A coupling method for cleaning waste plastics and recycling humus soil by using landfill leachate

Abstract

The application provides a coupling method for cleaning waste plastics by using landfill leachate and recycling humus, and relates to the technical field of garbage treatment.The coupling method comprises the following steps: using deodorized landfill leachate to clean the mud attached to the waste plastics, performing solid-liquid separation on the slurry after mud removal, returning the obtained liquid phase to the deodorization for recycling, reducing water resource consumption, recycling the obtained solid phase as humus, and adsorbing the difficult-to-degrade humic acid separated from the solid phase in the landfill leachate into the recycled humus.The coupling method not only realizes the reduction and recycling of the landfill leachate, improves the added value of the waste plastics, but also fully utilizes the system characteristics of the landfill site, and solves the problem of landfill leachate treatment of the garbage pile.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste treatment, in particular to a coupling method for cleaning waste plastics and recycling humus soil by using landfill leachate. BACKGROUND

[0002] At present, landfill leachate refers to the water contained in the garbage itself, the rain and snow water entering the landfill site, and the water produced by the degradation of biomass, deducting the saturated water holding capacity of the garbage and the soil layer, and forming a kind of high-concentration organic wastewater after passing through the garbage layer and the soil layer. It contains a large amount of refractory substances, suspended solids, ammonia nitrogen, mercaptans and other pollutants. At present, it is mainly treated by high-level oxidation method and permeable membrane method, and the investment in treatment facilities and equipment is huge, and the treatment cost is as high as hundreds of yuan, which becomes the main burden of landfill pollution control. There are also cases of joint treatment with municipal sewage treatment plants, but due to the influence of transportation cost and short-time impact load of sewage treatment, it is easy to cause abnormal fluctuation of sewage treatment system effluent or even cannot meet the discharge standard, therefore, many sewage treatment plants are reluctant to accept landfill leachate. For landfill sites with saturated or saturated capacity, due to the continuous fermentation and degradation of the filled garbage, landfill leachate will continue to be produced in the future for decades, causing the continuous increase of landfill operation and maintenance cost. How to reduce the production of landfill leachate and reduce the treatment cost is the key problem of reducing the operation cost of landfill.

[0003] However, according to the water and gas migration characteristics of the landfill site, the garbage often appears in the dry and wet alternating area in the process of biological degradation and mineralization, and many factors such as garbage composition, stacking method, covering material and methane drainage will cause great difference in water holding capacity of different areas of the stack. How to fully utilize the water holding capacity of unsaturated mineralized garbage, play the adsorption role of mineralized garbage, reduce the production of leachate, and repeatedly use more than 99% of the water contained in the landfill leachate to wash off the silt adhered to the waste plastics in the landfill site, so as to realize the system circulation of leachate and further reduce the production of leachate, which will reduce the treatment cost and produce more economic benefits. SUMMARY

[0004] In view of the problems in the prior art, the application provides a coupling method for cleaning waste plastics by using landfill leachate and recycling humus soil, which comprises the following steps: using deodorized landfill leachate to clean the mud attached to the waste plastics, performing solid-liquid separation on the mud-removed slurry, recycling the obtained liquid phase to the deodorization, reducing water resource consumption, and recycling the obtained solid phase as humus soil, wherein the recycled humus soil adsorbs humic acid separated from the landfill leachate and converted into solid phase; the coupling method not only realizes the reduction and recycling of the landfill leachate and improves the added value of the waste plastics, but also fully utilizes the system characteristics of the landfill site and solves the problem of landfill leachate treatment of the landfill body.

[0005] To achieve the above object, the application adopts the following technical scheme:

[0006] The application aims to provide a coupling method for cleaning waste plastics by using landfill leachate and recycling humus soil, which comprises the following steps:

[0007] Deodorizing the landfill leachate to obtain deodorized landfill leachate; removing the mud from the waste plastics by using the deodorized landfill leachate to obtain mud-removed plastics and mud-removed slurry; performing solid-liquid separation on the mud-removed slurry, recycling the obtained liquid phase to the deodorization, and recycling the obtained solid phase as humus soil.

[0008] As a preferred technical scheme of the application, the deodorization comprises any one or a combination of at least two of biochemical treatment, strong oxidation treatment or mineralized landfill adsorption treatment.

[0009] As a preferred technical scheme of the application, the odor concentration of the deodorized landfill leachate is less than 10.

[0010] As a preferred technical scheme of the application, the waste plastics are crushed before the mud removal, and the crushed particle size is less than 10 cm.

