a customer.

Methods of separating ionic substances in the deionization unit 51 include reverse osmosis (RO) techniques, forward osmosis (FO) techniques, electrodialysis (ED) techniques, and reverse electrodialysis reverse: EDR) technique, capacitive deionization (CDI) technique, and reverse electrodialysis (EDR) technique are possible.

According to an embodiment, the deionization unit 51 employs a capacitive desalination (CDI) or reverse electrodialysis (EDR) technique. The capacitive desalination (CDI) technique uses the principle of adsorption and desorption reaction of ions by electric force in an electric double layer (EDL) formed at the interface of a charged electrode, and reverse electrodialysis (EDR). ) Is also a principle of separating cations and anions through an ion exchange membrane arranged in an alternating manner by charging electricity to the electrode, and its principle is similar to the capacitive desalination (CDI) technique.

In the case of discharged water from the sewage treatment plant, TDS (Total Dissolved Solids) is about 1,000 to 1,500 mg/L, and in the case of TDS of the first concentrated water generated in the reuse treatment unit 30 using the reverse osmosis (RO) technique, the TDS is weak. Since it is 5,000 mg/L, it can be said that the capacitive desalination (CDI) or reverse electrodialysis (EDR) technique is suitable as a technology that can reduce the concentrated water generated in the reuse treatment unit 30.

The capacitive desalination technique consists of two steps, the first is an adsorption step, in which ions of water containing ions are adsorbed and stored on an activated carbon electrode having an opposite charge when a potential is applied to the electrode, and the second is a regeneration step. When the reverse potential is applied, ions adsorbed on the activated carbon electrode are desorbed and discharged. Specifically, when a voltage is applied within a potential range (about 1 to 2 V) in which no electrode reaction occurs, a certain amount of charge is charged to the electrode. When brine water containing ions is passed through the charged electrode, in this case, the first concentrated water obtained from the reuse treatment unit 30 is passed, ions having a charge opposite to that of the charged electrode are moved to each electrode by electrostatic force and are brought to the electrode surface. Water that has been adsorbed and passed through the electrode, that is, treated water from which ions have been removed can be obtained. When the adsorption capacity of the electrode is saturated, no more ions can be adsorbed, and the ions of the influent water come out as it is. In order to regenerate the electrode by desorbing ions adsorbed on the electrode, the electrodes are short-circuited or an adsorption potential and an opposite potential are applied. In this case, the electrodes lose their charge or have opposite charges, so that the adsorbed ions are rapidly desorbed and the electrodes are regenerated.

According to another embodiment, the deionization unit 51 may apply a membrane capacitive demineralization technique (mCDI). The membrane capacitive desalination (mCDI) technique maximizes the separation efficiency by adding a membrane of positive and negative ions to the capacitive demineralization method (CDI).

In other words, the membrane capacitive desalination (mCDI) technique uses a cation exchange membrane that can selectively pass cations to the cathode and an anion exchange membrane that can selectively pass anions to the anode in the capacitive desalination (CDI) technique. Improve the efficiency of

The membrane capacitive demineralization method (mCDI) ion exchange membrane prevents adsorption of ions desorbed by the reverse potential to the counter electrode when regenerating after the electrode is saturated and adsorbed, thereby improving the efficiency of the electrode.

In other words, if there is no ion exchange membrane when the reverse potential is applied, the desorbed ions go back to the opposite electrode and attach to it.The ion exchange membrane blocks the detached ions from attaching to the opposite electrode again, so that the electrode is regenerated smoothly. Since the electrode is easily regenerated, the efficiency of the electrode can be improved.

When the first concentrated water is treated using the membrane capacitive desalination (mCDI) technique, the amount of the first concentrated water generated in the reuse treatment unit 30 using reverse osmosis (RO) can be reduced by up to 90%. .

The TDS of the first treated water entering the reuse treatment unit 30 using reverse osmosis (RO) is about 1,000 to 1,500 mg/L, and the TDS of the first concentrated water generated in the reuse treatment unit 30 is reverse osmosis (RO). For example, when the recovery rate of is 75%, it is about 3,000 to 4,000 mg/L, not exceeding 5,000 mg/L. Membrane capacitive desalination (mCDI) can also be treated sufficiently because the TDS allowed for inflow is less than 5,000 mg/L.

