Biomineralization contact oxidation reactor as well as preparation method and application thereof

Abstract

The invention provides a biomineralization contact oxidation reactor and a preparation method and application thereof, the reactor is filled with a solid particle filter material as a filter layer, and the surfaces of the filter material at two ends of the filter layer are loaded with iron-oxidizing flora and iron oxyhydroxide minerals. The iron oxyhydroxide mineral has a self-catalyst function, and ferrous iron in water can be oxidized into a new iron oxyhydroxide mineral when making contact with the mineral. The invention provides an underground water arsenic removal system based on continuity of a ferrous oxidation precipitation process in a biomineralization contact oxidation reactor, and arsenic removal is realized by utilizing a coprecipitation effect and high adsorption capacity to arsenic when iron oxyhydroxide minerals are continuously formed in the system. Compared with a conventional adsorption-method arsenic removal system, the system has the advantages that the inherent limitation that a filter material needs to be updated during adsorption saturation is avoided, the energy consumption is low, the process is simple, and long-term and stable arsenic removal of underground water can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment, and in particular relates to a biomineralization contact oxidation reactor and a preparation method and application thereof. Background Art

[0002] According to my country's current "Standard for Drinking Water Quality" (GB 5749-2022), the maximum allowable concentration of arsenic in drinking water is strictly limited to 10 μg / L. Exceeding this limit can cause a range of health problems. This is especially true in reduced, high-arsenic groundwater, where arsenic primarily exists in its trivalent form. Trivalent arsenic is not only highly toxic but also difficult to remove.

[0003] At present, adsorption technology is the most widely used in groundwater arsenic removal. Its principle is to fix arsenic in water on the adsorbent through physical adsorption or chemical adsorption with the help of active sites on the adsorbent surface. For example, Chinese invention patent publication number CN119771347A discloses a preparation method of a tourmaline / zeolite composite material and its application in removing reducing toxic ions in water; Chinese invention patent publication number CN106902773A discloses a new type of oxidized resin-based nanocomposite material and its preparation method, regeneration method and application. These adsorbent materials have a good removal effect on trivalent arsenic, but as the adsorption time increases, the adsorbent will inevitably encounter adsorption saturation problems, and the adsorbent needs to be frequently regenerated or replaced, which not only increases the complexity of the operation but also increases the cost of water treatment.

[0004] In summary, solving the inherent limitations brought about by the adsorption saturation problem in the adsorption process is of great practical significance for improving the efficiency of arsenic removal from groundwater and solving the problem of arsenic pollution in groundwater. Summary of the Invention

[0005] 1. Problem to be solved

[0006] The present invention addresses one of the technical issues of adsorption arsenic removal technology in groundwater, namely the inherent limitations of adsorption saturation or low arsenic removal efficiency, and provides a biomineralization contact oxidation reactor. During the filter layer cultivation of the reactor, iron-oxidizing bacteria are first loaded onto the filter media surface, and then arsenic-containing groundwater is introduced in an alternating upflow and downflow manner to coat the filter media surfaces at both ends of the filter layer with ferric oxyhydroxide minerals. Because the ferric oxyhydroxide minerals have a self-catalytic function, when ferrous iron in the water contacts the minerals, they are immediately oxidized to form new ferric oxyhydroxide minerals. The present invention utilizes the above-mentioned biomineralization and contact oxidation to achieve the continuity of ferrous iron oxide precipitation in the reactor, and further utilizes the co-precipitation effect during the formation of the ferric oxyhydroxide minerals and their high adsorption capacity for arsenic to achieve efficient and continuous arsenic removal.

[0007] 2. Technical solution

[0008] In order to solve the above problems, the technical solutions adopted by the present invention are as follows:

[0009] The present invention provides a biomineralization contact oxidation reactor, comprising a continuous flow reactor, the continuous flow reactor comprising a first opening and a second opening, a filter layer being arranged in the continuous flow reactor; the filter layer comprising solid particle filter material; the solid particle filter material at 1 / 10 to 1 / 2 of the length at both ends of the filter layer is loaded with iron-oxidizing bacteria and iron oxyhydroxide minerals.

