Method for preparing granular carrier using steel slag and electrolytic manganese residue and application thereof

Abstract

The present application is suitable for the field of anaerobic ammonia oxidation denitrification technology, and provides a method for preparing a granular carrier by using steel slag and electrolytic manganese slag, comprising the following steps: cleaning blocky steel slag and electrolytic manganese slag with a decontaminant, drying, mixing according to a certain proportion, grinding into powder by using a ball mill, and sieving to obtain powder A; weighing 5-10g of the powder A, adding an appropriate amount of oxalic acid to soak and placing for a period of time; then making into small balls, placing in a blast drying oven for air drying for 2h to obtain spherical particles; placing the above particles in a tube furnace or a muffle furnace, and going through a preheating, sintering and cooling process to obtain the granular carrier material. The application also provides the application of the spherical granular carrier material prepared by the method in denitrification in an anaerobic ammonia oxidation system. The granular carrier prepared by the present application fully utilizes the synergistic effect of Fe and Mn, improves the performance of microorganisms in utilizing the same, and simultaneously strengthens the high-efficiency low-carbon denitrification effect of the Anammox process.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of anaerobic ammonia oxidation denitrification, and particularly relates to a method for preparing a granular carrier by using steel slag and electrolytic manganese slag and application, which utilizes common industrial solid waste electrolytic manganese slag and steel slag to prepare a granular carrier and applies it to anaerobic ammonia oxidation denitrification, thereby significantly improving the denitrification effect. BACKGROUND

[0002] Water pollution caused by excessive input of nutrients is a serious problem worldwide. Nitrogen (N) compounds, such as compounds that produce ammonium (NH4 + ) and nitrate (NO3 - ) ions, are the most common water pollutants. Given that the nitrification process employed by wastewater treatment plants (WWTPs) can effectively remove NH4 + -N, NO3 - -N is the main form of N in the effluent of WWTPs, which usually contains a high concentration of total N (TN). Elevated concentrations of NO3 - -N can harm aquatic ecosystems and pose a risk to aquatic organisms and human health. Therefore, further treatment of the effluent of WWTPs is required.

[0003] Anaerobic ammonia oxidation (Anammox) technology refers to the process in which microorganisms convert ammonia to nitrogen gas using nitrite as an electron acceptor in an anaerobic or anoxic environment, as shown in formula (1) below. Compared to traditional denitrification technologies, Anammox has the advantages of short reaction process, low oxygen demand, low operating cost, no need for organic carbon source, low greenhouse gas emissions, and low sludge production. If it can be widely applied to municipal wastewater with larger nitrogen pollution emissions, it will have important significance for energy saving and consumption reduction of the water treatment industry and improvement of urban water environment. How to strengthen the growth and metabolism of Anammox bacteria, improve the denitrification efficiency, and ensure the long-term stable operation of the process are the current research hotspots of Anammox technology.

[0004] NH4 + + 1.32 NO2 - + 0.066 HCO3 - + 0.13 H + → 1.02 N2 + 0.26 NO3 - + 0.066 CH2O 0.5 N0.15 + 2.03 H2 (1)

[0005] Metal-enhanced Anammox is an economical and practical measure that can optimize the growth and metabolism of Anammox bacteria, enhance the abiotic denitrification reaction, and improve the denitrification efficiency of the system. Among them, manganese oxides are used as oxidizing agents to change or create new oxidation pathways in the nitrogen cycle. By utilizing manganese oxides as NH4 +In the anaerobic nitrification process, manganese can act as an electron acceptor to generate NO3 - , which is then reduced to N2 through biologically mediated denitrification or chemical denitrification (as shown in formulas (2)-(3)). However, when promoting this project, the long-term cost of continuously adding chemical reagents is high, and the source of manganese needs to be further optimized. Therefore, it is necessary to develop a lower-cost alternative.

[0006] 8MnO2+2NH4 + +12H + →8Mn 2+ +2NO3 - +10H2O (2)

[0007] 5Mn 2+ +2NO3 - +4H2O→5MnO2+N2+8H + (3)

