KR20170023237A - System for producing reusable water and concentrated sewage from waste water and method using the same - Google Patents

Abstract

The present invention relates to a method for producing an aqueous solution containing a water-soluble organic solvent, which is connected to a front end or a rear end of a primary settling tank for primary infiltration of influent water flowing through a gypsum of a sewage treatment plant, module; A first supply pipe connected to a first end of the forward osmosis module to supply a supply solution, a first discharge pipe connected to a second end of the forward osmosis module, A second supply pipe connected to the third end of the forward osmosis module for supplying the induction solution, a second discharge pipe connected to the fourth end of the forward osmosis module for discharging the induction solution, And the diluted induction solution passing through the inducing solution transfer section is usable as reusing water. The present invention provides a system for producing concentrated sewage and reusing water from sewage water.

Description

System for producing concentrated sewage and reused water from sewage and method using the same. {System for producing reusable water and concentrated sewage from waste water and using the same same}

The present invention relates to a system for producing concentrated sewage and reused water having a reduced treatment amount from sewage using a fresh water desalination system using a fertilizer composition as an induction solution, and a method using the same.

About two-thirds of the world's water demand is used as agricultural water, and reuse of agriculture water is the most important part in the sewage reuse field. In many countries, efforts are being made to treat domestic sewage and reuse as irrigation water. It is known that only 67 cases of reuse report of agricultural wastewater from sewage treatment have been reported recently.

  As a result of the empirical experiment on the feasibility of reuse of agricultural wastewater in sewage treatment water, reuse of sewage wastewater as irrigation water has resulted in a remarkable improvement in the water quality improvement effect, including the effect of increasing the organic matter removal rate to 60% It was shown.

However, since the chloride content of sewage-treated water is high, it is difficult to use it directly as agriculture water, so that the re-use rate of agriculture water is low. Currently, the method currently used for removing chloride from sewage- (Reverse Osmosis). However, the reverse osmosis process requires a considerably high pressure since osmotic pressure is greatly generated. As a result, sewage treatment reuse using the reverse osmosis process requires a lot of installation and operation costs, which is difficult to apply in practice.

On the other hand, the forward osmosis process (FO) shown in Fig. 1 (B) is a technique for producing fresh water (reclaimed water) using the difference in osmotic pressure between the feed solution and the induction solution with the membrane therebetween, And it is considered that it is a new technology that can replace the reverse osmosis process in the future.

Currently, most of the pure osmosis technology is being developed as an alternative to water shortage by producing fresh water from raw water (seawater or nautical), and studies to treat sewage using pure osmosis technology are at an early stage .

As shown in Korean Patent Publication No. 10-1286044, the biggest problem in practical application of the positive osmosis technology is that an additional step of separating the derivatized solute from the diluted induction solution is required in order to continuously produce the production water.

In addition, in Korea, rainfall is intensively generated, and when the inflow of sewage water exceeds the capacity of the sewage system during rainfall, the overflow sewage water is overflowed from the sewage tank, It is a fact that it is released. Furthermore, as the water area and the solid load of the secondary settling tank increase, problems such as settling sludge flooding may occur. To cope with this problem, a storage tank is installed to temporarily store the sewage water generated in the sewage treatment plant, However, since the amount of overflow is large, the capacity of the storage tank becomes large, and there arises a problem of burdening site, construction cost, etc. for installing the storage tank.

KR registration 1286044 (2013.07.09)

In order to solve the above-mentioned problem, the present invention can reduce the amount of treated sewage water by concentrating the sewage water, produce reused water without further process for separating the induced solute from the diluted induction solution, Can be used as a fertilizer (fertilizer) in the fertilizer (water) of the fertilizer without any separate separation process. Therefore, it is possible to reduce the energy cost as compared with the reverse osmosis process, And a system for producing reused water from sewage that can protect groundwater and a method using the same.

In addition, the present invention aims to prepare an inducer which can be used in the production of reusable water from sewage on the basis of the composition of mixed fertilizer and use it as an inducing solution.

The present invention relates to a method of separating an inflow water flowing through a gill in a sewage treatment plant, which is connected to a front end or a rear end of a primary settling tank for primarily performing a settling process, A forward osmosis module; A first supply pipe connected to a first end of the forward osmosis module to supply a supply solution, a first discharge pipe connected to a second end of the forward osmosis module, A second supply pipe connected to the third end of the forward osmosis module for supplying the induction solution, a second discharge pipe connected to the fourth end of the forward osmosis module for discharging the induction solution, And the diluted induction solution passing through the inducing solution transfer section is usable as reusing water. The present invention provides a system for producing concentrated sewage and reusing water from sewage water.