[0010] Furthermore, the length of the filter layer is 1 / 5 to 2 / 3 of the height of the continuous flow reactor.

[0011] Furthermore, the height of the continuous flow reactor is 100 to 150 cm. Still further, the height of the continuous flow reactor is 135 cm.

[0012] Furthermore, the diameter of the continuous flow reactor is 5 to 10 cm. Still further, the diameter of the continuous flow reactor is 6 cm.

[0013] Furthermore, the continuous flow reactor has a height-to-diameter ratio of 10-30.

[0014] Furthermore, the length of the filter layer is 20 to 100 cm. Furthermore, the length of the filter layer is 50 cm.

[0015] Furthermore, the solid particle filter material includes any one or more of quartz sand, manganese sand, and anthracite.

[0016] Furthermore, the above-mentioned solid particle filter material is manganese sand.

[0017] Furthermore, the particle size of the solid particle filter material is 0.6 to 2 mm.

[0018] Furthermore, the above-mentioned iron-oxidizing bacteria include any one or more of Arthrobacter W1, Agrobacterium W2 and Delftia J, wherein: Arthrobacter W1 is deposited in the General Microbiology Center of China Culture Collection Administration Committee of Microorganisms (CGMCC), with a deposit date of August 16, 2024, and a deposit number of CGMCCNO.31596; Agrobacterium W2 is deposited in the General Microbiology Center of China Culture Collection Administration Committee of Microorganisms (CGMCC), with a deposit date of August 16, 2024, and a deposit number of CGMCCNO.31597; Delftia J is deposited in the General Microbiology Center of China Culture Collection Administration Committee of Microorganisms (CGMCC), with a deposit date of August 16, 2024, and a deposit number of CGMCCNO.31598.

[0019] Furthermore, the iron-oxidizing bacteria are Arthrobacter W1.

[0020] The present invention also provides a method for preparing the above-mentioned biomineralization contact oxidation reactor, which comprises the following steps:

[0021] S1, filter material filling: filling the continuous flow reactor with solid particle filter material;

[0022] S2, iron-oxidizing bacteria loading: solid particulate filter material is soaked in a culture solution containing iron-oxidizing bacteria, the culture solution comprising iron-oxidizing bacteria and a culture medium for culturing the iron-oxidizing bacteria; after soaking, the culture medium is diluted with arsenic-containing groundwater oxygenated by waterfalls and introduced into a continuous flow reactor in batches, and circulated culture is carried out at a certain flow rate, the dilution ratio of the culture medium introduced in batches is gradually increased to gradually reduce the content of nutrients in the culture medium, and at least the last batch is introduced with arsenic-containing groundwater oxygenated by waterfalls (without culture medium); as a further explanation of the present invention, the purpose of the circulated culture is to load the iron-oxidizing bacteria, and the purpose of gradually reducing the content of nutrients in the culture medium is to acclimate the iron-oxidizing bacteria loaded on the surface of the filter material so that it can gradually adapt to the water quality characteristics of the groundwater;

[0023] S3, maturation: the arsenic-containing groundwater after the waterfall oxygenation is passed into a continuous flow reactor at a certain flow rate in an alternating upflow and downflow manner to mature the filter material, thereby obtaining a biomineralization contact oxidation reactor; as a further explanation of the present invention, the purpose of selecting arsenic-containing groundwater is to simultaneously utilize the native ferrous iron and its natural microbial community in the groundwater, thereby accelerating the maturation of the filter material (coating of hydroxyl iron minerals) and the development of the surface microbial community; the purpose of adopting the alternating upflow and downflow water inflow method is to make the filter materials at both ends of the filter layer continuously covered with new ecological hydroxyl iron minerals with self-catalytic function, compared with the conventional unidirectional water inflow method in which hydroxyl iron minerals are only formed on the filter material at one end of the filter layer, the contact time between arsenic and new ecological hydroxyl iron minerals can be effectively prolonged, which is more conducive to the removal of arsenic.

[0024] Furthermore, the ferrous iron concentration in the above-mentioned arsenic-containing groundwater is ≥4 mg / L; as a further illustration of the present invention, in order to ensure the continuity of the ferrous iron oxidation precipitation process, that is, to be able to continuously generate new ecological ferric oxyhydroxide minerals for arsenic removal, when the native ferrous iron concentration in the groundwater is lower than 4 mg / L, the ferrous iron concentration needs to be increased by exogenous addition.