On the other hand, since the amount of ions adsorbed to the electrode is determined by the capacitance of the electrode used, the electrode used in the capacitive desalination technique or the membrane capacitive desalination technique is a porous carbon electrode with a large specific surface area. It is commonly used.

The advantage of the capacitive desalination technique is that it operates at a low potential where no electrode reaction occurs, so the energy consumption is very low compared to other separation techniques, and because adsorption and desorption are performed only by changing the potential of the electrode, the operation of the process is reduced. It is very simple and requires low power in the operation process, so it is possible to use alternative energy sources such as fuel cells and solar cells, and it is environmentally friendly with no secondary waste due to no use of chemical substances in the electrode regeneration process. .

In the deionization unit 51, ionic substances are removed from the first concentrated water obtained in the reuse treatment unit 30 to obtain not only the second treated water used as the reused water, but also the second concentrated water having a higher concentration.

Next, the biological treatment unit 53 is for removing organic substances contained in the second concentrated water obtained by the deionization unit 51 by decomposition by microorganisms, and as a result, the third treated water may be obtained.

According to an embodiment, the biological treatment unit 53 injects high pressure to form an aerated state to increase the amount of dissolved oxygen to decompose and remove organic matter contained in the mixed water of the raw water and the second concentrated water of the wastewater treatment plant by microorganisms. Hereinafter, for convenience of description, the mixed water obtained by mixing the second concentrated water and raw water will be referred to as wastewater. Meanwhile, the second concentrated water may be mixed with the first treated water obtained from the sewage treatment unit 10 instead of the raw water of the sewage treatment plant.

As a result of the first concentrated water treatment in the deionization unit 51, the remaining second concentrated water other than the second treated water used as reused water has a very high TDS of about 30,000 ~ 40,000 mg/L, so the raw water of the wastewater treatment plant is depleted. Biological treatment can be performed by supplying and mixing 3 to 4 times the generation amount of the second concentrated water obtained from the ionization unit 51, and a biological process applying a high-efficiency air diffuser is applied to minimize the cost and site.

In other words, the technology applied to the wastewater treatment plant so far has limitations in reducing the amount of concentrated water, so it is not possible to reduce the amount of concentrated water anymore, but the capacitive desalination (CDI) or reverse electrodialysis (EDR) process proposed in the present invention In the case of treatment, the amount of concentrated water can be drastically reduced because it can be increased up to 90%. In the case of the second concentrated water generated in the capacitive desalination (CDI) or reverse electrodialysis (EDR) process, the concentration rate is very high, so a part of the raw water from the wastewater treatment plant is converted to capacitive desalination (CDI) or reverse electrodialysis ( It is mixed with the second concentrated water obtained in the EDR) process so that a high-efficiency biological treatment is performed.

Through a high-efficiency biological treatment process, it is possible to sufficiently satisfy emission limit standards such as Biochemical Oxygen Demand (BOD), Total Nitrogen (T-N), and Total Phosphorus (T-P).

The biological treatment processes applied to the existing wastewater treatment process have to supply air required for the activity of aerobic microorganisms in the aeration tank, i.e., oxygen to the aeration tank.Therefore, an air supply means such as Root's Blower is provided in the aeration tank for 24 hours. Air must be supplied, and in the case of general aeration tanks, almost all of them have a depth of about 5m, and an air supply pipe is installed under the aeration tank, and a number of air diffusers are calculated according to the amount of air supplied to this pipe, and several air diffusers are installed. Supply oxygen to

However, depending on the type of the air diffuser and the water temperature in the aeration tank, the oxygen transfer rate is slightly different, but at a depth of 5m, it is approximately 7 to 15%. It should be selected as at least cm ² .

However, in the case of the existing biological treatment process, if the concentration of BOD or nitrogen in the raw water increases or the inflow flow rate increases due to the expansion of the plant or the addition of the process, wastewater treatment without an increase in the aeration tank, the increase in the amount of air diffusers, and the capacity of the blower Because it is impossible, it is virtually impossible to flexibly cope with various field situations.