The present invention provides a method for producing concentrated water from sewage, comprising the steps of: (a) countercurrently supplying the feed solution and the induction solution; (b) moving the fresh water contained in the feed solution through the forward osmosis membrane to the induction solution transfer section by the positive osmotic pressure phenomenon by the difference in concentration between the supplied feed solution and the induction solution; And (c) moving the concentrated feed solution to a treatment tank of the next step, wherein the removed fresh water is excluded, wherein the diluted induction solution is used as reclaimed water. Thereby producing concentrated sewage and reused water.

The system for producing concentrated sewage and reused water from the sewage according to the present invention reduces the amount of treated water by concentrating the sewage. By using the mixed fertilizer as the induction solution, the produced reused water does not need a separate separation step, Because it can be used as a fertilizer, it can save energy costs and protect the soil and groundwater with eco-friendly process.

1 is a process diagram showing a conventional reverse osmosis process and a normal osmosis process.
FIG. 2 is a process diagram showing a conventional normal osmosis process and a normal osmosis process according to the present invention.
3 is a diagram showing a typical sewage treatment system.
4 illustrates a system for producing reused water from sewage according to an embodiment of the present invention.
5 illustrates a system for producing reused water from sewage according to another embodiment of the present invention.
FIG. 6 is a graph showing changes in osmotic pressure according to concentration of an induction solution according to an embodiment of the present invention.
7 is a graph showing the osmotic pressure of each induction solution according to an embodiment of the present invention.
8 is a graph showing the osmotic pressure of the individual components, the sum of the individual components, and the osmotic pressure of the mixed fertilizer in the induction solution of the embodiment of the present invention.
9 is a graph showing a comparison between the osmotic pressure of the individual component and the osmotic pressure of the mixed fertilizer according to the concentration change of the mixed fertilizer in the induction solution of the embodiment of the present invention.
10 is a graph showing the pH of the induction solution according to an embodiment of the present invention.
11 is a graph showing the change in water permeation flux versus inductive solution when the supply solution of the embodiment of the present invention is FS-1.
FIG. 12 is a graph showing changes in water permeation flux versus induced solution for a supply solution of FS-2 according to an embodiment of the present invention. FIG.
FIG. 13 is a graph showing changes in water permeation flux versus inductive solution when the supply solution of the embodiment of the present invention is FS-3. FIG.
FIG. 14 is a graph comparing changes in water permeation flux of each of the inductive solutions when the supply solution of one embodiment of the present invention is FS-2 and FS-3.
15 is a graph showing an average water permeation flux according to an induction solution according to an embodiment of the present invention.
16 is a graph showing the average water permeation flux according to the supply solution according to one embodiment of the present invention.
FIG. 17 is a graph showing changes in the concentration factor according to the feed solution FS-1 of one embodiment of the present invention. FIG.
18 is a graph showing the change of the concentration factor according to the feed solution FS-2 of one embodiment of the present invention.
19 is a graph showing changes in the concentration factor according to the feed solution FS-3 of one embodiment of the present invention.
FIG. 20 is a graph showing the change in the concentration factor for each feed solution in one embodiment of the present invention. FIG.
FIG. 21 is a graph showing the change in the concentration factor of the induction solution according to one embodiment of the present invention. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

Hereinafter, as shown in the brief description of the drawings, a system for producing concentrated sewage and reused water from the sewage of the present invention will be described in detail with reference to FIGS. 1 to 21 and embodiments.

The present invention relates to a system for producing concentrated sewage and reused water from wastewater using a forward osmosis process with mixed fertilizer as an inducing solution.

Here, the reuse water means the treated water usually treated in the sewage treatment facility. The reusable water can be divided into the number of contents and the water for off-site water. The water in the intestines includes washing water, cooling water, cleaning water, drinking water, dilution water, intestinal water and other water. , Off-site other water, and off-site waterworks.

In addition, a forward osmosis (FO) process refers to a process in which a solute is melted at a concentration higher than the concentration of the feed solution solute on one side of the semipermeable membrane through which the solute can not pass, thereby inducing a higher osmotic pressure than the feed solution, 2B is a process diagram showing a process of extracting fresh water in a feed solution to the induction solution by using a forward osmosis membrane from a feed solution, and FIG. 2B is a flow chart showing a process of extracting fresh water from a feed solution to an induction solution through a semipermeable membrane. have.

4 to 5, the system for producing concentrated sewage and reused water from the sewage of the present invention is characterized in that the system for producing concentrated sewage and reused water from the sewage treatment plant includes a first settling tank 10 for firstly precipitating inflow water, A forward osmosis module 100 connected to the stage 11 or the rear stage 12 and divided into a feed solution movement section 120 and an induction solution movement section 130 by a regular osmosis membrane 110; A first supply pipe (210) connected to the first end (101) of the forward osmosis module (100) to supply a supply solution and a second supply pipe A first discharge pipe 220 connected to the first discharge pipe 220; A second supply pipe 310 connected to the third end 103 of the forward osmosis module 100 for supplying an induction solution and a second supply pipe 310 for discharging the induction solution, A second discharge pipe 320 connected to the second discharge pipe 104; And the diluted induction solution passing through the induction solution transfer section 130 can be used as reusing water.

