Combined application method for sewage treatment

Abstract

The invention relates to the technical field of environmental protection, and discloses a sewage treatment combined application method, which comprises the following steps: adding bentonite, zeolite, silica and red mud into a physical adsorption sedimentation tank to primarily adsorb sewage wastewater; sewage subjected to primary treatment is discharged to a primary water storage tank by the physical adsorption sedimentation tank, and water discharged from the primary water storage tank to the chemical sedimentation tank is controlled by a water storage tank water level regulation and control end; a sodium hydroxide solution and a precipitant are respectively added into different chemical precipitation tanks to remove copper ions, magnesium ions and phosphate. According to whether the pollution degree of discharged water exceeds the degradation capacity range of river water in a discharge area or not, the water level regulation and control end of the reservoir regulates and controls the flow rate of water discharged from the sedimentation tank to the reservoir, and then the purification time of sewage in the sedimentation tank is controlled, and by means of the regulation and control method, the ecological environment of the river water can be really not changed; and the sewage treatment efficiency is not reduced.

Description

Technical Field

[0001] The invention relates to the technical field of environmental protection, and in particular to a combined application method for sewage treatment. Background Art

[0002] The existing patent (publication number CN101659498A) discloses a composite artificial wetland treatment process for domestic sewage in rural towns. In the technology disclosed in the patent, the discharged water is only tested according to the test indicators and test standards in the factory, but the actual impact of the discharged water on the biological population in the ecological environment after discharge is not considered. After years of accumulation, this discharge method will eventually cause serious eutrophication in the ecological environment, affect the ecological environment of the river water, and reduce the efficiency of sewage treatment. Summary of the invention

[0003] The main technical problem solved by the present invention is that the existing technology affects the ecological environment of river water and the sewage treatment efficiency is low. In order to solve the above technical problems, the present invention provides a sewage treatment combined application method, comprising the following steps:

[0004] S1. Adding bentonite, zeolite, silica and red mud into a physical adsorption sedimentation tank;

[0005] S2. The initially treated sewage is discharged into the primary water reservoir in the physical adsorption sedimentation tank, and the primary water reservoir then discharges water into the chemical sedimentation tank, and the discharge of water from the primary water reservoir to the chemical sedimentation tank is controlled by the water level control end of the water reservoir;

[0006] S3, adding sodium hydroxide solution and precipitant to the chemical precipitation tank respectively;

[0007] S4, discharging the treated sewage from the chemical sedimentation tank to the secondary water reservoir, which then discharges the sewage to the electrochemical sedimentation tank, and the discharge of the sewage from the secondary water reservoir to the electrochemical sedimentation tank is controlled by the water level control end of the water reservoir;

[0008] S5. The wastewater treated in the electrochemical sedimentation tank is then discharged to the tertiary water reservoir, and the tertiary water reservoir then discharges water to the photocatalytic sedimentation tank, and the drainage from the tertiary water reservoir to the photocatalytic sedimentation tank is controlled by the water level control end of the water reservoir;

[0009] S6. Adding a photocatalyst into the photocatalytic precipitation tank;

[0010] S7, detect whether the sewage in the photocatalytic sedimentation tank meets the standards, and discharge it to the fourth-level water storage tank when the sewage monitoring meets the standards;

[0011] S8. The discharge of water from the fourth-level reservoir to the river is controlled by the water level control end of the reservoir.

[0012] Furthermore, the water level control end of the reservoir determines the river pollution index of the discharge area according to the difference in the amount of plankton in the sampled river water collected between the upstream sampling point and the downstream sampling point, the difference in the total amount of aquatic organisms covered on the riverbed per unit area, and the heavy metal content index of the river water, which are:

[0013] ;

[0014] In the formula, Indicates the river water pollution index coefficient of the discharge area, It represents the difference in the total amount of plankton in the sampled river water between the upstream sampling point and the downstream sampling point. It represents the difference in the total amount of aquatic organisms covered per unit area of ​​the riverbed between the upstream sampling point and the downstream sampling point. It indicates the index coefficient of heavy metal content in river water in the discharge area.

