TWI648226B - Method and system for wastewater reclaimation - Google Patents

Abstract

A wastewater regeneration method and system, the wastewater regeneration method comprising the steps of: filtering solids and oils from a wastewater source to produce a filtered water; directing heat from a hot air having an average temperature of 377 degrees Celsius directly or Directly guiding the filtered water to the filtered water to produce a heated water having an average temperature of 80 degrees Celsius; reducing the pH value of the heated hot water to less than 6, so that the ammonia element in the heated hot water is NH ₄ ⁺ The ionic state exists to generate a tempered water; and the tempered water is subjected to an evaporation coagulation process to produce a regenerated water.

Description

Waste water regeneration method and system

The present invention relates to a water treatment method and system, and more particularly to a wastewater regeneration method and system for water treatment of highly polluted wastewater.

In many industries, water is an indispensable material in the process. How to improve water utilization is an important issue. For example, in the steel industry, coal mine processing operations are often required to provide the raw coal char required for the iron making process. When making coal char, industrial wastewater (also known as coking wastewater) is usually produced. The original output contains a large amount of polluting impurities, which are processed through a series of processes to remove most of the impurities.

For example, the highly polluted coking wastewater that is consistently operated in steel mills or coking plants is industrial wastewater generated during coking, high-temperature carbonization, purification and by-product recovery. The water contains volatile phenols, polycyclic aromatic hydrocarbons, and oxygen and sulfur. Heterocyclic compounds such as nitrogen are chemical industrial wastewaters with high chemical oxygen demand (COD), high phenolic value and high ammonia nitrogen refractory treatment. There are three main sources: one is the residual ammonia-containing wastewater generated in the process of coal retorting and gas cooling, the water accounts for more than half of the total amount of coking wastewater; the other is the wastewater generated by purifying the gas, such as: cold gas and crude benzene separated water; The third is the tar, crude benzene refining process and other wastewater generated in the process. In fact, coking wastewater is a typical industrial wastewater containing microbial refractory organic compounds. Microbial refractory organics mainly include acridine, carbazole, biphenyl, terphenyl, etc. In contrast, easily degradable organic substances are mainly phenols and benzene. Class of compounds; and naphthalene, furan, pyrrole, carbazole are degradable organics.

At present, most of the coking fields at home and abroad use the traditional biological anaerobic treatment as the core coking wastewater treatment process, which is mainly divided into pre-treatment, biological treatment and advanced treatment. The pre-treatment mainly uses physical and chemical methods, such as degreasing, steam, Extraction dephenolization, coagulation sedimentation, filtration, etc.; biological treatment is commonly used A / O method, A ₂ / O method; advanced treatment including activated carbon adsorption method, activated carbon - biofilm method, ozone oxidation method and oxidation pond method, etc. . However, in addition to the high cost of installation, energy consumption and operation, and complicated operation, the existing method must improve the reverse osmosis recovery rate in a multi-stage design. Moreover, if the pollutants in the coking wastewater are separated into the gas phase by the stripping method, there are still cases of low processing efficiency, energy consumption and secondary pollution, which have yet to be solved.

In view of the above, it is necessary to provide a different method of recycling wastewater to solve the problems of the conventional technology.

An object of the present invention is to provide a method for regenerating waste water, which is to heat high-polluting wastewater, to prevent molecular water ammonia in the water from deteriorating the quality of the distilled water, and to regenerate the wastewater.

A second object of the present invention is to provide a wastewater regeneration system that heats highly polluted wastewater, prevents molecular water ammonia in the water from deteriorating the quality of the distilled water, and then regenerates the wastewater.

To achieve the above object, the present invention provides a wastewater regeneration method, which may include the steps of: filtering solids and oils from a wastewater source to produce a filtered water; and from a temperature of between 280 and 380 degrees Celsius The heat in the hot air is directly or indirectly guided to the filtered water to generate a heated water having an average temperature of 70 to 90 degrees Celsius; the pH of the heated hot water is reduced to less than 6, so that The ammonia in the hot water is present in the ionic state of NH ₄ ⁺ to produce a tempered water; and the tempered water is subjected to an evaporation coagulation process to produce a regenerated water.

