KR20160121666A - Water treatment apparatus using forward osmosis membrane bioreactor and reverse osmosis process - Google Patents

Abstract

The present invention relates to a water treatment apparatus using a forward osmosis bio-membrane bioreactor and a reverse osmosis process. The water treatment apparatus using a forward osmosis bio-membrane bioreactor and a reverse osmosis process according to the present invention comprises: a reactor for water-treating raw water using an activated sludge; a forward osmosis module installed inside the reactor and water-treating the raw water using an osmosis pressure between an induction solution and the raw water; and an external treatment bath installed outside the reactor, wherein the external treatment bath receives the first-treated raw water from the reactor, discharges ions contained in the first-treated raw water, supplies a portion of the sludge, as return sludge, to the reactor, and discharges the remainder as extra sludge. Therefore, a water treatment apparatus using a forward osmosis bio-membrane reactor and a reverse osmosis process capable of high concentration/high flux operation is provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment apparatus using a forward osmosis biofilm reaction tank and a reverse osmosis process,

The present invention relates to a water treatment apparatus using a positive osmosis biofilm reaction tank and a reverse osmosis process, and more particularly, to a water treatment apparatus using a positive osmosis biofilm reaction tank capable of high concentration / high flux operation using an external treatment tank and a reverse osmosis .

With the global population growth and the spread of pollution due to the development of industry, almost all countries will suffer water shortages by 2025, and half of them are expected to face a serious crisis in securing water resources. With increasing demand for water and limited water resources, there is growing interest in the reuse of wastewater.

The conventional sewage treatment process is based on a standard activated sludge process in which organic matter and nutrients in the wastewater are removed through the decomposition and ingestion of microorganisms in an aerobic tank and sedimentation is carried out to separate active microbes and treated water by sedimentation . However, conventional biological treatment processes have difficulty in water quality management due to problems such as sedimentation deterioration due to sludge expansion frequently occurring due to fluctuation of operating conditions and sludge loss.

In order to solve these problems, a biofilm reactor (MBR), which combines the advantages of the activated sludge process with the membrane technology, has been proposed by replacing the separation of sludge by conventional gravity sedimentation of biological treatment.

The biofilm reaction tank is composed of a bioreactor and a separation membrane, and it is not necessary to consider the sedimentation of the sludge by using solid-liquid separation using a membrane instead of the existing secondary sedimentation tank. Suspended Solid (SS) There is a high advantage. In addition, since the sedimentation is not taken into consideration, various constraints on operation are reduced, and it is possible to operate in a long solid retention time (SRT) independently of the hydraulic retention time (HRT). Long solids retention time is improved by increasing the concentration of MLSS (Mixed Liquor Suspended Solid) in the untreated tank to maintain the low F / M ratio and increasing the asset rate by increasing the sludge age.

Biofilm reactors use microfiltration (MF) or ultrafiltration (UF) membranes as separation membranes. The microfiltration membrane separates particles of about 0.1 ~ 10 ㎛, and the ultrafiltration membrane separates particles of about 10 ~ 1000 Å.

However, separation of particles smaller than those in existing membrane reactors has been required, and a FOMBR or OsMBR (Forward Osmosis Membrane Bioreactor) combined with a biofilm reactor and a positive osmosis membrane has been proposed.

However, since the positive osmosis biofilm reaction tank separates ions, the concentration of ions in the reaction tank is increased, which lowers the activity of microorganisms. In other words, biofilm reactors are required to concentrate microorganisms, but the activity of microorganisms is lowered by increasing the concentration of ions. Further, there is a problem of low flux due to diffusion of the inducing solution into the reaction tank.

Accordingly, it is an object of the present invention to provide a water treatment apparatus using a reverse osmosis process and a positive osmosis biofilm reaction tank capable of high concentration / high flux operation using an external treatment tank.

The present invention also provides a water treatment apparatus using a reverse osmosis process and a more efficient positive osmosis biofilm reaction tank by reusing pressure energy contained in an induction solution by using an energy recovery device to produce water by using a reverse osmosis module.

According to the present invention, the above objects can be accomplished by providing a reaction tank for water-treating raw water using activated sludge; A forward osmosis module installed inside the reaction tank for water treatment of the raw water using osmotic pressure between the inducing solution and the raw water; And a control unit which is installed outside the reaction tank, receives raw water treated first from the reaction tank, discharges ions contained in the raw water treated first, supplies a part of the sludge as a transportation sludge to the reaction tank, And a water treatment apparatus using a reverse osmosis process.

