Waste incineration wastewater resource treatment system and method

Abstract

The present application relates to waste water treatment technology, and in particular to a waste incineration waste water resource treatment system and method. The present application realizes waste incineration waste water treatment of different types, and realizes waste resourceization in the treatment process. The present application also reduces energy consumption and cost in the waste incineration waste water treatment process.

Description

Technical Field

[0001] This invention relates to wastewater treatment technology, specifically to a system and method for the resource-based treatment of wastewater from waste incineration. Background Technology

[0002] Currently, the main methods of municipal solid waste treatment and disposal are gradually shifting from landfilling, which is heavily polluting and difficult to locate, to incineration. Incineration is currently the most widely used method for municipal solid waste treatment. Fly ash from municipal solid waste incineration and leachate concentrate are the main secondary pollutants generated during the incineration process.

[0003] Among them, the disposal situation of incineration fly ash entering municipal solid waste landfills is becoming increasingly severe. Cement kiln co-processing has become a more widely used resource utilization method. The fly ash contains a high amount of soluble salts, mainly chloride salts, which need to be washed and dechlorinated with water to meet the conditions for cement kiln co-processing, thus generating a large amount of high-concentration saline wastewater.

[0004] The amount of concentrate produced during the treatment of landfill leachate is generally 30% to 40%, with very high salt content. It is usually used for lime pulping, which has a significant corrosive effect on the flue gas desulfurization equipment after pulping. Furthermore, the salt from the pulping and desulfurization process will re-enter the fly ash.

[0005] Membrane concentrate and fly ash washing wastewater contain large amounts of inorganic salts. In recent years, evaporation technology has attracted much attention as a water treatment process for treating high-salinity wastewater and has been widely used in the field of zero-discharge wastewater resource utilization. However, the evaporation equipment currently used in the industry all have their own shortcomings. For example, the most widely used MVR (Mechanical Vapor Recompression) process has poor operational stability. Even with the addition of hardness removal facilities at the front end, the operation is still not stable enough, and the cleaning frequency is high. On the other hand, the submerged combustion process has better operational stability than MVR, but the investment and operating costs are higher.

[0006] The patents CN112678903A (equipment and method for treating saline wastewater), CN217479253U (a humidification and dehumidification treatment device for high-salinity wastewater), and CN210885723U (a near-zero discharge treatment system for leachate from incineration plants) describe in detail the equipment configuration of the humidification and dehumidification system, the technical methods for treating high-salinity wastewater, and the technical methods for near-zero discharge of leachate from waste incineration plants. However, when applied to wastewater treatment in waste incineration plants, the technical solutions in these three patents do not involve the recovery of ammonia resources in the leachate, requiring the retention of ammonia resources in conjunction with the leachate treatment module in this application. The patent CN117486421A (a process and system for co-treatment of fly ash washing wastewater from waste incineration plant leachate stations) proposes a process and system for co-treatment of leachate and fly ash washing wastewater from waste incineration plants, but the A / O system set up in the leachate pretreatment unit degrades ammonia resources, resulting in a waste of ammonia resources.

[0007] The patent "A Method for Resource Recycling of High-Salt and High-Ammonia-Nitrogen Wastewater" (CN110697959A) proposes a method for recovering ammonia resources from high-salt and high-ammonia-nitrogen wastewater. The method involves concentrating ammonium salts in the wastewater through evaporation and absorbing the ammonia volatilized during the evaporation process with magnesium salts and phosphates to obtain a composite magnesium ammonium salt. However, when applied to the treatment of wastewater from waste incineration, the ammonia resources cannot be recovered in the form of ammonia water for denitrification of incineration flue gas.

[0008] The literature "Feasibility Study on Flue Gas Denitrification Using Ammonia Tail Gas from Leachate" analyzes the feasibility of using stripping / absorption processes to recover ammonia from leachate in waste incineration plants for flue gas denitrification. The stripping tower and absorption tower proposed in the literature do not have the inorganic salt concentration performance of humidification and dehumidification technology.

[0009] In addition, the current treatment methods generally treat the two types of wastewater separately, which results in high investment and operating costs and waste of resources. How to achieve stable treatment of waste incineration wastewater while realizing waste resource utilization under the premise of economic feasibility is an urgent problem to be solved. Summary of the Invention

[0010] To address at least one of the aforementioned problems in the prior art, this invention provides a waste incineration wastewater resource recovery treatment system and method. This invention achieves waste resource recovery during the treatment process while simultaneously treating different types of waste incineration wastewater; furthermore, it reduces energy consumption and costs in the waste incineration wastewater treatment process.

[0011] A waste incineration wastewater resource utilization treatment system includes: a fly ash washing module, a leachate treatment module, and a humidification and dehumidification module;

[0012] The humidification and dehumidification module includes a pH adjustment unit, a humidification unit, a dehumidification unit, a heat pump unit, an ammonia concentration unit, an organic matter removal unit, a crystallization unit, and a second reverse osmosis unit.

[0013] The outlet of the pH adjustment unit is connected to the inlet of the humidification unit; the circulating air outlet and circulating air inlet of the humidification unit are connected to the circulating air inlet and circulating air outlet of the dehumidification unit, respectively; the heat from the dehumidification unit is transferred to the heat pump unit; the heat from the heat pump unit is transferred to the humidification unit; the inlet of the organic matter removal unit is connected to the outlet of the humidification unit, and the outlet is connected to the inlet of the crystallization unit; the inlet of the ammonia concentration unit is connected to the outlet of the dehumidification unit, and the outlet is connected to the inlet of the second reverse osmosis unit; another inlet of the second reverse osmosis unit is connected to the outlet of the crystallization unit, and one outlet is connected to the inlet of the humidification unit.