[0025] Furthermore, the soaking time is 24 to 72 hours. Still further, the soaking time is 48 hours.

[0026] Furthermore, the culture medium diluted with arsenic-containing groundwater oxygenated by waterfall is introduced in batches for 5 to 10 batches, and the culture time for each batch is 5 to 7 days. Furthermore, the culture medium diluted with arsenic-containing groundwater oxygenated by waterfall is introduced in batches for 7 batches, and the culture time for each batch is 7 days.

[0027] Furthermore, the diluted culture medium introduced in batches includes at least diluted culture medium with a ratio of arsenic-containing groundwater oxygenated by waterfall to culture medium of 2:8, 4:6, 6:4, 8:2 and 10:0.

[0028] Furthermore, the above-mentioned culture medium components are: 10g / L ammonium ferric citrate, 2g / L MnSO4·H2O, 0.5g / L K2HPO4, 0.5g / L NaNO3, 0.5g / L CaCl2, 0.5g / L MgSO4·7H2O, and 0.1g / L NaCl.

[0029] Furthermore, the flow rate in the circulation culture is 0.2 to 5 m / h. Still further, the flow rate in the circulation culture is 0.2 m / h.

[0030] Furthermore, the flow rate during the aging is 0.5 to 5 m / h. Furthermore, the flow rate during the aging is 2 m / h.

[0031] Furthermore, the alternating cycle of the upflow and downflow is 0.5 to 7 days, and the flow rate is 0.5 to 5 m / h. Furthermore, the alternating cycle of the upflow and downflow is 0.5 days, and the flow rate is 2 m / h.

[0032] Furthermore, the above-mentioned aging process also includes backwashing.

[0033] Furthermore, the backwashing cycle is 48 to 72 hours. Still further, the backwashing cycle is 60 hours.

[0034] Furthermore, the backwash intensity is 10 to 18 L / (s·m 2 Furthermore, the backwash intensity is 10L / (s·m 2 ).

[0035] Furthermore, the backwashing time is 5 to 10 minutes. Still further, the backwashing time is 5 minutes.

[0036] Furthermore, the aging time is 12 to 78 days. Still further, the aging time is 18 days.

[0037] The present invention also provides a groundwater arsenic removal system, which comprises the above-mentioned biomineralization contact oxidation reactor.

[0038] Furthermore, the above-mentioned groundwater arsenic removal system also includes a water collection tank, a waterfall oxygenation zone and an outlet water collection tank, and the water collection tank, the waterfall oxygenation zone, the biomineralization contact oxidation reactor and the outlet water collection tank are connected in sequence; wherein: the first opening and the second opening of the biomineralization contact oxidation reactor are selectively connected to the waterfall oxygenation zone and the outlet water collection tank: when the waterfall oxygenation zone is connected to the first opening of the biomineralization contact oxidation reactor, the second opening is connected to the outlet water collection tank; when the waterfall oxygenation zone is connected to the second opening of the biomineralization contact oxidation reactor, the first opening is connected to the outlet water collection tank; as a further explanation of the present invention, the above-mentioned openings are designed to realize the groundwater arsenic removal system to have water inlet in an alternating upflow and downflow manner during actual operation.

[0039] Furthermore, the height of the waterfall in the above-mentioned waterfall oxygenation zone is 50 to 100 cm, and the ferrous iron in the groundwater after the waterfall oxygenation should not be oxidized before entering the ferrous iron biomineralization contact oxidation arsenic removal reactor.

[0040] Furthermore, the height of the water drop in the above-mentioned water drop oxygenation zone is 60 cm.