[0015] Furthermore, the water level control end of the reservoir determines the heavy metal content index coefficient of the river water in the discharge area according to the heavy metal content index of the area between the upstream sampling point and the downstream sampling point of the river, that is, the size of calcium hardness, the size of magnesium hardness and the chemical oxygen demand per unit volume of river water, which is:

[0016] ;

[0017] In the formula, Indicates the index coefficient of heavy metal content in river water in the discharge area, The larger the value, the higher the heavy metal content in the river water; Indicates the degree of calcium hardness in the river water of the discharge area; Indicates the degree of magnesium hardness in the river water of the discharge area; Indicates the chemical oxygen demand in the river water of the discharge area.

[0018] Furthermore, when When the treated water discharge area obviously exceeds the natural degradation capacity of the river, it is necessary for the water storage tanks at all levels to reduce the discharge flow to the sedimentation tank by no less than 20%;

[0019] when When the treated water discharge area exceeds the natural degradation capacity of the river, it is necessary for the water storage tanks at all levels to reduce the discharge flow to the sedimentation tank by no less than 10%;

[0020] when When , it means that the discharge area of ​​treated water has not exceeded the natural degradation capacity of the river, and there is no need to reduce the discharge flow.

[0021] Furthermore, in step S1, the mass ratio of bentonite, zeolite, silica and red mud in each physical adsorption sedimentation tank is .

[0022] Furthermore, in step S3, the mass ratio of the amount of sodium hydroxide solution added to the injected water is The mass ratio of the amount of precipitant added to the injected water is .

[0023] Furthermore, in step S5, the electrochemical sedimentation tank first removes cyanide and sulfide in the sewage by electrolysis, and then precipitates the pollutants in the sewage by the action of the electric field.

[0024] Furthermore, in step S6, the mass ratio of the catalyst in the photocatalytic precipitation tank to the injected water is .

[0025] Furthermore, in step S7, the photocatalytic sedimentation tank needs to undergo water quality testing before drainage. The water quality test determines whether the discharged water of the photocatalytic sedimentation tank meets the standards based on the concentration of ammonia in the discharged water, the concentration of the sum of all forms of phosphorus in the discharged water, and the concentration of the sum of all forms of nitrogen in the discharged water. Then:

[0026] ;

[0027] In the formula, Indicates the compliance coefficient of discharged water, Indicates the concentration of ammonia in the discharged water. It represents the total concentration of all forms of phosphorus in the discharged water. Represents the total concentration of all forms of nitrogen in the discharged water.

[0028] Furthermore, when When , it means that the water finally discharged from the photocatalytic sedimentation tank meets the discharge standards of the wastewater treatment plant;

[0029] when When , it means that the water finally discharged from the photocatalytic sedimentation tank does not meet the discharge standards of the wastewater treatment plant.

[0030] Beneficial effects:

[0031] 1. The present invention allows the water level control end of the reservoir to regulate the flow of water from the sedimentation tank to the reservoir according to whether the pollution degree of the discharged water exceeds the degradation capacity of the river water in the discharge area, thereby controlling the purification time of the sewage in the sedimentation tank. This control method can not only truly not change the ecological environment of the river water, but also will not reduce the sewage treatment efficiency.

[0032] 2. The present invention controls the retention time of sewage in the sedimentation tank in disguised form by controlling the discharge flow rate from the sedimentation tank to the water reservoir, that is, by reducing the pumping flow rate from the sedimentation tank to the water reservoir, the retention time of sewage in the sedimentation tank can be increased to increase the purification time, and by increasing the pumping flow rate from the sedimentation tank to the water reservoir, the retention time of sewage in the sedimentation tank can be reduced to reduce the purification time.

