Activated sludge for treating wastewater subjected to combined pollution of arsenic and butyl xanthate and preparation method of activated sludge

Abstract

The invention relates to the field of wastewater treatment, in particular to activated sludge for treating wastewater containing arsenic and butyl xanthate combined pollution and a preparation method thereof.The preparation method comprises the steps that 1, soil near lead-zinc tailings is taken as an original sample, and initial sludge is obtained; step 2, preparing a culture solution for culturing sludge; step 3, adding a culture solution into an anaerobic bottle, and then putting the initial sludge into the bottle; and 4, adding sodium arsenate and butyl xanthate into the bottle, uniformly stirring, discharging oxygen, and carrying out shake culture to obtain the domesticated and cultured anaerobic activated sludge. According to the method disclosed by the invention, the cultured activated sludge has unique biological characteristics through collection and domestication steps at a specific site, arsenic reduction can be carried out under the condition of not additionally adding an organic carbon source, xanthate can be effectively oxidized and removed, and the yield of the activated sludge is increased. The requirements of low-cost and high-efficiency removal of arsenic and xanthate in beneficiation wastewater in an oligotrophic mining area and the like can be met.

Description

Technical Field

[0001] The present invention relates to the field of wastewater treatment, and particularly to an activated sludge for treating wastewater contaminated with arsenic and butyl xanthate and a preparation method thereof. Background Art

[0002] Arsenic (As) is a heavy (metalloid) metal element with high toxicity and is widely present in natural and anthropogenic environments. Its natural sources mainly include rock weathering, volcanic activities, and natural releases from the soil. In anthropogenic activities, arsenic mainly comes from the mining and smelting processes of non-ferrous metal deposits. For example, arsenic is often associated with non-ferrous metal deposits such as gold, copper, nickel, and cobalt. During the smelting process, arsenic will enter the soot or hydrometallurgical slag, forming arsenic-containing waste. In addition, the production process of semiconductor materials such as gallium arsenide in the electronics industry will also generate arsenic-containing wastewater. The discharge of arsenic-containing wastewater poses a serious threat to the environment and human health. Arsenic and its compounds are listed as Group 1 carcinogens by the International Agency for Research on Cancer (IARC) and have the "three carcinogenic effects" of mutagenesis, teratogenesis, and carcinogenesis. In industrial wastewater, arsenic mainly exists in the forms of trivalent arsenic (As 3+ )and pentavalent arsenic (As 5+ ). If arsenic-containing wastewater is directly discharged without treatment, it will cause water pollution, arsenic enrichment in soil, and arsenic accumulation in crops, and then threaten human health through the food chain.

[0003] In mining activities, flotation wastewater is one of the important pollution sources generated during the ore beneficiation process. Xanthate (hydrocarbyl dithiocarbonate), a commonly used collector in the flotation process, is the main harmful component of flotation wastewater. Xanthate has high toxicity, a pungent odor, and is difficult to degrade in water. A small amount can make the water stench and deteriorate. According to statistics, the annual discharge of mining wastewater in China is huge, and the discharge of ore beneficiation wastewater is particularly prominent. It is estimated that its consumption will reach about 370 million tons in 2025. A large amount of untreated wastewater is directly discharged, causing serious pollution to water bodies and the surrounding ecological environment.

[0004] In the published Chinese patents, there are few studies and reports on the simultaneous and efficient removal of butyl xanthate and heavy metal As(V) in flotation wastewater by biological methods. The research mainly focuses on the use of a single strain, and generally can only remove butyl xanthate or arsenic. There is no relevant research and report on the treatment method of the microorganisms in the activated sludge for the wastewater contaminated with arsenic and butyl xanthate.

[0005] In terms of removing butyl xanthate and heavy metals, the Shewanella oneidensis disclosed in Chinese Patent CN109574407A Shewanella oneidensisMR-1 rapidly degrades butyl xanthate in flotation wastewater under aerobic conditions; Cr(VI) is used as an electron acceptor to fix and harmlessly degrade Cr(VI) in flotation wastewater under anaerobic conditions, achieving efficient and rapid removal of butyl xanthate and heavy metal Cr(VI) in flotation wastewater. Chinese patent CN115010302A discloses a method for selectively degrading and removing some heavy metals and xanthate flotation agents with poor flotation selectivity in lead and zinc flotation wastewater by regulating the input voltage of the external electric field of the electrocatalytic internal electrolysis reactor. Chinese patent CN111018085A discloses a method for treating flotation wastewater containing xanthate and heavy metals by chemical oxidation, achieving degradation of xanthate in flotation wastewater and simultaneous deep removal of heavy metals in flotation wastewater. The acidophilic elemental sulfur-reducing bacteria disclosed in Chinese patent CN113748091A utilize organic carbon to reduce elemental sulfur to sulfide. Pentavalent arsenic is reduced to trivalent arsenic under the joint action of elemental sulfur-reducing bacteria with arsenic-reducing ability and sulfide. Trivalent arsenic and sulfide form arsenic-sulfur compound precipitation, thereby quickly and simultaneously removing trivalent arsenic and pentavalent arsenic in wastewater.