Here, it is preferable that the external treatment tank includes a solid-liquid separator for discharging ions and concentrating the sludge.

The solid-liquid separator may include at least one of a microfiltration (MF) membrane, an ultrafiltration membrane (UF) membrane, and a fibrous membrane filter.

Here, it is preferable that the ions are discharged as wastewater treatment plant effluent.

Here, the reaction tank is preferably provided with an air diffusing pipe for supplying air.

It is preferred that the reverse osmosis module further includes a reverse osmosis module connected to the forward osmosis module and producing water from the diluted induction solution using a reverse osmosis process.

Here, it is preferable that the reverse osmosis module re-supplies the induction solution filtered by the produced water to the forward osmosis module.

The reverse osmosis module may further include an energy recovery device for recovering the energy generated during the production of the produced water from the diluted induction solution and reusing it for the reverse osmosis process.

According to the present invention, there is provided a water treatment apparatus using a quasi-osmosis biofilm reaction tank and a reverse osmosis process in which water quality is improved using an external treatment tank and the overall efficiency is improved.

In addition, the concentrated ions in the reaction tank are discharged from the external treatment tank to maintain a high osmotic pressure difference between the reaction tank and the induction solution to increase the positive osmosis flux, and the activated sludge essential for biological treatment is concentrated in the external treatment tank and supplied to the reaction tank, / A forward osmosis biofilm reaction vessel capable of high flux operation and a water treatment apparatus using a reverse osmosis process are provided.

In addition, there are a biofilm reaction tank that can purify the raw water through the treatment of raw water by activated sludge, raw water by a positive osmosis module and raw water by a reverse osmosis module, and a water treatment device using a reverse osmosis Is provided.

Also, by reusing the pressure energy contained in the induction solution by the energy recovery device, a more efficient water treatment apparatus using the forward osmosis biofilm reaction tank and the reverse osmosis process is provided.

1 is a schematic view of a water treatment apparatus using a forward osmosis biofilm reaction tank and a reverse osmosis process according to an embodiment of the present invention,
FIG. 2 is a view schematically showing a biofilm reaction tank of the water treatment apparatus using the positive osmosis biofilm reaction tank and the reverse osmosis process of FIG. 1,
FIG. 3 is a diagram showing a comparison between the forward osmosis process and the reverse osmosis process,
FIG. 4 is a view schematically showing a filtration process in the forward osmosis membrane module of the water treatment apparatus using the forward osmosis membrane reactor and the reverse osmosis membrane reactor of FIG. 1,
FIG. 5 is a view schematically showing the external treatment tank of the water treatment apparatus using the positive osmosis biofilm reaction tank and the reverse osmosis process of FIG. 1,
FIG. 6 is a schematic view showing the reverse osmosis module of the water treatment apparatus using the positive osmosis biofilm reaction tank and the reverse osmosis process of FIG. 1;

Hereinafter, a water treatment apparatus using a positive osmosis biofilm reaction tank and a reverse osmosis process according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic view of a water treatment apparatus using a positive osmosis biofilm reaction tank and a reverse osmosis process according to an embodiment of the present invention. 1, a water treatment apparatus 100 using a forward osmosis biofilm reaction tank and a reverse osmosis process according to an embodiment of the present invention includes a reaction tank 110, a forward osmosis module 120 installed in the reaction tank 110, And a reverse osmosis module 140 connected to the external treatment tank 130 and the normal osmosis module 120 installed outside the reaction tank 110.

FIG. 2 is a view schematically showing a biofilm reaction tank of the water treatment apparatus using the positive osmosis biofilm reaction tank and the reverse osmosis process of FIG. 1;

The reaction tank 110 is configured to treat the raw water and provide the biological treatment space of the raw water. The reaction tank 110 purifies the raw water through the activated sludge, and passes the purified raw water through the membrane module, thereby filtering the sludge and the solids, thereby causing secondary purification. Here, the raw water may be sewage, wastewater or the like, and in the present invention, the membrane module is the forward osmosis module 120.

In the reaction tank 110, an activated sludge, that is, microorganisms is accommodated at an appropriate concentration and an air diffuser 111 for supplying air is installed. The acid pipe 111 may be installed at the bottom of the reaction tank 110.

