Humus soil mixed filler for treating leachate, preparation method and application thereof

Abstract

The application discloses a humus soil mixed filler for treating leachate, a preparation method and application, and belongs to the field of environmental protection. The humus soil mixed filler is formed by mixing humus soil and an adsorbent at a mass ratio of 1:1-1:2. The humus soil is mainly formed by biological straw, sawdust and urea after fermentation and complete humification. The mass ratio of the biological straw and the sawdust is 4:1-2:1, and the urea accounts for 1-2% of the total mass of the humus soil. The mass ratio of carbon and nitrogen in the humus soil is (20-30):1. The adsorbent is viscous soil which is dried in the air, then crushed into particles with a particle size of 100-200 meshes. The mixed filler contains rich microorganisms, can degrade and adsorb the pollutants in the leachate, and can efficiently remove the pollutants in the leachate. Meanwhile, the raw materials of the mixed filler are cheap and easy to obtain, the mixed filler is convenient to make, the use effect is remarkable, and the mixed filler is convenient to popularize and generalize.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of sewage treatment and environmental protection, and particularly relates to a humus soil mixed filler for treating leachate, a preparation method and application thereof, and mainly to an anaerobic treatment process. BACKGROUND

[0002] With the continuous expansion of the scale of cities in China, the number of urban population is increasing year by year, and the amount of municipal solid waste is also gradually increasing. In China, municipal solid waste is mainly treated by landfill process, which leads to the problem of leachate pollution. According to the statistics of relevant research departments, the current leachate production in China has reached more than 30 million tons per year. The high concentration of ammonia nitrogen and COD in leachate can cause oxygen deficiency and water quality deterioration of surface water; nitrogen and phosphorus nutrients can lead to water eutrophication, which seriously affects the drinking water source of residents. Therefore, the treatment of leachate has become one of the difficulties and focuses of attention and research of domestic and foreign scholars.

[0003] At present, the treatment methods of leachate can be divided into biological method, physicochemical method, land method and the combination of different methods. Among them, the biological method is the most commonly used method in leachate treatment. Because its operation and treatment cost is relatively low compared with the physicochemical method, the organic matter is mainly degraded by microorganisms to generate carbon dioxide, water, methane and microorganisms, which have little effect on the environment (methane gas can be used as energy recovery), and there is no problem of secondary pollution caused by chemical sludge. Therefore, it is widely used in the world. The anaerobic treatment process is the front treatment unit in the whole biological treatment system, which is very important for the stable operation and discharge of the subsequent process. Humus soil is a new generation of filler for anaerobic treatment process, which has been applied in a small amount abroad. However, due to the difference of sewage quality, the technology still has the problem of adaptability in China. The single humus soil has too large porosity and too fast flow rate, which is easy to cause short flow and poor treatment effect.

[0004] Therefore, the present application provides a humus soil mixed filler for treating leachate, a preparation method and application thereof to overcome the defects of the prior art. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art, and provides a humus soil mixed filler for treating leachate, a preparation method and application thereof. The raw materials of the humus soil mixed filler are cheap and easy to obtain, and the filler is easy to make. When the leachate passes through the mixed filler, it can not only be reduced by microorganisms, but also be adsorbed, so that various pollutants in the leachate can be efficiently removed.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] In one aspect, a humus mixed filler for treating leachate is provided, which comprises uniformly mixed humus and adsorbent, and the mass ratio of the humus to the adsorbent is 1:1-1:2.

[0008] The adsorbent is a wind-dried and crushed clay particle.

[0009] The humus is mainly formed by biological straw, sawdust and urea after fermentation and complete humification, the mass ratio of the biological straw to the sawdust is 4:1-2:1, and the urea accounts for 1-2% of the total mass of the humus.

[0010] The humus in the application contains rich organic matter and nutrient elements, can provide growth and reproduction for hundreds of millions of microorganisms, has the characteristics of light soil, large void and large specific surface area, can be used as a carrier of a biological membrane, and enables microorganisms to adhere and grow to form a biological membrane, so that the microorganisms can efficiently degrade various pollutants in wastewater (leachate) when the wastewater flows through.

