Treatment device for activated sludge in pulping wastewater as well as treatment method and application thereof

Abstract

The invention belongs to the technical field of pulping wastewater treatment, and particularly relates to a treatment device for activated sludge in pulping wastewater and a treatment method and application thereof. Comprising the following steps: 1, active sludge enters a treatment device and is mixed with a bactericide from a bactericide pipeline in a first static mixer; 2, mixing the mixed solution in the step 1 with a sludge modifier from a sludge modifier pipeline in a second static mixer; 3, mixing the solution mixed in the step 2 with a ferrous sulfate solution from a ferrous sulfate pipeline in a third static mixer; and 4, mixing the solution mixed in the step 3 with a talcum powder solution from a talcum powder pipeline in a fourth static mixer. The sterilizing agent, the sludge modifier, the ferrous sulfate and the talcum powder are sequentially added, so that bacteria and microorganisms are effectively killed, the particle structure of the sludge is improved, the water filtering performance of the activated sludge is improved, the activated sludge is successfully converted into a production raw material of the corrugating base paper, and recycling and reusing of resources are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of pulping wastewater treatment, and in particular relates to a treatment device for activated sludge in pulping wastewater, a treatment method and an application thereof. Background Art

[0002] In the production process of domestic corrugated paper, waste cartons are the main production raw materials. After the pulping process, a large amount of pulping wastewater will be generated. These wastewaters need to be treated before they can be discharged to avoid pollution to the environment. At present, the treatment process of pulping wastewater usually includes multiple links such as inclined screen filtration, hydrolysis acidification, IC anaerobic reaction, activated sludge aeration treatment, secondary sedimentation tank sedimentation, Fenton oxidation treatment and final municipal sewage treatment.

[0003] During the aeration treatment of activated sludge, the chemical oxygen demand (COD) in sewage is effectively reduced through the degradation of microorganisms. However, a large amount of activated sludge is produced in this process. The main components of these activated sludges include bacteria, living microorganisms and corpses (about 40-50wt.%), fibers (about 10-15wt.%) and inorganic fillers (about 35-50wt.%). Due to its fine particles and poor fluidity, if the activated sludge is directly used as a raw material for corrugated paper production without treatment, the gaps in the paper machine felt will be blocked, thereby affecting the dehydration effect. During the operation of the paper machine, the dryness of the wet paper sheet will decrease, thereby affecting the speed of the paper machine and the drying capacity of the paper sheet in the drying section. The traditional method of treating activated sludge is mainly to use a filter press for filter pressing and dehydration. After the sludge is dehydrated to a moisture content of ≥50wt.%, it is then transported to the boiler for combustion treatment. However, since the activated sludge contains a large amount of fiber and inorganic filler components, if it is directly burned, it will lead to a waste of resources. At the same time, the combustion process will cause secondary pollution, bringing additional burden to the environment.

[0004] Therefore, there is an urgent need to develop a new activated sludge treatment method that can not only effectively treat the harmful components in the activated sludge, but also make full use of the valuable resources therein and avoid resource waste. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for treating activated sludge in pulping wastewater. By adding bactericides, sludge modifiers, ferrous sulfate and talcum powder in sequence, bacterial microorganisms can be effectively killed, the sludge particle structure can be improved, and the water filtration performance can be improved, thereby avoiding the problem of felt gap blockage caused by the operation of the papermaking machine, improving the operating efficiency of the papermaking machine, and successfully converting the activated sludge in the pulping wastewater into the production raw material of corrugated paper, thereby realizing the recovery and reuse of resources.

[0006] Another object of the present invention is to provide a treatment device used in a method for treating activated sludge in pulping wastewater and application of the treated activated sludge.