[0033] 3. The present invention determines the purification time of the sedimentation tank in the sewage treatment plant through the water level control end of the reservoir according to the difference in plankton mass in the sampled river water collected between the upstream sampling point and the downstream sampling point of the river, the difference in the total amount of aquatic organisms covered on the riverbed per unit area, and the heavy metal content index of the river water. This judgment index can not only accurately summarize the river water conditions, but also reduce the sample sampling amount and calculation amount.

[0034] 4. The present invention can simply and clearly determine whether the discharge water treated by the physical adsorption sedimentation tank, chemical sedimentation tank, electrochemical and photocatalytic sedimentation tank meets the pollution discharge standards based on the concentration of ammonia in the discharge water, the concentration of the sum of all forms of phosphorus in the discharge water and the concentration of the sum of all forms of nitrogen in the discharge water. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of sampling points in the present invention;

[0036] Figure 2 is a flow chart of the present invention;

[0037] Figure 3 It is a schematic diagram of a sedimentation tank in the present invention;

[0038] Figure 4 For the control of the present invention The model graph of G constructed by the variables. DETAILED DESCRIPTION

[0039] In order to make the technical solution of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] like Figures 1 to 4 As shown, the present invention provides a combined application method for sewage treatment, comprising the following steps:

[0041] Step 1: Preliminary adsorption of the discharged wastewater by adding bentonite, zeolite, silica and red mud in the physical adsorption sedimentation tank. The mass ratio of bentonite, zeolite, silica and red mud in each physical adsorption sedimentation tank is The physical adsorption sedimentation tank adsorbs impurities into bentonite, zeolite, silica, and red mud, which can be removed by regularly replacing the bentonite, zeolite, silica, and red mud.

[0042] Step 2: The physical adsorption sedimentation tank discharges the preliminarily treated sewage into the primary water reservoir. The drainage from the primary water reservoir to the chemical sedimentation tank is controlled by the water level control end of the water reservoir. In this way, the retention time of sewage in the sedimentation tank is controlled in disguise by controlling the discharge flow from the sedimentation tank to the water reservoir.

[0043] Step 3: Remove copper ions, magnesium ions and phosphates by adding sodium hydroxide solution and precipitant to different chemical precipitation tanks; the mass ratio of the amount of sodium hydroxide solution added to the injected water is The mass ratio of the amount of precipitant added to the injected water is In the chemical sedimentation tank, sodium hydroxide solution is added to form salt precipitation with copper ions and magnesium ions in the sewage, and precipitants are added to form calcium salt precipitation with phosphates in the sewage.

[0044] Step 4: Discharge the treated sewage from the chemical sedimentation tank into the secondary water reservoir. The drainage from the secondary water reservoir to the electrochemical sedimentation tank is controlled by the water level control end of the water reservoir. In this way, the retention time of sewage in the sedimentation tank can be controlled in disguise by controlling the discharge flow from the sedimentation tank to the water reservoir.

[0045] Step 5: The electrochemical sedimentation tank first removes cyanide and sulfide from the sewage through electrolysis, and then precipitates the pollutants in the sewage through the action of the electric field. The electrochemical sedimentation tank uses the action of the electric field to make the cyanide and sulfide in the sewage adsorb and aggregate and settle, thereby filtering the free cyanide and sulfide in the sewage.

[0046] Step 6. The sewage treated by the electrochemical sedimentation tank is then discharged into the tertiary water reservoir. The drainage from the tertiary water reservoir to the photocatalytic sedimentation tank is controlled by the water level regulating end of the water reservoir. In this way, the retention time of sewage in the sedimentation tank can be controlled in disguise by controlling the discharge flow from the sedimentation tank to the water reservoir.

[0047] Step 7: Add photocatalyst to the photocatalytic sedimentation tank and degrade organic matter and bacteria in the sewage through long-term illumination; the mass ratio of the catalyst in the photocatalytic sedimentation tank to the injected water is Photocatalysis decomposes organic matter and bacteria into water and carbon dioxide.