In particular, the forward osmosis module 100 may be configured such that the supply solution supplied through the first supply pipe 210 with the inside of the osmosis membrane 110 therebetween is supplied to the forward osmosis module 100 And a flow-through channel is formed so that an inductive solution supplied through the second supply pipe 310 can be supplied to the normal osmosis module 100. [

More specifically, the forward osmosis process is performed in the forward osmosis module 100 through the supply of the supply solution and the supply of the flowing solution, and the supply solution is supplied to the forward osmosis module 100 through the first supply pipe 210 And the induction solution flows into the forward osmosis module 100 through the second supply pipe 310 at the same time. Accordingly, in the case of the normal osmosis module 100 provided with the osmosis membrane 110, a positive osmosis action occurs.

Herein, the constant osmotic membrane 110 must be continuously supplied with the induction solution at a predetermined concentration.

In addition, the osmosis membrane 110 provided in the forward osmosis module 100 is provided with an osmosis membrane having selective permeability. Specifically, the osmotic membrane is also referred to as a semipermeable membrane, and means a membrane having fine holes uniformly formed on the surface thereof and having a property of passing only a solvent.

Here, the positive osmosis membrane 110 may be composed of cellulose triacetate (CTA), thin film composite polyamide (TFC), or the like.

In addition, the feed solution is characterized in that one of the influent or effluent of the primary clarifier (10) is used.

Here, when the forward osmosis module 100 is connected to the front end 11 of the primary settler 10, the supply solution may use inflow water entering the primary settler 10, When the forward osmosis module 100 is connected to the rear end 12 of the tea settling basin 10, the supply solution may use effluent discharged from the primary settler 10.

In addition, the induction solution as a _{solute, NH 4 NO 3, NH 4} H 2 PO 4, (NH 4) 2 HPO 4, NH 4 HCO 3, (NH 4) 2 SO 4, Ca (NO 3) 2, K ₂ S ₂ O ₃ , KCl, KHCO ₃ , KNO ₃ , NH ₄ Cl, and the like.

More specifically, the induction solution solute includes a fertilizer composition, more preferably NH ₄ NO ₃ , KCl, (NH ₄ ) ₂ HPO ₄ and a mixed fertilizer prepared by mixing the same, Can be used.

The mixed fertilizer (Blend) was prepared by mixing NH ₄ NO ₃ , (NH ₄ ) ₂ HPO ₄ and KCl in the weight ratio w of nitrogen (N): phosphorus (P ₂ O ₅ ): potassium (K ₂ O) / w%) is from 21:15 to 18:15 to 18, but is not limited thereto.

The NH ₄ NO ₃ , (NH ₄ ) ₂ HPO ₄ and KCl have a weight ratio (w / w%) of nitrogen (N): phosphorus (P): potassium (K) of 21: 6 to 8: .

As an example, it can be used as an induction solution by preparing mixed fertilizer that can be used in a system for producing recycled water from sewage, based on mixed fertilizer composition mainly used in Jeju Island. The most commonly used fertilizer composition in Jeju is mixed fertilizer with a ratio of nitrogen (N): phosphorus (P ₂ O ₅ ): potassium (K ₂ O) 21:17:17 (w / w%)

The nitrogen (N), phosphorus (P ₂ O ₅ ), and potassium (K ₂ O) are nutrients that require relatively large amounts of crops among various essential elements required for growing crops and are likely to be scarce in the soil. Element. In particular, in the present invention, by using NH ₄ NO ₃ , (NH ₄ ) ₂ HPO ₄ and KCl as an inducing solution, the ratio of nitrogen, phosphorus, and potassium can be independently controlled. For example, the weight ratio (w / w%) of nitrogen (N), phosphorus (P ₂ O ₅ ), and potassium (K ₂ O) is adjusted by mixing NH ₄ NO ₃ , (NH ₄ ) ₂ HPO ₄ , (N: P: K = 21.0: 7.4: 14.1), which is prepared so as to be 21:17:17 by weight, can be used as an inducing solution, but the present invention is not limited thereto.

Here, the concentration of the inducing solution solute of the present invention is higher than the concentration of the supplying solution.

The first supply pipe 210, the second supply pipe 310, the first discharge pipe 220, and the second discharge pipe 320 are each provided with at least one pump.

3, the forward osmosis module 100 is installed in front of the primary clarifier 100 so that the sewage introduced from the conventional sewage treatment system uses the inflow water that enters the primary clarifier 10 through the gutter. Referring to FIG. 4, the first supply pipe 210 is connected to the gypsum and receives the sewage discharged from the gypsum (inflow water of the primary sedimentation tank) Can be used.

The first discharge pipe 220 is connected to the primary settler 10 and discharges the supplied solution to the primary settler 10 to be processed through the primary settler 10, .

