Production method and application of organic-inorganic composite cured particle humic filler

Abstract

The invention discloses a production method of an organic-inorganic composite solidified particle humic filler. The method comprises the following steps: fully mixing sieved humus soil, fly ash, slaked lime or carbide slag in a stirrer, wherein the storage amount of domestic garbage is more than 5 years after field sealing; diluting an organic adhesive which takes polyvinyl alcohol as a main component; directly adding the diluted organic adhesive solution into the mixed material, continuously stirring for 5-10 minutes, and controlling the water content of the mixed material to be 30-40%; and conveying the treated mixed material to granulation equipment for granulation, and naturally curing for 1-3 days to obtain the composite cured granular humic filler. The finally formed granular product has both mechanical properties and biological activity, is suitable for standard filler replacement in various water treatment fields, realizes a new way of large-scale resource utilization of the undersize humus soil, and is of great significance to promotion of resource recycling and improvement of ecological environment.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental engineering water treatment and odor treatment, and relates to a method for producing a granular humic filler, and in particular to a method for producing and applying an organic-inorganic composite solidified granular humic filler. Background Art

[0002] China's rapid urbanization has led to a rapid increase in the amount of domestic waste in cities. Landfill technology has been the main form of domestic waste treatment for a long time. Currently, the total amount of waste in the country exceeds 8 billion tons, occupying more than 500 million m 2 Due to the widespread environmental pollution risks posed by existing domestic waste, the large amount of land occupied affects the construction and development of surrounding cities, and the current domestic waste treatment technology, which mainly relies on incineration power generation technology, still requires landfill capacity to solve problems such as fly ash landfill and emergency landfill. Therefore, the development of existing domestic waste mining, sorting and resource utilization technology is of great practical significance.

[0003] After mining and sorting existing municipal solid waste, three main categories of products are formed: undersize humus, oversize light material, and oversize heavy material. Humus accounts for the largest proportion (40-50%), but realizing the large-scale resource utilization of undersize humus has been an unresolved technical challenge.

[0004] The Chinese invention patent (application number 202010363502.6, published on August 14, 2020) applied for and authorized by our team discloses a method for producing and applying granular humic biofill. This technology utilizes high-pressure atomization of sieved humus soil pellets, followed by coating and curing with an organic binder, polyvinyl alcohol, to produce spherical granules with mechanical strength and good water resistance. This addresses the problem of traditional humic fillers settling and compacting in water. While the organic binder in these granular humic biofills does not biodegrade within six months of use, it does after 3-5 years, leading to elevated effluent COD concentrations and hindering their widespread application. Summary of the Invention

[0005] The problems to be solved by the present invention include but are not limited to: (1) The existence of COD dissolution caused by biodegradation of the adhesive and the subsequent lack of mechanical strength in pure organic curing technology Due to microbial degradation, organic binders lead to insufficient subsequent mechanical strength of the particles, which may cause the filler layer to settle and compact; the degradation products of the binder are dissolved in the form of COD, affecting the water quality of the effluent.

[0006] (2) Humus soil raw materials may have secondary pollution problems caused by excessive heavy metals While household waste humus soil typically doesn't contain excessive levels of heavy metals, this can occur if there's irregular dumping of industrial solid waste or excessive levels of heavy metals in the fuel of waste transfer vehicles. However, existing organic solidification granular humus biofill technology only provides initial mechanical strength but doesn't guarantee effective fixation of heavy metals. Therefore, there's a risk of secondary heavy metal contamination during the use of the granular filler.

[0007] In order to solve the above-mentioned problems such as poor biological stability of simple organic solidification technology, the present invention has developed a production method for organic-inorganic composite solidified granular humic filler. The produced granular humic filler product has the advantages of suitable mechanical strength, good water resistance, high biological activity and long-term stability, and opens up a new and reliable path for the large-scale resource utilization technology of under-screen humus soil.

[0008] The technical principles of the present invention are as follows: The present invention utilizes the composite solidification technology of organic binder and inorganic solidifier (industrial solid waste such as fly ash and carbide slag) to produce organic-inorganic composite solidified granular humic filler, thereby achieving a combination of rapid early composite structural strength and long-term stable inorganic structural strength of the granular humic filler. At the same time, the mild composite solidification conditions retain the performance advantages of organic matter and microorganisms in the humus soil raw materials, and can also effectively fix any heavy metal ions that may be present.

[0009] Among them, regarding the early composite structure strength and long-term stable inorganic structure strength: (1) In the early stage, the organic binder provides part of the initial structural strength with a high molecular network structure. At the same time, the main component of slaked lime or carbide slag, calcium hydroxide, undergoes carbonization reaction, and the generated CaCO3 crystals further enhance the mechanical strength and water resistance of the particles.

