Iron mud comprehensive recycling subsystem and method for industrial wastewater treatment, efficiency improvement and carbon reduction

Abstract

The invention discloses an iron mud comprehensive recycling subsystem and method for industrial wastewater treatment, efficiency improvement and carbon reduction, and belongs to the technical field of wastewater treatment. The iron sludge comprehensive recycling sub-system is independent of the wastewater treatment main system and comprises an iron sludge pulping tank, a rotational flow system, a resettling system and a reductive iron sludge tank which are connected in sequence. The recycling method comprises the following steps: pulping filtered Fenton wet mud, then carrying out deep washing, efficient concentration and crude separation, and strategically applying the separated muddy water or mud to key working sections of a wastewater treatment main system, including an anaerobic biochemical system, a flocculation floatation tank, an iron ammonia oxidation MBR tank and a Fenton oxidation system. According to the method, the removal efficiency of pollutants such as organic matters, total nitrogen and total phosphorus in each application section can be obviously improved, the energy consumption, material consumption and carbon emission of a wastewater treatment main system are effectively reduced, the operation cost is reduced, and dual benefits of environmental protection and economy are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment. Specifically, it relates to an iron sludge comprehensive recycling subsystem and method for enhancing the efficiency and reducing carbon in industrial wastewater treatment. Background Art

[0002] The petrochemical industry and fine chemical industries such as pesticides, pharmaceuticals, dyes, and new materials are the main sources of highly toxic and difficult-to-degrade organic wastewater. The organic wastewater treatment processes thereof mostly involve typical process technologies such as flocculation air flotation, micro-electrolysis (zero-valent iron reduction), Fenton oxidation, and anaerobic biochemistry. Among them, the Fenton oxidation process, on the one hand, uses hydroxyl radicals with a high redox potential generated by the Fenton reagent (H2O2 and ferrous salts) to oxidize and decompose difficult-to-degrade organic substances, and on the other hand, can adsorb and capture some organic substances through the floc precipitates generated by subsequent iron salt neutralization. Due to its many advantages such as simple process, less investment, wide treatment range, and large operation flexibility, it has become the most commonly used pretreatment technology for difficult-to-degrade organic wastewater at present.

[0003] However, a large amount of iron sludge is generated during the Fenton oxidation process, and this iron sludge generally belongs to hazardous waste, with high safety disposal costs, resulting in a relatively high operating cost of the Fenton process. Currently, the research on the recycling and utilization of Fenton iron sludge mostly adopts the method of medium-temperature pyrolysis or high-temperature roasting to convert it into flocculants, catalysts, or adsorbents for reuse. For example, Patent 202211682504.7 uses activated sludge and Fenton iron sludge to prepare a carbon-based ozone catalyst by pyrolysis at 450-900°C; Patent 202410214050.3 uses Fenton iron sludge and polymer fibers to prepare an iron-based carrier catalyst filler by high-temperature self-reduction carbonization at 1100-120°C. After investigating many actual operation cases of the Fenton process, it is found that the Fenton iron sludge is generally directly transported out for disposal after being discharged from the wastewater treatment system, and rarely considered for reuse in the original Fenton section or other sections of the wastewater treatment system, resulting in a relatively low comprehensive benefit created by the Fenton iron sludge. Summary of the Invention

[0004] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further elaborated in the Detailed Description of the Invention section. The Summary of the Invention section of the present invention does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0005] In the context of the great era of energy conservation, carbon reduction, quality improvement and efficiency enhancement, improving the efficiency and effectiveness of industrial wastewater treatment systems is of great significance for strengthening the sustainable development capabilities of enterprises and promoting the green transformation of the social economy. This invention focuses on the problems of low reuse rate and low comprehensive benefits of Fenton iron sludge in wastewater treatment systems, and creatively proposes an iron sludge comprehensive reuse subsystem and method for enhancing efficiency and reducing carbon in industrial wastewater treatment. This subsystem is independent of the main wastewater treatment system. By deeply washing and highly concentrating the Fenton iron sludge, it is then strategically applied to multiple key links of the main wastewater treatment system, such as anaerobic biochemical and flocculation air flotation sections. This not only significantly enhances the wastewater treatment capacity of each section, effectively improves the water quality purification effect, but also reduces the energy consumption, material consumption costs and carbon emission levels of each section, ultimately achieving the overall optimization and improvement of the entire main wastewater treatment system.