[0011] As a preferred technical scheme of the application, the mud removal is performed by using a spiral mud remover, and the rotation speed is controlled to be 300-700 rpm.

[0012] As a preferred technical scheme of the application, in the mud removal, the mass ratio of the deodorized landfill leachate to the waste plastics is (1-10):1.

[0013] As a preferred technical scheme of the application, the mud-removed plastics are sequentially subjected to dewatering and drying to obtain clean dry plastics.

[0014] As a preferred technical scheme of the application, the dewatering is performed by using a high-speed dewatering machine, and the rotation speed is controlled to be 2500-3000 rpm.

[0015] As a preferred technical scheme of the present application, the moisture content of the dehydrated plastic is 4-10 wt%.

[0016] As a preferred technical scheme of the present application, the solid-liquid separation comprises sequentially performed standing sedimentation and dehydration, and the recovered water obtained by the standing sedimentation and the dehydration is returned to the deodorization for recycling.

[0017] As a preferred technical scheme of the present application, the moisture content of the humus is 10-70 wt%.

[0018] As a preferred technical scheme of the present application, the coupling method comprises the following steps:

[0019] (1) The landfill leachate is deodorized to obtain deodorized landfill leachate; the deodorization comprises any one or a combination of at least two of the following: aeration of the landfill leachate into an aerobic sludge treatment tank, strong oxidant oxidation or mineralized waste adsorption in an adsorption tower, that is, the deodorization comprises any one or a combination of at least two of biochemical treatment, strong oxidation treatment or mineralized waste adsorption treatment, and the odor concentration of the deodorized landfill leachate is below 10;

[0020] (2) The waste plastic sorted out by excavation and screening of the landfill is crushed, the particle size of the crushed waste plastic is below 10 cm, then the crushed waste plastic is mixed with the deodorized landfill leachate in a spiral desliming machine for desliming, the rotation speed of the spiral desliming machine is controlled to be 300-700 rpm, and the mass ratio of the deodorized landfill leachate to the waste plastic is controlled to be (1-10):1, more than 80% of the mud and sand adhered to the surface of the waste plastic can be cleaned and removed, and de-slimed plastic and de-slimed slurry are obtained;

[0021] The de-slimed plastic enters a high-speed dehydrator for dehydration, the rotation speed of the high-speed dehydrator is controlled to be 2500-3000 rpm, the moisture content of the dehydrated plastic is 4-10 wt%, and finally clean dry plastic is obtained by drying;

[0022] (3) The de-slimed slurry is guided to a sedimentation tank for standing sedimentation, the settled mud is dehydrated in a dehydrator, and the obtained solid phase is recovered as humus, the humus continuously accumulates humic substances and other components in the landfill leachate, the moisture content of the humus is 10-70 wt%, and the supernatant of the standing sedimentation and the liquid phase water obtained by dehydration are respectively recycled to the deodorization step, and then enter the spiral desliming machine again for desliming of the crushed waste plastic.

[0023] Compared with the prior art, the present application has at least the following beneficial effects:

[0024] The coupling method of the application is that landfill leachate is subjected to oxygenation and volatile odor removal, then enters the waste plastic washing device to wash off the mud adhered to the waste plastic, the washing liquid is subjected to sedimentation and then separated into solid humus and liquid water by the dewatering device, the liquid water is recycled into the waste plastic washing device to reduce water resource consumption, and the solid humus adsorbs the refractory humus in the leachate. The application not only realizes the reduction and recycling of the leachate and improves the added value of the waste plastic, but also solves the problem of leachate treatment of the garbage heap by fully utilizing the characteristics of the landfill system. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a flowchart of the coupling method of the application for washing waste plastic with landfill leachate and recycling humus in a specific embodiment. DETAILED DESCRIPTION

[0026] The application provides a coupling method for washing waste plastic with landfill leachate and recycling humus, which comprises the following steps:

[0027] The landfill leachate is subjected to deodorization to obtain deodorized landfill leachate; the deodorized landfill leachate is used to wash off the mud adhered to the waste plastic to obtain washed plastic and washed slurry; the washed slurry is subjected to solid-liquid separation, the obtained liquid phase is recycled to the deodorization, and the obtained solid phase is recycled as humus.

