CN201952316U - Device for recycling tanning advanced treatment waste water - Google Patents

Abstract

The utility model relates to a tannery advanced treatment waste water recycling device, which relates to waste water treatment. The device is equipped with nano catalytic electrolysis system, submerged ultrafiltration membrane filtration separation system, ultrafiltration membrane cleaning system and electrodialysis system; The ultrafiltration membrane filtration separation system is equipped with a second cut-off valve, submerged ultrafiltration membrane pool, blower, aerator, ultrafiltration membrane system, suction pump and dialysate storage tank; the ultrafiltration membrane cleaning system is equipped with a cleaning fluid tank, Backwash pump, No. 4 cut-off valve and connecting pipeline; Electrodialysis system is equipped with No. 5 cut-off valve, electrodialysis machine, dialysate storage tank and concentrated water storage tank. Based on the combination of nano-catalytic electrolysis technology, submerged ultrafiltration technology and electrodialysis technology, the cost is low and the efficiency is high, so as to achieve the regeneration and recycling of wastewater.

Description

Tannery Advanced Treatment Wastewater Recycling Device

technical field

The utility model relates to a waste water treatment, in particular to a tanning advanced treatment waste water recycling device based on nano-catalyzed electrolysis technology and electrodialysis technology.

Background technique

According to statistics, my country's tanning industry discharges more than 100 million tons of wastewater to the environment every year, accounting for about 0.3% of my country's total industrial wastewater discharge; the output value of the leather industry ranks third in the light industry, second only to papermaking And the brewing industry, it can be seen that the tanning industry not only consumes a large amount of fresh water resources every year, but also discharges a large amount of wastewater, which poses a serious threat to human health and the sustainable development of the entire society. Therefore, the treatment of tannery wastewater should be strengthened, and the treatment of tannery wastewater and the reuse of reclaimed water are very necessary both from the perspective of saving fresh water resources and from the perspective of environmental protection, and have important practical and strategic significance.

The wastewater discharged by the tanning industry has problems such as high concentration of organic pollution, large amount of suspended matter, large water volume, and complex wastewater components, which contain toxic substances such as sulfur and chromium. According to the production process, tannery industrial wastewater is composed of seven parts: raw hide washing water and pickling water with high concentration of chloride, strong alkaline dehairing and liming wastewater containing lime and sodium sulfide, blue chrome tanning wastewater containing trivalent chromium , tea brown vegetable tanning wastewater containing tannin and gallic acid, degreasing wastewater containing oil and its saponification, fatliquoring dyeing wastewater and washing wastewater of various workshops. Among them, degreasing wastewater, dehairing and liming wastewater, and chrome tanning wastewater are the most polluted.

(1) Degreasing wastewater: pigskin production in my country accounts for 80% of tanning production. In the degreasing wastewater produced from pigskin, the oil content is as high as 10,000 (mg/L), and the CODCr is 20,000 (mg/L). Grease wastewater accounts for 4% of the total wastewater, but the oxygen consumption load of grease wastewater accounts for 30% to 40% of the total load.

(2) Dehydration and liming wastewater: Depilation and liming wastewater is a pollution source of sulfide. Wastewater CODCr20000～40000(mg/L), BOD54000(mg/L), sodium sulfide 1200～1500(mg/L), pH 12, dehairing and liming wastewater accounted for 10% of the total wastewater, and the oxygen consumption load accounted for the total load 40%.

(3) Chrome tanning wastewater: Chrome tanning wastewater is a pollution source of trivalent chromium. In the chrome tanning process, the adhesion rate of chromium salt is 60% to 70%, that is, 30% to 40% of chromium salt enters the wastewater. Chrome tanning water Cr3+3000-4000(mg/L), CODCr10000(mg/L), BOD52000mg/L.

The traditional tannery wastewater treatment technology is to collect and mix the wastewater from various processes and put them into the sewage treatment system together. However, because the wastewater contains a large amount of sulfide and chromium ions, it is very easy to inhibit microorganisms. Therefore, at present, it is more reasonable to use the process route of "separate treatment of raw liquid and unified treatment of comprehensive wastewater" [8], to treat degreasing wastewater, liming and dehairing wastewater, and chrome tanning wastewater separately and recover valuable resources, and then mix them with other wastewater Unified processing.