The forward osmosis module 100 installed at the front end 11 of the primary settling tank 10 may further include an induction solution supply tank 300 for supplying the induction solution, The solution supply tank 300 is connected to the second supply pipe 310.

The inductive solution supplied from the inductive solution supply tank 300 may be discharged through the second discharge pipe 320 via the induction solution transfer section 130 of the forward osmosis module and used as reused water.

5, when the forward osmosis module 100 is installed at the rear end 12 of the primary clarifier 100, the first supply pipe 210 is connected to the primary clarifier 100, (The effluent of the primary clarifier) which is discharged from the primary clarifier and is used as a supply solution.

The first discharge pipe 220 may be connected to a biological reactor provided at the rear end of the primary clarifier 10 to discharge the supply solution to the biological reactor.

Here, the forward osmosis module 100 installed at the rear end 12 of the primary clarifier 10 may further include an induction solution supply tank 300 for supplying the induction solution, The solution supply tank 300 is connected to the second supply pipe 310.

The inductive solution supplied from the inductive solution supply tank 300 may be discharged through the second discharge pipe 320 via the induction solution transfer section 130 of the forward osmosis module and used as reused water.

In this case, the induction solution passing through the second discharge pipe 320 from the forward osmosis module 100 installed at the front end 11 or the rear end 12 of the primary settler 10 is used as a diluted induction solution , Fertilizer ingredient, it can be used by liquid fertilizer (fertigation, water supply of irrigation system, fertilizer mixed) without separate separation process, that is, it can be diluted with water, In addition to eliminating the need for an additional process for diluted derivatized solution separation, it can reduce energy costs compared to reverse osmosis processes and protect soil and groundwater through eco-friendly processes.

Particularly, in the present invention, the first supply pipe 210 for supplying the supply solution and the second supply pipe 310 for supplying the induction solution are installed at both ends of the forward osmosis module 100 in diagonal directions, And the inducing solution can flow countercurrently.

Here, the counterflow refers to a case where the direction of flow of two fluids is opposite in the case of heat transfer or material transfer between two fluids. In particular, in the present invention, the countercurrent flow of the feed solution and the inducing solution is higher than that of the cocurrent flow by making the osmotic pressure difference larger than that flowing in parallel, so that the feed solution and the inducing solution flow countercurrently.

In the system for producing concentrated sewage and reused water from the sewage according to the present invention having the above-described structure, the following process proceeds.

A method for producing concentrated sewage and reused water from sewage of the present invention comprises the steps of: (a) supplying the feed solution and the induction solution countercurrently; (b) moving the fresh water contained in the feed solution through the forward osmosis membrane to the induction solution transfer section by the positive osmotic pressure phenomenon by the difference in concentration between the supplied feed solution and the induction solution; And (c) moving the concentrated supply solution to a treatment tank of the next step by removing the moved fresh water, wherein the diluted induction solution containing the transferred fresh water is used as reusing water; .

More specifically, when the feed solution supplied from the front end 11 or the rear end 12 of the primary clarifier 10 and the flowing solution are countercurrently supplied, the forward osmosis process in the forward osmosis module 100 It proceeds.

At this time, the supply solution supplied through the first supply pipe 210 passes through the supply solution transfer section 120 and the induction solution supplied through the second supply pipe 310 passes through the induction solution transfer section 130, Accordingly, in the normal osmosis module 100 having the osmosis membrane 110, a positive osmosis action occurs.

In particular, in the case of the osmosis membrane 110 process, a constant concentration of the inducing solution must be continuously supplied.

As the forward osmosis process by the positive osmotic action proceeds, the sewage is concentrated and produced by the solute such as the salt that has not passed through the osmosis membrane 110, and is introduced into the treatment tank through the first discharge pipe 220 . At this time, the effect that the treated water of the sewage water is reduced can be obtained.

More specifically, when the feed solution passes through the forward osmosis module 100, moves to the next treatment tank through the first discharge pipe 220, and the sewage is concentrated to reduce the amount of treated sewage water, The concentration factor and the volume reduction ratio (VRR) of the sewage can be expressed as follows.

Where f _c is the concentration of the feed solution, V _o is the initial volume of the feed solution, and V _t is the volume of the feed solution after t hours.

Therefore, as the concentration factor becomes larger, the volume reduction rate becomes larger, so that the treated water amount of the sewage decreases.

On the other hand, fresh water in the sewage having passed through the osmosis membrane 110 is mixed with the induction solution to produce a diluted induction solution. The induction solution mixture is discharged from the osmosis module 100 through the second discharge pipe 320 And can be used as reused water. In particular, the diluted derivatized solution can be used as a liquid fertilizer.

When the forward osmosis module 100 is installed at the front end 11 of the primary clarifier 10, the supply solution may include, for example, a supernatant liquid in which the influent water of the primary clarifier 10 is allowed to stand for 20 to 40 minutes May be used. More preferably, the supernatant which has been allowed to stand for 30 minutes may be used, but is not limited thereto.

