CN108033591A - A kind of coagulation-ozone oxidation combination carries out VB12The device and method of Wastewater Pretreatment - Google Patents

Abstract

The invention discloses a coagulation-ozone oxidation combined device and method for pretreatment of VB ₁₂ wastewater. The device mainly includes a pH adjustment tank one, a coagulation tank, a sedimentation tank, a pH adjustment tank two, an ozone oxidation tower, and a PLC Control device, sludge treatment device and water inlet pump; the water in the pH adjustment tank 1 is pumped to the coagulation tank through the water inlet pump; the water in the coagulation tank is pumped to the sedimentation tank through the water inlet pump; The water is pumped to the pH adjustment tank 2; the water in the pH adjustment tank 2 is pumped to the ozone oxidation tower through the water inlet pump; the PLC control device is connected to the electrical appliances used through the wire; the sludge treatment device is connected to the pH adjustment tank 1, the coagulation tank, and the sedimentation tank , two connection of pH adjusting pool; described method comprises: adjusting pH; Coagulation; Precipitation; Oxidation pretreatment; _Ozone oxidation; out of the water.

Description

A device and method for coagulation-ozonation combined pretreatment of VB12 wastewater

technical field

The invention relates to the technical field of sewage treatment, in particular to a coagulation-ozone oxidation combined device and method for VB ₁₂ wastewater pretreatment.

Background technique

Vitamin B ₁₂ , referred to as VB ₁₂ , is a B vitamin composed of cobalt-containing porphyrin compounds. It can be used to treat various VB ₁₂ deficiencies, and can also be used as a feed additive and food coloring agent. In the industrial production of VB ₁₂ , it is mainly synthesized by aerobic or anaerobic fermentation by Propionibacterium fischeri or Pseudomonas denitrification. The VB ₁₂ produced by Propionibacterium fischeri is concentrated in the cell, and the VB ₁₂ produced by Pseudomonas denitrification is distributed inside and outside the cell, and VB ₁₂ can be obtained by extraction. During the process of fermentation, extraction, conversion, and refining into VB ₁₂ products, a large amount of wastewater is produced, mainly including fermentation waste liquid, wastewater from extraction and refining processes, tank washing water, ground washing water, etc. VB ₁₂ production wastewater contains culture medium residues, macromolecular proteins, ketones, propionic acid, dimethylbenzimidazole and other refractory substances, with COD as high as 10,000mg/L, and high chroma and salinity.

VB ₁₂ wastewater belongs to fermentation wastewater. Before 2008, the discharge limit of fermentation wastewater pollutants was in accordance with the provisions of the "Comprehensive Discharge Standard for Wastewater" (GB8978-1996), requiring COD≤300mg/L and chroma≤80 times. In 2008, the Ministry of Environmental Protection promulgated the "Discharge Standard of Water Pollutants for Fermentation Pharmaceutical Industry" (GB21903-2008), which stipulates that all enterprises must implement the new standard from July 1, 2010. Among them, it is required that the effluent COD≤120mg/L and the chroma≤60 times. Most of the VB ₁₂ wastewater treatment processes in actual projects are anaerobic-aerobic biological treatment, but the effluent of this process sometimes cannot even meet the COD≤300mg/L regulation in the "Comprehensive Wastewater Discharge Standard" (GB8978-1996). In response to this problem, researchers have carried out related research. Xing Yi et al used micro-electrolysis-bentonite and PAC co-adsorption coagulation treatment of VB ₁₂ production wastewater, raw water COD22000mg/L, micro-electrolysis 10min, bentonite dosage 15g/L, PAC dosage 10g/L, COD and chroma removal The rate can reach 71% and 88% respectively, the COD of the effluent is about 6000mg/L, and the effluent can be further treated by biological methods. From the perspective of pretreatment, this method reduces the load of subsequent biological treatment through physical and chemical methods, but the dosage of chemicals is large, and a large amount of sludge will be generated. Feng Fei et al. used micro-electrolysis-MBR process to treat VB ₁₂ anaerobic treatment effluent. The influent COD was 1600-2200mg/L, the micro-electrolysis reaction pH was 2, the reaction time was 1h, the carbon-iron ratio was 2, and the MBR sludge concentration was 6. —8g/L, when the residence time is 20h and DO is 2mg/L, the effluent COD is less than 300mg/L. Most of the actual projects use biological methods to treat VB ₁₂ wastewater, so it is more practical to further treat the VB ₁₂ wastewater after biological treatment.