[0006] To achieve the above object, the present invention provides an iron sludge comprehensive reuse subsystem for enhancing efficiency and reducing carbon in industrial wastewater treatment, including a slurry preparation tank for iron sludge, a hydrocyclone system, a gravity sedimentation system and a reducing iron sludge tank connected in sequence;

[0007] The slurry preparation tank for iron sludge receives the filtered wet sludge from the neutralization sedimentation tank after Fenton and the treated effluent from the effluent discharge tank, and remakes the filtered wet sludge into iron mud slurry;

[0008] The hydrocyclone system receives the iron mud slurry, and through hydrocyclone washing and concentration, separates heavy mud slurry and light muddy water;

[0009] The gravity sedimentation system receives the heavy mud slurry, and through gravity sedimentation, separates the upper partial oxidation type heavy mud slurry and the lower partial reduction type heavy mud slurry;

[0010] The reducing iron sludge tank receives and stores the partial reduction type heavy mud slurry discharged from the gravity sedimentation system and the precipitated iron sludge discharged from the iron salt neutralization sedimentation tank to form mixed iron sludge.

[0011] Preferably, the mass ratio of the filtered wet sludge to the treated effluent in the slurry preparation tank for iron sludge is 1:5 to 1:100.

[0012] Preferably, the hydrocyclone system is arranged directly above the gravity sedimentation system, and the iron mud slurry is transported to the hydrocyclone system by a sludge pump.

[0013] The present invention also provides an iron sludge comprehensive reuse method for enhancing efficiency and reducing carbon in industrial wastewater treatment, including the following ways:

[0014] W1: The light muddy water separated by the hydrocyclone system is discharged into the anaerobic biochemical system, serving as an electron acceptor and detoxifying agent available to anaerobic bacteria, and realizing the enhancement of efficiency and reduction of carbon in the anaerobic biochemical process;

[0015] W2: The partially oxidized heavy mud separated by the heavy sedimentation system is discharged into the flocculation air flotation tank, acting as a flocculant to enhance the efficiency and reduce carbon emissions during the flocculation air flotation process;

[0016] W3: The partially oxidized heavy mud separated by the heavy sedimentation system is discharged into the iron ammonia oxidation MBR (membrane bioreactor) tank, acting as an electron acceptor available for iron ammonia oxidizing bacteria to enhance the efficiency and reduce carbon emissions during the iron ammonia oxidation process;

[0017] W4: The mixed mud formed by the partially reduced heavy mud and precipitated iron mud stored in the reducing iron mud tank is discharged into the Fenton oxidation system, acting as a catalyst and buffer for the Fenton oxidation reaction to enhance the efficiency and reduce carbon emissions during the Fenton oxidation process.

[0018] Preferably, in path W1, the dosage of the light muddy water is 1 - 8% of the mass of the mixed wastewater treated by the anaerobic biochemical system.

[0019] Preferably, in paths W2 and W3, the solid content of the partially oxidized heavy mud separated by the heavy sedimentation system is 5 - 15%.

[0020] Preferably, in path W2, the dosage of the partially oxidized heavy mud is 1 - 5% of the mass of the wastewater treated by the flocculation air flotation tank.

[0021] Preferably, in path W3, the dosage of the partially oxidized heavy mud is 1 - 2% of the volume of the wastewater treated by the iron ammonia oxidation MBR tank.

[0022] Preferably, in path W4, the dosage of the mixed iron mud is 2 - 8% of the volume of the wastewater treated by the Fenton oxidation system.