[0028] In the coupling method, the deodorized landfill leachate is used to wash off the mud adhered to the waste plastic, the washed slurry is subjected to solid-liquid separation, the obtained liquid phase is recycled to the deodorization to reduce water resource consumption, the obtained solid phase is recycled as humus, the humus adsorbs the humic acid in the landfill leachate which is converted into solid phase and separated out, the coupling method not only realizes the reduction and recycling of the landfill leachate and improves the added value of the waste plastic, but also solves the problem of landfill leachate treatment of the garbage heap by fully utilizing the characteristics of the landfill system.

[0029] Both landfill leachate and waste plastics screened from landfills are odorous pollutants. To meet odor emission standards, those skilled in the art often treat them separately. Directly treating landfill leachate to render it harmless typically requires a complex combination of processes: pretreatment, biochemical treatment, and advanced treatment. However, the content of harmful substances such as organic pollutants, ammonia nitrogen, heavy metals, and salts in landfill leachate fluctuates significantly, making it difficult to guarantee the effectiveness of the aforementioned complex process. Furthermore, with the accumulation of rainwater, snowmelt, and water from biomass degradation in landfills, the production of landfill leachate fluctuates greatly, and the total production is increasing, making the harmless treatment of landfill leachate technically very challenging. Directly treating waste plastics to render them harmless often requires the initial washing with tap water or reclaimed water, which not only consumes large amounts of tap water or reclaimed water but also requires additional treatment of the large amount of wash water generated during washing.

[0030] In this regard, the present invention overcomes the technical biases of those skilled in the art. After deodorizing the landfill leachate, especially when the odor concentration of the deodorized leachate is below 10 and the solid content is low with a water content still above 95%, even above 99%, it can be used to wash the mud attached to waste plastics, thereby obtaining economically viable humus. This achieves the coupled treatment of two odorous pollutants, significantly reducing treatment costs. The recovered humus mainly consists of the mud attached to the waste plastics, with the remainder being insoluble solid phases and precipitated solid phases from the landfill leachate. The deodorized landfill leachate is used to desludge the waste plastics. Soluble components such as heavy metals, salts, and humic acids in the landfill leachate mainly enter the circulating liquid phase. Only after reaching a certain saturation level or under alkaline conditions will they precipitate into solid phases and enter the humus. Therefore, compared to landfill leachate, humus recovered as solid waste has two advantages: firstly, the yield is significantly reduced, and the costs of storage and transportation are correspondingly lower; secondly, only a small portion of the soluble harmful substances such as heavy metals and salts from landfill leachate are converted into solid phases and precipitated into the humus. Sometimes, the recovered humus fully meets the environmental protection requirements for direct application. Even if the content of harmful substances such as heavy metals and salts in the humus exceeds the standard, the technical difficulty of treatment is relatively low, and it still has economic value for sale on the market. For example, due to the attenuation effect, dominant channel effect, and re-adsorption chelation effect of heavy metal distribution, heavy metals in humus will be enriched in some areas. By screening with technologies such as hyperspectral detection, the yield of humus requiring heavy metal harmless treatment will be further reduced. Therefore, the humus recovered using this application has excellent economic value.

[0031] Preferably, the deodorization includes any one or a combination of at least two of the following: biochemical treatment, strong oxidation treatment, or mineralized waste adsorption treatment.

[0032] Preferably, the odor concentration of the deodorized landfill leachate is less than 10.

[0033] It should be noted that the value of the odor concentration is equal to the dilution multiple of the sample diluted with odorless air until the odor cannot be identified by the odor identification personnel, which is dimensionless. The coupling method of the present application strictly controls the odor concentration of the deodorized landfill leachate to be less than 10, which meets the emission standard of malodorous pollutants, and can achieve the cleaning effect of waste plastics and ensure the product quality of the subsequent humus soil.

[0034] Preferably, the waste plastics are crushed before the desliming, and the crushed particle size is less than 10 cm.

[0035] Preferably, the desliming is performed by a spiral desliming machine, and the rotation speed is controlled to be 300-700 revolutions per minute, such as 300 revolutions per minute, 350 revolutions per minute, 400 revolutions per minute, 450 revolutions per minute, 500 revolutions per minute, 550 revolutions per minute, 600 revolutions per minute, 650 revolutions per minute, or 700 revolutions per minute, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0036] As a preferred technical solution of the present application, in the desliming, the mass ratio of the deodorized landfill leachate to the waste plastics is (1-10):1, such as 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0037] It should be noted that the coupling method of the present application controls the mass ratio of the deodorized landfill leachate to the waste plastics to be (1-10):1. If the amount of the deodorized landfill leachate is too small, the cleaning effect of the waste plastics cannot be guaranteed. If the amount of the deodorized landfill leachate is too large, the solid content of the slurry after desliming is low, which is not conducive to obtaining humus soil with a suitable moisture content, the equipment investment for solid-liquid separation is increased, the solid-liquid separation effect is not good, and the energy consumption is increased.