[0014] The fly ash washing wastewater generated by the fly ash washing module and the membrane concentrate generated by the leachate treatment module enter the pH adjustment unit.

[0015] According to the waste incineration wastewater resource utilization system of the present invention, the fly ash washing module includes a washing unit and a solid-liquid separation unit;

[0016] The outlet of the water washing unit is connected to the inlet of the solid-liquid separation unit; the outlet of the solid-liquid separation unit is connected to the inlet of the pH adjustment unit.

[0017] According to the waste incineration wastewater resource utilization system of the present invention, the fly ash washing module further includes a drying unit; the outlet of the solid-liquid separation unit is connected to the inlet of the drying unit.

[0018] According to the waste incineration wastewater resource utilization treatment system of the present invention, the leachate treatment module includes an anaerobic unit, a suspended solids separation-ammonia retention unit, a sludge dewatering unit, an ultrafiltration unit, and a first reverse osmosis unit;

[0019] Among them, the outlet of the anaerobic unit is connected to the inlet of the suspended solids separation-ammonia retention unit; one outlet of the suspended solids separation-ammonia retention unit is connected to the inlet of the sludge dewatering unit, and the other outlet is connected to the inlet of the ultrafiltration unit; one outlet of the sludge dewatering unit is connected to the inlet of the ultrafiltration unit, and the other inlet is connected to the outlet of the ultrafiltration unit; one inlet of the first reverse osmosis unit is connected to the outlet of the ultrafiltration unit, and the other outlet is connected to the inlet of the pH adjustment unit.

[0020] This invention also provides a waste incineration wastewater treatment method using the above-mentioned waste incineration wastewater resource utilization system, comprising:

[0021] S1, the fly ash from waste incineration is washed by the fly ash washing module, and the resulting fly ash washing wastewater enters the humidification and dehumidification module;

[0022] S2, the landfill leachate enters the leachate treatment module, and successively undergoes anaerobic treatment to remove organic matter, suspended solids separation-ammonia retention treatment to separate suspended solids, resulting in high-ammonia filtrate, then undergoes ultrafiltration treatment to obtain ultrafiltration permeate, and reverse osmosis treatment to obtain membrane concentrate; the membrane concentrate is then transported to the pH adjustment unit;

[0023] S3, fly ash washing wastewater and membrane concentrate enter the pH adjustment unit to adjust the pH and obtain high-salt, high-ammonia-nitrogen wastewater; then enter the humidification unit; the high-salt, high-ammonia-nitrogen wastewater is heated by hot water output from the heat pump unit in the humidification unit and undergoes mass and heat transfer with the circulating air of the dehumidification unit.

[0024] Ammonia in high-salt, high-ammonia-nitrogen wastewater is stripped off and enters the circulating air with the water vapor, resulting in ammonia-containing, high-temperature, and high-humidity circulating air. This air then enters the dehumidification unit, where the water vapor in the circulating air is condensed, and the ammonia is absorbed into the condensate, resulting in ammonia-containing condensate. The heat in the condensate is then transferred to the heat pump unit. The dehumidified circulating air from the dehumidification unit is returned to the humidification unit.

[0025] Ammonia-containing condensate enters the ammonia concentration unit to obtain concentrated ammonia water and ammonia-removed condensate water; the ammonia-removed condensate water is then transported to the second reverse osmosis unit.

[0026] High-salt, high-ammonia-nitrogen wastewater is concentrated into ultra-concentrated water after being humidified by the humidification unit. It then enters the organic matter removal unit. After the organic matter is removed, the ultra-concentrated water enters the crystallization unit, where it solidifies and crystallizes, producing crystallized condensate and inorganic salt products. The crystallized condensate then enters the second reverse osmosis unit.

[0027] The ammonia concentration unit produces deammoniation condensate, and the crystallization unit produces crystallization condensate. These are then treated by the second reverse osmosis unit to produce reverse osmosis concentrate and purified water. The reverse osmosis concentrate is then returned to the humidification unit.

[0028] According to the waste incineration wastewater treatment method of the present invention, step S1 includes: washing the waste incineration fly ash in a water washing unit; the fly ash slurry after water washing enters a solid-liquid separation unit for solid-liquid separation treatment; and the fly ash water washing wastewater obtained from solid-liquid separation enters a pH adjustment unit.

[0029] According to the waste incineration wastewater treatment method of the present invention, step S2 includes: the landfill leachate first enters the anaerobic unit to remove most of the organic matter in the landfill leachate, obtaining leachate after organic matter removal; the leachate after organic matter removal enters the suspended solids separation-ammonia retention unit to separate suspended solids and high-ammonia filtrate after ammonia retention treatment; the separated suspended solids are transported to the sludge dewatering unit; the suspended solids and sludge generated by the ultrafiltration unit enter the sludge dewatering unit to obtain dewatered sludge with qualified moisture content and dewatered clear liquid; the generated dewatered clear liquid is returned to the ultrafiltration unit; the high-ammonia filtrate and the dewatered clear liquid generated by the sludge dewatering unit enter the ultrafiltration unit to generate sludge and ultrafiltration permeate; the generated sludge is transported to the sludge dewatering unit, and the ultrafiltration permeate is transported to the first reverse osmosis unit; the ultrafiltration permeate is treated in the first reverse osmosis unit to generate clear water and membrane concentrate; the generated membrane concentrate is transported to the pH adjustment unit.