After the wastewater from various channels of the tannery is concentrated, it is called comprehensive tannery wastewater. The content of organic matter, sulfide and chromium in the tannery wastewater is high, and the oxygen consumption is large. The pollution of the wastewater is very serious, mainly in the following aspects aspect:

(1) Chromaticity: leather wastewater has relatively high chromaticity, which is mainly caused by vegetable tanning, dyeing, chrome tanning and gray alkali waste liquid;

(2) Alkaline: The leather wastewater is generally alkaline, and the pH value of the comprehensive wastewater is between 8 and 12. Its alkalinity mainly comes from lime, caustic soda and sodium sulfide used in depilation and other processes;

(3) Sulfides: The sulfides in tannery wastewater mainly come from the ash-alkali hair removal waste liquid, and a small part comes from the immersion waste liquid and protein decomposition products softened by sulfides. Sulfur-containing waste liquid is easy to produce H ₂ S gas when it encounters acid, and sulfur-containing sludge will also release H ₂ S gas under anaerobic conditions;

(4) Chromium ions: Chromium ions in tannery wastewater mainly exist in the form of Cr3+, and the content is generally 100-3000mg/L. Usually, after neutralization and sedimentation, it is filtered and then poured into the comprehensive wastewater pool;

(5) Organic pollutants: The content of organic matter such as protein in tannery wastewater is relatively high, and it also contains a certain amount of reducing substances, so BOD5 and CODCr are very high.

The quality of wastewater discharged from each section of the tanning process varies greatly. After the wastewater discharged from each section is collected, the pH of the comprehensive wastewater is between 8 and 12, and the concentration of chroma, CODCr, SS, and BOD5 is very high. Toxic and harmful substances and The concentration of salts is also very high. See the table below for the comprehensive wastewater quality (test average) of the tannery industry.

pH Chromaticity (times) CODCr SS NH ₃ -N S ^2- Cr BOD5 8～12 500～3500 3000～4000 2000～4000 250～300 50～100 100～3000 1500～2000

Note: The unit is mg/L except for pH and chroma

At present, the methods used for tannery wastewater treatment mainly include: coagulation precipitation method, adsorption method, advanced oxidation method, direct recycling method, air flotation method, acid absorption method, catalytic oxidation method, biochemical method, etc., each method Both have various advantages and disadvantages. Because a single treatment method is difficult to achieve the effect, in practical applications, several methods are usually combined according to the actual situation of the wastewater to be treated. Huang Zhenxiong introduced that a tannery in Guangdong adopts the combined process of flocculation sedimentation-activated sludge method-contact oxidation method to treat tannery wastewater. Since it was put into operation in December 2003, the treatment effect has been stable. About 40mg/L, all effluent indicators have reached the first-level standard of the local standard of Guangdong Province (DB44/26-2001). Zhang Jie et al applied sequencing batch activated sludge process (SBR) to treat wastewater from a tannery in Henan. Firstly, the physicochemical method is used to remove a large amount of toxic substances and some organic matter in the wastewater, and then the SBR method is used to biochemically degrade the soluble organic matter. The designed daily treatment capacity is 800m ³ . When the influent COD is 2500mg/L, the effluent COD is about 100mg/L, which is far below the national standard secondary standard (COD<300mg/L). The operating cost of the project is 0.8 yuan/L Ton. The operation results show that using SBR process to treat tannery wastewater has good adaptability to water quality changes and strong load impact resistance, especially suitable for the relatively concentrated discharge of tannery wastewater and the characteristics of variable water quality. Moreover, the investment of SBR treatment process is relatively low, and the operating cost is lower than that of general activated sludge process. Jia Qiuping used the vortex concave air flotation + two-stage contact oxidation process to transform the wastewater treatment facilities of a tannery in Shenyang City. Not only did the treated wastewater meet the discharge requirements, but the treatment capacity and effect were improved, and 80 % Cr ³⁺ , so that part of the treated wastewater can be reused. When the influent COD is 3647mg/L, after being treated by this process, the effluent COD concentration is 77mg/L, which is lower than the newly expanded secondary standard of "DB21-60-89" in Liaoning Province (COD<100mg/L). Yang Jianjun and Gao Zhongbai introduced that the Xinji City Test Paoying tannery area adopted the physicochemical + oxidation ditch process to transform and increase ^the capacity of the original jet aeration sewage treatment system. Effectively treat wastewater with a COD of about 6100 mg/L. The actual operation shows that the treatment efficiency of the transformation process is high, and the effluent water quality meets the second-level standard of the national "Comprehensive Wastewater Discharge Standard". Tao Rujun introduced that a tanning industrial zone in Zhejiang Province adopts coagulation sedimentation + hydrolysis acidification + CAST process to treat comprehensive wastewater from preparation, tanning and other wet processing sections. The maximum influent flow rate is designed to be 6000m ³ /d. The sulfur ions in the wastewater are pre-aerated, and FeSO ₄ and coagulant PAC are added to the reaction tank to remove them by precipitation. Cr ³⁺ is precipitated and reacted with NaOH in the reaction tank. And removed. The biochemical treatment adopts a combination of facultative and aerobic processes, and the facultative process adopts a contact hydrolysis acidification process, which can improve the biodegradability of wastewater and remove part of COD and SS at the same time. The aerobic CAST process is an improved SBR process, which has the characteristics of high organic matter removal rate and strong impact load resistance. Sun Yabing and others disclosed a method of electrolytic treatment of tannery wastewater in Chinese patent CN100371268C. The COD removal rate of the treated wastewater reached 60% to 80%, the ammonia nitrogen removal rate reached 50% to 70%, and the sulfide removal rate reached 95%. %, the removal rate of suspended solids is 70%-80%, the removal rate of chroma is more than 85%, and the killing rate of Escherichia coli is more than 99%. However, this method has a lot of anode consumption and high energy consumption.