[0038] As a preferred technical solution of the present application, the dehydrated plastics are sequentially dehydrated and dried to obtain clean dry plastics.

[0039] As a preferred technical solution of the present application, the dehydration is performed by a high-speed dehydrator, and the rotation speed is controlled to be 2500-3000 revolutions per minute, such as 2500 revolutions per minute, 2600 revolutions per minute, 2700 revolutions per minute, 2800 revolutions per minute, 2900 revolutions per minute, or 3000 revolutions per minute, etc., but not limited to the listed values, and other values not listed in the above value range are also applicable.

[0040] As a preferred technical solution of the present application, the moisture content of the dehydrated plastic is 4-10wt%, for example, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt% or 10wt%, etc., but not limited to the listed values, other values not listed within the above numerical range are also applicable.

[0041] As a preferred technical solution of the present application, the solid-liquid separation includes static sedimentation and dehydration performed in sequence, and the recovered water obtained by the static sedimentation and the dehydration is returned to the deodorization for recycling.

[0042] As a preferred technical solution of the present application, the moisture content of the humus soil is 10-70wt%, for example, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, 65wt% or 70wt%, etc., but not limited to the listed values, other values not listed within the above numerical range are also applicable.

[0043] It should be noted that the moisture content of the humus soil can be adjusted according to different needs of customers in the market, for example, the moisture content of the humus soil used for saline-alkali land reclamation is generally 50-70wt%, and the moisture content of the humus soil used for seedling cultivation and other planting industries is generally 10-30wt%.

[0044] As a preferred technical solution of the present application, the coupling method comprises the following steps:

[0045] (1) The landfill leachate is deodorized to obtain deodorized landfill leachate; the deodorization includes: any one or a combination of at least two of the following: directing the landfill leachate into an aerobic sludge treatment tank for aeration, oxidizing with a strong oxidizing agent, or adsorbing in a mineralized waste adsorption tower, that is, any one or a combination of at least two of the following: biochemical treatment, strong oxidation treatment, or mineralized waste adsorption treatment, and the odor concentration of the deodorized landfill leachate is below 10;

[0046] (2) The waste plastic sorted out by excavating and screening the landfill site is crushed, the particle size of the crushed waste plastic is below 10cm, then the crushed waste plastic is mixed with the deodorized landfill leachate in a spiral desliming machine for desliming, the rotation speed of the spiral desliming machine is controlled to be 300-700r / min, and the mass ratio of the deodorized landfill leachate to the waste plastic is controlled to be (1-10):1, more than 80% of the mud and sand adhered to the surface of the waste plastic can be cleaned and removed, and de-sludged plastic and de-sludged slurry are obtained;

[0047] The plastic after desliming is subjected to dewatering in a high-speed dewatering machine, the rotating speed of the high-speed dewatering machine is controlled to be 2500-3000 rpm, and the moisture content of the plastic after dewatering is 4-10 wt%, and finally, the clean dry plastic is obtained through drying.

[0048] (3) The slurry after desliming is guided to a sedimentation tank for static sedimentation, the sediment is subjected to dewatering in a dewatering machine, and the solid phase is recycled as humus soil, the humus soil is continuously accumulated with components such as humus in the landfill leachate, and the water content of the humus soil is 10-70 wt%, and the supernatant after static sedimentation and the liquid phase after dewatering are respectively recycled to the deodorization step, and then subjected to deodorization and then enter the spiral deslimer again to deslime the crushed waste plastic.

[0049] It should be noted that the dewatering machine can be reasonably selected according to the actual situation, for example, a centrifugal dewatering machine, a stacked spiral sludge dewatering machine, etc. can be selected, and the solid phase obtained by dewatering can also be selected according to the actual situation whether to be dried to control the target water content of the recycled humus soil.

[0050] It should be noted that the spiral deslimer of the present application can remove more than 90% of the soil on the waste plastic, and the calorific value of the waste plastic is increased by more than 5 times; the cutterhead of the crusher for crushing the waste plastic is 3-5 cm in diameter and made of wear-resistant alloy, and the crushing particle size is less than 10 cm; the sedimentation tank for static sedimentation can be a vertical flow type sedimentation tank or an inclined plate sedimentation tank; the coupling method of the present application does not use clean rainwater, groundwater, river water and other water resources, and the humic acid in the landfill leachate is separated into the solid phase humus soil, and the ammonia nitrogen in the landfill leachate is reduced to less than 25 mg after oxidation and circulation.