[0030] This invention, by setting up a humidification and dehumidification module, can utilize the same set of humidification, dehumidification, and evaporation equipment to achieve the concentration of inorganic salts and the stripping and recovery of ammonia in high-salt and high-ammonia nitrogen wastewater during the same evaporation and condensation process. The leachate treatment module can retain ammonia resources, and the fly ash washing module can retain inorganic salt resources in the waste. The combination of these three modules fully realizes the resource-based treatment of wastewater from the waste incineration process, which can significantly simplify the process and reduce investment and operating costs.

[0031] The humidification unit in this invention has the same ammonia stripping / absorption performance as the dehumidification unit.

[0032] Compared with existing technologies, the beneficial effects of this technical solution are as follows:

[0033] (1) Optimize the treatment process: This technical solution treats the two different types of wastewater generated during the waste incineration process through the same process technology, replacing the nitrification and denitrification biochemical process with a physical process, which simplifies the treatment process and reduces the treatment cost.

[0034] (2) Resource recycling: The inorganic salts separated during the humidification and dehumidification process can be sold to increase revenue after purification and refinement. The separated ammonia water can be used in the process of denitrification of flue gas from waste incineration. The generated clean water can be recycled as supplementary water for the process, truly realizing the resource-based treatment of wastewater.

[0035] (3) Improve treatment efficiency: The high-temperature clean water generated during the humidification and dehumidification process is used for fly ash washing water, which can significantly improve the washing efficiency of inorganic salts in the fly ash washing process, improve the fly ash washing efficiency, and reduce treatment costs. In addition, the suspended solids separation and ammonia preservation unit combined with the humidification and dehumidification unit recovers ammonia nitrogen in the form of ammonia water, avoiding the adverse effects of the complex process, strict reaction conditions, and high salt content of conventional ammonia treatment nitrification and denitrification technology. The overall treatment efficiency is greatly improved.

[0036] (4) Energy saving and consumption reduction: Equipped with a heat pump unit, it can recover the waste heat in the waste incineration process, recover the low-grade heat energy in the waste incineration process and convert it into high-grade heat energy for the humidification and dehumidification process, which can effectively save heat consumption.

[0037] (5) Improve operational stability: In the evaporation and concentration process of high-salt and high-ammonia nitrogen wastewater, the key evaporation and concentration equipment, the humidification and dehumidification tower, and its internal components that come into contact with the wastewater are all made of non-metallic materials, which are not easy to scale, are not afraid of high salt corrosion, and operate stably.

[0038] (6) Wide range of applications: The treatment method of the present invention can be applied not only to the wastewater generated in the waste incineration process, but also to the treatment of high-salt and high-ammonia nitrogen wastewater generated in other production processes, and has a wide range of application prospects. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the application process of the waste incineration wastewater resource utilization system according to an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the fly ash washing module structure of the waste incineration wastewater resource utilization system according to an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of the leachate treatment module of the waste incineration wastewater resource utilization system according to an embodiment of the present invention;

[0042] Figure 4This is a schematic diagram of the humidification and dehumidification module structure of the waste incineration wastewater resource utilization system according to an embodiment of the present invention.

[0043] Figure Labels

[0044] 100: Fly ash washing module; 101: Washing unit; 102: Solid-liquid separation unit; 103: Drying unit; 200: Leachate treatment module; 201: Anaerobic unit; 202: Suspended solids separation-ammonia retention unit; 203: Sludge dewatering unit; 204: Ultrafiltration unit; 205: First reverse osmosis unit; 300: Humidification and dehumidification module; 301: pH adjustment unit; 302: Humidification unit; 303: Dehumidification unit; 304: Heat pump unit; 305: Ammonia concentration unit; 306: Organic matter removal unit; 307: Crystallization unit; 308: Second reverse osmosis unit. Detailed Implementation

[0045] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0046] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0048] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0049] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0050] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, this embodiment of the invention provides a waste incineration wastewater resource utilization system, including: fly ash washing module 100, leachate treatment module 200, and humidification and dehumidification module 300.

[0051] The humidification and dehumidification module 300 includes a pH adjustment unit 301, a humidification unit 302, a dehumidification unit 303, a heat pump unit 304, an ammonia concentration unit 305, an organic matter removal unit 306, a crystallization unit 307, and a second reverse osmosis unit 308. The outlet of the pH adjustment unit 301 is connected to the inlet of the humidification unit 302. The circulating air outlet and circulating air inlet of the humidification unit 302 are respectively connected to the circulating air inlet and circulating air outlet of the dehumidification unit 303. The dehumidification unit 303... The heat is transferred to the heat pump unit 304; the heat from the heat pump unit 304 is transferred to the humidification unit 302; the inlet of the organic matter removal unit 306 is connected to the outlet of the humidification unit 302, and the outlet is connected to the inlet of the crystallization unit 307; the inlet of the ammonia concentration unit 305 is connected to the outlet of the dehumidification unit 303, and the outlet is connected to the inlet of the second reverse osmosis unit 308; another inlet of the second reverse osmosis unit 308 is connected to the outlet of the crystallization unit 307, and one outlet is connected to the inlet of the humidification unit 302.

[0052] Furthermore, the ammonia concentration unit 305 is also equipped with a concentrated ammonia water outlet.

[0053] Furthermore, crystallization unit 307 is also equipped with an outlet for inorganic salt products.

[0054] Furthermore, the crystallization unit 307 is heated by steam generated from the waste heat boiler of the incineration process.

[0055] Furthermore, the second reverse osmosis unit 308 is also equipped with a clean water outlet.

[0056] Furthermore, the fly ash washing wastewater generated by the fly ash washing module 100 and the membrane concentrate generated by the leachate treatment module 200 enter the pH adjustment unit 301.

