KR100783356B1 - Method for the treatment of wastewater using freeze concentration - Google Patents

Abstract

As the present invention cools the wastewater, ice crystals composed of pure water are generated, and contaminants dissolved or suspended in the wastewater are supplied to the refining slurry, which is concentrated and concentrated around the ice crystals, to undergo a melting and separation process. The present invention relates to a wastewater treatment method and apparatus using a freeze-concentration method that allows the wastewater to be easily separated into purified effluent and concentrated wastewater.

To this end, the present invention comprises the steps of supplying the waste water into the freezing tube through the waste water supply pipe; Generating waste water supplied to the inside of the freezing tube by the refrigerant supplied through the refrigerant circulation passage as ice crystals on the freezing surface of the freezing tube; The ice crystals cooled on the frozen surface by the rotational driving of the scraper are scraped off and transferred to the slurry outlet along the spiral blade of the scraper; Introducing ice crystals in the slurry state discharged through the slurry outlet into the purifier; It provides a wastewater treatment method and apparatus using a freeze-concentration method comprising the step of separating the concentrated waste liquid and the effluent in purified pure water state through the melting process in the refiner.

Cryoconcentration, wastewater treatment apparatus and method, scraper, purifier, slurry, freezing tube

Description

Method and apparatus for wastewater treatment using freeze concentration method {Method for the treatment of wastewater using freeze concentration}

1 is a cross-sectional view showing a wastewater treatment apparatus using a freeze concentration method according to the present invention,

Figure 2 is a front view showing only the purifier of the wastewater treatment apparatus using the freeze concentration method according to the present invention,

3 is an explanatory diagram illustrating a process for delivering impurities in a crystal and an external fluid (mother liquor) for explaining the concentration phenomenon of the refiner in the wastewater treatment apparatus using the freeze concentration method according to the present invention;

Figure 4 is an actual picture of the refiner in the configuration of the wastewater treatment apparatus using the freeze concentration method according to the present invention

5 is a phase diagram of water soluble contaminants and water.

<Description of the symbols for the main parts of the drawings>

10 casing 12 freezing tube

14: freezing surface 16: refrigerant circulation passage

18a: Refrigerant supply port 18b: Refrigerant discharge port

20: wastewater supply pipe 22: slurry discharge port

32: scraper 34a: left flange

34b: right flange 35: bearing

36: drive motor 40: purifier

42: hollow case 44: concentrated waste liquid outlet

46: discharged water outlet 47: baffle plate

48: slurry inlet 50: first heat medium circulation passage

50a: first heat medium supply port 50b: second heat medium outlet

52: second heat medium circulation passage 52a: second heat medium supply port

52b: second heat medium outlet

The present invention relates to a wastewater treatment method and apparatus using a freeze-concentration method, and more particularly, by cooling the wastewater, ice crystals made of pure water are produced and contaminants dissolved or suspended in the wastewater are around the ice crystals. The present invention relates to a wastewater treatment method and apparatus using a freeze-concentration method, by supplying a concentrated slurry to a refiner to undergo a melting and separation process, thereby allowing the wastewater to be easily separated into purified effluent and concentrated waste liquid.

In general, wastewater is inevitably discharged by all industrial activities and human activities, so the treatment of the discharged wastewater will be very important in terms of environmental protection.

The ultimate goal of wastewater treatment is to meet the discharged water regulation by removing contaminants from factory wastewater, household wastewater, and sewage, so that physicochemical treatment, biological treatment, or a combination of these methods is based on various pollutant properties. It is introduced and used for the purpose of separation, oxidation and decomposition of organic and reducing substances, pH adjustment, removal of inorganic nutrients (mainly phosphorus or nitrogen compounds), treatment and disposal of solid slurries.

As a rule, wastewater treatment technologies include physicochemical treatments including flocculation and precipitation treatment, membrane separation, flotation, adsorption, ion exchange, oxidation and reduction, degassing, evaporation, biological treatments including biofilms, active slurries, anaerobic digestion, It is classified as a multi-stage advanced process in combination.