To sum up, the wastewater treated by the existing tannery wastewater treatment method can only meet the discharge standard, but does not meet the industrial wastewater regeneration and recycling standard. Here, the secondary sedimentation tank wastewater that meets the discharge standard after being treated by the existing tannery wastewater treatment method is called tannery advanced treatment wastewater, which has a lot of discharge, a large waste of water resources, high cost, and is likely to cause secondary pollution. Therefore, there is an urgent need for a method for purifying, regenerating and recycling tannery advanced treatment wastewater that consumes less raw materials, can be regenerated and recycled after treatment, and is low in cost and easy to operate, so as to reduce the material consumption per unit product in leather production and save fresh water resources. ,protect environment.

Contents of the invention

The purpose of the utility model is to solve the existing problems in the existing tannery wastewater treatment method, such as large investment in fixed assets, high energy consumption, high regeneration cost of wastewater, low reuse rate, waste of water resources, etc., to provide a Based on the combination of nano-catalytic electrolysis technology, submerged ultrafiltration technology and electrodialysis technology, the cost is low and the efficiency is high, making it a tannery advanced treatment wastewater recycling device for wastewater regeneration and recycling.

The utility model is equipped with a nano-catalysis electrolysis system, a submerged ultrafiltration membrane filtration separation system, an ultrafiltration membrane cleaning system and an electrodialysis system;

The nano-catalysis electrolysis system is used for nano-catalysis electrolysis, precipitation and filtration, etc. The nano-catalysis electrolysis system is provided with a first cut-off valve, a water pump, a nano-catalysis electrolysis machine, a sedimentation tank and a filter device; The outlet of the secondary sedimentation tank of the leather wastewater biochemical treatment system, the inlet of the water pump is connected to the outlet of the first stop valve, the outlet of the water pump is connected to the inlet of the nano-catalyzed electrolyzer, the outlet of the nano-catalyzed electrolyzer is connected to the inlet of the sedimentation tank, and the inlet of the filter device Connect to the outlet of the sedimentation tank;

The submerged ultrafiltration membrane filtration separation system is used to filter and separate the tannery purification wastewater obtained from the nano-catalytic electrolysis system to obtain dialysis water and concentrated water. Membrane pool, blower, aerator, ultrafiltration membrane system, suction pump and dialysate storage tank, the submerged ultrafiltration membrane pool is connected to the outlet of the sedimentation tank of the nanocatalytic electrolysis system through the water inlet pipe and the second shut-off valve , the ultrafiltration membrane of the ultrafiltration membrane system is immersed in the tannery purification wastewater in the submerged ultrafiltration membrane pool, the suction pump sucks the water through the membrane wall from the inside of the ultrafiltration membrane under negative pressure, and the dialysis water produced is passed through the suction The pump collects the dialysate storage tank for further electrodialysis desalination to obtain regenerated water for recycling in production. The outlet of the submerged ultrafiltration membrane pool passes through the suction pump and the third stop valve to connect to the dialysate storage tank in sequence;

The ultrafiltration membrane cleaning system is used to clean the ultrafiltration membrane filtration separation system. The ultrafiltration membrane cleaning system is provided with a cleaning liquid tank, a backwash pump, the 4th shut-off valve and a connecting pipeline, and the outlet of the cleaning liquid tank is connected to the backwash pump. The inlet and the outlet of the backwash pump are connected to the inlet of the fourth stop valve, and the outlet of the fourth stop valve is connected to the ultrafiltration membrane system of the submerged ultrafiltration membrane filtration separation system;

The electrodialysis system is provided with the 5th stop valve, electrodialysis machine, dialysate storage tank and concentrated water storage tank, the outlet of the 5th stop valve is connected to the outlet of the submerged ultrafiltration membrane pool of the submerged ultrafiltration membrane filtration separation system , the water inlet of the electrodialysis machine is connected to the outlet of the fifth stop valve, the dialysis water outlet of the electrodialysis machine is connected to the dialysate storage tank, and the concentrated water outlet of the electrodialysis machine is connected to the concentrated water storage tank.

The filtration can be sand filtration, multimedia filtration or microfiltration.

