Paper mill high-salt reclaimed water recycling treatment device

Abstract

The invention discloses a paper mill high-salt reclaimed water reuse treatment device, and belongs to the technical field of paper mill high-salt reclaimed water reuse treatment, the paper mill high-salt reclaimed water reuse treatment device comprises a reclaimed water collection pool, a manganese sand filter, a clean water pool, a self-cleaning filter, a UF system and a UF water production pool which are sequentially connected through pipelines, and an outlet of the UF water production pool is connected with a primary concentration RO device through a pipeline; the second-stage concentration RO device comprises a second-stage RO concentration membrane and a second-stage RO concentrated water tank; the second-stage RO concentrated water tank is sequentially connected with a hardness removal reaction tank, a hardness removal coagulation tank, a hardness removal flocculation tank, a softening clarification tank, a tubular ultrafiltration membrane, a tubular ultrafiltration water producing tank, a softener, a softened water tank, a third-stage security filter, a third-stage concentration DTRO device, a concentrated brine collecting tank, an MVR evaporation device and a condensate water tank through pipelines. The system is used for recycling the high-salt reclaimed water of the paper mill, and has the advantages of low operation cost, good use effect, small occupied area, large water recycling amount, good water outlet effect and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of recycling and treating high-salinity reclaimed water in a paper mill, and in particular relates to a recycling and treating device for high-salinity reclaimed water in a paper mill. Background Art

[0002] The papermaking industry is an industry with large water consumption and large sewage discharge. "Energy conservation, emission reduction, and development of circular economy" are imperative. A large amount of organic matter and chemical substances in wastewater will lead to eutrophication of water bodies, promote the growth of algae, and pose a serious threat to the survival of fish and other aquatic organisms. At the same time, aquatic plants will die due to insufficient oxygen content in the water, further destroying the ecological balance of the water area. In addition, paper mill wastewater discharge will cause serious soil pollution. Heavy metals and organic matter in wastewater will penetrate into the soil, affect the physical and chemical properties and biological activity of the soil, lead to a decrease in soil fertility, and then have a destructive effect on agricultural production. The polluted land will no longer be suitable for growing crops, and will also indirectly pollute groundwater. Harmful substances in wastewater will enter water sources such as tap water and groundwater, affecting water quality and affecting human health. Polluted water sources can no longer be used as drinking water and industrial water, and will also destroy the balance of the ecosystem.

[0003] Wastewater discharged from paper mills is extremely harmful to human health. Harmful substances in wastewater can harm human health through skin contact, respiratory inhalation, and digestive tract ingestion. Long-term exposure to these harmful substances may cause skin inflammation, respiratory tract infection, and even serious diseases such as malignant tumors. In addition, the noise generated by wastewater discharge also interferes with the normal lives of surrounding residents.

[0004] As one of the most important manufacturing industries in the world, wastewater treatment in the modern papermaking industry has become the focus of the industry. Modern paper mills pay more and more attention to wastewater discharge control, which mainly comes from pulping, bleaching, dyeing and other production processes. In order to effectively control wastewater discharge, paper mills need to take a series of treatment measures, such as primary treatment, secondary treatment, tertiary treatment, etc. At the same time, it is also necessary to strengthen the supervision of wastewater discharge and reuse technology to achieve the recycling of paper mill wastewater. Summary of the invention

[0005] The present invention overcomes the deficiencies of the prior art and provides a high-salinity reclaimed water recycling treatment device for a paper mill to solve the problems existing in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a high-salinity water recycling treatment device for a paper mill, comprising

[0007] A reclaimed water collection tank, a manganese sand filter, a clear water tank, a self-cleaning filter, a UF system and a UF water production tank are sequentially connected by pipelines, and the outlet of the UF water production tank is connected to a primary RO concentration device through a pipeline, and the primary RO concentration device includes a primary security filter, a primary RO concentration membrane and a primary RO concentrated water tank that are sequentially connected by pipelines;

[0008] A secondary RO concentrating device, the secondary RO concentrating device comprises a secondary RO concentrating membrane and a secondary RO concentrated water tank, the primary RO concentrated water tank is connected to the secondary RO concentrating membrane via a secondary security filter;

[0009] The secondary RO concentrated water tank is sequentially connected by pipelines with a hardness removal reaction tank, a hardness removal coagulation tank, a hardness removal flocculation tank, a softening clarification tank, a tubular ultrafiltration membrane, a tubular ultrafiltration water production tank, a softener, a softened water tank, a three-stage security filter, a three-stage concentrated DTRO device, a concentrated brine collection tank, an MVR evaporation device and a condensation water tank.