In addition, in the case of the existing diffuser method, since oxygen is supplied from the bottom of the aeration tank to the top, 0.5kg/cm ² which has a higher pressure than the water pressure of the aeration tank depth 5m. Since the above blower must be used and the oxygen supply line is installed under the aeration tank and the diffuser is installed, work is possible only when the aeration tank is empty. In the case of replacement due to cracking or damage, etc., it is a reality that maintenance is very difficult as it is possible to work only when the aeration tank is empty.

For the above reasons, in the case of an aeration tank in which an existing air diffuser is installed, it is difficult to supply additional oxygen when fluctuations in the inflow load and an increase in inflow flow rate occur. Therefore, it is impossible to process with the existing aeration tank capacity, and the aeration tank must be expanded.

However, unlike the conventional method, the air diffuser according to the present invention has a circulation supply pipe, which is a wastewater circulation line, and a supply pipe, which is an air (oxygen) supply line, on the upper part of the aeration tank, so that it is not only possible to easily increase the line (pipe) without emptying the aeration tank. Since the oxygen supply principle is a method of increasing the oxygen delivery efficiency by increasing the circulation of wastewater rather than increasing the oxygen supply, and increasing the contact efficiency with the wastewater, the oxygen delivery efficiency is higher than that of the existing diffuser method. It is very high, and since it is possible to increase the flow rate easily through the inverter control of the circulation pump, the method of increasing the oxygen supply amount is also very simple, and it is possible to actively cope with the influent load fluctuation.

And, unlike the conventional diffuser method, the air diffuser according to the present invention has a circulation supply pipe and a supply pipe at the top, so that the suction pressure at which air is sucked in by the rapid flow rate of the aerated water mixed with wastewater and air is generated in the supply pipe. Even with a very low pressure blower, there is no problem with the supply of oxygen to the aeration tank.

In other words, there is no problem in supplying oxygen to the aeration tank sufficiently with a low pressure blower of 0.2 kg/cm ² or less because the intake pressure of air (oxygen) is generated in the oxygen supply line (supply pipe) by the rapid flow rate of the aerated water .

In addition, in the supply pipe of the present invention, oxygen is separately supplied through a separate line, that is, a double line inside the wastewater circulation line, so that wastewater and air (oxygen) are mixed in the water jet reaction unit located above the aeration tank.

Therefore, the high-efficiency biological treatment process has the advantage that the oxygen transfer rate can be increased by 50% or more compared to the existing air diffuser, so that the required site is less. As it requires less, energy is saved by about 20% or more compared to the method of supplying oxygen to the existing diffuser. That is, biological treatment can be performed in a minimum space and at a minimum cost, thereby minimizing initial investment and maintenance costs.

In addition, since the waterjet reaction unit according to the present invention is made of stainless steel and is not a method of delivering oxygen (air) through the pores of the diffuser, the oxygen transfer efficiency decreases due to clogging of the existing diffuser. Because there is no cracking or damage caused by hardening of the composition, it can be used semi-permanently rather than consumables like the existing diffuser.

According to an embodiment, the biological treatment unit 53 includes a circulation pump unit 100 for forcibly circulating the wastewater stored in the aeration tank 300 through the circulation supply pipe 110 as shown in FIGS. 3 to 5; It is disposed in communication with the circulation supply pipe 110, and includes a water jet reaction unit 200 for ejecting wastewater circulating and supplied along the circulation supply pipe 110 and aeration mixed with external air downward into the aeration tank.

Therefore, the biological treatment unit 53 basically increases the flow rate of the wastewater circulated through the shaft nozzle 211, and inhales external air in the atmosphere through the waterjet reaction chamber in which the pressure is reduced by increasing the flow rate. The aeration containing air bubbles is continuously supplied into the aeration tank.

The circulation pump unit 100 includes an inverter 130 for controlling a flow rate that controls the driving speed of the circulation pump 120, a flow meter 140 that measures the flow rate of the circulating wastewater, and a pressure gauge that measures the pressure of the circulating wastewater ( 150).