The submerged ultrafiltration membrane filtration system can remove solid impurities, plankton, bacteria, colloids, etc. in wastewater. The submerged membrane adopts an external pressure open filtration design and can be directly immersed in wastewater, so the system occupies an area of Small. Its working conditions are: room temperature ~ 45 ℃, working pressure 3 ~ 50kPa.

The electrodialysis system can adopt inverted electrodialysis system (EDR), liquid membrane electrodialysis system (EDLM), filled electrodialysis system (EDI), bipolar electrodialysis system (EDMB) or electrodeless hydrodialysis system etc.; The electrodialysis system can separate the dialysis water obtained through the submerged ultrafiltration membrane filtration separation system into dialysis water (de-salted water) and concentrated water through electrodialysis, so that it can meet the quality requirements of different production process water in industrial production. The working condition of electrodialysis is 0.5-3.0kg/cm ² , the operating voltage is 50-250V, and the current intensity is 1-3A. The electrodialysis system can perform one-stage desalination, two-stage desalination or three-stage desalination according to the salt content in the wastewater, so that the salt content of the regenerated water meets the process water requirements for industrial production, and its desalination rate can reach 45% to 80%. .

The electrodialysis system can adopt one-stage electrodialysis system, two-stage electrodialysis system, three-stage electrodialysis system and four-stage electrodialysis system.

Adopting the utility model can carry out tannery advanced treatment wastewater recycling, and the specific method includes the following steps:

1) Nano-catalyzed electrolysis: After biochemical treatment, the tanning advanced treatment wastewater in the secondary sedimentation tank is extracted by the water pump, and then input into the nano-catalytic electrolysis machine for nano-catalytic electrolysis, and then enters the sedimentation tank through the valve for precipitation, and then enters the filter device for filtration. Remove solid impurities, plankton, bacteria, and colloids produced by nano-catalytic electrolysis in wastewater to purify wastewater.

2) Submerged ultrafiltration filtration: The purified tannery wastewater treated by the nano-catalytic electrolysis system flows into the submerged ultrafiltration system through the pipeline for ultrafiltration membrane filtration to obtain dialysis water.

3) Electrodialysis: The purified tannery wastewater treated by the submerged ultrafiltration system is pumped into the electrodialysis system for desalination by electrodialysis to obtain desalted water and concentrated water.

In step 1), the working voltage of the nano-catalyzed electrolysis can be 2-250V, the voltage between two adjacent electrodes can be 2-18V, the optimal voltage between two adjacent electrodes is 3-8V, and the current The density can be 10-280mA/cm ² , and the best current density is 50-230mA/cm ² . The advanced treatment wastewater of tannery is electrolyzed and flows into the sedimentation tank through the valve.

The sodium chloride content of the tanning wastewater can be 6‰-30‰, preferably 0.6‰-1.3‰. If the sodium chloride content is not enough, industrial sodium chloride can be added to supplement it to 6‰-30‰.

The nano-catalytic electrolysis is to generate nascent chlorine [Cl], hydroxyl and nascent oxygen [O] through nano-catalyzed electrolysis of tannery advanced treatment wastewater, which is used to oxidize and decompose organic matter and ammonia nitrogen in wastewater, and kill Kill the microorganisms in the wastewater, and at the same time, under the action of the electric field, the suspended solids, colloids, and charged particles in the wastewater are agglomerated to form larger particles.

In step 2), the working conditions of the ultrafiltration membrane filtration may be: normal temperature to 45° C., working pressure of 3 to 50 kPa.

In step 3), the working conditions of the electrodialysis system may be: 0.5-3.0 kg/cm ² , operating voltage 50-250V, and current intensity 1-3A.

The dialyzed water is used in softening and dyeing processes in tanning production, and the concentrated water is used in rinsing and liming processes in tanning production. Therefore, the waste water can be completely regenerated and recycled.

Compared with the double-membrane method (ultrafiltration+reverse osmosis or ultrafiltration+nanofiltration) treatment method, the utility model not only overcomes the defect of high cost, but also overcomes the unsatisfactory wastewater treatment effect, the discharged wastewater pollutes the environment and defects, and can turn decay into spirit, turn waste into resources, purify and recycle the existing tannery advanced treatment wastewater, and has the following outstanding advantages:

1. High water recovery rate and low cost The water recovery rate is as high as 85% to 100%, less waste water discharge, low energy consumption, and the operating cost is lower than the cost of traditional biochemical terminal double-membrane filtration treatment technology, per ton of water (reuse water) The cost is much lower than the current tap water price;

2. Good decolorization effect It quickly oxidizes and decomposes the colored substances in the wastewater, and the decolorization effect is good. For example: when the chromaticity of the wastewater in the secondary sedimentation tank is 200, the chromaticity is less than 8 after being treated by a nano-catalyzed electrolytic machine;