Generally, wastewater is treated by biological methods such as activated sludge process or anaerobic digestion for stability of treatment capacity and economic reasons, and it is difficult to expect effluent water quality only by biological treatment due to the characteristics of components contained in wastewater. Therefore, biological treatment and physicochemical methods such as flocculation and precipitation, chemical oxidation and reduction, and adsorption are used in consideration of the special situation of the sewage treatment plant.

Since organic wastewater is easily decomposed by microorganisms, more than 60% of biological wastewater is used, and since the 1980s, biological treatment has been limited, so physicochemical treatment has been performed in parallel and advanced treatment has been performed.

That is, wastewater treatment technology with high treatment efficiency has been established that meets emission standards by inducing primary decomposition of organic substances by anaerobic and aerobic biological treatment, and then performing coagulation, sedimentation, adsorption, and filtration.

In recent years, there has been an increasing number of cases that combine sterilization and decolorization through adsorption treatment with activated carbon, ultrafiltration, and ozone oxidation after flocculation and precipitation treatment.

On the other hand, inorganic wastewater is generally inexpensive flocculation and sedimentation treatment, and when soluble substances are included, filtration through oxidation, adsorption, ion exchange, membrane separation, and ozone oxidation is performed.

As a result, the basic framework of wastewater treatment is to convert soluble and suspending materials into insoluble suspending materials and to separate them into slurries and treated water after dehydration.

Therefore, recently, it is not necessary to treat adsorbents, flocculants, precipitates, products generated during oxidation and decomposition, and ozone, ultraviolet rays, and radiation treatment technologies which do not have their own oxidizing power and residual substances, and the coloring materials contained in organic and inorganic wastewater, It is widely applied in removing odorous substances and microorganisms.

The biological treatment method further includes a biofilm, activated slurry, contact aeration, anaerobic digestion, or a modification thereof. In this biological treatment method, anaerobic treatment is performed in one step, and a process for removing nitrogen and phosphorus is performed in two steps. Proceeds.

However, when the wastewater discharged is high and the main component contained in the wastewater has a high content as a toxic substance, the volume load must be kept low, thus requiring a large-scale treatment site and gradually decreasing the treatment efficiency.

The physical and chemical treatment methods include agglomeration and precipitation, ozone oxidation, filtration, activated carbon adsorption, Fenton oxidation, separation membrane, etc., and the chemical methods include agglomeration and precipitation or Fenton oxidation. It requires a large amount and requires attention to driving.

As an example of the physical treatment method, the reverse osmosis membrane (R / O) can be used to obtain a substantial performance, but the initial investment cost is high, and it is significant to pretreatment to prevent fouling by organic or inorganic materials. There is a problem that requires attention, and there is a case in which the facilities such as sand filtration, precision filtration at the front end of the reverse osmosis membrane (R / O), but in this case it is difficult to meet the water quality standards flowing into the reverse osmosis membrane (R / O), It is necessary to add a chemical facility for preventing the formation of scale and growth of microorganisms, and there is also a problem in that high power costs are required due to the high pressure operation of the pretreatment facility and the reverse osmosis membrane (R / O) facility.

On the other hand, if the main components contained in the wastewater, such as industrial wastewater, livestock wastewater, landfill leachate, etc. are hardly degradable, highly toxic, and high concentration, as described above, the treatment by biological methods combined with physicochemical methods is limited, in this case, For example, a high temperature heat treatment method such as incineration, wet oxidation, catalytic wet oxidation, and evaporation, and biological treatment technology by large dilution are further used.

However, in the case of the high temperature heat treatment method, the operating cost and installation cost of the wastewater treatment device are high due to the shortening of the life of the treatment device due to corrosion and excessive energy consumption due to latent heat of evaporation of water. The generation of secondary pollutants such as volatile organic compounds (VOCs) is emerging as a problem.

As is well known, the freeze concentration method utilizes the principle of separating and concentrating organic and inorganic matter contained in waste water into an unfrozen liquid while pure ice crystals are produced at temperatures below freezing point. It is known to be an excellent technique for the wastewater treatment and recycling techniques generated.

The principle of the freeze-concentration is based on thermodynamic solid-liquid equilibrium, although there are several types of solid-liquid equilibria that represent binary mixtures, but eutectic systems are not compatible with soluble organics (or inorganics). It is generally applied to mixtures of water, ie sewage water.