[0010] In a preferred embodiment of the present invention, it also includes a reuse water pool, and the water outlet of the first-level RO concentrating membrane, the water outlet of the second-level RO concentrating membrane, the water outlet of the third-level concentrating DTRO device, the water outlet of the MVR evaporation device and the water outlet of the condensation water tank are all connected to the reuse water pool through pipelines.

[0011] In a preferred embodiment of the present invention, it also includes a sludge tank, and the sewage outlet of the manganese sand filter, the sewage outlet of the self-cleaning filter, the sewage outlet of the UF system and the sewage outlet of the softening and clarification tank are all connected to the sludge tank through pipelines.

[0012] In a preferred embodiment of the present invention, a sludge dewatering machine is provided at the end of the sludge pool to dewater the sludge.

[0013] In a preferred embodiment of the present invention, the primary RO concentrating membrane and the secondary RO concentrating membrane are both anti-pollution membranes.

[0014] In a preferred embodiment of the present invention, the UF system uses a UF backwash pump for backwashing, and 10% hydrochloric acid or 10% sodium hypochlorite is added during the backwashing process every 3-7 days.

[0015] In a preferred embodiment of the present invention, a reducing agent with an effective content of 5%-10%, an antiscalant with an effective content of 5%-15%, and a non-oxygen bactericide with an effective content of 100% are added to the UF water production tank, the first-level RO concentrated water tank, and the second-level RO concentrated water tank, and the non-oxygen bactericide is added intermittently and regularly.

[0016] In a preferred embodiment of the present invention, the hardness removal reaction tank, the hardness removal coagulation tank, the hardness removal flocculation tank and the softening clarification tank are all reaction tanks made of carbon steel lining FRP material.

[0017] In a preferred embodiment of the present invention, a 30% sodium carbonate solution and a 30% sodium hydroxide solution are added to the hardness removal reaction tank to adjust the pH of the wastewater to 10-11.5;

[0018] A PAC solution with an effective Al2O3 content of 10% is added into the de-hardening coagulation tank;

[0019] A 0.1% concentration of anionic PAM solution is added into the hardness removal flocculation tank.

[0020] In a preferred embodiment of the present invention, the softener is a reactor with a carbon steel rubber lining and a 1200 mm thick softening resin filled therein, and a 30% hydrochloric acid solution or a 30% sodium hydroxide solution is added into the softener to adjust the pH of the wastewater to 7.

[0021] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0022] The high-salt reclaimed water recycling treatment device for a paper mill of the present invention is used for recycling high-salt reclaimed water for a paper mill, and has the advantages of low operating cost, good use effect, small footprint, large amount of recycled water, good water output effect, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0024] Figure 1 A flowchart of a preferred embodiment of the present invention; DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0026] This embodiment provides a paper mill high-salt reclaimed water reuse treatment device, which is used for paper mill high-salt reclaimed water reuse treatment, and has the advantages of low operating cost, good use effect, small footprint, large reuse water volume, and good water output effect.

[0027] like Figure 1As shown, the high-salt recycled water reuse treatment device of the paper mill of this embodiment includes a recycled water collection tank, a manganese sand filter, a clean water tank, a self-cleaning filter, a UF system and a UF water production tank which are sequentially connected by pipelines. The outlet of the UF water production tank is connected to a primary concentration RO device through a pipeline. The primary concentration RO device includes a primary security filter, a primary RO concentration membrane and a primary RO concentrated water tank which are sequentially connected by pipelines.

[0028] In the present embodiment, the high-salt recycled water reuse treatment device of the paper mill also includes a secondary RO concentrating device, which includes a secondary RO concentrating membrane and a secondary RO concentrated water tank. The primary RO concentrated water tank is connected to the secondary RO concentrating membrane through a secondary security filter. The secondary RO concentrated water tank is connected in sequence through pipelines to a hardness removal reaction tank, a hardness removal coagulation tank, a hardness removal flocculation tank, a softening clarification tank, a tubular ultrafiltration membrane, a tubular ultrafiltration water production tank, a softener, a softening water tank, a third-level security filter, a third-level concentrating DTRO device, a brine collection tank, an MVR evaporation device and a condensation water tank. The primary RO concentrating membrane and the secondary RO concentrating membrane of the present embodiment are both anti-pollution membranes, which have the advantages of being anti-pollution, not afraid of clogging, flushable and not easy to break, and are conducive to operation.

[0029] Furthermore, the self-cleaning filter of the present embodiment is a filter with a shell made of SS316 material and a filtration accuracy of 100μm. Its accessories include SS316 steel brushes, electric motors, differential pressure switches, and electric valves. The first-level safety filter, the second-level safety filter, and the third-level safety filter are all safety filters with a shell made of SS316 material. They have built-in PP filter elements and a filtration accuracy of 5μm.