[0023] The technical principle of the present invention is as follows:

[0024] For the filtered wet mud generated in the post-Fenton neutralization sedimentation tank, the present invention has established an iron mud comprehensive recycling subsystem. Relatively clean treated effluent is drawn from the effluent discharge tank to make the wet mud into mud, and then it is washed and concentrated by a cyclone method, which can wash away most of the organic pollutants attached to the Fenton iron mud; Subsequently, the muddy water or mud obtained by rough separation is strategically applied to multiple key links such as anaerobic biochemical treatment and flocculation air flotation in the main wastewater treatment system, which can significantly promote the efficiency improvement and carbon emission reduction of the application section:

[0025] The Fenton oxidation process usually requires the adjustment of the wastewater pH with sulfuric acid and the use of ferrous sulfate as a catalyst. The sulfate radicals entering the wastewater can be converted into hydrogen sulfide by sulfate-reducing bacteria in the subsequent anaerobic biochemical system. The presence of hydrogen sulfide at a certain concentration will not only inhibit the activities of acid-producing bacteria and methanogens, reduce the treatment load and efficiency of the anaerobic system, but also corrode equipment, and even may cause malodor and poisoning of operating personnel. In the present invention, the light muddy water separated by the cyclone system is discharged into the anaerobic biochemical system. The light muddy water contains the washed organic matter and a certain content of iron sludge. The organic matter can be utilized by anaerobic bacteria to be converted into methane, and the introduction of the iron sludge can not only induce the dissimilatory iron reduction process, promote the hydrolysis and acidification of some macromolecular organic matter, but also serve as an electron acceptor that can be utilized by iron-reducing bacteria. The generated divalent iron further combines with hydrogen sulfide to form ferrous sulfide, realizing the detoxification of the wastewater. In addition, the presence of the iron sludge can also induce the formation of granular sludge in the anaerobic sludge. Generally speaking, the implementation of this strategy can increase the abundances and activities of iron-reducing bacteria, methanogens, etc. in the anaerobic biochemical system, thereby improving the removal efficiency of organic pollutants in the wastewater and the methane production, reducing the load and energy consumption of the subsequent aerobic treatment system, and promoting the high efficiency and low carbon of the entire biochemical treatment system.

[0026] The highly concentrated and difficult-to-degrade organic wastewater stored in the high-concentration collection tank often contains a large amount of pollutants such as organic suspended solids and hydrophobic oils. The use of the flocculation air flotation method not only has a high removal efficiency, but also generates a relatively small volume of sludge. The flocculants used in the conventional flocculation air flotation method are mainly polyferric sulfate or polyaluminum chloride. In the present invention, the washed and treated partial oxidation-type heavy mud separated by the heavy sedimentation system is used as a substitute for the above-mentioned flocculant for secondary utilization, supplemented by a coagulant aid. Similarly, pollutants can be effectively removed through mechanisms such as adsorption and net trapping, and there is no need to add liquid alkali to neutralize the flocculant, which not only greatly saves the chemical agent cost, but also reduces the overall output of iron sludge hazardous waste and saves the solid waste disposal cost.

[0027] Iron ammonia-oxidizing bacteria can use ferric iron as an electron acceptor to oxidize ammonia nitrogen into nitrogen gas, nitrite nitrogen or nitrate nitrogen, and reduce ferric iron to divalent iron. Compared with the existing commonly used nitrification-denitrification process, this new type of biological denitrification method does not require oxygen supply and the addition of organic carbon sources, and the main product is nitrogen gas, reducing the generation of N2O greenhouse gas. It belongs to a low-carbon wastewater treatment process and is particularly suitable for the deep removal of ammonia nitrogen in wastewater with a low carbon-nitrogen ratio. And it is found that compared with ferric iron forms such as FeCl3, Fe2O3, and Fe3O4, the Fe(OH)3 and α-FeOOH forms present in the Fenton iron sludge are more easily utilized by iron ammonia-oxidizing bacteria. In the present invention, the washed and treated partial oxidation-type heavy mud separated by the heavy sedimentation system is discharged into the iron ammonia-oxidizing MBR pool, which can achieve the deep removal of ammonia nitrogen in a low-carbon manner, and the generated divalent iron can be recovered by neutralization precipitation in the subsequent iron salt neutralization precipitation pool.