In order to achieve the above object, the present invention further provides a wastewater regeneration system, which may include: a pre-treatment unit for filtering solids and oils from a wastewater source to produce a filtered water; a waste heat recovery unit, fluidly Coupling between a waste heat source of a steel plant and the pretreatment unit for directly or indirectly guiding heat from a hot air having an average temperature of 280 to 380 degrees Celsius to the filtered water to generate a The average temperature is a hot water of 70-90 degrees Celsius; a pH adjustment unit is fluidly coupled to the waste heat recovery unit for reducing the pH value of the heated water to less than 6, so that the heat is heated The ammonia in the water is present in the ionic state of NH ₄ ⁺ to generate a tempering water; and a distillation unit is fluidly coupled to the pH adjusting unit for passing the tempering water through an evaporation coagulation process to generate a Recycled water.

In one embodiment of the invention, the hot air may be one of a sintering process from a steel mill that cools the hot air.

In an embodiment of the invention, one of the tempering water may have a pH of less than or equal to 5.

In one embodiment of the invention, one of the tempering water may have a pH ranging from 4 to 5.

In an embodiment of the present invention, the wastewater source may be coking wastewater from a steel mill, and the coking wastewater is sequentially subjected to a steam treatment process, a biological anaerobic treatment process, a thin film biological reaction process, and an ozone advanced process. Processing.

In an embodiment of the invention, the filtered water can be a Y-type filter, a filter bag filter, a swirling heart filter, a metal mesh filter, a single media filter, a multi-media filter. Produced by a tube or a tube filter.

In an embodiment of the invention, the heat in the hot air can be directed by a gas-liquid heat exchanger.

In an embodiment of the invention, the heat in the hot air can be guided by a gas-liquid heat exchanger via a pure water and a heat-insulating line.

In an embodiment of the invention, the gas-liquid heat exchanger may be a shell-and-tube heat exchanger or a plate and fin fin heat exchanger.

In one embodiment of the invention, the evaporative condensation process can be carried out using a thin film distiller, a vapor compressor, a multi-stage flasher, a multi-effect distiller or an evaporative crystallizer.

1‧‧‧Pre-processing unit

2‧‧‧Waste heat recovery unit

21‧‧‧ gas-liquid heat exchanger

22‧‧‧ pure water container

23‧‧‧Insulation pipeline

3‧‧‧pH adjustment unit

4‧‧‧Distillation unit

S1‧‧‧Filter step

S2‧‧‧ Heat conduction steps

S3‧‧‧ tempering steps

S4‧‧‧Distillation step

Figure 1 is a block diagram of a system of a wastewater treatment system in accordance with an embodiment of the present invention.

Fig. 2 is a schematic view showing the flow of a wastewater treatment method according to an embodiment of the present invention.

Figure 3 is a graphical representation of the flux versus time for a thin film distillation system in accordance with an embodiment of the present invention.

Fig. 4 is a schematic view showing the conductivity of the inflowing and discharging water and the produced water of the coking wastewater by the thin film distillation method in the embodiment of the present invention.

Figure 5a is a schematic diagram showing the relationship between the ammonia component and the pH value in the examples of the present invention.

Figure 5b is a schematic representation of the distillation process of an embodiment of the invention.

In order to make the above and other objects, features and advantages of the present invention more obvious It is to be understood that the following detailed description of the preferred embodiments of the invention Furthermore, the directional terms mentioned in the present invention, such as upper, lower, top, bottom, front, rear, left, right, inner, outer, side, surrounding, central, horizontal, horizontal, vertical, longitudinal, axial, Radial, uppermost or lowermost, etc., only refer to the direction of the additional schema. Therefore, the directional terminology used is for the purpose of illustration and understanding of the invention.

Referring to FIG. 1 , the wastewater regeneration system of the embodiment of the present invention may include a pre-processing unit 1, a waste heat recovery unit 2, a pH adjustment unit 3, and a distillation unit 4. The pretreatment unit 1 and waste heat The recovery unit 2, the acid-base adjusting unit 3 and the distillation unit 4 may be fluidly coupled in sequence to perform a wastewater source processing operation, for example, the wastewater source may be a high pollution unique to a steel mill or a coking field. Coking wastewater can also be applied to other wastewater (such as high-tech, petrochemical or chemical ammonia-containing wastewater). Here, only the coking wastewater is illustrated as follows, but not limited to this.

Referring to FIG. 1, the pretreatment unit 1 is configured to filter solids (such as debris, leaves or suspended solids, etc.) from a waste water source and grease to produce a filtered water. Thereby, the back-end pumping clogging can be avoided, and the service life of the subsequent processing equipment can be prolonged to ensure the stability of the operation of the overall processing flow.

