CN111875094A - Comprehensive treatment process for beryllium-containing wastewater - Google Patents

Abstract

The invention discloses a comprehensive treatment process for beryllium-containing wastewater. a. The wastewater is classified into recycled BeO washing wastewater, raffinate wastewater and mixed wastewater and collected in a collection tank respectively; b. the recycled BeO washing wastewater and raffinate wastewater are mixed The wastewater is separately treated as front-end wastewater; c. The BeO washing wastewater front-end clear liquid, raffinate wastewater front-end clear liquid, and mixed wastewater front-end clear liquid are classified and recycled, and the BeO washing wastewater front-end concentrate, raffinate wastewater front-end concentrate, and mixed wastewater are recycled The comprehensive wastewater formed after the concentrated liquid at the front end of the wastewater is merged is subjected to back-end comprehensive wastewater treatment. Based on the characteristics of beryllium smelting and beryllium product production wastewater, the present invention treats wastewater with high acid concentration separately, which can avoid a large amount of alkali consumption and solve the technical problem of a substantial increase in the cost of subsequent high-salt wastewater treatment in traditional water treatment processes; each process is combined High-concentration wastewater forms a comprehensive wastewater centralized treatment, and low-concentration freshwater after comprehensive wastewater treatment forms an internal circulation process, which reduces the process load and operating cost of the entire wastewater treatment system.

Description

Comprehensive treatment process of beryllium-containing wastewater

technical field

The invention relates to the technical field of non-ferrous metal production, in particular to a comprehensive treatment process for beryllium-containing wastewater.

Background technique

In industrial production, especially the comprehensive beryllium-containing wastewater produced by non-ferrous metal production and the production of smelting, mining, special materials, radio equipment and instrument parts, a large amount of beryllium-containing wastewater is often discharged, and even in non-ferrous metal production employees' clothes washing wastewater All contain beryllium element, as well as alkaline washing wastewater and oxalic acid washing wastewater in production. This part of the wastewater contains a large amount of acid, alkali and beryllium salts. Beryllium is a highly toxic substance, and the environmental protection discharge requirements are extremely strict. However, the concentration of beryllium in many beryllium-containing wastewater is very low, and the reuse value is not high. Therefore, the treatment technology is very difficult, resulting in a great discharge pressure.

For the treatment of beryllium-containing wastewater, traditional physical and chemical methods, such as chemical precipitation, ion exchange, adsorption, electrolysis, coagulation, redox and ferrite, all require the use of lime milk to precipitate wastewater. Most of the beryllium salts are removed, and then separated and removed by means of sedimentation separation and flocculation, and by means of physical filtration. Due to the huge volume of wastewater and the low concentration of beryllium salt, a large amount of lime milk is consumed, and even the sedimentation effect is improved by means of flocculants to stabilize the subsequent physical filtration operation process. The above traditional physical and chemical methods not only fail to achieve a good separation effect, but also have a lengthy process and high operating costs. At the same time, the traditional physical and chemical methods add a large amount of precipitants and flocculants, which increases new environmental pressures.

In recent years, biological methods have gradually become the main development direction in the field of non-ferrous metal production wastewater treatment. However, due to the high environmental requirements for bacterial activity, the fields of beryllium-containing sewage are quite extensive and the components are complex. Therefore, huge and harsh pre-treatment is required as a prerequisite for the final biological treatment of beryllium-containing wastewater, and it is difficult to adapt to various complex beryllium-containing wastewater systems discharged from different fields even if different strains of bacteria are used for biological treatment. . In addition, the biological method of bacteria has low mechanical strength, low density and fine particles, and it is difficult to separate solid and liquid after adsorbing metals. For beryllium-containing wastewater with complex working conditions or low content, the bacterial cells are easy to lose activity or difficult to achieve optimal biological activity conditions, which makes the entire beryllium-containing wastewater treatment process extremely unstable.

Therefore, there is an urgent need for a comprehensive treatment system and process for beryllium-containing wastewater.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a comprehensive treatment system for beryllium-containing wastewater, so as to solve the problem of poor comprehensive treatment effect of beryllium-containing wastewater in the prior art.

In order to achieve the above object, according to an aspect of the present invention, a comprehensive treatment system for beryllium-containing wastewater is provided, including a classification processing front end and a comprehensive processing back end;

The front-end of classification treatment, including the front-end of recycling BeO washing wastewater, the front-end of raffinate wastewater, and the front-end of mixed wastewater;

The front-end of the recycling BeO washing wastewater treatment includes a collection tank for recycling BeO washing wastewater, a preliminary filtering device for recycling BeO washing wastewater, a membrane clarification device for recycling BeO washing wastewater, and a membrane purification device for recycling BeO washing wastewater;

The front end of raffinate wastewater treatment includes a raffinate wastewater collection tank, a raffinate wastewater preliminary filtering device, a raffinate wastewater membrane clarification device, and a raffinate wastewater membrane purification device that are connected in sequence;

The front end of mixed wastewater treatment includes a mixed wastewater collection tank, a pH adjustment tank, a mixed wastewater preliminary filtration device, a mixed wastewater membrane clarification device, and a fine filtration membrane separation device connected in sequence;

The back-end of the comprehensive treatment includes: a back-end pH adjustment tank, a back-end pre-filtration device connected to the supernatant outlet of the back-end pH adjustment tank, a back-end membrane clarification device, and a membrane concentration system;

Wherein, the concentrated liquid outlet of the recovery BeO washing wastewater membrane purification device, the concentrated liquid outlet of the raffinate wastewater membrane purification device, and the concentrated liquid outlet of the fine filtration membrane separation device are all communicated with the back-end pH adjustment tank.

Further, the membrane clarification device for recycling BeO washing wastewater is a cross-flow filtration device, and the concentrate outlet of the membrane clarification device for recycling BeO washing wastewater is communicated with a collection tank for recycling BeO washing wastewater.