In this freeze-concentration method, due to the small dimension of the ice crystal lattice, organic matter (or inorganic) except hydrogen fluoride and ammonia cannot contain water as the crystal lattice, thus forming a solid solution with ice. This is impossible.

Theoretically, the aqueous solution of organic matter (or inorganic matter) is completely separated into 100% water and organic matter (inorganic matter) in one step, and thus, it is known that complete removal of contaminants contained in water by one step operation is possible. have.

5 shows a phase diagram of contaminants and water.

As mentioned above, most of the water-soluble contaminants and water form an eutectic system. When the influent wastewater in solution is cooled, ice crystals are generated past the solid-liquid equilibrium curve and the concentration of contaminants in the residual liquid increases. do.

Since the concentration of the water-soluble contaminant in the conventional wastewater is g / L level, the phase equilibrium of the actual water and the water-soluble contaminant is shown as a portion located close to the pure water as shown in FIG.

In this way highly purified effluents can be produced at temperatures operated only a few degrees below the freezing point of water, i.e. at low energy consumption.

Indeed, the operating temperature limit of the freeze-concentration is at the eutectic temperature reached by excessive cooling after ice crystals are produced from the feed wastewater, at which the water-soluble contaminants and water both solidify and do not separate.

Usually, the concentration of the aqueous solution is a common process in many industries.

The most commonly used process for concentrating aqueous solutions is evaporation, and instead of converting water into steam, freeze concentration concentrates the water and crystallizes the water below the freezing point of the solution.

Therefore, in theory, freeze-concentration by latent heat (76 kcal / kg), where water is phase-converted to ice, is one seventh of the energy consumption than evaporation or distillation by vaporization heat (540 kcal / kg), where water turns to steam. Level, which means that a high energy reduction effect can be expected when using freeze concentration in aqueous solution concentration.

In addition, there is no need for the addition of chemicals in the wastewater treatment, and since it operates at a low temperature, there is no corrosion problem and the durability is excellent, thus showing an excellent advantage in removing contaminants from the wastewater.

Accordingly, research on wastewater treatment by freeze-concentration has been continued in recent years by utilizing these advantages, and as an example, Korean Patent Registration No. 10-357289 (2002.10.07) discloses malignant wastewater such as industrial wastewater, landfill leachate, and livestock wastewater. A freeze-concentrating method and apparatus for processing have been disclosed. The freeze-concentrating device of this patent discloses a freezing surface, a crystallization tank, a crystal growth tank, a screw for transferring ice crystals raised by buoyancy to the top by centrifugal force and ice. It consists of a compressed air spraying device for washing attached contaminants and increasing turbulence at the interface, and a dissolution tank for dissolving the separated ice.

As another example, Korean Patent Publication No. 10-1990-12652 discloses a two-step countercurrent freeze-concentration system and method of an aqueous solution such as fruit juice, tea extracts that can be dissolved in coffee and cold water, milk, wine, beer, vinegar, and the like. As disclosed, the freeze-concentration system of this patent consists of a gradient column (2 units), a crystallizer (2 units), a washing column, a feeding tank, a heating unit, and a cooling unit (2 units). Cooling and freezing of the concentrate in a gradient column, separation of the resulting ice crystals and concentrates, removal of residual mother liquor from the ice crystal surface, and discharge of ice crystals.

More specifically, the first step gradient column freezes the solution to be concentrated (solid content: 2% to 20%) and produces ice crystals as a scraper located at the bottom of the apparatus, and the prepared ice crystals are transferred to the washing column. The residual mother liquor adhering to the ice crystal surface is removed and recovered as purified water (solid content: 0.01% to 0.05%).

Subsequently, the concentrate discharged from the one-stage gradient column is frozen, the ice crystals produced through the crystallizer are recycled to the one-stage gradient column, and after passing through a filter, the residual concentrate (solid content: ≒ 40%) is discharged, and then the second stage. By means of a scraper located at the bottom of the device, the residual mother liquor is transferred to the crystallizer, produced as secondary ice crystals, and fed to the first stage gradient column, and the ice crystals produced in the first stage gradient column are concentrated in the washing column. In countercurrent (countercurrent) contact with the solution, residual mother liquor on the surface of the ice crystals is removed.