In an embodiment, the pre-processing unit 1 can be a Y-type filter, a filter bag filter, a swirling heart filter, a metal mesh filter, a single media filter, and a multi-media filter. Or a tube filter or the like, the type of the pretreatment unit 1 can be selected according to the actual application requirements and the average particle size analysis result of the suspended solids in the wastewater, and is not limited herein.

Referring to FIG. 1 , the waste heat recovery unit 2 can be fluidly coupled to a waste heat source (such as a cooling hot air source of a steel mill sintering process, not shown) and the pretreatment unit 1 for Heat from a hot air having an average temperature between 280 and 380 degrees Celsius (° C.) (e.g., preferably 377 degrees) is directed directly or indirectly to the filtered water to produce an average temperature of between 70 and 70 Celsius. A hot water up to 90 degrees (°C) (e.g., preferably 80 degrees).

It should be noted that the consistent operation of steelmaking plants or coking plants where coking wastewater is located inevitably has many waste heats during operation. If the waste heat is not used properly, it will not only increase the ambient temperature, but also other energy sources. The above water source is heated to facilitate the subsequent treatment process. Therefore, using the cooling hot air of the steel mill sintering process as a heat source can be greatly Improve the efficiency of waste heat reuse during steel mill operations, while avoiding additional energy consumption costs during heating.

In an embodiment, the waste heat recovery unit 2 may include a gas-liquid heat exchanger 21, such as: the gas-liquid heat exchanger 21 may be a shell-and-tube heat exchanger or a plate and fin fin heat exchanger. The gas-liquid heat exchanger 21 can be fluidly coupled to the pH adjustment unit 3; or the waste heat recovery unit 2 can further include a pure water container 22 and a heat retention tube 23, which can be The liquid-liquid heat exchanger 21 is fluidly coupled to the heat-insulating tube 23, and the heat-insulating tube 23 is fluidly coupled to the pH-adjusting unit 3, but not limited thereto. The gas-liquid heat exchanger 21 can also fluidly couple the waste heat source with the pre-processing unit 1, and the coupling manner thereof can be understood by those of ordinary skill in the art.

Referring to FIG. 1 , the pH adjustment unit 3 can be fluidly coupled to the waste heat recovery unit to reduce a pH value of the heated water to less than 6, so that the ammonia element in the heated water is NH. _{The 4} ⁺ ionic state exists to produce a tempered water. Thereby, the ammonia gas in the NH ₃ molecular state in the water can be prevented from deteriorating the water quality, thereby improving the water quality of the reclaimed water, thereby expanding the use of the water and improving the water utilization rate.

Referring to FIG. 1, the distillation unit 4 is fluidly coupled to the pH adjustment unit for passing the tempering water through an evaporation condensation process to generate a reclaimed water.

In one embodiment, the distillation unit 4 can be a thin film distiller, a vapor compressor, a multi-stage flash evaporator, a multi-effect distiller or an evaporative crystallizer, etc., and the distillation unit 4 is only the film here. The distiller is described as an example, but not limited thereto.

In addition, the wastewater regeneration system of the above embodiment of the present invention can be applied to the wastewater regeneration method of the embodiment of the present invention, which is illustrated below, but not limited thereto.

Referring to FIG. 2, the wastewater regeneration system of the embodiment of the present invention may include: a filtration step S1, a thermal conduction step S2, a tempering step S3, and a distillation step S4, as shown in FIG. An example is as follows: In the filtering step S1, solids and fats from a coking wastewater can be filtered to produce a filtered water.

In one embodiment, the coking wastewater may be coking wastewater produced by a steel plant, and the coking wastewater is sequentially subjected to a steam treatment process, a biological anaerobic treatment process, and a film. Biological reaction process and an advanced process of ozone.

In an embodiment, the filtered water can be a Y-type filter, a filter bag filter, a swirling heart filter, a metal mesh filter, a single media filter, a multi-media filter or a A tubular filter is produced.

In the heat conducting step S2, heat from a hot air having an average temperature between 280 and 380 degrees Celsius may be directly or indirectly guided to the filtered water to generate an average temperature between 70 and 90 degrees Celsius. One is affected by hot water.

In an embodiment, the hot air may be one of a sintering process from a steel mill to cool the hot air; the heat in the hot air may be a gas-liquid heat exchanger 21 (eg, the gas-liquid heat exchanger may be a shell) A tubular heat exchanger or a plate and fin fin heat exchanger is guided into the filtered water.