Further, the raffinate wastewater membrane clarification device is a cross-flow filtration device, and the concentrate outlet of the raffinate wastewater membrane clarification device is communicated with the raffinate wastewater collection tank.

Further, the mixed wastewater membrane clarification device is a cross-flow filtration device, and the concentrated liquid outlet of the mixed wastewater of the mixed wastewater membrane clarification device is connected to the pH adjustment tank at the back end.

Further, a plate and frame filter press is connected to the concentrated liquid outlet of the pH adjustment tank, and the filtrate outlet of the plate and frame filter press is connected to the mixed waste water collection tank.

Further, the dope outlet of the back-end pH adjustment tank is connected with a back-end plate and frame filter press, and the filtrate outlet of the back-end plate and frame filter press is communicated with the liquid inlet of the mixed wastewater membrane clarification device.

Further, the dope outlet of the back-end membrane clarification device is connected to the back-end pH adjustment tank.

Further, the preliminary filtering device for recovered BeO washing wastewater, the preliminary filtering device for raffinate wastewater, the preliminary filtering device for mixed wastewater, and the pre-filtering device at the back end all include a plate-and-frame filtering device or a bag filtering device.

Further, when the wastewater is low-concentration wastewater, the back-end membrane concentration system includes a membrane separation device that removes part of divalent inorganic salts, a concentration desalination device that intercepts most of the inorganic salts, and a refinement device that further intercepts inorganic salts. Desalination device; when the wastewater is high-concentration wastewater, the back-end membrane concentration system includes a membrane separation device, a fine filtration device and an electrodialysis device.

Further, the recovered BeO washing wastewater membrane clarification device, the raffinate wastewater membrane clarification device, the mixed wastewater membrane clarification device, and the back-end membrane clarification device are all inorganic membrane filtration devices, organic membrane filtration devices, roll-type membrane filtration devices, and discs. One of the membrane filtration device, plate membrane filtration device, hollow fiber membrane filtration device and tubular membrane filtration device, its molecular weight cut off is 5000Da, 8000Da, 10000Da, 30000Da, 50000Da, 80000Da, 100000Da, 150000Da, 200000Da, 250000Da a kind of;

The purification membranes used in the membrane purification of BeO washing wastewater are inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, disc membrane filtration devices, plate membrane filtration devices, hollow fiber membrane filtration devices, and tubular membrane filtration devices. A kind of, its molecular weight cut off is 5000Da;

The purification membranes used in membrane purification of raffinate wastewater are inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, disc membrane filtration devices, plate membrane filtration devices, hollow fiber membrane filtration devices, and tubular membrane filtration devices. A kind of molecular weight cut-off of 5000Da, 3000Da, 2500Da, 1000Da, 800Da, 500Da, 300Da, 150Da, 100Da, 50Da, 40Da, 30Da, 20Da;

The mixed wastewater is separated by filtration membrane using one of inorganic membrane filtration device, organic membrane filtration device, roll membrane filtration device, disc membrane filtration device, plate membrane filtration device, hollow fiber membrane filtration device and tubular membrane filtration device.

In order to achieve the above object, according to another aspect of the present invention, a comprehensive treatment process for beryllium-containing wastewater is also provided, comprising the following steps:

a. The waste water is classified into recycled BeO washing waste water, raffinate waste water and mixed waste water and collected in the collection tank respectively, wherein the mixed waste water includes domestic and bath waste water, lean organic alkali washing waste water, and lean organic acid washing waste water;

b. The recycled BeO washing wastewater is subjected to preliminary filtration, membrane clarification, and membrane purification in sequence to obtain the front-end clear liquid of the recycled BeO washing wastewater and the front-end concentrated liquid of the recycled BeO washing wastewater; the raffinate wastewater is sequentially subjected to preliminary filtration, membrane clarification, and membrane purification to obtain extract The front-end clear liquid of the residual wastewater and the front-end concentrated liquid of the raffinate wastewater; the mixed wastewater is sequentially subjected to pH adjustment, preliminary filtration, membrane clarification, and fine filtration membrane separation to obtain the front-end clear liquid of the mixed wastewater and the front-end concentrated liquid of the mixed wastewater;

c. The front-end clear liquid of the recovered BeO washing wastewater, the front-end clear liquid of the raffinate wastewater, and the front-end clear liquid of the mixed wastewater are classified and recycled, and the front-end concentrate of the recycled BeO washing wastewater, the front-end concentrate of the raffinate wastewater, and the front-end concentrate of the mixed wastewater are combined to form The comprehensive wastewater is adjusted by pH, and the clear liquid obtained by pH adjustment is successively subjected to back-end pre-filtration, back-end membrane clarification, and back-end membrane concentration to obtain recyclable fresh water and concentrated water discharged from the system.

Further, after the recovered BeO washing wastewater in step b is clarified by the membrane, the obtained concentrate is returned to the collection tank of the BeO washing wastewater.

Further, after the raffinate wastewater in step b is clarified by the membrane, the obtained concentrate is returned to the collection tank of the raffinate wastewater.

Further, the concentrated solution obtained by the membrane clarification of the mixed wastewater in step b is also combined with the front-end concentrated solution of the recovered BeO washing wastewater, the front-end concentrated solution of the raffinate wastewater, and the front-end concentrated solution of the mixed wastewater and adjusted for pH.

Further, after pH adjustment of the mixed waste water in step b, the obtained concentrated solution is subjected to pressure filtration, and the filtrate obtained by pressure filtration is returned to the mixed waste water collection tank.

Further, in step c, the concentrated solution of the front end of the BeO washing wastewater, the front end concentrated solution of the raffinate waste water, and the front end concentrated solution of the mixed waste water are collected, and the concentrated solution obtained after pH adjustment is subjected to pressure filtration. After the liquid is confluent, it enters the rear-end membrane clarification section.

