Fenton iron mud treatment method and device

Abstract

The invention provides a Fenton iron sludge treatment method and device, and the Fenton iron sludge treatment method comprises the following steps: enabling Fenton iron sludge to enter an iron reduction unit, carrying out reduction treatment under the action of dissimilatory iron reducing bacteria, and reducing ferric iron in the Fenton iron sludge into ferrous iron through the reduction treatment to obtain reduced iron sludge; enabling at least part of the reduced iron sludge to enter a bioleaching unit, and performing bioleaching treatment under the action of specific microorganisms to obtain a first mixed material liquid; carrying out dehydration treatment on the first mixed material liquid to respectively obtain a water phase and dehydrated sludge; and returning the aqueous phase to the bioleaching system to participate in the bioleaching treatment. The technical problems that in the prior art, acid liquid needs to be additionally added, a large amount of strongly acidic water is generated, environmental pollution is easily caused, iron elements cannot be recycled, and cost is high can be solved.

Description

Technical Field

[0001] The invention relates to the field of environmental engineering, and in particular to a Fenton iron sludge treatment method and device. Background Art

[0002] Fenton iron sludge is an iron-containing sludge produced during the Fenton oxidation process to treat wastewater. The Fenton oxidation process is an advanced oxidation technology that is widely used to treat high-concentration, difficult-to-degrade organic wastewater such as dye wastewater, landfill leachate, and papermaking wastewater. 2+ It reacts with H2O2 to generate highly oxidizing hydroxyl free radicals, thereby oxidizing and decomposing organic pollutants in the wastewater. During the treatment process, a large amount of iron-containing sludge, namely Fenton iron sludge, will be produced. The iron sludge contains a large amount of organic matter, parasitic pathogens, heavy metals and other impurities. At the same time, the dehydration performance of Fenton iron sludge is poor, so that the moisture content of the dehydrated iron sludge is still high. If Fenton iron sludge is not properly treated and is directly discharged into the environment, it will occupy a large amount of land area, destroy the soil structure, pollute water resources, and bring serious environmental pollution problems. At the same time, if the heavy metals in the iron sludge are transferred to the soil or groundwater with the leachate, it will also cause secondary pollution.

[0003] In the related technologies, the treatment methods for Fenton iron sludge and other sludge mainly include acid dissolution method, bioleaching method, etc. However, the dehydration efficiency of Fenton iron sludge by existing treatment methods still needs to be further improved. At the same time, there are problems such as the need to add additional acid, the generation of a large amount of strongly acidic water, easy to cause environmental pollution, the inability to recycle iron elements, and high cost.

[0004] Specifically, the acid dissolution method requires a large amount of acid solution, which has the problems of high cost and easy environmental pollution. For example, patent document CN 110877956A discloses a device and method for treating Fenton iron mud, which reduces the trivalent iron in the Fenton iron mud to divalent iron by microorganisms containing iron-reducing bacteria, and then passes the mixed solution containing divalent iron produced after the reaction into an acid dissolution tank, adds acid solution to the acid dissolution tank 4, and then allows static precipitation. The supernatant containing divalent iron ions is returned to the Fenton reactor, so that under acidic conditions, the divalent iron ions are not easily oxidized to trivalent iron and are conducive to starting the Fenton reaction, thereby achieving the purpose of treating the Fenton iron mud. This treatment method requires additional addition of acid solution, and when the supernatant containing divalent iron ions is refluxed to the Fenton reactor, the COD that has not been biodegraded is also refluxed, increasing the Fenton treatment load.

[0005] In addition, bioleaching is a process that utilizes the life activities of Acidithiobacillus bacteria to oxidize ferrous ions and reduced sulfur into high-valent states, producing H +And create a strong oxidizing environment. This technology can use acidophilic thiobacillus bacteria to act on sludge, improve the dewatering performance of sludge, and can achieve the effects of eliminating odorous substances, killing or inhibiting pathogens, etc. However, the current biological leaching process for sludge treatment will produce strongly acidic water, which is corrosive, difficult to dispose of, and easily causes environmental pollution. For example, patent document CN 106186595A discloses a process for treating sludge using an integrated biological leaching treatment device. The sludge is treated through a biological leaching process, and the filtrate produced is a strongly acidic water body, which is corrosive and difficult to dispose of. Summary of the invention

[0006] The present invention provides a Fenton iron sludge treatment method and device, so as to at least solve the technical problems existing in the prior art, such as the need to add additional acid solution, the generation of a large amount of strongly acidic water, the easy environmental pollution, the inability to recycle the iron element, and the high cost.