The secondary effluent of VB ₁₂ has poor biochemical properties and organic matter is difficult to degrade, so it is suitable for chemical treatment. However, the cost of chemical treatment is high and there is secondary pollution.

Contents of the invention

In view of the above-mentioned problems, the present invention provides a device for pretreatment of VB ₁₂ wastewater by a combination of coagulation-ozone oxidation. Another technical problem solved by the present invention is to provide a combination of coagulation-ozone oxidation for VB ₁₂ Methods of wastewater pretreatment.

In order to solve the above-mentioned first technical problem, the technical solution of the present invention is: a kind of coagulation-ozone oxidation combination carries out the device of VB ₁₂ waste water pretreatment, mainly comprises pH adjustment tank 1, coagulation tank, sedimentation tank, pH adjustment tank Two, ozonation tower, PLC control device, sludge treatment device and water inlet pump; Described water inlet pump comprises water inlet pump one, water inlet pump two, water inlet pump three and water inlet pump four; Described pH adjusting tank one, coagulation tank, Both the sedimentation tank and the bottom of the pH adjustment tank are provided with an electronic vent valve; the coagulation tank is connected to the pH adjustment tank one, and the water in the pH adjustment tank one is pumped to the coagulation tank through the inlet pump one; The pool is connected to the coagulation tank, and the water in the coagulation tank is pumped to the sedimentation tank through the inlet pump two; the pH adjustment tank two is connected to the sedimentation tank, and the water in the sedimentation tank is pumped to pH through the inlet pump three Adjustment tank two; the ozone oxidation tower is connected with the pH adjustment tank two, and the water in the pH adjustment tank two is pumped to the ozone oxidation tower through the water inlet pump four; the coagulation tank is provided with a dosing pump, and the inside of the coagulation tank A partition plate, a high-speed stirring device and a low-speed stirring device are provided. The partition plate is arranged at the bottom of the coagulation tank close to the water inlet. The partition plate divides the coagulation tank into left and right pool cavities. In the left tank chamber, the low-speed stirring device is arranged in the right tank chamber, and the dosing pump is arranged on the outer wall of the left end of the pool chamber; a mud scraping device is arranged inside the sedimentation tank; the upper end of the ozone oxidation tower is arranged There is an ozone generator, and an aeration device is installed inside the ozone oxidation tower, and the ozone generator is connected to the aeration device through a conduit; the PLC control device is connected to an electronic vent valve, water inlet pump, dosing pump, and high-speed stirring device through a wire , low-speed stirring device, mud scraping device, ozone generator, aeration device, and sludge treatment device are connected; said sludge treatment device is connected to the electronic vent at the bottom of pH adjustment tank one, coagulation tank, sedimentation tank, and pH adjustment tank two valve connection.

Furthermore, both the pH adjustment pool 1 and the pH adjustment pool 2 are equipped with a stirring device and a pH meter inside; the pH adjustment of the wastewater can be effectively performed, and the operation is simpler.

Further, the pipeline connecting the pH adjustment tank 2 and the ozonation tower is provided with a pipeline filtering device.

In order to solve the above-mentioned second technical problem, the technical solution of the present invention is: a kind of coagulation-ozone oxidation combination carries out the method for _VB12 waste water pretreatment, comprises the following steps:

Step 1: Adjust pH

Adjust the pH of the waste water in the pH adjustment tank one; adjust the pH value of the waste water to 4.5;

Step 2: Coagulation

Pump the pH-adjusted waste water from the pH adjustment tank 1 into the coagulation tank through the water inlet pump 1, add the coagulant into the coagulation tank through the dosing pump, and stir through the high-speed stirring device and the low-speed stirring device;

Step 3: Precipitation

The coagulated waste water in the coagulation tank is pumped to the sedimentation tank by the second suction pump for sedimentation; the residence time for sedimentation is 2h;

Step 4: pre-oxidation treatment

Pump the settled waste water from the sedimentation tank to the second pH adjustment tank through the pump three for pH adjustment; adjust the pH value of the waste water to 7;

Step Five: Ozone Oxidation

The pH-adjusted waste water is pumped from the pH adjustment pool 2 to the ozone oxidation tower through the water pump 4, and the ozone is passed into the waste water through the aeration device for oxidation.