[0028] The combined process of micro-electrolysis and Fenton oxidation is widely used in treating wastewater containing refractory pollutants such as chlorinated aliphatic hydrocarbons, nitroaromatic compounds, azo dyes, and organochlorine pesticides. Micro-electrolysis usually uses iron powder or iron-carbon powder as a reducing agent. To ensure the effect of subsequent Fenton oxidation, the reducing agent is generally added in excess. Since the density of iron powder or iron-carbon powder is much greater than that of iron mud, the unreacted iron powder or iron-carbon powder in the subsequent neutralization sedimentation tank will sink to the bottom first and be discharged, resulting in waste of the reducing agent. The iron mud comprehensive recycling subsystem provided by the present invention can separate the relatively reducing heavy mud containing iron powder or iron-carbon powder through two-stage treatment of hydrocyclone and gravity sedimentation. After mixing it with the precipitated iron mud containing divalent iron recovered from the iron salt neutralization sedimentation tank, it is reused as a catalyst for the Fenton oxidation process, which can significantly reduce the dosage of the reducing agent and the output of iron mud hazardous waste. In addition, since the Fenton oxidation reaction mostly oxidizes and degrades macromolecular organic substances into small molecular organic acids, it causes the pH of the system to decrease, inhibits the transformation of ferric iron to ferrous iron, and thus reduces the removal rate of organic pollutants. After the mixed iron mud is reused in the Fenton oxidation system, the hydroxides in the iron mud can react with small molecular organic acids to achieve buffering, maintain the pH at the optimal range during the Fenton reaction, and improve the removal effect of organic pollutants.

[0029] In summary, the beneficial effects obtained by the present invention are as follows:

[0030] (1) The iron mud comprehensive recycling subsystem and method constructed by the present invention can achieve rough separation of different types of components of Fenton iron mud, and then by strategically applying the separated muddy water or mud to multiple key links such as anaerobic biochemical treatment and flocculation air flotation in the main wastewater treatment system, it can significantly strengthen the treatment capacity of each application section for pollutants such as organic matter, total nitrogen, and total phosphorus, and improve the pollutant removal efficiency and wastewater quality purification effect.

[0031] (2) The iron mud comprehensive recycling subsystem and method constructed by the present invention not only reduce the treatment load of the subsequent aerobic process by strengthening the removal effect of anaerobic biochemistry on organic matter, cut down the necessary aeration volume and energy consumption, but also establish an iron ammonia oxidation MBR system for deep ammonia nitrogen removal without oxygen supply and addition of organic carbon source based on Fenton iron mud, and finally achieve a reduction in the carbon emission of the entire main wastewater treatment system.

[0032] (3) The iron mud comprehensive recycling subsystem and method constructed by the present invention through recycling or secondary utilization of Fenton iron mud not only greatly save the chemical agent costs of flocculants and reducing agents, but also reduce the overall output of iron mud hazardous waste, and effectively cut down the operating cost of the main wastewater treatment system.

[0033] (4) The iron mud comprehensive recycling subsystem constructed by the present invention has the characteristics of external embedding, integration, and modularization, and its installation and operation process can achieve high-efficiency compatibility with the existing main wastewater treatment system without large-scale transformation. Brief Description of the Drawings

[0034] The drawings are used to provide further explanation of the present invention and form a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0035] Figure 1 is a roadmap of a subsystem and method for comprehensive reuse of iron sludge for enhancing efficiency and reducing carbon in industrial wastewater treatment according to the present invention.

[0036] Figure 2 is a schematic diagram of the equipment of a subsystem for comprehensive reuse of iron sludge for enhancing efficiency and reducing carbon in industrial wastewater treatment according to the present invention. In the figure:

[0037] 1. Iron sludge pulping tank; 11. Filtered wet sludge; 12. Treated effluent; 13. Iron mud slurry;

[0038] 2. Hydrocyclone system; 21. Lightweight muddy water; 22. Heavy mud slurry;

[0039] 3. Heavy sedimentation system; 31. Partially oxidized heavy mud slurry; 32. Partially reduced heavy mud slurry;

[0040] 4. Reductive iron sludge tank: 41. Precipitated iron sludge; 42. Mixed iron sludge. Detailed Embodiments

[0041] The present invention will be described and explained in detail below with reference to the drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and cannot be used to limit the protection scope of the present invention.

[0042] Embodiment 1

[0043] Figure 2 Shows an actual device system based on the iron sludge comprehensive reuse subsystem described in the present invention.