[0007] In one aspect of the present invention, a Fenton iron sludge treatment method is provided, comprising the following steps: allowing the Fenton iron sludge to enter an iron reduction unit, and performing a reduction treatment under the action of dissimilatory iron-reducing bacteria, thereby reducing the trivalent iron in the Fenton iron sludge to divalent iron to obtain reduced iron sludge; allowing at least part of the reduced iron sludge to enter a bioleaching unit, and performing a bioleaching treatment under the action of specific microorganisms to obtain a first mixed liquid; dehydrating the first mixed liquid to obtain an aqueous phase and dehydrated sludge, respectively; and returning the aqueous phase to the bioleaching unit to participate in the bioleaching treatment.

[0008] According to one embodiment of the present invention, the iron reduction unit includes a microbial fuel cell, which includes a bioanode chamber, a biocathode chamber, and a proton exchange membrane arranged between the bioanode chamber and the biocathode chamber; the bioanode chamber is provided with a bioanode material, and the bioanode material is inoculated with the dissimilatory iron-reducing bacteria; oxygen exists in the biocathode chamber; the Fenton iron mud enters the bioanode chamber for the reduction treatment; preferably, the reduction treatment time is 6 to 12 hours.

[0009] According to one embodiment of the present invention, the iron reduction unit includes an iron reduction reactor, and the Fenton iron mud enters the iron reduction reactor for the reduction treatment; wherein the conditions of the reduction treatment are: temperature of 25°C to 35°C, pH of 6.5 to 7.5, and residence time of 12 to 24 hours.

[0010] According to one embodiment of the present invention, the specific microorganisms include Acidithiobacillus; preferably, the Acidithiobacillus includes Thiobacillus ferrooxidans and / or Thiobacillus thiooxidans.

[0011] According to one embodiment of the present invention, before the bioleaching treatment, a bacterial solution containing the specific microorganism is inoculated in the bioleaching unit, the bioleaching unit contains sludge for inoculation of the specific microorganism, and the cell density of the specific microorganism in the bacterial solution is 10 7 ~10 8 / mL, and in terms of volume ratio, the volume of the bacterial liquid accounts for 5% to 20% of the sum of the volume of the bacterial liquid and the volume of the sludge that can be used for inoculation of the specific microorganisms.

[0012] According to one embodiment of the present invention, the temperature of the bioleaching treatment is 25°C to 35°C; and / or, during the bioleaching treatment, the residence time of the reduced iron mud is 40 to 60 hours; and / or, during the bioleaching treatment, the reduced iron mud entering the bioleaching unit is aerated by an aerator connected to the bioleaching unit; and / or, the pH of the first mixed liquid is 2 to 3; and / or, the dissolved oxygen of the first mixed liquid in the bioleaching unit is 3 to 6 mg / L; and / or, the bioleaching unit includes nutrients for providing nutrition to the specific microorganisms, the nutrients include an iron source and / or a sulfur source, the iron source includes FeSO4 and / or FeCl2, and the sulfur source includes S and / or Na2S2O3.

[0013] According to one embodiment of the present invention, a plate filter press and / or a belt filter press is used to perform the dehydration treatment on the first mixed liquid.

[0014] According to one embodiment of the present invention, the process of returning the water phase to the bioleaching system unit to participate in the bioleaching treatment includes: mixing the water phase and part of the reduced iron mud to obtain a second mixed liquid; and allowing the second mixed liquid to enter the bioleaching system unit to participate in the bioleaching treatment.