3. Significantly reduce the total discharge of wastewater COD. Although the traditional biochemical end-membrane filtration technology can realize partial reuse of reclaimed water, it cannot reduce the total discharge of wastewater COD. The utility model can quickly oxidize and decompose organic matter in wastewater , significantly reducing the total discharge of wastewater COD;

4. Eradication of membrane biofouling can kill bacteria in wastewater, eradicate membrane biofouling, greatly reduce membrane cleaning times, reduce membrane cleaning and regeneration costs, improve membrane usage efficiency, prolong membrane life, and reduce membrane replacement cost;

5. There is no secondary pollution. Nano catalytic electrolysis technology is used to replace the physical and chemical treatment process of secondary sedimentation tank wastewater without adding flocculants, decolorizers, air flotation agents and other chemical substances, which not only saves costs, but also saves material consumption and does not produce secondary secondary pollution;

6. Significantly reduce sludge When the utility model is used to treat wastewater, nano-catalyzed electrolysis technology is used to replace the physical and chemical process after the water is discharged from the secondary sedimentation tank, without adding flocculant, decolorizer and other chemical substances, and the sludge is only half of the traditional technology one;

7. Less land occupation, short production process, compact equipment structure and less land occupation;

8. Recycled water is of high quality, colorless and odorless, and the water quality is much higher than the standard of GB/T19923-2005 "Water Quality for Urban Sewage Recycled Water Utilization Industry";

9. Replacing reverse osmosis desalination or nanofiltration desalination with electrodialysis desalination, the investment in fixed assets is greatly reduced, and the energy consumption during equipment operation is greatly reduced.

The use of nano-catalyzed electrolysis has the following outstanding effects: (1) Use the nascent chlorine [Cl], hydroxyl and nascent oxygen [O] produced by nano-catalyzed electrolysis to kill microorganisms in wastewater, reducing the number of microorganisms in wastewater to 30/ Below ml, to eliminate microbial contamination of membrane materials. (2) Oxidize and decompose the ammonia nitrogen in the wastewater to further oxidize the residual ammonia nitrogen, and the removal rate of ammonia nitrogen can reach 60-90%. (3) Significantly reduce the chromaticity of wastewater. After biochemical, physical and chemical treatment, the chromaticity of the tanning advanced treatment wastewater in the secondary sedimentation tank is between 60 and 200. It is difficult to further decolorize by general treatment methods , After nano-catalyzed electrolysis, the chromaticity of tannery advanced treatment wastewater can be reduced from 60 to 200 to 1 to 8. (4) Oxidize and decompose the organic matter in the wastewater, and the residual dye quickly reduces COD _Cr . (5) After the suspended solids, colloids, and charged particles in the wastewater are condensed under the action of an electric field to form larger particles, they are filtered and removed to obtain purified wastewater. (6) The heavy metal ions in the wastewater move to the cathode of the electrolytic cell of the electrolyzer and form a precipitate at the cathode, thereby reducing the content of heavy metal ions in the wastewater.

Description of drawings

Fig. 1 is a schematic diagram of the structure and composition of an embodiment of the utility model.

Detailed ways

The utility model is a process design for the purification and recycling of the advanced treatment wastewater of the tannery after the in-depth and systematic comparative study of the components, properties and existing treatment schemes of the advanced treatment wastewater of the tannery industry. The combination of catalytic electrolysis, precipitation, filtration, immersion ultrafiltration and electrodialysis forms a device and method that is especially suitable for the purification and recycling of tannery advanced treatment wastewater.

The following embodiments will further illustrate the utility model in conjunction with the accompanying drawings.

Referring to Fig. 1, the utility model embodiment is provided with:

Nano catalytic electrolysis system: The nano catalytic electrolysis system is used for nano catalytic electrolysis, precipitation and other processing steps. The nano-catalysis electrolysis system is provided with stop valve 11, water supply pump 12, nano-catalysis electrolysis machine 13, sedimentation tank 14; The outlet, the outlet of the water supply pump 12 is connected to the inlet of the nano-catalysis electrolysis machine 13, and the outlet of the nano-catalysis electrolysis tank 13 is connected to the inlet of the sedimentation tank 14.

Submerged ultrafiltration membrane filtration separation system: The submerged ultrafiltration membrane filtration separation system is used to filter and separate the tannery purification wastewater obtained from the nano-catalytic electrolysis system to obtain dialysate (water) and concentrate; the submerged ultrafiltration membrane filtration separation system Be provided with stop valve 21, ultrafiltration membrane system 22, air blower 23, aerator 24, submerged ultrafiltration membrane pool 25, suction pump 26, stop valve 27 and dialysate (water) storage tank 28; The inlet is connected to the outlet of the sedimentation tank 14 of the nanocatalytic electrolysis system, the outlet of the stop valve 21 is connected to the inlet of the submerged ultrafiltration membrane pool 25, and the outlet of the submerged ultrafiltration membrane pool 25 enters the dialysate through the suction pump 26 and the shut-off valve 27 in turn (water) storage tank 28.