[0006] In summary, the existing treatment technologies can only remove arsenic or xanthate separately, or use a single strain or chemical oxidation method to remove xanthate and heavy metals in flotation wastewater, and the heavy metals do not include arsenic. With the acceleration of the industrialization process, the treatment of arsenic-containing wastewater and flotation wastewater containing xanthate has become an environmental problem that needs to be solved urgently. Chemical precipitation, adsorption and oxidation methods still have shortcomings in removal efficiency and economy, and may cause secondary pollution. Biological methods are an efficient, economical and environmentally friendly treatment technology. Compared with the use of a single strain, activated sludge does not require screening, separation, purification and addition of organic carbon sources, so it has important practical significance for solving the pollution problem of flotation wastewater containing arsenic and xanthate. Summary of the invention

[0007] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for treating wastewater containing arsenic and butyl xanthate composite pollution based on microorganisms in activated sludge, which can simultaneously have the biological characteristics of xanthate oxidation removal and arsenic reduction fixation without adding an organic carbon source. The present invention also provides an application of the method, which has good removal efficiency and simple operation, can meet the needs of low-cost and high-efficiency removal of arsenic and xanthate from flotation wastewater, and has good application prospects in mining or other oligotrophic environments.

[0008] The purpose of the present invention is achieved by the following technical solutions: In a first aspect, the present invention provides a method for preparing activated sludge for treating wastewater contaminated with arsenic and butyl xanthate, comprising the following steps: Step 1, taking soil near the mine tailings as an original sample to obtain initial sludge; Step 2, prepare a culture solution for culturing sludge; Step 3, add the culture solution to an anaerobic bottle, and then put the initial sludge into the bottle; Step 4, add sodium arsenate and butyl xanthate to the bottle, stir evenly, discharge oxygen, and perform oscillating cultivation to obtain domesticated anaerobic activated sludge.

[0009] Preferably, in step 1, the sample is collected by using the plum-blossom point sampling method for fixed-point sampling. Surface, middle, and deep soil are collected from the soil near the tailings discharge port of the mine into a sterile sampling bag, and stored for use after refrigerated transportation.

[0010] Preferably, in step 1, in the soil near the lead-zinc tailings, the initial microbial community includes: Pseudomonadota (Pseudomonadota) 75.77%, Bacillota (Firmicutes) 9.41%, Nitrospirota (Nitrospirota) 3.54%, Deinococcota (Deinococcota) 2.84%, Actinomycetota (Actinomycetota) 1.22%, Dependentiae (Dependoprotista) 1.01% and other microorganisms 6.21%.

[0011] Preferably, in step 2, the components in the culture solution are calculated by concentration and include: calcium chloride 0.2460 g / L, magnesium chloride 1.0572 g / L, sodium chloride 0.4459 g / L, dipotassium hydrogen phosphate 0.0299 g / L, potassium chloride 0.0283 g / L, sodium bicarbonate 0.8082 g / L, ammonium chloride 0.1557 g / L.

[0012] Preferably, in step 3, the pH is adjusted to 7.0 ± 0.1, and the initial sludge concentration is 3.0 g / L Preferably, in step 4, the concentration of sodium arsenate after addition is 0.01 - 0.03 g / L, and the concentration of butyl xanthate after addition is 0.1 - 0.3 g / L.

[0013] Preferably, in step 4, discharging oxygen is to introduce pure nitrogen into the anaerobic bottle for at least 20 min.

[0014] Preferably, in step 4, the temperature of the oscillating cultivation is 25 °C, the speed is 150 - 180 r / min, and the cultivation time is 10 - 14 d.

[0015] Preferably, in step 4, the microbial community of the anaerobic activated sludge includes: Pseudomonadota (Pseudomonadota) 90.80%, Bacteroidota (Bacteroidota) 6.14%, Dependentiae2.41% (Phylum Dependens) and 0.65% other microorganisms.

