Sludge filter pressing system with reduced consumption and improved standard

Abstract

This utility model relates to a sludge dewatering system that reduces costs and improves efficiency, belonging to the field of wastewater treatment technology. It includes a sludge storage tank, a sludge conditioning tank, and a plate and frame filter press. The inlet of the sludge storage tank is connected to both a secondary sedimentation tank and a coagulation sedimentation tank via pipelines. The outlet of the sludge storage tank is connected to the inlet of the sludge conditioning tank via a screw pump. The outlet of the sludge conditioning tank is connected to the inlet of the plate and frame filter press via a pipeline and a feed pump. The sludge conditioning tank is equipped with a conditioning mixer, a cationic PAM dosing pipe, and a conditioning tank feed pipe. The filtrate outlet of the plate and frame filter press is connected to the sludge inlet pipe of the sludge storage tank via a pipeline and a filtrate dosing pump. This utility model can reduce the cost of sludge dewatering and significantly improve the chloride ion content in the effluent, reducing the equipment corrosion rate of downstream enterprises. Simultaneously, it enables the secondary recovery and reuse of residual chemicals in the filtrate obtained from the plate and frame filter press.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology, and in particular to a sludge depressurization system that reduces energy consumption and improves standards. Background Technology

[0002] With increasingly stringent environmental standards for effluent quality, some wastewater treatment plants have gradually eliminated sludge thickening tanks, and the sludge dewatering system in wastewater treatment systems now employs a combination of a sludge thickener and a plate and frame filter press. For example... Figure 1 As shown, this is the processing flow of an existing sludge dewatering system. The excess sludge from the secondary sedimentation tank and the coagulated sludge from the coagulation sedimentation tank enter the sludge storage tank through the sludge discharge pipe. After a short stay, it is pumped into a sludge thickener using a screw pump. Cationic polyacrylamide (PAM) is added to the sludge thickener to complete the initial dewatering and thickening of the sludge. The sludge after initial dewatering and thickening flows by gravity to the sludge conditioning tank. In the sludge conditioning tank, other sludge conditioning agents such as ferric chloride are added and mixed evenly using the agitator in the sludge conditioning tank. Then, it is fed into the plate and frame filter press through the feed pump of the plate and frame filter press for filtration. After filtration, sludge with a moisture content of about 60% is formed. It is then transported out of the plant for landfill or waste incineration, etc., to complete the reduction of sludge volume or resource recycling.

[0003] In actual operation, especially in areas with water shortages, the effluent from wastewater treatment plants needs to be reused by enterprises as makeup water for circulating water. At this time, the ferric chloride conditioner added to the sludge dewatering system will cause the chloride ion concentration in the effluent to increase, thereby reducing the concentration ratio of circulating water and even causing equipment corrosion, which is not conducive to the reuse of effluent. In addition, the addition of ferric chloride and other conditioners to the sludge dewatering system will also increase the cost of sludge treatment and increase the consumption of auxiliary facilities.

[0004] In summary, existing sludge dewatering systems have the following problems: 1. The large dosage of sludge conditioners such as cationic polyacrylamide and ferric chloride used in sludge dewatering systems increases the cost of sludge dewatering. 2. When wastewater from wastewater treatment plants is reused as circulating water in enterprises, the high chloride ion content of the filter liquid increases the corrosion rate of downstream equipment, which is detrimental to wastewater reuse. Summary of the Invention

[0005] To solve the above-mentioned technical problems, this utility model provides a sludge dewatering system that reduces energy consumption and improves efficiency. The technical solution of this utility model is as follows:

[0006] A sludge dewatering system for reduced energy consumption and improved efficiency includes a sludge storage tank, a sludge conditioning tank, and a plate and frame filter press. The inlet of the sludge storage tank is connected to a secondary sedimentation tank and a coagulation sedimentation tank via pipelines. The outlet of the sludge storage tank is connected to the inlet of the sludge conditioning tank via a screw pump. The outlet of the sludge conditioning tank is connected to the inlet of the plate and frame filter press via a pipeline and a feed pump. The sludge conditioning tank is equipped with a conditioning mixer, a cationic PAM dosing pipe, and a conditioning tank feed pipe. The filtrate outlet of the plate and frame filter press is connected to the sludge inlet pipe of the sludge storage tank via a pipeline and a filtrate dosing pump. The screw pump, feed pump, and filtrate dosing pump are all electrically connected to a controller.

