Reclaimed water treatment system capable of effectively reducing blockage of filter element
By adding NaOH and PAC to the middle water before ultrafiltration, the system prevents filter core clogging by forming and filtering out gelatinous precipitates, enhancing the efficiency and reducing maintenance costs in the middle water treatment process.
Patent Information
- Application Number
- CN202421770875.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-24
- Publication Date
- 2025-07-11
- Estimated Expiration
- 2034-07-24
AI Technical Summary
The issue of filter core clogging in the middle water treatment system during the recycling of waste paper is prevalent due to the formation of Fe(OH)2 gelatinous bodies, which are difficult to manage with existing methods.
A system is introduced where NaOH and PAC are added to the middle water before it enters the immersed ultrafiltration unit, allowing for the formation of gelatinous precipitates that are then filtered out, reducing the likelihood of clogging in subsequent security filters by using a sequence of treatment units including a middle water tank, immersed ultrafiltration, manganese sand filter, security filter, reverse osmosis membrane, and reverse osmosis product tank.
This approach effectively reduces filter core clogging by maintaining Fe2+ levels below 0.1 mg/L, prolonging filter core lifespan and reducing maintenance costs.
Smart Images
Figure CN223087705U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of middle water reuse in papermaking, and more specifically, relates to a middle water treatment system that can effectively reduce the blockage of filter elements. Background Technique
[0002] During the process of recycling waste paper for papermaking, a large amount of wastewater containing pollutants such as fine cellulose, chemical additives, ink, pigments, and mechanical impurities is generated. Generally, after the wastewater is treated by primary physical and chemical methods and secondary biochemical methods, the pollutants will be greatly reduced, but still cannot meet the discharge standard requirements, and the composition is complex and the biodegradability is poor. The Fenton oxidation method is particularly suitable for treating organic wastewater that is difficult to biodegrade and difficult to treat by general chemical methods. On this basis, for the middle water reuse of the wastewater that meets the discharge standard, the Fenton oxidation method needs to use the reaction of H2O2 and FeSO4, which will generate a large amount of Fe 2+ dissolves in water. With the flow of the water body, the dissolved HCO3 in the water - gradually dissociates, the pH of the water body rises, and the Fe dissolved in the water 2+ reacts with OH - to generate Fe(OH)2 colloid, which causes and accelerates the problem that the filter element of the filter in the middle water treatment is easily blocked by the colloid. Content of the Utility Model
[0003] 1. Problem to be Solved
[0004] Aiming at the problem that the filter element of the filter in the middle water treatment is easily blocked by the colloid during the process of recycling waste paper for papermaking in the prior art, the utility model provides a middle water treatment system that can effectively reduce the blockage of the filter element. The utility model adds medicine to the middle water in advance through a medicine adding pipe and places the submerged ultrafiltration device in front. The middle water fully reacts during the flow in the water conveying pipeline, forms colloid precipitation, and then the submerged ultrafiltration device blocks and cleans the colloid in advance, so as to achieve the purpose of preventing the subsequent security filter element from being blocked by the colloid.
[0005] 2. Technical Solution
[0006] In order to solve the above problems, the technical solution adopted by the utility model is as follows:
[0007] A middle water treatment system that effectively reduces filter element blockage, including a middle water tank, a submerged ultrafiltration device, an ultrafiltration product water tank, a manganese sand filter tank, a manganese sand product water tank, a security filter, a reverse osmosis membrane device, and a reverse osmosis product water tank that are connected in sequence through a water conveyance pipeline; a chemical dosing pipe is externally connected to the water conveyance pipeline between the middle water tank and the submerged ultrafiltration device; after the middle water tank receives the middle water, NaOH and PAC are dosed into the middle water by the chemical dosing pipe, and then pumped into the submerged ultrafiltration device by a water pump. The ultrafiltration product water of the submerged ultrafiltration device enters the ultrafiltration product water tank, and then is pumped into the manganese sand filter tank by a manganese sand inlet water pump. The water produced by the manganese sand filter tank enters the manganese sand product water tank, and then is sent to the security filter by a reverse osmosis inlet water pump. The water passing through the security filter is then treated by the reverse osmosis membrane device and the produced water is introduced into the reverse osmosis product water tank.