Further, the dope obtained from the back-end membrane clarification is returned to the back-end pH adjustment section to repeat step c.

Further, the preliminary filtration of the recycled BeO washing wastewater, the preliminary filtration of the raffinate wastewater, the preliminary filtration of the mixed wastewater, and the back-end pre-filtration are all plate and frame filtration or bag filtration.

Further, the back-end membrane concentration includes membrane separation to remove part of divalent inorganic salts, concentrated desalination to intercept most of the inorganic salts, and refined desalination to further intercept inorganic salts.

Further, when the waste water is low-concentration waste water, the back-end membrane concentration includes membrane separation, concentration desalination and fine desalination; when the waste water is high-concentration waste water, the back-end membrane concentration includes membrane separation, fine Filtration and Electrodialysis.

Further, the recovered BeO washing wastewater membrane clarification device, the raffinate wastewater membrane clarification device, the mixed wastewater membrane clarification device, and the back-end membrane clarification device are all inorganic membrane filtration devices, organic membrane filtration devices, roll-type membrane filtration devices, and discs. One of the membrane filtration device, plate membrane filtration device, hollow fiber membrane filtration device and tubular membrane filtration device, its molecular weight cut off is 5000Da, 8000Da, 10000Da, 30000Da, 50000Da, 80000Da, 100000Da, 150000Da, 200000Da, 250000Da a kind of;

The purification membranes used in the membrane purification of BeO washing wastewater are inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, disc membrane filtration devices, plate membrane filtration devices, hollow fiber membrane filtration devices, and tubular membrane filtration devices. A kind of, its molecular weight cut off is 5000Da;

The purification membranes used in membrane purification of raffinate wastewater are inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, disc membrane filtration devices, plate membrane filtration devices, hollow fiber membrane filtration devices, and tubular membrane filtration devices. A kind of molecular weight cut-off of 5000Da, 3000Da, 2500Da, 1000Da, 800Da, 500Da, 300Da, 150Da, 100Da, 50Da, 40Da, 30Da, 20Da;

The mixed wastewater is separated by filtration membrane using one of inorganic membrane filtration device, organic membrane filtration device, roll membrane filtration device, disc membrane filtration device, plate membrane filtration device, hollow fiber membrane filtration device and tubular membrane filtration device.

It can be seen that, according to the characteristics of beryllium smelting and beryllium product production sewage, the present invention treats the wastewater with high acid concentration separately, which can avoid a large amount of alkali consumption and solve the technical problem that the cost of subsequent high-salt wastewater treatment in the traditional water treatment process is greatly increased;

The high-concentration wastewater of each process is formed into a comprehensive wastewater for centralized treatment, and the low-concentration fresh water after the comprehensive wastewater treatment is formed into an internal circulation treatment, which reduces the process load and operating cost of the entire wastewater treatment system. The whole technical scheme is economical, and the process route design is scientific and reasonable.

The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The accompanying drawings that constitute a part of the present invention are used to assist the understanding of the present invention, and the content provided in the drawings and their related descriptions in the present invention can be used to explain the present invention, but do not constitute an improper limitation of the present invention. In the attached image:

1 is a schematic diagram of the process flow of the comprehensive treatment equipment for beryllium-containing wastewater according to the present invention.

FIG. 2 is one of the structural schematic diagrams of the back-end membrane concentration system in the present invention.

FIG. 3 is the second structural schematic diagram of the back-end membrane concentration system in the present invention.

Detailed ways

The present invention will be clearly and completely described below with reference to the accompanying drawings. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Before the present invention is described in conjunction with the accompanying drawings, it should be particularly pointed out that:

The technical solutions and technical features provided in the various parts including the following description in the present invention can be combined with each other under the condition of no conflict.

In addition, the embodiments of the present invention referred to in the following description are generally only a part of the embodiments of the present invention, not all of the embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Regarding the terms and units in the present invention. The terms "comprising", "having" and any variations thereof in the description and claims of the present invention and related parts are intended to cover non-exclusive inclusions. As shown in Figure 1:

A comprehensive treatment system for beryllium-containing wastewater, including the front-end of classified treatment and the back-end of comprehensive treatment;

The front-end of classification treatment, including the front-end of recycling BeO washing wastewater, the front-end of raffinate wastewater, and the front-end of mixed wastewater;

The front-end for recycling BeO washing wastewater treatment includes a collection tank 11 for recycling BeO washing wastewater, a preliminary filtering device 12 for recycling BeO washing wastewater, a membrane clarification device 13 for recycling BeO washing wastewater, and a membrane purification device 14 for recycling BeO washing wastewater;

The front end of raffinate wastewater treatment includes a raffinate wastewater collection tank 21, a raffinate wastewater preliminary filtering device 22, a raffinate wastewater membrane clarification device 23, and a raffinate wastewater membrane purification device 24, which are connected in sequence;

The front end of mixed wastewater treatment includes a mixed wastewater collection tank 31, a pH adjustment tank 32, a preliminary mixed wastewater filtering device 33, a mixed wastewater membrane clarification device 34, and a fine filtration membrane separation device 35, which are connected in sequence;

The back-end of the comprehensive treatment includes: a back-end pH adjusting tank 41, a back-end pre-filtration device 42 connected to the supernatant outlet of the back-end pH adjusting tank 41, a back-end membrane clarification device 43, and a membrane concentration system 44;

Wherein, the concentrated liquid outlet of the recovery BeO washing wastewater membrane purification device 14 , the concentrated liquid outlet of the raffinate wastewater membrane purification device 24 , and the concentrated liquid outlet of the fine filtration membrane separation device 35 are all connected with the back-end pH adjustment tank 41 .

The membrane clarification device 13 for recycling BeO washing waste water is a cross-flow filtration device, and the concentrate outlet of the membrane clarification device 13 for recycling BeO washing waste water is communicated with the collection tank 11 for recycling BeO washing waste water.