[0008] Electrolytic manganese slag is the acid leaching waste slag produced by the reaction of manganese ore and sulfuric acid during the electrolytic manganese production process. Due to the continuous decline in the grade of manganese ore in recent years, the output of electrolytic manganese slag per ton of metallic manganese has also increased year by year, and it contains a large amount of soluble salts, such as water-soluble manganese, ammonia nitrogen, etc., which greatly affects the application of electrolytic manganese slag. Steel slag refers to the solid waste produced in the steelmaking process. Every ton of steel produced will also produce 270 to 300 kg of steel slag. Due to the presence of highly alkaline industrial residues, this seriously hinders the application of steel slag. The main chemical components of steel slag are CaO, SiO2, Al2O3, MgO, Fe2O3, etc. The steel slag and electrolytic manganese slag are mixed and ground. During the grinding process, due to CaO and alkaline conditions, the electrolytic manganese slag will undergo a fixed inclusion effect on Mn 2+ The ions are contained and fixed, as shown in formulas (4)-(5). In addition, the presence of CaO will cause the ambient temperature to rise during the grinding process, accelerating the conversion of ammonium salts to free state and releasing them in the form of ammonia gas, as shown in formulas (6)-(7). The presence of Fe will also enhance the high-efficiency and low-carbon denitrification effect of the Anammox process.

[0009] MnSO4+H2O+CaO→Mn(OH)2+CaSO4 (4)

[0010] Mn(OH)2+CO2+H2O→MnCO3+2H2O (5)

[0011] NH4++OH - →NH3(free state)+H2O (6)

[0012] NH3(free state)+Q(heat energy)→NH3(gaseous state) (7)

[0013] Based on the above research results, the application proposes a carrier prepared by mixing and grinding steel slag and electrolytic manganese slag in a certain proportion, which fully utilizes the synergistic effect of Fe and Mn, improves the performance of microorganisms in utilizing the carrier, and at the same time, strengthens the high-efficiency low-carbon denitrification effect of the Anammox process, to overcome the shortcomings in current practical applications. SUMMARY

[0014] The purpose of the embodiment of the application is to provide a method and application for preparing a granular carrier from steel slag and electrolytic manganese slag, which selects economic and easily available steel slag and electrolytic manganese slag as raw materials, mixes and grinds them in a certain proportion, and sintering into a carrier, which fully utilizes the synergistic effect of Fe and Mn, improves the performance of microorganisms in utilizing the carrier, and at the same time, strengthens the high-efficiency low-carbon denitrification effect of the Anammox process.

[0015] The embodiment of the application is implemented in the following way: a method for preparing a granular carrier from steel slag and electrolytic manganese slag, comprising the following steps:

[0016] Step 1: Clean the blocky steel slag and electrolytic manganese slag with a decontaminant, dry them, mix them in a certain proportion, grind them into powder using a ball mill, and sieve them to obtain powder A;

[0017] Step 2: Weigh 5-10g of powder A, add an appropriate amount of oxalic acid to soak and place for a period of time; then make small balls, place them in a forced air drying oven for 2h to obtain spherical particles;

[0018] Step 3: Place the above particles in a tube furnace or muffle furnace, go through the processes of preheating, sintering and cooling, and obtain the granular carrier material.

[0019] In step 1, the mass percentage of powder steel slag in the obtained powder A is 40%-60%, and the mass percentage of electrolytic manganese slag is 40%-60%.

[0020] In step 1, the mesh size of the sieve is 80-200 mesh.

[0021] In step 2, the concentration of the oxalic acid solution is 0.01-0.05mol / L, the solid-liquid ratio of powder A to the oxalic acid solution is 4-5:1kg / L, and the diameter of the prepared small balls is 3mm-5mm.

[0022] In step 3, the preheating temperature is 200-400℃, and the preheating time is 30min-60min; the sintering temperature is 700-900℃, and the sintering time is 10min-30min.

[0023] Another purpose of the embodiment of the present application is the application of the spherical granular carrier material prepared by the method of preparing granular carrier using steel slag and electrolytic manganese slag in the denitrification of an anaerobic ammonia oxidation system.

[0024] Further technical solutions, the application comprises the following steps:

[0025] Two anaerobic SBR reactors are set up, which are a control group and an experimental group respectively; the reactor of the control group is provided with a stirring device, a temperature control device and a water inlet peristaltic pump, the temperature is set, the drainage ratio is controlled, the water inlet mode adopts one-time water inlet, and the SBR is operated according to the operation mode of one-time water inlet, stirring, drainage and idling during the reaction period; the sewage hydraulic retention time is designed to arrange the starting time of each stage and is controlled through a time control switch; the experimental group is provided with a certain mass of granular carrier material added into the reactor, and the remaining steps are the same as those of the control group.

[0026] Further technical solutions, the reactor is made of organic glass, and the effective volume is 3L; tin paper is further covered outside the reactor, and the reactor is further provided with an aeration device for meeting the oxygen demand of the nitrification reaction and the air inlet amount of which can be adjusted, and the air inlet amount is 0.2-0.8L / min.