[0011] Further, the clay used as the adsorbent is wind-dried and then crushed into particles with a particle size of 100-200 mesh.

[0012] Further, the mass ratio of carbon to nitrogen in the humus is (20-30):1.

[0013] In a second aspect, the application provides a preparation method of the above-mentioned humus mixed filler, which comprises the following steps:

[0014] Step one, preparation of humus: uniformly mix crushed biological straw and sawdust at a mass ratio of 4:1-2:1, then add a set amount of water, and then add urea accounting for 1-2% of the total mass of the humus, so that the mass ratio of carbon to nitrogen in the humus is controlled to be (20-30):1, turn the pile once every 7 days while supplementing water, and naturally ferment for 30-45 days, until complete humification, to obtain the humus;

[0015] Step two, preparation of adsorbent: take a set amount of clay, and wind-dry and crush it into particles with a particle size of 100-200 mesh;

[0016] Step three: fully mix the humus prepared in step one and the adsorbent prepared in step two at a set ratio, to obtain the humus mixed filler.

[0017] Further, the humidity is required to be 65-75% after adding the set amount of water in step one.

[0018] Further, the mass ratio of the humus to the adsorbent in step three is 1:1-1:2.

[0019] In a third aspect, the present application provides an application of the humus mixed filler, which is obtained according to the preparation method, and is used for treating landfill leachate in an anaerobic reactor.

[0020] Further, the humus mixed filler is placed in a middle position in the anaerobic reactor during the application, a water distributor is arranged on the upper part of the humus mixed filler, and a supporting layer is arranged on the lower part of the humus mixed filler; during the use, the landfill leachate to be treated enters from the top inlet of the anaerobic reactor, is then uniformly distributed on the upper part of the humus mixed filler by the water distributor, and is treated by the humus mixed filler and the supporting layer in sequence, and then flows out from the water outlet at the bottom of the anaerobic reactor.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] The humus mixed filler for treating leachate, the preparation method and the application provided by the present application are mixed by humus and adsorbents. The adsorbents are clay particles after air-drying and crushing, and have the characteristics of large specific surface area. The humus is mainly formed by biological straw, sawdust and urea after fermentation and complete humification, and thus contains a large number of microorganisms. Therefore, the humus mixed filler can not only degrade various pollutants in the landfill leachate, but also adsorb the pollutants in the landfill leachate by the adsorption function of the humus and the adsorbents in the mixed filler. Compared with the prior art, the present application improves the defects of the single humus filler, such as too large porosity, too fast flow rate and poor treatment effect, and uses clay to reduce the porosity, slow down the water flow rate, improve the removal rate, and ensure the efficient and stable operation of the anaerobic treatment process. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which are incorporated into and form a part of the specification, are used to explain the principles of the present application together with the specification.

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained from these drawings without any creative labor.

[0025] Figure 1 is a flow chart of the preparation method of the humus mixed filler of the present application;

[0026] Figure 2 is a physical diagram of the humus of the present application;

[0027] Figure 3 is a structure schematic diagram of the application of the humus mixed filler of the present application.

[0028] Wherein: 1 is an anaerobic reactor; 2 is a water distributor; 3 is a humus mixed filler; 4 is a supporting layer; 11 is a water inlet; and 12 is a water outlet. DETAILED DESCRIPTION

[0029] The exemplary embodiments will be described in detail herein with reference to the accompanying drawings. In the following description, unless otherwise indicated, like numbers in the different drawings represent the same or similar elements. The following exemplary embodiments described in this specification are not meant to represent all implementations consistent with the present application. Rather, they are simply examples of apparatuses consistent with some aspects of the present application as detailed in the appended claims.

[0030] In order to make the technical solution of the present application better understood by those skilled in the art, the present application will be further described in detail below with reference to the accompanying drawings and examples.