[0057] Specifically, the humidification unit 302 includes a humidification packed tower, a humidification circulating water tank, a humidification circulating water pump, and a humidification heat exchanger. The humidification packed tower includes a humidification tower body, a humidification liquid distributor, humidification packing, and a humidification demister. All of its internal structural materials are non-metallic, with excellent resistance to salt and strong acid corrosion, providing sufficient conditions for direct contact mass and heat transfer between high-salt wastewater and air.

[0058] Specifically, the dehumidification unit 303 includes a dehumidification packed tower, a dehumidification circulating water tank, a dehumidification circulating water pump, and a dehumidification heat exchanger. The dehumidification packed tower includes a dehumidification tower body, a dehumidification liquid distributor, and dehumidification packing, providing sufficient conditions for the condensation of ammonia-containing high-temperature and high-humidity air.

[0059] Specifically, the heat pump unit 304 includes a heat pump unit, a heat pump circulating water tank, and a heat pump circulating water pump. The heat pump unit can recover low-grade heat energy at a lower temperature from the condensate generated by the dehumidification unit and convert it into high-grade heat energy for heating high-salt, high-ammonia nitrogen wastewater.

[0060] Specifically, the ammonia concentration unit 305 includes an ammonia concentration membrane, a transfer pump, and a circulation pump. The ammonia concentration membrane is a semi-permeable membrane made of a special material, which allows water in the ammonia-containing condensate to pass through the semi-permeable membrane, thereby obtaining a higher concentration of ammonia water.

[0061] like Figure 1 , Figure 2 and Figure 4 As shown, in some embodiments of the present invention, the fly ash washing module 100 includes a washing unit 101 and a solid-liquid separation unit 102; the outlet of the washing unit 101 is connected to the inlet of the solid-liquid separation unit 102.

[0062] The washing unit 101 is also equipped with an inlet for feeding in fly ash from waste incineration.

[0063] The washing unit 101 is also equipped with a clean water inlet.

[0064] The solid-liquid separation unit 102 is connected to the humidification and dehumidification module 300, specifically, the outlet of the solid-liquid separation unit 102 is connected to the inlet of the pH adjustment unit 301.

[0065] Furthermore, the fly ash washing module 100 also includes a drying unit 103; the outlet of the solid-liquid separation unit 102 is connected to the inlet of the drying unit 103.

[0066] The drying unit 103 is also equipped with a material outlet.

[0067] Furthermore, such as Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments of the present invention, the leachate treatment module 200 includes an anaerobic unit 201, a suspended solids separation-ammonia retention unit 202, a sludge dewatering unit 203, an ultrafiltration unit 204, and a first reverse osmosis unit 205. The outlet of the anaerobic unit 201 is connected to the inlet of the suspended solids separation-ammonia retention unit 202; one outlet of the suspended solids separation-ammonia retention unit 202 is connected to the inlet of the sludge dewatering unit 203, and the other outlet is connected to the inlet of the ultrafiltration unit 204; one outlet of the sludge dewatering unit 203 is connected to the inlet of the ultrafiltration unit 204, and the other inlet is connected to the outlet of the ultrafiltration unit 204; one inlet of the first reverse osmosis unit 205 is connected to the outlet of the ultrafiltration unit 204, and the other outlet is connected to the inlet of the pH adjustment unit 301.

[0068] Furthermore, the anaerobic unit 201 is also equipped with an inlet for the input of landfill leachate.

[0069] Furthermore, the sludge dewatering unit 203 is also provided with an outlet for discharging dewatered sludge.

[0070] Furthermore, the first reverse osmosis unit 205 is also equipped with a clean water outlet.

[0071] Figure 1 , Figure 2 , Figure 3 and Figure 4 The arrows in the diagram indicate the direction of material flow or heat transfer.

[0072] The waste incineration wastewater resource utilization system of this invention can be used for the resource utilization treatment of wastewater from the incineration process of municipal solid waste.

[0073] According to an embodiment of the present invention, the working process of the waste incineration wastewater resource utilization system is briefly described as follows:

[0074] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the waste incineration wastewater resource utilization system of this invention includes: fly ash washing module 100, leachate treatment module 200, and humidification and dehumidification module 300.

[0075] (1) Fly ash washing module 100 is used for washing and treating waste incineration fly ash to produce qualified fly ash and fly ash washing wastewater (high salt).

[0076] (2) Leachate treatment module 200, used to treat landfill leachate and produce clean water and membrane concentrate.

[0077] Specifically, the leachate treatment module 200 uses membrane treatment methods (e.g., membrane filtration) to treat landfill leachate.

[0078] Specifically, the clean water obtained after the leachate is treated by the leachate treatment module 200 can be reused in the fly ash washing module 100 for washing and treating the fly ash from waste incineration.

[0079] Specifically, after the landfill leachate is treated by the leachate treatment module 200, the ammonia resources are retained in the membrane concentrate for further recycling and processing in subsequent processes.

[0080] (3) Humidification and dehumidification module 300 includes pH adjustment unit 301, humidification unit 302, dehumidification unit 303, heat pump unit 304, ammonia concentration unit 305, organic matter removal unit 306, crystallization unit 307, and second reverse osmosis unit 308; humidification and dehumidification module 300 is used to simultaneously treat fly ash washing wastewater (high salt) and membrane concentrate.

[0081] Specifically, after being processed by the humidification and dehumidification module 300, the generated clean water can be reused in the fly ash washing module 100 for washing and treating waste incineration fly ash; the generated inorganic salt products can be sold externally; and the generated ammonia water can be reused in the flue gas denitrification system.

[0082] 1) The pH adjustment unit 301 is used to receive the fly ash washing wastewater generated by the fly ash washing module 100 and the membrane concentrate generated by the leachate treatment module 200, and mix the two to adjust the pH to obtain high-salt and high-ammonia nitrogen wastewater.