[0015] Another aspect of the present invention provides a Fenton iron sludge treatment device, the Fenton iron sludge treatment device comprising: an iron reduction unit for performing the reduction treatment; the iron reduction unit comprises a first reduced iron sludge outlet and a second reduced iron sludge outlet; a bioleaching unit for performing the bioleaching treatment; the bioleaching unit comprises a first reduced iron sludge inlet, a first mixed liquid outlet and a second mixed liquid inlet, the first reduced iron sludge inlet is connected to the first reduced iron sludge outlet of the iron reduction unit; a dehydration unit for performing the dehydration treatment; the dehydration unit comprises a first mixed liquid inlet and an aqueous phase outlet, the first mixed liquid inlet is connected to the first mixed liquid outlet of the bioleaching unit; a bypass ferrous dissolution unit comprises a second reduced iron sludge inlet, an aqueous phase inlet and a second mixed liquid outlet, the second reduced iron sludge inlet is connected to the second reduced iron sludge outlet of the iron reduction unit, the aqueous phase inlet is connected to the aqueous phase outlet of the dehydration unit, and the second mixed liquid outlet is connected to the second mixed liquid inlet of the bioleaching unit.

[0016] According to one embodiment of the present invention, the iron reduction unit includes a microbial fuel cell and / or an iron reduction reactor; and / or the Fenton iron sludge device also includes an air aerator connected to the bioleaching unit.

[0017] The implementation of the present invention has at least the following beneficial effects:

[0018] (1) The trivalent iron in the Fenton iron sludge is reduced to divalent iron by an iron reduction unit, so that the iron in the reduced iron sludge exists in the form of divalent iron. At least part of the reduced iron sludge enters the bioleaching unit for bioleaching treatment, and the divalent iron therein can be used as a nutrient substrate (or energy substrate) for specific microorganisms. While the bioleaching is used to dehydrate, sterilize and deodorize the reduced iron sludge, the resource utilization of the iron in the Fenton iron sludge can be achieved, thereby reducing the reaction cost of bioleaching;

[0019] (2) The first mixed liquid produced after the bioleaching treatment is dehydrated, and the water phase produced after the dehydration treatment is a strongly acidic water body. The water phase is fed back to the bioleaching system to participate in the bioleaching treatment, providing a strongly acidic environment for the materials in the bioleaching system, which is beneficial to the dissolution of the divalent iron in the reduced iron sludge entering the bioleaching system into ionic divalent iron, which serves as an energy substrate for specific microorganisms in the bioleaching unit.

[0020] Therefore, the present invention recovers the strongly acidic aqueous phase generated after the first mixed liquid is dehydrated, and is used to dissolve the divalent iron in the reduced iron mud entering the bioleaching system into an ionic state, and then participates in the bioleaching reaction. On the one hand, the divalent iron dissolved in the ionic state can be used as an energy substrate for specific microorganisms in the bioleaching unit, which can reduce the nutrients added to the bioleaching system to provide nutrition for specific microorganisms, reduce costs, and achieve efficient utilization of the iron element in the Fenton iron mud; on the other hand, the strongly acidic aqueous phase generated after the dehydration treatment is returned to the bioleaching system for recycling, which can avoid the additional addition of acidic agents such as sulfuric acid, nitric acid, hydrochloric acid, acetic acid, etc. to the bioleaching system, thereby reducing costs and avoiding the additional introduction of other impurity components into the aqueous phase and dehydrated sludge. At the same time, the discharge of the strongly acidic aqueous phase can be reduced, environmental pollution can be avoided, and the cost of post-treatment of the strongly acidic aqueous phase can be reduced, thereby achieving the recycling of acidic water without the need for additional addition of acid, avoiding environmental pollution, reducing costs, and recycling iron elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention discloses a Fenton iron sludge treatment device according to an embodiment of the present invention.

[0022] Explanation of the reference numerals: 1: iron reduction unit; 2: bioleaching unit; 3: dehydration unit; 4: bypass ferrous dissolution unit; 5: reflux unit; 6: aeration aerator; a: Fenton iron sludge; b1: first reduced iron sludge; b2: second reduced iron sludge c: first mixed liquid; d: aqueous phase; e: second mixed liquid; f: dehydrated sludge; g: sludge. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0024] The present invention provides a Fenton iron mud a treatment method, see Figure 1The method comprises the following steps: allowing Fenton iron mud a to enter an iron reduction unit (or iron reduction treatment system) 1, and subjecting it to reduction treatment under the action of dissimilatory iron-reducing bacteria, thereby reducing the trivalent iron in the Fenton iron mud a to divalent iron to obtain reduced iron mud; allowing at least part of the reduced iron mud (hereinafter referred to as the first reduced iron mud b1 that enters the bioleaching unit) to enter a bioleaching unit (or sludge bioleaching system) 2, and subjecting it to bioleaching treatment under the action of specific microorganisms to obtain a first mixed liquid c; subjecting the first mixed liquid c to dehydration treatment to obtain a water phase d and a dehydrated sludge f, respectively; and returning the water phase d to the bioleaching unit 2 to participate in the bioleaching treatment.