[0041] The present invention also provides the application of the above-mentioned biomineralization contact oxidation reactor or the above-mentioned groundwater arsenic removal system in groundwater arsenic removal. In the present invention, since arsenic-containing groundwater is usually accompanied by a certain concentration of ferrous iron, ferrous iron contacts the iron-oxidizing bacteria community and is oxidized to trivalent iron ions, and further hydrolyzed and precipitated to form ferric hydroxide minerals. The coprecipitation effect during the formation of the mineral and its own adsorption performance for arsenic can achieve the removal of arsenic. At the same time, the ferric hydroxide mineral itself has a good catalytic oxidation effect (self-catalytic function) on ferrous iron, that is, in the presence of oxygen, ferrous iron contacts the mineral and is immediately oxidized and precipitated into a new ecological ferric hydroxide mineral, which ensures the continuity of the ferrous oxide precipitation process, thereby maintaining the continuous production of ferric hydroxide minerals to achieve long-term and stable arsenic removal.

[0042] The present invention also provides a method for removing arsenic from groundwater, which is carried out using the above-mentioned groundwater arsenic removal system. After the groundwater in the collection tank is oxygenated in the waterfall oxygenation zone, it is passed into a biomineralization contact oxidation reactor in an alternating upflow and downflow manner at a certain flow rate. Under the synergistic effect of the biomineralization of the iron-oxidizing bacteria and the contact oxidation of oxyhydroxide iron minerals, the ferrous iron in the groundwater will be rapidly oxidized to generate new oxyhydroxide iron minerals. The purpose of arsenic removal is achieved by utilizing the co-precipitation effect of the mineral during its formation and its high adsorption capacity for arsenic, and the effluent enters the effluent collection tank.

[0043] Furthermore, the alternating cycle of the upflow and downflow is 0.5 to 7 days, and the flow rate is 2 to 9 m / h.

[0044] Furthermore, the alternating cycle of the upflow and downflow is 0.5 days, and the flow rate is 2 m / h.

[0045] Furthermore, the above arsenic removal method also includes a backwashing step.

[0046] Furthermore, the backwashing cycle is 48 to 72 hours. Still further, the backwashing cycle is 72 hours.

[0047] Furthermore, the backwash intensity is 10 to 18 L / (s·m 2 Furthermore, the backwash intensity is 12L / (s·m 2 ).

[0048] Furthermore, the backwashing time is 5 to 10 minutes. Still further, the backwashing time is 5 minutes.

[0049] 3. Beneficial effects

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] (1) The present invention provides a biomineralization contact oxidation reactor and its preparation method and application. The reactor is provided with a filter layer of solid particle filter material. The filter material surfaces at both ends of the filter layer are loaded with iron-oxidizing bacteria and ferric oxyhydroxide minerals. The ferric oxyhydroxide minerals have a self-catalytic function. When ferrous iron in groundwater contacts the minerals, it will be immediately oxidized into new ferric oxyhydroxide minerals, ensuring the continuity of the ferrous iron oxidation precipitation process. The present invention utilizes the co-precipitation effect of the continuous formation of ferric oxyhydroxide minerals and their high adsorption capacity for arsenic to achieve the purpose of arsenic removal. The co-precipitation effect can alleviate the defect of rapid adsorption saturation, circumventing the inherent limitation of traditional adsorbents that require frequent renewal of filter material for adsorption saturation, and reducing the cost and operational difficulty of treating arsenic-containing groundwater.

[0052] (2) The present invention provides a biomineralization contact oxidation reactor and its preparation method and application. The reactor is operated by alternating upflow and downflow water inflow, so that the filter materials at both ends of the filter layer are continuously covered with new ecological hydroxyl iron minerals with self-catalytic function. Compared with the conventional one-way water inflow method in which minerals are formed only on the filter material at one end of the filter layer, the alternating water inflow mode can effectively prolong the contact time between arsenic and the new ecological hydroxyl iron minerals in the reactor, which is more conducive to the removal of arsenic.

[0053] (3) The present invention provides a biomineralization contact oxidation reactor, its preparation method, and its application. The reactor has the dual iron removal functions of biomineralization and contact oxidation of ferric oxyhydroxide minerals. It has been verified that ferrous iron in groundwater is completely oxidized and removed within the first 15 cm of the filter layer at both ends. In actual groundwater arsenic removal treatment, its operation time is as long as 30 days, and it can still ensure the complete oxidation of ferrous iron, providing a guarantee for the continuous and efficient removal of arsenic in groundwater. The treated water meets the current "National Drinking Water Hygiene Standard" (GB 5749-2022) in my country.

