Laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation

Abstract

The present invention discloses a laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation, comprising a rooftop photovoltaic system, a laundry wastewater pretreatment system, a solar CPC-type dual-path preheating system, a thermoelectric composite agarose hydrogel layer membrane distillation system, and an ultraviolet disinfection system. The rooftop photovoltaic system is connected to the laundry wastewater pretreatment system, the solar CPC-type dual-path preheating system is connected to the thermoelectric composite agarose hydrogel layer membrane distillation system, the thermoelectric composite agarose hydrogel layer membrane distillation system is connected to the laundry wastewater pretreatment system, and the ultraviolet disinfection system is connected to the thermoelectric composite agarose hydrogel layer membrane distillation system. Through the mutual cooperation between multiple systems, efficient purification of campus laundry wastewater is achieved, so as to facilitate the recycling and reuse of campus laundry wastewater and avoid the pollution of campus laundry wastewater to rivers.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, in particular to a laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation. Background Art

[0002] 1. Rooftop photovoltaics

[0003] As an idle land resource, building rooftops are one of the important potential sites for the development of photovoltaic power generation. In 2021, the distributed photovoltaic power generation market, mainly based on building rooftop photovoltaics, accounted for more than 50% of the total photovoltaic market. Compared with other power generation methods, building rooftop photovoltaics not only improves land use efficiency and reduces land use costs, but also avoids the ecological interference caused by the construction of photovoltaic power stations. In addition, building rooftop photovoltaics have the characteristics of high deployment flexibility, strong local absorption capacity, high energy utilization efficiency, and low life cycle carbon emissions. In addition, the Ministry of Education, in the notice of the "Implementation Plan for the Construction of a Green and Low-Carbon Development National Education System", advocated the implementation of school building rooftop photovoltaics in areas with conditions to promote the integrated development of photovoltaics and buildings.

[0004] 2. Membrane distillation

[0005] The membrane distillation process utilizes a hydrophobic microporous membrane as the separation membrane, with the vapor pressure difference across the membrane serving as the driving force for the membrane separation process. Membrane distillation allows for the selective permeation of water vapor and the removal of non-volatile impurities from the water. Because the membrane used for membrane distillation is hydrophobic, the feed liquid and condensate are separated by the membrane during the membrane distillation process, preventing the aqueous solutions on either side from communicating with each other. However, heating the feed liquid creates a vapor pressure difference across the membrane, driving water vapor into the membrane pores and then from the feed liquid side to the condensate side. This is very similar to the evaporation, mass transfer, and condensation processes in conventional distillation.

[0006] 3. Mechanism of agarose hydrogel layer blocking surfactant

[0007] The high-water-content agarose hydrogel acts as a static water layer. Once the surfactant molecules contact the hydrogel surface, only the hydrophilic part is absorbed into the hydrogel, and the hydrophobic part is left outside the surface, thereby preventing the surfactant from further penetrating into the hydrogel layer. The surfactant will accumulate at the interface, thereby playing the role of protecting the hydrophobic layer of the distillation membrane.

[0008] Campus laundry wastewater contains significant amounts of pollutants such as nitrogen, phosphorus, surfactants (LAS), oil, and solid particles. Uncontrolled discharge can negatively impact river water quality, leading to eutrophication, algae blooms, and water blackening and odorization, damaging the aquatic ecosystem. Existing technologies for treating campus laundry wastewater are mostly decentralized, inefficient, and of poor quality. Furthermore, campus laundry wastewater is often concentrated, with a smaller volume than industrial wastewater. Purifying industrial wastewater using methods that are costly, therefore addressing campus laundry wastewater urgently requires solutions. Summary of the Invention

[0009] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0010] The technical problem to be solved by the present invention is how to efficiently solve the problem of purifying laundry wastewater on campus.

[0011] To solve the above technical problems, the present invention provides the following technical solutions: a laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation, which includes a rooftop photovoltaic system, a laundry wastewater pretreatment system, a solar CPC-type dual-path preheating system, a thermoelectric composite agarose hydrogel layer membrane distillation system and an ultraviolet disinfection system, wherein the rooftop photovoltaic system is connected to the laundry wastewater pretreatment system to generate an electricity supply system, the solar CPC-type dual-path preheating system is connected to the thermoelectric composite agarose hydrogel layer membrane distillation system to adjust the temperature of the thermoelectric composite agarose hydrogel layer membrane distillation system, the thermoelectric composite agarose hydrogel layer membrane distillation system is connected to the laundry wastewater pretreatment system, and the ultraviolet disinfection system is connected to the thermoelectric composite agarose hydrogel layer membrane distillation system for disinfecting distilled water.