[0048] Step 8: Check whether the sewage in the photocatalytic sedimentation tank meets the standards. When the sewage meets the standards, it will be discharged into the fourth-level water storage tank.

[0049] Step 9. The drainage of the four-stage reservoir to the river is controlled by the water level regulating end of the reservoir. In this way, the retention time of sewage in the sedimentation tank is controlled in disguise by controlling the discharge flow from the sedimentation tank to the reservoir.

[0050] Example 1

[0051] The water level control end of the reservoir determines the heavy metal content index coefficient of the river water in the discharge area based on the heavy metal content index of the area between the upstream sampling point and the downstream sampling point of the river, that is, the size of calcium hardness, the size of magnesium hardness and the chemical oxygen demand per unit volume of river water, which are:

[0052] ;

[0053] In the formula, Indicates the index coefficient of heavy metal content in river water in the discharge area, The larger the value, the higher the heavy metal content in the river water; Indicates the degree of calcium hardness in the river water of the discharge area; Indicates the degree of magnesium hardness in the river water of the discharge area; Indicates the chemical oxygen demand in the river water of the discharge area.

[0054] Among them, data collection is carried out on river water sampling sample X. The magnitude of calcium hardness in the river water in the discharge area is taken (mg / L), the magnesium hardness in the river water of the discharge area is (mg / L), the chemical oxygen demand in the river water of the discharge area is (Unit: mg / L, chemical oxygen demand refers to the amount of oxygen required to be consumed by all oxidizable substances in a water sample under the action of a strong oxidant). Then we have:

[0055] ;

[0056] From the above calculation, we can know that the index coefficient of heavy metal content in river water sample X is . And, if multiple groups of sample data are collected and compared, then:

[0057] Table 1: Sample data of river water sampling sample X

[0058]

[0059] From the data in Table 1, we can see that The larger the value, the higher the heavy metal content in the river water.

[0060] The water level control end of the reservoir determines the river pollution index of the discharge area based on the difference in the amount of plankton in the sampled river water between the upstream sampling point and the downstream sampling point, the difference in the total amount of aquatic organisms covered on the riverbed per unit area, and the heavy metal content index of the river water, which are:

[0061] ;

[0062] In the formula, Indicates the river water pollution index coefficient of the discharge area, It represents the difference in the total amount of plankton in the sampled river water between the upstream sampling point and the downstream sampling point. It represents the difference in the total amount of aquatic organisms covered per unit area of ​​the riverbed between the upstream sampling point and the downstream sampling point. Indicates the index coefficient of heavy metal content in river water in the discharge area;

[0063] when When the treated water discharge area obviously exceeds the natural degradation capacity of the river, it is necessary for the water storage tanks at all levels to reduce the discharge flow to the sedimentation tank by no less than 20%;

[0064] when When the treated water discharge area exceeds the natural degradation capacity of the river, it is necessary for the water storage tanks at all levels to reduce the discharge flow to the sedimentation tank by no less than 10%;

[0065] when When , it means that the discharge area of ​​treated water has not exceeded the natural degradation capacity of the river, and there is no need to reduce the discharge flow.

[0066] Among them, samples were collected and tested at two sampling points of river water. The difference in the total amount of plankton in the sampled river water between the upstream sampling point and the downstream sampling point was taken. (Unit: algae cells / cubic millimeter, the difference in total amount = the number of algae cells in one cubic millimeter of river water at the downstream sampling point - the number of algae cells in one cubic millimeter of river water at the upstream sampling point. If the difference in total amount is a negative number, take ).