In an embodiment, the heat in the hot air can be guided by the gas-liquid heat exchanger 21 through the pure water in a pure water container 22 and a heat retention line 23, so that the pure water becomes a hot water. In order to transport the hot water, for example, the heat of the sintering cooling hot air is transmitted to the pure water in the hot water system by using a heat exchanger, and the pure water after the endothermic heat is transferred to the treated wastewater by the heat exchanger (for example) The filtered water) is heated and heated by the treated wastewater, and then adjusted to the pH value to enter the thin film distillation system to produce reclaimed water. Among them, the above heat conduction process can be adopted in an appropriate manner according to actual needs. Thereby, the efficiency of waste heat reuse in the factory (such as a steel mill) can be greatly improved, and the energy loss in the subsequent distillation process can be reduced.

In the quenching and tempering step S3, a pH value of the heated water can be reduced to less than 6, so that the ammonia in the hot water is present in an ionic state of NH ₄ ⁺ to produce a tempered water. Thereby, the ammonia which must be present in the coking wastewater can be converted into an ionic state of NH ₄ ⁺ to prevent the ammonia of the NH ₃ molecular state from passing through the filter membrane in the subsequent distillation process, thereby causing the water quality to deteriorate. Improve water quality and water treatment.

In an embodiment, the adjustment of the pH value can be performed by using a fixed point or feedback control method, such as: applying an agent to adjust the pH value in the water, the agent can be a low concentration organic acid such as a suitable concentration, such as: 20 Up to 30% hydrochloric acid or 80 to 95% sulfuric acid.

In one embodiment, the pH value of the tempering water may be less than or equal to 5, for example, one of the tempering water may have a pH ranging from 4 to 5.

In the distillation step S4, the tempered water may be subjected to an evaporation coagulation process. To produce a reclaimed water. In this way, the thermal system can be selected in accordance with the waste heat generated by the continuous operation of the steel mill, and the vapor compression, multi-stage flashing and multi-effect can be evaluated according to the existing equipment, site, environment and waste heat quality. Distillation or a technique such as evaporation/crystallization or thin film distillation allows the above water to be evaporated during the treatment and then condensed into reclaimed water. Therefore, the wastewater regeneration process carried out by the above embodiments of the present invention can be directly integrated into an existing process (such as steel making or coking), has the advantages of easy implementation, energy saving, and the like, and can be applied to the contaminated wastewater treatment process in different fields.

In one embodiment, the evaporative condensation process can be carried out using a thin film distiller, a vapor compressor, a multi-stage flash evaporator, a multi-effect distiller or an evaporative crystallizer.

The following embodiments of the present invention are shown by way of example to assist in explaining the implementation of the wastewater reuse in the steel plant, but not limited thereto.

Example 1:

In this case, the wastewater source is the coking wastewater produced by a steel plant, the wastewater after steam, A/O biological deoxidation, membrane bioreactor and ozone advanced oxidation treatment; in addition, the Y-type filter can be used to block the wastewater. The leaves and living wastes; and the heat source may be the cooling hot air of the steelmaking process of the steel mill, the average temperature of the cooling hot air is 377 ° C, containing large heat and small variation; and, using heat exchangers and heat The water system supplies heat to heat the wastewater to 80 °C. In addition, hydrochloric acid and feedback control methods to adjust the pH value, reduce the pH value of wastewater to 4 ~ 5, reduce the NH ₃ content in water, and use a new thin film distillation technology with small footprint and high efficiency to distill wastewater Produced as recycled water.

In detail, the above-mentioned coking wastewater having a temperature of 80 ° C can be used as the influent water, and a long-term operation evaluation of a thin film distillation system is carried out under a vacuum operation pressure of 46 cmHg, and the flux of the thin film distillation system is A schematic diagram of the relationship of time can be as shown in Fig. 3, the thin film distillation system can be operated continuously for 8 days, and the flux is maintained at 5 to 12 L/m ² . h. In order to reduce the scaling and fouling of the film distillation system under long-term operation, the film distillation system uses hydrogen peroxide (H ₂ O ₂ ) and hydrogen chloride (HCl) for each operation for 3 days. The solution is washed to maintain the operational stability of the thin film distillation system.