[0031] As shown in Figure 1 The present application provides a preparation method of a humus mixed filler for treating leachate, which specifically comprises the following steps:

[0032] 1) Preparation of humus: uniformly mix crushed biological straw and sawdust at a mass ratio of 4:1 to 2:1, then add a set amount of water to make the humidity reach 65% to 75%, and then add 1% to 2% of urea based on the total mass of the humus to control the mass ratio of carbon and nitrogen in the humus to be (20 to 30):1, turn the pile once every 7 days while supplementing water, and naturally ferment for 30 to 45 days, until complete humification, to obtain the humus.

[0033] Among them, the biological straw used in the present application can be common straw such as corn, wheat, and rice straw, and there is no detailed requirement for the biological straw; the sawdust also has no strict requirement for the type of tree. The biological straw is crushed by a rubbing machine, with a size of 3 to 10 cm, and the sawdust is crushed by a crushing machine, with a size of 1 to 3 cm. The biological straw should not be too small, because the biological straw has a supporting effect in the fermentation pile, and being too small is not conducive to the entry of oxygen into the fermentation pile and fermentation. The sawdust is difficult to ferment, and cannot be too large, as it is difficult to degrade.

[0034] Due to the easy fermentation of biological straw and the difficult degradation of sawdust, it is necessary to mix the biological straw and sawdust at a suitable ratio to ensure the fermentation efficiency and fermentation temperature. Too much sawdust may result in insufficient fermentation temperature and immature fermentation.

[0035] The main role of water in the pile is to dissolve organic matter and participate in the metabolism of microorganisms. At the same time, through water evaporation, it also plays a role in regulating the temperature of the pile. Therefore, the change of the moisture content of the pile directly affects the growth and metabolism process of microorganisms, and affects the reaction speed and composting degree of the compost. If the moisture content is too high, the pile will be compacted or the internal free space will be filled with water film, which will reduce the free space rate and hinder air diffusion and transportation, resulting in a large number of anaerobic conditions, hindering the aerobic metabolism of microorganisms, and producing odor; if the moisture content is too low, the growth and reproduction of microorganisms will also be affected, and the composting reaction speed will be reduced.

[0036] A certain amount of urea is added to adjust the carbon-nitrogen ratio. The appropriate C:N ratio for fermentation is (20-30):1. If the C / N ratio is too high, the nitrogen element required for the growth and reproduction of microorganisms will be limited, the reproduction speed of microorganisms will be low, the decomposition speed of organic matter will be slow, the fermentation time will be long, and the humification coefficient of the compost will be low, resulting in poor fermentation of the compost. If the C / N ratio is too low, the energy source required for the growth and reproduction of microorganisms will be limited, the fermentation temperature will rise slowly, nitrogen will be released in the form of ammonia gas, organic nitrogen will be lost, and unpleasant odors will be emitted.

[0037] Since the humus soil is composed of biological straw, sawdust and urea and is formed by fermentation, the humus soil contains rich organic matter and nutrient elements, can provide growth and reproduction for hundreds of millions of microorganisms, and has the characteristics of light soil, large void and large specific surface area, can be used as a carrier of biological membrane, makes microorganisms adhere and grow to form a biological membrane, and when wastewater flows through, the microorganisms can degrade pollutants in the wastewater.

[0038] 2) Preparation of adsorbent: a certain amount of clay is taken and dried, crushed to a particle size of 100-200 mesh, so as to enlarge the specific surface area of the filler. In the present application, 100-200 mesh particles are used, because if the particle size is too large, the specific surface area is small, the adsorption effect of the filler on pollutants is poor, and the removal rate will be reduced; and if the particle size is too small, it is easy to block and also causes loss as the water flow flows out of the reactor.

[0039] 3) The humus soil prepared in step 1) and the adsorbent prepared in step 2) are mixed in a ratio of 1:1-1:2, i.e. the humus soil mixed filler as shown in Figure 2 The ratio of humus soil to adsorbent is 1:1-1:2, because if the ratio of humus soil to adsorbent is too large, the porosity of the filler will be too large, the water flow rate will be too fast, short flow will easily occur, and the treatment effect will not be good. If the ratio of humus soil to adsorbent is too small, the clay particles will easily stick together and block, on the other hand, too little humus soil may not provide enough nutrients for the growth and metabolism of microorganisms.