As another example, Utility Model Registration No. 20-0221886 (2001.02.15) installs a cylindrical vertical shell-type ice maker with a conveyor and a water chamber on top of the wastewater desalination tank, and installs a dissolution tank adjacent to the side of the wastewater desalination tank to be connected to an ice maker. Pure water in the waste water is defrosted by heat exchange between the refrigerant in the refrigeration system and the waste water circulating in the ice maker, and the waste water is recovered and recycled in the wastewater freshwater tank, and the iced ice is separated into a liquid tank by solid-liquid separation by a conveyor installed at the bottom of the ice maker. Disclosed is a malignant wastewater treatment apparatus using a freeze concentration method.

However, these patents show that the freeze-concentration wastewater treatment technology removes residual mother liquor adhering to the surface of ice crystals to increase efficiency, wash columns to reduce the viscosity of the concentrate, and high supersaturation and short residence time for the preparation of fine ice crystals. This required high precision inclined column, separation of the produced ice crystals and the feed solution, and problems that are difficult to apply in the actual wastewater treatment process, and the above mentioned utility model technology is a vertical shell with conveyor and water chamber. There are many additional devices, such as ice makers and inclined separators, which make the configuration complicated.

Therefore, most of the advantages in energy consumption of ΔH _cry compared to evaporative latent heat (ΔH _vap ) are almost eliminated. Rather, it is consumed in parts other than the device that consumes actual crystallization heat such as washing column and compressed air blowing device. Due to the energy consumption, the economy and thermodynamic efficiency are very low.

The present invention has been studied in view of the above-mentioned problems, and does not require any countercurrent mass transfer device and additional device necessary to remove residual mother liquor attached to ice crystals. In order to provide a method and apparatus for treating wastewater using a freeze-concentration method, by supplying a slurry to a refiner and subjecting it to melting and separation, it is possible to effectively separate the discharged water and the concentrated wastewater from the fed wastewater by simple operation. There is this.

One embodiment of the present invention for achieving the above object is a casing in the form of a horizontal hollow tube; A freezing tube mounted to be spaced apart from the inner diameter surface of the casing, and the inner diameter surface being a freezing surface; A refrigerant circulation passage formed in a separation space between an inner diameter surface of the casing and an outer diameter surface of the freezing tube; A coolant supply and discharge port attached to a lower predetermined position of the casing to communicate with the coolant circulation passage; A scraper rotatably mounted in a state spaced apart from an inner diameter surface of the freezing tube; A left flange and a right flange mounted to seal one end and the other end of the casing and the freezing tube; A driving motor attached to an outer surface of the left flange and at the same time a rotating shaft thereof passes through the left flange and is connected to the shaft of the scraper; A wastewater supply pipe attached to one side of the casing to supply wastewater into the freezing pipe; A slurry discharge pipe attached to the other side of the casing and configured to discharge slurry wastewater in a slurry state; It provides a wastewater treatment apparatus using a freeze-concentration method comprising a purifier for melting the ice slurry wastewater discharged from the slurry discharge pipe to separate the concentrated waste liquid and the effluent of purified pure water.

In a preferred embodiment, the purifier is:

A hollow case in which a concentrated waste outlet is formed at one bottom and a purified discharge water outlet is formed at the bottom of the opposite side; A slurry inlet formed above the concentrated waste liquid outlet of the hollow case; A plurality of impurity induction plates arranged in a staggered arrangement from the concentrated waste liquid outlet to a position adjacent to the discharge water outlet in the hollow case; A first heat medium circulation passage having a space on an inner surface of the hollow case while having a circulation section from one side of the hollow case to the last impurity inducing plate; A second heat medium circulation passage having a space on an inner surface of the hollow case with a circulation section from the other side of the hollow case to the last impurity inducing plate; A first heat medium supply port and an outlet port attached to one side of the hollow case in communication with the first heat medium circulation passage; And a second heat medium supply port and an outlet port attached to the other side surface of the hollow case in communication with the second heat medium circulation passage.

In a preferred embodiment, the gap between the scraper and the freezing surface of the freezing tube is maintained at 10 to 20 mm.