[0067] The difference in the total amount of aquatic organisms per unit area of ​​the riverbed between the upstream sampling point and the downstream sampling point is taken as (Unit: g / m², total amount difference = total mass of benthic animals active on one square meter of riverbed at the downstream sampling point - total mass of benthic animals active on one square meter of riverbed at the upstream sampling point. If the total amount difference is negative, take ), then we have:

[0068] ;

[0069] From the above calculation, we can know that the river water pollution index coefficient in the discharge area is The discharge area obviously exceeds the natural degradation capacity of the river. At this time, it is necessary for each level of reservoir to reduce the discharge flow to the sedimentation tank by no less than 20%. And compare multiple sets of data:

[0070] Table 2: River water pollution data in the discharge area

[0071]

[0072] From the data in Table 2, we can see that when the sample data tends to infinity, the pollution index coefficient will have an obvious critical value for whether the river water is eutrophic, which is 73% and 41%. When , it means that the discharge area of ​​treated water obviously exceeds the natural degradation capacity of the river. When , it means that the discharge area of ​​treated water exceeds the natural degradation capacity of the river; when When , it means that the discharge area of ​​treated water has not exceeded the natural degradation capacity of the river.

[0073] Example 2

[0074] Before the photocatalytic sedimentation tank is discharged, it needs to undergo water quality testing to determine whether it is qualified. The water quality test is based on the concentration of ammonia in the discharged water, the concentration of the sum of all forms of phosphorus in the discharged water, and the concentration of the sum of all forms of nitrogen in the discharged water to determine whether the discharged water of the photocatalytic sedimentation tank meets the standards. Then there are:

[0075] ;

[0076] In the formula, Indicates the compliance coefficient of discharged water, Indicates the concentration of ammonia in the discharged water. It represents the total concentration of all forms of phosphorus in the discharged water. Represents the total concentration of all forms of nitrogen in the discharged water.

[0077] when When , it means that the water finally discharged from the photocatalytic sedimentation tank meets the discharge standards of the wastewater treatment plant;

[0078] when When , it means that the water finally discharged from the photocatalytic sedimentation tank does not meet the discharge standards of the wastewater treatment plant.

[0079] Among them, the sample of the discharged water sample Y is tested. The concentration of ammonia in the discharged water is taken (mg / L). The total concentration of all forms of phosphorus in the discharged water is (mg / L). The total concentration of all forms of nitrogen in the discharged water is (mg / L), then:

[0080] ;

[0081] From the above calculation, we can know that the compliance coefficient of the discharged water sample Y after testing is The water discharged from the photocatalytic sedimentation tank meets the discharge standards of the wastewater treatment plant. And by comparing multiple groups of implementation data, there are:

[0082] Table 3: Sample data of discharge water sample Y

[0083]

[0084] From the sample data in Table 3, we can see that When , it means that the water finally discharged from the photocatalytic sedimentation tank meets the discharge standard of the wastewater treatment plant; when When , it means that the water finally discharged from the photocatalytic sedimentation tank does not meet the discharge standards of the wastewater treatment plant.

[0085] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A combined application method for sewage treatment, characterized in that: The following steps are involved: S1. Adding bentonite, zeolite, silica and red mud into a physical adsorption sedimentation tank; S2. The initially treated sewage is discharged into the primary water reservoir in the physical adsorption sedimentation tank, and the primary water reservoir then discharges water into the chemical sedimentation tank, and the discharge of water from the primary water reservoir to the chemical sedimentation tank is controlled by the water level control end of the water reservoir; S3, adding sodium hydroxide solution and precipitant to the chemical precipitation tank respectively; S4, discharging the treated sewage from the chemical sedimentation tank to the secondary water reservoir, which then discharges the sewage to the electrochemical sedimentation tank, and the discharge of the sewage from the secondary water reservoir to the electrochemical sedimentation tank is controlled by the water level control end of the water reservoir; S5. The wastewater treated in the electrochemical sedimentation tank is then discharged to the tertiary water reservoir, and the tertiary water reservoir then discharges water to the photocatalytic sedimentation tank, and the drainage from the tertiary water reservoir to the photocatalytic sedimentation tank is controlled by the water level control end of the water reservoir; S6. Adding a photocatalyst into the photocatalytic precipitation tank; S7, detect whether the sewage in the photocatalytic sedimentation tank meets the standards, and discharge it to the fourth-level water storage tank when the sewage monitoring meets the standards; S8, the discharge of water from the fourth-level reservoir to the river is controlled by the reservoir water level control end; The water level control end of the reservoir determines the river pollution index of the discharge area according to the difference in the amount of plankton in the sampled river water collected between the upstream sampling point and the downstream sampling point, the difference in the total amount of aquatic organisms covered on the riverbed per unit area, and the heavy metal content index of the river water, which are: ； In the formula, Indicates the river water pollution index coefficient of the discharge area, It represents the difference in the total amount of plankton in the sampled river water between the upstream sampling point and the downstream sampling point. It represents the difference in the total amount of aquatic organisms covered per unit area of ​​the riverbed between the upstream sampling point and the downstream sampling point. It indicates the index coefficient of heavy metal content in river water in the discharge area.

