Manganese autotrophic denitrification biological filter material as well as autoclaved foaming preparation method and application thereof

Abstract

The invention belongs to the technical field of advanced treatment of wetland sewage, and discloses a manganese autotrophic denitrification biological filter material as well as an autoclaved foaming preparation method and application thereof, and the application of the manganese autotrophic denitrification biological filter material is mainly used for nitrogen removal by denitrification of manganese autotrophic microorganisms in constructed wetlands, and the manganese autotrophic denitrification biological filter material has the advantages that the nitrogen removal efficiency is improved; particularly, a low-temperature denitrification nitrogen removal process in autumn and winter low-temperature seasons in northern China; according to the preparation method of the manganese autotrophic denitrification biological filter material, a certain proportion of manganese element is added, and a slow-controlled-release manganese source is provided for manganese autotrophic denitrification microorganisms; according to the preparation method of the manganese autotrophic denitrification biological filter material, after the ground manganese powder is subjected to acid activation, the added manganese sand can be better fully mixed with other components in a steam-cured concrete premix, the overall strength of a building block is not influenced, the building block is not easy to crush in the long-term use process, and the actual service life of the filter material is prolonged.

Description

Technical Field

[0001] This invention belongs to the field of advanced wetland wastewater treatment technology, specifically a manganese autotrophic denitrification biological filter media, its autoclaving foaming preparation method, and its application. Background Technology

[0002] With the increasing volume of wastewater discharge, increasingly stringent requirements have been placed on the content of ammonia nitrogen and total nitrogen. Constructed wetlands, as an important method for the advanced treatment of total nitrogen in water bodies, especially for the upgrading and renovation of centralized wastewater treatment plants, are increasingly widely used. In northern my country, where temperature variations are significant throughout the four seasons, autotrophic denitrification filter media, particularly sulfur-autotrophic denitrification filter media, are gaining popularity. However, sulfur-autotrophic denitrification is only suitable for constructed wetland environments within a certain temperature range (generally requiring water temperatures above 25℃). At low temperatures, it is difficult to guarantee the long-term stability of the biochemical treatment effect; furthermore, the process easily generates hydrogen sulfide, and there is also the problem of excessively high sulfate levels in the effluent. Manganese-autotrophic microorganisms, using Mn... 2+ As an electron donor for denitrification, it exhibits good removal effects of ammonia nitrogen and total nitrogen under low-temperature conditions (Zheng Shengchen, Manganese autotrophic denitrifying bacteria remove nitrate (total nitrogen) and Mn from groundwater). 2+ Experimental research, Master's thesis, Xi'an University of Architecture and Technology, 2016.

[0003] Patent CN102775116 B discloses a method for preparing autoclaved bricks using electrolytic manganese dioxide waste residue. While this method involves manganese dioxide waste residue and autoclaved concrete technology, it primarily aims to reuse manganese dioxide refining waste residue to produce aerated concrete building materials. It also addresses the environmental problems caused by electrolytic manganese dioxide waste residue, turning waste into treasure and possessing certain economic value. However, the final product has a very low manganese content (electrolytic manganese dioxide waste residue is acid leaching and pressure filter residue produced during the electrolytic manganese dioxide production process; its chemical composition is complex, containing not only SiO2, Al2O3, and Fe2O3, but also fluorides and metallic components such as Cd, Cu, Ni, and Pb). Direct application to wastewater treatment could potentially cause further pollution. Furthermore, the product does not involve the denitrification utilization of manganese autotrophic microorganisms, resulting in a significant difference in its focus and practical application.

[0004] CN115806326A discloses a filter media for enhanced nitrogen and phosphorus removal in wastewater treatment. This filter media comprises a composition A consisting of silicate cement, a foaming agent, and a foam stabilizer, and a composition B consisting of bentonite, pyrite, sulfur, zeolite, biochar, and fine sand. Each component is treated individually, and then the mixture is molded to obtain a highly efficient nitrogen and phosphorus removal material. This filter media incorporates autoclaved aerated concrete technology. By adding bentonite and sulfur-containing components to component B and mixing it with component A before foaming, it can provide functional components for sulfur-autotrophic microorganisms and a suitable habitat for them. However, this method results in a short service life for the sulfur-autotrophic filter media, requires a high suitable denitrification temperature range (above 25℃), is not well-suited for the low-temperature winter environments of northern regions, and is prone to generating secondary pollution problems such as hydrogen sulfide and sulfates.