[0016] In a second aspect, the present invention provides an activated sludge for treating wastewater contaminated with arsenic and butyl xanthate, which is prepared by the above preparation method.

[0017] In a second aspect, the present invention provides an application of activated sludge in the treatment of wastewater contaminated with arsenic and butyl xanthate.

[0018] The beneficial effects of the present invention are as follows: 1. Through the collection and domestication steps at specific locations, the cultivated activated sludge has unique biological characteristics. It can not only reduce arsenic without additional addition of organic carbon sources, but also effectively oxidize and remove xanthate, meeting the requirements of low-cost and high-efficiency removal of arsenic and xanthate in ore dressing wastewater in oligotrophic mining areas.

[0019] 2. The activated sludge prepared by the method of the present invention is Pseudomonadota 90.80% (Pseudomonadota) and Bacteroidota 6.14% (Bacteroidota) as the dominant genera of activated sludge. These genera are collected and identified from tailing samples and have strong adaptability to the oligotrophic mining (arsenic-polluted) environment. Applying them to bioremediation can reduce the environmental remediation cost. And subsequently, through the screening and domestication of the dominant strains, microbial agents with specific functions can be developed for use in environmental protection, industrial production and other fields.

[0020] 3. Applying the method of the present invention to the treatment of wastewater contaminated with arsenic and butyl xanthate, under anaerobic conditions, the microorganisms in the activated sludge can oxidize butyl xanthate and use its sulfur source to reduce and immobilize arsenate; within 7 days, the removal rate of 50 mg / L butyl xanthate is 99.96%, the corresponding TOC utilization rate is 80.4%, the As(V) reduction rate is 72.93%, and the TAs removal rate is 65.26%.

[0021] 4. Applying the method of the present invention to the treatment of continuous-flow wastewater contaminated with arsenic and butyl xanthate, under anaerobic conditions, within 30 days, the removal rate of 200 mg / L butyl xanthate is 99.64%, the As(V) reduction rate is 96.13%, and the TAs removal rate is 94.70%.

[0022] 5. The method of the present invention can make better use of xanthate as an organic substrate, maintain a high removal rate of xanthate while achieving the removal of organic carbon and arsenic. Applying this method to the wastewater treatment in mining areas containing xanthate and arsenic is conducive to simplifying the wastewater treatment process, improving the treatment efficiency, meeting the requirements of environmental friendliness, and having good economic and environmental benefits. It can overcome the problem of difficult growth of organisms caused by insufficient carbon source, making the synchronous removal of xanthate and arsenic possible, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described with reference to the accompanying drawings. However, the embodiments in the drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the following drawings.

[0024] Figure 1 It is a relative abundance diagram of the microbial community composition of the original tailings sample (a) and the domesticated activated sludge (b) in Example 1 of the present invention; Figure 2 It is the removal effect diagram of the original tailings sample (before) and the domesticated activated sludge (after) obtained after 14 days of domestication in Example 1 of the present invention for the wastewater containing butyl xanthate (A 301 ) and arsenic; Figure 3 It is the removal effect diagram of the tailings sample in Example 2 of the present invention for the wastewater containing butyl xanthate and arsenic with respect to butyl xanthate (BX) and total organic carbon (TOC) under anaerobic conditions; Figure 4 It is the removal effect diagram of the tailings sample in Example 2 of the present invention for the wastewater containing butyl xanthate and arsenic with respect to arsenic under anaerobic conditions; Figure 5 It is the removal rate effect diagram of the tailings sample in Example 2 of the present invention for the wastewater containing butyl xanthate and arsenic under anaerobic conditions; Figure 6 It is a scanning electron microscope (SEM) image of the sludge solid sample in Example 3 of the present invention under anaerobic conditions; Figure 7 It is an X-ray diffraction (XRD) pattern of the sludge solid sample in Example 3 of the present invention under anaerobic conditions; Figure 8 It is the removal effect diagram of the tailings sample in Example 4 of the present invention for the wastewater containing butyl xanthate and arsenic with respect to butyl xanthate (BX) and arsenic under anaerobic and continuous flow conditions. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The technical solution of the present invention will be described below through specific specific examples. It should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combined steps or the insertion of other method steps between these clearly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. Moreover, unless otherwise specified, the numbers of each method step are only convenient tools for identifying each method step, rather than limiting the arrangement order of each method step or the scope in which the present invention can be implemented. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope in which the present invention can be implemented.