Ultrafiltration membrane cleaning system: the ultrafiltration membrane cleaning system is used to clean the ultrafiltration membrane filtration separation system, and is equipped with a cleaning liquid tank 31, a backwash pump 32, and a stop valve 33; the outlet of the cleaning liquid tank 31 is connected to the inlet of the backwash pump 32 , the outlet of the backwash pump 32 is connected to the inlet of the stop valve 33 , and the outlet of the stop valve 33 is connected to the ultrafiltration membrane system 22 .

Electrodialysis system: The electrodialysis system is equipped with a stop valve 41 , a water supply pump 42 , an electrodialysis machine 43 , a dialysate (water) storage tank 44 , and a concentrated solution storage tank 45 . The electrodialysis machine is provided with a water inlet, a dialysate (water) outlet, and a concentrated water outlet. The tannery purified wastewater obtained by the submerged ultrafiltration system enters the electrodialysis machine 43 through the shut-off valve 41 and the water supply pump 42, and is separated into the dialysate (water) and concentrated liquid through the electrodialysis machine, and the dialysate (water) passes through the dialysate (water) The outlet is stored in the dialysate (water) storage tank 44, and the concentrated solution is stored in the concentrated solution storage tank 45 through the concentrated water outlet; the dialyzed water is used for soft leather and dyeing processes in the leather production, and the concentrated water is used in the leather production Peeling and liming process.

The method for purifying, regenerating and recycling tannery wastewater using the embodiment of the tannery advanced treatment wastewater purification device shown in FIG. 1 is given below.

Example 1

150 tons/day tannery advanced treatment wastewater purification regeneration and recycling method.

The measured indexes of the printing and dyeing advanced treatment wastewater are shown in Table 1.

Table 1

serial number project unit measured value serial number project unit measured value 1 COD _Cr mg/L 130 5 Ammonia nitrogen mg/L 3.8 2 SS mg/L 25 6 Salt content ‰ 7.6 3 Turbidity NTU 9 7 pH 8.1 4 Chroma 80 8 Conductivity μS/cm 2350

150 tons of tannery advanced treatment wastewater is extracted by the water supply pump at a flow rate of 7.5T/h, and then input into the nano-catalytic electrolysis machine. The nano-catalytic electrolyzed water directly enters the sedimentation tank, and after precipitation, it enters the submerged ultrafiltration membrane system to remove solid impurities in the water. Plankton, bacteria, and colloids can purify wastewater.

The working voltage of the nano-catalytic electrolysis is 8-9V, and the current intensity is 500-510A. The nascent chlorine [Cl], hydroxyl and nascent oxygen [O] produced by the nano-catalytic electrolysis can kill microorganisms in wastewater, oxidize and decompose The organic matter in the wastewater, and the suspended solids, colloids, and charged particles in the wastewater are formed into larger particles under the action of an electric field, and then are removed by the submerged ultrafiltration membrane filtration separation system to purify the wastewater. The measured SDI is 0.9.

The purified wastewater purified by the nano-catalytic electrolysis unit and the submerged ultrafiltration membrane filtration separation system enters the electrodialysis machine through the stop valve, water supply pump and water inlet for electrodialysis desalination treatment, and is separated into dialysis water and concentrated water, and the dialysis water passes through The dialysis water outlet and the pipeline enter the dialysis fluid storage tank, and the concentrated water enters the concentrated water storage tank through the concentrated water outlet and the pipeline.

The electrodialysis system is an inverted electrode electrodialysis system (EDR), and the working condition of the electrodialysis is 0.5kg/cm ² , the operating voltage is 50-250V, and the current intensity is 1-3A.

The flow rates of the dialysis water and the concentrated solution are 7T/h and 1.0T/h respectively, the dialysis water is used for soft leather and dyeing process in tanning production, and the concentrated water is used for rinsing and liming process in tanning production , the recovery rate of wastewater is 100%, the quality of recycled water is shown in Table 2, and the index of concentrated wastewater is shown in Table 3.

Table 2

serial number project unit measured value serial number project unit measured value 1 COD _Cr mg/L 19 4 Chroma 1 2 SS mg/L not detected 5 pH 6.7 3 Turbidity NTU 1.1 6 Conductivity μS/cm 420

table 3

serial number project unit measured value serial number project unit measured value 1 COD _Cr mg/L 88 5 Salt content ‰ 1.8 2 SS mg/L 25 6 pH 8.5 3 Turbidity NTU 2.5 7 Conductivity μS/cm 3900 4 Chroma 8

Example 2

3000 tons/day tannery advanced treatment wastewater purification regeneration and recycling method.