[0040] Because the mixed filler contains a large amount of microorganisms and has a large specific surface area of silt adsorbent, the two have a synergistic effect, which can not only degrade the pollutants in the landfill leachate, but also the humus soil and the adsorbent in the filler can adsorb the pollutants in the landfill leachate, so that the mixed filler has the effects of microbial degradation and adsorption, and therefore can efficiently remove the pollutants in the landfill leachate.

[0041] In addition, the application provides an application of the humus soil mixed filler, which is used for treating landfill leachate in an anaerobic reactor. Figure 3 As shown in the figure, the humus soil mixed filler 3 prepared by the application is placed in the middle position of the anaerobic reactor 1, a water distributor 2 is arranged on the upper part of the humus soil mixed filler 3, and a supporting layer 4 is arranged on the lower part of the humus soil mixed filler 3, preferably, the supporting layer 4 is sand, and in order to accelerate the degradation of pollutants in the landfill leachate, a temperature control system can also be arranged; during use, the landfill leachate to be treated enters from the top inlet 11 of the anaerobic reactor 1, then is uniformly distributed on the upper part of the humus soil mixed filler 1 by the water distributor 2, and then is treated by the humus soil mixed filler 3 and the supporting layer 4 in turn, and finally flows out from the water outlet 12 at the bottom of the anaerobic reactor 1.

[0042] In order to further verify the use effect of the humus soil mixed filler, the inventors carried out the following specific examples for testing.

[0043] Example 1

[0044] In this embodiment, the humus soil and the adsorbent are mixed at a ratio of 1:1, 50g of the particle cohesive soil particles and 50g of the humus soil which are crushed to 100 mesh are respectively taken, and the two are fully mixed and uniformly distributed, so as to obtain 100g of the humus soil mixed filler.

[0045] Then, according to the principle of the anaerobic reactor, a small test micro anaerobic reactor is made, 100g of the humus soil mixed filler is placed in the middle of the micro anaerobic reactor, and sand is placed below as a supporting layer, and the structure is as shown in the figure. Figure 3 During the test, 100mL of the landfill leachate to be treated is dripped into the micro anaerobic reactor every day, and the flow rate is controlled by a dropper (equivalent to a water distributor), so that it is dripped for 5 hours. At the same time, the pH value, COD, NH3-N and TP of the inlet and outlet leachate are monitored, and the duration of this test is 29 days. The experimental results are shown in Table 1.

[0046] Table 1 Experimental results

[0047]

[0048]

[0049] From the experimental data of Table 1, it can be seen that the COD removal rate of the leachate to be treated after passing through the humus soil mixed filler of the present application is 70.6%, the NH3-N removal rate is 36.6%, and the TP removal rate is 47.5%. It can be seen that the humus soil mixed filler of the present application has good treatment effect on leachate.

[0050] Example 2

[0051] In this embodiment, the humus soil and the adsorbent are mixed at a ratio of 1:1.5. 3 kg of humus soil is weighed, 4.5 kg of 150-mesh granular clay is crushed, and the two are thoroughly mixed to obtain 5.5 kg of humus soil mixed filler.

[0052] The effective volume of the reactor in this test is 7.935 L. The COD concentration of the influent landfill leachate fluctuates in the range of 650-1500 mg / L, the NH3-N concentration is in the range of 15-25 mg / L, the TP concentration is in the range of 3-8 mg / L, the temperature is between 10-20℃, the influent pH value is between 7.2-7.85, and the HRT is 16 h.

[0053] The test is continuously operated for 1 month. It is determined that there is no significant difference between the influent and effluent pH values, the COD removal rate is 70%-85%, and the NH3-N and TP removal rates are both 30-40%.

