Circulating sewage pretreatment system of coupling pre-reactor

Abstract

The utility model discloses a circulating blow-down water pretreatment system of a coupling pre-reactor, which belongs to the field of sewage treatment and recycling and comprises a circulating blow-down water storage tank, a pre-reactor, a mechanical accelerated stirring clarification tank, a variable-porosity filter tank, a clean water tank and a medicament adding unit which are connected in sequence, the mechanical accelerated stirring clarification tank is also connected with the sludge treatment unit; circulating blow-off water from a circulating blow-off water storage pool enters the pre-reactor from the bottom through a circulating blow-off water lifting pump; effluent of the pre-reactor automatically flows into a mechanical accelerated stirring clarification tank; effluent of the mechanical accelerated stirring clarification tank enters a variable-porosity filter tank to be filtered; the filtered clear water enters a clear water tank to be stored, and is pumped to each recycling point; sludge generated by the mechanical accelerated stirring clarification tank enters a sludge treatment unit to be treated. According to the utility model, the problem of adding medicaments in the existing system is effectively solved, the full reaction of the medicaments and circulating blow-down water is ensured, and the effluent quality of the pretreatment system is more stable.

Description

Technical Field

[0001] The utility model relates to the technical field of sewage treatment and recycling, in particular to a circulating sewage pretreatment system coupled with a pre-reactor. Background Art

[0002] Circulating sewage accounts for a large proportion of power plant wastewater. In view of the increasingly stringent environmental impact assessment requirements and the country's requirements for wastewater resource utilization, treating and reusing circulating sewage is an important means for power plants to achieve zero wastewater discharge and efficient use of water resources.

[0003] Circulating sewage usually has the characteristics of high hardness, high alkalinity, high turbidity, and high organic matter content. It cannot be directly reused in other systems. Especially for the subsequent membrane treatment system, it is very easy to cause membrane clogging. Therefore, removing turbidity and hardness from circulating sewage is a prerequisite for recycling circulating sewage. The pretreatment of circulating sewage usually adopts the lime + sodium carbonate double alkali method for softening, coagulation clarification, and filtration processes, and is equipped with mechanical accelerated stirring clarification tanks, filter tanks, dosing, sludge disposal and other equipment. However, in actual operation, the hardness removal process requires the addition of two agents, lime and sodium carbonate. If they are added at the same time, the agents will react with each other, which will not only affect the treatment effect but also increase the consumption of agents. Some projects add lime to the pipeline and sodium carbonate to the machine pool, which can easily lead to insufficient reaction time and fail to meet the effluent water quality requirements. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a circulating sewage pretreatment system coupled with a pre-reactor, which effectively solves the problem of adding reagents in the existing system, ensures the full reaction of the reagents with the circulating sewage, and makes the effluent quality of the pretreatment system more stable.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0006] A circulating sewage pretreatment system coupled with a prereactor comprises a circulating sewage storage tank, a prereactor, a mechanical accelerated stirring clarifier, a variable pore filter, a clean water tank and a reagent dosing unit which are connected in sequence; the mechanical accelerated stirring clarifier is also connected to a sludge treatment unit; the reagent dosing unit adds reagents to the prereactor, the mechanical accelerated stirring clarifier and the variable pore filter; the circulating sewage from the circulating sewage storage tank enters the prereactor from the bottom through a circulating sewage lifting pump; the effluent of the prereactor flows into the mechanical accelerated stirring clarifier by gravity; the effluent of the mechanical accelerated stirring clarifier enters the variable pore filter for filtration; the clean water after filtration enters the clean water tank for storage and is pumped to various reuse points; the sludge generated by the mechanical accelerated stirring clarifier enters the sludge treatment unit for treatment.

[0007] A further improvement of the technical solution of the utility model is that: a lime dosing port and a bactericide dosing port are arranged on the pre-reactor.

[0008] A further improvement of the technical solution of the utility model is that a pH meter for monitoring the dosage of the reagent and a stirrer for fully mixing the reagent with water are arranged inside the pre-reactor.

[0009] A further improvement of the technical solution of the utility model is that a residual chlorine meter for controlling the dosage of the fungicide is arranged on the outlet pipe of the pre-reactor.