[0010] (2) In the long term, the active SiO2 and Al2O3 components in fly ash undergo a pozzolanic reaction in an alkaline environment with the presence of water, generating hydraulically hardened gelling compounds that fill the gaps between particles and provide long-term stable inorganic structural strength.

[0011] Among them, regarding the effective fixation of heavy metals: (1) The added calcium hydroxide of carbide slag or slaked lime causes heavy metal ions to form hydroxide precipitates under alkaline conditions through ion exchange; (2) The added fly ash has many silicon and aluminum active sites that can adsorb heavy metal ions and convert them into stable forms; The above two factors work together to achieve the solidification and stabilization of heavy metal ions and reduce the risk of secondary heavy metal pollution.

[0012] The technical solutions of the present invention are as follows: A method for producing an organic-inorganic composite solidified granular humic filler comprises the following steps: (1) The humus soil (drum screen aperture 30mm-50mm, mass ratio of about 75%-90%) under the screen of the domestic waste that has been closed for more than 5 years, fly ash (mass ratio of about 5%-20%), slaked lime or calcium carbide slag (mass ratio of about 5%-10%) are fully mixed in a mixer. At the same time, the organic binder with polyvinyl alcohol as the main component is diluted to a mass concentration of 1%-5% and then directly added to the above-mentioned mixture. Stirring is continued for 5-10 minutes. The moisture content of the mixture is controlled to 30%-40%; (The mass percentages of the undersize humus soil, fly ash, slaked lime or carbide slag are 75% to 90%, 5% to 20% and 5% to 10% respectively. This formula can adjust the moisture content and ensure the particle strength).

[0013] (2) The mixed material after the treatment in step (1) is transported to a granulation device such as a disc granulator to form spherical particles with a particle size of 1 mm to 10 mm, and then discharged for natural curing for 1 to 3 days to obtain a composite solidified granular humic filler.

[0014] The invention discloses an organic-inorganic composite solidified particle humic filler. The filler is prepared according to the above-mentioned production method of the organic-inorganic composite solidified particle humic filler.

[0015] The application of organic-inorganic composite solidified granular humic filler can be used in sewage treatment and odor treatment processes of biological fillers.

[0016] The beneficial effects of the present invention are: (1) The organic-inorganic composite solidification technology of the present invention enables the granular humic filler to form early composite structural strength after granulation, and is not affected by belt conveying and ton bag packaging and stacking; the volcanic ash activity of the material components can be used to form long-term stable inorganic structural strength during the temporary storage or transportation process of the granular humic filler packaging, which is convenient for long-term storage or immediate use.

[0017] (2) The present invention replaces the bentonite in the background patent with auxiliary materials (fly ash, slaked lime or carbide slag). The moisture content of the mixture can be controlled by the auxiliary materials. After sufficient mixing, granulation (particle size is 1mm to 10mm) is carried out. Not only does the adhesion problem no longer need to be considered, but the auxiliary materials act as inorganic curing agents. While enhancing the mechanical strength of the particles, the fly ash and other alkaline components can effectively fix heavy metal ions, providing a safer guarantee for the promotion and application of granular humic fillers.

[0018] (3) The present invention uses an organic adhesive with polyvinyl alcohol as the main component to replace the polyvinyl alcohol glue in the background patent, which has good biodegradability and avoids the problem of COD dissolution caused by microbial degradation. DETAILED DESCRIPTION

[0019] The present invention will be further described below with reference to the embodiments.

[0020] Example 1

[0021] The production method of the improved granular humic filler of this embodiment specifically comprises the following steps: (1) The humus soil under the screen of the domestic waste that has been closed for more than 5 years (the humus soil under the screen of the domestic waste that has been closed for more than 5 years, whose components have reached the stabilized effect) (drum screen aperture 30mm~50mm, mass ratio 85%), fly ash (mass ratio 10%), and calcium carbide slag (mass ratio 5%) are fully mixed in a mixer. At the same time, the organic binder with polyvinyl alcohol as the main component is diluted to a mass concentration of 1% and then added to the mixture. The mixture is stirred for 10 minutes and the moisture content of the mixture is controlled to 35%; In this embodiment, the organic adhesive with polyvinyl alcohol as the main component is 901 construction glue, which is diluted to a mass concentration of 1% before use after purchase.

[0022] (2) The mixed material after the treatment in step (1) is transported to a granulation device such as a disc granulator to form spherical particles with a particle size of 1 mm to 10 mm, and then discharged for natural curing for 1 to 3 days to obtain a composite solidified granular humic filler.