[0030] Specifically, the UF system of this embodiment uses a UF backwash pump for backwashing, and 10% hydrochloric acid or 10% sodium hypochlorite is added during the backwashing process every 3-7 days. A reducing agent with an effective content of 5%-10%, an antiscalant with an effective content of 5%-15%, and a non-oxygen bactericide with an effective content of 100% are added to the UF production water tank, the primary RO concentrated water tank, and the secondary RO concentrated water tank. The non-oxygen bactericide is added intermittently and regularly.

[0031] In this embodiment, the high-salt recycled water reuse treatment device of the paper mill also includes a reuse water pool and a sludge pool. The water outlet of the first-level RO concentrating membrane, the water outlet of the second-level RO concentrating membrane, the water outlet of the third-level concentrating DTRO device, the water outlet of the MVR evaporation device and the water outlet of the condensation water tank are all connected to the reuse water pool through pipes, and the sewage outlet of the manganese sand filter, the sewage outlet of the self-cleaning filter, the sewage outlet of the UF system and the sewage outlet of the softening clarification tank are all connected to the sludge pool through pipes. A sludge dewatering machine is provided at the end of the sludge pool to dehydrate the sludge.

[0032] Furthermore, the hardness removal reaction tank, hardness removal coagulation tank, hardness removal flocculation tank and softening clarification tank of this embodiment are all reaction tanks with carbon steel lining FRP material. 30% concentration of sodium carbonate solution and 30% concentration of sodium hydroxide solution are added to the hardness removal reaction tank to adjust the pH of the wastewater to 10-11.5; PAC solution with an effective Al2O3 content of 10% is added to the hardness removal coagulation tank; 0.1% concentration of anionic PAM solution is added to the hardness removal flocculation tank. The softener is a reactor with a carbon steel lining rubber filled with 1200mm softening resin. 30% concentration of hydrochloric acid solution or 30% concentration of sodium hydroxide solution is added to the softener to adjust the pH of the wastewater to 7.

[0033] In actual use, the high-salt reclaimed water recycling treatment device for a paper mill of this embodiment is collected in the reclaimed water collection pool, and then filtered through a manganese sand filter for suspended matter, solid particles and iron ions, and then enters a self-cleaning filter to prevent large particles from entering the subsequent units. After passing through the self-cleaning filter, it enters the UF system, which is mainly used as a pretreatment device for a reverse osmosis device. Before entering the primary security filter, a reducing agent, a non-oxygen bactericide and an antiscalant need to be added to prevent the primary RO concentration membrane from scaling and fouling. After entering the primary security filter, particles larger than 5 μm are mainly retained to prevent fine particles from entering the high-pressure pump and the primary RO concentration membrane and scratching the membrane surface. After that, it enters the secondary concentration RO device, which mainly removes the ion range and small molecular weight organic matter in the filtrate. The water produced by the primary RO concentration membrane enters the reuse water pool, and the concentrated water produced by the primary RO concentration membrane enters the primary RO concentrated water pool. Before the concentrated water enters the secondary security filter, non-oxygen bactericides and scale inhibitors need to be added to prevent the secondary RO concentration membrane from scaling and fouling. After the concentrated water enters the secondary security filter, it mainly intercepts particles larger than 5μm to prevent fine particles from entering the high-pressure pump and the secondary RO concentration membrane and scratching the membrane surface. The water produced by the secondary RO concentration membrane enters the reuse water pool, and the concentrated water of the secondary RO concentration membrane enters the secondary RO concentrated water pool, and then enters the hardness removal reaction tank. Sodium hydroxide and sodium carbonate are added to make the calcium ions and magnesium ions in the water react chemically. After entering the hardness removal coagulation tank for coagulation reaction, it enters the hardness removal flocculation tank for flocculation reaction, and then enters the softening clarification tank for precipitation. The supernatant of the softening clarification tank enters the tubular ultrafiltration membrane. The tubular ultrafiltration membrane separates and removes a large amount of organic matter, acid and alkali, heavy metal ions, salt, surfactants, catalysts and other substances in the wastewater. Then, after entering the tubular ultrafiltration water production tank, it enters the softener to further remove calcium ions and magnesium ions in the water to achieve the purpose of softening. Secondly, sodium hydroxide or hydrochloric acid is added to the softener to adjust the PH change. After entering the softening water tank, non-oxygen bactericides and scale inhibitors need to be added to prevent scaling of the DTRO membrane. The risk of fouling and clogging is eliminated. The three-stage security filter mainly intercepts particles larger than 5μm to prevent fine particles from entering the high-pressure pump and DTRO membrane assembly and scratching the membrane surface. The three-stage concentrated DTRO device mainly separates water molecules from pollutants in high-concentration sewage, thereby purifying sewage. The water produced by the three-stage concentrated DTRO device enters the reuse water pool, and the concentrated water of the three-stage concentrated DTRO device enters the concentrated brine collection pool. It is necessary to add antiscalant and hydrochloric acid to prevent scaling inside the MVR equipment and adjust the pH change. After entering the MVR evaporation device, the water in the wastewater is mainly evaporated into condensed water, and impurities are condensed into solids. The condensed water enters the condensation water tank and then enters the reuse water pool. In addition, the backwash water of the manganese sand filter, the flushing water of the self-cleaning filter, the backwash water of the UF system, and the sludge of the softening clarification tank enter the sludge pool for concentration, and finally enter the sludge dewatering machine for dehydration.