[0012] As a preferred solution of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation described in the present invention, the rooftop photovoltaic system includes a photovoltaic fixed frame, a photovoltaic panel, an inverter, a battery, a cleaning nozzle, a water collection tank and a return pipe. The photovoltaic fixed frame is arranged on the roof of the building, the photovoltaic panel is arranged on the photovoltaic fixed frame, the battery is connected to the photovoltaic panel through an inverter, the cleaning nozzle is arranged on the top of the photovoltaic panel to clean the dust on the photovoltaic panel, the water collection tank is arranged at the bottom of the photovoltaic panel, and the water collection tank is connected to the laundry wastewater pretreatment system through a return pipe to collect and recycle the cleaned sewage.

[0013] As a preferred embodiment of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation of the present invention, the laundry wastewater pretreatment system includes a water supply pump, an activated carbon sedimentation filter device, and a pretreatment water storage tank. The activated carbon sedimentation filter device is connected to the drain pipe of the washing machine via the water supply pump to achieve sedimentation and adsorption of particulate matter in the wastewater. The pretreatment water storage tank is connected to the activated carbon sedimentation filter device to store the pretreated wastewater to be purified that does not contain solid particulate matter.

[0014] The activated carbon sedimentation and filtration device includes a three-way fork rod, a carbon storage tank, an ultrasonic cleaning and immersion tank and a driving motor. The three carbon storage tanks are arranged on the three-way fork rod and are used for filtering, cleaning, recycling and preparation. The carbon storage tank for filtering is connected to the bottom of the water pipe, and the sedimentation and adsorption of particulate matter in the sewage is achieved under the action of gravity; the ultrasonic cleaning and immersion tank is arranged at the carbon storage tank for cleaning and recycling, and the carbon storage tank for cleaning and recycling is placed in the ultrasonic cleaning and immersion tank. After a certain cleaning procedure, the activated carbon in the carbon storage tank restores its ability to filter particulate matter; the preparation carbon storage tank is arranged between the filtering carbon storage tank and the cleaning and recycling carbon storage tank, and contains activated carbon particles that have been cleaned and have restored their filtering ability; the driving motor is arranged on the three-way fork rod to drive the three carbon storage tanks on the three-way fork rod to rotate.

[0015] As a preferred solution of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation described in the present invention, the solar CPC dual-path preheating system includes a heat collecting pipe, a CPC concentrating and reflecting device, a heat transfer medium storage tank, a variable distribution pipe and a dual-path heat exchanger. The CPC concentrating and reflecting device is arranged on both sides of the heat collecting pipe for converging sunlight to increase the temperature of the heat transfer medium. The heat transfer medium storage tank is connected to one end of the heat collecting pipe, and the dual-path heat exchanger is connected to the other end of the heat collecting pipe through a variable distribution pipe so as to control the temperature of the wastewater to be membrane distilled after pre-treatment through the variable distribution pipe.

[0016] As a preferred embodiment of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation described in the present invention, the thermoelectric composite agarose hydrogel layer membrane distillation system includes a water supply pipe, a water supply pump, an insulating membrane distillation box, a thermoelectric device and a temperature control device. The insulating membrane distillation box is connected to the two-way heat exchanger through a water supply pipe. The water supply pump is arranged on the connecting pipe between the two-way heat exchanger and the pretreatment water storage tank to facilitate the drainage of the preheated sewage into the membrane distillation box, insulate the distillation box, maintain the operating temperature of the membrane distillation, and improve the efficiency of the membrane distillation. A polyester non-woven fabric support is provided in the thermal insulation membrane distillation box, and a distillation membrane is provided on the polyester non-woven fabric support for purifying sewage. An agarose hydrogel layer is provided on the distillation membrane for blocking the surfactants unique to laundry wastewater. The thermoelectric device is arranged between the thermal insulation membrane distillation box and the two-way heat exchanger. The temperature control device is arranged on the thermal insulation membrane distillation box for controlling the temperature of the water to be distilled.

[0017] As a preferred solution of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation described in the present invention, the ultraviolet disinfection system includes a disinfection pool and an ultraviolet irradiation lamp, the disinfection pool is connected to the thermal insulation membrane distillation box, and the ultraviolet irradiation lamp is arranged in the disinfection pool to thoroughly disinfect the distilled water for laundry or other uses.

[0018] As a preferred solution of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation described in the present invention, the solar CPC dual-path preheating system also includes a distribution baffle, a fixed shaft and a micro motor. The distribution baffle is arranged at the tail of the heat collecting tube through the fixed shaft to change the flow rate of the two paths of the variable distribution tube. The micro motor is arranged at the back of the heat collecting tube to drive the fixed shaft.