Further, the coagulant in step 2 adopts PFS and PACl; PFS is the polyferric sulfate morphological character is the light yellow amorphous powdery solid, very easily soluble in water, the coagulation performance is excellent, the alum flower is dense, and the settling speed is fast; PACl It has the advantages of less dosage, high purification efficiency, good filtered water quality and low cost.

Further, the dosage of coagulant PFS in step 2 is 150mg/L, and the dosage of PACl is 200mg/L; experiments show that the dosage of PFS increases from 50mg/L to 150mg/L, and the removal rate of COD From 1.1% to 30.5%, the removal rate of chroma increased from 21.4% to 60.0%. When the dosage of coagulant is greater than 150mg/L, the removal rate of COD and chroma changes very slowly, so the more suitable dosage of PFS is 150mg/L; the dosage of PACl increases from 50mg/L to 200mg/L , The removal rate of COD increased from 6.6% to 16.0%, and the removal rate of chroma increased from 14.3% to 35.7%. When the dosage of coagulant is greater than 200mg/L, the removal rate of COD and chroma changes slowly, so the optimal dosage of PACl is 200mg/L.

Further, the ozone concentration introduced in step five is 11mg/L.

Further, the reaction time of step five is 1h; when the ozone oxidation time increases from 15min to 60min, the removal rate of COD increases from 8.2% to 36.4%, the removal rate of chroma increases from 40% to 90%, and the COD and color The removal rate increased rapidly. When the ozone oxidation time is longer than 60min, the removal rate of COD and chroma increases slowly. Therefore, the ozone oxidation time can be selected as 60min.

Compared with the prior art, the present invention has the beneficial effects: the coagulation method is a commonly used method in wastewater treatment, not only can be used as a pretreatment process for wastewater treatment, but also can be used as a wastewater advanced treatment process; the ozone oxidation method has a strong The decolorization ability can change the structure of organic matter and improve the biodegradability of wastewater, which has received extensive attention in the advanced treatment of wastewater; the present invention uses coagulation-ozone oxidation to pretreat VB ₁₂ wastewater, and can obtain the best conditions At the same time, the present invention adopts the mixing method of high-speed stirring device and low-speed stirring device in the coagulation tank, adopts high-speed stirring device at the water inlet to quickly mix the sewage and coagulant, and then uses the low-speed stirring device to Complete the coagulation operation, complete the coagulation operation more efficiently, and shorten the time. At the same time, using a low-speed stirring device in the coagulation tank can prevent the impurities after coagulation from settling into the subsequent process.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the influence of pH on PFS coagulation COD and chroma removal rate (PFS is 150mg/L); ● represents COD; ■ represents chroma;

Figure 3 is the effect of PFS dosage on coagulation COD and chroma removal rate (pH=4.5); ● represents COD; ■ represents chroma;

Fig. 4 is the influence of pH on PACl coagulation COD and chroma removal rate (PACl is 150mg/L); ● represents COD; ■ represents chroma;

Figure 5 is the effect of PACl dosage on coagulation COD and chroma removal rate; ● represents COD; ■ represents chroma;

Figure 6 is the effect of ozone oxidation time on COD and chroma removal rate; ● represents COD; ■ represents chroma;

Figure 7 is the effect of pH on the COD removal rate of ozone oxidation; ● represents pH=10; ■ represents pH=7; ▲ represents pH=4;

Figure 8 is the effect of pH on the removal rate of ozone oxidation color; ● represents pH=10; ■ represents pH=7; ▲ represents pH=4;

Fig. 9 is the influence of pH on ozone utilization rate; ● represents pH=10; ■ represents pH=7; ▲ represents pH=4;

Figure 10 is the effect of ozone concentration on the COD removal rate of ozone oxidation; ● represents 11mg/L; ■ represents 18mg/L; ▲ represents 26mg/L;