The circulation pump 120 is organically controlled according to the amount of dissolved oxygen in the wastewater stored in the aeration tank by the control of the flow rate control inverter 130, the amount of wastewater, and the residual amount of organic matter contained in the wastewater, so that it is suitable for the stored wastewater. It is configured to circulate a large amount of wastewater inside.

That is, the circulation pump 120 controlled by the flow control inverter 130 performs a function of internally circulating the wastewater stored in the aeration tank by sucking wastewater from the bottom of the aeration tank and supplying it to the circulation supply pipe 110, and One or more water jet reaction units 200 are formed in 110) so that a large amount of air is mixed in the wastewater supplied through the circulation pump 120 to be recirculated and supplied to the aeration tank.

Here, the driving speed of the circulation pump 120 controlled by the flow rate control inverter 130 is the flow rate and properties of the incoming wastewater, and the pollutant load of each pollutant, the capacity of the aeration tank, the discharge allowance standard, and the waterjet reaction unit ( 200) is adjusted according to the number of formations.

And, in the future, if there is a change in the flow rate and properties of the inflow wastewater, and the contaminant load condition of each pollutant, or if you want to increase the amount of oxygen supply, the solution is solved by increasing the circulation amount of the circulation pump 120, or if even this is insufficient, the circulation supply pipe 110 A water jet reaction unit 200 is added to increase the aeration amount.

On the other hand, the water jet reaction unit 200, which mixes air into the wastewater supplied from the circulation pump unit 100 and blows it into the aeration tank 300, has a core function of inducing a strong impact between the wastewater and air to generate microbubbles. Perform.

The water jet reaction unit 200 communicates with the circulation supply pipe 110 as shown in FIGS. 5 to 6 and is disposed upright in the aeration tank 300, and the shaft pipe nozzle 211 forms a reduced pressure state by a shaft pipe at the bottom. One or more wastewater discharge pipes 210 formed therein; At least one supplying air end 221 is installed in the shaft pipe nozzle 211 of the wastewater discharge pipe 210 to introduce air into the shaft pipe nozzle 211 in which depressurization is formed due to the pressure deviation between the atmosphere and the shaft pipe nozzle 211 Supply pipe 220; And the upper end is installed in a state surrounding the outer wall of the shaft pipe nozzle 211 to form a water jet reaction chamber 240, and through the supply pipe 220 by the wastewater discharged through the shaft pipe nozzle 211 and decompression. 211) and a mixing and blowing pipe 230 for blowing downwardly into the aeration tank 300 aeration mixed with air supplied to the inside.

Here, the mixing jet pipe 230 is made of PE, which is a non-metallic material, so that it is not corroded and is light in weight, so it can be easily installed.

In addition, flanges 212 and 231 are formed to correspond to the outer diameter of the wastewater discharge pipe 210 constituting the waterjet reaction unit 200 and the upper part of the mixing discharge pipe 230, and the upper part of the mixing discharge pipe 230 Is assembled in a flange structure through the flanges 212 and 231, and a waterjet reaction chamber 240 is formed on the upper part of the mixing jet pipe, whose upper part is shielded by the flange 231.

That is, the waterjet reaction chamber 240 has a closed upper portion, and a re-suction hole 241 is formed on the outer surface as described later, so that the air rising along the mixing jet pipe 230 is re-suction hole 241 ), the wastewater around the waterjet reaction chamber 240 is re-sucked through the re-suction hole 241 while preventing leakage through.

In particular, the water jet reaction chamber 240 is closed in a "┏" shape to maintain a set pressure, thereby preventing the phenomenon that the air remaining in the aerated water sprayed through the mixing and blowing pipe 230 is resuspended and discharged.

Therefore, the water jet reaction chamber 240 is formed at the upper part of the mixing spray pipe 230 and accommodates the shaft pipe nozzle 211 and the upper part is closed, and is distributed through the circulation supply pipe 110 and supplied to the wastewater discharge pipe 210 As the wastewater passes through the shaft nozzle 211 disposed in the waterjet reaction chamber 240, the flow rate increases, thereby forming a depressurized state of the waterjet reaction chamber 240.