[0025] In this way, in the iron reduction unit 1, the trivalent iron in the Fenton iron sludge a is reduced to divalent iron by the dissimilatory iron-reducing bacteria, so that the iron element in the reduced iron sludge is mainly divalent iron. After the reduced iron sludge enters the bioleaching unit 2, it is subjected to bioleaching treatment under the action of specific microorganisms. In this process, the divalent iron in the reduced iron sludge is dissolved into an ionic state by the strong acidic solution produced by the bioleaching reaction in the bioleaching unit 2. The ionic divalent iron can be used as a nutrient substrate for the bioleaching reaction, so that the iron element in the Fenton iron sludge a can be utilized as a resource while using bioleaching to dehydrate, sterilize and deodorize the sludge, thereby improving the bioleaching efficiency and reducing the reaction cost of bioleaching.

[0026] In addition, the water phase d generated after the first mixed liquid c is dehydrated is a strongly acidic water body (or a strongly acidic water phase). After the strongly acidic water body is recovered and mixed with part of the above-mentioned reduced iron mud, it can promote the dissolution of the divalent iron produced by the iron reduction unit 1 into an ionic state, and then participate in the biological leaching reaction, thereby realizing the recycling of the strongly acidic water body, avoiding the additional addition of chemical agents such as sulfuric acid, nitric acid, hydrochloric acid, acetic acid, etc., avoiding the introduction of other impurities, reducing the treatment cost of the strongly acidic water body and the cost of the biological leaching reaction, and improving the efficiency of the biological leaching reaction.

[0027] In some embodiments, the iron reduction unit 1 may include a microbial fuel cell including a bioanode chamber, a biocathode chamber, and a proton exchange membrane disposed between the bioanode chamber and the biocathode chamber.

[0028] Specifically, the bioanode chamber is provided with a bioanode material, on which dissimilatory iron-reducing bacteria are inoculated, and oxygen exists in the biocathode chamber, which may include cathode materials such as carbon materials such as graphite fiber brushes and / or carbon felt.

[0029] Specifically, the dissimilatory iron-reducing bacteria may include one or more of Shewanella, Geobacter, and Clostridium.

[0030] In some embodiments, a gas containing oxygen may exist in the biocathode chamber, and the gas containing oxygen may specifically be air, that is, air may exist in the biocathode chamber, so that oxygen exists in the biocathode chamber.

[0031] Specifically, Fenton iron mud a enters the above-mentioned biological anode chamber for reduction treatment. During the reduction treatment process, the organic matter adsorbed by the Fenton iron mud in the biological anode chamber is oxidized and degraded, and at the same time, trivalent iron Fe(III) is reduced to divalent iron Fe(II) under the action of dissimilatory iron-reducing bacteria, and the oxygen in the biological cathode chamber is reduced as an electron acceptor. The H generated in the biological anode chamber is + It passes through the proton exchange membrane to the cathode chamber and reacts with the reduced oxygen to produce water.

[0032] In the embodiment of the present invention, conventional proton exchange membranes in the art may be used.

[0033] Specifically, the Fenton iron mud a enters the above-mentioned biological anode chamber for reduction treatment, and the reduction treatment time can be 6 to 12 hours, for example, 6 hours, 8 hours, 10 hours, 12 hours or a range consisting of any two of them.

[0034] In other embodiments, the iron reduction unit 1 may be a microbial iron reduction reactor, and the Fenton iron sludge a enters the iron reduction reactor for reduction treatment.