[0007] The technical solution adopted by the present invention is as follows: The method for treating activated sludge in pulping wastewater, the treatment device used therein, comprises an activated sludge feeding pipeline, the outlet of the activated sludge feeding pipeline is connected to a pulping tank, the activated sludge feeding pipeline is sequentially connected with a bactericide pipeline, a sludge modifier pipeline, a ferrous sulfate pipeline and a talcum powder pipeline, and the activated sludge feeding pipeline between the bactericide pipeline and the sludge modifier pipeline, between the sludge modifier pipeline and the ferrous sulfate pipeline, between the ferrous sulfate pipeline and the talcum powder pipeline, and between the talcum powder pipeline and the pulping tank are respectively provided with a first static mixer, a second static mixer, a third static mixer and a fourth static mixer; The method for treating activated sludge in pulping wastewater comprises the following steps: Step 1: The activated sludge enters the treatment device through the activated sludge feed pipeline and is mixed with the bactericide from the bactericide pipeline in the first static mixer; by introducing the bactericide, the living bacteria and microorganisms in the activated sludge are killed, the activity of organic matter is effectively reduced, and thus the corruption of the activated sludge is prevented; the amount of bactericide added is 1.2-1.6kg / t of absolute dry sludge; Step 2: Mix the solution mixed in step 1 with the sludge modifier from the sludge modifier pipeline in a second static mixer; utilize the polymerization effect of the sludge modifier to aggregate the activated sludge particles with a particle size of 5-10 μm into particles with a particle size of 30-50 μm; the amount of the sludge modifier added is 1.6-2.0 kg / t of absolute dry sludge; Step 3: Mix the solution mixed in step 2 with the ferrous sulfate solution from the ferrous sulfate pipeline in a third static mixer; by adding ferrous sulfate, the polymerization of activated sludge particles is further promoted to form large particles with a particle size of 200 μm, thereby improving the water filtration performance of the activated sludge and effectively avoiding the problem of clogging the gaps in the blanket; the amount of ferrous sulfate added is 60-100 kg / t of absolute dry sludge; Step 4: Mix the solution mixed in step 3 with the talc solution from the talc pipeline in the fourth static mixer and then enter the slurry tank; the amount of talc added is 100-200kg / t of absolute dry sludge.

[0008] Wherein, the bactericide is KURITA F-4010, and the sludge modifier is KURITA PD-1200, both of which are purchased from Kurita Industry (Dalian) Co., Ltd.

[0009] The preparation processes of the ferrous sulfate solution and the talcum powder solution can adopt the common processes in the industry, and the required equipment can also adopt the common devices in the industry. Since these preparation processes belong to the relatively mature technical scope and are not the core invention points of the present invention, they will not be described in detail in the specification.

[0010] The components of the activated sludge include: 40-50wt.% of bacteria, living microorganisms and corpses, 10-15wt.% of fibers and 35-50wt.% of inorganic fillers. The activated sludge is dried at 130°C for 4 hours to constant weight to obtain absolutely dry sludge.

[0011] The flow rate of the activated sludge in the activated sludge feeding pipeline is 1.5-1.8 m / s.

[0012] The flow rates of the bactericide, sludge modifier, ferrous sulfate solution and talcum powder solution are 3.5-4.6 m / s, 2.8-4.0 m / s, 2.0-3.0 m / s and 2.4-3.3 m / s respectively.

[0013] The concentration of the bactericide is 28-31wt.%.

[0014] The concentration of the sludge modifier is 50-60wt.%.

[0015] The concentration of the ferrous sulfate solution is 20-30wt.%.

[0016] The concentration of the talcum powder solution is 15-20wt.%.

[0017] The treatment device used in the method for treating activated sludge in pulping wastewater comprises an activated sludge feeding pipeline, the outlet of the activated sludge feeding pipeline is connected to a pulping tank, a bactericide pipeline, a sludge modifier pipeline, a ferrous sulfate pipeline and a talcum powder pipeline are sequentially connected to the activated sludge feeding pipeline, and a first static mixer, a second static mixer, a third static mixer and a fourth static mixer are respectively arranged on the activated sludge feeding pipeline between the bactericide pipeline and the sludge modifier pipeline, between the sludge modifier pipeline and the ferrous sulfate pipeline, between the ferrous sulfate pipeline and the talcum powder pipeline, and between the talcum powder pipeline and the pulping tank.

[0018] The activated sludge treated by the method for treating activated sludge in pulping wastewater is used for the production of corrugated paper.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention successfully converts the activated sludge generated in the pulping wastewater treatment process into the production raw material of corrugated base paper by sequentially adding a bactericide, a sludge modifier, ferrous sulfate and talcum powder. In the treatment process, not only the bactericide is used to kill bacterial microorganisms, but also the polymerization effect of the sludge modifier and ferrous sulfate and the viscosity reduction effect of talcum powder are cleverly utilized to gradually aggregate the activated sludge with small particles of 5-10 μm in size into large particles with a particle size of 200 μm, and reduce its viscosity, effectively avoiding the problem of clogging the gaps in the felt, significantly improving the operating performance of the paper machine, increasing the speed of the paper machine, and realizing the effective recovery and reuse of the activated sludge. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of the processing device used in the present invention; In the figure: 1. activated sludge feed pipeline; 2. slurry tank; 3. bactericide pipeline; 4. sludge conditioner pipeline; 5. ferrous sulfate pipeline; 6. talcum powder pipeline; 7. first static mixer; 8. second static mixer; 9. third static mixer; 10. fourth static mixer. DETAILED DESCRIPTION

[0021] The present invention is further described below with reference to the embodiments, but they do not limit the implementation of the present invention.