[0026] To better understand the above technical solution, the exemplary embodiments of the present invention will be described in more detail below. Although the exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention can be understood more thoroughly and the scope of the present invention can be completely conveyed to those skilled in the art.

[0027] The present invention will be further described below in conjunction with the following embodiments.

[0028] Example 1 A treatment process for activated sludge for treating wastewater contaminated with arsenic and butyl xanthate complex, including: Step 1, the process of collecting activated sludge: The original sample of the present invention was collected near the tail discharge port of the lead-zinc tailings in Renhua District, Shaoguan City, Guangdong Province, and then obtained through domestication and cultivation. The sample collection was carried out according to the "Mixed Sample Collection Method" in the "Technical Specification for Soil Environmental Monitoring" (HJ / T 166-2004). The plum blossom point sampling method was used to sample at fixed points, and surface, middle, and deep soil were collected from the soil near the tail discharge port into a sterile sampling bag, and stored for standby after refrigerated transportation at 4°C.

[0029] Step 2, the process of culturing and domesticating activated sludge: (1) Prepare the activated sludge culture solution: Calcium chloride 0.2460 g / L, magnesium chloride 1.0572 g / L, sodium chloride 0.4459 g / L, dipotassium hydrogen phosphate 0.0299 g / L, potassium chloride 0.0283 g / L, sodium bicarbonate 0.8082 g / L, ammonium chloride 0.1557 g / L.

[0030] (2) Mix the sludge: Add 150 mL of the culture medium prepared in (1) to the anaerobic bottle, and then add mine tailing sludge, sodium arsenate, and butyl xanthate to the bottle. After addition, the corresponding concentrations of activated sludge, sodium arsenate, and butyl xanthate in the anaerobic bottle are 3 g / L, 0.02 g / L, and 0.2 g / L.

[0031] (3) Sludge acclimation: After stirring evenly, introduce pure nitrogen into the anaerobic bottle for 20 min, and fix the acclimation conditions as: pH = 7.0, 25 °C, oscillating culture at 160 rpm / min for 10 - 14 d, then anaerobic activated sludge is obtained. Among them, the pH value is adjusted by 1 mol / L hydrochloric acid and sodium hydroxide solution. See the appendix for the results of 14 d of acclimation. Figure 2 After acclimation, the removal rates of butyl xanthate, corresponding TOC, and As 5+ are 95.45%, 82.71%, and 46.07% respectively, and the removal ability has been greatly improved compared with the original sample.

[0032] Step 3, 16S amplicon sequencing analysis: Perform 16S amplicon analysis on the original sludge sample and the acclimated sludge sample, and the sequencing is completed by Shanghai Bioengineering Co., Ltd. See the results in Figure 1 , and the microbial community composition and relative abundance can be known. The initial sample is activated sludge with Pseudomonadota (Pseudomonadota) 75.77% and Bacillota (Firmicutes) 9.41% as the dominant genera; the acclimated sample is anaerobic activated sludge with Pseudomonadota (Pseudomonadota) 90.80% and Bacteroidota (Bacteroidota) 6.14% as the dominant genera.

[0033] Example 2 This example is based on Example 1 to provide the application of activated sludge, and apply it to the biological treatment of wastewater contaminated with arsenic and butyl xanthate in combination. See the results in the attached drawings Figures 3 - 5 .

[0034] The specific process is as follows: Add 150 mL of the activated sludge culture medium prepared in Example 1 and the successfully acclimated anaerobic activated sludge to the anaerobic bottle, and then add sodium arsenate and butyl xanthate. After addition, the corresponding concentrations of activated sludge, sodium arsenate, and butyl xanthate in the anaerobic bottle are 3 g / L, 0.02 g / L, and 0.05 g / L. After stirring evenly, introduce pure nitrogen into the anaerobic bottle for 5 min, and fix the culture conditions as 25 °C, 160 rpm / min, pH = 7.0, and oscillate culture for 7 d.

[0035] The culture medium was taken at 0 h, 0.5 h, 1 h, 5 h, 10 h, 24 h, 36 h, 48 h, 72 h, 96 h, 120 h, and 144 h respectively, centrifuged at 5000 r / min at 4 °C for 5 - 10 min at low speed, and the supernatant was taken and passed through a 0.22 μm filter membrane, and then the TOC (total organic carbon) and A 301 (butyl xanthate), As 3+ , As 5+ and TAs (total arsenic) contents were measured respectively.