[0007] Optionally, a first sludge level gauge is installed on the sludge storage tank. The first sludge level gauge is electrically connected to the controller, and the first sludge level gauge is interlocked with the sludge discharge pumps of the secondary sedimentation tank and the coagulation sedimentation tank.

[0008] Optionally, the sludge conditioning tank is equipped with a second sludge level gauge, which is electrically connected to the controller and interlocked with the screw pump.

[0009] Optionally, a sawdust dosing pipe is installed on the sludge conditioning tank, and the sawdust dosing pipe is connected to a sawdust dosing pump.

[0010] Optionally, a lime dosing pipe is installed on the sludge conditioning tank, and the lime dosing pipe is connected to a lime dosing driver.

[0011] Optionally, two sludge conditioning tanks are provided, and the two sludge conditioning tanks are arranged side by side.

[0012] Optionally, the sludge conditioning tank is provided with an inspection port and a sampling port.

[0013] Optionally, the feed pump is a plunger pump.

[0014] All of the above optional technical solutions can be combined arbitrarily, and this utility model does not provide a detailed description of the structure after each combination.

[0015] The beneficial effects of this utility model through the above solution are as follows:

[0016] By directly connecting the outlet of the sludge storage tank to the sludge conditioning tank and relocating the cationic polyacrylamide dosing point to the conditioning tank, the dosage of cationic polyacrylamide can be significantly reduced, eliminating the need for ferric chloride dosing. This reduces sludge filtration costs and significantly improves the chloride ion content in the effluent, lowering equipment corrosion rates in downstream enterprises. Furthermore, by directly adding the filtrate from the plate and frame filter press to the sludge storage tank's inlet pipe, residual chemicals in the filtrate are recycled, further reducing the dosage of cationic polyacrylamide, improving the flocculation effect of the sludge-water mixture in the storage tank, and simultaneously lowering the water content of the sludge storage tank.

[0017] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the composition and structure of an existing sludge dewatering system designed to reduce energy consumption and improve standards.

[0019] Figure 2 This is a schematic diagram of the composition and structure of the sludge depressurization system for reducing energy consumption and improving standards provided in this embodiment of the utility model.

[0020] Figure 3 This is a schematic diagram of the composition and structure of the sludge conditioning tank in this utility model. Detailed Implementation

[0021] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.

[0022] like Figure 2 and Figure 3 As shown in the figure, the sludge dewatering system for reducing energy consumption and improving efficiency provided in this embodiment of the present invention includes a sludge storage tank 1, a sludge conditioning tank 2, and a plate and frame filter press 3. The inlet of the sludge storage tank 1 is connected to both the secondary sedimentation tank and the coagulation sedimentation tank via pipelines. The outlet of the sludge storage tank 1 is connected to the inlet of the sludge conditioning tank 2 via a screw pump. The outlet of the sludge conditioning tank 2 is connected to the inlet of the plate and frame filter press 3 via a pipeline and a feed pump. The sludge conditioning tank 2 is equipped with a conditioning mixer 4, a cationic PAM dosing pipe 5, and a conditioning tank feed pipe 6 (the outlet of the screw pump is connected to the conditioning tank feed pipe 6). The filtrate outlet of the plate and frame filter press 3 is connected to the sludge inlet pipe of the sludge storage tank 1 (the pipeline between the inlet of the sludge storage tank 1 and the secondary sedimentation tank and the coagulation sedimentation tank) via a pipeline and a filtrate dosing pump. The screw pump, the feed pump, and the filtrate dosing pump are all electrically connected to a controller.

[0023] By setting up a controller, automatic control of the screw pump, feed pump, and filter liquid dosing pump was achieved.

[0024] The mixing mixer 4 has a power of 7.5KW, a mixing diameter of 1500mm, a mixing speed of 58rpm, and is made of carbon steel lined with rubber. The screw pump is model BN35-6L, with a flow rate of 21-35m³ / h, a pressure of 4bar, and a speed of 224-361r / min. The plate and frame filter press 3 has a plate and frame power of 108Kw, a base dimension of 7900mm, a filtration area of ​​200m³, 77 plates, a pressing pressure of 13MPa, a filtration pressure of 10Kg / cm², and a back pressure of 30MPa.

[0025] Specifically, relative Figure 1 The existing sludge dewatering system shown in this utility model embodiment has the following two improvements: (1) The sludge-water mixture in the sludge storage tank 1 is directly pumped to the sludge conditioning tank 2 by a screw pump, and the cationic polyacrylamide pipeline dosing point (cationic PAM dosing pipe 5) is changed from the inlet end of the sludge thickener to the sludge conditioning tank 2; (2) The filtrate from the plate and frame filter press 3 is directly added to the sludge inlet pipe of the sludge storage tank 1, realizing the secondary recycling of residual agents in the filtrate obtained by the plate and frame filter press 3.