When the forward osmosis module 100 is installed at the rear end 11 of the primary clarifier 10, the supply solution may be, for example, a supernatant liquid obtained by allowing the effluent of the primary clarifier 10 to stand for 20 to 40 minutes May be used. More preferably, the supernatant which has been allowed to stand for 30 minutes may be used, but is not limited thereto.

In addition, the effluent of the primary clarifier 10 may be passed through a cartridge filter of 0.5 to 2 mu m, and more preferably, filtered through a 1 mu m cartridge filter may be used. no.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are intended to illustrate the contents of the present invention, but the scope of the present invention is not limited to the following examples. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

Examples were carried out in order to realize a positive osmosis process system using fertilizer as an inducing solution, which is used in the present invention.

A positive osmosis module was prepared to implement the system of the present invention. In this case, the forward osmosis module is a channel of a forward osmosis module having a feed solution (FS) and a draw solution (DS) of 110 mm (L) x 36 mm (W) Respectively.

The FO membrane was installed such that the activated layer was upward and the porous layer was downward so that the feed solution flowed to the top surface of the osmosis membrane and the induction solution flowed to the bottom of the osmosis membrane.

The osmosis membrane used in the embodiment of the present invention is a cellulose triacetate (CTA) flat membrane (OsMemTM CTA-ES) manufactured by HTI, and the membrane area is 3,960 mm ² . Table 1 shows the properties of the membranes used in this example.

Membrane type CTA (cellulose triacetate) with embedded polyether screen support Maximum operating temperature 71 ° C Maximum transmembrane pressure 70 kPa pH range 3 to 8 Maximum chlorine 2 ppm Cleaning guideline Use only cleaning chemicals approved force / CTA RO membranes

The feed solution was supplied to the positive osmosis module using a diaphragm pump (DWP-62163A, Moterbank, KOREA) and the induction solution was supplied using a gear pump (WT3000-1JA, Baoding Longer Precision Pump Co., Ltd., China) . A constant temperature chamber (M20, LAUDA, Germany) was used to keep the temperature of the forward osmosis module constant and the operation temperature was kept constant at 25 ± 1 ° C.

In addition, the system operation was performed by supplying 2 L each of the supply solution and the induction solution to the PE supply solution tank and the induction solution tank, respectively, and supplying them to the forward osmosis module using a pump. Both the feed solution and the induction solution were allowed to flow countercurrently at a constant flow rate of 500 ml / min, and the solution passed through the forward osmosis module was circulated to the feed solution and the induction solution tank, respectively. Table 2 shows the operating conditions of this embodiment.

Membrane material CTA (cellulose triacetate) Membrane area 3,960 mm ² Flow rate of FS and DS 500 mL / min Temperature 25 ± 1 ° C Initial volume of FS and DS 2L Flow direction of FS and DS Counter current Operation time 24hr

In this embodiment, a feed solution and an inducing solution were prepared. The supernatant (hereinafter referred to as FS-1) and the effluent from the primary clarifier were left for 30 minutes. The supernatant (hereinafter referred to as FS-2) and the primary clarifier effluent (Hereinafter referred to as " FS-3 ") was used.

NH ₄ NO ₃ , (NH ₄ ) ₂ HPO ₄ , KCl and mixed fertilizer were used as induction solutions. The mixed fertilizer at a rate such as fertilizer (21-17-17), the most widely used in _{Jeju, NH 4 NO 3, (NH} 4) 2 HPO 4 and using KCl each nitrogen (N): phosphorus ( (W / w%) of potassium (P ₂ O ₅ ): potassium (K ₂ O) was 21:17:17.

The induction solution was prepared by dissolving a single fertilizer or mixed fertilizer in deionized water. The concentration of the inducing solution was adjusted to ₂ mol / LH ₂ O. NH ₄ NO ₃ , (NH ₄ ) ₂ HPO ₄ and KCl used in this example were all reagents (Samchun co. Korea) having a purity of 99% or more.

The most important factor in the cleansing process is the osmotic pressure difference between the inducing solution and the feed solution. That is, the greater the difference in osmotic pressure between the feed solution and the induction solution, the greater the water permeation flux. Also, since the membrane used in the positive osmosis process has a different pH range depending on the material, it may cause deformation of the osmosis membrane when using the inducing solution and the supplying solution.

Therefore, osmotic pressure and pH of the derivatized solution were measured in this example. Here, the osmotic pressure and pH of the derivatized solution were calculated using Stream Analyzer 3.2 (OLI Systems Inc., Morris Plains, NJ, USA).

In this example, 1) measurement of the osmotic pressure change according to the concentration change of the induction solution, 2) osmotic pressure measurement of the induction solution of 2mol / L H2O concentration, 3) individual components for the mixed fertilizer of 2mol Blend / L H2O, Osmotic pressure of mixed fertilizer, 4) comparison of osmotic pressure of individual component osmotic pressure and osmotic pressure of mixed fertilizer according to concentration of mixed fertilizer, and pH of induction solution.