In another preferred embodiment, the heat medium circulator including a compressor and a pump is connected between the first heat medium supply port and the outlet, and between the second heat medium supply unit and the outlet.

In another preferred embodiment, the refrigerant circulation port including a compressor and a pump is connected between the refrigerant supply port and the discharge port communicating with the refrigerant circulation passage.

Another embodiment of the present invention for achieving the above object is:

A first step comprising the apparatus of claim 1; A second step of supplying the wastewater into the freezing pipe through the wastewater supply pipe; A third step in which the wastewater supplied into the freezing tube by the refrigerant supplied through the refrigerant circulation passage is formed as ice crystals on the freezing surface of the freezing tube; A fourth step in which the ice crystals cooled on the frozen surface are scraped off and removed by the rotational driving of the scraper and transferred to the slurry outlet along the spiral blade of the scraper; A fifth step of introducing the slurry crystallized ice crystals discharged through the slurry discharge port into a refiner; It provides a wastewater treatment method using a freeze-condensation method characterized in that it comprises a sixth step of separating the concentrated waste liquid and the purified water effluent through the melting process in the refiner.

In a preferred embodiment, the slurry ice crystals supplied to the refiner are first melted by the heat medium flowing through the first heat medium circulation passage, separated into the concentrated waste liquid and the effluent, and the concentrated waste liquid is discharged through the concentrated waste liquid outlet. The effluent is characterized in that it is secondly dissolved by the heat medium flowing through the second heat medium circulation passage so that the remaining ice particles melt, and is discharged to the effluent outlet.

In another preferred embodiment, the concentrated waste liquid discharged to the concentrated waste liquid outlet is repeatedly recycled to the second, third, fourth, fifth, and sixth stages until the concentrated waste liquid is richer than the reference value.

At this time, the concentration is more than the reference value is characterized in that it further comprises the step of incineration of the concentrated waste liquid discharged to the concentrated waste liquid outlet.

As another preferred embodiment, when the effluent discharged through the effluent outlet includes residual waste liquid, the effluent is repeatedly recycled to the second, third, fourth, fifth and sixth stages until the residual waste liquid is removed. It is done.

Meanwhile, the refrigerant supplied to the refrigerant circulation passage is a mixture of ethylene glycol and water mixed in a weight ratio of 1: 1.

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

The present invention uses a scraper to scrape the ice crystals attached to the frozen surface to provide a driving force to produce a continuous ice crystal layer, while simultaneously producing an ice crystal slurry, and then to a portion of the bottom mounted purifier. The melt action induces turbulent flow at the interface to speed up heat and mass transfer, thereby transferring insoluble and soluble components contained in ice crystals to the external mother liquor (fluid), resulting in high separation concentration of pollutants and pure effluent. The point is to get one.

Here, look at in more detail the configuration for the freeze concentration device of the present invention.

1 is a cross-sectional view showing a wastewater treatment apparatus using a freeze concentration method according to the present invention, Figure 2 is a front view showing only a purifier of the wastewater treatment apparatus using a freeze concentration method according to the present invention, Figure 4 is Shows the actual picture of the purifier according.

As shown in FIG. 1, the wastewater treatment apparatus using the freeze concentration method according to the present invention has a horizontal process, and is provided with a casing 10 having a horizontal hollow tube.

The inner surface of the casing 10 is inserted into the freezing tube 12, the inner surface of which is the freezing surface 14, and the outer diameter of the freezing tube 12 and the inner diameter of the casing 10 are predetermined. The separation space is formed of a refrigerant circulation passage (16), and the refrigerant supply and outlet (18a, 18b) to communicate with the refrigerant circulation passage 16 at one side and the other predetermined position of the casing (10) Is formed.

In addition, the waste water supply pipe 20 is mounted to communicate with the freezing pipe 12 at one side of the casing 10, the slurry discharge port 22 is formed on the opposite side.

At this time, a refrigerant circulator (not shown) including a compressor and a pump is connected between the refrigerant supply and discharge ports 18a and 18b communicating with the refrigerant circulation passage 16 to supply the refrigerant to the refrigerant supply port 18a and the refrigerant. It serves to circulate through the circulation passage 16 and the refrigerant outlet 18b.