[0022] The raw materials used in the examples and comparative examples are conventional commercially available raw materials unless otherwise specified, and the process methods used in the examples and comparative examples are conventional methods in the art unless otherwise specified.

[0023] Some of the raw materials used in the examples and comparative examples are described as follows: Fungicide KURITA F-4010, purchased from Kurita Industry (Dalian) Co., Ltd.; Sludge modifier KURITA PD-1200 was purchased from Kurita Industry (Dalian) Co., Ltd.; Sizing agent CHSA-30 was purchased from Zhejiang Chuanhua Huayang Chemical Co., Ltd.

[0024] The treatment method for activated sludge in pulping wastewater described in the embodiments and comparative examples uses a treatment device such as Figure 1As shown, it includes an activated sludge feed pipeline 1, the outlet of the activated sludge feed pipeline 1 is connected to the pulping tank 2, and the activated sludge feed pipeline 1 is sequentially connected with a bactericide pipeline 3, a sludge modifier pipeline 4, a ferrous sulfate pipeline 5 and a talcum powder pipeline 6, and the activated sludge feed pipeline 1 is respectively provided with a first static mixer 7, a second static mixer 8, a third static mixer 9 and a fourth static mixer 10 between the bactericide pipeline 3 and the sludge modifier pipeline 4, between the sludge modifier pipeline 4 and the ferrous sulfate pipeline 5, between the ferrous sulfate pipeline 5 and the talcum powder pipeline 6, and between the talcum powder pipeline 6 and the pulping tank 2.

[0025] Example 1 The components of the activated sludge include: 40wt.% of bacteria, living microorganisms and their corpses, 10wt.% of fibers and 50wt.% of inorganic fillers.

[0026] The method for treating activated sludge in pulping wastewater comprises the following steps: Step 1: The activated sludge with a flow rate of 1.5 m / s enters the treatment device through the activated sludge feed pipeline 1, and is mixed with the bactericide (with a concentration of 28 wt.%) with a flow rate of 3.5 m / s from the bactericide pipeline 3 in the first static mixer 7; the amount of bactericide added is 1.2 kg / t of absolute dry sludge; Step 2: Mix the solution mixed in step 1 with the sludge modifier (concentration of 50 wt.%) at a flow rate of 2.8 m / s from the sludge modifier pipeline 4 in the second static mixer 8; the amount of the sludge modifier added is 1.6 kg / t of absolute dry sludge; Step 3: Mix the solution mixed in step 2 with a ferrous sulfate solution (concentration of 20 wt.%) with a flow rate of 2 m / s from the ferrous sulfate pipeline 5 in the third static mixer 9; the amount of ferrous sulfate added is 60 kg / t of absolute dry sludge; Step 4: The mixed solution in step 3 is mixed with a talcum powder solution (concentration of 15 wt.%) at a flow rate of 2.4 m / s from the talcum powder pipeline 6 in the fourth static mixer 10 and then enters the slurry tank 2. The amount of talcum powder added is 100 kg / t of absolute dry sludge.

[0027] Example 2 The components of the activated sludge include: 50wt.% of bacteria, living microorganisms and their corpses, 15wt.% of fibers and 35wt.% of inorganic fillers.

[0028] The method for treating activated sludge in pulping wastewater comprises the following steps: Step 1: The activated sludge with a flow rate of 1.8 m / s enters the treatment device through the activated sludge feed pipeline 1, and is mixed with the bactericide (with a concentration of 31 wt.%) with a flow rate of 4.6 m / s from the bactericide pipeline 3 in the first static mixer 7; the amount of bactericide added is 1.6 kg / t of absolute dry sludge; Step 2: Mix the solution mixed in step 1 with the sludge modifier (concentration 60 wt.%) at a flow rate of 4 m / s from the sludge modifier pipeline 4 in the second static mixer 8; the amount of the sludge modifier added is 2 kg / t of absolute dry sludge; Step 3: Mix the solution mixed in step 2 with a ferrous sulfate solution (with a concentration of 30 wt.%) at a flow rate of 3 m / s from the ferrous sulfate pipeline 5 in the third static mixer 9; the amount of ferrous sulfate added is 100 kg / t of absolute dry sludge; Step 4: The mixed solution in step 3 is mixed with a talcum powder solution (concentration of 20 wt.%) at a flow rate of 3.3 m / s from the talcum powder pipeline 6 in the fourth static mixer 10 and then enters the slurry tank 2. The amount of talcum powder added is 200 kg / t of absolute dry sludge.