[0019] As a preferred solution of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation described in the present invention, a thermoelectric heating port is provided on the side where the thermal insulation membrane distillation box is connected to the thermoelectric device, so that the heat emitted by the thermoelectric device enters the thermal insulation membrane distillation box through the thermoelectric heating port.

[0020] The beneficial effects of the present invention are: through the mutual cooperation between the rooftop photovoltaic system, the laundry wastewater pretreatment system, the solar CPC dual-path preheating system, the thermoelectric composite agarose hydrogel layer membrane distillation system and the ultraviolet disinfection system, the campus laundry wastewater is efficiently purified, so as to facilitate the recycling and reuse of the campus laundry wastewater and avoid the pollution of the campus laundry wastewater to the river. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0022] Figure 1 Schematic diagram of the overall structure of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation.

[0023] Figure 2 Schematic diagram of the structure of the rooftop photovoltaic system of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation.

[0024] Figure 3 This is a schematic diagram of the structure of the laundry wastewater pretreatment system of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation.

[0025] Figure 4 This is a schematic diagram of the location and structure of the solar CPC dual-path preheating system, thermoelectric composite agarose hydrogel layer membrane distillation system and ultraviolet disinfection system of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation.

[0026] Figure 5 Schematic diagram of the structure of the thermoelectric device of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation in rainy day state.

[0027] Figure 6 Schematic diagram of the mechanism of the hydrogel layer's resistance to surfactant wetting.

[0028] Figure 7 Schematic diagram of the cleaning and recovery status of the carbon storage tank in the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation.

[0029] Figure 8 Schematic diagram of the internal structure of the dual-path heat exchanger of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation.

[0030] Figure 9 Schematic diagram of the structure of the thermoelectric device of the laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation.

[0031] In the figure: 1. Rooftop photovoltaic system; 11. Photovoltaic fixed frame; 111. Longitudinal bracket; 112. Horizontal connecting rod; 113. Frame frame; 114. Telescopic rod; 115. Fixed slot; 12. Photovoltaic panel; 13. Inverter; 14. Battery; 15. Cleaning nozzle; 16. Water collection tank; 17. Liquid return pipe; 2. Laundry wastewater pretreatment system; 21. Water pump; 22. Activated carbon sedimentation and filtration device; 221. Three-way fork rod; 222. Carbon storage tank; 223. Ultrasonic cleaning immersion tank; 224. Drive motor; 23. Pretreatment water storage tank; 3. Solar CPC dual-path preheating system; 31. Collecting tube; 32. CPC concentrating reflector; 33. Heat transfer medium storage tank; 34. Variable distribution pipe; 3 5. Dual-path heat exchanger; 351. Distillation box water inlet flow channel; 352. Upper heat transfer medium flow channel; 353. Lower heat transfer medium flow channel; 354. Cold source circulating water flow channel; 36. Distribution baffle; 37. Fixed shaft; 38. Micro motor; 4. Thermoelectric composite agarose hydrogel layer membrane distillation system; 41. Water supply pipe; 42. Water supply pump; 43. Insulated membrane distillation box; 431. Polyester non-woven fabric bracket; 432. Distillation membrane; 433. Agarose hydrogel layer; 44. Thermoelectric device; 441. Bracket; 442. Support plate; 443. Fixed frame; 444. Thermoelectric power generation sheet; 445. Wire; 45. Temperature control device; 46. Condensate storage tank; 5. Ultraviolet disinfection system; 51. Disinfection tank; 52. Ultraviolet irradiation lamp. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0034] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0035] Example

[0036] Reference Figures 1 to 9The present embodiment provides a laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation, which includes a rooftop photovoltaic system 1, a laundry wastewater pretreatment system 2, a solar CPC dual-path preheating system 3, a thermoelectric composite agarose hydrogel layer membrane distillation system 4 and an ultraviolet disinfection system 5. The rooftop photovoltaic system 1 is connected to the laundry wastewater pretreatment system 2 to generate electricity to supply the system. The solar CPC dual-path preheating system 3 is connected to the thermoelectric composite agarose hydrogel layer membrane distillation system 4 to adjust the temperature of the thermoelectric composite agarose hydrogel layer membrane distillation system 4. The thermoelectric composite agarose hydrogel layer membrane distillation system 4 is connected to the laundry wastewater pretreatment system 2. The ultraviolet disinfection system 5 is connected to the thermoelectric composite agarose hydrogel layer membrane distillation system 4 for disinfecting distilled water.