[0035] Specifically, when the reduction treatment is carried out using an iron reduction reactor, the reduction treatment temperature (reaction temperature in the iron reduction unit 1) can be 25-35°C, for example, 25°C, 27°C, 29°C, 31°C, 33°C, 35°C or a range consisting of any two thereof. During the reduction treatment, the pH of Fenton iron mud a can be 6.5-7.5, for example, 6.5, 6.7, 6.9, 7.1, 7.3, 7.5 or a range consisting of any two thereof. The residence time of Fenton iron mud a can be 12-24h, for example, 12h, 14h, 16h, 18h, 20h, 22h, 24h or a range consisting of any two thereof. In this way, the trivalent iron in Fenton iron mud a is reduced to divalent iron, providing nutrition for specific microorganisms in the bioleaching system.

[0036] In a specific implementation, the pH of Fenton iron mud a maintained during the reduction treatment may be 6.5-7.5, and the pH of Fenton iron mud a in the iron reduction unit 1 may be adjusted by alkali, which may include an inorganic alkali, such as sodium hydroxide.

[0037] In some embodiments, the specific microorganisms may include Acidithiobacillus, which may include Thiobacillus ferrooxidans and / or Thiobacillus thiooxidans.

[0038] In a specific implementation, before the bioleaching treatment, the bacterial solution containing the above-mentioned specific microorganisms can be inoculated into the bioleaching unit 2, and the bioleaching unit 2 is added with sludge g for inoculation of specific microorganisms. The bacterial solution containing the specific microorganisms can be inoculated into the sludge g in the bioleaching unit 2, and the bacterial cell density in the bacterial solution can be 10 7 ~10 8 / mL (for example, the bacterial density can be 10 8 / mL), and in terms of volume ratio, the volume of the bacterial liquid can account for 5% to 20% of the sum of the volume of the bacterial liquid and the volume of the sludge g in the bioleaching unit 2 that can be used for inoculation of specific microorganisms, for example, 5%, 10%, 15%, 20% or a range consisting of any two of them.

[0039] The sludge g in the bioleaching unit 2 that can be used for inoculation of specific microorganisms can be ordinary municipal sludge.

[0040] Specifically, the bioleaching unit 2 may be a conventional bioleaching reactor in the art, and is not particularly limited thereto.

[0041] In some embodiments, the temperature of the bioleaching treatment (or the temperature of the bioleaching reaction) can be 25°C to 35°C, for example, 25°C, 27°C, 28°C, 29°C, 31°C, 33°C, 35°C or a range consisting of any two thereof.

[0042] In some embodiments, during the bioleaching process, the residence time of the first reduced iron mud b1 entering the bioleaching unit 2 may be 40 to 60 hours, such as 40 hours, 45 hours, 50 hours, 55 hours, 60 hours or a range consisting of any two thereof.

[0043] In addition, the pH of the first mixed liquid c may be in the range of 2 to 3, for example, 2, 2.2, 2.4, 2.6, 2.8, 3 or any two thereof.

[0044] In addition, the dissolved oxygen (DO) of the first mixed liquid c in the bioleaching unit 2 can be 3-6 mg / L, for example, 3 mg / L, 4 mg / L, 5 mg / L, 6 mg / L or any two thereof.

[0045] In addition, during the bioleaching process, the reduced iron sludge entering the bioleaching unit 2 may be aerated by the air aerator 6 connected to the bioleaching unit 2 .

[0046] In the embodiment of the present invention, the nutrients (or nutrient substrates) for specific microorganisms in the bioleaching reaction can be obtained from Fenton iron mud a, or can be additionally added.

[0047] In some embodiments, the nutrient substrate for specific microorganisms may include an iron source and / or a sulfur source. The iron source may be FeSO4 and / or FeCl2, and the sulfur source may be S and / or Na2S2O3.

[0048] As mentioned above, the ferrous iron in the reduced iron mud entering the bioleaching unit 2 is dissolved into ionic ferrous iron in a strong acidic environment. The ionic ferrous iron can be used as a nutrient substrate for specific microorganisms in the bioleaching reaction, and the Fenton iron mud a can be utilized as a resource while dehydrating, sterilizing and deodorizing the sludge, thereby reducing the reaction cost of bioleaching. Generally, the reduced iron mud entering the bioleaching unit 2 can provide a ferrous iron source such as FeSO4 and / or FeCl2 as a nutrient for specific microorganisms.