[0023] Example 2

[0024] The production method of the improved granular humic filler of this embodiment specifically comprises the following steps: (1) The humus soil under the screen of the domestic waste that has been closed for more than 5 years (the humus soil under the screen of the domestic waste that has been closed for more than 5 years, whose components have reached the stabilized effect) (the drum screen aperture is 30mm~50mm, the mass ratio is 75%), fly ash (mass ratio is 19%), and slaked lime (mass ratio is 6%) are fully mixed in a mixer. At the same time, the organic binder with polyvinyl alcohol as the main component is diluted to a mass concentration of 1% and then added to the mixture. The mixture is stirred for 10 minutes and the moisture content of the mixture is controlled to 35%; In this embodiment, the organic adhesive with polyvinyl alcohol as the main component is 901 construction glue, which is diluted to a mass concentration of 1% before use after purchase.

[0025] (2) The mixed material after the treatment in step (1) is transported to a granulation device such as a disc granulator to form spherical particles with a particle size of 1 mm to 10 mm, and then discharged for natural curing for 1 to 3 days to obtain a composite solidified granular humic filler.

[0026] Example 3

[0027] The production method of the improved granular humic filler of this embodiment specifically comprises the following steps: (1) The humus soil under the screen of the domestic waste that has been closed for more than 5 years (the humus soil under the screen of the domestic waste that has been closed for more than 5 years, whose components have reached the stabilized effect) (drum screen aperture 30-50mm, mass ratio 90%), fly ash (mass ratio 5%), and calcium carbide slag (mass ratio 5%) are fully mixed in a mixer. At the same time, the organic binder with polyvinyl alcohol as the main component is diluted to a mass concentration of 1% and then added to the mixture. The mixture is stirred for 10 minutes and the moisture content of the mixture is controlled to 35%; In this embodiment, the organic adhesive with polyvinyl alcohol as the main component is 901 construction glue, which is diluted to a mass concentration of 1% before use after purchase.

[0028] (2) The mixed material after the treatment in step (1) is transported to a granulation device such as a disc granulator to form spherical particles with a particle size of 1 mm to 10 mm, and then discharged for natural curing for 1 to 3 days to obtain a composite solidified granular humic filler.

[0029] The humic filler formed after the production method of the above embodiment of the present invention is modified has excellent mechanical properties, good water resistance and high microbial activity. When used as a biofilter filler, the granular humic filler is stable for a long time and does not loosen.

[0030] The humic filler prepared in the above embodiment was subjected to performance testing, and the results were as follows: (1) Particle physical properties The particle size of the spherical particles is between 1mm and 10mm. The initial structural strength meets the requirements of belt conveying and ton bag stacking. The structural strength is significantly improved after 1 to 3 days of natural curing.

[0031] (2) Particle leaching experiment A leaching column with an inner diameter of 35 mm was filled with 500 g of composite solidified granular humic filler, and tap water was added from top to bottom using a peristaltic pump for continuous leaching. The effluent mixed water samples were collected every 12 hours, and the conventional water quality indicators of the effluent were tested.

[0032] The 12-hour leaching effluent had an ammonia nitrogen concentration of 5.8 mg / L, a total nitrogen concentration of 15.5 mg / L, a total phosphorus concentration of 0.7 mg / L, a COD concentration of 96 mg / L, and a pH of 10.51. The 24-hour leaching effluent had an ammonia nitrogen concentration of 3.1 mg / L, a total nitrogen concentration of 11.2 mg / L, a total phosphorus concentration of 0.4 mg / L, a COD concentration of 69.33 mg / L, and a pH of 9.71. The ammonia nitrogen, total nitrogen, and total phosphorus concentrations met the Class A standard of the Pollutant Discharge Standard for Municipal Wastewater Treatment Plants (GB 18918-2002). The 48-hour leaching effluent had a COD concentration of 48 mg / L and a pH of 8.87, fully meeting the Class A standard. (3) Film forming performance test A simulated biofilter was constructed using a PVC pipe with an inner diameter of 40 mm and a height of 600 mm. The filler was filled to a height of 500 mm and the biofilm was formed naturally by domestic sewage. The device was operated intermittently, with a flooding and drying time ratio of 1:4 and an inlet hydraulic load of 1.0 m 3 / (m 2 d) Natural ventilation. Measure the COD and NH4 of the inlet and outlet water every day. + -N concentration.

[0033] On the third day of operation, the COD removal rate was basically stable at 60%-70%; on the fourth day, NH4 + The -N removal rate is stable at 25%-30%, which proves that the organic-inorganic composite solidified granular humic filler prepared in the above embodiment has the advantages of fast startup speed and stable biodegradation effect.