Oxygen is required to maintain the activity of the activated sludge. When raw water is supplied into the reaction tank 110, oxygen supplied from an air infusion pump (not shown) is sprayed through the oxygen pipe 111. The activated sludge absorbs organic matter in the raw water, absorbs and decomposes the organic matter by oxygen, and purifies the raw water first.

FIG. 3 is a diagram showing a comparison between a forward osmosis process and a reverse osmosis process. Referring to FIG. 3A, in the Foward Osmosis process, pure water of a low concentration solution is absorbed into an induction solution by bringing a high concentration of a draw solution into contact with a low concentration solution through a semipermeable membrane, And then pure water is separated again from the solution. Referring to FIG. 3 (b), reverse osmosis is performed by applying a pressure higher than the osmotic pressure to the high concentration solution side through the semipermeable membrane in the equilibrium state of the fluid. In contrast to the positive osmosis phenomenon, And flows toward the low concentration solution side.

FIG. 4 is a view schematically showing the filtration process in the forward osmosis membrane module of the water treatment apparatus using the reverse osmosis process and the forward osmosis biofilm reaction tank of FIG. 1; Referring to FIG. 4, the forward osmosis module 120 serves as a membrane module in the reaction tank 110, and uses a forward osmosis membrane, unlike the conventional biofilm reaction vessel (MBR).

The forward osmosis module 120 may be a hollow fiber membrane module, a flat membrane module, or the like, provided that the membrane is a separation membrane for separating a solute having an ion and a molecular size within 10 angstroms. In the present invention, the forward osmosis module 120 is accommodated in the reaction tank 110. That is, the biofilm reaction tank according to the present invention is an immersion biofilm reaction tank.

The induction solution DS is introduced into the forward osmosis module 120 and the raw water purified by the activated sludge is introduced into the forward osmosis module 120 by osmotic pressure according to the concentration difference with the induction solution DS do. For example, when the forward osmosis module 120 is provided as a hollow fiber membrane, the induction solution DS is supplied to the inside of the hollow fiber membrane, and the first purified water outside the hollow fiber membrane is introduced into the hollow fiber membrane by osmotic pressure , The inductive solution is diluted draw solution (DDS) by the raw water.

On the other hand, the inducing solution (DS) should have high solubility in water in order to achieve a high osmotic pressure, and can separate the water and the inducing solution (DS) by using low energy, and the recovering rate of the separating material is preferably high. The induction solution (DS) is not limited in its kind, and various solutes including NaCl can be used.

That is, in the biofilm reaction tank according to the present invention, the raw water is primarily purified by decomposing the organic matter of the raw water by the microorganisms inside the reaction tank 110 by the oxygen supplied from the oxygen pipe 111, And then subjected to secondary purification by filtration.

FIG. 5 is a view schematically showing the external treatment tank of the water treatment apparatus using the positive osmosis biofilm reaction tank and the reverse osmosis process of FIG. 1;

The outer treatment tank 130 discharges the concentrated ions in the reaction tank 110 to increase the osmotic pressure difference between the reaction tank 110 and the induction solution DS to increase the flow rate through the normal osmosis module 120, And to concentrate the activated sludge useful for treatment. That is, the external treatment tank 130 is configured to maintain a high concentration / high flux in the reaction tank 110 and is disposed outside the reaction tank 110.

Since the forward osmosis module 120 is provided as a separation membrane for separating a solute having an ion and a molecular size of 10 Å or less, only pure water flows into the osmosis module 120, and other substances including ions are filtered. That is, in the reaction tank 110, the activated sludge reacts with the organic matter, and the generated sludge S and the ion I remain filtered.

There is an advantage in that pure water can be filtered by pure osmosis module 120 but a low flux problem occurs in which the flow rate through the osmosis module 120 is affected by the activity of the activated sludge. Specifically, the biological treatment of activated sludge requires a long solid retention time (SRT). However, since the ion (I) is filtered by the forward osmosis module (120), it is affected by the biological activity of the activated sludge by the ion (I). Since pure water is introduced into the inside of the forward osmosis module 120 to dilute the inducing solution DS but ions are filtered and accumulated outside the forward osmosis module 120, The car becomes smaller. Further, when the desensitization solution DS in the forward osmosis module 120 is diffused out of the forward osmosis module 120, the concentration difference can be smaller.

That is, the pure osmosis module 120 is capable of filtering only pure water, but has a problem of low concentration / low flux.

The external treatment tank 130 is provided outside the reaction tank 110 to receive the first purified raw water in the reaction tank 110 to maintain the high concentration / high flux in the reaction tank 110. The primary purified water includes sludge (S), ion (I), and water.