[0044] In the actual device system, the iron sludge pulping tank 1 receives the filtered wet sludge 11 from the post-Fenton neutralization sedimentation tank and the treated effluent 12 from the effluent discharge tank. The mass ratio of the filtered wet sludge 11 to the treated effluent 12 is controlled to be 1:5 to 1:100, and the filtered wet sludge 11 is remade into a uniform iron mud slurry 13 by hydrodynamic shearing. The cyclone system 2 is arranged directly above the heavy sedimentation system 3. The iron mud slurry 13 is transported to the cyclone system 2 by a sludge pump. Through the cyclone action, the light muddy water 21 with a smaller density and a small amount of iron sludge is discharged from the top outlet, while the heavy mud slurry 22 with a larger density is thrown towards the inner walls around by centrifugal force, then sinks and is discharged into the heavy sedimentation system 3 through the bottom outlet, thus realizing the concentration of the iron mud slurry 13. The heavy mud slurry 22 entering the heavy sedimentation system 3 freely settles under the action of gravity. Since the density of iron powder / iron-carbon powder in the mud slurry is much greater than that of hydroxide iron sludge, the upper partial oxidation-type heavy mud slurry 31 (mainly hydroxide iron sludge) and the lower partial reduction-type heavy mud slurry 32 (containing iron powder / iron-carbon powder and hydroxide iron sludge) can be roughly separated. The partial reduction-type heavy mud slurry 32 accumulates in the bottom tank of the heavy sedimentation system 3. The partial reduction-type heavy mud slurry 32 is discharged into the closed reducing iron sludge tank 4 by a sludge pump. In addition, the precipitated iron sludge 41 containing divalent iron discharged from the iron salt neutralization sedimentation tank is also discharged into the reducing iron sludge tank 4, and the two form a mixed iron sludge 42 under the stirring action. The mixed iron sludge 42 can be discharged into the Fenton oxidation system.

[0045] Example 2

[0046] This Example 2 verifies the effect of the light muddy water described in Example 1 on enhancing the efficiency and reducing carbon in the anaerobic biochemical process.

[0047] The anaerobic biochemical process is as follows: The Fenton iron sludge from a pesticide enterprise wastewater treatment system in Yangzhou, Jiangsu is treated by the device system in Example 1 to obtain light muddy water. The COD of the wastewater in the biochemical regulation tank of this pesticide enterprise is about 6200 mg / L, and this wastewater is used as the treatment object for the experiment. The sludge from the anaerobic system is taken, cleaned and evenly divided, and then filled into two 5-L anaerobic bench-scale devices respectively. The hydraulic retention time is controlled to be 3 d, and other conditions are controlled to be the same. A control group is set: Group A enters the wastewater from the biochemical regulation tank, and Group B enters the mixed wastewater of the biochemical regulation tank and light muddy water (the proportion of light muddy water is 5%), and continuous influent cultivation treatment is carried out for more than 30 d.

[0048] The treatment effect is shown in Table 1. The results show that the introduction of light muddy water can effectively improve the removal effect of the anaerobic biochemical process on COD and TP, reduce the load of the subsequent aerobic process, and cut down energy consumption and carbon emissions.

[0049] Table 1 Results of the light muddy water enhancing efficiency and reducing carbon in the anaerobic biochemical process

[0050] Project Group A Group B Continuous influent COD (mg / L) 6279 6134 Effluent COD (mg / L) after 20 days 2456 2044 Effluent COD (mg / L) after 30 days 2129 1523 Influent TP (mg / L) 4.3 4.1 Effluent TP (mg / L) after 20 days 2.9 0.03 Effluent TP (mg / L) after 30 days 2.6 0.04

[0051] Example 3

[0052] In this Example 3, the effect of the partial oxidation type heavy mud described in Example 1 on enhancing the efficiency and reducing carbon in the flocculation air flotation process was verified.