[0054] (4) The present invention provides a biomineralization contact oxidation arsenic removal reactor, its preparation method, and its application. The filter layer cultivation process in the reactor is simple and low-cost, and the arsenic removal system it constitutes has significant and stable arsenic removal effects. Furthermore, the system generates no additional pollutants during operation, making it very environmentally friendly. This is a highly efficient, economical, and environmentally friendly method for groundwater arsenic removal, with broad application prospects and significant practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 1 is an appearance diagram of the filter material at the upper and lower ends of the filter layer in the biomineralization contact oxidation reactor after aging for 18 days in the present invention, wherein: (a) is the filter material at the upper end of the filter layer, and (b) is the filter material at the lower end of the filter layer.

[0056] Figure 2 This is the result of removing ferrous iron in the biomineralization contact oxidation reactor of the present invention at different water inlet directions.

[0057] Figure 3 It is a schematic diagram of the groundwater arsenic removal system of the present invention.

[0058] Figure 4 This is the result of arsenic removal by the biomineralization contact oxidation reactor of the present invention at different water inlet directions.

[0059] Figure 5 The results of the ferrous and arsenic removal in groundwater by the groundwater arsenic removal system of the present invention within 30 days of operation are shown in FIG. 1 , wherein: (a) is the concentration of ferrous iron in the effluent, and (b) is the concentration of arsenic in the effluent. DETAILED DESCRIPTION

[0060] The present invention will be further described below with reference to specific embodiments.

[0061] It should be noted that the terms such as "upper", "lower", "left", "right", and "middle" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0062] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0063] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0064] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement, or value. One skilled in the art can readily determine the degree of flexibility for a particular variable.

[0065] As used herein, the term "at least one of" is intended to be synonymous with "one or more of." For example, "at least one of A, B, and C" explicitly includes only A, only B, only C, and combinations of each thereof.

[0066] Concentration, amount and other numerical data can be presented in range format in this article.Should be understood that such range format is only used for convenience and brevity, and should be flexibly interpreted as not only including the numerical value clearly described as range limit, but also including all independent numerical values ​​or subranges encompassed within the scope, just as each numerical value and subrange are clearly described.For example, the numerical range of about 1 to about 4.5 should be interpreted as not only including the limit value of 1 to about 4.5 clearly described, but also including independent numerals (such as 2,3,4) and subranges (such as 1 to 3,2 to 4 etc.).The same principle is applicable to the scope of only narrating a numerical value, such as "less than about 4.5", which should be interpreted as including all above-mentioned values ​​and scopes.In addition, no matter how the breadth of described scope or feature is, this explanation should be applicable.

[0067] Example 1

[0068] This embodiment provides a biomineralization contact oxidation reactor and a preparation method thereof.

[0069] The biomineralization contact oxidation reactor includes a continuous flow reactor, which includes a first opening and a second opening. A filter layer is arranged in the continuous flow reactor; the filter layer includes solid particle filter material, and the length of the filter layer is 1 / 5 to 2 / 3 of the height of the continuous flow reactor; the solid particle filter material of 1 / 10 to 1 / 2 of the length at both ends of the filter layer is loaded with iron-oxidizing bacteria and iron oxyhydroxide minerals.

[0070] In this embodiment,

[0071] The continuous flow reactor is a cylindrical continuous flow reactor with a diameter of 6 cm and a height of 135 cm, and is provided with a first opening and a second opening;

[0072] The solid particle filter material is manganese sand particles with a particle size of 0.6 to 2 mm; the filling thickness of the manganese sand particles is 50 cm;

[0073] The iron-oxidizing bacterium is Arthrobacter W1, which was deposited in the General Microbiology Center of the China Culture Collection Administration of Microorganisms (CGMCC) on August 16, 2024, with the deposit number CGMCC NO.31596.