[0036] Three experimental groups with technical replicates and a blank control group were set up in the experiment. The control group was added with the same inoculum amount of normal saline.

[0037] Through this example and the Figures 3 - 5 in the accompanying drawings and Example 1 Figures 1 - 2 It can be seen that the activated sludge can utilize the organic carbon source in butyl xanthate to grow, reduce the content of xanthate, and achieve the reduction of As 5+ and the removal of TAs during the process. Under anaerobic conditions, the removal rate of butyl xanthate was 99.87%, the corresponding removal rate of TOC was 80.4%, the removal rate of As(V) was 72.93%, and the removal rate of TAs (total arsenic) was 65.26%.

[0038] Example 3 Based on Example 2, this example characterized the performance of the activated sludge after the treatment method. The specific items were SEM (scanning electron microscopy) and XRD (X-ray diffraction), which were completed by Hunan Navi New Materials Technology Co., Ltd. See the appendix Figure 6 and Figure 7 .

[0039] The activated sludge after treating the wastewater containing butyl xanthate and arsenic compound pollution in Example 2 was characterized. The SEM (scanning electron microscopy) results were as Figure 6 shown. The surface of the activated sludge presented an irregular blocky structure, which was relatively rough and had a large specific surface area, and might have a high reactivity for treating the wastewater with compound pollution. The XRD (X-ray diffraction) results were as Figure 7 shown. The peaks at 2θ = 29.42° and 33.02° (marked in the figure) belonged to As 4 S 4 and As 2 S 3 phase respectively. Under anaerobic conditions, there were many particles attached to the surface of the activated sludge, but the size was small. It was preliminarily judged that compounds containing sulfur and arsenic were formed on the activated sludge.

[0040] Example 4 This embodiment provides an application of the treatment method on the basis of Embodiment 1 and Embodiment 2, and applies it to the biological treatment of continuous-flow wastewater contaminated with arsenic and butyl xanthate. See Appendix Figure 8 .

[0041] The treatment process of the method for wastewater contaminated with arsenic and butyl xanthate is as follows: Add the successfully domesticated anaerobic activated sludge to the reactor, prepare 35 L of the culture solution according to the method in Embodiment 1, and add 2.915 g of disodium arsenate heptahydrate and 7 g of butyl xanthate, store them in the influent tank, and continuously pump the solution into the reactor at a flow rate of 0.8 mL / min through a peristaltic pump. The concentrations of the anaerobic activated sludge, sodium arsenate, and butyl xanthate after domestication in Embodiment 1 in the reactor are 3 g / L, 0.02 g / L, and 0.2 g / L respectively. The reaction conditions for continuous flow are: the hydraulic retention time (HRT) is set to 24 hours, and the dissolved oxygen (DO) is controlled between 0.5 - 1.0 mg / L through a nitrogen aeration device. The pH value is adjusted between 7.0 ± 1.0 by NaHCO 3 , the temperature is at room temperature, and continuous cultivation is carried out for 30 d. Take 1 sample every day (d), centrifuge the taken sample at a low speed in a refrigerated centrifuge at 5000 r / min and 4 °C for 5 - 10 min, and take the supernatant and pass it through a 0.22 μm filter membrane and then measure A 301 (butyl xanthate), As 3+ , As 5+ and TAs contents.

[0042] Through this embodiment and Appendix Figure 8 It can be seen that under the conditions of continuous-flow cultivation, the activated sludge can remove high-concentration xanthate and reduce and remove arsenate more efficiently than the activated sludge cultivated within 7 d (Embodiment 2). Under anaerobic conditions, 200 mg / L of butyl xanthate can be basically completely removed before 14 d, and the final removal rate is 99.64%; the arsenate drops rapidly in the first 3 d and is continuously and stably reduced and removed in the subsequent process. The reduction rate of As(V) is 96.13%, and the removal rate of TAs is 94.70%.

[0043] Based on the above embodiments, the treatment method provided by the present invention can be widely applied to the field of treatment of mine composite polluted wastewater containing arsenic and butyl xanthate. The activated sludge in the method of the present invention is Pseudomonadota (Pseudomonadota) 90.80% and BacteroidotaThe activated sludge with Bacteroidetes as the dominant genus (6.14%) has a strong adaptability to arsenic-polluted environments. It can reduce arsenic without additional addition of organic carbon sources and can also effectively oxidize and remove xanthate, meeting the requirements of low-cost and high-efficiency removal of arsenic and xanthate in oligotrophic mining areas and other places. Under anaerobic conditions, the microorganisms in the activated sludge can oxidize butyl xanthate and use its carbon source to reduce and immobilize arsenate. The removal rate of 50 mg / L butyl xanthate within 7 days is 99.96%, the corresponding TOC (total organic carbon) utilization rate is 80.4%, the As(V) reduction rate is 72.93%, and the TAs (total arsenic) removal rate is 65.26%. Under continuous flow conditions, the removal rate of 200 mg / L butyl xanthate within 30 days is 99.64%, the As(V) reduction rate is 96.13%, and the TAs (total arsenic) removal rate is 94.70%.