[0054] Comparative Example

[0055] The difference between the comparative example and Example 2 is that in the comparative example, the humus soil and the adsorbent are mixed at a ratio of 1:3. 3 kg of humus soil is weighed, 9 kg of 150-mesh granular clay is crushed, and the two are thoroughly mixed to obtain 12 kg of humus soil mixed filler.

[0056] The effective volume of the reactor in this test is 7.935 L. The COD concentration of the influent landfill leachate fluctuates in the range of 650-1500 mg / L, the NH3-N concentration is in the range of 15-25 mg / L, the TP concentration is in the range of 3-8 mg / L, the temperature is between 10-20℃, the influent pH value is between 7.2-7.85, and the HRT is 16 h.

[0057] The test is continuously operated for 1 month. It is determined that there is no significant difference between the influent and effluent pH values, the COD removal rate is 70%-85%, and the NH3-N and TP removal rates are both 30-40%.

[0058] Example 3

[0059] In the embodiment, the humus soil and the adsorbent are mixed at a ratio of 1:2, 2 kg of humus soil is weighed, 4 kg of 200-mesh granular clay soil is crushed, and the two are mixed evenly to obtain 6 kg of humus soil mixed filler.

[0060] The effective volume of the reactor in the test is 8.3657 L, the COD concentration of the influent landfill leachate fluctuates in the range of 700-1450 mg / L, the NH3-N concentration is in the range of 20-30 mg / L, the TP concentration is in the range of 4-10 mg / L, the temperature is between 5-25 ℃, the influent pH value is between 6.3-7.4, and the HRT is 18 h.

[0061] The test is stably and continuously operated for 1 month, and it is determined that there is no obvious difference between the influent and the effluent pH, the COD removal rate is in the range of 70%-80%, and the NH3-N and TP removal rates are both in the range of 35-40%.

[0062] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application.

[0063] It should be understood that the present application is not limited to the above-described and that various modifications and changes can be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A humic soil mixed filler for treatment of leachate, characterized in that, The humus soil mixed filler comprises uniformly mixed humus soil and adsorbent, and the mass ratio of the humus soil to the adsorbent is 1:1 to 1:2; The adsorbent is air-dried and crushed clay particles, and the particle size of the clay particles is 100 to 200 mesh; The humus soil is mainly formed by fermentation and complete humification of biological straw, sawdust and urea, the mass ratio of the biological straw to the sawdust is 4:1 to 2:1, and the urea accounts for 1% to 2% of the total mass of the humus soil; the mass ratio of carbon to nitrogen in the humus soil is (20-30):1, the particle size of the crushed biological straw is 3-10 cm, the particle size of the crushed sawdust is 1-3 cm, the material is turned over every 7 days during the fermentation process, the natural fermentation time is 30-45 days, and the material humidity is controlled at 65%-75% during the fermentation process; The humus soil mixed filler is used for treating landfill leachate in an anaerobic reactor, the humus soil mixed filler is placed in the middle of the anaerobic reactor, a water distributor is arranged above the humus soil mixed filler, and a supporting layer is arranged below the humus soil mixed filler; during use, the landfill leachate to be treated enters from the top inlet of the anaerobic reactor, then is uniformly distributed above the humus soil mixed filler by the water distributor, and finally flows out from the bottom outlet of the anaerobic reactor after being treated by the humus soil mixed filler and the supporting layer.

2. The method for preparing the humus mixed filler according to claim 1, characterized in that, The preparation method comprises the following steps: Step 1: preparation of humus soil: uniformly mix crushed biological straw and sawdust at a mass ratio of 4:1 to 2:1, then add a certain amount of water, and then add urea accounting for 1% to 2% of the total mass of the humus soil, so that the mass ratio of carbon to nitrogen in the humus soil is controlled at (20-30):1, turn over every 7 days, and supplement water, and then naturally ferment for 30-45 days to obtain humus soil after complete humification; Step 2: preparation of adsorbent: take a certain amount of clay, and air-dry and crush the clay into particles with a particle size of 100-200 mesh; Step 3: mix the humus soil prepared in step 1 and the adsorbent prepared in step 2 according to a certain proportion to obtain the humus soil mixed filler.

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