Here, the scraper 32 is rotatably inserted into the freezing tube 12, and the gap between the scraper 32 and the freezing surface 14 of the freezing tube 12 is maintained at 10 to 20 mm. The reason is that when ice crystals are formed on the freezing surface 14 of the freezing tube 12 by 10-20 mm or more, the scraper 32 can easily scrape and remove the ice crystals.

On the other hand, the upper and lower ends of the casing 10 and the freezing tube 12 are mounted with a left flange 34a and a right flange 34b.

A drive motor 36 is mounted on an outer surface of the left flange 34a, and a rotating shaft thereof is connected to the shaft of the scraper 32 by passing through the left flange 34a.

In addition, a bearing 35 is mounted on the right flange 34b as a supporting point for the opposite rotation axis of the scraper.

Here, looking at the configuration of the refiner for separating the ice slurry discharged from the slurry outlet into a concentrated waste liquid and effluent through the melting process as follows.

One side of the refiner is provided with a long hollow case 42 to the left and right, the bottom of one side of the hollow case is formed with a concentrated waste outlet 44 is discharged in the purified water state in the bottom of the opposite side is discharged Effluent outlet 46 is formed.

In addition, a slurry inlet 48 is formed above the concentrated waste liquid outlet 44 of the hollow case 42.

In addition, a plurality of impurity induction barriers 47 are attached to the inside of the hollow case 42, and the impurity induction barriers 47 are discharged from the discharge waste outlet 44 from the concentrated waste liquid outlet 44. Are arranged in a staggered arrangement up to a position adjacent to

In this case, the first heat medium circulation passage 50 forms a space on the inner surface of the hollow case 42 while having a circulation section from one side of the hollow case 42 to the last impurity inducing plate 47. At the same time the first heat medium supply port and the discharge port (50a, 50b) is formed on one side of the hollow case 42 to communicate with the first heat medium circulation passage (50).

In addition, the second heat medium circulation passage has a space on the inner surface of the hollow case 42 while having a circulation section from the other side of the hollow case 42 to the last impurity inducing plate 47. 52 is formed and second heat medium supply ports and outlets 52a and 52b are formed on the other side of the hollow case 42 to communicate with the second heat medium circulation passage 52.

At this time, between the first heat medium supply port (50a) and the discharge port (50b), and between the second heat medium supply unit (52a) and the discharge port (52b) heat medium circulator including a compressor and a pump to circulate the heat medium ( Shown) is connected.

Here, the wastewater treatment method of the present invention performed by the above configuration will be described in order.

First, waste water is supplied into the freezing pipe 12 through the waste water supply pipe 20.

The wastewater, that is, industrial wastewater, leachate, livestock wastewater, etc. containing hardly decomposable or toxic substances, should first be removed solid components that may cause mechanical problems, and contaminants from the wastewater by freeze concentration. The removal efficiency of is greatly affected by the concentration of contaminants, suspended solids content, etc. of the wastewater to be concentrated, so that it is preferable that the concentration of contaminants is 0.5 g / L or less for stable treatment of wastewater.

Subsequently, the wastewater is supplied into the freezing pipe 12 through the wastewater supply pipe 20 and is frozen in ice by the refrigerant supplied to the refrigerant circulation passage 16.

That is, the refrigerant supplied to the refrigerant circulation passage 16 is a mixture of ethylene glycol and water mixed in a weight ratio of 1: 1, and wastewater is formed on the freezing surface 14 of the freezing tube 12 by the refrigerant. To grow.

Next, when the ice crystal layer grows on the freezing surface 14 of the freezing tube 12 by 10-20 mm or more, it is scraped off by the scraper 32 rotating by the driving motor 36.

At this time, the scraper 32 is adjusted to a rotational speed of 50 ~ 200rpm that can be easily scraped off the ice crystal layer.

The ice crystals scraped off from the freezing surface 14 of the freezing tube 12 are then conveyed toward the slurry outlet 22 on the opposite side along the helical blade of the rotating scraper 32.