[0026] Figure 1 The sludge thickener in the sludge filter press system shown requires a large dosage of cationic polyacrylamide during operation. Its principle is to flocculate the sludge-water mixture in the sludge storage tank into larger flocs by adding a large amount of cationic polyacrylamide. These flocs flow through the pores of the filter belt under gravity, while the sludge with low moisture content is retained and enters the sludge conditioning tank. This embodiment of the invention directly connects the outlet of the sludge storage tank 1 to the sludge conditioning tank 2 and moves the cationic polyacrylamide dosing point to the conditioning tank 2. This significantly reduces the amount of cationic polyacrylamide required and eliminates the need for ferric chloride, thereby greatly improving the chloride ion content in the effluent and reducing the corrosion rate of downstream equipment. The principle involved here is that the plate and frame filter press 3 does not require a large size of sludge flocs; only slightly smaller flocs are needed to achieve sludge dewatering under mechanical pressure, with limited impact on the moisture content of the sludge cake.

[0027] In addition, the effluent from the plate and frame filter press 3 still contains some residual cationic polyacrylamide. By recycling this residual liquid in a secondary manner, that is, by adding the effluent to the sludge inlet pipe of the sludge storage tank 1 using a filtrate dosing pump, the excess sludge discharged from the secondary sedimentation tank and the coagulated sludge discharged from the coagulation sedimentation tank can be further flocculated, thereby improving the flocculation effect of the sludge-water mixture in the sludge storage tank 1 and reducing the moisture content of the sludge storage tank 1.

[0028] Furthermore, the secondary sedimentation tank is located above the sludge storage tank 1. In existing sludge dewatering systems, the secondary sedimentation tank discharges sludge into the sludge storage tank via a sludge discharge pump, which is not only energy-intensive but also detrimental to sludge sedimentation and concentration. This is because the sludge storage tank is 5m wide and 8m long, and the flow rate of the sludge discharge pump is greater than 120m³ / h, resulting in an upward flow velocity of >3m / h in the sludge storage tank. The sludge dewatering system provided by this invention replaces the sludge discharge pump with gravity discharge (pressure difference greater than 1.5m), with a discharge flow rate of approximately 40m³ / h. The corresponding upward flow velocity in the sludge storage tank is <1m / h, which is beneficial for sludge sedimentation and concentration.

[0029] Based on the above improvements, taking a wastewater treatment plant with a treatment capacity of 10,000 cubic meters per day as an example, the sludge depressurization system can save more than 424,300 yuan per year after renovation (of which the chemical accounts for more than 47%), and significantly improve the effluent quality of the wastewater treatment plant, with a 20.6% reduction in effluent chloride.

[0030] (1) Direct economic benefits

[0031]

[0032] Note: The above data is derived from the consumption and testing data of auxiliary materials of the municipal sewage treatment plant over a continuous period of 16 months.

[0033] (2) Indirect benefits

[0034] Extended equipment lifespan: Reduced wear and tear on equipment from corrosive chemicals in wastewater treatment plants, while lower chloride ion levels in effluent extend the lifespan of equipment in downstream water users (increased concentration ratio, resulting in greater water conservation).

[0035] Operational safety: Hazardous chemical management risks are reduced to zero, and the on-site operating environment is improved.

[0036] Reduced management costs: Simplified procurement and storage processes for hazardous chemicals.

[0037] Environmental benefits: Eliminating the use of iron salts, optimizing the structure of process chemicals, and promoting green production.

[0038] In one specific embodiment, a first sludge level gauge is installed on the sludge storage tank 1. The first sludge level gauge is electrically connected to a controller, and the first sludge level gauge is interlocked with the sludge discharge pumps of the secondary sedimentation tank and the coagulation sedimentation tank. The sludge discharge pumps of the secondary sedimentation tank and the coagulation sedimentation tank are also electrically connected to the controller. When the first sludge level gauge detects that the sludge level in the sludge storage tank 1 has risen to the overflow port of the sludge storage tank 1, the controller controls the sludge discharge pumps of the secondary sedimentation tank and the coagulation sedimentation tank to stop discharging sludge.

[0039] In one specific embodiment, the sludge conditioning tank 2 is equipped with a second sludge level gauge, which is electrically connected to a controller and interlocked with a screw pump. When the second sludge level gauge detects that the sludge level in the sludge conditioning tank 2 has risen to its overflow port, the controller controls the screw pump to stop feeding sludge, ensuring that the sludge conditioning tank 2 has sufficient sludge concentration.