[0049] In the above-mentioned treatment process of Fenton iron mud, the Fenton iron mud is firstly reduced by dissimilatory iron-reducing bacteria and then enters the bioleaching unit 2 for bioleaching treatment, so that the dewatering performance of the Fenton iron mud is improved.

[0050] Specifically, the obtained first mixed liquid c can be dehydrated by a dehydration unit (or sludge solid-liquid separation system) 3. The dehydration unit 3 can be a filter press, specifically a plate filter press and / or a belt filter press. After dehydration, the obtained filtrate is the above-mentioned water phase d.

[0051] In the embodiment of the present invention, a conventional plate filter press (plate and frame filter press) and / or a belt filter press in the art may be used for dehydration treatment.

[0052] In some embodiments, the process of returning the water phase d to the bioleaching unit 2 to participate in the bioleaching treatment may include: mixing the water phase d with a portion of the reduced iron sludge (the second reduced iron sludge b2) to obtain a second mixed liquid e; and allowing the second mixed liquid e to enter the bioleaching unit 2 to participate in the bioleaching treatment.

[0053] Specifically, the water phase d obtained after dehydration of the first mixed liquid c is a strongly acidic water body, and the strongly acidic water body enters the bypass ferrous dissolution unit (or bypass ferrous dissolution system) 4 through the reflux unit (or sludge filtrate reflux system) 5, and part of the reduced iron mud (second reduced iron mud b2) enters the bypass ferrous dissolution unit 4, and the strongly acidic water body entering the bypass ferrous dissolution unit 4 and the reduced iron mud (i.e., the second reduced iron mud b2) entering the bypass ferrous dissolution unit 4 are mixed to form a second mixed liquid e, and then the second mixed liquid e enters the bioleaching unit 2 to participate in the bioleaching reaction. Among them, in the bypass ferrous iron dissolution unit 4, the water phase d is a strongly acidic water body, and the acidic environment provided can promote the dissolution of the divalent iron in the second reduced iron mud b2 into ionic divalent iron. The formed second mixed liquid e is also strongly acidic. After the second mixed liquid e enters the bioleaching unit 2, it provides a strongly acidic environment for the reaction system in the bioleaching unit 2, and promotes the dissolution of the divalent iron in the first reduced iron mud b1 entering the bioleaching unit 2 into ionic divalent iron. Therefore, in the bioleaching unit 2, the divalent iron in the reduced mud output by the iron reduction unit is promoted to dissolve into ionic divalent iron, and nutrition is provided for the specific microorganisms in the bioleaching unit 2. Through the above process, the water phase utilization of the water phase d is realized, so that it participates in the bioleaching reaction of the bioleaching unit 2, and the efficiency of the bioleaching reaction is improved.

[0054] Specifically, the reflux unit 5 is connected between the dehydration unit 3 and the bypass ferrous dissolution unit 4, and is used to connect the dehydration unit 3 and the bypass ferrous dissolution unit 4, so that the water phase d generated by the dehydration unit 3 can flow back to the bypass ferrous dissolution unit 4 through the reflux unit 5. Among them, the reflux unit 5 can be a connecting structure such as a pipeline connecting the dehydration unit 3 and the bypass ferrous dissolution unit 4.

[0055] In some embodiments, the process of mixing the water phase d and the second reduced iron mud b2 can be performed at room temperature, that is, the temperature of the bypass ferrous dissolution unit 4 can be room temperature.

[0056] The present invention also provides a Fenton iron mud a treatment device, comprising:

[0057] The iron reduction unit 1, i.e., used for reduction treatment, may include a first reduced iron mud outlet and a second reduced iron mud outlet;

[0058] The bioleaching unit 2 is used for bioleaching treatment, and may include a first reduced iron mud inlet, a first mixed liquid outlet, and a second mixed liquid inlet, wherein the first reduced iron mud inlet is connected to the first reduced iron mud outlet of the iron reduction unit 1;

[0059] The dehydration unit 3 is used for dehydration treatment and may include a first mixed liquid inlet and a water phase outlet, wherein the first mixed liquid inlet is connected to the first mixed liquid outlet of the bioleaching unit 2;

[0060] In a specific embodiment, the dehydration unit 3 may further include a dehydrated sludge outlet for outputting the dehydrated sludge f;

[0061] The bypass ferrous dissolution unit 4 may include a second reduced iron mud inlet, a water phase inlet, and a second mixed liquid outlet. The second reduced iron mud inlet is connected to the second reduced iron mud outlet of the iron reduction unit 1, the water phase inlet is connected to the water phase outlet of the dehydration unit 3, and the second mixed liquid outlet is connected to the second mixed liquid inlet of the bioleaching unit 2.