[0037] The laundry wastewater purification system is mainly composed of a rooftop photovoltaic system 1, a laundry wastewater pretreatment system 2, a solar CPC dual-path preheating system 3, a thermoelectric composite agarose hydrogel layer membrane distillation system 4 and an ultraviolet disinfection system 5. The rooftop photovoltaic system 1 is connected to the laundry wastewater pretreatment system 2. The rooftop photovoltaic system 1 generates electricity through solar power generation to provide electricity for the overall water purification system. The solar CPC dual-path preheating system 3 is connected to the thermoelectric composite agarose hydrogel layer membrane distillation system 4 to adjust the temperature of the thermoelectric composite agarose hydrogel layer membrane distillation system 4 and improve the efficiency of sewage purification. The thermoelectric composite agarose hydrogel layer membrane distillation system System 4 is connected to the laundry wastewater pretreatment system 2 to further purify the pre-treated sewage for the recycling of laundry wastewater. The ultraviolet disinfection system 5 is connected to the thermoelectric composite agarose hydrogel layer membrane distillation system 4 to thoroughly disinfect the distilled water for laundry or other uses. This sewage purification system is based on membrane distillation filtration to screen fresh water, and uses the agarose hydrogel layer 433 to block the unique surfactants in the laundry wastewater and protect the hydrophobic layer of the distillation membrane 432. Rooftop photovoltaic technology is used to provide the heat and electricity required by the system, reducing the footprint, responding to the advocacy of rooftop photovoltaics, and being green, sustainable, low-carbon and environmentally friendly, while saving water resources.

[0038] Specifically, the rooftop photovoltaic system 1 includes a photovoltaic fixed frame 11, a photovoltaic panel 12, an inverter 13, a battery 14, a cleaning nozzle 15, a water collection tank 16 and a return pipe 17. The photovoltaic fixed frame 11 is arranged on the roof of the building, the photovoltaic panel 12 is arranged on the photovoltaic fixed frame 11, the battery 14 is connected to the photovoltaic panel 12 through the inverter 13, the cleaning nozzle 15 is arranged at the top of the photovoltaic panel 12, the water collection tank 16 is arranged at the bottom of the photovoltaic panel 12, and the water collection tank 16 is connected to the laundry wastewater pretreatment system 2 through the return pipe 17.

[0039] The rooftop photovoltaic system 1 is mainly composed of a photovoltaic fixed frame 11, a photovoltaic panel 12, an inverter 13, a battery 14, a cleaning nozzle 15, a water collection tank 16 and a return pipe 17. The photovoltaic fixed frame 11 is fixedly installed on the roof of the building. It is mainly composed of a longitudinal bracket 111, a transverse connecting rod 112 and a frame frame 113. The longitudinal bracket 111 and the transverse connecting rod 112 constitute the support frame of the photovoltaic fixed frame 11. The frame frame 113 is installed on the support frame. The photovoltaic panel 12 is fixedly installed on the frame frame 113 so that the photovoltaic panel 12 is at a certain angle to the horizontal ground, so that the sunlight can better illuminate the photovoltaic panel 12 and make full use of the sunlight. A telescopic rod 114 is installed at the bottom end of the frame frame 113, and a fixed card slot 115 is installed at the top end. The longitudinal bracket 111 can be retracted so that the photovoltaic panel 12 can be displaced left and right along the bracket arrangement. There is a hook groove at the top of the photovoltaic panel 12, and multiple rows of matching grooves are provided at the corresponding positions of the frame frame 113, which can play a role of limiting and fixing, and is used to realize the angle adjustment of the photovoltaic panel 12, so as to adjust the horizontal angle according to the latitude and altitude of the roof photovoltaic system 1, thereby making full use of solar radiation. The battery 14 is connected to the photovoltaic panel 12 through the inverter 13, and the current generated by the photovoltaic panel 12 is converted into alternating current to supply the system operation or store it in the battery 14. A cleaning nozzle 15 is installed on the top of the photovoltaic panel 12, and a water collection tank 16 is installed at the bottom. The water collection tank 16 is connected to the laundry wastewater pretreatment system 2 through the return pipe 17. The cleaning nozzle 15 is used to regularly clean the dust or other dirt on the photovoltaic panel 12. The sewage after cleaning is guided by the water collection tank 16 to the return pipe 17, and can enter the laundry wastewater pretreatment system 2 for recycling and reuse.

[0040] The laundry wastewater pretreatment system 2 includes a water supply pump 21, an activated carbon sedimentation filter device 22 and a pretreatment water storage tank 23. The activated carbon sedimentation filter device 22 is connected to the drain pipe of the washing machine through the water supply pump 21, and the pretreatment water storage tank 23 is connected to the activated carbon sedimentation filter device 22;

[0041] Specifically, the activated carbon sedimentation and filtration device 22 includes a three-way fork rod 221, a carbon storage tank 222, an ultrasonic cleaning immersion tank 223 and a drive motor 224. The three carbon storage tanks 222 are arranged on the three-way fork rod 221 for filtering, cleaning, recovery and preparation. The ultrasonic cleaning immersion tank 223 is arranged at the carbon storage tank 222 for cleaning and recovery. The drive motor 224 is arranged on the three-way fork rod 221 to drive the three carbon storage tanks 222 on the three-way fork rod 221 to rotate.