[0053] The flocculation air flotation process was as follows: The Fenton iron mud from a pesticide enterprise wastewater treatment system in Yangzhou, Jiangsu was treated using the device system in Example 1 to obtain a partial oxidation type heavy mud, and the solid content in this partial oxidation type heavy mud was approximately 5%. The COD content of the wastewater in the high-concentration collection tank of this pesticide enterprise was 32449 mg / L, containing a certain amount of suspended solids and hydrophobic oils. This wastewater was used as the treatment object for the experiment. After adjusting the pH of the high-concentration collection tank wastewater to 6 - 9, a certain proportion of polyferric sulfate (11 wt% total iron) or partial oxidation type heavy mud (adding liquid caustic soda to adjust the pH to 6 - 9 after adding polyferric sulfate) was added, stirred evenly and reacted for 10 min, and then air flotation treatment was carried out using a 2L small air flotation device.

[0054] The treatment effects are shown in Table 2. The results show that: When the dosage of the partial oxidation type heavy mud is appropriate, it can achieve the same or even better COD removal effect as polyferric sulfate, and can replace polyferric sulfate as a flocculant in the flocculation air flotation process, saving the chemical agent cost.

[0055] Table 2 Results of the partial oxidation type heavy mud on enhancing the efficiency and reducing carbon in the flocculation air flotation process

[0056] Project COD (mg / L) Wastewater from high-concentration collection tank 32449 Effluent after adding 3‰ ferric polysulfate (11wt% total iron) 26374 Effluent after adding 1% partially oxidized heavy mud 27299 Effluent after adding 2% partially oxidized heavy mud 25195

[0057] Example 4

[0058] In this Example 4, the effect of the partial oxidation type heavy mud described in Example 1 on enhancing the efficiency and reducing carbon in the iron ammonia oxidation process was verified.

[0059] The iron ammonia oxidation process was as follows: The Fenton iron mud from a pesticide enterprise wastewater treatment system in Yangzhou, Jiangsu was treated using the device system in Example 1 to obtain a partial oxidation type heavy mud, and the solid content in this partial oxidation type heavy mud was approximately 5%. The high-salt water of this pesticide enterprise was subjected to triple-effect evaporation of salt to produce a high ammonia-nitrogen wastewater with a low carbon-nitrogen ratio, and the ammonia-nitrogen content was approximately 1400 mg / L. This wastewater was diluted 10 times and used as the treatment object for the experiment. 1% volume of the partial oxidation type heavy mud was added to the diluted wastewater, then the pH was adjusted to 4 - 5, and continuous influent treatment was carried out in a reactor containing the iron ammonia oxidation sludge that had been cultivated.

[0060] The treatment effects are shown in Table 3. The results show that: The iron mud produced in the Fenton process can be used as an electron acceptor by iron ammonia-oxidizing bacteria to achieve effective reduction of ammonia-nitrogen, and this process does not require oxygen supply and addition of organic carbon sources.

[0061] Table 3 Results of the partial oxidation type heavy mud on enhancing the efficiency and reducing carbon in the iron ammonia oxidation process

[0062] Project Ammonia nitrogen (mg / L) Continuous influent 138 Effluent after 20 days 66 Effluent after 30 days 56

[0063] Example 5

[0064] This Example 5 verifies the effect of the mixed iron sludge described in Example 1 on enhancing carbon reduction in the micro-electrolysis-Fenton oxidation process.

[0065] The micro-electrolysis-Fenton oxidation process is as follows: The Fenton iron sludge from a pesticide enterprise wastewater treatment system in Yangzhou, Jiangsu is treated using the device system in Example 1 to obtain the mixed iron sludge. The flocculation and air flotation effluent in Example 3 is used as the treatment object for the experiment. The flocculation and air flotation effluent is taken, the pH is adjusted to 3, and it is divided into two groups. Group A adds 2 g / L of iron-carbon powder for micro-electrolysis, and then adds 3% by volume of hydrogen peroxide (30% concentration) to initiate the Fenton reaction. Group B adds 1 g / L of iron-carbon powder for micro-electrolysis, and then immediately adds 2% by volume of the mixed iron sludge after adding 3% by volume of hydrogen peroxide (30% concentration) to initiate the Fenton reaction. The entire Fenton reaction time is 3 h.