The external treatment tank 130 discharges water and ions (I) from the first purified raw water as wastewater treatment plant effluent. Specifically, the external treatment tank 130 includes a solid-liquid separating section 131 capable of discharging ions and concentrating the sludge. The solid-liquid separator 131 may be provided with at least one of a microfiltration (MF) membrane, an ultrafiltration (UF) membrane, and a fibrous filter.

The microfiltration membrane is a membrane separating particles having a solute size of about 0.1 to 10 mu m, and has a pore size of about 0.05 to 10 mu m and a porosity of at least 70% of the total volume. Bacteria, latex or colloidal particles are separated by the microfiltration membrane. Ultrafiltration membranes are used to separate colloidal particles or macromolecules with molecular sizes ranging from several thousand to several hundred thousand daltons, and are applied to the separation of microorganisms, viruses and the like. The fibrous filter means a filter made of a fiber material having a pore diameter of 1 to 10 μm and is suitable for the concentration and separation of microorganisms that occupy most of the activated sludge although the separation function is less than that of a microfiltration membrane or a filtration membrane. . That is, the external treatment tank 130 separates the water and the ion (I) from the raw water subjected to the primary treatment through at least one of a microfiltration membrane, an ultrafiltration membrane, and a fibrous filter to discharge it as a wastewater treatment plant effluent do. However, in the present embodiment, the outer treatment tank 130 uses a microfiltration membrane, an ultrafiltration membrane, a fibrous filter, or the like in order to separate and discharge the ions I, but the present invention is not limited thereto. Of course.

Among the first purified raw water supplied to the external treatment tank 130, the sludge S is concentrated and re-supplied to the reaction tank 110 as a transport sludge, and a part of the sludge is discharged to an excess sludge. The transport sludge is preferably supplied in such an amount that the inside of the reaction tank 110 is maintained in an appropriate MLSS (Mixed Liquer Suspended Solid).

In summary, the primary purified raw water in the reaction tank 110 is discharged to the external treatment tank 130, thereby preventing the concentration difference between the inside and the outside of the forward osmosis module 120 from being lowered by discharging the ions I . In addition, the discharged sludge S is concentrated by the external treatment tank 130 and supplied to the inside of the reaction tank 110 to maintain proper MLSS (Mixed Liquer Suspended Solid). Therefore, the high concentration / high flux in the reaction tank 110 increases the efficiency.

FIG. 6 is a schematic view showing the reverse osmosis module of the water treatment apparatus using the positive osmosis biofilm reaction tank and the reverse osmosis process of FIG. 1;

The reverse osmosis module 140 is a structure for producing the production water from the dilution solution DDS in the normal osmosis module 120. Referring to FIG. 6, the reverse osmosis module 140 includes a pump 141, a reverse osmosis separator 142, and an energy recovery device 143.

As described above, in the reverse osmosis process, when a pressure higher than the osmotic pressure is applied to the high concentration solution side with the semi-permeable membrane interposed therebetween in the fluid equilibrium state, contrary to the positive osmosis phenomenon, pure water flows from the high concentration solution to the low concentration solution side. In this embodiment, the induction solution DS is diluted due to the inflow of water from the positive osmosis module 120, the diluted induction solution DDS is pressurized by the pump 141, and the diluted induction solution DDS is pure The water passes through the reverse osmosis membrane (142).

The energy recovery device 143 is an energy reduction device that recovers and reuses high-pressure energy discharged and lost in the reverse osmosis process. The inductive solution DS discharged in the reverse osmosis process without passing through the membrane has the energy provided by the pump 141 as it is. The energy recovery device 143 uses the diluted induction solution DDS pressurized by the pump 141 as energy to pressurize the diluted induction solution DDS by recovering some of the lost pressure energy from the diluted induction solution DDS Device. The energy recovery device 143 may be used, for example, by rotating the turbine using a high-pressure induction solution DS and connecting it to the impeller of the pump 141 to recover energy.

That is, the induction solution DS is diluted by the water introduced from the forward osmosis module 120, and the diluted induction solution DDS is supplied to the reverse osmosis module 140 side. Thereafter, the pump 141 pressurizes the diluted induction solution DDS at a high pressure, and pure water contained in the diluted induction solution DDS passes through the reverse osmosis separation membrane 142 and is produced. On the other hand, the diluted induction solution (DDS) from which the pure water is discharged is again supplied to the high-concentration induction solution DS and is supplied to the forward osmosis module 120. The high pressure energy of the induction solution DS is supplied to the energy recovery device (143) and used to operate the pump (141).