That is, the fine ice crystals removed from the freezing surface 14 of the freezing tube 12 promotes mass transfer between the residual concentrate and the ice crystals by turbulence formed by the rotation of the scraper 32, and gradually the slurry outlet ( To 22).

Next, the ice slurry wastewater discharged through the slurry outlet 22 is supplied to the slurry inlet 48 of the purifier 40.

Subsequently, the ice slurry wastewater introduced into the slurry inlet 48 by the heat medium supplied to the first heat medium circulation passage 50 is first melted and separated into a concentrated waste liquid and effluent.

At this time, the concentrated waste liquid is discharged through the concentrated waste liquid outlet 44, and the discharged water containing ice crystals continues to flow toward the baffle plate 47.

More specifically, the ice crystal slurry introduced into the refiner 40 maintained at a constant temperature is slowly partially melted, and then the mother liquor liquid partially melted with the surface of the ice crystals in a solution changed into some liquid state as shown in FIG. 3. By interfacial mass transfer between them, impurities contained in the ice crystals are transferred to the external mother liquor.

Subsequently, the ice crystals floating on the partially molten mother liquid surface flow along the baffle plate 47 in the refiner 40 to separate the purified ice crystals and impurities into the concentrated mother liquor, so that the remaining ice particles melt. After being melted secondly by the heat medium flowing through the heat medium circulation passage 52, the heat medium is discharged to the discharge water outlet 46.

In this way, the wastewater can be easily separated into concentrated wastewater and purified effluent by the wastewater treatment apparatus using a freeze-concentration method.

Preferably, the concentrated waste liquid discharged to the concentrated waste liquid outlet 44 is recycled through the waste water supply pipe 20 again if the concentration of the concentrated waste liquid is not higher than the reference value, while recycling the above process. If the concentrated waste liquid discharged to the concentrated waste liquid discharge pipe 44 is a rich concentration of more than the reference value is stored in a separate tank and then incinerated.

In addition, if the effluent discharged through the effluent discharge port 46 contains residual waste liquid, the waste water supply pipe 20 is re-supplied until the residual waste liquid is removed to recycle the above process, whereas If it does not contain residual waste liquid and purified pure water, it is discharged as it is.

On the other hand, according to the initial concentration of the contaminants contained in the feed wastewater and the water quality standards of the effluent, the wastewater treatment apparatus of the present invention can be disposed in a multi-stage series to perform the freeze-concentration process as described above, and the biological nature of the wastewater If the treatment is malignant enough, it can be used as a post-treatment process to increase the efficiency of pretreatment and contaminant removal in subsequent wastewater treatment processes.

Here, an experimental example in which the actual wastewater is treated by operating the wastewater treatment apparatus according to the present invention is as follows.

Experimental Examples 1 to 3

After supplying 5L of acetic acid wastewater (acetic acid concentration 1%) to the wastewater treatment apparatus using the freeze-concentration method according to the present invention, the acetic acid concentration of the effluent was measured.

Experimental Example 1 to Experimental Example 3, respectively, as the freezing conditions of the wastewater, as shown in Table 1 below, the slurry production temperature was applied differently.

As shown in Table 1, the yield (93.4%) was high in the case of Experimental Example 3, the acetic acid concentration (0.29%) of the effluent is rather high, the yield (84.7%) is good in the case of Experimental Example 2 Acetic acid concentration (0.07%) of effluent was the lowest.

As a result, it can be seen from Experimental Examples 1 to 3 that the wastewater treatment apparatus using the freeze-concentration method of the present invention can purify wastewater with effluent water below a reference value.

As seen above, according to the wastewater treatment method and apparatus using the freeze-concentration method according to the present invention provides the following advantages.

1) No necessary countercurrent mass transfer device or additional device used in the prior art is required to remove residual mother liquor attached to the ice crystals. You can.

2) Pure water and concentrated waste liquor can be separated and separated from the waste water at low cost simply through a one-step treatment without special equipment or equipment operation.

3) Finally, by treating wastewater economically and recycling purified water, if applied to chemical plants, enormous economic effects can be expected through environmental pollution prevention, wastewater treatment cost reduction, and resource recycling. It is possible to economically and effectively separate and concentrate malignant wastewater such as industrial wastewater containing landfill, landfill leachate, and livestock wastewater.