[0042] The laundry wastewater pretreatment system 2 is mainly composed of a water supply pump 21, an activated carbon sedimentation filter device 22 and a pretreatment water storage tank 23, wherein the activated carbon sedimentation filter device 22 is composed of a three-way fork rod 221 that can rotate around an axis, a carbon storage tank 222, an ultrasonic cleaning immersion tank 223 and a rotating drive motor 224. The three-way fork rod 221 fixes three carbon storage tanks respectively to realize the integration of the three functional parts of filtration, cleaning recovery and preparation. The carbon storage tank 222 with filtering function is connected to the bottom of the water pipe, and realizes the sedimentation and adsorption of particulate matter in the sewage under the action of gravity. When the carbon storage tank 222 can no longer settle and adsorb particulate matter in the sewage after use, the rotating component on the three-way fork rod 221 is rotated to place it in the ultrasonic cleaning immersion tank 223. After a certain cleaning process, After the washing process, the activated carbon in the tank recovers its ability to filter particulate matter, thereby realizing the cleaning and recovery of the carbon storage tank 222. After completion, the cleaned carbon storage tank 222 is arranged between the carbon storage tank 222 with filtering function and the carbon storage tank 222 for cleaning and recovery. The activated carbon particles therein have been cleaned and their filtering ability has been restored. The driving motor 224 is installed on the three-way fork rod 221, driving the three-way fork rod 221 to rotate so that the three activated carbon tanks on the three-way fork rod 221 can rotate to realize the corresponding functions. The water pipe connected to the carbon storage tank 222 is connected to the drain pipe of the washing machine through the water supply pump 21 to facilitate the transportation of laundry wastewater into the water pipe. The outlet of the water pipe is connected to the pre-treatment water storage tank to store the pre-treated wastewater to be purified that does not contain solid particulate matter.

[0043] The solar CPC dual-path preheating system 3 includes a heat collecting pipe 31, a CPC concentrating and reflecting device 32, a heat transfer medium storage tank 33, a variable distribution pipe 34 and a dual-path heat exchanger 35. The CPC concentrating and reflecting device 32 is arranged on both sides of the heat collecting pipe 31, the heat transfer medium storage tank 33 is connected to one end of the heat collecting pipe 31, and the dual-path heat exchanger 35 is connected to the other end of the heat collecting pipe 31 through the variable distribution pipe 34.

[0044] The solar CPC dual-path preheating system 3 is mainly composed of a heat collecting pipe 31, a CPC concentrating and reflecting device 32, a heat transfer medium storage tank 33, a variable distribution pipe 34 and a dual-path heat exchanger 35. The CPC concentrating and reflecting device 32 is symmetrically installed on both sides of the heat collecting pipe 31 for converging sunlight to increase the temperature of the heat transfer medium. One end of the heat collecting pipe 31 is connected to the heat transfer medium storage tank 33 so that the heat transfer medium in the heat transfer medium storage tank 33 can smoothly enter the heat collecting pipe 31. The dual-path heat exchanger 35 is connected to the other end of the heat collecting pipe 31 through the variable distribution pipe 34. The function of the variable distribution pipe 34 is to control the temperature of the wastewater to be membrane distilled after pretreatment. Since the lower limit of the melting temperature of agarose hydrogel is 60°C, it needs to be subjected to certain temperature control. The implementation method is to install a thermistor in the membrane distillation device. Since the increase in the temperature of the thermistor will cause the resistance to decrease, the current load of the thermistor can be used. The water temperature is detected to further control the amount of heat transfer medium supplied. During the heat transfer process of the heat transfer medium on the other side, the higher its temperature is, the stronger its thermoelectric power generation capacity is. Therefore, there is no need to perform temperature control on it. The dual-path heat exchanger 35 is used for pre-treatment of wastewater and temperature difference power generation respectively. It should be noted that the dual-path heat exchanger 35 in this embodiment is composed of a distillation box water inlet channel 351, an upper heat transfer medium channel 352, a lower heat transfer medium channel 353, The thermoelectric device 44 and the cold source circulating water flow channel 354 are all fixed on the frame, among which the distillation box water inlet flow channel 351 is in close contact with the upper heat transfer medium flow channel 352, and a gap is established between the lower heat transfer medium flow channel 353 and the cold source circulating water flow channel 354, the size of which is to accommodate the height of the thermoelectric device 44, so that the three can be in close contact in sunny weather, and on rainy days, the thermoelectric device 44 is located in the thermoelectric heating port interlayer on the side of the insulation membrane distillation box 43.