[0040] In one specific embodiment, a sawdust addition pipe is installed on the sludge conditioning tank 2, and the sawdust addition pipe is connected to a sawdust addition pump. If the sludge is to be dried and incinerated, waste sawdust can be added to the sludge conditioning tank 2 through the sawdust addition pipe and the sawdust addition pump to increase the calorific value and dryness of the sludge.

[0041] In one specific embodiment, a lime dosing pipe is installed on the sludge conditioning tank 2, and the lime dosing pipe is connected to a lime dosing actuator. The lime dosing actuator can be a pneumatic conveying pump or a screw conveying pump. If the sludge dewatering system needs to supplement the alkalinity of the nitrification system, lime can be added to the sludge conditioning tank 2 through the lime dosing pipe and the lime dosing actuator to increase the alkalinity of the filtrate and the dryness of the sludge.

[0042] In one specific embodiment, two sludge conditioning tanks 2 are provided, and the two sludge conditioning tanks 2 are arranged side by side. The two sludge conditioning tanks 2 can work simultaneously, or one can be used while the other is on standby.

[0043] In one specific embodiment, the sludge conditioning tank 2 is provided with an inspection port and a sampling port to facilitate maintenance and sampling.

[0044] In one specific embodiment, the feed pump is a plunger pump. The plunger pump is model JJZSP-40C, with a power of 15Kw, a plunger stroke of 365mm, a plunger diameter of 300mm, a maximum pressure of 2.0MPa, a maximum displacement of 40m³ / h, a lubrication capacity of 500L, and an inlet / outlet diameter of DN100.

[0045] In summary, the sludge dewatering system with reduced consumption and improved performance provided by this embodiment can significantly reduce the dosage of cationic polyacrylamide for sludge dewatering, while eliminating the need for ferric chloride dosage, thus reducing sludge disposal costs. Simultaneously, it significantly reduces the chloride ion content in the effluent, improving the quality of reclaimed water.

[0046] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A sludge dewatering system for reducing energy consumption and improving efficiency, characterized in that, The system includes a sludge storage tank (1), a sludge conditioning tank (2), and a plate and frame filter press (3). The inlet of the sludge storage tank (1) is connected to the secondary sedimentation tank and the coagulation sedimentation tank through a pipeline. The outlet of the sludge storage tank (1) is connected to the inlet of the sludge conditioning tank (2) through a screw pump. The outlet of the sludge conditioning tank (2) is connected to the inlet of the plate and frame filter press (3) through a pipeline and a feed pump. The sludge conditioning tank (2) is equipped with a conditioning mixer (4), a cationic PAM dosing pipe (5), and a conditioning tank feed pipe (6). The filtrate outlet of the plate and frame filter press (3) is connected to the sludge inlet pipe of the sludge storage tank (1) through a pipeline and a filtrate dosing pump. The screw pump, the feed pump, and the filtrate dosing pump are all electrically connected to the controller.

2. The sludge dewatering system for reducing energy consumption and improving efficiency according to claim 1, characterized in that, The sludge storage tank (1) is equipped with a first sludge level gauge, which is electrically connected to the controller, and the first sludge level gauge is interlocked with the sludge discharge pumps of the secondary sedimentation tank and the coagulation sedimentation tank.

3. The sludge dewatering system for reducing energy consumption and improving standards according to claim 1, characterized in that, The sludge conditioning tank (2) is equipped with a second sludge level gauge, which is electrically connected to the controller and is interlocked with the screw pump.

4. The sludge dewatering system for reducing energy consumption and improving standards according to claim 1, characterized in that, The sludge conditioning tank (2) is equipped with a sawdust addition pipe, which is connected to a sawdust addition pump.

5. The sludge dewatering system for reducing energy consumption and improving standards according to claim 1, characterized in that, The sludge conditioning tank (2) is equipped with a lime dosing pipe, which is connected to a lime dosing driver.

6. The sludge dewatering system for reducing energy consumption and improving standards according to claim 1, characterized in that, There are two sludge conditioning tanks (2), and the two sludge conditioning tanks (2) are set up side by side.

7. The sludge dewatering system for reducing energy consumption and improving standards according to claim 1 or 6, characterized in that, The sludge conditioning tank (2) is equipped with an inspection port and a sampling port.

8. The sludge dewatering system for reducing energy consumption and improving standards according to claim 1, characterized in that, The feed pump is a plunger pump.

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