Figure 11 is the effect of ozone concentration on the removal rate of ozone oxidation color; ● represents 11 mg/L; ■ represents 18 mg/L; ▲ represents 26 mg/L;

Figure 12 is the effect of ozone concentration on ozone utilization rate; ● represents 11 mg/L; ■ represents 18 mg/L; ▲ represents 26 mg/L;

Fig. 13 is a connection block diagram between the PLC control device of the present invention and other electrical devices;

Among them, 1-pH adjustment tank 1, 2-coagulation tank, 20-interval plate, 21-dosing pump, 22-high-speed stirring device, 23-low-speed stirring device, 3-sedimentation tank, 31-sludge scraping device, 4 -pH adjustment tank 2, 40-pipeline filtration device, 5-ozone oxidation tower, 51-ozone generator, 52-aeration device, 6-PLC control device, 7-sludge treatment device, 81-inlet pump 1, 82 -water inlet pump two, 83-water inlet pump three, 84-water inlet pump four.

Detailed ways

Embodiment: a kind of coagulation-ozone oxidation combination as shown in Figure 1 is carried out the device of VB ₁₂ waste water pretreatment, mainly comprises pH adjustment tank one 1, coagulation tank 2, sedimentation tank 3, pH adjustment tank two 4, ozone Oxidation tower 5, PLC control device 6, sludge treatment device 7 and water inlet pump; water inlet pump includes water inlet pump 1, water inlet pump 2 82, water inlet pump 3 83 and water inlet pump 4 84; pH adjustment tank 1, coagulation tank 2. The bottoms of sedimentation tank 3 and pH adjustment tank 24 are all equipped with electronic vent valves; coagulation tank 2 is connected with pH adjustment tank 1, and the water in pH adjustment tank 1 is pumped to the coagulation tank through inlet pump 181 2; the sedimentation tank 3 is connected with the coagulation tank 2, and the water in the coagulation tank 2 is pumped to the sedimentation tank 3 through the inlet pump two 82; the pH adjustment tank two 4 is connected with the sedimentation tank 3, and the sedimentation tank is pumped through the inlet pump three 83 The water of 3 is pumped to pH adjustment pool two 4; Ozone oxidation tower 5 is connected with pH adjustment pool two 4, and the water of pH adjustment pool two 4 is pumped to ozone oxidation tower 5 by inlet pump four 84,

A pipeline filtering device 40 is provided on the pipeline connecting the pH adjustment tank 2 and the ozone oxidation tower 5; a dosing pump 21 is provided on the coagulation tank 2, and a partition plate 20, a high-speed stirring device 22 and a low-speed mixing tank 2 are provided inside the coagulation tank 2. The stirring device 23 and the partition plate 20 are arranged at the bottom of the coagulation tank 2 near the water inlet. The partition plate 20 divides the coagulation tank 2 into left and right pool cavities. The high-speed stirring device 22 is set in the left tank cavity, and the low-speed stirring device 23 is arranged in the right pool chamber, and the dosing pump 21 is arranged on the outer pool wall at the left end of the pool chamber; a mud scraping device 31 is arranged inside the sedimentation tank 3; an ozone generator 51 is arranged at the upper end of the ozone oxidation tower 5, and the inside Aeration device 52 is provided, and ozone generator 51 is connected with aeration device 52 through conduit; The mud device 31, the ozone generator 51, the aeration device 52, and the sludge treatment device 7 are connected; the sludge treatment device 7 is connected to the electronics at the bottom of the pH adjustment tank 1, the coagulation tank 2, the sedimentation tank 3, and the pH adjustment tank 2 4. Vent valve connection.

Among them, the pH adjustment pool 1 and the pH adjustment pool 2 4 are equipped with a stirring device and a pH meter inside; the pH adjustment of the wastewater can be effectively performed, and the operation is simpler.