[0010] A further improvement of the technical solution of the utility model is that the residence time of the circulating sewage in the pre-reactor is 10-15 minutes.

[0011] A further improvement of the technical solution of the utility model is that a hardness meter and a turbidity meter for controlling the quality of the effluent water are arranged at the water outlet of the mechanical accelerated stirring clarification tank.

[0012] A further improvement of the technical solution of the utility model is that the reagent dosing unit includes a first dosing device for simultaneously adding lime and bactericide into the pre-reactor, a second dosing device for simultaneously adding sodium carbonate and coagulant into the mechanical accelerated stirring clarifier, a pipeline mixer for adding flocculant into the water inlet pipe of the mechanical accelerated stirring clarifier, and a third dosing device for adding concentrated sulfuric acid into the water inlet pipe of the variable pore filter.

[0013] A further improvement of the technical solution of the utility model is that: the sludge treatment unit includes a sludge thickening tank connected to the mechanical accelerated stirring clarification tank; one end of the sludge thickening tank is connected to the desulfurization pulping unit; the other end of the sludge thickening tank is connected to the dewatering machine.

[0014] Due to the adoption of the above technical solution, the technical progress achieved by the utility model is:

[0015] 1. The utility model sets a pre-reactor before the mechanical accelerated stirring clarifier to make lime and water fully mixed and reacted, which is beneficial to the removal of temporary hardness in water, improves the effluent water quality, and can avoid the mutual reaction between lime and sodium carbonate in the double alkali method, thereby saving the dosage of reagents and reducing the amount of sludge generated, which can not only save the consumption of reagents, but also reduce the cost of sludge disposal.

[0016] 2. The utility model sets a pH meter in the pre-reactor, which is beneficial to monitoring the reaction conditions of water quality and convenient for adjusting the dosage of the reagent.

[0017] 3. The utility model sets a residual chlorine meter on the outlet pipe of the pre-reactor, which is beneficial to control the dosage of the bactericide and prevent the influence of excessive dosage on the subsequent system.

[0018] 4. The utility model sets a hardness meter at the outlet of the mechanical accelerated stirring clarification tank, which can timely observe the hardness removal situation and provide a guarantee for ensuring the water quality of the outlet water.

[0019] 6. In the utility model, one end of the sludge thickening tank is connected to the desulfurization pulping unit, and the other end is connected to the dewatering machine; the sludge produced in the sludge thickening tank can be recycled to the desulfurization pulping unit, and can also be dehydrated in the centrifugal dewatering machine, and the mud water produced in the sludge thickening tank is recycled to the desulfurization pulping unit, saving the cost of sludge disposal. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a schematic structural diagram of a circulating sewage pretreatment system coupled with a pre-reactor provided in an embodiment of the utility model;

[0022] Among them, 1. circulating sewage storage tank; 2. pre-reactor; 3. mechanical accelerated stirring clarification tank; 4. variable pore filter; 5. clear water tank; 6. sludge thickening tank; 7. desulfurization pulping unit; 8. dewatering machine. DETAILED DESCRIPTION

[0023] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "several" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0026] The present invention is further described in detail below with reference to the accompanying drawings and embodiments:

[0027] like Figure 1 As shown, a circulating sewage pretreatment system coupled with a prereactor comprises a circulating sewage storage tank 1, a prereactor 2, a mechanical accelerated stirring clarifier 3, a variable pore filter 4, a clean water tank 5 and a reagent dosing unit which are connected in sequence; the mechanical accelerated stirring clarifier 3 is also connected to the sludge treatment unit; the reagent dosing unit can add corresponding reagents to the prereactor 2, the mechanical accelerated stirring clarifier 3 and the variable pore filter 4; the circulating sewage from the circulating sewage storage tank 1 enters the prereactor 2 from the bottom through the circulating sewage lifting pump; the effluent of the prereactor 2 flows into the mechanical accelerated stirring clarifier 3 by gravity; the effluent of the mechanical accelerated stirring clarifier 3 enters the variable pore filter 4 for filtration; the clean water after filtration enters the clean water tank 5 for storage and is pumped to various reuse points; the sludge generated by the mechanical accelerated stirring clarifier 3 enters the sludge treatment unit for treatment.