Moreover, the conductivity of the inflow and outflow water and the produced water of the coking wastewater treated by the thin film distillation method can be as shown in Fig. 4, and the coking wastewater having a conductivity of 5,200 μS/cm is treated by thin film distillation under long-term operation. The water conductivity was 580 μS/cm and the salt rejection was 89%. The water quality of the coking wastewater was shown by the thin film distillation system of Table 1 below. The NH ₄ ⁺ of the raw wastewater was 261 mg/L and pH 7.61. After 1 day of operation in the thin film distillation system, the NH ₄ ⁺ of the produced water was 147 mg/L and pH. 9.50. It is speculated that ammonia in the coking wastewater forms ammonia gas (NH ₃ ) when the wastewater is heated, and passes through the hydrophobic film along with the water vapor, and is dissolved again into the produced water (ie, reclaimed water) during condensation, so that the produced water contains NH ₄ ⁺ and is lowered. Desalination performance of thin film distillation (as shown in Figure 5a). In addition, in addition to ammonia gas, the thin film distillation system can effectively remove organic matter, suspended solids (SS), and salts of coking wastewater.

As shown in Figure 5b, since the pH of the raw wastewater is less than 6, the NH ₃ content in the water can be reduced. Therefore, in order to reduce the influence of ammonia nitrogen in the raw wastewater, increase the water quality of the produced water, and reduce the NH ₄ ^{+ in the} produced water, the raw wastewater can be further reduced. The pH is 4~5 to ensure that the coking wastewater does not pass NH ₃ with water vapor through the hydrophobic film after heating, and is re-incorporated into the produced water upon condensation. As shown in Table 1 above, the concentration of NH ₄ ⁺ in the above-mentioned produced water was 48.4 mg/L, and it was confirmed that the ammonia-containing wastewater was treated by the thin film treatment technique, and the pH of the raw water was adjusted to be <5 in order to effectively remove NH ₄ ⁺ from the water.

Example 2:

In this case, the wastewater source is the coking wastewater produced by a steel plant, the wastewater after steam, A/O biological deoxidation, membrane bioreactor and ozone advanced oxidation treatment; in addition, the Y-type filter can be used to block the wastewater. The leaves and living wastes; and the heat source may be the cooling hot air of the steelmaking process of the steel mill, the average temperature of the cooling hot air is 377 ° C, containing large heat and small variation; and, using heat exchangers and heat The water system supplies heat to heat the wastewater to 80 °C. In addition, hydrochloric acid and feedback control method to adjust the pH value, reduce the pH value of wastewater to 4.5, reduce the NH ₃ content in water, and use a new thin film distillation technology with small footprint and high efficiency to distill waste water. For regenerating water.

In detail, as shown in Table 2 below, in order to reduce the influence of ammonia gas on the water quality, adjust the coking wastewater to pH 4.5, the membrane distillation system is at a temperature of 80 ° C, the vacuum operating pressure is 55 and 65 cmHg, and the aeration operation is not performed. The fluxes are 3.6 and 4.5 L/m ² , respectively. h, the operating pressure is proportional to the flux, and the overall water production is 0.66~0.82 cubic meters/day (m ³ /day).

Further, when the vacuum operation pressure was 65 cmHg, the water sample was analyzed for water conductivity of 429 μS/cm, and the overall salt rejection was 95%.

In addition, in order to improve the water production efficiency, steam aeration and tank fluid internal circulation can be utilized to increase fluid turbulence. The results show that if the vacuum operating pressure is 55cm/Hg, the flux increases from 150NL/min to 450NL/min, and the flux of the thin film distillation system increases to 4.7~5.1L/m ² . h, the water production is 0.9 cubic meters / day (m ³ /day). Also, when the vacuum operating pressure is increased to 65 cmHg and the aeration rate is increased to 600 NL/min, the flux can be greatly increased to 5.9 L/m ² . h, the water production can reach 1.01 cubic meters / day (m ³ /day), and the water recovery rate is about 14%. Among them, the water quality analysis can be as shown in Table 3 below, the water conductivity is 25 μS/cm, and the salt rejection is >99.3%.

In the present embodiment, the above-described pre-processing unit 1, waste heat recovery unit 2, pH-adjusting unit 3, and distillation unit 4 perform the above-described filtration step S1, heat-conducting step S2, quenching step S3, and distillation step S4. The production of reclaimed water with low energy consumption and good quality has the advantages of energy saving and easy implementation, and can be applied to high-polluting wastewater in different fields, which is beneficial to further improve sewage treatment efficiency and cost.