[0066] The treatment effects are shown in Table 4. The results show that using the mixed iron sludge as a supplementary catalyst in the micro-electrolysis-Fenton oxidation system can achieve the same or even better COD removal effect when the dosage is sufficient, and can reduce the initial dosage of iron-carbon powder, saving the chemical agent cost.

[0067] Table 4 Results of the mixed iron sludge enhancing carbon reduction in the micro-electrolysis-Fenton oxidation process

[0068] Project COD (mg / L) Influent for Fenton treatment 25195 Effluent of Group A 17269 Effluent of Group B 16423

[0069] Finally, it should be noted that the above embodiments only represent several implementation manners of the present invention and are not intended to limit the present invention. For those of ordinary skill in the art, any modifications, equivalent replacements, improvements, etc. made without departing from the concept of the present invention should be included within the protection scope of the present invention. Therefore, the protection scope of this invention patent shall be subject to the appended claims.

Claims

1. An iron sludge comprehensive recycling subsystem for enhancing the efficiency and reducing the carbon emissions of industrial wastewater treatment, characterized in that, It includes a ferric sludge pulping tank (1), a cyclone system (2), a heavy sedimentation system (3) and a reducing ferric sludge tank (4) connected in sequence; The ferric sludge pulping tank (1) receives the filtered wet sludge (11) from the neutralization sedimentation tank after Fenton treatment and the treated effluent (12) from the effluent discharge tank, and remakes the filtered wet sludge (11) into ferric sludge slurry (13); The cyclone system (2) receives the ferric sludge slurry (13), and through cyclone washing and concentration, separates out heavy sludge (22) and light muddy water (21); The heavy sedimentation system (3) receives the heavy sludge (22), and through gravity sedimentation, separates out the upper partial oxidation type heavy sludge (31) and the lower partial reduction type heavy sludge (32); The reducing ferric sludge tank (4) receives and stores the partial reduction type heavy sludge (32) discharged from the heavy sedimentation system (3) and the precipitated ferric sludge (41) discharged from the ferric salt neutralization sedimentation tank, and forms mixed ferric sludge (42).

2. The system according to claim 1, wherein The mass ratio of the filtered wet sludge (11) to the treated effluent (12) in the ferric sludge pulping tank (1) is 1:5 to 1:

100.

3. The system according to claim 1, wherein The cyclone system (2) is arranged directly above the heavy sedimentation system (3), and the ferric sludge slurry (13) is transported to the cyclone system (2) by a sludge pump.

4. A method for comprehensively recycling iron sludge to enhance the efficiency of industrial wastewater treatment and reduce carbon emissions based on the iron sludge comprehensive recycling subsystem described in any one of claims 1-3, characterized in that, It includes the following paths: W1: The light muddy water (21) separated by the cyclone system (2) is discharged into the anaerobic biochemical system; W2: The partial oxidation type heavy sludge (31) separated by the heavy sedimentation system (3) is discharged into the flocculation air flotation tank; W3: The partial oxidation type heavy sludge (31) separated by the heavy sedimentation system (3) is discharged into the iron ammonia oxidation MBR tank; W4: The mixed ferric sludge (42) formed by the partial reduction type heavy sludge (32) and the precipitated ferric sludge (41) stored in the reducing ferric sludge tank (4) is discharged into the Fenton oxidation system.

5. The method according to claim 4, characterized in that, In path W1, the dosage of the light muddy water (21) is 1 - 8% of the mass of the mixed wastewater treated by the anaerobic biochemical system.

6. The method according to claim 4, wherein In paths W2 and W3, the solid content of the partial oxidation type heavy sludge (31) separated by the heavy sedimentation system (3) is 5 - 15%.

7. The method according to claim 4, characterized in that In path W2, the dosage of the partial oxidation type heavy sludge (31) is 1 - 5% of the mass of the wastewater treated by the flocculation air flotation tank.

8. The method according to claim 4, characterized in that In path W3, the dosage of the partial oxidation type heavy sludge (31) is 1 - 2% of the volume of the wastewater treated by the iron ammonia oxidation MBR tank.

9. The method according to claim 4, wherein In path W4, the dosage of the mixed ferric sludge (42) is 2 - 8% of the volume of the wastewater treated by the Fenton oxidation system.

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