[0074] The preparation method comprises the following steps:

[0075] S1, filter material filling: filling the continuous flow reactor with solid particle filter material;

[0076] S2, iron-oxidizing bacteria loading: solid particulate filter material is soaked in a culture solution containing iron-oxidizing bacteria, the culture solution including the iron-oxidizing bacteria and a culture medium for culturing the iron-oxidizing bacteria; after soaking, the culture medium is diluted with arsenic-containing groundwater that has been oxygenated by waterfalls and introduced into a continuous flow reactor in batches, and circulated at a constant flow rate. The dilution ratio of the diluted culture medium introduced in batches is gradually increased to gradually reduce the content of nutrients in the culture medium, and at least the last batch is introduced with arsenic-containing groundwater that has been oxygenated by waterfalls;

[0077] S3, maturation: the arsenic-containing groundwater after the waterfall oxygenation is passed into the tubular continuous flow at a certain flow rate in an alternating upflow and downflow manner to mature the filter material, thereby obtaining a biomineralization contact oxidation arsenic removal reactor.

[0078] In this embodiment, it specifically includes:

[0079] S1, filter material filling: a cylindrical continuous flow reactor with a diameter of 6 cm and a height of 135 cm was filled with manganese sand particles with a thickness of 50 cm. In this embodiment, to facilitate subsequent testing, a water inlet was set on the reactor at intervals of 10 cm, starting from 5 cm below the top of the filter material.

[0080] S2, iron-oxidizing bacteria load: using a culture medium containing the iron-oxidizing bacteria Arthrobacter W1 (OD 600=0.6) for 48 hours of soaking the solid particle filter material; introducing a culture medium diluted with arsenic-containing groundwater oxygenated by a waterfall into a continuous flow reactor in 7 batches and circulating the culture at a flow rate of 0.2 m / h, specifically: introducing arsenic-containing groundwater oxygenated by a 60 cm waterfall (Fe(II) concentration of about 5.5 mg / L, As concentration of about 140 μg / L) to the culture medium in a volume ratio of 0:10, 2:8, 4:6, 6:4, 8:2, 9:1 and 10:0, for a total of 7 batches, and each batch was cultured for 7 days; wherein the culture medium containing the iron-oxidizing bacteria contains the following components: 10 g / L ammonium ferric citrate, 2 g / L MnSO4·H2O, 0.5 g / L K2HPO4, 0.5 g / L NaNO3, 0.5 g / L CaCl2, 0.5 g / L MgSO4·7H2O, and 0.1 g / L NaCl;

[0081] S3, after the maturation cycle, the arsenic-containing groundwater, which had been oxygenated by a 60 cm waterfall, was introduced into the continuous flow reactor in an alternating pattern of 0.5-day upflow and 0.5-day downflow, with a flow rate of 2 m / h and a flow rate of 10 L / (s·m) every 60 h. 2 ) intensity for 5 minutes to backwash the filter layer. After 18 days of maturation, a biomineralization contact oxidation reactor was obtained. The filter media at different depths in the filter layer were observed. The results are as follows: Figure 1 As shown, it can be seen that the surface color of the filter material in the area 15 cm before the upper end of the filter layer and 15 cm before the lower end of the filter layer changes from the initial brown-yellow to reddish-brown, that is, the surface is covered with new ecological iron oxyhydroxide minerals and a stable microbial community is formed, indicating that the biomineralization contact oxidation reactor was successfully prepared.

[0082] In this embodiment, the effluent from the filter layers of different depths after aging for 18 days was sampled through the water intake of the continuous flow reactor, and the ferrous content of the effluent was detected by o-phenanthroline spectrophotometry (HJ / T 345-2007). The results are as follows: Figure 2 As shown, it can be seen that the ferrous iron in the groundwater was completely oxidized and removed in the first 15 cm filter layer with different water inlet directions, suggesting that the reactor can quickly and fully oxidize and precipitate the ferrous iron in the groundwater into ferric oxyhydroxide minerals through the synergistic effect of biomineralization and contact oxidation of ferric oxyhydroxide minerals.

[0083] Example 2

[0084] This embodiment provides a groundwater arsenic removal system.

[0085] The arsenic removal system includes the biomineral contact oxidation reactor in Example 1, specifically as follows Figure 3As shown, it includes a water collection tank, a waterfall oxygenation area, a biomineralization contact oxidation reactor and an effluent collection tank in sequence.