The shaft pipe nozzle 211 is configured such that the width becomes narrower from the top to the bottom so that the flow rate increases as the wastewater passes the narrowed width, and a reduced pressure state is formed.

At this time, the wastewater rapidly supplied to the waterjet reaction chamber 240 through the shaft pipe nozzle 211 and the air supplied from the separate supply pipe 220 meet in the waterjet reaction chamber 240, resulting in a very strong and rapid shock reaction. In this process, air is dispersed in the form of microbubbles, and at the same time, wastewater forms a very strong turbulent flow, which promotes faster diffusion of air.

That is, the wastewater supplied from the shaft pipe nozzle 211 and the air supplied through the supply pipe 220 are rapidly mixed to form aeration water, and the aerated water is discharged downward to the lower portion of the aeration tank through the mixing jet pipe 230 , It is mixed with the wastewater stored in the aeration tank 300 to increase the amount of dissolved oxygen in the wastewater.

In addition, the aerated water in which air and wastewater are mixed in the waterjet reaction unit 240 is discharged from the top to the bottom of the aeration tank 300 through the mixing jet pipe 230 along with the wastewater, and is dispersed in all directions in the aeration tank. ) Rapidly increases the oxygen transfer efficiency of wastewater stored in).

In particular, in this embodiment, as shown in FIGS. 5 to 7, the mixing jet pipe 230 is configured in a cyclone type in which a spiral guide piece 232 is disposed on an inner wall, so that wastewater and air are collected in the waterjet reaction chamber 240. The mixed aerated water is discharged in the form of a spiral vortex by the spiral guide piece 232 formed on the inner wall of the mixing spray pipe 230 in the process of being ejected downward through the mixing spray pipe 230.

If configured in this way, the microbubbles generated in the waterjet reaction chamber 240 can be efficiently supplied to the lower part of the aeration tank 300, which is the inflow direction of the wastewater, and the microbubbles and the waste water including the same can be faster and faster to the lower part of the aeration tank 300 It flows naturally and forms a spiral vortex.

In addition, the aerated water ejected to the bottom of the aeration tank 300 through the mixing spout pipe 230 diffuses and rises as a whole through the flow of the wastewater, and in this process, some of the microbubbles are re-mixed through the flow of the wastewater. It is re-introduced into the waterjet reaction chamber (240) of 230) and the contact time with the wastewater is increased, thereby maximizing air cutting efficiency.

To this end, in this embodiment, some of the aerated water ejected through the mixing jet pipe 230 is re-introduced to the side wall of the water jet reaction chamber 240 as shown in FIGS. 3, 5 and 6 A re-suction hole 241 that ejects downwardly into the aeration tank 300 along the ejection pipe 230 is formed.

That is, one or more re-suction holes 241 are formed in the water jet reaction chamber 240, and the aeration tank 300 through the re-suction holes 241 in the decompression section in which a decompression state is formed by the aeration tank 300 and the shaft nozzle 211. ), but the wastewater stored in the water jet reaction chamber 240 is configured to be introduced into the waterjet reaction chamber 240, but the re-suction holes 241 are configured to be formed on the side of the mixing jet pipe 230.

In particular, in this embodiment, the induction tube 242 is disposed in the re-intake hole 241, and the suction end 242a of the induction tube 242 is configured to have a relatively lower height than the re-intake hole 241, A phenomenon in which the air ejected through the mixing jet pipe 230 is resuspended is suppressed, and the floating wastewater is stably re-inhaled.

In addition, in the present embodiment, a diffusion plate 250 is disposed below the mixing and blowing pipe 230, and the wastewater discharged downward through the mixing and blowing pipe 230 is diffused outward through the diffusion plate 250, and thus the aeration tank (10) It is to be mixed with the stored wastewater.

A plurality of permeable holes are formed in the diffusion plate 250, and some of the mixed and discharged aerated water is discharged downward through the permeable hole 251, and the remaining aerated water is diffused outward through the diffusion plate 250.

