A disposal method for backwashing sludge in a groundwater source plant

Abstract

This invention relates to a method for disposing of backwash sludge from underground water treatment plants. It primarily addresses the problem of increased treatment costs and resource waste associated with existing methods of reusing large amounts of sludge generated during wastewater recovery at underground water treatment plants. The disposal method mainly includes the following steps: Step 1, solidifying the sludge; Step 2, adding the solidified sludge to a polyaluminum chloride product, followed by pressure filtration and sedimentation to obtain a compound product. This method for disposing of backwash sludge from underground water treatment plants can prepare a composite coagulant from the waste generated during production, which can then be reused in the coagulation and sedimentation process of domestic sewage treatment, saving resources and treatment costs.

Description

Technical fields:

[0001] This invention relates to the field of environmental protection technology, and in particular to a method for disposing of backwash sediment from an underground water treatment plant. Background technology:

[0002] During routine operation, the underground water treatment plant requires periodic backwashing of the filter tanks, generating backwash wastewater (containing a large amount of impurities). This backwash wastewater is currently stored in the plant's wastewater recovery tank. Over time, a large amount of sludge has accumulated at the bottom of the tank. This sludge cannot be discharged arbitrarily and must be treated before being transported off-site.

[0003] Currently, the commonly used methods for treating wastewater and sludge are either to transport them directly to qualified third-party environmental protection companies for disposal or to air-dry the sludge before transporting it off-site. This waste is often reused to make building materials. However, these methods increase the economic costs of waste disposal at water treatment plants. Furthermore, the waste contains a large amount of iron salts (a major component of coagulants), and using it solely for building materials represents a waste of resources compared to the waste itself. Summary of the Invention:

[0004] This invention aims to overcome the problems of increased treatment costs and resource waste caused by existing methods of reusing large amounts of sludge generated from wastewater recycling in underground water treatment plants. Instead, it provides a method for disposing of backwash sludge from underground water treatment plants. This method allows the waste generated during production to be processed into a composite coagulant, which can then be reused in the coagulation and sedimentation process of domestic sewage treatment, saving resources and treatment costs.

[0005] The present invention solves its problem through the following technical solution: a method for treating backwash sediment from an underground water source plant, comprising the following steps:

[0006] Step 1: Solidify the sludge;

[0007] Step 2: Add the solidified sludge to the polysilicon aluminum chloride product, and then after pressure filtration and sedimentation, the compound product is obtained.

[0008] Furthermore, the method for solidifying the sludge in step 1 is as follows:

[0009] Wastewater and sludge from the water source plant are dried and treated; then the dried sludge is collected and solidified.

[0010] Furthermore, the moisture content of the sludge after solidification in step 2 is ≤99%.

[0011] Furthermore, the mass ratio of the solidified sludge to the polysilicon aluminum chloride product in step 2 is 1:15-1:20.

[0012] Furthermore, the solidified sludge is mixed with the polysilicon aluminum chloride product at a temperature of 100°C.

[0013] Furthermore, in step 2, the pressure filtration and sedimentation method adopts plate and frame pressure filtration and natural sedimentation.

[0014] Compared with the above-mentioned background technology, the present invention has the following beneficial effects:

[0015] Combining waste with polysilicon aluminum chloride products can effectively leach out the iron salt components in the waste and enhance the coagulation treatment effect of the agent.

[0016] All technical indicators of the compounded agent meet the technical requirements of Daqing Oilfield Water Engineering Technology Co., Ltd.'s enterprise standard Q / DQSW 005-2021 "Qingshui Brand Polysilicon Aluminum Chloride".

[0017] The compounded agent of this invention was tested on-site at the South District Wastewater Treatment Plant under Daqing Beikong Water Group. When the dosage of the compounded agent was 40 mg / L, the compounded agent had a significant treatment effect on domestic sewage, and the SS (suspended solids content) and TP (total phosphorus content) of the treated sewage met the production requirements of the wastewater treatment plant. Detailed implementation method:

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to specific examples.

[0019] A method for disposing of backwash sediment from an underground water source plant involves adding solidified sludge (moisture content ≤99%) to polysilicon aluminum chloride product at a mass ratio of 1:15-1:20 during the production process of polysilicon aluminum chloride at a water purification agent company, under production conditions of 100℃. After the sludge is added to the polysilicon aluminum chloride product, the product is obtained after plate and frame filtration and natural sedimentation.