The raffinate wastewater membrane clarification device 23 is a cross-flow filtration device, and the concentrate outlet of the raffinate wastewater membrane clarification device 23 is communicated with the raffinate wastewater collection tank 21 .

The mixed wastewater membrane clarification device 34 is a cross-flow filtration device, and the concentrate outlet of the mixed wastewater membrane clarification device 34 is connected to the pH adjustment tank 41 at the back end.

A plate and frame filter press 36 is connected to the concentrated liquid outlet of the pH adjustment tank 32 , and the filtrate outlet of the plate and frame filter press 36 is connected to the mixed waste water collection tank 31 .

The dope outlet of the rear pH adjustment tank 41 is connected with a rear plate and frame filter press 45 , and the filtrate outlet of the rear plate and frame filter press 45 is connected with the liquid inlet of the mixed wastewater membrane clarification device 34 .

The dope outlet of the back-end membrane clarification device 43 is connected to the back-end pH adjustment tank 41 .

The preliminary filtering device 12 for recovered BeO washing wastewater, the preliminary filtering device 22 for raffinate wastewater, the preliminary filtering device 33 for mixed wastewater, and the pre-filtering device 42 at the rear end all include a plate-and-frame filtering device or a bag filtering device.

As shown in FIG. 2 and FIG. 3 , when the wastewater is low-concentration wastewater, the back-end membrane concentration includes membrane separation, concentrated desalination and fine desalination; when the wastewater is high-concentration wastewater, the back-end membrane concentration Concentration includes membrane separation, fine filtration, and electrodialysis.

The recovered BeO washing wastewater membrane clarification device, raffinate wastewater membrane clarification device, mixed wastewater membrane clarification device, and back-end membrane clarification device are all inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, and disc membrane filtration devices. One of the device, plate membrane filtration device, hollow fiber membrane filtration device and tubular membrane filtration device, and its molecular weight cut off is one of 5000Da, 8000Da, 10000Da, 30000Da, 50000Da, 80000Da, 100000Da, 150000Da, 200000Da, 250000Da ;

The purification membranes used in the membrane purification of BeO washing wastewater are inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, disc membrane filtration devices, plate membrane filtration devices, hollow fiber membrane filtration devices, and tubular membrane filtration devices. A kind of, its molecular weight cut off is 5000Da;

The purification membranes used in membrane purification of raffinate wastewater are inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, disc membrane filtration devices, plate membrane filtration devices, hollow fiber membrane filtration devices, and tubular membrane filtration devices. A kind of molecular weight cut-off of 5000Da, 3000Da, 2500Da, 1000Da, 800Da, 500Da, 300Da, 150Da, 100Da, 50Da, 40Da, 30Da, 20Da;

The mixed wastewater is separated by filtration membrane using one of inorganic membrane filtration device, organic membrane filtration device, roll membrane filtration device, disc membrane filtration device, plate membrane filtration device, hollow fiber membrane filtration device and tubular membrane filtration device.

The comprehensive treatment process of beryllium-containing wastewater includes the following steps:

a. The waste water is classified into recycled BeO washing waste water, raffinate waste water and mixed waste water and collected in the collection tank respectively, wherein the mixed waste water includes domestic and bath waste water, lean organic alkali washing waste water, and lean organic acid washing waste water;

b. The recycled BeO washing wastewater is subjected to preliminary filtration, membrane clarification, and membrane purification in sequence to obtain the front-end clear liquid of the recycled BeO washing wastewater and the front-end concentrated liquid of the recycled BeO washing wastewater; the raffinate wastewater is sequentially subjected to preliminary filtration, membrane clarification, and membrane purification to obtain extract The front-end clear liquid of the residual wastewater and the front-end concentrated liquid of the raffinate wastewater; the mixed wastewater is sequentially subjected to pH adjustment, preliminary filtration, membrane clarification, and fine filtration membrane separation to obtain the front-end clear liquid of the mixed wastewater and the front-end concentrated liquid of the mixed wastewater;

c. The front-end clear liquid of the recovered BeO washing wastewater, the front-end clear liquid of the raffinate wastewater, and the front-end clear liquid of the mixed wastewater are classified and recycled, and the front-end concentrate of the recycled BeO washing wastewater, the front-end concentrate of the raffinate wastewater, and the front-end concentrate of the mixed wastewater are combined to form The comprehensive wastewater is adjusted by pH, and the clear liquid obtained by pH adjustment is successively subjected to back-end pre-filtration, back-end membrane clarification, and back-end membrane concentration to obtain recyclable fresh water and concentrated water discharged from the system.

After the recovered BeO washing wastewater in step b is clarified by the membrane, the obtained concentrate is returned to the collection tank of the BeO washing wastewater.

After the raffinate wastewater in step b is clarified by the membrane, the obtained concentrate is returned to the collection tank of the raffinate wastewater.

The concentrated solution obtained by the membrane clarification of the mixed wastewater in step b is also combined with the front-end concentrated solution of the recovered BeO washing wastewater, the front-end concentrated solution of the raffinate wastewater, and the front-end concentrated solution of the mixed wastewater and adjusted for pH.

After the mixed waste water in step b is adjusted by pH, the obtained concentrated solution is subjected to pressure filtration, and the filtrate obtained by pressure filtration is returned to the mixed waste water collection tank.

In step c, the front-end concentrated solution of the BeO washing wastewater, the front-end concentrated solution of the raffinate waste water, and the front-end concentrated solution of the mixed waste water are recovered, and then the concentrated solution obtained after pH adjustment is subjected to pressure filtration. Enter the back-end membrane clarification section.

The dope obtained from the clarification of the back-end membrane is returned to the back-end pH adjustment section to repeat step c.

The preliminary filtration of the recovered BeO washing wastewater, the preliminary filtration of the raffinate wastewater, the preliminary filtration of the mixed wastewater, and the back-end pre-filtration are all plate and frame filtration or bag filtration.