In particular, in the present embodiment, the diffusion plate 250 is disposed in an elevating structure through the elevating guide 252 at the end of the mixing ejection pipe, and is resiliently pulled upward by the traction spring 253, thereby forming the mixing ejection pipe 230 According to the amount and pressure of the aeration discharged through the system, the discharged aerated water is spread by ascending and descending flexibly.

When configured in this way, the aerated water ejected through the mixing and ejection pipe 230 is partially shielded by the diffusion plate 250 and diffused in the aeration tank 10, so that the wastewater stored in the aeration tank 10 and the stable mixing Through the stable flow of wastewater, the amount of dissolved oxygen in the wastewater is stably increased within a short time.

Next, the activated carbon adsorption unit 55 is for removing harmful substances present in the third treated water obtained from the biological treatment unit 53 by applying an activated carbon adsorption method, for example, Per-Fluorinated Compounds (PFC). Is removed by adsorption.

Since there are not many dissolved substances in raw water, the particulate matter is mainly removed through coagulation, precipitation and filtration, but recently, the presence of soluble trace organic compounds has been revealed, and organic compounds due to eutrophication are also increasing, so the dissolution of organic compounds. The need for treatment of components is increasing, and the activated carbon adsorption method is an effective method for removing dissolved organic matter.

Perfluorinated compounds (PFCs) are used in the entire industry and are non-degradable substances that are not easily degraded naturally. They are highly likely to accumulate in the body or in nature, and are found to be toxic substances that cause hormonal disturbances when exposed to the ecosystem.

Since harmful substances including perfluorinated compounds (PFCs) are removed through the activated carbon treatment unit 55, even if the second concentrated water is treated through the activated carbon treatment unit 55 and then discharged, dissolved organic compounds, especially perfluorinated compounds, No problem arises.

Meanwhile, the activated carbon backwash water generated through the backwash process in the activated carbon adsorption unit 55 may be supplied back to the wastewater treatment plant 10.

The sewage treatment system 1 according to another embodiment is reused by applying a reverse osmosis technique to the first treated water provided from the sewage treatment unit 10 and the sewage treatment unit 10 to treat raw water from a sewage treatment plant for discharge. And a reuse treatment unit 30 for obtaining water and first concentrated water, and a second concentrated water treatment module 70 for processing the first concentrated water. The second concentrated water treatment module 70 separates ions by applying a capacitive desalination technique to the first concentrated water obtained from the reuse treatment unit 30 to obtain second concentrated water and second treated water to be used as reused water. The deionization unit 51 and the second concentrated water obtained from the deionization unit 51 are heated to evaporate water through the evaporation and concentration unit 73 and the evaporation and concentration unit 73 to solidify the remaining material after water is evaporated. It includes a crystallization part (75).

Since the deionization unit 51 constituting the second concentrated water treatment module 70 has the same function as that of the first concentrated water treatment module 50, a description thereof will be omitted.

Next, the evaporation and concentration unit 73 is for separating water and other substances from the second concentrated water by heating the second concentrated water obtained from the deionization unit 51 to evaporate the water contained in the second concentrated water, The evaporated water is condensed through cooling to generate condensed water, which can be supplied to a consumer as reused water.

The crystallization unit 75 is for solidifying the material remaining after water is evaporated in the evaporation and concentration unit 73, and the water generated in the crystallization unit 75 is condensed to generate condensed water, and can be supplied to a consumer as reused water.

Concentrated water discharged from the deionization unit 51 using the membrane capacitive desalination (mCDI) technique because it is concentrated up to 97.5% of raw water through the deionization unit 51 using the membrane capacitive desalination (mCDI) technique. Is about 2.5% of raw water, and the amount of generation is very low.

For example, raw water is 100,000m ³ / day If the concentrated water is about 2,500m ³ / days, so the biological processing unit 53 and the activated carbon absorption unit 55, instead of the process, evaporation section 73 for discharge through the When the process of the crystallization unit 75 is passed, a complete no-discharge process can be implemented.