[0034] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A paper mill high-salinity reclaimed water recycling treatment device, characterized in that: include A reclaimed water collection tank, a manganese sand filter, a clear water tank, a self-cleaning filter, a UF system and a UF water production tank are sequentially connected by pipelines, and the outlet of the UF water production tank is connected to a primary RO concentration device through a pipeline, and the primary RO concentration device includes a primary security filter, a primary RO concentration membrane and a primary RO concentrated water tank that are sequentially connected by pipelines; A secondary RO concentrating device, the secondary RO concentrating device comprises a secondary RO concentrating membrane and a secondary RO concentrated water tank, the primary RO concentrated water tank is connected to the secondary RO concentrating membrane via a secondary security filter; The secondary RO concentrated water tank is sequentially connected by pipelines with a hardness removal reaction tank, a hardness removal coagulation tank, a hardness removal flocculation tank, a softening clarification tank, a tubular ultrafiltration membrane, a tubular ultrafiltration water production tank, a softener, a softened water tank, a three-stage security filter, a three-stage concentrated DTRO device, a concentrated brine collection tank, an MVR evaporation device and a condensation water tank.

2. A paper mill high-salinity reclaimed water recycling treatment device according to claim 1, characterized in that: It also includes a reuse water pool, and the water outlet of the first-level RO concentration membrane, the water outlet of the second-level RO concentration membrane, the water outlet of the third-level concentration DTRO device, the water outlet of the MVR evaporation device and the water outlet of the condensation water tank are all connected to the reuse water pool through pipelines.

3. A paper mill high-salinity reclaimed water recycling treatment device according to claim 1, characterized in that: It also includes a sludge pool, and the sewage outlet of the manganese sand filter, the sewage outlet of the self-cleaning filter, the sewage outlet of the UF system and the sewage outlet of the softening and clarifying tank are all connected to the sludge pool through pipelines.

4. A paper mill high-salinity reclaimed water recycling treatment device according to claim 3, characterized in that: A sludge dewatering machine is arranged at the end of the sludge pool to dewater the sludge.

5. The device for recycling high-salinity reclaimed water in a paper mill according to claim 1, characterized in that: The primary RO concentrating membrane and the secondary RO concentrating membrane are both anti-pollution membranes.

6. The device for recycling high-salinity reclaimed water in a paper mill according to claim 1, characterized in that: The UF system uses a UF backwash pump for backwashing, and 10% hydrochloric acid or 10% sodium hypochlorite is added during the backwashing process every 3-7 days.

7. The device for recycling high-salinity reclaimed water in a paper mill according to claim 1, characterized in that: The UF water production tank, the first-level RO concentrated water tank and the second-level RO concentrated water tank are all added with a reducing agent with an effective content of 5%-10%, a scale inhibitor with an effective content of 5%-15%, and a non-oxygen bactericide with an effective content of 100%. The non-oxygen bactericide is added intermittently and regularly.

8. The device for recycling high-salinity reclaimed water in a paper mill according to claim 1, characterized in that: The hardness removal reaction tank, the hardness removal coagulation tank, the hardness removal flocculation tank and the softening clarification tank are all reaction tanks made of carbon steel lining FRP material.

9. A paper mill high-salinity reclaimed water recycling treatment device according to claim 8, characterized in that: A 30% sodium carbonate solution and a 30% sodium hydroxide solution are added into the hardness removal reaction tank to adjust the pH of the wastewater to 10-11.5; A PAC solution with an effective Al2O3 content of 10% is added into the de-hardening coagulation tank; A 0.1% concentration of anionic PAM solution is added into the hardness removal flocculation tank.

10. The device for recycling high-salinity reclaimed water in a paper mill according to claim 1, characterized in that: The softener is a reactor with a carbon steel rubber lining and a 1200 mm thick softening resin filled therein. A 30% hydrochloric acid solution or a 30% sodium hydroxide solution is added into the softener to adjust the pH of the wastewater to 7.

Images