[0045] The thermoelectric composite agarose hydrogel layer membrane distillation system 4 includes a water supply pipe 41, a water supply pump 42, an insulating membrane distillation box 43, a thermoelectric device 44 and a temperature control device 45. The insulating membrane distillation box 43 is connected to the two-way heat exchanger 35 through the water supply pipe 41. The water supply pump 42 is arranged on the connecting pipe between the two-way heat exchanger 35 and the pretreatment water storage tank 23. A polyester non-woven fabric bracket 431 is arranged in the insulating membrane distillation box 43, a distillation membrane 432 is arranged on the polyester non-woven fabric bracket 431, and an agarose hydrogel layer 433 is arranged on the distillation membrane 432. The thermoelectric device 44 is arranged between the insulating membrane distillation box 43 and the two-way heat exchanger 35, and the temperature control device 45 is arranged on the insulating membrane distillation box 43.

[0046] The thermoelectric composite agarose hydrogel layer membrane distillation system 4 is mainly composed of a water supply pipe 41, a water supply pump 42, an insulating membrane distillation box 43, a thermoelectric device 44 and a temperature control device 45. The water supply pump 42 is installed on the connecting pipe between the two-way heat exchanger 35 and the pretreatment water storage tank 23 to facilitate the transportation of preheated sewage into the insulating membrane distillation box 43. The insulating membrane distillation box 43 is insulated to maintain the operating temperature of the membrane distillation and improve the efficiency of the membrane distillation. At the same time, the surface of the insulating membrane distillation box 43 is covered with insulation material except for the two sides in contact with the thermoelectric device 44 to play a role in insulation. The thermoelectric device 44 is installed between the insulating membrane distillation box 43 and the two-way heat exchanger 35. A temperature control device 45 is installed on it to control the temperature of the water to be distilled. On the one hand, the increase in temperature can improve the efficiency of membrane distillation, but on the other hand, the agarose hydrogel layer 433 limits the temperature from rising indefinitely. Therefore, the temperature control device 45 is an exact guarantee for the effectiveness and efficiency of the system. The thermoelectric device 44 has two working modes. In sunny weather, it serves as a power generation module. The source of the temperature difference is the wastewater circulating in from the pre-treatment water storage tank 23 and the lower heat transfer medium. It generates electricity through the temperature difference; in rainy days, it serves as a heat source for membrane distillation preheating and a cold source for water vapor condensation after membrane distillation to ensure efficient and stable operation of the system. The temperature control device 45 is used to control the temperature of the water to be distilled. A polyester non-stick film is installed in the thermal insulation membrane distillation box 43. The textile support 431 and the polyester non-woven fabric support 431 are provided with a distillation membrane 432, and the distillation membrane 432 is provided with an agarose hydrogel layer 433, wherein the distillation membrane 432 adopts a polytetrafluoroethylene (PETT) membrane, which is used to purify sewage so that only water vapor molecules in the sewage can pass through, and thus has an extremely high purification rate, and the agarose hydrogel layer 433 is closely attached to the hydrophobic layer side of the distillation membrane 432, and is used to block the surfactants unique to laundry wastewater. It should be noted that a guide rail is provided between the dual-path heat exchanger 35 and the thermal insulation membrane distillation box 43 to facilitate the left and right movement of the thermoelectric device 44, so as to facilitate different working modes, and an exhaust fan is installed in the thermal insulation membrane distillation box 43, and the inside of the box The upper side in contact with the thermoelectric device 44 is in a connected state, and is also connected to the condensation water storage tank 46 through a pipeline. The exhaust fan is used to drain the water vapor on one side of the distillation membrane 432 into the condensation water storage tank 46. The thermoelectric device 44 is composed of a bracket 441, a support plate 442, a fixed frame 443, a thermoelectric power generation sheet 444 and a wire 445. The bracket 441 supports the support plate 442, and a guide rail is provided on the bracket 441. The support plate 442 can slide back and forth on the guide rail. The fixed frame 443 is installed on the support plate 442, and the thermoelectric power generation sheet 444 is installed on the fixed frame 443, so that the thermoelectric device 44 generates electricity. The wire 445 is installed on the thermoelectric power generation sheet 444 to facilitate the transmission of the generated electricity.

[0047] The ultraviolet disinfection system 5 includes a disinfection pool 51 and an ultraviolet irradiation lamp 52 . The disinfection pool 51 is connected to the thermal insulation membrane distillation tank 43 , and the ultraviolet irradiation lamp 52 is arranged in the disinfection pool 51 .