[0027] Further technical solutions, the set temperature is 35℃±1℃; the drainage ratio is 30%-80%; the stirring rate is 50-120r / min; and the sewage hydraulic retention time is 11.5h.

[0028] Further technical solutions, the concentration of the granular carrier material added into the reactor of the experimental group is 1g / L.

[0029] The method for preparing granular carrier using steel slag and electrolytic manganese slag and the application provided by the embodiment of the present application have the following beneficial effects:

[0030] 1) The electrolytic manganese slag and the steel slag are used as the carrier to realize the idea of turning waste into treasure and treating waste with waste, which not only reduces the negative impact of waste on the environment, but also brings multiple positive effects such as resource recycling, denitrification efficiency improvement and economic benefits, and this sustainable waste management method has important environmental and economic significance;

[0031] 2) The prepared granular carrier will not only affect the anaerobic ammonia oxidation activity in the anaerobic ammonia oxidation process, thereby affecting the nitrogen removal efficiency and start-up to different extents, but also significantly change the abundance of microbial communities by changing their concentration, thereby affecting the overall performance of the reaction process;

[0032] 3) The manganese oxides in the prepared spherical composite carrier are used as oxidants to change or create new oxidation pathways in the nitrogen cycle process, and cooperate with iron oxides to be added to the anaerobic ammonia oxidation system, which not only helps to maintain an anaerobic environment suitable for the growth of Anammox bacteria, but also reduces the production of nitrate, further improving the nitrogen removal rate. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The designed anaerobic SBR reactor;

[0034] Figure 2 The XRD pattern of the prepared granular carrier;

[0035] Figure 3 The effect diagram of the granular carrier applied to sludge anaerobic ammonia oxidation denitrification.

[0036] In the figure: 1-overflow port, 2-water inlet, 3-sampling port one, 4-sampling port two, 5-sampling port three, 6-sampling port four, 7-sampling port five, 8-water bath inlet, 9-water bath outlet, 10-water inlet tank, 11-water inlet pump, 12-constant temperature water bath, 13-water bath layer, 14-stirrer, 15-water outlet pump, 16-water outlet tank, 17-aeration disc, 18-air flowmeter, 19-air pump. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0038] The specific implementation of the present application is described in detail below in combination with specific examples.

[0039] Example 1

[0040] One embodiment of the present application provides a method for preparing a granular carrier using steel slag and electrolytic manganese slag, comprising the following steps:

[0041] Step 1, wash the blocky steel slag and electrolytic manganese slag with a decontaminant, dry them, mix them according to a certain proportion, grind them into powder using a ball mill, and sieve them to obtain powder A;

[0042] Step 2, weigh 5g of powder A, add an appropriate amount of oxalic acid to soak and place for a period of time; then make small balls, place them in a forced air drying oven for 2h to obtain spherical particles;

[0043] Step 3, place the above particles in a tube furnace or a muffle furnace, go through a preheating, sintering and cooling process to obtain the granular carrier material.

[0044] In step 1, the mass percentage of the powder steel slag and the electrolytic manganese slag in the obtained powder A is 40% and 60% respectively, and the dry weight components in the mixed sample satisfy the following formula:

[0045]

[0046] In step 1, the screening mesh number of the screened powder is 80 meshes.

[0047] In step 2, the concentration of the oxalic acid solution is 0.01 mol / L, and the solid-liquid ratio of the powder A and the oxalic acid solution is 4:1 kg / L.

[0048] In step 2, the diameter of the prepared small balls is 3 mm.

[0049] In step 3, the preheating temperature is 200 DEG C, the preheating time is 30 min, the sintering temperature is 700 DEG C, and the sintering time is 10 min.

[0050] Example 2

[0051] An embodiment of the present application provides a method for preparing a granular carrier by using steel slag and electrolytic manganese slag, comprising the following steps:

[0052] In step 1, the blocky steel slag and the electrolytic manganese slag are cleaned by using a decontaminant, dried, mixed according to a certain proportion, ground into powder by using a ball mill, screened, and powder A is obtained;

[0053] In step 2, 10 g of the powder A is weighed, soaked by adding an appropriate amount of oxalic acid and placed for a period of time, then small balls are prepared, placed in a blast drying oven for air drying for 2 h, and spherical particles are obtained.

[0054] In step 3, the particles are placed in a tube furnace or a muffle furnace, and the particles are obtained by preheating, sintering and cooling.

[0055] In step 1, the mass percentage of the powder steel slag and the electrolytic manganese slag in the obtained powder A is 60% and 40% respectively, and the dry weight components in the mixed sample satisfy the following formula:

[0056]

[0057] In step 1, the screening mesh number of the screened powder is 200 meshes.