On the other hand, since many materials are filtered in the forward osmosis module 120, the reverse osmosis module 140 does not cause a fouling phenomenon in which the membrane is contaminated by the materials remaining on the membrane surface.

Hereinafter, the operation of the water treatment apparatus using the positive osmosis biofilm reaction tank and the reverse osmosis process according to one embodiment of the present invention will be described.

First, raw water is supplied into the reaction tank 110. In the reaction tank 110, a large amount of microorganisms as activated sludge exist, and oxygen is supplied from the oxygen pipe 111 to the inside of the reaction tank 110.

The activated sludge firstly purifies the raw water by adsorbing, absorbing and decomposing organic substances in the raw water using the supplied oxygen.

Meanwhile, a high concentration of the inductive solution DS is supplied to the inside of the normal osmosis module 120. The pure water of the raw water is supplied to the inside of the forward osmosis module 120 by the osmotic pressure according to the concentration difference between the primary purified water and the inducing solution DS, and the inducing solution DS is mixed with the pure water, Solution (DDS).

Materials such as sludge S and ions I are filtered by the forward osmosis module 120 and primary purified water containing substances such as sludge S and ions I in the reaction tank 110 And is discharged to the external treatment tank 130.

The ions (I) in the secondary purified raw water flowing into the external treatment tank 130 are separated by a microfiltration membrane, an ultrafiltration membrane, a fibrous filter and the like, and discharged as sewage treatment effluent. Some of the sludge And is supplied again to the reaction tank 110 as the transport sludge so that the inside of the reaction tank 110 maintains proper MLSS.

Meanwhile, the induction solution (DDS) diluted in the forward osmosis module (120) is supplied to the reverse osmosis module (140) side. Thereafter, the pump 141 pressurizes the diluted induction solution DDS at a high pressure, and pure water contained in the diluted induction solution DDS passes through the reverse osmosis separation membrane 142 and is produced. On the other hand, the diluted induction solution (DDS) from which the pure water is discharged is again supplied to the high-concentration induction solution DS and is supplied to the forward osmosis module 120. The high pressure energy of the induction solution DS is supplied to the energy recovery device (143) and used to operate the pump (141).

Therefore, according to the present invention, there is provided a water treatment apparatus using a forward osmosis biofilm reaction tank and a reverse osmosis process that can perform high concentration / high flux operation using an external treatment tank.

The scope of the present invention is not limited to the above-described embodiments, but may be embodied in various forms of embodiments within the scope of the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

100: Water treatment system using reverse osmosis process
110: Reactor 120:
130: External Treatment Unit 140: Reverse Osmosis Module

Claims (8)

A reaction tank for water-treating raw water using activated sludge;
A forward osmosis module installed inside the reaction tank for water treatment of the raw water using osmotic pressure between the inducing solution and the raw water; And
And the other of the sludge is supplied to the reaction tank as the transfer sludge, and the remaining sludge is supplied to the reaction tank And a water treatment apparatus using the reverse osmosis process. The method according to claim 1,
Wherein the external treatment tank includes a solid-liquid separator for discharging ions and concentrating the sludge, and a water treatment apparatus using the reverse osmosis process. 3. The method of claim 2,
Wherein the solid-liquid separator includes at least one of a microfiltration (MF) membrane, an ultrafiltration (UF) membrane, and a fibrous membrane filter, and a water treatment process using a reverse osmosis Device. The method according to claim 1,
Wherein the ion is discharged as a wastewater treatment plant effluent, and a water treatment apparatus using a reverse osmosis process. The method according to claim 1,
Wherein the reaction tank is provided with an air diffuser for supplying air, and the water treatment apparatus using the reverse osmosis process. 6. The method according to any one of claims 1 to 5,
Further comprising a reverse osmosis module connected to the forward osmosis module and producing a product water from the diluted induction solution by using a reverse osmosis process, and a reverse osmosis module using the reverse osmosis process. The method according to claim 6,
Wherein the reverse osmosis module feeds the filtered induction solution to the forward osmosis module and the reverse osmosis module. 6. The method of claim 5,
Wherein the reverse osmosis module includes an energy recovery device for recovering the energy generated during the production of the produced water from the diluted induction solution and reusing it for the reverse osmosis process. Water treatment device.

Images