[0086] In which: in order to realize the alternating upflow and downflow water inlet mode during the actual operation of the arsenic removal system, the first opening and the second opening of the biomineralization contact oxidation reactor can be selectively connected to the waterfall oxygenation zone and the effluent collection pool: when the waterfall oxygenation zone is connected to the first opening of the biomineralization contact oxidation reactor, the second opening is connected to the effluent collection pool; when the waterfall oxygenation zone is connected to the second opening of the biomineralization contact oxidation reactor, the first opening is connected to the effluent collection pool.

[0087] Example 3

[0088] This embodiment provides a method for removing arsenic from groundwater.

[0089] The method uses the groundwater arsenic removal system in Example 2 to treat arsenic-containing groundwater, and the water quality components of the groundwater are the same as those in Example 1.

[0090] Specifically, the groundwater in the water collection tank is oxygenated by a 60cm waterfall in the waterfall oxygenation zone, and then enters the biomineralization contact oxidation reactor in an alternating manner of 0.5d upflow and 0.5d downflow, with a flow rate of 2m / h. Under the synergistic effect of iron-oxidizing bacteria biomineralization and oxyhydroxide iron mineral contact oxidation, the ferrous iron in the groundwater is rapidly oxidized to form new oxyhydroxide iron minerals, which are used to remove arsenic by co-precipitation and high adsorption capacity for arsenic. The treated effluent enters the effluent collection tank. During the above treatment process, the water is heated at a rate of 12L / (s·m 2 The filter layer was backwashed with tap water for 5 minutes at a specific intensity, for a total treatment duration of 6 days. Simultaneously, effluent from filter layers at different depths was sampled through the reactor's intake port and analyzed for arsenic concentration using an inductively coupled plasma mass spectrometer.

[0091] Result analysis:

[0092] The results are as follows Figure 4 As shown in the figure, arsenic in groundwater was rapidly removed in the first 15 cm of the groundwater using different inlet directions (0-15 cm of filter layer depth for downflow filtration and 35-50 cm of filter layer depth for upflow filtration), reducing the initial concentration from 140 μg / L to approximately 17 μg / L. Subsequently, arsenic was further removed in the outlet direction (35-50 cm of filter layer depth for downflow filtration and 0-15 cm of filter layer depth for upflow filtration), relying on the high adsorption capacity of nascent iron oxyhydroxide minerals for arsenic. The final arsenic concentration dropped to below 10 μg / L, meeting my country's current "Standards for Drinking Water Quality" (GB 5749-2022).

[0093] Example 4

[0094] This example provides an arsenic removal stability test of a groundwater arsenic removal system.

[0095] The groundwater arsenic removal method described in Example 3 was used to treat groundwater with the same water quality and composition, using the same treatment conditions as in Example 3. To test the stability of the system's arsenic removal, the system was operated continuously for 30 days. The effluent was collected from the effluent collection tank at different time intervals, and the ferrous and arsenic contents were measured. The ferrous content was measured using the same method as in Example 1, and the arsenic content was measured using the same method as in Example 3.

[0096] Result analysis:

[0097] The results are as follows Figure 5 As shown in the figure, the groundwater arsenic removal system maintained stable iron and arsenic removal results after 30 days of continuous operation. Ferrous iron was completely removed, with ferrous iron concentrations reaching 0 mg / L in the effluent at all time periods. Arsenic concentrations also remained below 10 μg / L, meeting my country's current "Standard for Drinking Water Quality" (GB 5749-2022).

[0098] In summary, the groundwater arsenic removal system of the present invention can achieve efficient and stable removal of arsenic in groundwater.

Claims

1. A biomineralization contact oxidation reactor, comprising a continuous flow reactor, wherein the continuous flow reactor comprises a first opening and a second opening, characterized in that: A filter layer is provided in the continuous flow reactor; the filter layer comprises solid particle filter material; and the solid particle filter material at 1 / 10 to 1 / 2 of the length at both ends of the filter layer is loaded with iron oxidizing bacteria and iron oxyhydroxide minerals.