[0005] Based on this, a manganese autotrophic denitrification biological filter media was designed, along with its steam pressure foaming preparation method and application. Summary of the Invention

[0006] In view of the above situation and to overcome the defects of the prior art, the present invention provides a manganese autotrophic denitrification biological filter material, its preparation method by autoclaving and foaming, and its application, which effectively solves the problems raised in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing manganese autotrophic denitrification biological filter media by autoclaving foaming, comprising the following preparation steps: S1. First, add a certain amount of warm water to the mixing tank, and then add a certain amount of ground fly ash from the power plant, accounting for 65-70% of the total amount, to make a fly ash slurry of a certain consistency. S2. While stirring, continuously add warm water, and simultaneously add measured amounts of gypsum, lime, and cement to the fly ash slurry in sequence; wherein, gypsum accounts for 3-5% of the total amount, lime accounts for 15-25% of the total amount, and cement accounts for 8-15% of the total amount; S3. Add 0.5% aluminum powder or aluminum powder paste and stir for 30 seconds; S4. Prepare a mixture of hydrochloric acid and citric acid with a certain acidity, and soak the commercially available manganese powder for about 1 hour to activate the manganese dioxide component. S5. Under stirring conditions, add the activated manganese sand to the slurry prepared in step S1; S6. Maintain the slurry temperature at 40℃; S6. After pouring the above slurry into a certain mold, let it stand still to promote foaming and initial setting; the temperature is controlled at 55-60℃ and the standing time is 1-3 hours. S7. After curing, cut the initial set concrete blocks to a certain extent according to subsequent requirements; use steel wire to cut the initial set blocks into squares of a certain size. S8. Perform autoclaving in an autoclave at a temperature of 160–190℃ for 6–10 hours. S10, discharge, crush and ready for use.

[0008] A manganese autotrophic denitrification biological filter media is a porous manganese autotrophic microbial denitrification biological filter media prepared by the method for preparing denitrification biological filter media according to claim 1.

[0009] The application of manganese autotrophic denitrification biological filter media is mainly used for denitrification and nitrogen removal by manganese autotrophic microorganisms in constructed wetlands, especially for low-temperature denitrification and nitrogen removal processes during the autumn and winter seasons in northern my country.

[0010] Compared with the prior art, the beneficial effects of the present invention are: 1. The preparation method of the manganese autotrophic denitrifying biological filter material of the present invention, wherein a certain proportion of manganese element (manganese dioxide) is added to provide a slow-release manganese source for manganese autotrophic denitrifying microorganisms; 2. The preparation method of the manganese autotrophic denitrification biological filter material of the present invention involves acid-activating ground manganese powder (manganese sand). The added manganese sand can not only be better mixed with other components in the steam-cured concrete premix, but also does not affect the overall strength of the block. It is not easy to be crushed during long-term use, thus increasing the actual service life of the filter material. 3. The preparation method of the manganese autotrophic denitrification biological filter material of the present invention involves embedding manganese elements in an autoclaved concrete skeleton. During use, the manganese elements have a slow-release effect and can serve as a manganese source for manganese autotrophic microorganisms for a long time. It also reduces the manganese content in wastewater and will not cause secondary pollution to water bodies. The final products of denitrification and manganese elements in the manganese autotrophic microbial filter material are high-valence oxides of N2 and Mn (low toxicity), and it avoids the problems of malodor and sulfate exceeding the standard that are easily generated by sulfur autotrophic denitrification microorganisms.

[0011] 4. The manganese autotrophic denitrification biological filter media prepared by the method of the present invention, with porous autoclaved concrete as the attachment carrier, can greatly increase the amount of manganese autotrophic microorganisms attached, thereby increasing the denitrification efficiency. Attached Figure Description

[0012] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0013] In the attached diagram: Figure 1 Image of manganese autotrophic porous denitrification biological filter media; Figure 2 SEM image of manganese sand in manganese autotrophic porous denitrification biological filter media. Detailed Implementation

[0014] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0015] Depend on Figure 1 This invention relates to a method for preparing manganese autotrophic denitrification biological filter media by autoclaving foaming, comprising the following preparation steps: S1. First, add a certain amount of warm water to the mixing tank, and then add a certain amount of ground fly ash from the power plant, accounting for 65-70% of the total amount, to make a fly ash slurry of a certain consistency. S2. While stirring, continuously add warm water, and simultaneously add measured amounts of gypsum, lime, and cement to the fly ash slurry in sequence; wherein, gypsum accounts for 3-5% of the total amount, lime accounts for 15-25% of the total amount, and cement accounts for 8-15% of the total amount; S3. Add 0.5% aluminum powder or aluminum powder paste and stir for 30 seconds; S4. Prepare a mixture of hydrochloric acid and citric acid with a certain acidity, and soak the commercially available manganese powder for about 1 hour to activate the manganese dioxide component. S5. Under stirring conditions, add the activated manganese sand to the slurry prepared in step S1; S6. Maintain the slurry temperature at 40℃; S6. After pouring the above slurry into a certain mold, let it stand still to promote foaming and initial setting; the temperature is controlled at 55-60℃ and the standing time is 1-3 hours. S7. After curing, cut the initial set concrete blocks to a certain extent according to subsequent requirements; use steel wire to cut the initial set blocks into squares of a certain size. S8. Perform autoclaving in an autoclave at a temperature of 160–190℃ for 6–10 hours. S10, discharge, crush and ready for use.