[0029] Example 3 The components of the activated sludge include: 45wt.% of bacteria, living microorganisms and their corpses, 12wt.% of fibers and 43wt.% of inorganic fillers.

[0030] The method for treating activated sludge in pulping wastewater comprises the following steps: Step 1: The activated sludge with a flow rate of 1.6 m / s enters the treatment device through the activated sludge feed pipeline 1, and is mixed with the bactericide (with a concentration of 29 wt.%) with a flow rate of 4 m / s from the bactericide pipeline 3 in the first static mixer 7; the amount of bactericide added is 1.4 kg / t of absolute dry sludge; Step 2: Mix the solution mixed in step 1 with the sludge modifier (concentration of 55 wt.%) at a flow rate of 3.4 m / s from the sludge modifier pipeline 4 in the second static mixer 8; the amount of the sludge modifier added is 1.8 kg / t of absolute dry sludge; Step 3: Mix the solution mixed in step 2 with a ferrous sulfate solution (concentration of 25 wt.%) with a flow rate of 2.5 m / s from the ferrous sulfate pipeline 5 in the third static mixer 9; the amount of ferrous sulfate added is 80 kg / t of absolute dry sludge; Step 4: The mixed solution in step 3 is mixed with a talcum powder solution (concentration of 17 wt.%) at a flow rate of 2.8 m / s from the talcum powder pipeline 6 in the fourth static mixer 10 and then enters the slurry tank 2. The amount of talcum powder added is 150 kg / t of absolute dry sludge.

[0031] Comparative Example 1 Compared with Example 3, the dosage of the fungicide is reduced from 1.4 kg / t of absolute dry sludge to 0.5 kg / t of absolute dry sludge, and the rest is the same as Example 3.

[0032] Comparative Example 2 Compared with Example 3, the dosage of the sludge modifier is reduced from 1.8 kg / t of absolute dry sludge to 0.6 kg / t of absolute dry sludge, and the rest is the same as Example 3.

[0033] Comparative Example 3 Compared with Example 3, the dosage of ferrous sulfate is reduced from 80 kg / t of absolute dry sludge to 30 kg / t of absolute dry sludge, and the rest is the same as Example 3.

[0034] Comparative Example 4 Compared with Example 3, the amount of talcum powder used is reduced from 150 kg / t of absolute dry sludge to 50 kg / t of absolute dry sludge, and the rest is the same as Example 3.

[0035] The activated sludge treated in Examples 1-3 and Comparative Examples 1-4 was used to prepare corrugated paper, and the preparation method was as follows: The waste corrugated paper boxes are transported to the D-type hydraulic pulper through the chain plate for pulping, and the larger light and heavy impurities are removed in the process. Then, the pulp passes through the high-concentration desander, the external flow coarse screen, the low-concentration desander and the internal flow fine screen in turn to further remove the smaller light and heavy impurities, so as to obtain a relatively clean waste paper pulp. At this time, the pulp concentration is 1wt.%, and after dehydration and concentration treatment by the concentration multi-disc, the pulp with a concentration of 3wt.% is obtained and stored in the pulping tank.

[0036] Add 50kg / t of treated activated sludge to the slurry in the pulping tank, mix well and then lift it to the pre-papering tank, add white water to dilute it to a concentration of 1wt.%, enter the headbox for steady speed rectification, and then transport it to the paper machine, and go through the wire forming, press dehydration to a wet paper sheet dryness of 48wt.%, and further drying to a paper sheet dryness of 95wt.% in the drying section, and then send it to the sizing machine for impregnation with a sizing agent with a concentration of 10wt.% to enhance the ring compression strength of the corrugated base paper. After impregnation, the paper sheet dryness is 65wt.%, and it is sent to the drying section of the paper machine for further drying to a paper moisture content of 6wt.%, completing the preparation of the corrugated base paper.

[0037] The performance tests were performed on the corrugated paper prepared from the activated sludge treated in Examples 1-3 and Comparative Examples 1-4, respectively, and the test methods were as follows: Under the same paper machine speed condition, 120g / m 2 Corrugated paper: Refer to GB / T 462-2003 to test the dryness (wt.%) of wet paper sheets after pressing; Refer to GB / T 742-2003 to test the ash content (wt.%) of finished paper; The test results are shown in Table 1.

[0038] Table 1 Performance test results

[0039] It can be seen from the data in Table 1 that the wet paper dryness after pressing and the ash content of the corrugated base paper prepared in Examples 1-3 both meet the product quality standards (the quality standard for wet paper dryness after pressing is ≥50wt.%; the quality standard for ash content of the finished paper is 12-14wt.%).