[0051] The technical solutions of the present application will be further described below in conjunction with the drawings and through specific embodiments.

[0052] One specific embodiment of the present application provides a coupling method for cleaning waste plastic with landfill leachate and recycling humus soil, and a flowchart thereof is shown in Figure 1 The coupling method comprises the following steps:

[0053] (1) The landfill leachate is deodorized to obtain deodorized landfill leachate; the deodorization includes any one or a combination of at least two of the following: aeration in an aerobic sludge treatment tank, strong oxidant oxidation or mineralized landfill adsorption, that is, the deodorization includes any one or a combination of at least two of the following: biochemical treatment, strong oxidation treatment or mineralized landfill adsorption treatment, and the odor concentration of the deodorized landfill leachate is less than 10;

[0054] (2) crushing the waste plastics separated by excavating, screening and sorting in the landfill, the particle size of the crushed waste plastics is below 10 cm, then the crushed waste plastics enter the spiral desliming machine and mix with the deodorized landfill leachate for desliming, the rotating speed of the spiral desliming machine is controlled to be 300-700 revolutions per minute, and the mass ratio of the deodorized landfill leachate to the waste plastics is (1-10):1, more than 80% of the mud and sand adhered to the surface of the waste plastics can be cleaned and removed, and the deslimed plastics and deslimed slurry are obtained;

[0055] The deslimed plastics enter the high-speed dewatering machine for dewatering, the rotating speed of the high-speed dewatering machine is controlled to be 2500-3000 revolutions per minute, and the moisture content of the dewatered plastics is 4-10 wt%, and finally the clean dry plastics are obtained by drying;

[0056] (3) the deslimed slurry is guided to the sedimentation tank for standing and sedimentation, the sediment enters the dewatering machine for dewatering, the obtained solid phase is recycled as humus soil, the humus soil continuously accumulates humic substances and other components in the landfill leachate, the water content of the humus soil is 10-70 wt%, and the supernatant of the standing and sedimentation and the liquid phase water obtained by dewatering are respectively recycled as circulating water to the deodorization step, and then enter the spiral desliming machine again to deslime the crushed waste plastics.

[0057] In order to better illustrate the present application and facilitate understanding of the technical solutions of the present application, the typical but non-limiting embodiments of the present application are as follows:

[0058] Embodiment 1

[0059] There are about 30,000 tons of landfill leachate in the landfill area of a county, and the detection shows that the suspended solids SS in the landfill leachate is 3000-6000 ppm, the heavy metal content does not exceed the standard, meets the requirements of GB 16889-2024, the conductivity is 16000-17000 μS / cm, and according to the current market processing cost, about 3-5 million yuan is needed to process the standard discharge.

[0060] The existing landfill has 500,000 tons of garbage, and 100,000 tons of waste plastics can be separated by excavation and screening, but due to the high content of mud and sand on the waste plastics, the content of mud and sand on the waste plastics is about 40-60 wt%, and the heat value is low, if sent to the garbage incinerator for incineration, about 6-10 million yuan needs to be invested.

[0061] The garbage is screened and separated after excavation, and the separated plastic is crushed. The particle size of the crushed plastic is below 10 cm, and the plastic enters the spiral de-sliming machine through the belt. At the same time, the garbage leachate is guided into the aerobic sludge oxidation tank, and aeration is carried out in the oxidation tank for 20 hours, so that the odor concentration of the deodorized garbage leachate is below 10. The deodorized garbage leachate is also pumped into the spiral de-sliming machine. After detection, the suspended solids (SS) in the deodorized garbage leachate are reduced to 2000 ppm to 3000 ppm, the heavy metal content does not exceed the standard, meets the requirements of GB 16889-2024, and the conductivity is reduced to 12000 to 15000 μS / cm. The rotation speed of the spiral de-sliming machine is controlled to be 500 to 1000 revolutions per minute, and the mass ratio of the deodorized garbage leachate to the waste plastic is (1 to 5):1. More than 80% of the mud and sand adhered to the surface of the waste plastic can be cleaned and removed, and the de-slimed plastic and the de-slimed slurry are obtained. After the spiral de-sliming machine treatment, the de-slimed waste plastic enters the high-speed dehydrator, and the rotation speed of the high-speed dehydrator is controlled to be 1500 to 2500 revolutions per minute, so that the mud content on the surface is reduced to below 10%, and the water content is reduced to about 6%. The calorific value of the waste plastic is increased from 1000 large calories to 6000 large calories. The de-slimed slurry discharged from the spiral de-sliming machine enters the sedimentation tank for static sedimentation, and the settled mud after static sedimentation is dehydrated by the dehydrator to obtain about 40,000 tons of humus soil with a water content of about 60wt%. After detection, the heavy metal content of the humus soil does not exceed the standard, and meets the requirements of GB 16889-2024. The supernatant of the sedimentation tank and the dehydrator effluent are recycled into the deodorization system for recycling.