1) Measurement of osmotic pressure change according to concentration of induction solution

First, the osmotic pressure according to the concentration change of each induction solution used in the present invention was measured and shown in FIG.

As a result, it was found that the osmotic pressure was increased as the concentration of the inducing solution was increased.

2) Osmotic pressure measurement of induction solution of 2mol / LH ₂ O concentration

Figure 7 shows the osmotic pressure of the inductive solution when the concentration of the inductive solution was all kept constant at 2 mol / L H2O.

As a _{result, NH 4 NO 3, (NH} 4) 2 HPO 4, were osmolarity of KCl and mixed fertilizers (Blend) has appeared respectively 64.8 atm, 95.0 atm, 89.3 atm and _{65.4 atm, (NH 4) 2} HPO 4 >KCl>Blend> NH ₄ NO _{3 in that} order.

3) Osmotic pressure measurement of individual components, individual components and mixed fertilizers for 2mol Blend / LH ₂ O mixed fertilizer

When the mixed fertilizer was 2 mol Blend / LH ₂ O, the osmotic pressure of the individual components constituting the mixed fertilizer was compared with the osmotic pressure of the three component osmotic pressure sum (Sum) and the mixed fertilizer (Blend).

As shown in FIG. 8, osmotic pressures of NH ₃ NO _{3 of} 0.92 mol / L, (NH ₄ ) ₂ HPO _{4 of} 0.43 mol / L and KCl of 0.65 mol / L were 28.9 atm, 21.4 atm and 29.3 atm, The Sum is 79.6 atm. However, the osmotic pressure of 2 mol / LH ₂ O mixed fertilizer containing 0.92 mol of NH ₄ NO ₃ , 0.43 mol of (NH ₄ ) ₂ HPO ₄ and 0.65 mol of KCl was found to be less than 79.6 atm and 65.4 atm.

This is because in the case of mixed fertilizers, the osmotic pressure is reduced by the interaction between the dissolved ions.

4) Comparison of osmotic pressure and osmotic pressure of mixed fertilizer according to concentration of mixed fertilizer

FIG. 9 shows the comparison of the sum of the osmotic pressures according to the concentration of the mixed fertilizer and the sum of the three individual component osmotic pressures constituting the mixed fertilizer.

As a result, the osmotic pressure of the mixed fertilizer was lower than the sum of the osmotic pressure of the three components, as in the case of the 2 mol / LH ₂ O mixed fertilizer. These differences increased with increasing concentration of mixed fertilizer. This is because in the case of mixed fertilizers, the osmotic pressure is reduced by the interaction between the dissolved ions. These differences also increased with increasing concentration of mixed fertilizer.

5) pH of induction solution

FIG. 10 shows the calculated pH when the concentration of NH ₄ NO ₃ , (NH ₄ ) ₂ HPO ₄ , KCl and Blend was 2 mol / LH ₂ O. FIG.

As a result, the pHs of NH ₄ NO ₃ , (NH ₄ ) ₂ HPO ₄ , KCl and Blend were 4.9, 7.7, 6.9 and 7.7, respectively. As shown in Example 1, 3 to 8, all were within the pH tolerance range of the CTA-ES which is the positive osmosis membrane used in the examples.

In this example, when the system according to the present invention was installed at the front of the primary clarifier of the sewage treatment plant and the influent water from the primary clarifier of the Jeju sewage treatment plant was used as the feed solution, 2 mol / LH ₂ O concentration was measured for each induction solution.

FIG. 11 is a graph showing changes in water permeation flux according to the operation time for each induction solution prepared at the concentration of ₂ mol / LH ₂ O according to the influent of the primary settling water (feed solution: FS-1).

As a result, regardless of the type of inducing solution, the water permeation flux decreased with operating time, and the permeate fluxes of KCl and NH ₄ NO ₃ were almost similar. Blend, (NH ₄ ) ₂ HPO ₄ , respectively.

In this embodiment, when the system according to the present invention is installed at the rear end of the primary clarifier of the sewage treatment plant and the effluent and effluent filtrate from the primary clarifier of the Jeju sewage treatment plant are used as the feed solution, the induction solution prepared in Example 2 is used And the water permeate flux of each inducing solution having a concentration of 2 mol / LH ₂ O was measured.

12 is a graph showing changes in water permeation flux according to the operation time of each induction solution prepared at the concentration of ₂ mol / LH ₂ O according to the primary clarifier effluent (feed solution: FS-2).

As a result, water fluxes were decreased according to the operating time regardless of the type of induction solution. The order of KCl> NH ₄ NO ₃ >Blend> (NH ₄ ) ₂ HPO ₄ was obtained.