2. The biomineralization contact oxidation reactor according to claim 1, characterized in that: The length of the filter layer is 1 / 5 to 2 / 3 of the height of the continuous flow reactor; and / or The solid particle filter material includes any one or more of quartz sand, manganese sand, and anthracite; the particle size is 0.6 to 2 mm; the filling thickness is 50 to 150 cm; and / or The iron-oxidizing bacteria include any one or more of Arthrobacter W1, Agrobacterium W2, and Delftia J; wherein: Arthrobacter W1 is deposited in the General Microbiology Center of the China Culture Collection Administration Committee of Microorganisms (CGMCC), with a deposit date of August 16, 2024, and a deposit number of CGMCC NO.31596; Agrobacterium W2 is deposited in the General Microbiology Center of the China Culture Collection Administration Committee of Microorganisms (CGMCC), with a deposit date of August 16, 2024, and a deposit number of CGMCC NO.31597; Delftia J is deposited in the General Microbiology Center of the China Culture Collection Administration Committee of Microorganisms (CGMCC), with a deposit date of August 16, 2024, and a deposit number of CGMCC NO.31598.

3. The method for preparing the biomineralization contact oxidation reactor according to claim 1 or 2, characterized in that: The method comprises the following steps: S1, filter material filling: filling the continuous flow reactor with solid particle filter material; S2, iron-oxidizing bacteria loading: soaking the solid particulate filter material in a culture solution containing iron-oxidizing bacteria, wherein the culture solution includes the iron-oxidizing bacteria and a culture medium for culturing the iron-oxidizing bacteria; after soaking, the culture medium is diluted with arsenic-containing groundwater oxygenated by waterfall and introduced into a continuous flow reactor in batches, and the culture is circulated at a constant flow rate, with the dilution ratio of the culture medium introduced in batches gradually increasing, and at least the last batch is introduced with arsenic-containing groundwater oxygenated by waterfall; S3, maturation: the arsenic-containing groundwater after the waterfall oxygenation is passed into a continuous flow reactor in an alternating upflow and downflow manner at a certain flow rate to mature the filter material, thereby obtaining a biomineralization contact oxidation reactor.

4. The method for preparing a biomineralization contact oxidation reactor according to claim 3, characterized in that: The ferrous iron concentration in the arsenic-containing groundwater is ≥4 mg / L.

5. The method for preparing a biomineralization contact oxidation reactor according to claim 3 or 4, characterized in that: The solid particle filter material is soaked in the culture solution containing the iron oxidizing bacteria for 24 to 72 hours; and / or The culture medium diluted with arsenic-containing groundwater oxygenated by waterfall is introduced in batches, including 5 to 10 batches, and the culture time of each batch is 5 to 7 days; and / or The flow rate of the circulation culture is 0.2-5 m / h; and / or The flow rate during the aging is 0.5 to 5 m / h; and / or The alternating period of the upflow and downflow is 0.5 to 7 days, and the flow rate is 0.5 to 5 m / h.

6. A groundwater arsenic removal system, characterized in that: The groundwater arsenic removal system includes the biomineralization contact oxidation reactor according to claim 1 or 2.

7. A groundwater arsenic removal system according to claim 6, characterized in that: The groundwater arsenic removal system also includes a water collection tank, a waterfall oxygenation area and an outlet water collection tank; The first opening and the second opening of the biomineralization contact oxidation reactor are selectively connected to the waterfall oxygenation zone and the effluent collection pool: when the waterfall oxygenation zone is connected to the first opening of the biomineralization contact oxidation reactor, the second opening is connected to the effluent collection pool; when the waterfall oxygenation zone is connected to the second opening of the biomineralization contact oxidation reactor, the first opening is connected to the effluent collection pool.

8. Use of the biomineralization contact oxidation reactor according to claim 1 or 2, or the groundwater arsenic removal system according to claim 6 or 7 in groundwater arsenic removal.

9. A method for removing arsenic from groundwater, characterized in that: The groundwater arsenic removal system according to claim 6 or 7 is used, and the groundwater in the collection tank is oxygenated by the waterfall in the waterfall oxygenation zone, and then passed into the biomineralization contact oxidation reactor in an alternating upflow and downflow manner at a certain flow rate, and the effluent enters the effluent collection tank.

10. The method for removing arsenic from groundwater according to claim 9, characterized in that: The alternating cycle of the upflow and downflow is 0.5 to 7 days, and the flow rate is 2 to 9 m / h.

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