[0048] The ultraviolet disinfection system 5 is mainly composed of a disinfection tank 51 and an ultraviolet irradiation lamp 52. The disinfection tank 51 is installed on one side of the thermal insulation membrane distillation box 43, and the disinfection tank 51 is connected to the condensation water storage tank 46, so that the distilled water in the condensation water storage tank 46 can enter the disinfection tank 51. An ultraviolet irradiation lamp 52 is installed in the disinfection tank 51 to thoroughly disinfect the distilled water and directly lead it out from the faucet for washing or other uses.

[0049] Furthermore, the solar CPC dual-path preheating system 3 also includes a distribution baffle 36 , a fixed shaft 37 and a micro motor 38 . The distribution baffle 36 is arranged at the tail of the heat collecting tube 31 through the fixed shaft 37 , and the micro motor 38 is arranged at the back of the heat collecting tube 31 .

[0050] A distribution baffle 36 is installed at the focus of the CPC concentrator at the center of the diameter of the heat collecting tube 31 and at the tail of the heat collecting tube 31 through a fixed shaft 37. The distribution baffle 36 can rotate around the axial direction of the fixed shaft 37. A micro motor 38 is installed on the back of the heat collecting tube 31, and the middle is insulated by insulation material to protect the safe operation of the motor. The driving shaft of the micro motor 38 is connected to the fixed shaft 37. The micro motor 38 is controlled by the current signal of the thermistor. When the micro motor 38 is started, it drives the fixed shaft 37 to rotate, and the fixed shaft 37 drives the distribution baffle 36 to rotate, thereby changing the flow rate of the two paths of the variable distribution tube 34.

[0051] A thermoelectric heating port is installed on one side of the thermal insulation membrane distillation box 43 connected to the thermoelectric device 44 so that the heat emitted by the thermoelectric device 44 can enter the thermal insulation membrane distillation box 43 through the thermoelectric heating port.

[0052] During use, under sunny working conditions, the laundry wastewater is collected by the water supply pump 21 and concentrated into the pre-treatment water storage tank 23 through the activated carbon sedimentation filter device 22. This step can effectively filter the sediment in the water. Then, the wastewater in the pre-treatment water storage tank 23 is pumped by the water supply pump 42 to the top channel of the dual-path heat exchanger 35, and after sufficient heat exchange, it enters the bottom layer of the thermal insulation membrane distillation box 43 for membrane distillation water purification; the water vapor on the upper layer of the thermal insulation membrane distillation box 43 enters the air outlet on the upper side under the drainage action of the fan and enters the condensation water storage tank 46, and then enters the disinfection tank 51 from the condensation water storage tank 46, and can be recycled after disinfection; in this process, the CPC type focusing reflection device 32 can reflect The large amount of sunlight collected by the heat collecting tubes 31 rapidly heats up. Under the combined control of the temperature control device 45 and the variable distribution pipe 34 inside the thermal membrane distillation box 43, when the water temperature at the bottom layer of the thermal membrane distillation box 43 exceeds 60°C, the distribution baffle 36 is controlled to the right, reducing the amount of heat transfer medium entering the upper heat exchange channel, thereby lowering the distillation box temperature. When the water temperature is below 60°C, the distribution baffle 36 is controlled to the left, increasing the amount of heat transfer medium entering the upper heat exchanger, thereby raising the distillation box temperature and maintaining the efficient and stable operation of the thermal membrane distillation box 43. At this time, the thermoelectric device 44 is located in the interlayer between the lower heat exchange channel and the condensed water circulation channel of the dual-path heat exchanger 35, and its function is to generate electricity.

[0053] Under rainy conditions, laundry wastewater is collected by the water supply pump 21 and concentrated into the pre-treatment water storage tank 23 through the activated carbon sedimentation filter device 22. This step can effectively filter the sediment in the water. Then, the wastewater in the pre-treatment water storage tank 23 is pumped by the water supply pump 42 to the top channel of the dual-path heat exchanger 35, and then directly enters the bottom layer of the thermal insulation membrane distillation box 43. At this time, the thermoelectric device 44 consumes electricity and is located inside the thermoelectric heating port of the thermal insulation membrane distillation box 43, with the cooling end facing up and the heating end facing down; the cooling energy generated by the cooling end is used to condense the water vapor on the upper layer of the thermal insulation membrane distillation box 43, and the heat generated by the heating end is used to preheat the wastewater to be distilled at the bottom layer of the thermal insulation membrane distillation box 43; it also flows into the condensation water storage tank 46, and then flows into the disinfection tank 51 from the condensation water storage tank 46, and is disinfected by the ultraviolet lamp 52 and then flows out directly through the faucet for use.