[0008] A further technical solution is that the submerged ultrafiltration device is a submerged ultrafiltration membrane tank, and a self-cleaning filter is provided at its inlet.
[0009] A still further technical solution is that the reverse osmosis concentrated water of the reverse osmosis membrane device is sent to a reverse osmosis concentrated water tank for temporary storage and then sent to a Fenton system.
[0010] A still further technical solution is that the ultrafiltration membrane of the submerged ultrafiltration membrane tank is chemically cleaned and backwashed by the product water of the ultrafiltration product water tank, and the backwash wastewater is sent to a wastewater tank.
[0011] A still further technical solution is that air is introduced into both the submerged ultrafiltration device and the manganese sand filter tank through a blower.
[0012] 3. Beneficial effects
[0013] Compared with the prior art, the beneficial effects of the present utility model are as follows:
[0014] For the middle water treatment system of the present utility model that effectively reduces filter element blockage, PAC (poly aluminum chloride) is added in advance. By adding a chemical dosing pipe to the outlet pipeline of the ultrafiltration inlet water pump beside the middle water tank, and then using a metering pump to dose NaOH and PAC into the raw water, the pH of the raw water is adjusted to above 7.0, and the PAC dosing amount is 10 ppm. Through sufficient reaction during a certain pipeline flow, colloid precipitation is formed, which is blocked by the ultrafiltration membrane and removed through backwashing. At this time, the Fe 2+ ions in the ultrafiltration product water can reach 0.05 - 0.15 mg / L, and the Fe 2+ ions in the subsequent manganese sand product water are less than 0.1 mg / L, effectively reducing the situation of the colloid blocking the security filter element, delaying the cycle of filter element blockage, reducing the frequency of filter element replacement, and lowering the production cost. Description of the drawings
[0015] Figure 1 It is a schematic structural diagram of the middle water treatment system that effectively reduces filter element blockage for a specific embodiment;
[0016] Figure 2 Schematic diagram of the sewage treatment process for specific embodiments.
[0017] In the figure: 1, intermediate water tank; 2, self-cleaning filter; 3, submerged ultrafiltration device; 4, ultrafiltration product water tank; 5, manganese sand filter; 6, manganese sand product water tank; 7, reverse osmosis security filter; 8, reverse osmosis membrane device; 9, reverse osmosis product water tank; 10, fan; 11, reverse osmosis concentrated water tank; 12, wastewater tank; 13, Fenton system; 100, chemical addition pipe. Specific embodiments
[0018] The following further describes the present utility model in conjunction with specific embodiments.
[0019] Embodiment 1
[0020] The intermediate water treatment system of this embodiment that effectively reduces filter element blockage, as Figure 1 shown, includes an intermediate water tank 1, a submerged ultrafiltration device 3, an ultrafiltration product water tank 4, a manganese sand filter 5, a manganese sand product water tank 6, a security filter 7, a reverse osmosis membrane device 8, and a reverse osmosis product water tank 9 that are sequentially connected through a water conveyance pipeline; a chemical addition pipe 100 is externally connected to the water conveyance pipeline between the intermediate water tank 1 and the submerged ultrafiltration device 3; after the intermediate water tank 1 receives the intermediate water, NaOH and PAC are added to the intermediate water through the chemical addition pipe 100, and then it is pumped into the submerged ultrafiltration device 3 by a water pump. The ultrafiltration product water of the submerged ultrafiltration device 3 enters the ultrafiltration product water tank 4, and then is pumped into the manganese sand filter 5 by a manganese sand inlet water pump. The water produced by the manganese sand filter 5 enters the manganese sand product water tank 6, and then is sent to the security filter 7 through a reverse osmosis inlet water pump. The water passing through the security filter 7 is then treated by the reverse osmosis membrane device 8 and the produced water is introduced into the reverse osmosis product water tank 9.
[0021] The submerged ultrafiltration device 3 is a submerged ultrafiltration membrane tank, and its inlet is provided with a self-cleaning filter 2. The reverse osmosis concentrated water of the reverse osmosis membrane device 8 is sent to the reverse osmosis concentrated water tank 11 for temporary storage and then sent to the Fenton system 13. The ultrafiltration membrane of the submerged ultrafiltration membrane tank is chemically cleaned and backwashed with the water produced by the ultrafiltration product water tank 4, and the backwash wastewater is sent to the wastewater tank 12; air is introduced into both the submerged ultrafiltration device 3 and the manganese sand filter 5 through a fan 10. The fan 10 is generally a Roots blower.