[0034] Comparative Example 1: The production method of the granular humic filler of this comparative example specifically comprises the following steps: (1) Put the humus soil (drum screen aperture 30mm-50mm) under the sieve of the domestic garbage that has been closed for more than 5 years into the mixer, and dilute the organic binder with polyvinyl alcohol as the main component to 5% mass concentration and add the humus soil. Stir for 10 minutes and control the moisture content of the material to 35%; Among them, the organic adhesive with polyvinyl alcohol as the main component is 901 construction glue, which is diluted to a mass concentration of 5% after purchase.

[0035] (2) The mixed material after the treatment in step (1) is transported to a granulation device such as a disc granulator to form spherical particles with a particle size of 1 mm to 10 mm, and then discharged for natural curing for 3 days to obtain an organic solidified granular humic filler.

[0036] The granular humic filler produced in Comparative Example 1 contains only humus and organic binder as raw materials. The humic acid and other substances in the humus dissolve to make the pH of the leachate acidic. Moreover, since no fly ash is added, the pozzolanic reaction cannot occur and therefore the granular humic filler cannot exist stably for a long time.

[0037] Comparative Example 2: The production method of the granular humic filler of this comparative example specifically comprises the following steps: (1) The humus soil (drum screen aperture 30mm-50mm, mass ratio 70%) under the screen of the domestic waste that has been closed for more than 5 years, fly ash (mass ratio 15%), and calcium carbide slag (mass ratio 15%) are fully mixed in a mixer. At the same time, the organic binder with polyvinyl alcohol as the main component is diluted to 5% mass concentration and added to the mixture. The mixture is stirred for 10 minutes and the moisture content of the mixture is controlled to 30%; Among them, the organic adhesive with polyvinyl alcohol as the main component is 901 construction glue, which is diluted to a mass concentration of 5% after purchase.

[0038] (2) The mixed material after the treatment in step (1) is transported to a granulation device such as a disc granulator to form spherical particles with a particle size of 1 mm to 10 mm, and then discharged for natural curing for 3 days to obtain a composite solidified granular humic filler.

[0039] In Comparative Example 2, the mass ratio of carbide slag in the granular raw material is relatively high. Although the granular filler can exist stably for a long time, the pH of the granular leachate is relatively high, which is not conducive to microbial growth and biofilm formation, and is not suitable for use as a water treatment filler.

[0040] The steps described in the above specific implementation scheme are only for illustrating implementation cases in the process of the present invention. For ordinary technicians in this field, as long as they are within the scope of the essence of the present invention, any changes and modifications to the above implementation cases fall within the scope of the claims of the present invention.

Claims

1. A method for producing an organic-inorganic composite solidified granular humic filler, characterized in that: The method comprises: (1) Thoroughly mix the humus soil sieved from the domestic waste stored in the closed site for more than 5 years with fly ash, slaked lime or calcium carbide slag in a mixer; (2) diluting the organic binder with polyvinyl alcohol as the main component; (3) Add the diluted organic binder solution directly to the mixture in step (1), continue stirring for 5 to 10 minutes, and control the moisture content of the mixture to 30% to 40%; (4) The mixed material after the treatment in step (3) is transported to a granulation device for granulation, and then naturally cured for 1 to 3 days to obtain the organic-inorganic composite solidified granular humic filler.

2. The method for producing an organic-inorganic composite solidified granular humic filler according to claim 1, characterized in that: The mass percentages of the undersize humus soil, fly ash, slaked lime or carbide slag are 75% to 90%, 5% to 20% and 5% to 10% respectively.

3. The method for producing an organic-inorganic composite solidified granular humic filler according to claim 1 or 2, characterized in that: The mass concentration of the diluted organic binder solution is 1% to 5%.

4. The method for producing an organic-inorganic composite solidified granular humic filler according to claim 1 or 2, characterized in that: The composite solidified granular humic filler is spherical particles with a particle size of 1 mm to 10 mm.

5. The method for producing an organic-inorganic composite solidified granular humic filler according to claim 1 or 2, characterized in that: The pore size of the drum sieve of the under-sieve humus soil is 30 mm to 50 mm.

6. An organic-inorganic composite solidified granular humic filler, characterized by: The filler is prepared according to the production method of the organic-inorganic composite solidified granular humic filler according to any one of claims 1 to 5.

7. The use of the organic-inorganic composite solidified granular humic filler according to claim 6, characterized in that: The organic-inorganic composite solidified granular humic filler can be used in sewage treatment and odor treatment processes of biological fillers.