[0054] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation, characterized by: The invention comprises a rooftop photovoltaic system (1), a laundry wastewater pretreatment system (2), a solar CPC-type dual-path preheating system (3), a thermoelectric composite agarose hydrogel layer membrane distillation system (4) and an ultraviolet disinfection system (5), wherein the rooftop photovoltaic system (1) is connected to the laundry wastewater pretreatment system (2) to generate an electricity supply system, the solar CPC-type dual-path preheating system (3) is connected to the thermoelectric composite agarose hydrogel layer membrane distillation system (4) to adjust the temperature of the thermoelectric composite agarose hydrogel layer membrane distillation system, the thermoelectric composite agarose hydrogel layer membrane distillation system (4) is connected to the laundry wastewater pretreatment system (2), and the ultraviolet disinfection system (5) is connected to the thermoelectric composite agarose hydrogel layer membrane distillation system (4) for disinfecting distilled water; The solar CPC dual-path preheating system (3) comprises a heat collecting pipe (31), a CPC concentrating reflector (32), a heat transfer medium storage tank (33), a variable distribution pipe (34) and a dual-path heat exchanger (35), wherein the CPC concentrating reflector (32) is arranged on both sides of the heat collecting pipe (31), the heat transfer medium storage tank (33) is connected to one end of the heat collecting pipe (31), and the dual-path heat exchanger (35) is connected to the other end of the heat collecting pipe (31) via the variable distribution pipe (34); The thermoelectric composite agarose hydrogel layer membrane distillation system (4) includes a water supply pipe (41), a water supply pump (42), a thermal insulation membrane distillation box (43), a thermoelectric device (44) and a temperature control device (45). The thermal insulation membrane distillation box (43) is connected to the two-way heat exchanger (35) through the water supply pipe (41). The water supply pump (42) is arranged on the connecting pipe between the two-way heat exchanger (35) and the pretreatment water storage tank (23). A polyester non-woven fabric support (431) is provided in the box (43), a distillation membrane (432) is provided on the polyester non-woven fabric support (431), an agarose hydrogel layer (433) is provided on the distillation membrane (432), the thermoelectric device (44) is provided between the thermal insulation membrane distillation box (43) and the double-path heat exchanger (35), and the temperature control device (45) is provided on the thermal insulation membrane distillation box (43) for controlling the temperature of the water to be distilled.

2. The laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation according to claim 1, characterized in that: The rooftop photovoltaic system (1) comprises a photovoltaic fixing frame (11), a photovoltaic panel (12), an inverter (13), a battery (14), a cleaning nozzle (15), a water collecting tank (16) and a liquid return pipe (17). The photovoltaic fixing frame (11) is arranged on the roof of a building, the photovoltaic panel (12) is arranged on the photovoltaic fixing frame (11), the battery (14) is connected to the photovoltaic panel (12) via the inverter (13), the cleaning nozzle (15) is arranged on the top of the photovoltaic panel (12), the water collecting tank (16) is arranged on the bottom of the photovoltaic panel (12), and the water collecting tank (16) is connected to the laundry wastewater pretreatment system (2) via the liquid return pipe (17).

3. The laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation according to claim 1, characterized in that: The laundry wastewater pretreatment system (2) comprises a water supply pump (21), an activated carbon sedimentation filter device (22) and a pretreatment water storage tank (23), wherein the activated carbon sedimentation filter device (22) is connected to the drain pipe of the washing machine via the water supply pump (21), and the pretreatment water storage tank (23) is connected to the activated carbon sedimentation filter device (22); The activated carbon sedimentation and filtration device (22) comprises a three-way fork rod (221), a carbon storage tank (222), an ultrasonic cleaning and soaking tank (223), and a driving motor (224). The three carbon storage tanks (222) are arranged on the three-way fork rod (221) for filtering, cleaning, recycling, and preparation. The ultrasonic cleaning and soaking tank (223) is arranged at the carbon storage tank (222) for cleaning and recycling. The driving motor (224) is arranged on the three-way fork rod (221) for driving the three carbon storage tanks on the three-way fork rod to rotate.

4. The laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation according to claim 1, characterized in that: The ultraviolet disinfection system (5) comprises a disinfection pool (51) and an ultraviolet irradiation lamp (52). The disinfection pool (51) is connected to the thermal insulation membrane distillation box (43), and the ultraviolet irradiation lamp (52) is arranged in the disinfection pool (51).

5. The laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation according to claim 1, characterized in that: The solar CPC dual-path preheating system (3) further comprises a distribution baffle (36), a fixed shaft (37) and a micro motor (38), wherein the distribution baffle (36) is arranged at the tail of the heat collecting tube (31) via the fixed shaft (37), and the micro motor (38) is arranged at the back of the heat collecting tube (31).

6. The laundry wastewater purification system based on composite agarose hydrogel layer membrane distillation according to claim 1, characterized in that: A thermoelectric heating port is provided on one side of the thermal insulation membrane distillation box (43) connected to the thermoelectric device (44).

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