[0022] The intermediate water treatment system of this embodiment that effectively reduces filter element blockage, in specific applications, the steps are as follows:
[0023] As Figure 2 shown, in steps one to eight:
[0024] Step one: The sewage discharged from the papermaking production line is removed of floating debris through a grille and enters the flocculation tank.
[0025] Step 2: Add coagulants and flocculants into the flocculation tank, and fully react with the pollutants in the sewage through a stirrer after stirring, then enter the primary sedimentation tank.
[0026] Step 3: In the primary sedimentation tank, the scum and sludge are removed by the surface skimmer and bottom sludge scraper, and the sewage enters the pre-acidification tank through a lift pump.
[0027] Step 4: The sewage stays in the pre-acidification tank, goes through two steps of hydrolysis and acidification, and then enters the anaerobic reactor.
[0028] Step 5: In the anaerobic reactor, anaerobic reaction is carried out by anaerobic bacteria (mainly methanogens) to decompose the pollutants in the sewage, generating biogas, and the sewage enters the aerobic SBR tank; SBR (Sequencing Batch Reactor Activated Sludge Process).
[0029] Step 6: The sewage undergoes cyclic reactions in the aerobic SBR tank through seven stages, namely: static water inlet, inlet stirring, inlet aeration, aeration stirring, stirring reaction, static sedimentation, and surface decantation. The activated sludge in the SBR tank further removes the pollutants in the sewage under sufficient aeration, and then enters the Fenton reaction tank.
[0030] Step 7: The sewage enters the Fenton reaction tank. First, the pH value of the sewage is adjusted to the optimal range required for the Fenton reaction (between pH 3.5 - 4.5) by adding concentrated sulfuric acid, and then ferrous sulfate FeSO4 and hydrogen peroxide H2O2 are added. Hydroxyl radicals are generated through the Fenton reaction (at the same time, Fe 3+ and Fe 2+ are generated and dissolved in water), which destroys the organic matter structure that is difficult to treat by both front-end physical and chemical and biochemical methods. Then, the pH is backfilled by adding sodium hydroxide, and a flocculant is added to flocculate and precipitate the destroyed pollutants. Through the inclined plate sedimentation tank, the sludge sinks and is removed, and the clear water enters the sand filter tank through the overflow port.
[0031] Step 8: The sewage passes through the sand filter tank to remove visible suspended solids, enters the intermediate water tank 1, and finally is discharged up to standard through the outfall.
[0032] As Figure 1 shown, in Steps 9 to 12:
[0033] Step 9: In the up-to-standard discharged wastewater in the intermediate water tank 1, Fe 2+The ion content is about 0.5 - 1.3 mg / L. Through the chemical dosing pipe 100, and then using a metering pump to add NaOH and PAC into the reclaimed water in the water conveyance pipeline, the pH of the reclaimed water is adjusted to above 7.0. The dosage of PAC is 10 ppm. It is pumped into the submerged ultrafiltration membrane tank through the ultrafiltration feed pump. A self-cleaning filter 2 is installed at the inlet of the membrane tank, with a filtration accuracy of 500 microns, which is used to remove larger impurities and avoid scratching the ultrafiltration membrane in the ultrafiltration membrane tank. The ultrafiltration product water pump extracts the water in the membrane tank. The water permeates through the ultrafiltration membrane, while the pollutants are retained on the surface of the ultrafiltration membrane. At this time, the dissolved Fe 2+ ions and tiny other pollutants also pass through the ultrafiltration membrane, and the Fe 2+ ion content is about 0.3 - 1.0 mg / L.
[0034] Step ten: The ultrafiltration product water enters the ultrafiltration product water tank 4, and then is pumped into the manganese sand filter tank 5 through the manganese sand feed pump. The Fe 2+ ions in the water react with the manganese sand to produce Fe 3+ ions, and then react with OH- in the water to produce Fe(OH)3 colloid. At this time, the Fe 2+ ion content is about 0.05 - 0.20 mg / L.