[0044] Applying this method to the treatment of wastewater containing xanthate and arsenic in mining areas is conducive to simplifying the wastewater treatment process, improving the treatment efficiency, meeting the requirements of environmental friendliness, having good economic and environmental benefits, overcoming the problem of difficult growth of organisms caused by insufficient carbon sources, making it possible to synchronously remove xanthate and other beneficiation reagents and arsenic, and having broad application prospects.

[0045] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0046] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing activated sludge for treating wastewater contaminated with arsenic and butyl xanthate, characterized in that: The following steps are involved: Step 1, taking soil near the lead-zinc tailings as an original sample to obtain initial sludge; Step 2, preparing a culture solution for culturing the sludge; Step 3, adding culture solution to the anaerobic bottle, and then placing the initial sludge into the bottle; Step 4, adding sodium arsenate and butyl xanthate into the bottle, stirring evenly to discharge oxygen, and oscillating and culturing to obtain anaerobic activated sludge that has been domesticated and cultured.

2. The method for preparing activated sludge for treating wastewater contaminated with arsenic and butyl xanthate according to claim 1, characterized in that: In step 1, the samples are collected by using the plum blossom point sampling method to collect surface, middle and deep soil from the soil near the tailings outlet of the mine in sterile sampling bags, which are then refrigerated for transportation and storage.

3. The method for preparing activated sludge for treating wastewater contaminated with arsenic and butyl xanthate according to claim 1, characterized in that: The initial microbial community in the soil near the lead-zinc tailings includes: Pseudomonadota (Pseudomonas) 75.77%, Bacillota (Firmicutes) 9.41%, Nitrospirota (Nitrospira) 3.54%, Deinococcota (Deinococcus) 2.84%, Actinomycetota (Actinobacteria) 1.22%, Dependentiae (Dependent bacteria) 1.01% and other microorganisms 6.21%.

4. The method for preparing activated sludge for treating wastewater contaminated with arsenic and butyl xanthate according to claim 1, characterized in that: In step 2, the components in the culture solution are calculated by concentration, including: calcium chloride of 0.2460 g / L, magnesium chloride of 1.0572 g / L, sodium chloride of 0.4459 g / L, dipotassium hydrogen phosphate of 0.0299 g / L, potassium chloride of 0.0283 g / L, sodium bicarbonate of 0.8082 g / L, and ammonium chloride of 0.1557 g / L.

5. The method for preparing activated sludge for treating wastewater contaminated with arsenic and butyl xanthate according to claim 1, characterized in that: In step 3, the pH is adjusted to 7.0±0.1 and the initial sludge concentration is 3.0 g / L.

6. The method for preparing activated sludge for treating wastewater contaminated with arsenic and butyl xanthate according to claim 1, characterized in that: In step 4, the concentration of sodium arsenate after addition is 0.01-0.03 g / L, and the concentration of butyl xanthate after addition is 0.1-0.3 g / L.

7. The method for preparing activated sludge for treating wastewater contaminated with arsenic and butyl xanthate according to claim 1, characterized in that: In step 4, the oxygen is discharged by passing pure nitrogen into the anaerobic bottle for at least 20 minutes; the shaking culture temperature is 25°C, the speed is 150-180 r / min, and the culture time is 10-14 days.

8. The method for preparing activated sludge for treating wastewater contaminated with arsenic and butyl xanthate according to claim 1, characterized in that: In step 4, the microbial community of the anaerobic activated sludge includes: Pseudomonadota (Pseudomonas) 90.80%, Bacteroidota (Bacteroidetes) 6.14%, Dependentiae (Dependent bacteria) 2.41% and other microorganisms 0.65%.

9. An activated sludge for treating wastewater contaminated with arsenic and butyl xanthate, characterized in that: The preparation method according to claim 1 is used for preparation.

10. Use of the activated sludge according to claim 9 in treating wastewater contaminated with arsenic and butyl xanthate.

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