Next, FIG. 13 is a graph showing changes in water permeation flux according to the operation time of each induction solution prepared at the concentration of ₂ mol / LH ₂ O according to the filtrate of the primary clarifier effluent (feed solution: FS-3).

FIG. 14 is a graph comparing the graphs of FS-2 and FS-3 by induction solution.

As a result, water fluxes were decreased according to the operating time regardless of the type of induction solution. The order of KCl> NH ₄ NO ₃ >Blend> (NH ₄ ) ₂ HPO ₄ was obtained. In addition, when the feed solution was FS-3, it was found that the water flux was relatively high relative to FS-2.

In this Example, the average permeation flux was calculated after conducting the forward osmosis test as in Example 4 and Example 5 for 24 hours, and the average water permeation flux and the water permeability per feed solution (FS-1, FS-2 and FS-3) 15 and 16 show the average water permeation flux per inductive solution.

The supernatant (FS-1) and the effluent of the primary clarifier were left to stand for 30 minutes. The supernatant (FS-2) and the primary clarifier effluent were set to 1 The filtrate (FS-3) passed through a ㎛ cartridge filter and NH ₄ NO ₃ , (NH ₄ ) ₂ HPO ₄ , KCl and Blend of ₂ mol / LH ₂ O were used as induction solutions, respectively.

As a result, regardless of the type of the induction solution, the average value of the permeate flux was in the order of FS-3>FS-2> FS-1. In addition, the average water permeation flux for each inducing solution was in the order of KCl> NH ₄ NO ₃ >Blend> (NH ₄ ) ₂ HPO ₄ . This tendency was more pronounced when the quality of the feed solution was relatively good, such as FS-3.

The average water permeation flux values according to the feed solution and the induction solution are shown in Table 3.

FS-1 FS-2 FS-3 KCl 9.18 LMH 10.87 LMH 13.31 LMH NH ₄ NO ₃ 9.70 LMH 10.39 LMH 11.60 LMH Blend 5.60 LMH 8.85 LMH 10.35 LMH (NH _{4) 2} HPO ₄ 3.40 LMH 4.15 LMH 6.03 LMH

As described above in the above embodiment, using the experimental apparatus and the operating conditions, the feed solution and the induction solution are FS-2 and Blend, respectively, the operation time is 24 hr / day, and the membrane module is (OsMemTM CTA-ES) And the theoretical production amount of reused water was calculated when the membrane area was 16.5 m ² .

As a result, it was found that FS-2 and Blend were used as a feed solution and an induction solution, and 3.5 m ³ / day was produced when the membrane area was 16.5 m ² .

As a result, the components of the reclaimed water produced in the above reaction are about 21:17:17 by weight ratio of nitrogen (N ₂ ): phosphorus (P ₂ O ₅ ): potassium (K ₂ O) Is the composition ratio of the most used fertilizer in Jeju Island. Therefore, if the reused water produced in the above is diluted, it can be used as agricultural water or the like.

In this example, when the system according to the present invention was installed at the front of the primary clarifier of the sewage treatment plant and the influent water from the primary clarifier of the Jeju sewage treatment plant was used as the feed solution, 2 mol / LH ₂ O solution was measured by the concentration factor induced with a concentration of.

FIG. 17 is a graph showing changes in the concentration factor depending on the operation time of each induction solution prepared at the concentration of ₂ mol / LH ₂ O according to the influent of the primary clarifier (feed solution: FS-1).

As a result, the concentration factors were continuously increased with the operation time, and the concentration factors of KCl and NH ₄ NO ₃ were almost similar, followed by Blend, (NH ₄ ) ₂ HPO ₄ .

In this embodiment, when the system according to the present invention is installed at the rear end of the primary clarifier of the sewage treatment plant and the effluent and effluent filtrate from the primary clarifier of the Jeju sewage treatment plant are used as the feed solution, the induction solution prepared in Example 2 is used The concentrations of inducible solutions with concentrations of 2 mol / LH ₂ O were measured.

First, FIG. 18 is a graph showing changes in concentration factors according to the operation time of each induction solution prepared at a concentration of ₂ mol / LH ₂ O according to the primary clarifier effluent (feed solution: FS-2).

As a result, according to the operating time factor concentration was continuously _{increased, KCl> NH 4 NO 3>} Blend> (NH 4) appeared in the order of ₂ HPO _4.

Next, FIG. 19 is a graph showing changes in the concentration factor depending on the operation time of each induction solution prepared at the concentration of ₂ mol / LH ₂ O according to the filtrate of the primary clarifier effluent (feed solution: FS-3).

As a result, the concentration factors were continuously increased, followed by KCl> NH ₄ NO ₃ >Blend> (NH ₄ ) ₂ HPO ₄ .

In this example, the average concentration factors of FS-1, FS-2 and FS-3 were calculated and the concentration factor and the concentration of each solution The average concentration factors are shown in FIGS. 20 and 21. FIG.