[0083] 2) The humidification unit 302 is used to receive the high-salt, high-ammonia-nitrogen wastewater output from the pH adjustment unit 301 and the reverse osmosis concentrate output from the second reverse osmosis unit 308. It uses the heat output from the heat pump unit 304 to heat and raise the temperature, and transfers mass and heat with the circulating air to deeply concentrate the inorganic salts in the wastewater to obtain ultra-concentrated water; and it strips the ammonia from the high-salt, high-ammonia-nitrogen wastewater and enters the circulating air with the water vapor to obtain ammonia-containing high-temperature and high-humidity circulating air.

[0084] 3) The dehumidification unit 303 is used to receive the ammonia-containing high-temperature and high-humidity circulating air output by the humidification unit 302, condense the water vapor in the circulating air, absorb the ammonia into the condensate, and obtain ammonia-containing condensate; and transfer the heat in the condensate to the heat pump unit 304.

[0085] 4) Heat pump unit 304 is used to convert low-grade heat energy in the condensate of dehumidification unit 303 into high-grade heat energy, and the high-grade heat energy is used to heat up the high-salt and high-ammonia nitrogen wastewater of humidification unit 302.

[0086] 5) The ammonia concentration unit 305 is used to receive the ammonia-containing condensate from the dehumidification unit 303, concentrate the ammonia in it into a certain concentration of concentrated ammonia water, and obtain ammonia-free condensate; the concentrated ammonia water is used for denitrification of incineration flue gas, and the generated ammonia-free condensate is transported to the second reverse osmosis unit 308.

[0087] 6) The organic matter removal unit 306 is used to treat the ultra-concentrated water produced by the humidification unit 302, removing most of the organic matter in it, and obtaining ultra-concentrated water after removing organic matter;

[0088] 7) Crystallization unit 307 is used to receive the ultra-concentrated water after organic matter removal from organic matter removal unit 306, and solidify and crystallize it to produce inorganic salt products; the required steam can be selected from the steam generated by the waste heat boiler of the incineration process, and the crystallized condensate is transported to the second reverse osmosis unit 308.

[0089] 8) The second reverse osmosis unit 308 is used to treat the ammonia concentrate water produced by the ammonia concentration unit 305 and the crystallization condensate water produced by the crystallization unit 307, and to produce reverse osmosis concentrate and water. The reverse osmosis concentrate produced by the second reverse osmosis unit 308 is returned to the humidification unit 302, and the produced water can be used for fly ash washing makeup water and recycled water.

[0090] Specifically, fly ash washing wastewater and membrane concentrate are mixed and then the pH is adjusted to 8-12, preferably 11.

[0091] Specifically, the temperature of the hot water output by the heat pump unit 304 can be between 80°C and 100°C, preferably 90°C.

[0092] Specifically, the temperature at which the material, namely high-salt and high-ammonia-nitrogen wastewater, is humidified in the humidification unit 302 can be selected between 65°C and 95°C, preferably 85°C.

[0093] Specifically, the air volume of the circulating air can be determined based on the volume of high-salt, high-ammonia-nitrogen wastewater to be treated, with the air volume (m³) as the unit. 3 / h) and water volume (m 3 The ratio of / h) can be selected between 4000:1 and 6000:1, preferably 5000:1.

[0094] Specifically, the high-salt, high-ammonia-nitrogen wastewater is concentrated into ultra-concentrated water with a salt content between 35% and 45% after passing through the humidification process of the humidification unit 302, preferably with a salt content of 40%.

[0095] Specifically, the resulting inorganic salt products have a moisture content of less than 10%.

[0096] Specifically, the dehumidification process temperature in the dehumidification unit 303 can be selected between 40℃ and 65℃, preferably 55℃.

[0097] Specifically, the concentration of ammonia-containing condensate (dilute ammonia water) can be selected between 0.5% and 1%, preferably 0.75%.

[0098] Specifically, ammonia-containing condensate (dilute ammonia water) is concentrated to a concentration of more than 10% and used in the flue gas denitrification process.

[0099] like Figure 1 , Figure 2 and Figure 4 As shown, in some embodiments of the present invention, the fly ash washing module 100 includes a washing unit 101 and a solid-liquid separation unit 102.

[0100] 1) The water washing unit 101 is used to wash and treat waste incineration wastewater, producing fly ash slurry and fly ash washing wastewater; the required clean water comes from the clean water produced by the humidification and dehumidification module 300 and the leachate treatment module 200.

[0101] 2) The solid-liquid separation unit 102 is used to separate the fly ash slurry after water washing, generating desalinated fly ash and fly ash washing wastewater; the generated fly ash washing wastewater is transported to the humidification and dehumidification module 300.

[0102] Furthermore, the fly ash washing module 100 also includes a drying unit 103 for drying the desalinated fly ash produced by the solid-liquid separation unit 102. The dried, qualified fly ash can be utilized as a resource.

[0103] like Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments of the present invention, the leachate treatment module 200 includes an anaerobic unit 201, a suspended solids separation-ammonia retention unit 202, a sludge dewatering unit 203, an ultrafiltration unit 204, and a first reverse osmosis unit 205.