[0016] A manganese autotrophic denitrification biological filter media is a porous manganese autotrophic microbial denitrification biological filter media prepared by the method for preparing denitrification biological filter media according to claim 1.

[0017] The application of manganese autotrophic denitrification biological filter media is mainly used for denitrification and nitrogen removal by manganese autotrophic microorganisms in constructed wetlands, especially for low-temperature denitrification and nitrogen removal processes during the autumn and winter seasons in northern my country.

[0018] Example 1: A method for preparing manganese autotrophic denitrification biological filter media by autoclaving foaming includes the following preparation steps: S1. First, add a certain amount of warm water to the mixing tank, and then add a certain amount of ground fly ash from the power plant, accounting for 65% of the total amount, to make a fly ash slurry of a certain consistency. S2. While stirring, continuously add warm water, and simultaneously add measured amounts of gypsum, lime, and cement to the fly ash slurry in the following order: gypsum accounts for 3% of the total amount, lime accounts for 22% of the total amount, and cement accounts for 10% of the total amount. S3. Add 0.5% aluminum powder or aluminum powder paste and stir for 30 seconds; S4. Prepare a mixture of hydrochloric acid and citric acid with a certain acidity, and soak the commercially available manganese powder for about 1 hour to activate the manganese dioxide component. S5. Under stirring conditions, add the activated manganese sand to the slurry prepared in step S1; S6. Maintain the slurry temperature at 40℃; S6. After pouring the above slurry into a certain mold, let it stand still to promote foaming and initial setting; the temperature is controlled at 55℃ and the standing time is 2 hours. S7. After curing, cut the initial set concrete blocks to a certain extent according to subsequent requirements; use steel wire to cut the initial set blocks into squares of a certain size. S8. Perform autoclaving in an autoclave at a temperature of 180℃ for 6 hours. S10, discharge, crush and ready for use.

[0019] A manganese autotrophic denitrification biological filter media is a porous manganese autotrophic microbial denitrification biological filter media prepared by the method for preparing denitrification biological filter media according to claim 1.

[0020] The application of manganese autotrophic denitrification biological filter media is mainly used for denitrification and nitrogen removal by manganese autotrophic microorganisms in constructed wetlands, especially for low-temperature denitrification and nitrogen removal processes during the autumn and winter seasons in northern my country.

[0021] Example 2: A method for preparing manganese autotrophic denitrification biological filter media by autoclaving foaming includes the following preparation steps: S1. First, add a certain amount of warm water to the mixing tank, and then add a certain amount of ground fly ash from the power plant, accounting for 65% of the total amount, to make a fly ash slurry of a certain consistency. S2. While stirring, continuously add warm water, and simultaneously add measured amounts of gypsum, lime, and cement to the fly ash slurry in the following order: gypsum accounts for 4% of the total amount, lime accounts for 19% of the total amount, and cement accounts for 12% of the total amount. S3. Add 0.5% aluminum powder or aluminum powder paste and stir for 30 seconds; S4. Prepare a mixture of hydrochloric acid and citric acid with a certain acidity, and soak the commercially available manganese powder for about 1 hour to activate the manganese dioxide component. S5. Under stirring conditions, add the activated manganese sand to the slurry prepared in step S1; S6. Maintain the slurry temperature at 40℃; S6. After pouring the above slurry into a certain mold, let it stand still to promote foaming and initial setting; the temperature is controlled at 60℃ and the standing time is 1.5 hours. S7. After curing, cut the initial set concrete blocks to a certain extent according to subsequent requirements; use steel wire to cut the initial set blocks into squares of a certain size. S8. Perform autoclaving in an autoclave at a temperature of 170℃ for 8 hours. S10, discharge, crush and ready for use.

[0022] A manganese autotrophic denitrification biological filter media is a porous manganese autotrophic microbial denitrification biological filter media prepared by the method for preparing denitrification biological filter media according to claim 1.

[0023] The application of manganese autotrophic denitrification biological filter media is mainly used for denitrification and nitrogen removal by manganese autotrophic microorganisms in constructed wetlands, especially for low-temperature denitrification and nitrogen removal processes during the autumn and winter seasons in northern my country.