[0028] Furthermore, the pre-reactor 2 is provided with a lime dosing port and a fungicide dosing port.

[0029] Furthermore, the pre-reactor 2 is provided with a pH meter for monitoring whether the dosage of the reagent meets the reaction requirements and a stirrer for fully mixing the reagent with water.

[0030] Furthermore, a residual chlorine meter for controlling the dosage of the fungicide is provided on the outlet pipe of the pre-reactor 2, which is beneficial to controlling the dosage of the fungicide.

[0031] Furthermore, the residence time of the circulating sewage in the pre-reactor 2 is 10-15 minutes, which ensures that the lime and the bactericide in the circulating sewage are fully mixed to achieve the effect of removing temporary hardness and sterilizing.

[0032] Furthermore, a hardness meter and a turbidity meter for controlling the quality of the effluent water are provided at the water outlet of the mechanical accelerated stirring clarification tank 3 , so that the quality of the effluent water of the mechanical accelerated stirring clarification tank 3 can be controlled.

[0033] Furthermore, the reagent dosing unit includes a first dosing device for simultaneously adding lime and bactericide into the pre-reactor 2, a second dosing device for simultaneously adding sodium carbonate and coagulant into the mechanical accelerated stirring clarifier 3, a pipeline mixer for adding flocculant into the water inlet pipe of the mechanical accelerated stirring clarifier 3, and a third dosing device for adding concentrated sulfuric acid into the water inlet pipe of the variable pore filter 4.

[0034] Furthermore, the sludge treatment unit includes a sludge thickening tank 6 connected to the mechanical accelerated stirring clarifier 3; one end of the sludge thickening tank 6 is connected to the desulfurization pulping unit 7; and the other end of the sludge thickening tank 6 is connected to the dewatering machine 8. The sludge produced by the sludge thickening tank 6 can be recycled to the desulfurization pulping unit 7, and can also be dewatered in the centrifugal dewatering machine 8.

[0035] The specific processing steps of a circulating sewage pretreatment system coupled with a pre-reactor provided by the utility model are as follows:

[0036] (1) The circulating wastewater from the plant cooling tower is collected and stored in the circulating wastewater storage tank 1 and transported to the pre-reactor 2 by the circulating wastewater lifting pump.

[0037] (2) The circulating sewage enters the pre-reactor 2 from the bottom. The upper part of the pre-reactor 2 is provided with a lime dosing port and a fungicide dosing port to facilitate the first dosing device of the dosing unit to add lime and fungicide to the pre-reactor 2 at the same time. Lime is added to the circulating sewage to remove temporary hardness in the water, and fungicide is added to prevent the growth of microorganisms. After the circulating sewage fully reacts with the reagents (lime and fungicide) in the pre-reactor 2, it flows out from the upper part of the pre-reactor 2. A residual chlorine meter is provided on the outlet pipe of the pre-reactor 2 to control the dosage of the fungicide. A pH meter and a stirrer are provided in the pre-reactor 2. The pH meter is used to monitor whether the dosage of the reagents (lime and fungicide) meets the reaction requirements. The stirrer is used to fully mix the reagents (lime and fungicide) with water to shorten the reaction time. The residence time of the circulating sewage in the pre-reactor 2 is 10-15 minutes to achieve the effect of removing temporary hardness and sterilization.

[0038] (3) The effluent of the pre-reactor 2 flows into the mechanical accelerated stirring clarifier 3 by gravity. The flocculant is added into the water inlet pipe of the mechanical accelerated stirring clarifier 3 through the pipeline mixer. After being fully mixed, it enters the mechanical accelerated stirring clarifier 3. Sodium carbonate and coagulant aid are added into the mechanical accelerated stirring clarifier 3 through the second dosing device of the reagent dosing unit. Sodium carbonate is used to remove the permanent hardness in the water. The coagulant aid helps the precipitate to form large flocs, which is conducive to sedimentation. A pH meter is installed in the mechanical accelerated stirring clarifier 3 to facilitate the observation of the pH value in the water and control the dosage of sodium carbonate. A hardness meter and a turbidity meter are installed at the outlet pipe of the mechanical accelerated stirring clarifier 3 to monitor the effluent quality of the mechanical accelerated stirring clarifier 3. The dosage can also be adjusted through the hardness meter. The turbidity of the effluent of the mechanical accelerated stirring clarifier 3 is ≤5NTU, the suspended solids are ≤10mg / L, and the hardness meets the requirements of the subsequent system.