Using this device to treat the secondary effluent of a VB ₁₂ wastewater in a city with anaerobic-aerobic process, COD: 300-335mg/L, chroma: 350-400 times, the method of VB ₁₂ wastewater pretreatment includes the following steps:

Step 1: Adjust pH

Adjust the pH of the waste water in the pH adjustment pool-1; adjust the pH value of the waste water to 4.5;

Step 2: Coagulation

From the pH adjustment tank-1, the waste water adjusted by the pH value is pumped into the coagulation tank 2 through the water inlet pump-81, and the coagulant is added into the coagulation tank 2 through the dosing pump 21, and passed through the high-speed stirring device 22 and the low-speed mixing tank. Stirring device 23 is stirred; Coagulant adopts PFS and PACl; PFS is that polyferric sulfate morphological character is light yellow amorphous powdery solid, is very soluble in water, and coagulation performance is excellent, and alum flower is dense, and settling speed is fast; PACl It has the advantages of less dosage, high purification efficiency, good water quality after filtration, and low cost; the dosage of coagulant PFS is 150mg/L, and the dosage of PACl is 200mg/L; experiments show that the dosage of PFS Increased from 50mg/L to 150mg/L, the removal rate of COD increased from 1.1% to 30.5%, and the removal rate of chroma increased from 21.4% to 60.0%. When the dosage of coagulant is greater than 150mg/L, the removal rate of COD and chroma changes very slowly, so the more suitable dosage of PFS is 150mg/L; the dosage of PACl increases from 50mg/L to 200mg/L , The removal rate of COD increased from 6.6% to 16.0%, and the removal rate of chroma increased from 14.3% to 35.7%. When the dosage of coagulant is greater than 200mg/L, the removal rate of COD and color changes slowly, so the optimal dosage of PACl is 200mg/L;

Step 3: Precipitation

The coagulated waste water in the coagulation tank 2 is pumped to the sedimentation tank 3 by the water pump 2 82 for sedimentation; the residence time for sedimentation is 2h;

Step 4: pre-oxidation treatment

From the sedimentation tank 3, the settled wastewater is pumped into the pH adjustment tank 2 4 through the water pump 3 83 for pH adjustment; the pH value of the wastewater is adjusted to 7;

Step Five: Ozone Oxidation

From the pH adjustment pool two 4, the waste water adjusted by the pH value is pumped to the ozone oxidation tower 5 by the water pump four 84, and the concentration is that 11mg/L ozone is passed into the waste water for oxidation by the aeration device 52; the reaction time is 1h; When the ozone oxidation time increased from 15min to 60min, the removal rate of COD increased from 8.2% to 36.4%, the removal rate of chroma increased from 40% to 90%, and the removal rate of COD and chroma all increased faster; when ozone When the oxidation time is longer than 60min, the removal rate of COD and chroma increases slowly; therefore, the ozone oxidation time can be selected as 60min.

The treatment results showed that the removal rates of COD and chroma were 59.7% and 95.7%, respectively. The effluent BOD5/COD is 0.27.

Experimental verification:

Figure 2 shows the effect of pH on PFS coagulation removal of COD and chroma when the dosage of PFS is 150mg/L; Figure 2 shows that when the pH is between 3.5 and 8.5, the trend of COD and chroma removal rate is the same; at pH When = 4.5, COD and chroma removal rate reach the maximum value at the same time, which are 30.5% and 60.0% respectively; in the range of pH=6.5-8.5, the coagulation effect is very poor, and the COD removal rate is only about 3%; PFS can be determined The optimum pH for coagulation is 4.5;

Figure 3 shows the effect of PFS dosage on coagulation removal of COD and chroma under the condition of wastewater initial pH=4.5; the dosage of PFS increased from 50mg/L to 150mg/L, and the removal rate of COD increased from 1.1% To 30.5%, the removal rate of chroma increases from 21.4% to 60.0%; when the dosage of coagulant is greater than 150mg/L, the removal rate of COD and chroma changes very slowly, so the more suitable dosage of PFS is 150mg /L;

Figure 4 shows the effect of pH on PACl coagulation removal of COD and chroma when the dosage of PACl is 150mg/L; the removal rate of COD does not change much between pH 3.5 and 8.5, about 12%; chroma The removal rate of PACl is about 32%. From the perspective of treatment effect and cost, the coagulation pH of PACl is determined to be 7.5, that is, there is no need to adjust the pH;