The back-end membrane concentration includes membrane separation to remove part of divalent inorganic salts, concentrated desalination to intercept most of the inorganic salts, and refined desalination to further intercept inorganic salts.

The recovered BeO washing wastewater membrane clarification device, raffinate wastewater membrane clarification device, mixed wastewater membrane clarification device, and back-end membrane clarification device are all inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, and disc membrane filtration devices. One of the device, plate membrane filtration device, hollow fiber membrane filtration device and tubular membrane filtration device, and its molecular weight cut off is one of 5000Da, 8000Da, 10000Da, 30000Da, 50000Da, 80000Da, 100000Da, 150000Da, 200000Da, 250000Da .

The following is a detailed description of each process section and the equipment used:

Preliminary filter section

The purpose of the preliminary filtration is to intercept the large particles and most of the hard and fine particles in the sewage, so as to avoid damage to the impeller and clarification membrane under the high-speed operation of the circulating pump; the filtration of the preliminary filtration section is carried out according to the solid content of different wastewater and whether the pH needs to be adjusted. method to select.

For wastewater containing a small amount of suspended solids, the wastewater with a small amount of suspended solids is directly pretreated by bag filtration or multi-media filtration;

For sewage or slurry materials with a solid content of more than 2%, such as the above mixed wastewater, it can be considered to directly use a plate and frame filter press, a sludge centrifuge or other separation equipment for preliminary filtration treatment;

For fine particles that are difficult to filter and whose content is less than 1% or are difficult to be divided into fine particles that need to be adjusted in advance to adjust the pH value of sewage, the pre-settled concentrate can be filtered by plate and frame or other solid-liquid separation equipment to improve the solid-liquid separation efficiency. ; And the clear liquid after sedimentation can be considered for preliminary filtration treatment by means of plate and frame or bag filtration;

The mesh number of the plate and frame filtration is 500-2500 mesh; the filtration precision of the bag filtration is 1-10 μm.

The mesh number of the plate and frame filter press is 500-2500 mesh.

Membrane clarification section

The main purpose of membrane clarification is to use the characteristics of "cross-flow filtration" of membrane separation to solve the technical problem that traditional "dead-end" filtration is easy to block, and at the same time, to provide qualified influent water for subsequent fine filtration.

The membrane clarification device is selected according to the different materials entering the system: for the materials with strong corrosion resistance, PP, PVDF and inorganic materials with strong corrosion resistance can be used; for the solid content from low to high, the internal pressure hollow can be used Fiber membranes, external pressure hollow fiber membranes, and tubular structure membranes are used to overcome the technical difficulties of traditional "dead end" filtration.

Membrane purification

The purification membranes used in the membrane purification of BeO washing wastewater are inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, disc membrane filtration devices, plate membrane filtration devices, hollow fiber membrane filtration devices, and tubular membrane filtration devices. A kind of, its molecular weight cut off is 5000Da;

The purification membranes used in membrane purification of raffinate wastewater are inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, disc membrane filtration devices, plate membrane filtration devices, hollow fiber membrane filtration devices, and tubular membrane filtration devices. A kind of molecular weight cut-off of 5000Da, 3000Da, 2500Da, 1000Da, 800Da, 500Da, 300Da, 150Da, 100Da, 50Da, 40Da, 30Da, 20Da;

The mixed wastewater is separated by filtration membrane using one of inorganic membrane filtration device, organic membrane filtration device, roll membrane filtration device, disc membrane filtration device, plate membrane filtration device, hollow fiber membrane filtration device and tubular membrane filtration device.

Fine filtration membrane separation

The purpose of fine filtration membrane separation is to make the supernatant meet the requirements of recycling production or treatment to meet the discharge requirements.

According to the different materials entering the system: for highly corrosive materials, a corrosion-resistant material film can be used; while common materials can use a general-purpose material film to meet the requirements.

According to the processing requirements of different precisions: the structure of the supernatant outlet of the first-stage membrane purification device can be used in series with multi-stage membrane purification, so that the supernatant separated by the fine filtration membrane can meet the requirements of reuse or discharge; According to the requirements of the index, the structure of multi-stage membrane purification is connected in series at the concentrate outlet of the primary membrane purification device to improve the concentration of the concentrated solution of the system and meet the requirements of the subsequent process inlet; two primary membrane purification devices can also be used in parallel.

The clear liquid obtained by the fine filtration membrane separation device is directly discharged or reused and produced, and the concentrated liquid whose volume is greatly reduced after the concentrated liquid enters the next process, thereby improving the processing efficiency of the next process.

Membrane concentration system

The purpose of the membrane concentration system is to achieve the best economic benefits for the reuse and production or subsequent treatment of the concentrate, regardless of the concentration of the clear liquid or fresh water.

The membrane separation device in the membrane concentration system adopts a nanofiltration device, and the nanofiltration device is one of a roll type, a butterfly type or a plate type membrane nanofiltration device.

The concentration and desalination device in the membrane concentration system adopts a reverse osmosis device, and the molecular weight cut-off of the concentration and desalination device is one of 300Da, 150Da, 100Da, 50Da, 30Da, 10Da.

The fine desalination device in the membrane concentration system adopts a reverse osmosis device, and the filtration precision of the fine desalination device is one of 300Da, 150Da, 100Da, 50Da, 30Da, and 10Da.