[0062] Specifically, the iron reduction unit 1 may include a microbial fuel cell and / or an iron reduction reactor, and the Fenton iron sludge device may further include an air aerator 6 connected to the bioleaching unit.

[0063] In addition, the iron reduction unit may also include a Fenton iron sludge inlet.

[0064] In a specific implementation, Fenton iron mud a enters the iron reduction unit 1 from the Fenton iron mud inlet of the iron reduction unit 1, and is reduced in the iron reduction unit 1 to obtain reduced iron mud. The first reduced iron mud b1 is output from the first reduced iron mud outlet of the iron reduction unit 1, enters the bioleaching unit 2 through the first reduced iron mud inlet of the bioleaching unit 2, and obtains the first mixed liquid c after the first reduced iron mud b1 is bioleached in the bioleaching unit 2. The first mixed liquid c is output through the first mixed liquid outlet of the bioleaching unit 2, enters the dehydration unit 3 through the first mixed liquid inlet of the dehydration unit 3, and is dehydrated by the dehydration unit 3. After treatment, an aqueous phase d and a dehydrated sludge f are obtained. The aqueous phase d is output through the aqueous phase outlet of the dehydration unit 3, and enters the bypass ferrous dissolution unit 4 through the aqueous phase inlet of the bypass ferrous dissolution unit 4 after passing through the reflux unit 5. At the same time, the second reduced iron mud b2 in the iron reduction unit 1 enters the bypass ferrous dissolution unit 4 through the second reduced iron mud outlet of the iron reduction unit 1 and mixes with the aqueous phase d in the bypass ferrous dissolution unit 4 to obtain a second mixed liquid e. The second mixed liquid e leaves through the second mixed liquid outlet of the bypass ferrous dissolution unit 4, enters the bioleaching unit 2 through the second mixed liquid inlet of the bioleaching unit 2, and participates in the bioleaching treatment.

[0065] In the above treatment process, the aqueous phase produced by Fenton iron sludge a after passing through the dehydration unit 3 is refluxed to the bypass ferrous dissolution unit 4, which promotes the existence of divalent iron in a free state. This process can not only recycle the strongly acidic aqueous phase d, but also avoid the additional addition of chemical agents such as sulfuric acid, nitric acid, hydrochloric acid, and acetic acid. In addition, the iron reduction unit 1 reduces the trivalent iron in the Fenton iron sludge a to divalent iron, and uses the dissolved divalent iron as a specific microbial energy substrate for the sludge bioleaching unit 2, which can realize the resource utilization of Fenton sludge and reduce the energy substrate cost of sludge bioleaching.

[0066] In the embodiment of the present invention, after the dewatered sludge f is discharged through the dewatered sludge outlet of the dehydration unit 3, it can be post-processed according to conventional methods in the art, such as incineration, land utilization, composting, etc.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A Fenton iron sludge treatment method, characterized in that: The following steps are involved: The Fenton iron mud enters the iron reduction unit and is reduced under the action of dissimilatory iron-reducing bacteria, wherein the trivalent iron in the Fenton iron mud is reduced to divalent iron through the reduction treatment to obtain reduced iron mud; Allowing at least a portion of the reduced iron sludge to enter a bioleaching unit and undergo bioleaching treatment under the action of specific microorganisms to obtain a first mixed liquid; Dehydrating the first mixed liquid to obtain a water phase and dehydrated sludge; The water phase is returned to the bioleaching unit to participate in the bioleaching process.