[0104] 1) Anaerobic unit 201 is used to remove most of the organic matter in landfill leachate, resulting in leachate after organic matter removal;

[0105] 2) The suspended solids separation-ammonia retention unit 202 is used to separate the leachate after organic matter removal obtained from the anaerobic unit 201, to obtain suspended solids and high ammonia filtrate; the separated suspended solids are transported to the sludge dewatering unit 203;

[0106] 3) The sludge dewatering unit 203 is used to dewater the suspended solids separated by the suspended solids separation-ammonia retention unit 202 and the sludge produced by the ultrafiltration unit 204, to obtain dewatered sludge and dewatered clear liquid with qualified moisture content; the dewatered sludge is sent to sludge incineration disposal; the generated dewatered clear liquid is returned to the ultrafiltration unit 204;

[0107] 4) The ultrafiltration unit 204 is used to process the high ammonia filtrate produced by the suspended solids separation-ammonia retention unit 202 and the dewatered clear liquid produced by the sludge dewatering unit 203, producing sludge and ultrafiltration permeate; the produced sludge is transported to the sludge dewatering unit 203 and the ultrafiltration permeate is transported to the first reverse osmosis unit 205.

[0108] 5) The first reverse osmosis unit 205 is used to process ultrafiltration permeate to produce clean water membrane and concentrate; the produced membrane concentrate is transported to the humidification and dehumidification module 300; the produced clean water is used for fly ash washing and water reuse.

[0109] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, embodiments of the present invention also provide a waste incineration wastewater treatment method using the above-mentioned waste incineration wastewater resource utilization system, comprising:

[0110] S1, the fly ash from waste incineration is washed by the fly ash washing module 100, and the resulting fly ash washing wastewater enters the humidification and dehumidification module 300.

[0111] Specifically, the fly ash from waste incineration is washed in the washing unit 101; the washed fly ash slurry enters the solid-liquid separation unit 102 for solid-liquid separation treatment; the fly ash washing wastewater obtained from solid-liquid separation enters the pH adjustment unit 301 of the humidification and dehumidification module 300.

[0112] Specifically, different solid-liquid separation methods, such as centrifuges, screw presses, and filter presses, can be selected according to the properties of the fly ash. The desalinated fly ash produced after solid-liquid separation is dried to the required moisture content by the drying unit 103 and then utilized as a resource. The drying unit 103 can utilize the residual heat of the flue gas during the waste incineration process as a heat source, making full use of waste heat resources.

[0113] Specifically, fly ash from waste incineration is obtained from the incineration of municipal solid waste.

[0114] Specifically, the solid-liquid ratio can be determined based on the content of various inorganic salts in fly ash. For example, the solid-liquid ratio is (1:3)-(1:6) in g / mL.

[0115] S2, the landfill leachate enters the leachate treatment module 200, and is successively subjected to anaerobic treatment to remove organic matter, suspended solids separation-ammonia retention treatment to separate suspended solids, resulting in high ammonia filtrate, then ultrafiltration treatment to obtain ultrafiltration permeate, and reverse osmosis treatment to obtain membrane concentrate; the membrane concentrate is then transported to the pH adjustment unit 301 of the humidification and dehumidification module 300.

[0116] Specifically, the landfill leachate first enters the anaerobic unit 201 to remove most of the organic matter, resulting in leachate with organic matter removed. The leachate then enters the suspended solids separation-ammonia retention unit 202, where suspended solids and high-ammonia filtrate after ammonia retention treatment are separated. The separated suspended solids are transported to the sludge dewatering unit 203. The suspended solids and sludge produced by the ultrafiltration unit 204 enter the sludge dewatering unit 203 to obtain dewatered sludge with acceptable moisture content and dewatered supernatant. The dewatered sludge is then incinerated. The resulting supernatant... The purified water is returned to the ultrafiltration unit 204; the dewatered purified water produced by the high ammonia filtrate and sludge dewatering unit 203 enters the ultrafiltration unit 204 to produce sludge and ultrafiltration permeate; the produced sludge is transported to the sludge dewatering unit 203, and the ultrafiltration permeate is transported to the first reverse osmosis unit 205; the ultrafiltration permeate enters the first reverse osmosis unit 205 for treatment to produce purified water and membrane concentrate; the produced membrane concentrate is transported to the pH adjustment unit 301 of the humidification and dehumidification module 300; the produced purified water is used for fly ash washing makeup water and recycled water in the fly ash washing module 100.

[0117] Specifically, various methods can be selected for the separation of suspended solids, such as air flotation, flocculation sedimentation, and gravity sedimentation, while methods such as acid adjustment can be selected for ammonia preservation.

[0118] Specifically, landfill leachate is generated during the incineration of municipal solid waste.

[0119] S3, fly ash washing wastewater and membrane concentrate enter pH adjustment unit 301 to adjust pH and obtain high-salt, high-ammonia-nitrogen wastewater; enter humidification unit 302; the high-salt, high-ammonia-nitrogen wastewater is heated by hot water output from heat pump unit 304 in humidification unit 302 and undergoes mass and heat transfer with circulating air from dehumidification unit 303.

[0120] Ammonia in high-salt, high-ammonia-nitrogen wastewater is stripped off and enters the circulating air with the water vapor, resulting in ammonia-containing, high-temperature, high-humidity circulating air. This air then enters the dehumidification unit 303, where the water vapor in the circulating air is condensed, and the ammonia is absorbed into the condensate, resulting in ammonia-containing condensate (dilute ammonia water). The heat from the condensate is then transferred to the heat pump unit 304. The dehumidified circulating air from the dehumidification unit 303 returns to the humidification unit 302.