2. The combined application method for sewage treatment according to claim 1, characterized in that: when When the treated water discharge area obviously exceeds the natural degradation capacity of the river, it is necessary for the water storage tanks at all levels to reduce the discharge flow to the sedimentation tank by no less than 20%; when When the treated water discharge area exceeds the natural degradation capacity of the river, it is necessary for the water storage tanks at all levels to reduce the discharge flow to the sedimentation tank by no less than 10%; when When , it means that the discharge area of ​​treated water has not exceeded the natural degradation capacity of the river, and there is no need to reduce the discharge flow.

3. The combined application method for sewage treatment according to claim 2, characterized in that: The water level control end of the reservoir determines the heavy metal content index coefficient of the river water in the discharge area according to the heavy metal content index of the area between the upstream sampling point and the downstream sampling point of the river, that is, the size of calcium hardness, the size of magnesium hardness and the chemical oxygen demand per unit volume of river water, which is: ； In the formula, Indicates the index coefficient of heavy metal content in river water in the discharge area, The larger the value, the higher the heavy metal content in the river water; Indicates the degree of calcium hardness in the river water of the discharge area; Indicates the degree of magnesium hardness in the river water of the discharge area; Indicates the chemical oxygen demand in the river water of the discharge area.

4. The combined application method for sewage treatment according to claim 1, characterized in that: In step S1, the mass ratio of bentonite, zeolite, silica and red mud in each physical adsorption sedimentation tank is .

5. The combined application method for sewage treatment according to claim 1, characterized in that: In step S3, the mass ratio of the amount of sodium hydroxide solution added to the injected water is .

6. The combined application method for sewage treatment according to claim 1, characterized in that: In step S3, the mass ratio of the amount of precipitant added to the injected water is .

7. The combined application method for sewage treatment according to claim 1, characterized in that: In step S5, the electrochemical sedimentation tank first removes cyanide and sulfide in the sewage by electrolysis, and then precipitates the pollutants in the sewage by the action of the electric field.

8. The combined application method for sewage treatment according to claim 1, characterized in that: In step S6, the mass ratio of the catalyst in the photocatalytic precipitation tank to the injected water is .

9. The combined application method for sewage treatment according to claim 1, characterized in that: In step S7, the photocatalytic sedimentation tank needs to undergo water quality testing before drainage to determine whether it is qualified. The water quality test determines whether the discharged water of the photocatalytic sedimentation tank meets the standards based on the concentration of ammonia in the discharged water, the concentration of the sum of all forms of phosphorus in the discharged water, and the concentration of the sum of all forms of nitrogen in the discharged water. Then: ； In the formula, Indicates the compliance coefficient of discharged water, Indicates the concentration of ammonia in the discharged water. It represents the total concentration of all forms of phosphorus in the discharged water. Represents the total concentration of all forms of nitrogen in the discharged water.

10. The combined application method for sewage treatment according to claim 9, characterized in that: when When , it means that the water finally discharged from the photocatalytic sedimentation tank meets the discharge standards of the wastewater treatment plant; when When , it means that the water finally discharged from the photocatalytic sedimentation tank does not meet the discharge standards of the wastewater treatment plant.

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