[0024] Example 3: A method for preparing manganese autotrophic denitrification biological filter media by autoclaving foaming includes the following preparation steps: S1. First, add a certain amount of warm water to the mixing tank, and then add a certain amount of ground fly ash from the power plant, accounting for 70% of the total amount, to make a fly ash slurry of a certain consistency. S2. While stirring, continuously add warm water, and simultaneously add measured amounts of gypsum, lime, and cement to the fly ash slurry in the following order: gypsum accounts for 3% of the total amount, lime accounts for 17% of the total amount, and cement accounts for 10% of the total amount. S3. Add 0.5% aluminum powder or aluminum powder paste and stir for 30 seconds; S4. Prepare a mixture of hydrochloric acid and citric acid with a certain acidity, and soak the commercially available manganese powder for about 1 hour to activate the manganese dioxide component. S5. Under stirring conditions, add the activated manganese sand to the slurry prepared in step S1; S6. Maintain the slurry temperature at 40℃; S6. After pouring the above slurry into a certain mold, let it stand still to promote foaming and initial setting; the temperature is controlled at 60℃ and the standing time is 1.5 hours. S7. After curing, cut the initial set concrete blocks to a certain extent according to subsequent requirements; use steel wire to cut the initial set blocks into squares of a certain size. S8. Perform autoclaving in an autoclave at a temperature of 175℃ for 8 hours. S10, discharge, crush and ready for use.

[0025] A manganese autotrophic denitrification biological filter media is a porous manganese autotrophic microbial denitrification biological filter media prepared by the method for preparing denitrification biological filter media according to claim 1.

[0026] The application of manganese autotrophic denitrification biological filter media is mainly used for denitrification and nitrogen removal by manganese autotrophic microorganisms in constructed wetlands, especially for low-temperature denitrification and nitrogen removal processes during the autumn and winter seasons in northern my country.

[0027] The manganese autotrophic denitrification biological filter media prepared in Examples 1-3 above were subjected to the following performance tests, including the following steps: The experimental setup and analytical methods were adopted according to the literature (Liu Feng et al., Study on Deep Nitrogen Removal of Secondary Effluent from Wastewater Treatment Plant by Carbon Source Enhanced Sulfur Autotrophic Denitrification, Journal of Safety and Environment, V23, No3, 864-873). Examples 1-3, as well as gravel and volcanic rock, were used as denitrifying microbial filter media. The same batch of anaerobic liquid from a wastewater treatment plant in Weifang City was inoculated, and the system was run continuously for 7 days to test the removal rate of nitrate nitrogen in the influent and effluent of the simulated wastewater. The test results are shown in the table below: Test calculation results

[0028] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0029] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing manganese autotrophic denitrification biological filter media by autoclaving and foaming, characterized in that: The preparation steps include the following: S1. First, add a certain amount of warm water to the mixing tank, and then add a certain amount of ground fly ash from the power plant, accounting for 65-70% of the total amount, to make a fly ash slurry of a certain consistency. S2. While stirring, continuously add warm water, and simultaneously add measured amounts of gypsum, lime, and cement to the fly ash slurry in sequence; wherein, gypsum accounts for 3-5% of the total amount, lime accounts for 15-25% of the total amount, and cement accounts for 8-15% of the total amount; S3. Add 0.5% aluminum powder or aluminum powder paste and stir for 30 seconds; S4. Prepare a mixture of hydrochloric acid and citric acid with a certain acidity, and soak the commercially available manganese powder for about 1 hour to activate the manganese dioxide component. S5. Under stirring conditions, add the activated manganese sand to the slurry prepared in step S1; S6. Maintain the slurry temperature at 40℃; S6. After pouring the above slurry into a certain mold, let it stand still to promote foaming and initial setting; the temperature is controlled at 55-60℃ and the standing time is 1-3 hours. S7. After curing, cut the initial set concrete blocks to a certain extent according to subsequent requirements; use steel wire to cut the initial set blocks into squares of a certain size. S8. Perform autoclaving in an autoclave at a temperature of 160–190℃ for 6–10 hours. S10, discharge, crush and ready for use.

2. A manganese autotrophic denitrification biological filter media, characterized in that: It is a porous manganese autotrophic microbial denitrification biological filter media prepared by the method of preparing denitrifying biological filter media according to claim 1.

3. An application of the manganese autotrophic denitrification biological filter media according to claim 2, characterized in that: It is mainly used for denitrification of manganese autotrophic microorganisms in constructed wetlands, especially for low-temperature denitrification processes during the autumn and winter seasons in northern my country.

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