The indicators of the advanced treatment of tannery wastewater after determination are shown in Table 4:

Table 4

serial number project unit measured value serial number project unit measured value 1 COD _Cr mg/L 56 5 Salt content ‰ 0.6

2 SS mg/L 11 6 pH 7.7 3 Turbidity NTU 6 7 Conductivity μS/cm 1100 4 Chroma 60

After being extracted by the water supply pump at a flow rate of 150T/h, the advanced treatment wastewater of tannery is input into the nano-catalytic electrolysis tank, and the nano-catalytic electrolyzed water directly enters the sedimentation tank, and after neutralization and precipitation, the solid impurities, plankton, and Bacteria and colloids can purify wastewater.

Due to the low salt content of the tannery advanced treatment wastewater, industrial sodium chloride is first added to adjust its salt content to 8.5‰, and then nano-catalytic electrolysis is performed. The working voltage of nano-catalytic electrolysis is 5-6V, and the current intensity 1560~1580A, nano-catalyzed electrolysis produces nascent chlorine [Cl], hydroxyl and nascent oxygen [O] to kill microorganisms in wastewater, oxidize and decompose organic matter in wastewater, and make suspended solids, colloids, After the charged particles form larger particles under the action of the electric field, they are removed by the submerged ultrafiltration membrane filtration separation system to purify the wastewater, and the measured SDI is 1.3.

The purified wastewater purified by the nano-catalytic electrolysis unit and the submerged ultrafiltration membrane filtration separation unit enters the electrodialysis machine through the stop valve, water supply pump and water inlet for electrodialysis desalination treatment, and is separated into dialysis water and concentrated water, and dialysis water The dialysate storage tank enters through the dialysis water outlet and the pipeline, and the concentrated water enters the concentrated water storage tank through the concentrated water outlet and the pipeline.

The electrodialysis system is a filled electrodialysis system (EDI), and the working conditions of the electrodialysis are operating voltage 3.0kg/cm ² , operating voltage 150-250V, and current intensity 2-3A.

The flow rates of the dialysis water and concentrated water are 105T/h and 45T/h respectively, the dialysis water is used for soft leather and dyeing process in tanning production, and the concentrated water is used for leather washing and liming process in tanning production, The recovery rate of waste water is 100%, the quality of recycled water is shown in Table 5, and the indicators of concentrated waste water are shown in Table 6.

table 5

serial number project unit measured value serial number project unit measured value 1 COD _Cr mg/L 19 4 Chroma 1 2 SS mg/L not detected 5 pH 7.1 3 Turbidity NTU 1.1 6 Conductivity μS/cm 359

Table 6

serial number project unit measured value serial number project unit measured value 1 COD _Cr mg/L 75 4 Salt content ‰ 15.5 2 SS mg/L 38 5 pH 7.9

3 Turbidity NTU 2.6 6 Conductivity μS/cm 3200

Example 3

6000 tons/day tannery advanced treatment wastewater purification regeneration and recycling method.

The indicators of the purification, regeneration and recycling device for the advanced treatment of tannery wastewater are shown in Table 7.

Table 7

serial number project unit measured value serial number project unit measured value 1 COD _Cr mg/L 91 4 Salt content ‰ 0.9 2 SS mg/L twenty two 5 pH 7.7 3 Turbidity NTU 7.4 6 Conductivity μS/cm 3100

After being extracted by the water supply pump at a flow rate of 300T/h, the advanced treatment wastewater of tannery is input into the nano-catalysis electrolysis tank, and the nano-catalysis electrolysis water directly enters the sedimentation tank, and after precipitation, the solid impurities, plankton, and Bacteria and colloids can purify wastewater.

The tannery advanced treatment wastewater has a low salt content, the working voltage of the nano-catalyzed electrolysis is 12-13V, and the current intensity is 3760-3800A. The nascent chlorine [Cl], hydroxyl, and nascent oxygen [O] produced by nano-catalytic electrolysis kill microorganisms in wastewater, oxidize and decompose organic matter in wastewater, and make suspended solids, colloids, and charged particles in wastewater act in an electric field After the larger particles are formed, they are removed by the submerged ultrafiltration membrane filtration separation system to purify the waste water, and the measured SDI is 1.3.

The purified wastewater purified by the nano-catalytic electrolysis unit and the submerged ultrafiltration membrane filtration separation unit enters the electrodialysis machine through the stop valve, water supply pump and water inlet for electrodialysis desalination treatment, and is separated into dialysis water and concentrated water, and dialysis water The dialysate storage tank enters through the dialysis water outlet and the pipeline, and the concentrated water enters the concentrated water storage tank through the concentrated water outlet and the pipeline.