[0058] In step 2, the concentration of the oxalic acid solution is 0.05 mol / L, and the solid-liquid ratio of the powder A and the oxalic acid solution is 5:1 kg / L.

[0059] In step 2, the diameter of the prepared small balls is 5 mm.

[0060] In step 3, the preheating temperature is 400° C. and the preheating time is 60 min; the sintering temperature is 900° C. and the sintering time is 30 min.

[0061] Example 3

[0062] An embodiment of the present invention provides a method for preparing a particle carrier using steel slag and electrolytic manganese slag, comprising the following steps:

[0063] Step 1: Clean the bulk steel slag and electrolytic manganese slag with a detergent, dry them, mix them in a certain proportion, grind them into powder using a ball mill, and sieve them to obtain powder A;

[0064] Step 2: Weigh 7.5 g of powder A, add an appropriate amount of oxalic acid to soak it and let it stand for a while; then make small balls, place them in a forced air drying oven and air dry them for 2 hours to obtain spherical particles;

[0065] Step 3: Place the above particles in a tube furnace or a muffle furnace, and undergo preheating, sintering and cooling processes to obtain the particle carrier material.

[0066] In step 1, the mass percentages of powdered steel slag and electrolytic manganese slag in the obtained powder A are 50% and 50% respectively, and the dry weight components in the mixed sample satisfy the following formula:

[0067]

[0068] In step 1, the sieve is 140 mesh.

[0069] In step 2, the concentration of the oxalic acid solution is 0.03 mol / L, and the solid-liquid ratio of powder A to the oxalic acid solution is 4.5:1 kg / L.

[0070] In step 2, the prepared pellets have a diameter of 4 mm.

[0071] In step 3, the preheating temperature is 300° C. and the preheating time is 45 minutes; the sintering temperature is 800° C. and the sintering time is 20 minutes.

[0072] like Figures 1-3 As shown, one embodiment of the present invention further provides the use of a spherical granular carrier material prepared by a method for preparing a granular carrier using steel slag and electrolytic manganese slag in denitrification in an anaerobic ammonium oxidation system, comprising the following steps:

[0073] Two anaerobic SBR reactors are set, which are control group and experimental group respectively; the reactor of the control group is provided with stirring device, temperature control device and water inlet peristaltic pump, a certain temperature is set, a certain drainage ratio is controlled, water is added in one time, SBR is operated according to the operation mode of water addition in one time, stirring, drainage and idling during the reaction period; the sewage is kept for a certain time, so that the starting time of each stage is arranged and is controlled through time control switch; the experimental group is provided with a certain mass of granular carrier material in the reactor, and the remaining steps are the same as those of the control group. Figure 3 As shown in the effect drawing,

[0074] The reactor is made of organic glass, and the effective volume is 3L; in order to avoid the inhibition of light on the denitrification effect of anaerobic ammonia oxidation bacteria, the reactor is covered with tin paper, which can play the roles of heat preservation and light shielding; in order to ensure the anaerobic ammonia oxidation reaction, the reactor is provided with an aeration device, the air inlet is adjusted, the air inlet is 0.2-0.8L / min, preferably 0.5L / min, and a small amount of oxygen is used to meet the partial nitrification reaction.

[0075] The stirring rate is 50-120r / min, preferably 80r / min; a certain temperature is set to 35℃±1℃; the drainage ratio is 30%-80%, preferably 50%; the sewage is kept for a certain time, which is 11.5h; the experimental group is provided with a certain mass of granular carrier material in the reactor, and the concentration of the certain mass of granular carrier material is 1g / L.

[0076] It should be noted that the anaerobic SBR reactor can adopt the mode as shown in Figure 1 When the mode as shown in Figure 1 is adopted, a water bath layer 13 is arranged on the side wall of the reactor, and a stirrer 14 is arranged for stirring the materials in the reactor; a water inlet pump 11 is used to convey the water in the water inlet tank 10 to the water inlet of the reactor; a constant temperature water bath pot 12 is arranged and connected with the water bath inlet 8 and water bath outlet 9 of the reactor; an aeration disc 17 is arranged at the bottom of the reactor; the sampling ports one 3, two 4, three 5, four 6 and five 7 are arranged from top to bottom on the reactor; the water outlet of the reactor is connected with the water outlet tank 16 through the water outlet pump 15; the top of the reactor is provided with an overflow port 1; the bottom of the reactor is connected with an air pump 19, and an air flow meter 18 is arranged for monitoring.