[0020] Example 1

[0021] Sludge and polyaluminum chloride were mixed at a ratio of 1:15, and then subjected to plate and frame filter press and natural sedimentation to obtain the mixed product. The mixed agent was tested, and the specific test results are shown in Table 1. The wastewater treatment effect of the mixed agent in Example 1 is shown in Table 2.

[0022] The compounded reagent was subjected to full testing according to the Q / DQSW 005-2021 standard "Qingshui Brand Polysilicon Aluminum Chloride". The technical indicators after testing are shown in Table 1.

[0023] Table 1

[0024]

[0025] As can be seen from Table 1, all technical indicators of the compounded agent meet the technical requirements of Q / DQSW005-2021 "Qingshui Brand Polysilicon Aluminum Chloride".

[0026] The compounded agent was tested on-site at the South District Wastewater Treatment Plant under Daqing Beikong Water Group. The treatment effect was determined when the dosage of the compounded agent was 40 mg / L, as shown in Table 2.

[0027] Table 2

[0028]

[0029] As shown in Table 2, the compounded agent has a significant treatment effect on domestic sewage, and the treated SS and TP levels meet the production requirements of the sewage treatment plant and comply with the sewage treatment plant discharge standards in the national standard GB8978-1996 (SS≤30mg / L, TP≤1.0mg / L).

[0030] Example 2

[0031] Sludge and polyaluminum chloride were mixed at a ratio of 1:16, and then subjected to plate and frame filter press and natural sedimentation to obtain the mixed product. The mixed agent was tested, and the specific test results are shown in Table 3. The wastewater treatment effect of the mixed agent in Example 2 is shown in Table 4.

[0032] Table 3

[0033]

[0034]

[0035] Table 4

[0036]

[0037] The data in Tables 3 and 4 show that the SS (suspended solids) level after wastewater treatment reached 14 mg / L, and the TP (total plasma) level reached 0.27 mg / L. Example 2 meets the relevant standards and wastewater treatment requirements in terms of both technical indicators and wastewater treatment effect, satisfying the national standard GB 8978-1996 wastewater treatment plant discharge standards (SS≤30 mg / L, TP≤1.0 mg / L).

[0038] Example 3

[0039] Sludge and polysilicon aluminum chloride were mixed at a ratio of 1:18. The mixed agent was tested, and the specific test results are shown in Table 5 below. The wastewater treatment effect of the mixed agent in Example 3 is shown in Table 6.

[0040] Table 5

[0041]

[0042]

[0043] Table 6

[0044]

[0045] As can be seen from the data in Tables 5 and 6, Example 3 meets the relevant standards and wastewater treatment requirements in terms of both technical indicators and wastewater treatment effect. It satisfies the wastewater treatment plant discharge standards (SS≤30mg / L, TP≤1.0mg / L) in National Standard GB 8978-1996.

[0046] Example 4

[0047] Sludge and polysilicon aluminum chloride were mixed at a ratio of 1:20. The mixed agent was tested, and the specific test results are shown in Table 7. The wastewater treatment effect of the mixed agent in Example 4 is shown in Table 8.

[0048] Table 7

[0049]

[0050] Table 8

[0051]

[0052] As can be seen from the data in Tables 7 and 8, Example 4 meets the relevant standards and wastewater treatment requirements in terms of both technical indicators and wastewater treatment effect. It satisfies the wastewater treatment plant discharge standards (SS≤30mg / L, TP≤1.0mg / L) in National Standard GB 8978-1996.

Claims

1. A method for treating backwash sediment from an underground water treatment plant, characterized in that: The process includes the following steps: Step 1: Solidifying the sludge; the sludge waste from the water source plant contains a large amount of iron salts; Step 2: Add the solidified sludge to the polysilicon aluminum chloride product, and then after pressure filtration and sedimentation, the compound product is obtained; The mass ratio of the solidified sludge to polysilicon aluminum chloride product is 1:15-1:20; The solidified sludge is mixed with polysilicon aluminum chloride product at a temperature of 100℃.

2. The method for disposing of backwash sediment from an underground water treatment plant according to claim 1, characterized in that: The method for solidifying the sludge in step 1 is as follows: natural sun drying, that is, drying the mixture of wastewater and sludge from the water source plant; and then collecting the dried sludge as solidified sludge.

3. The method for treating backwash sediment from an underground water treatment plant according to claim 1, characterized in that: The sludge solidified in step 2 has a moisture content of ≤99%.

4. The method for treating backwash sediment from an underground water treatment plant according to claim 1, characterized in that: In step 2, the filtration and sedimentation methods are plate and frame filtration and natural sedimentation.

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