[0121] Ammonia-containing condensate (dilute ammonia water) enters the ammonia concentration unit 305 to obtain concentrated ammonia water and ammonia-removed condensate. The ammonia-removed condensate is then transported to the second reverse osmosis unit 308. High-salt, high-ammonia-nitrogen wastewater undergoes a humidification process in the humidification unit 302 and is concentrated into ultra-concentrated water, which then enters the organic matter removal unit 306. The ultra-concentrated water after organic matter removal enters the crystallization unit 307 for solidification and crystallization, producing crystallized condensate and inorganic salt products. The crystallized condensate enters the second reverse osmosis unit 308. The ammonia-removed condensate from the ammonia concentration unit 305 and the crystallized condensate from the crystallization unit 307 are treated in the second reverse osmosis unit 308 to produce reverse osmosis concentrate and purified water. The reverse osmosis concentrate is returned to the humidification unit 302. The purified water can be used for fly ash washing makeup water and recycled water.

[0122] Example 1

[0123] The waste incineration wastewater treatment method using the waste incineration wastewater resource recovery treatment system described in the above embodiments includes:

[0124] Step 1: 1000t / d of municipal solid waste incineration produces 30t / d of fly ash with a salt content of 30% (9t / d). The fly ash is washed with water at a solid-liquid ratio of 1:4, and then subjected to solid-liquid separation and drying to produce 50t / d of washed fly ash with a water content of 30%. 100t / d of fly ash washing wastewater with a salt content of 9% enters the humidification and dehumidification treatment process.

[0125] Step 2: 1000t / d of municipal solid waste is incinerated, producing 300t / d of leachate with an inorganic salt content of 2% (6t / d) and an ammonia nitrogen (calculated as NH3·H2O) concentration of 4000mg / L (1.2t / d). The leachate is treated using an anaerobic + suspended solids separation-ammonia retention + ultrafiltration + reverse osmosis process. The suspended solids and sludge dewatered are disposed of by incineration. 200t / d of the clean water after reverse osmosis treatment is used for reclaimed water and supplemental water for fly ash washing modules. 100t / d of the membrane concentrate produced by the reverse osmosis process enters the humidification and dehumidification process.

[0126] Step 3: 100 t / d of fly ash washing wastewater is mixed with 100 t / d of membrane concentrate. The mixture can be designed for humidification and dehumidification at a capacity of 10 t / h. After adjusting the pH of the mixture to 11, it is heated to 90℃ via a heat pump before entering the humidification process. The humidification process temperature is 85℃, and the mixture is then used with 50,000 m³ / h membrane concentrate. 3 The circulating air at a rate of / h is used for mass and heat transfer. The total amount of inorganic salts (dry basis) in the two wastewaters is 15t / d. After a humidification process, it is concentrated to 37.5t / d of ultra-concentrated water with a salt content of 40%. The ultra-concentrated water enters the organic matter removal and crystallization process. The crystallization condensate enters the reverse osmosis process, producing 16.67t / d of inorganic salt product with a water content of 10%.

[0127] Step 4: The water vapor and ammonia nitrogen carried out by the circulating air from the humidification process enter the dehumidification process. The dehumidification process temperature is 55℃, resulting in 162.5t / d of dilute ammonia water with a concentration of about 0.77%. The dehumidified circulating air returns to the humidification process, the dilute ammonia water enters the ammonia concentration process, the ammonia condensate enters the reverse osmosis process, and the dilute ammonia water is concentrated to a concentration of 10%, which is used for the flue gas denitrification process.

[0128] Step 5: The crystallization condensate and the ammonia removal condensate are mixed and enter the reverse osmosis process. The purified water after reverse osmosis is used for fly ash washing and replenishment. The excess purified water is treated as recycled water. The concentrate produced by reverse osmosis is returned to the humidification process.

[0129] The method described in this embodiment can effectively realize the resource-based treatment of waste incineration wastewater, reduce the energy consumption and cost of waste incineration wastewater treatment, and avoid secondary pollution during the waste incineration wastewater treatment process.

[0130] Due to the advanced nature of the technical solution of this invention, it has wide applications in waste incineration wastewater treatment and other industrial wastewater treatment fields. Firstly, this invention proposes a novel method for treating waste incineration wastewater, utilizing humidification and dehumidification technology to recover inorganic salts and ammonia from leachate membrane concentrate and fly ash washing wastewater, thus achieving waste resource recovery and helping to solve the problem of the inability to achieve waste resource recovery in existing waste incineration wastewater treatment technologies. Secondly, this invention can achieve the concentration of inorganic salts and the recovery of ammonia in the wastewater during the same humidification and dehumidification process, greatly improving treatment efficiency and reducing treatment costs. Therefore, this invention has broad application prospects and market demand in waste treatment plants, wastewater treatment plants, and environmental engineering fields.

[0131] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A waste incineration wastewater resource utilization system, characterized in that, include: Fly ash washing module, leachate treatment module, and humidification and dehumidification module; The humidification and dehumidification module includes a pH adjustment unit, a humidification unit, a dehumidification unit, a heat pump unit, an ammonia concentration unit, an organic matter removal unit, a crystallization unit, and a second reverse osmosis unit. The outlet of the pH adjustment unit is connected to the inlet of the humidification unit; the circulating air outlet and circulating air inlet of the humidification unit are connected to the circulating air inlet and circulating air outlet of the dehumidification unit, respectively; the heat from the dehumidification unit is transferred to the heat pump unit; the heat from the heat pump unit is transferred to the humidification unit; the inlet of the organic matter removal unit is connected to the outlet of the humidification unit, and the outlet is connected to the inlet of the crystallization unit; the inlet of the ammonia concentration unit is connected to the outlet of the dehumidification unit, and the outlet is connected to the inlet of the second reverse osmosis unit; another inlet of the second reverse osmosis unit is connected to the outlet of the crystallization unit, and one outlet is connected to the inlet of the humidification unit. The fly ash washing wastewater generated by the fly ash washing module and the membrane concentrate generated by the leachate treatment module enter the pH adjustment unit. The leachate treatment module includes an anaerobic unit, a suspended solids separation-ammonia retention unit, an ultrafiltration unit, and a first reverse osmosis unit connected in sequence. The suspended solids separation-ammonia retention unit is used to separate the leachate after anaerobic treatment to obtain a high-ammonia filtrate, and the membrane concentrate produced by the first reverse osmosis unit is delivered to the pH adjustment unit.