The fine filtration used adopts one of inorganic membrane filtration device, organic membrane filtration device, roll membrane filtration device, disc membrane filtration device, plate membrane filtration device, hollow fiber membrane filtration device and tubular membrane filtration device. It is one of 5000Da, 3000Da, 2500Da, 1000Da, 800Da, 500Da, 300Da, 150Da, 100Da, 50Da, 40Da, 30Da, 20Da, 10Da. The electrodialysis used is inorganic ion exchange membrane electrodialysis, organic polymer ion exchange membrane electrodialysis, homogeneous ion exchange membrane electrodialysis, semi-homogeneous ion exchange membrane electrodialysis, heterogeneous ion exchange membrane electrodialysis, coagulation. colloidal ion exchange membrane electrodialysis, porous ion exchange membrane electrodialysis, macroporous ion exchange membrane electrodialysis, cation exchange membrane electrodialysis, anion exchange membrane electrodialysis, special functional ion exchange membrane electrodialysis, general water treatment ion Exchange membrane electrodialysis, ion exchange membrane electrodialysis for special purposes, no mesh membrane electrodialysis, mesh membrane electrodialysis, substrate membrane electrodialysis, different combinations of the same principle as electrodialysis and dialysis under the action of an electric field have the function of desalination one of various devices.

Example

In the smelting, production or purification process of beryllium, beryllium oxide or beryllium salt, a lot of strong acid waste water, strong alkali waste water and other waste water are often produced. There are many types of beryllium-containing wastewater, including recycling BeO washing wastewater, raffinate wastewater, and mixed wastewater composed of pickling wastewater, alkali washing wastewater, and bathing and domestic wastewater. The above-mentioned comprehensive wastewater generated by the recovery of beryllium and beryllium oxides is taken as an example to specifically introduce the technical solution of the present invention.

The components of mixed wastewater composed of recycled BeO washing wastewater, raffinate wastewater, acid washing wastewater, alkali washing wastewater and bathing and domestic wastewater are shown in the following table:

According to the above feeding situation of beryllium-containing wastewater, the analysis is as follows:

1) Recycling BeO washing waste liquid: Since the waste water contains relatively high-value oxalic acid, it has great recycling value. The treatment method of recycling BeO washing wastewater is the same as that of raffinate wastewater. The special membrane of patented acid-resistant material is used for treatment, which not only saves a lot of neutralization alkali, but also recovers oxalic acid with high value, so as to achieve the purpose of energy saving and consumption reduction.

2) Raffinate water phase: The raffinate wastewater is extremely acidic, and although the recovery of sulfuric acid is not very valuable, it requires a lot of alkali to neutralize the sulfuric acid in the treatment of this type of wastewater. The raffinate wastewater after neutralization contains a large amount of salt, therefore, the methods for treating the raffinate wastewater are extremely limited, and the treatment cost is very high.

When treating this kind of wastewater, special membranes using patented acid-resistant materials are very suitable for treating raffinate wastewater. Not only does it not require a large amount of alkali to neutralize sulfuric acid, but the purified sulfuric acid after membrane purification can be reused and produced, forming a circular economy and truly achieving "zero emissions" in production.

3) Lean organic pickling wastewater: The sulfuric acid content of the lean organic pickling wastewater is relatively low and the volume is large. If the special membrane of patented acid-resistant material is used for treatment, the economy is not very prominent. Therefore, it is proposed to adopt the method of neutralization after pretreatment, and then use the economical ordinary membrane to treat this kind of wastewater.

4) Lean organic alkaline washing wastewater: Lean organic alkaline washing wastewater has the same properties as lean organic acid washing wastewater, and both are suitable for neutralization after pretreatment, and are treated with economical ordinary membranes.

5) Bathing and sanitary wastewater: Bathing and domestic wastewater mainly contains beryllium and cannot be discharged outside. It is suitable for beryllium interception directly by ordinary membrane after pretreatment.

The following three categories are classified:

1) Raffinate water phase: After pretreatment, special membrane with patented acid-resistant material is used to intercept impurities in wastewater, so that sulfuric acid can be purified and reused for production. The concentrated solution that intercepts impurities such as beryllium salt is transported to the concentrated solution treatment process for centralized treatment. The treated clear liquid is returned to the mixed wastewater for centralized treatment.

2) Recycling BeO washing waste liquid: After pretreatment, special membrane with patented acid-resistant material is used to intercept impurities in wastewater, so that oxalic acid can be purified and reused for production. The concentrated solution that intercepts impurities such as beryllium salt is transported to the concentrated solution treatment process for centralized treatment. The treated clear liquid is returned to the mixed wastewater for centralized treatment.

3) The mixed waste water after the treatment of lean organic acid washing waste water, lean organic alkali washing waste water, bathing and sanitation waste water and the internal sewage (including concentrated liquid) of the whole system are mixed for comprehensive treatment.

Using the above scheme to classify and treat wastewater has the following advantages:

1) The high-concentration acidic wastewater is purified by membrane separation and reused for production. Compared with the traditional treatment method of pre-acid-base neutralization, a large amount of neutralization alkali is saved, and the consumption of acid in production is reduced at the same time. The treatment method of the present invention has huge economic advantages;

2) The volume of beryllium-containing wastewater in production is greatly reduced after membrane concentration, which greatly improves the chemical reaction effect in the sewage treatment process, reduces the input of additives, reduces the environmental protection treatment pressure, and is quite environmentally friendly;

3) Using membrane technology for beryllium-containing wastewater treatment, the separation efficiency is high, and there is no need for lengthy and cumbersome processes.

4) According to the raw water conditions and treatment requirements of different working conditions, the present invention adopts the combination of membrane separation technology and electrodialysis, which can increase the inorganic salt content in the raw water to more than 20%. The useful substances in the wastewater or the environmental protection treatment are not beneficial, and the "circular economy" is completely realized and "zero discharge" is achieved.