[0040] In Comparative Examples 1-4, due to the adjustment of the amount of additives added during the activated sludge treatment process, the dryness of the wet paper sheets out of the press and the ash content of the finished corrugated paper were significantly reduced, which did not meet the product quality standards for corrugated paper.

Claims

1. A method for treating activated sludge in pulping wastewater, characterized in that: The treatment device used in the invention comprises an activated sludge feeding pipeline (1), the outlet of the activated sludge feeding pipeline (1) is connected to a pulping tank (2), a bactericide pipeline (3), a sludge modifier pipeline (4), a ferrous sulfate pipeline (5) and a talcum powder pipeline (6) are sequentially connected to the activated sludge feeding pipeline (1), and a first static mixer (7), a second static mixer (8), a third static mixer (9) and a fourth static mixer (10) are respectively arranged on the activated sludge feeding pipeline (1) between the bactericide pipeline (3) and the sludge modifier pipeline (4), between the sludge modifier pipeline (4) and the ferrous sulfate pipeline (5), between the ferrous sulfate pipeline (5) and the talcum powder pipeline (6), and between the talcum powder pipeline (6) and the pulping tank (2); The method for treating activated sludge in pulping wastewater comprises the following steps: Step 1: The activated sludge enters the treatment device through the activated sludge feed pipeline (1) and is mixed with the bactericide from the bactericide pipeline (3) in the first static mixer (7); the amount of bactericide added is 1.2-1.6 kg / t of absolute dry sludge; Step 2: Mix the solution mixed in step 1 with the sludge modifier from the sludge modifier pipeline (4) in a second static mixer (8); the amount of the sludge modifier added is 1.6-2.0 kg / t of absolute dry sludge; Step 3: Mix the solution mixed in step 2 with the ferrous sulfate solution from the ferrous sulfate pipeline (5) in a third static mixer (9); the amount of ferrous sulfate added is 60-100 kg / t of absolute dry sludge; Step 4: The solution mixed in step 3 is mixed with the talc solution from the talc pipeline (6) in the fourth static mixer (10) and then enters the slurry tank (2); the amount of talc added is 100-200 kg / t of absolute dry sludge; Wherein, the bactericide is KURITA F-4010; the sludge modifier is KURITA PD-1200; the activated sludge is dried to a constant weight to obtain absolutely dry sludge.

2. The method for treating activated sludge in pulping wastewater according to claim 1, characterized in that: The components of the activated sludge include: 40-50wt.% of bacteria, living microorganisms and their corpses, 10-15wt.% of fibers and 35-50wt.% of inorganic fillers.

3. The method for treating activated sludge in pulping wastewater according to claim 1, characterized in that: The flow rate of the activated sludge in the activated sludge feeding pipeline (1) is 1.5-1.8 m / s.

4. The method for treating activated sludge in pulping wastewater according to claim 1, characterized in that: The flow rates of the bactericide, sludge modifier, ferrous sulfate solution and talcum powder solution are 3.5-4.6 m / s, 2.8-4.0 m / s, 2.0-3.0 m / s and 2.4-3.3 m / s respectively.

5. The method for treating activated sludge in pulping wastewater according to claim 1, characterized in that: The concentration of the bactericide is 28-31wt.%.

6. The method for treating activated sludge in pulping wastewater according to claim 1, characterized in that: The concentration of the sludge modifier is 50-60wt.%.

7. The method for treating activated sludge in pulping wastewater according to claim 1, characterized in that: The concentration of the ferrous sulfate solution is 20-30wt.%.

8. The method for treating activated sludge in pulping wastewater according to claim 1, characterized in that: The concentration of the talcum powder solution is 15-20wt.%.

9. A treatment device used in the method for treating activated sludge in pulping wastewater according to any one of claims 1 to 8, characterized in that: The invention comprises an activated sludge feeding pipeline (1), the outlet of which is connected to a pulping tank (2), the activated sludge feeding pipeline (1) being connected in sequence to a bactericide pipeline (3), a sludge modifier pipeline (4), a ferrous sulfate pipeline (5) and a talcum powder pipeline (6), and the activated sludge feeding pipeline (1) being respectively provided with a first static mixer (7), a second static mixer (8), a third static mixer (9) and a fourth static mixer (10) between the bactericide pipeline (3) and the sludge modifier pipeline (4), between the sludge modifier pipeline (4) and the ferrous sulfate pipeline (5), between the ferrous sulfate pipeline (5) and the talcum powder pipeline (6), and between the talcum powder pipeline (6) and the pulping tank (2).

10. An application of activated sludge treated by the method for treating activated sludge in pulping wastewater according to any one of claims 1 to 8, characterized in that: Used in the production of corrugated paper.

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