The electrodialysis system is a bipolar electrodialysis system (EDMB), and the working conditions of the electrodialysis are operating voltage 2.3kg/cm ² , operating voltage 190-250V, and current intensity 2-3A.

The flow rates of the dialysis water and the concentrated water are 255T/h and 45T/h respectively, the dialysis water is used for soft leather and dyeing process in the tanning production, and the concentrated water is used for the washing and liming process in the tanning production, The recovery rate of wastewater is 100%, the quality of reused water is shown in Table 8, and the indicators of concentrated wastewater are shown in Table 9.

Table 8

serial number project unit measured value serial number project unit measured value 1 COD _Cr mg/L twenty one 4 Chroma 1 2 SS mg/L not detected 5 pH 7.3 3 Turbidity NTU 1.3 6 Conductivity μS/cm 480

Table 9

serial number project unit measured value serial number project unit measured value 1 COD _Cr mg/L 96 5 Salt content ‰ 2.7 2 SS mg/L 15 6 pH 7.9 3 Turbidity NTU 3 7 Conductivity μS/cm 4500 4 Chroma 8

Claims (4)

1. The tannery advanced treatment wastewater recycling device is characterized in that it is equipped with a nano-catalyzed electrolysis system, a submerged ultrafiltration membrane filtration separation system, an ultrafiltration membrane cleaning system and an electrodialysis system; The nano-catalysis electrolysis system is used for nano-catalysis electrolysis, precipitation and filtration treatment. The nano-catalysis electrolysis system is provided with a first stop valve, a water pump, a nano-catalysis electrolysis machine, a sedimentation tank and a filter device; the import of the first stop valve is externally connected to the tannery The outlet of the secondary settling tank of the wastewater biochemical treatment system, the inlet of the water pump is connected to the outlet of the first stop valve, the outlet of the water pump is connected to the inlet of the nano-catalyzed electrolyzer, the outlet of the nano-catalyzed electrolyzer is connected to the inlet of the sedimentation tank, and the inlet of the filter device is connected to the outlet of the settling tank; The submerged ultrafiltration membrane filtration separation system is used to filter and separate the tannery purification wastewater obtained from the nano-catalytic electrolysis system to obtain dialysis water and concentrated water. Membrane pool, blower, aerator, ultrafiltration membrane system, suction pump and dialysate storage tank, the submerged ultrafiltration membrane pool is connected to the outlet of the sedimentation tank of the nanocatalytic electrolysis system through the water inlet pipe and the second shut-off valve , the ultrafiltration membrane of the ultrafiltration membrane system is immersed in the tannery purification wastewater in the submerged ultrafiltration membrane pool, the suction pump sucks the water through the membrane wall from the inside of the ultrafiltration membrane under negative pressure, and the dialysis water produced is passed through the suction The pump collects the dialysate storage tank for further electrodialysis desalination to obtain regenerated water for recycling in production. The outlet of the submerged ultrafiltration membrane pool passes through the suction pump and the third stop valve to connect to the dialysate storage tank in sequence; The ultrafiltration membrane cleaning system is used to clean the ultrafiltration membrane filtration separation system. The ultrafiltration membrane cleaning system is provided with a cleaning liquid tank, a backwash pump, the 4th shut-off valve and a connecting pipeline, and the outlet of the cleaning liquid tank is connected to the backwash pump. The inlet and the outlet of the backwash pump are connected to the inlet of the fourth stop valve, and the outlet of the fourth stop valve is connected to the ultrafiltration membrane system of the submerged ultrafiltration membrane filtration separation system; The electrodialysis system is provided with the 5th stop valve, electrodialysis machine, dialysate storage tank and concentrated water storage tank, the outlet of the 5th stop valve is connected to the outlet of the submerged ultrafiltration membrane pool of the submerged ultrafiltration membrane filtration separation system , the water inlet of the electrodialysis machine is connected to the outlet of the fifth stop valve, the dialysis water outlet of the electrodialysis machine is connected to the dialysate storage tank, and the concentrated water outlet of the electrodialysis machine is connected to the concentrated water storage tank. 2. The tannery advanced treatment wastewater recycling device according to claim 1, characterized in that the working conditions of the submerged ultrafiltration membrane filtration system are: normal temperature to 45° C., and working pressure of 3 to 50 kPa. 3. The tannery advanced treatment waste water recycling device as claimed in claim 1, characterized in that the electrodialysis system adopts an inverted electrodialysis system, a liquid membrane electrodialysis system, a filled electrodialysis system, and a bipolar electrodialysis system Or electrodeless hydrodialysis system. 4. The tannery advanced treatment wastewater recycling device according to claim 1, characterized in that the working conditions of the electrodialysis system are 0.5-3.0kg/cm ² , operating voltage 50-250V, and current intensity 1-3A.

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