Surface mine low-pollution drainage water treatment method

Abstract

The invention relates to a surface mine low-pollution drainage water treatment method, and belongs to the technical field of drainage water treatment. Comprising the following steps: (1) standing and settling to-be-treated drainage water for a period of time; (2) sequentially adding sodium hypochlorite, PAC and PAM into the drained water after standing and settling, and stirring to purify the drained water; (3) carrying out oxygen aeration treatment on the drained water subjected to purification treatment in the step (2); and (4) standing and settling the aerated drained water for a period of time to obtain the upgraded drained water. According to the treatment method, on-site treatment is conducted on the basis of an existing site, only an aeration device and an agent adding device need to be additionally arranged, the equipment investment is small, the treatment process is simple, and efficient treatment on the low-pollution drainage water of the surface mine can be achieved through sodium hypochlorite, PAC and PAM.

Description

Technical Field

[0001] The present application relates to the technical field of drainage water treatment, and in particular to a low-pollution drainage water treatment method for open-pit mines. Background Art

[0002] Drainage water refers to wastewater containing various pollutants that emerges from the coal seam during coal mining. The composition of drainage water is affected by the regional hydrology, geological characteristics and mining technology. It is generally complex and contains a large amount of suspended matter such as sand, coal, grease, and some dissolved salts, acids and alkalis.

[0003] Drainage water often contains a large amount of ammonia nitrogen, and its sources are mainly the following: first, the organic nitrogen and inorganic nitrogen in the mineral layer can be dissolved in the groundwater and discharged subsequently; second, during the mining process, chemical agents such as fire prevention and extinguishing, grouting, and gel materials used in the mining area may be mixed into the drainage water; third, the replenishment of surface ammonia nitrogen-contaminated water, such as agricultural drainage, domestic sewage, etc.; fourth, the decomposition of microorganisms converts organic nitrogen into ammonia nitrogen.

[0004] At the same time, in addition to the high content of ammonia nitrogen in the drainage water, there are also COD, Fe 2+ Although some existing drainage water treatment methods can effectively treat drainage water, most of them need to rely on specific treatment devices or adsorption materials, which leads to high investment and treatment costs.

[0005] How to achieve efficient treatment of low-pollution drainage water from open-pit mines while reducing investment in equipment and even site construction and lowering treatment costs, so that the treated water quality meets the Class III standard limit requirements in the "Surface Water Environmental Quality Standard" (GB3838-2002) has always been a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0006] In order to solve or partially solve the problems existing in the related art, the present application provides a method for treating low-pollution drainage water from an open-pit mine. The method relies on the existing site for on-site treatment. It only needs to add an aeration device and a reagent dosing device. The equipment investment is small and the treatment process is simple. Sodium hypochlorite, PAC and PAM can be used to achieve efficient treatment of low-pollution drainage water from open-pit mines, so that the treated water quality meets the Class III standard in the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0007] The present application discloses a method for treating low-pollution drainage water in an open-pit mine, comprising the following steps:

[0008] (1) allowing the drained water to be treated to settle for a period of time;

[0009] (2) adding sodium hypochlorite, PAC and PAM to the drained water after static sedimentation in sequence and stirring to purify the drained water;

[0010] (3) subjecting the drained water after the purification treatment in step (2) to oxygen exposure treatment;

[0011] (4) The aerated drainage water is allowed to settle for a period of time to obtain the improved drainage water.

[0012] Furthermore, the drained water to be treated has a COD of less than 50 mg / L, a SS of less than 10 mg / L, a turbidity of less than 140 NTU, ammonia nitrogen of less than 2 mg / L, a total phosphorus of less than 1 mg / L, and a total iron of less than 10 mg / L.

[0013] Furthermore, the static sedimentation time in step (1) and step (4) is 10-30 minutes.

[0014] Furthermore, the specific operation of oxygen aeration treatment in step (3) is: continuously aerating oxygen through an aeration device, and the aeration rate is ≥1.95 kg / h.

[0015] Furthermore, the addition amount of the sodium hypochlorite is 80-200 mg / L; the addition amount of the PAC is 250-710 mg / L, and the addition amount of the PAM is 25-70 mg / L.

[0016] Mechanism of action of this application:

[0017] 1. The purpose of the first static sedimentation of low-pollution drainage water from open-pit mines is to reduce the total phosphorus factor in the water by static sedimentation;

[0018] 2. The purpose of adding sodium hypochlorite, PAC and PAM is to remove nitrogen ions and settle suspended matter in turn.

[0019] 3. The purpose of aeration treatment of drainage water is: the iron and manganese ions in drainage water exceed the standard seriously. Aeration can oxidize divalent iron ions into trivalent iron ions. Trivalent iron ions are insoluble in water and can settle with suspended matter.

[0020] 4. The purpose of the second static sedimentation of low-pollution drainage water from open-pit mines is to stabilize the water quality and eventually reuse or discharge it.

[0021] Beneficial effects of this application:

[0022] The treatment method in this application relies on the existing site for on-site treatment. It only requires the addition of an aeration device and a reagent dosing device. The equipment investment is small and the treatment process is simple. Sodium hypochlorite, PAC and PAM can be used to achieve efficient treatment of low-pollution drainage water from open-pit mines. DETAILED DESCRIPTION

[0023] The embodiments of the present application will be described in more detail below with reference to examples. Although the embodiments of the present application are shown in the examples, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and the scope of the present application can be fully communicated to those skilled in the art.