2. The waste incineration wastewater resource utilization system according to claim 1, characterized in that, The fly ash washing module includes a washing unit and a solid-liquid separation unit; The outlet of the water washing unit is connected to the inlet of the solid-liquid separation unit; the outlet of the solid-liquid separation unit is connected to the inlet of the pH adjustment unit.

3. The waste incineration wastewater resource utilization system according to claim 2, characterized in that, The fly ash washing module also includes a drying unit; the outlet of the solid-liquid separation unit is connected to the inlet of the drying unit.

4. The waste incineration wastewater resource utilization system according to any one of claims 1-3, characterized in that, The humidification unit includes a humidification packed tower, a humidification circulating water tank, a humidification circulating water pump, and a humidification heat exchanger; wherein, the humidification packed tower includes a humidification tower body, a humidification liquid distributor, humidification packing, and a humidification demister.

5. The waste incineration wastewater resource utilization system according to any one of claims 1-3, characterized in that, The dehumidification unit includes a dehumidification packed tower, a dehumidification circulating water tank, a dehumidification circulating water pump, and a dehumidification heat exchanger; wherein, the dehumidification packed tower includes a dehumidification tower body, a dehumidification liquid distributor, and dehumidification packing.

6. The waste incineration wastewater resource utilization system according to any one of claims 1-3, characterized in that, The heat pump unit includes a heat pump unit, a heat pump circulating water tank, and a heat pump circulating water pump.

7. The waste incineration wastewater resource utilization system according to any one of claims 1-3, characterized in that, The ammonia concentration unit includes an ammonia concentration membrane, a transfer pump, and a circulation pump.

8. A method for treating waste incineration wastewater using the waste incineration wastewater resource utilization treatment system according to any one of claims 1-7, characterized in that, include: S1, the fly ash from waste incineration is washed by the fly ash washing module, and the resulting fly ash washing wastewater enters the humidification and dehumidification module; S2, the landfill leachate enters the leachate treatment module, and successively undergoes anaerobic treatment to remove organic matter, suspended solids separation-ammonia retention treatment to separate suspended solids, resulting in high-ammonia filtrate, then undergoes ultrafiltration treatment to obtain ultrafiltration permeate, and reverse osmosis treatment to obtain membrane concentrate; the membrane concentrate is then transported to the pH adjustment unit; S3, fly ash washing wastewater and membrane concentrate enter the pH adjustment unit to adjust the pH and obtain high-salt, high-ammonia nitrogen wastewater; It enters the humidification unit; the high-salt, high-ammonia-nitrogen wastewater is heated in the humidification unit by the hot water output from the heat pump unit, and undergoes mass and heat transfer with the circulating air of the dehumidification unit. Ammonia in high-salt, high-ammonia-nitrogen wastewater is stripped off and enters the circulating air with the water vapor, resulting in ammonia-containing, high-temperature, and high-humidity circulating air. This air then enters the dehumidification unit, where the water vapor in the circulating air is condensed, and the ammonia is absorbed into the condensate, resulting in ammonia-containing condensate. The heat in the condensate is then transferred to the heat pump unit. The recirculated air dehumidified by the dehumidification unit is returned to the humidification unit; Ammonia-containing condensate enters the ammonia concentration unit to obtain concentrated ammonia water and ammonia-removed condensate water; the ammonia-removed condensate water is then transported to the second reverse osmosis unit. High-salt, high-ammonia-nitrogen wastewater is concentrated into ultra-concentrated water after being humidified by the humidification unit. It then enters the organic matter removal unit, and the ultra-concentrated water after removing organic matter enters the crystallization unit to solidify and crystallize, producing crystallized condensate and inorganic salt products. The crystallized condensate enters the second reverse osmosis unit; The ammonia concentration unit produces deammoniation condensate, and the crystallization unit produces crystallization condensate. These are then treated by the second reverse osmosis unit to produce reverse osmosis concentrate and purified water. The reverse osmosis concentrate is then returned to the humidification unit.

9. The waste incineration wastewater treatment method according to claim 8, characterized in that, Step S1 includes: washing the fly ash from waste incineration in a washing unit; the washed fly ash slurry entering a solid-liquid separation unit for solid-liquid separation treatment; the fly ash washing wastewater obtained from solid-liquid separation entering a pH adjustment unit; and / or, Step S2 includes: the landfill leachate first enters the anaerobic unit to remove most of the organic matter, resulting in leachate after organic matter removal; the leachate after organic matter removal enters the suspended solids separation-ammonia retention unit to separate suspended solids and high-ammonia filtrate after ammonia retention treatment; the separated suspended solids are transported to the sludge dewatering unit; the suspended solids and sludge produced by the ultrafiltration unit enter the sludge dewatering unit to obtain dewatered sludge with qualified moisture content and dewatered clear liquid; the generated dewatered clear liquid is returned to the ultrafiltration unit; the high-ammonia filtrate and the dewatered clear liquid produced by the sludge dewatering unit enter the ultrafiltration unit to produce sludge and ultrafiltration permeate; the generated sludge is transported to the sludge dewatering unit, and the ultrafiltration permeate is transported to the first reverse osmosis unit; the ultrafiltration permeate is treated in the first reverse osmosis unit to produce clear water and membrane concentrate; the generated membrane concentrate is transported to the pH adjustment unit.

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