[0035] Step eleven: The water produced by the manganese sand filter tank 5 enters the manganese sand product water tank 6, and then is sent to the reverse osmosis membrane system through the reverse osmosis feed pump. A security filter 7 with a precision of 5 microns is installed in front of the reverse osmosis membrane, which intercepts most of the colloids and other pollutants. (The filter element in the security filter needs to be replaced after intercepting a certain amount of pollutants)
[0036] Step twelve: The water passing through the security filter 7 finally passes through the reverse osmosis membrane device (8) and the treated production water is introduced into the reverse osmosis product water tank (9). The production water in the reverse osmosis product water tank (9) becomes pure water with extremely low pollutant indicators.
[0037] The reclaimed water treatment system of this embodiment that can effectively reduce the blockage of the filter element adds PAC (poly aluminum chloride) in advance in step nine. By adding a chemical dosing pipe 100 on the water conveyance pipeline at the outlet of the ultrafiltration feed pump beside the intermediate water tank 1, and then using a metering pump to add NaOH and PAC into the reclaimed water, the pH of the reclaimed water is adjusted to above 7.0. The dosage of PAC is 10 ppm. During the flow through a certain pipeline, it reacts fully to form a colloidal precipitate, which is blocked by the ultrafiltration membrane and the colloidal precipitate is removed through backwashing. At this time, the Fe 2+ ion content in the ultrafiltration product water can reach 0.05 - 0.15 mg / L, and the Fe 2+ ion content in the subsequent manganese sand product water is less than 0.1 mg / L. While effectively treating the quality of the reclaimed water, it effectively reduces the situation of the colloids blocking the filter element of the security filter 7.
[0038] The reclaimed water treatment system in this embodiment can effectively reduce the blockage of the filter element. First, NaOH is added through the dosing pipe 100 to increase the pH value of the water body, then PAC is added through the dosing pipe 100 to cause the colloid in the water to flocculate. Finally, by using the interception function of the ultrafiltration membrane, the substances that block the security filter are precipitated in advance, and the ultrafiltration membrane is easy to clean, with little impact on its own operation. In the water quality treated by the Fenton system, the Fe 2+ ion content is about 0.5 - 1.3 mg / L. Through this reclaimed water treatment system, the Fe 2+ ion in the water quality is reduced to 0.05 - 0.15 mg / L; it also effectively reduces the situation where the colloid blocks the filter element 7 of the security filter, and saves the operation cost of the reclaimed water system.
[0039] The examples described in this utility model are only descriptions of the preferred embodiments of the utility model, and do not limit the concept and scope of the utility model. Without departing from the design idea of the utility model, various deformations and improvements made by those skilled in the art to the technical solutions of the utility model shall fall within the protection scope of the utility model.
Claims
1. A middle water treatment system that can effectively reduce the clogging of filter elements, characterized in that: It includes a middle water tank (1), a submerged ultrafiltration device (3), an ultrafiltration water production tank (4), a manganese sand filter (5), a manganese sand water production tank (6), a security filter (7), a reverse osmosis membrane device (8) and a reverse osmosis water production tank (9) that are connected in sequence through a water conveyance pipeline; a chemical dosing pipe (100) is externally connected to the water conveyance pipeline between the middle water tank (1) and the submerged ultrafiltration device (3).
2. The reclaimed water treatment system for effectively reducing the blockage of the filter element according to claim 1, characterized in that: The submerged ultrafiltration device (3) is a submerged ultrafiltration membrane tank, and a self-cleaning filter (2) is provided at its inlet.
3. The reclaimed water treatment system for effectively reducing the clogging of the filter element according to claim 2, wherein: The reverse osmosis concentrated water of the reverse osmosis membrane device (8) is sent to the reverse osmosis concentrated water tank (11) for temporary storage and then sent to the Fenton system (13).
4. The reclaimed water treatment system for effectively reducing the clogging of the filter element according to claim 2, wherein: The ultrafiltration membrane of the submerged ultrafiltration membrane tank is subjected to chemical cleaning and backwashing with the water produced by the ultrafiltration water production tank (4), and the backwashing wastewater is sent to the wastewater tank (12).
5. The reclaimed water treatment system for effectively reducing the blockage of the filter element according to any one of claims 1 to 4, characterized in that: In the submerged ultrafiltration device (3) and the manganese sand filter (5), air is introduced through a blower (10).