[0039] (4) The effluent from the mechanical accelerated stirring clarification tank 3 is adjusted by adding acid (concentrated sulfuric acid) and then enters the variable pore filter 4 for filtration treatment. After treatment, the turbidity of the produced water is guaranteed to be ≤1NTU and the suspended solids are ≤5mg / L. The filtered clean water enters the clean water tank 5 for storage and is pumped to various reuse points.

[0040] (5) The sludge produced by the mechanical accelerated stirring clarifier 3 enters the sludge thickening tank 6 for concentration. The concentrated sludge (water content ≤ 97%) is preferentially reused in the desulfurization pulping unit 7. If it cannot be reused, it can be dehydrated by the dewatering machine 8, the mud cake is sent out, and the water quality is reused.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A circulating sewage pretreatment system coupled with a prereactor, characterized in that: The invention comprises a circulating sewage storage tank (1), a pre-reactor (2), a mechanical accelerated stirring clarifier (3), a variable pore filter (4), a clean water tank (5) and a reagent dosing unit which are connected in sequence; the mechanical accelerated stirring clarifier (3) is also connected to a sludge treatment unit; the reagent dosing unit doses reagents to the pre-reactor (2), the mechanical accelerated stirring clarifier (3) and the variable pore filter (4); the circulating sewage from the circulating sewage storage tank (1) enters the pre-reactor (2) from the bottom through a circulating sewage lifting pump; the effluent of the pre-reactor (2) flows into the mechanical accelerated stirring clarifier (3) by gravity; the effluent of the mechanical accelerated stirring clarifier (3) enters the variable pore filter (4) for filtration; the clean water after filtration enters the clean water tank (5) for storage and is pumped to various reuse points; the sludge generated by the mechanical accelerated stirring clarifier (3) enters the sludge treatment unit for treatment.

2. The circulating sewage pretreatment system coupled with a pre-reactor according to claim 1, characterized in that: The pre-reactor (2) is provided with a lime dosing port and a fungicide dosing port.

3. The circulating sewage pretreatment system coupled with a pre-reactor according to claim 1, characterized in that: The pre-reactor (2) is provided with a pH meter for monitoring the dosage of the reagent and a stirrer for fully mixing the reagent with water.

4. The circulating sewage pretreatment system coupled with a pre-reactor according to claim 1, characterized in that: A residual chlorine meter for controlling the dosage of fungicide is provided on the water outlet pipe of the pre-reactor (2).

5. The circulating sewage pretreatment system coupled with a pre-reactor according to claim 1, characterized in that: The residence time of the circulating wastewater in the pre-reactor (2) is 10-15 minutes.

6. The circulating sewage pretreatment system coupled with a pre-reactor according to claim 1, characterized in that: A hardness meter and a turbidity meter for controlling the quality of the effluent are provided at the water outlet of the mechanical accelerated stirring clarification tank (3).

7. The circulating sewage pretreatment system coupled with a pre-reactor according to claim 1, characterized in that: The reagent dosing unit comprises a first dosing device for respectively dosing lime and bactericide into the pre-reactor (2), a second dosing device for respectively dosing sodium carbonate and coagulant into the mechanical accelerated stirring clarifier (3), a pipeline mixer for dosing flocculant into the water inlet pipe of the mechanical accelerated stirring clarifier (3), and a third dosing device for dosing concentrated sulfuric acid into the water inlet pipe of the variable pore filter (4).

8. The circulating sewage pretreatment system coupled with a pre-reactor according to claim 1, characterized in that: The sludge treatment unit comprises a sludge concentration tank (6) connected to the mechanical accelerated stirring clarifier (3); one end of the sludge concentration tank (6) is connected to a desulfurization pulping unit (7); and the other end of the sludge concentration tank (6) is connected to a dewatering machine (8).

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