[0062] This embodiment not only treats the garbage leachate, but also improves the product performance of the humus soil by converting the humic acid in the garbage leachate into solid phase and entering the solid phase humus soil, and greatly improves the calorific value of the waste plastic and increases the added value of the waste plastic.

[0063] For about 30,000 tons of garbage leachate in the landfill area of a county, the coupling method described in this embodiment is used for treatment, and the total treatment cost (mainly equipment investment) is about 3 million yuan. About 40,000 tons of humus soil with a water content of about 60wt% are sold to generate about 1 million yuan of economic benefits, and the overall net treatment cost is 2 million yuan. It can be seen that compared with the foregoing treatment methods for garbage leachate and waste plastic respectively, the total treatment cost of the coupling method of this embodiment is greatly reduced.

[0064] In summary, the coupling method of the application is that landfill leachate is removed volatile odor by aerobic aeration, then enters the waste plastic washing device, washes the mud adhered to the waste plastic, the washing liquid is separated into solid humus and liquid water by dehydration device after precipitation, the liquid water is recycled into the waste plastic washing device to reduce water consumption; the solid humus adsorbs the refractory humus in the leachate. The application not only realizes the reduction and recycling of leachate, improves the added value of waste plastic, but also fully utilizes the characteristics of landfill system, solves the problem of leachate treatment of garbage pile.

[0065] The application is described by the above embodiments to illustrate the detailed structural features of the application, but the application is not limited to the above detailed structural features, that is, it does not mean that the application must rely on the above detailed structural features to be implemented. It should be understood by those skilled in the art that any improvement of the application, equivalent replacement of the selected components of the application, addition of auxiliary components, selection of specific modes, etc. fall within the protection scope and disclosure scope of the application.

[0066] The preferred embodiments of the application are described in detail above, but the application is not limited to the specific details in the above embodiments, and within the technical concept scope of the application, the technical solutions of the application can be variously modified, and these simple modifications all belong to the protection scope of the application.

[0067] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the application will not further describe various possible combination manners.

[0068] In addition, various different embodiments of the application can also be combined in any manner, as long as it does not deviate from the idea of the application, and it should also be considered as the disclosed content of the application.

Claims

1. A coupled method for washing waste plastics and recovering humus soil using landfill leachate, characterized by, The coupling method comprises the following steps: The leachate is deodorized to obtain deodorized leachate; the waste plastics separated by excavation, screening and sorting of the landfill are crushed, the crushed particle size is below 10 cm, then the crushed waste plastics enter the spiral desludging machine and are mixed with the deodorized leachate for desludging, the rotation speed of the spiral desludging machine is controlled to be 300-700 rpm, and the mass ratio of the deodorized leachate to the waste plastics is controlled to be (1-10):1, to obtain desludged plastics and desludged slurry; The desludged plastics are sequentially dehydrated and dried to obtain clean dry plastics; the desludged slurry is subjected to solid-liquid separation, the obtained liquid phase is recycled to deodorization, and the obtained solid phase is recycled as humus soil; wherein the odor concentration of the deodorized leachate is below 10.

2. The coupled method of washing waste plastics and recovering humus soil using landfill leachate according to claim 1, characterized in that, The deodorization comprises any one or a combination of at least two of biochemical treatment, strong oxidation treatment or mineralized waste adsorption treatment.

3. The method according to claim 1, wherein the method is characterized by, The dehydration is performed by using a high-speed dehydrator, and the rotation speed thereof is controlled to be 2500-3000 rpm; And / or, the moisture content of the dehydrated plastics obtained by dehydration is 4-10 wt%. 4.The method according to claim 1, wherein, The solid-liquid separation comprises sequential standing precipitation and dehydration, and the recovered water obtained by the standing precipitation and the dehydration is recycled to the deodorization. 5.The method for washing waste plastics and recovering humus soil using landfill leachate according to claim 1, wherein, The moisture content of the humus soil is 10-70 wt%.

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