Recycling BeO washing waste liquid:

The recovered BeO washing waste liquid is collected from each process point to the waste water collection tank for mixing, and then the large particles and hard particles are initially filtered out by the plate frame or cloth bag, and then enter the membrane clarification device, and the slag or material will be collected and shipped. The membrane clarification device adopts cross-flow circulating filtration, which intercepts fine particles and a part of macromolecular impurities that cannot be filtered by the plate frame or cloth bag to form a concentrated liquid that is returned to the collection tank of the recovered BeO washing waste liquid; the clear liquid passes through the membrane to form a pure permeable liquid. The liquid is transported to a nanofiltration device with higher filtration accuracy for desalination and purification; the nanofiltration device uses the molecular weight and charge in the solution to intercept most of the inorganic salts through membrane purification, and the concentrated solution formed by membrane purification enters the next back end. Comprehensive treatment is carried out in the comprehensive wastewater treatment stage. The pure clear liquid through the nanofiltration membrane, that is, the oxalic acid solution, needs to enter the recovery process for fine desalination due to its high purity requirements. The oxalic acid solution after fine desalination is returned to production after acid supplementation and qualified testing. use.

Raffinate water phase: The recovered raffinate water phase wastewater is collected from each process point to the raffinate water phase wastewater collection tank for mixing, and then the large particles and hard particles are initially filtered out by the plate frame or cloth bag, and then enter the membrane clarification device, and the slag or material will be Collect shipments. The membrane clarification device adopts cross-flow circulating filtration, which intercepts the fine particles that cannot be filtered by the plate frame or the cloth bag and a part of the macromolecular impurities to form a concentrated solution and returns to the collection tank; The nanofiltration system with higher filtration precision is used for desalination and purification; the membrane purification system uses the molecular weight and charge in the solution to intercept most of the inorganic salts, and forms a concentrated solution that enters the next back-end comprehensive wastewater treatment stage for comprehensive treatment. Membrane pure sulfuric acid is returned to production after acid supplementation and qualified testing.

Mixed wastewater pretreatment: pickling wastewater, bathing and sanitary wastewater and pickling wastewater are collectively referred to as mixed wastewater. The mixed wastewater is collected from each process point to the wastewater collection tank for mixing, and then the raw water pump and the metering dosing pump are mixed and reacted in the pipeline mixer according to a certain proportion until the pH is neutral, and the solution is precipitated due to the pH change. Sedimentation stratification occurs in the pH adjustment tank: the clear liquid in the stratification overflows to the clear liquid tank and is sent to the plate frame or bag filter device through the clear liquid pump, and the clear liquid obtained from the plate frame or bag filter device enters the membrane clarification device. The solid matter is transported out for treatment; the sediment in the tank is enriched in the lower part of the pH adjustment tank and sent to the plate and frame filter press through the slurry pump, the solid obtained by the plate and frame filter press is transported out, and the obtained filtrate is returned to the raw water collection tank.

After pretreatment, the mixed wastewater meets the feeding requirements of membrane clarification and enters the membrane clarification device. The membrane clarification device uses high-precision filtration in the pretreatment to retain fine particles and a part of macromolecular impurities that pass through the plate frame or bag filter to form a concentrated solution and enter the pH adjustment tank. ; The part that passes through the membrane clarification device is the clear liquid entering the fine filtration membrane separation system. The fine filtration membrane separation system adopts different processes and equipment structures to meet the different treatment requirements of mixed wastewater. The clear liquid passing through the membrane is directly reused for production or discharge up to the standard; the concentrated liquid enters the back-end pH adjustment tank of the comprehensive wastewater treatment stage for further treatment.

The recovery of BeO washing waste liquid concentrate, raffinate aqueous phase concentrate, mixed wastewater membrane clarification concentrate, mixed wastewater fine filtration membrane separation concentrate and integrated wastewater membrane clarification concentrate are collectively referred to as comprehensive wastewater. The comprehensive wastewater is collected from each process point to the back-end pH adjustment tank for mixing. Fresh raw water continuously enters the back-end pH adjustment tank, causing the pH value in the back-end pH adjustment tank to change. The dosing system adjusts the dosing amount according to the pH value signal feedback of the adjustment tank. , in order to meet the process requirements. Due to the change of pH, the solution precipitates to form a suspension, and sedimentation and stratification occur in the pH adjustment tank: the clear liquid partially overflows to the clear liquid tank and is sent to the clear liquid plate and frame filter press by the clear liquid pump, and the filtrate enters the membrane clarification device. The material is transported out of the tank; the sediment in the pH adjustment tank is enriched in the lower part of the pH adjustment tank and sent to the concentrated liquid plate and frame filter press through the mud pump, the solid is transported out, and the filtrate is returned to the pH adjustment tank.

After the clear liquid from the clear liquid plate and frame filter press enters the membrane clarification device, the clear liquid obtained after the membrane clarification device removes fine suspended solids and macromolecular substances enters the membrane separation device 441, and the concentrated liquid obtained from the membrane clarification returns to the pH adjustment tank. Continue to settling to separate the suspended solids.

The clear liquid obtained from the membrane separation of the low-concentration raw liquid first passes through the concentration desalination device 442, and the clear liquid obtained from the concentrated desalination device 442 enters the fine desalination device 443 for further desalination to obtain clear liquid, and the concentrated liquid obtained by the fine desalination device 443 is returned to the concentrated desalination device. device 442;

The clear liquid obtained from the membrane separation of the high-concentration stock solution is first filtered by the fine filtration device 446 , the concentrated liquid filtered by the fine filtration device 446 continues to enter the electrodialysis device 447 for concentration, and the concentrated liquid filtered by the electrodialysis device 447 is returned to the fine filtration device 446 .

Next, the beneficial effects of the present invention will be further described by comparing the experimental data of various wastewater treatment and comprehensive treatment in the technical scheme of the present invention respectively in the prior art:

The experimental data is shown in Table 2:

data analysis

According to the characteristics of sewage from beryllium smelting and production of beryllium products, separate treatment of wastewater with high acid concentration can avoid a large amount of alkali consumption and solve the technical problem that the cost of subsequent high-salt wastewater treatment in traditional water treatment processes is greatly increased;

The high-concentration wastewater of each process is formed into a comprehensive wastewater for centralized treatment, and the low-concentration fresh water after the comprehensive wastewater treatment is formed into an internal circulation treatment, which reduces the process load and operating cost of the entire wastewater treatment system. The whole technical scheme is economical, and the process route design is scientific and reasonable.