The present invention has been disclosed in its preferred embodiments, and is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

Claims (20)

A method for regenerating wastewater, comprising the steps of: filtering solids and oils from a source of wastewater to produce a filtered water; directing or indirectly guiding heat from a hot air having an average temperature between 280 and 380 degrees Celsius Leading to the filtered water to produce a heated water having an average temperature between 70 and 90 degrees Celsius; reducing the pH value of the heated hot water to less than 6, so that the ammonia in the heated hot water is NH ₄ ⁺ ions The state exists to generate a tempered water; and the tempered water is subjected to an evaporation coagulation process to produce a reclaimed water. The method for recycling wastewater according to claim 1, wherein the hot air is one of a sintering process from a steel mill to cool the hot air. The method for recycling wastewater according to claim 1, wherein the tempering water has a pH value of less than or equal to 5. The method for recycling wastewater according to claim 3, wherein one of the tempering water has a pH ranging from 4 to 5. The method for recycling wastewater according to claim 1, wherein the wastewater source is from coking wastewater produced by a steel plant, and the coking wastewater is sequentially subjected to a steam treatment process, a biological anaerobic treatment process, and a thin film biological reaction. Process and an advanced process of ozone. The method for recycling wastewater according to claim 1, wherein the filtered water is filtered by a Y-type filter, a filter bag filter, a swirling heart filter, a metal mesh filter, and a single medium filter. Produced by a multi-media filter or a tube filter. The method for recycling wastewater according to claim 1, wherein the hot air is The heat is guided by a gas-liquid heat exchanger. The method for recycling wastewater according to claim 1, wherein the heat in the hot air is guided by a gas-liquid heat exchanger through a pure water and a heat insulating pipe. The method for regenerating waste water according to claim 7 or 8, wherein the gas-liquid heat exchanger is a shell-and-tube heat exchanger or a plate and fin fin heat exchanger. The method for regenerating waste water according to claim 1, wherein the evaporative coagulation process is carried out by a thin film distiller, a vapor compressor, a multistage flash evaporator, a multi-effect distiller or an evaporative crystallizer. A waste water regeneration system comprising: a pre-treatment unit for filtering solids and oils from a wastewater source to produce a filtered water; a waste heat recovery unit fluidly coupled to a waste heat source and the pretreatment unit Between the heat from a hot air having an average temperature between 280 and 380 degrees Celsius being directly or indirectly directed to the filtered water to produce an average temperature between 70 and 90 degrees Celsius a hot water; a pH adjustment unit fluidly coupled to the waste heat recovery unit for reducing a pH value of the heated water to less than 6, so that the ammonia element in the heated water exists in an ionic state of NH ₄ ⁺ And generating a tempering water; and a distillation unit fluidly coupled to the pH adjustment unit for passing the tempering water through an evaporation coagulation process to produce a reclaimed water. The wastewater recycling system according to claim 11, wherein the pretreatment unit is a Y-type filter, a filter bag filter, and a swirling separation. A filter, a metal mesh filter, a single media filter, a multi-media filter or a tube filter. The waste water regeneration system of claim 11, wherein the waste heat recovery unit comprises a gas-liquid heat exchanger fluidly coupled to the pH adjustment unit. The waste water regeneration system of claim 11, wherein the waste heat recovery unit comprises a pure water container and a heat insulation pipe, the pure water container being fluidly coupled to a gas-liquid heat exchanger and the heat insulation pipe. The heat retention line is fluidly coupled to the pH adjustment unit. The wastewater reclamation system of claim 13 or 14, wherein the gas-liquid heat exchanger is a shell-and-tube heat exchanger or a plate and fin fin heat exchanger. The wastewater recycling system of claim 11, wherein the distillation unit is a thin film distiller, a vapor compressor, a multi-stage flasher, a multi-effect distiller or an evaporative crystallizer. The wastewater recycling system according to claim 11, wherein the wastewater source is from coking wastewater produced by a steel plant, and the coking wastewater is sequentially subjected to a steam treatment process, a biological anaerobic treatment process, and a thin film biological reaction. Process and an advanced process of ozone. The wastewater recycling system of claim 11, wherein the hot air is one of a sintering process from a steel mill to cool the hot air. The wastewater regeneration system of claim 11, wherein the tempering water has a pH value of less than or equal to 5. The wastewater recycling system according to claim 19, wherein the quenching and tempering One of the waters has a pH range of 4 to 5.