However, the second concentrated water discharged from the deionization unit 51 using the membrane capacitive demineralization method (mCDI) or reverse electrodialysis (EDR) is said to be 2.5% of the raw water, and the generation amount is very low, but the concentrated water is evaporated and concentrated daily. If the process and crystallization process are performed, there is room for increased production cost of reused water.

On the other hand, the method for treating concentrated water in a sewage or wastewater treatment plant proposed as a preferred embodiment in the present invention is a reverse osmosis technique for the first treated water obtained by treating raw water from a sewage treatment plant for discharge, as shown in FIG. And obtaining reused water and first concentrated water by applying (S100); Separating ions by applying a capacitive desalting technique or a reverse electrodialysis technique to the first concentrated water obtained through step S100 to obtain second treated water to be used as second concentrated water and reused water (S200); Decomposing and removing organic matter contained in the second concentrated water obtained through step S200 by microorganisms (S300); And removing harmful substances present in the third treated water obtained through step S300 by adsorption of activated carbon (S400). Steps S100 to S400 may be performed in each element shown in FIG. 2.

According to another embodiment, the method for treating concentrated water in a sewage or wastewater treatment plant for implementing ZLD, as shown in FIG. 9, uses a reverse osmosis technique for the first treated water obtained by treating raw water from a wastewater treatment plant for discharge. Applying and obtaining reused water and first concentrated water (S100); Separating ions by applying a capacitive desalting technique to the first concentrated water obtained through step S100 to obtain second concentrated water and second treated water to be used as reused water (S200); Evaporating water by heating the second concentrated water obtained through step S200 and condensing the evaporated water to be used as reused water (S500); And a step (S600) in which water is evaporated through step S500 and the remaining material is solidified and discharged, and the water generated in this process is condensed and used as reused water (S600). Step S100, step S200, step S500, and step S600 may be performed in each element shown in FIG. 2.

1. Sewage water treatment system
10. Wastewater treatment unit 30. Reuse treatment unit
50. The first concentrated water treatment module 51. Deionization unit
53. Biological treatment unit 55. Activated carbon adsorption unit
70. The second concentrated water treatment module 73. Evaporation and concentration unit
75. Crystallization section
100. Circulation pump unit 110. Circulation supply pipe
120. Circulation pump 130. Inverter for flow control
140. Flow meter 150. Pressure gauge
200. Waterjet reaction unit 210. Wastewater discharge pipe
211. Shaft nozzle 212. Flange
220. Supply engine 221. Supply air stage
230. Mixing spout 231. Flange
232. Spiral guide piece 240. Water jet reaction chamber
241. Resuction hole 242. Induction tube
242a. Suction end 250. diffuser
251. Pitcher 252. Elevating Guide
253. Traction spring 300. Aeration tank

Claims (5)