The supernatant (FS-1) and the effluent of the primary clarifier were left to stand for 30 minutes. The supernatant (FS-2) and the primary clarifier effluent were set to 1 The filtrate (FS-3) passed through a ㎛ cartridge filter and NH ₄ NO ₃ , (NH ₄ ) ₂ HPO ₄ , KCl and Blend of ₂ mol / LH ₂ O were used as induction solutions, respectively.

As a result, the mean value of the concentration factor increases in the order of FS-3> FS-2> FS-1, which is the same trend as the water permeation flux, because the concentration factor depends on the water permeation flux.

In addition, the average concentration factors for each inducing solution were KCl> NH ₄ NO ₃ >Blend> (NH ₄ ) ₂ HPO ₄ . This tendency was more pronounced when the quality of the feed solution was relatively good, such as FS-3.

The mean concentration factor values for the feed and induction solutions are shown in Table 4.

FS-1 FS-2 FS-3 KCl 1.77 2.07 2.72 NH ₄ NO ₃ 1.86 1.97 2.23 Blend 1.36 1.73 1.97 (NH _{4) 2} HPO ₄ 1.19 1.25 1.40

As described above in the above examples, theoretical values of the volume reduction rate when the supply solution and the induction solution are FS-2 and KCl, respectively, were calculated according to Equation (2) using experimental equipment and operating conditions.

As a result, using a FS-2 and KCl in the feed solution and the solution was derived, f _c is was found that obtaining a volume reduction rate of 51.7% when 2.07 days.

In conclusion, based on the above example, it can be seen that by using the system of the present invention, the sewage can be concentrated and the sewage treatment amount transferred to the next treatment tank is reduced by 50% or more.

100: positive osmosis module
101: first end 102: second end
103: Third end 104: Fourth end
110: osmosis membrane
120: feed solution transfer section 130: induction solution transfer section
210: first supply pipe 220: first discharge pipe
300: induction solution supply tank
310: second supply pipe 320: second discharge pipe

Claims (8)

A forward osmosis membrane that is connected to a front end or a rear end of a primary sedimentation tank for primary infiltration of inflow water flowing through a gypsum of a sewage treatment plant, ;
A first supply pipe connected to a first end of the forward osmosis module to supply a supply solution, a first discharge pipe connected to a second end of the forward osmosis module,
A second supply pipe connected to the third end of the forward osmosis module for supplying the induction solution, a second discharge pipe connected to the fourth end of the forward osmosis module for discharging the induction solution, / RTI >
Characterized in that the amount of treated water in the downstream is reduced by the concentrated feed solution passing through the feed solution transfer section.
The method according to claim 1,
Wherein the feed solution is one of an influent or an effluent of the primary clarifier.
The method according to claim 1,
The induction solution as a _{solute, NH 4 NO 3, NH 4} H 2 PO 4, (NH 4) 2 HPO 4, NH 4 HCO 3, (NH 4) 2 SO 4, Ca (NO 3) 2, K 2 S ₂ O ₃ , KCl, KHCO ₃ , KNO ₃ , and NH ₄ Cl. The system for producing concentrated sewage and reused water from sewage is characterized in that it comprises at least one solute selected from the group consisting of K ₂ O ₃ , KCl, KHCO ₃ , KNO ₃ and NH ₄ Cl.
The method of claim 3,
The weight ratio (w / w%) of nitrogen (N ₂ ): phosphorus (P ₂ O ₅ ): potassium (K ₂ O) was determined using NH ₄ NO ₃ , KCl and (NH ₄ ) ₂ HPO ₄ A system for producing concentrated sewage and reused water from sewage characterized by being able to produce and use a mixture of 21:15 to 18: 15 to 18.
The method according to claim 1,
Wherein the first supply pipe, the second supply pipe, the first discharge pipe, and the second discharge pipe each include at least one pump, respectively, for producing concentrated sewage and reusing water from the sewage.
A system for producing concentrated sewage and reused water from sewage according to any one of claims 1 to 5,
(a) countercurrently feeding the feed solution and the inducing solution;
(b) moving the fresh water contained in the feed solution through the forward osmosis membrane to the induction solution transfer section by the positive osmotic pressure phenomenon by the difference in concentration between the supplied feed solution and the induction solution; And
(c) moving the concentrated supply solution to the treatment tank of the next step by removing the moved fresh water, using the diluted induction solution containing the transferred fresh water as reused water; ≪ / RTI > wherein the concentrated water is recycled.
The method according to claim 6,
Wherein the feed solution is a supernatant liquid in which the influent water of the primary clarifier is allowed to stand for 20 to 40 minutes, thereby producing concentrated sewage and reusing water having reduced treated water from the sewage.
The method according to claim 6,
Wherein the feed solution is one of a supernatant obtained by allowing the effluent of the primary clarifier to stand for 20 to 40 minutes or an effluent of the primary clarifier passing through a 0.5 to 2 mu m cartridge filter. ≪ / RTI >

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