Claims (11)

A casing in the form of a horizontal hollow tube; A freezing tube mounted to be spaced apart from the inner diameter surface of the casing, and the inner diameter surface being a freezing surface; A refrigerant circulation passage formed in a separation space between an inner diameter surface of the casing and an outer diameter surface of the freezing tube; A refrigerant supply and discharge port attached to upper and lower predetermined positions of the casing to communicate with the refrigerant circulation passage; A scraper rotatably mounted in a state spaced apart from an inner diameter surface of the freezing tube; A left flange and a right flange mounted to seal one end and the other end of the casing and the freezing tube; A driving motor attached to an outer surface of the left flange and at the same time a rotating shaft thereof passes through the left flange and is connected to the shaft of the scraper; A wastewater supply pipe attached to one side of the casing to supply wastewater into the freezing pipe; A slurry discharge pipe attached to the other side of the casing and configured to discharge slurry wastewater in a slurry state; And a purifier for melting ice slurry wastewater discharged from the slurry discharge pipe and separating the concentrated waste liquid into effluent in purified pure water. The method according to claim 1, wherein the purifier: A hollow case in which a concentrated waste outlet is formed at one bottom and a purified discharge water outlet is formed at the bottom of the opposite side; A slurry inlet formed above the concentrated waste liquid outlet of the hollow case; A plurality of impurity induction plates arranged in a staggered arrangement from the concentrated waste liquid outlet to a position adjacent to the discharge water outlet in the hollow case; A first heat medium circulation passage having a space on an inner surface of the hollow case while having a circulation section from one side of the hollow case to the last impurity inducing plate; A second heat medium circulation passage having a space on an inner surface of the hollow case with a circulation section from the other side of the hollow case to the last impurity inducing plate; A first heat medium supply port and an outlet port attached to one side of the hollow case in communication with the first heat medium circulation passage; And a second heat medium supply port and a discharge port which are attached to the other side of the hollow case so as to be in communication with the second heat medium circulation passage. The wastewater treatment apparatus of claim 1, wherein a gap between the scraper and the freezing surface of the freezing tube is maintained at 10 to 20 mm. The wastewater treatment apparatus according to claim 2, wherein a heat medium circulator including a compressor and a pump is connected between the first heat medium supply port and the outlet, and between the second heat medium supply unit and the outlet. The wastewater treatment apparatus according to claim 1, wherein a refrigerant circulator including a compressor and a pump is connected between the refrigerant supply port and the discharge port communicating with the refrigerant circulation passage. A first step comprising the apparatus of claim 1; A second step of supplying the wastewater into the freezing pipe through the wastewater supply pipe; A third step in which the wastewater supplied into the freezing tube by the refrigerant supplied through the refrigerant circulation passage is formed as ice crystals on the freezing surface of the freezing tube; A fourth step in which the ice crystals cooled on the frozen surface are scraped off and removed by the rotational driving of the scraper and transferred to the slurry outlet along the spiral blade of the scraper; A fifth step of introducing the slurry crystallized ice crystals discharged through the slurry discharge port into a refiner; It provides a wastewater treatment method using a freeze-concentration method comprising the sixth step of separating into a concentrated waste solution and purified water effluent through the melting process in the refiner. The method according to claim 6, wherein the ice crystal in the slurry state supplied to the refiner is first melted by the heat medium flowing through the first heat medium circulation passage separated into the concentrated waste liquid and effluent, and then the concentrated waste liquid is discharged through the concentrated waste liquid outlet, The effluent is a wastewater treatment method using the freeze-concentration method characterized in that the second effluent by the heat medium flowing through the second heat medium circulation passage so that the remaining ice particles melt, and is discharged to the effluent outlet. delete delete The method according to claim 6 or 7, wherein if the discharged water discharged through the discharge water outlet includes the residual waste liquid is recycled to the second, 3, 4, 5, 6 steps until the residual waste liquid is removed A wastewater treatment method using a freeze concentration method characterized in that. The wastewater treatment method according to claim 6, wherein the refrigerant supplied to the refrigerant circulation passage is a mixture of ethylene glycol and water mixed at a weight ratio of 1: 1.

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