A reuse treatment process in which recycled water and first concentrated water are obtained by applying a reverse osmosis technique to the first treated water obtained by treating raw water from a wastewater treatment plant for discharge;
A deionization process of separating ions by applying a capacitive desalting or reverse electrodialysis technique to the first concentrated water obtained through the reuse treatment process to obtain second concentrated water and second treated water to be used as reused water;
A biological treatment process in which organic matter contained in the second concentrated water obtained through the deionization process is decomposed and removed by microorganisms; And
And an activated carbon adsorption process of removing harmful substances present in the third treated water obtained through the biological treatment process by adsorption of activated carbon,
The biological treatment process,
A circulation pump for forced circulation of wastewater stored in the aeration tank through a circulation supply pipe; It is arranged to be in communication with the circulation supply pipe, and is made through a biological treatment unit including a water jet reaction unit that ejects wastewater circulating and supplied along the circulation supply pipe and an aeration mixed with external air downward into the aeration tank,
The water jet reaction unit,
One or more wastewater discharge pipes disposed upright in the aeration tank so as to communicate with the circulation supply pipe, and having a shaft pipe nozzle forming a reduced pressure state by a shaft pipe at a lower end thereof;
One or more air supply pipes for introducing air into the shaft pipe nozzle in which depressurization is formed by a pressure difference between the atmosphere and the shaft pipe nozzle by internally installing an air supply end in the shaft pipe nozzle of the wastewater discharge pipe; And
The upper end is installed with the outer wall of the shaft pipe nozzle to form a waterjet reaction chamber, and the aeration water mixed with the wastewater discharged through the shaft pipe nozzle and the air supplied into the shaft pipe nozzle through the supply pipe through decompression is blown downward into the aeration tank. Including a mixing spout tube to,
A diffusion plate is disposed under the mixing and ejection pipe, and a plurality of permeable holes are formed in the diffusion plate, so that some of the mixed and discharged aerated water is discharged downward through the permeable hole, and the remaining aerated water is diffused outward through the diffusion plate. Is mixed into the wastewater stored in the aeration tank,
The diffusion plate is arranged in a lifting structure through a lifting guide at the end of the mixing spout pipe, and is elastically pulled upward by a traction spring, and the number of aeration discharged while elastically ascending and descending according to the aeration amount and pressure ejected through the mixing spout pipe A method for treating concentrated water generated in a sewage or wastewater treatment plant effluent reuse process, characterized in that configured to diffuse. According to claim 1,
The capacitive desalination technique is a membrane capacitive desalination technique in which a membrane of cation and anion is added. A method of treating concentrated water generated in a process of recycling effluent water from a sewage or wastewater treatment plant. According to claim 1,
The biological treatment process is a method for treating concentrated water generated in a sewage or wastewater treatment plant effluent reuse process, characterized in that it is performed on the mixed water obtained by mixing the raw water of the wastewater treatment plant with the second concentrated water obtained through the deionization process. delete A wastewater treatment unit that treats raw water from a sewage treatment plant for discharge, a reuse treatment unit that obtains reused water and first concentrated water by applying a reverse osmosis technique to the first treated water provided from the sewage treatment unit, and the first concentrated water. In a wastewater treatment system comprising a concentrated water treatment module to treat,
The concentrated water treatment module,
A deionization unit for separating ions by applying a capacitive desalting technique to the first concentrated water obtained from the reuse treatment unit to obtain second concentrated water and second treated water to be used as reused water;
A biological treatment unit that decomposes and removes organic matter contained in the second concentrated water obtained by the deionization unit; And
And an activated carbon adsorption unit for removing harmful substances present in the third treated water obtained from the biological treatment unit by adsorption of activated carbon,
The biological treatment unit,
A circulation pump for forced circulation of wastewater stored in the aeration tank through a circulation supply pipe; It is disposed in communication with the circulation supply pipe, and comprises a water jet reaction unit for ejecting the wastewater circulating and supplied along the circulation supply pipe and the aeration mixed with external air downward into the aeration tank,
The water jet reaction unit,
One or more wastewater discharge pipes disposed upright in the aeration tank so as to communicate with the circulation supply pipe, and having a shaft pipe nozzle forming a reduced pressure state by a shaft pipe at a lower end thereof;
One or more air supply pipes for introducing air into the shaft pipe nozzle in which depressurization is formed by a pressure difference between the atmosphere and the shaft pipe nozzle by internally installing an air supply end in the shaft pipe nozzle of the wastewater discharge pipe; And
The upper end is installed with the outer wall of the shaft pipe nozzle to form a waterjet reaction chamber, and the aeration water mixed with the wastewater discharged through the shaft pipe nozzle and the air supplied into the shaft pipe nozzle through the supply pipe through decompression is blown downward into the aeration tank. Including a mixing spout tube to,
A diffusion plate is disposed under the mixing and ejection pipe, and a plurality of permeable holes are formed in the diffusion plate, so that some of the mixed and discharged aerated water is discharged downward through the permeable hole, and the remaining aerated water is diffused outward through the diffusion plate. Is mixed into the wastewater stored in the aeration tank,
The diffusion plate is arranged in a lifting structure through a lifting guide at the end of the mixing spout pipe, and is elastically pulled upward by a traction spring, and the number of aeration discharged while elastically ascending and descending according to the aeration amount and pressure ejected through the mixing spout pipe Wastewater treatment system, characterized in that configured to diffuse.

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