2. The Fenton iron sludge treatment method according to claim 1, characterized in that: The iron reduction unit comprises a microbial fuel cell, wherein the microbial fuel cell comprises a bioanode chamber, a biocathode chamber, and a proton exchange membrane disposed between the bioanode chamber and the biocathode chamber; The bioanode chamber is provided with a bioanode material, and the bioanode material is inoculated with the dissimilatory iron-reducing bacteria; The biological cathode chamber contains oxygen; The Fenton iron mud enters the bioanode chamber for the reduction treatment; The reduction treatment time is 6 to 12 hours.

3. The Fenton iron sludge treatment method according to claim 1, characterized in that: The iron reduction unit comprises an iron reduction reactor, and the Fenton iron mud enters the iron reduction reactor for the reduction treatment; wherein the conditions for the reduction treatment are: temperature of 25°C to 35°C, pH of 6.5 to 7.5, and residence time of 12 to 24 hours.

4. The Fenton iron sludge treatment method according to claim 1, characterized in that: The specific microorganisms include acidithiobacillus; the acidithiobacillus includes ferrooxidans and / or thiooxidans.

5. The Fenton iron mud treatment method according to claim 1 or 4, characterized in that: Before the bioleaching treatment, a bacterial solution containing the specific microorganism is inoculated in the bioleaching unit, the bioleaching unit contains sludge for inoculation of the specific microorganism, and the cell density of the specific microorganism in the bacterial solution is 10 7 ~10 8 / mL, and in terms of volume ratio, the volume of the bacterial liquid accounts for 5% to 20% of the sum of the volume of the bacterial liquid and the volume of the sludge that can be used for inoculation of the specific microorganisms.

6. The Fenton iron mud treatment method according to claim 1 or 4, characterized in that: The temperature of the bioleaching treatment is 25°C to 35°C; And / or, during the bioleaching process, the residence time of the reduced iron sludge is 40 to 60 hours; and / or, during the bioleaching treatment, the reduced iron mud entering the bioleaching unit is aerated by an air aerator connected to the bioleaching unit; and / or, the pH of the first mixed liquid is 2 to 3; and / or, the dissolved oxygen of the first mixed liquid in the bioleaching unit is 3-6 mg / L; And / or, the bioleaching unit comprises nutrients for providing nutrition for the specific microorganisms, the nutrients comprising an iron source and / or a sulfur source, the iron source comprising FeSO4 and / or FeCl2, the sulfur source comprising S and / or Na2S2O3.

7. The Fenton iron sludge treatment method according to claim 1, characterized in that: The first mixed liquid is dehydrated by using a plate filter press and / or a belt filter press.

8. The Fenton iron sludge treatment method according to claim 1, characterized in that: The process of returning the water phase to the bioleaching unit to participate in the bioleaching treatment comprises: Mixing the aqueous phase with a portion of the reduced iron mud to obtain a second mixed liquid; The second mixed liquid is allowed to enter the bioleaching unit to participate in the bioleaching treatment.

9. A Fenton iron sludge treatment device, used for implementing the Fenton iron sludge treatment method according to any one of claims 1 to 8, characterized in that: The Fenton iron mud treatment device comprises: An iron reduction unit is used to perform the reduction treatment; the iron reduction unit comprises a first reduced iron mud outlet and a second reduced iron mud outlet; A bioleaching unit, used for performing the bioleaching treatment; the bioleaching unit comprises a first reduced iron mud inlet, a first mixed liquid outlet and a second mixed liquid inlet, the first reduced iron mud inlet is connected to the first reduced iron mud outlet of the iron reduction unit; A dehydration unit, used for performing the dehydration treatment; the dehydration unit comprises a first mixed liquid inlet and a water phase outlet, the first mixed liquid inlet is connected to the first mixed liquid outlet of the bioleaching unit; The bypass ferrous dissolution unit comprises a second reduced iron mud inlet, a water phase inlet, and a second mixed liquid outlet, wherein the second reduced iron mud inlet is connected to the second reduced iron mud outlet of the iron reduction unit, the water phase inlet is connected to the water phase outlet of the dehydration unit, and the second mixed liquid outlet is connected to the second mixed liquid inlet of the bioleaching unit.

10. The Fenton iron sludge treatment device according to claim 9, characterized in that: The iron reduction unit includes a microbial fuel cell and / or an iron reduction reactor; And / or, the Fenton iron mud device further comprises an air aerator connected to the bioleaching unit.

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