The content of the present invention has been described above. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Based on the above content of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Claims (10)

1. beryllium-containing wastewater comprehensive treatment process, is characterized in that, comprises the following steps: a. The waste water is classified into recycled BeO washing waste water, raffinate waste water and mixed waste water and collected in the collection tank respectively, wherein the mixed waste water includes domestic and bath waste water, lean organic alkali washing waste water, and lean organic acid washing waste water; b. The recycled BeO washing wastewater is subjected to preliminary filtration, membrane clarification, and membrane purification in sequence to obtain the front-end clear liquid of the recycled BeO washing wastewater and the front-end concentrated liquid of the recycled BeO washing wastewater; the raffinate wastewater is sequentially subjected to preliminary filtration, membrane clarification, and membrane purification to obtain extract The front-end clear liquid of the residual wastewater and the front-end concentrated liquid of the raffinate wastewater; the mixed wastewater is sequentially subjected to pH adjustment, preliminary filtration, membrane clarification, and fine filtration membrane separation to obtain the front-end clear liquid of the mixed wastewater and the front-end concentrated liquid of the mixed wastewater; c. The front-end clear liquid of the recovered BeO washing wastewater, the front-end clear liquid of the raffinate wastewater, and the front-end clear liquid of the mixed wastewater are classified and recycled, and the front-end concentrate of the recycled BeO washing wastewater, the front-end concentrate of the raffinate wastewater, and the front-end concentrate of the mixed wastewater are combined to form The comprehensive wastewater is adjusted by pH, and the clear liquid obtained by pH adjustment is successively subjected to back-end pre-filtration, back-end membrane clarification, and back-end membrane concentration to obtain recyclable fresh water and concentrated water discharged from the system. 2. The comprehensive treatment process for beryllium-containing wastewater as claimed in claim 1, characterized in that, the recovered BeO washing wastewater in step b is returned to the collection tank of the BeO washing wastewater after membrane clarification. 3. The comprehensive treatment process for beryllium-containing wastewater as claimed in claim 1, characterized in that, after the raffinate wastewater in step b is clarified by the membrane, the obtained concentrated solution is returned to the collection tank of the raffinate wastewater. 4. beryllium-containing wastewater comprehensive treatment process as claimed in claim 1, it is characterised in that the mixed waste water in step b is through membrane clarification gained thick liquor equally with reclaiming BeO washing wastewater front concentrated liquor, raffinate wastewater front concentrated liquor, mixing The wastewater front-end concentrate is pooled and pH adjusted. 5. The comprehensive treatment process for beryllium-containing waste water as claimed in claim 1, wherein the mixed waste water in step b is subjected to pressure filtration after pH adjustment, and the obtained concentrated solution is subjected to pressure filtration, and the filtrate obtained by pressure filtration is returned to the mixed waste water collection tank. 6. beryllium-containing wastewater comprehensive treatment process as claimed in claim 1, is characterized in that, in step c, reclaim BeO washing wastewater front-end dope, raffinate waste water front-end dope, mixed waste water front-end dope confluence and gained after pH adjustment The concentrated liquid is subjected to pressure filtration, and the filtrate obtained from the pressure filtration and the clear liquid obtained from the back-end pretreatment are combined and then enter the back-end membrane clarification section. 7 . The comprehensive treatment process for beryllium-containing wastewater according to claim 1 , wherein the back-end membrane clarification obtained dope is returned to the back-end pH adjustment section to repeat step c. 8 . 8. beryllium-containing wastewater comprehensive treatment process as claimed in claim 1 is characterized in that, described recycling BeO washing wastewater preliminary filtration, raffinate wastewater preliminary filtration, mixed waste water preliminary filtration, back-end pre-filtration are all plate and frame filtration or Bag filter. 9. The comprehensive treatment process for beryllium-containing wastewater according to claim 1, wherein when the wastewater is low-concentration wastewater, the back-end membrane concentration includes membrane separation, concentrated desalination and fine desalination; In the case of high-concentration wastewater, the back-end membrane concentration includes membrane separation, fine filtration and electrodialysis. 10. The comprehensive treatment process for beryllium-containing wastewater as claimed in claim 1, wherein the reclaimed BeO washing wastewater membrane clarification device, the raffinate wastewater membrane clarification device, the mixed wastewater membrane clarification device, and the back-end membrane clarification device are all Inorganic membrane filtration device, organic membrane filtration device, roll membrane filtration device, disc membrane filtration device, plate membrane filtration device, hollow fiber membrane filtration device, tubular membrane filtration device, its molecular weight cut off is 5000Da, 8000Da , 10000Da, 30000Da, 50000Da, 80000Da, 100000Da, 150000Da, 200000Da, 250000Da; The purification membranes used in the membrane purification of BeO washing wastewater are inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, disc membrane filtration devices, plate membrane filtration devices, hollow fiber membrane filtration devices, and tubular membrane filtration devices. A kind of, its molecular weight cut off is 5000Da; The purification membranes used in membrane purification of raffinate wastewater are inorganic membrane filtration devices, organic membrane filtration devices, roll membrane filtration devices, disc membrane filtration devices, plate membrane filtration devices, hollow fiber membrane filtration devices, and tubular membrane filtration devices. A kind of molecular weight cut-off of 5000Da, 3000Da, 2500Da, 1000Da, 800Da, 500Da, 300Da, 150Da, 100Da, 50Da, 40Da, 30Da, 20Da; The mixed wastewater is separated by filtration membrane using one of inorganic membrane filtration device, organic membrane filtration device, roll membrane filtration device, disc membrane filtration device, plate membrane filtration device, hollow fiber membrane filtration device and tubular membrane filtration device.

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