[0077] The above embodiment of the present application provides a method for preparing granular carrier by using steel slag and electrolytic manganese slag and application, and the main advantages are as follows:

[0078] 1) The application of electrolytic manganese residue and steel slag as carriers realizes the idea of turning waste into treasure and treating waste with waste, which not only reduces the negative impact of waste on the environment, but also brings multiple positive effects such as resource recycling, nitrogen removal efficiency improvement and economic benefits. This sustainable waste management method has important environmental and economic significance;

[0079] 2) The prepared granular carriers not only affect the activity of anaerobic ammonia oxidation in the process of anaerobic ammonia oxidation, thereby affecting the nitrogen removal efficiency and start-up to different extents, but also significantly change the abundance of microbial communities by changing their concentrations, thereby affecting the overall performance of the reaction process;

[0080] 3) The manganese oxide in the prepared spherical composite carrier is used as an oxidizing agent to change or create new oxidation pathways during the nitrogen cycle, and cooperates with iron oxide to be added to the anaerobic ammonia oxidation system, which not only helps to maintain an anaerobic environment suitable for the growth of Anammox bacteria, but also reduces the production of nitrate and further improves the nitrogen removal rate.

[0081] Each technical feature of the above-described embodiments can be combined arbitrarily, and to make the description concise, each technical feature in the above-described embodiments is not described in all possible combinations, however, as long as the combination of these technical features does not exist contradictory, it should be considered as the scope of the present disclosure.

[0082] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the present patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present patent should be subject to the appended claims.

Claims

1. A method for preparing granular carriers using steel slag and electrolytic manganese slag, characterized by, The method comprises the following steps: Step 1, the blocky steel slag and electrolytic manganese residue are cleaned with a decontaminant, dried, mixed according to a certain proportion, ground into powder by using a ball mill, and sieved to obtain powder A; Step 2, 5-10 g of the powder A is weighed, soaked with an appropriate amount of oxalic acid and placed for a period of time; then small balls are prepared and placed in a blast drying oven for air drying for 2 h to obtain spherical particles; Step 3, the particles are placed in a tube furnace or a muffle furnace to undergo a preheating, sintering and cooling process to obtain the particle carrier material.

2. The method of preparing granular carriers using steel slag and electrolytic manganese residue according to claim 1, characterized in that, In step 1, the mass percentage of the powder steel slag in the obtained powder A is 40%-60%, and the mass percentage of the electrolytic manganese residue is 40%-60%.

3. The method of preparing granular carriers using steel slag and electrolytic manganese slag according to claim 1 or 2, characterized in that, In step 1, the mesh size of the sieving is 80-200 mesh.

4. The method of preparing granular carriers using steel slag and electrolytic manganese slag according to claim 1, characterized by, In step 2, the concentration of the oxalic acid solution is 0.01-0.05 mol / L, and the solid-liquid ratio of the powder A to the oxalic acid solution is 4-5:1 kg / L; The diameter of the prepared small balls is 3 mm-5 mm.

5. The method of preparing granular carriers using steel slag and electrolytic manganese slag according to claim 1, characterized by, In step 3, the preheating temperature is 200-400 DEG C, and the preheating time is 30 min-60 min; The sintering temperature is 700-900 DEG C, and the sintering time is 10 min-30 min.

6. The application of the spherical particle carrier material prepared by the method of claim 1-5 in the denitrification of an anaerobic ammonia oxidation system.

7. Use according to claim 6, characterized in that, The method comprises the following steps: Two anaerobic SBR reactors are set up, which are a control group and an experimental group; The reactor of the control group is provided with a stirring device, a temperature control device and a water inlet peristaltic pump, the temperature is set, the drainage ratio is controlled, the water inlet mode adopts one-time water inlet, and the SBR is operated according to the operation mode of one-time water inlet, stirring, drainage and idling during the reaction period; The hydraulic retention time of the sewage is designed to arrange the starting time of each stage and is controlled through a time control switch; The experimental group adds a certain mass of the particle carrier material into the reactor, and the remaining steps are the same as those of the control group.

8. Use according to claim 7, characterized in that, The reactor is made of organic glass and has an effective volume of 3 L; The reactor is also covered with tin paper, and the reactor is also provided with an aeration device for meeting the oxygen demand of the nitrification reaction and the air inlet amount of which can be adjusted, and the air inlet amount is 0.2-0.8 L / min.

9. Use according to claim 7, characterized in that, The set temperature is 35 DEG C ± 1 DEG C; The drainage ratio is 30%-80%; The stirring rate is 50-120 r / min; The hydraulic retention time of the sewage is 11.5 h.

10. Use according to claim 7, characterized in that, The concentration of the particle carrier material added into the reactor of the experimental group is 1 g / L.

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