[0024] Example 1

[0025] A method for treating low-pollution drainage water in an open-pit mine in this embodiment includes the following steps:

[0026] (1) The drained water to be treated is allowed to settle for a period of time; the settling time is 10 minutes;

[0027] The chemical composition of the drainage water to be treated is as follows:

[0028] Drainage water COD≤150mg / L, SS≤50mg / L, turbidity 190NTU, ammonia nitrogen 1.8mg / L, total phosphorus 0.3mg / L, total iron 9.5mg / L;

[0029] (2) Sodium hypochlorite, PAC and PAM are added to the drained water after static sedimentation in sequence, and stirred to purify the drained water; the amount of sodium hypochlorite added is 150 mg / L; the amount of PAC added is 250 mg / L, and the amount of PAM added is 70 mg / L.

[0030] (3) aerating the drained water after the purification treatment in step (2); the specific operation of aeration is as follows:

[0031] The aeration pump continuously pumps oxygen into the water (4). The aerated drained water is allowed to settle for a period of time. The settling time is 30 minutes, and the improved drained water is obtained.

[0032] Among them, after testing, the drainage water after quality improvement fully meets the Class III standard in the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0033] Example 2

[0034] (1) The drained water to be treated is allowed to settle for a period of time; the settling time is 25 minutes;

[0035] The chemical composition of the drainage water to be treated is as follows:

[0036] Drainage water COD≤150mg / L, SS≤50mg / L, turbidity 190NTU, ammonia nitrogen 1.8mg / L, total phosphorus 0.3mg / L, total iron 8.5mg / L;

[0037] (2) Sodium hypochlorite, PAC and PAM are sequentially added to the drained water after static sedimentation, and stirred to purify the drained water; the amount of sodium hypochlorite added is 80 mg / L; the amount of PAC added is 550 mg / L, and the amount of PAM added is 50 mg / L.

[0038] (3) aerating the drained water after the purification treatment in step (2); the specific operation of aeration is as follows:

[0039] The aeration pump continuously pumps oxygen into the water (4). The aerated drainage water is allowed to settle for 30 minutes to obtain the improved drainage water.

[0040] Among them, after testing, the drainage water after quality improvement fully meets the Class III standard in the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0041] Example 3

[0042] (1) The drained water to be treated is allowed to settle for a period of time; the settling time is 30 minutes;

[0043] The chemical composition of the drainage water to be treated is as follows:

[0044] Drainage water COD≤150mg / L, SS≤50mg / L, turbidity 190NTU, ammonia nitrogen 1.8mg / L, total phosphorus 0.3mg / L, total iron 9mg / L;

[0045] (2) Sodium hypochlorite, PAC and PAM are added to the drained water after static sedimentation in sequence, and stirred to purify the drained water; the amount of sodium hypochlorite added is 200 mg / L; the amount of PAC added is 250 mg / L, and the amount of PAM added is 25 mg / L.

[0046] (3) aerating the drained water after the purification treatment in step (2); the specific operation of aeration is as follows:

[0047] The aeration pump continuously pumps oxygen into the water (4). The aerated drained water is allowed to settle for a period of time, the settling time being 20 minutes, and the improved drained water is obtained.

[0048] Among them, after testing, the drainage water after quality improvement fully meets the Class III standard in the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0049] Comparative Example 1

[0050] The drainage water treatment method in this comparative example is the same as that in Example 1 except that the static sedimentation in step (1) in Example 1 is not performed.

[0051] Testing of the treated drained water showed that it did not meet Class III standards in the Surface Water Environmental Quality Standards (GB3838-2002).

[0052] Comparative Example 2

[0053] The drainage water treatment method in this comparative example is the same as that in Example 1 except that the further static sedimentation in step (4) in Example 1 is not performed.

[0054] Testing of the treated drained water showed that it did not meet Class III standards in the Surface Water Environmental Quality Standards (GB3838-2002).

[0055] Comparative Example 3

[0056] The drainage water treatment method in this comparative example is the same as that in Example 1, except that the static sedimentation in step (1) of Example 1 and the static sedimentation again in step (4) of Example 1 are not performed.

[0057] Testing of the treated drained water showed that it did not meet Class III standards in the Surface Water Environmental Quality Standards (GB3838-2002).

[0058] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for treating low-pollution drainage water in an open-pit mine, characterized in that: The steps include: (1) allowing the drained water to be treated to settle for a period of time; (2) adding sodium hypochlorite, PAC and PAM to the drained water after static sedimentation in sequence and stirring to purify the drained water; (3) subjecting the drained water after the purification treatment in step (2) to oxygen exposure treatment; (4) The aerated drainage water is allowed to settle for a period of time to obtain the improved drainage water.

2. The open-pit mine low-pollution drainage water treatment method according to claim 1, characterized in that: The drained water to be treated has a COD of less than 50 mg / L, a SS of less than 10 mg / L, a turbidity of less than 140 NTU, ammonia nitrogen of less than 2 mg / L, a total phosphorus of less than 1 mg / L, and a total iron of less than 10 mg / L.

3. The open-pit mine low-pollution drainage water treatment method according to claim 2, characterized in that: The static sedimentation time in step (1) and step (4) is 10-30 minutes.

4. The open-pit mine low-pollution drainage water treatment method according to claim 2, characterized in that: The specific operation of oxygen aeration treatment in step (3) is: continuously aerating oxygen through an aeration device, and the aeration rate is ≥1.95 kg / h.

5. The open-pit mine low-pollution drainage water treatment method according to claim 2, characterized in that: According to the water inlet conditions, the amount of reagent added is 80-200 mg / L for sodium hypochlorite, 250-710 mg / L for PAC, and 25-70 mg / L for PAM.