Figure 5 shows the effect of PACl dosage on coagulation removal of COD and chroma under the condition of wastewater initial pH=7.5; the dosage of PACl increased from 50mg/L to 200mg/L, and the removal rate of COD increased from 6.6% To 16.0%, the removal rate of chroma increased from 14.3% to 35.7%; when the dosage of coagulant was greater than 200mg/L, the removal rate of COD and chroma slowed down, so the optimal dosage of PACl was 200mg /L;

Fig. 6 is under the condition of ozone flow rate 100L/h, ozone concentration 11mg/L, waste water pH=7, the influence of ozone oxidation time on COD and chromaticity removal rate; When ozone oxidation time increases from 15min to 60min, COD The removal rate increased from 8.2% to 36.4%, the removal rate of chroma increased from 40% to 90%, and the removal rate of COD and chroma increased rapidly; when the ozone oxidation time was greater than 60min, the removal rate of COD and chroma increased Slow; therefore, the ozone oxidation time can be selected as 60min;

Figure 7 and Figure 8 show the influence of different pH on the removal rate of ozone oxidation COD and chroma under the conditions of ozone flow rate 100L/h and ozone concentration 18mg/L; it can be seen from the figure that the ozone oxidation under the condition of pH=7 The removal rate of COD and chroma is higher than that at pH=4; but the reaction pH increases from 7 to 10, and the removal rate of COD and chroma in ozone oxidation does not change much;

Figure 9 is the ozone utilization rate under different pH conditions, wherein the ozone utilization rate is an instantaneous value, that is, the ratio of the instantaneous inlet and outlet ozone concentration difference to the intake ozone concentration; as can be seen from Figure 9, the ozone utilization rate is relatively high when pH=4 The utilization rate of ozone at pH=7 and pH=10 is low, indicating that the reaction rate between ozone and organic matter is slow at pH=4;

Figure 10 and Figure 11 are under the condition of ozone flow rate 100L/h, ozone oxidation pH=7, the influence of different ozone concentrations on the removal rate of ozone oxidation COD and chroma; As can be seen from Figure 10, ozone oxidation under different ozone concentrations The removal rate of COD increases continuously with the increase of reaction time; when the reaction time is longer than 50min, the change of COD removal rate slows down, so the ozone oxidation reaction time can be selected as 50min; when the reaction time is 50min, the ozone concentration changes from 11mg /L increased to 18mgL, the removal rate of COD by ozone oxidation increased from 36.6% to 42.4%; continue to increase the ozone concentration to 26mg/L, the removal rate of ozone oxidation to COD increased slowly, and only increased to 45.2%; this is because When the ozone concentration in the wastewater reaches a certain limit, the ozone concentration is no longer the limiting factor of the ozone oxidation reaction rate; it can be seen from Figure 11 that the decolorization effect of the ozone oxidation is very good; when the ozone concentration is 11mg/L, the ozone oxidation is 30min 20 minutes before ozone oxidation, the higher the ozone concentration, the faster the decolorization speed; the concentration change after 40 minutes of ozone oxidation has little effect on the decolorization effect;

Figure 12 is the utilization ratio of ozone under different ozone concentrations. It can be seen that the longer the reaction time, the lower the instantaneous utilization ratio of ozone; the higher the ozone concentration, the lower the instantaneous utilization ratio of ozone, and the ozone concentration increases from 11mg/L to 18mg/L When L, the instantaneous utilization rate of ozone dropped from 88.7% to 49.0% when the reaction time was 50 minutes; continue to increase the ozone concentration to 26mg/L, and the instantaneous utilization rate of ozone dropped to 32.0%; the ozone concentration was 11mg/L, and the reaction time was 50min , the ratio of ozone dosage to COD removal is calculated to be 4.17; when the ozone concentration is 18mg/L and the reaction time is 50min, the ratio of ozone dosage to COD removal is 2.087; the ozone concentration is 26mg/L, and the reaction time When it is 50min, the ratio of ozone dosing amount to COD removal amount is 2.96; in order to obtain a higher ozone utilization rate, the ozone concentration is selected to be 11mg/L.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (8)

1. a coagulation-ozone oxidation combination carries out the device of _VB12 waste water pretreatment, is characterized in that, mainly comprises pH adjustment tank one (1), coagulation tank (2), sedimentation tank (3), pH adjustment tank two (4), ozone oxidation tower (5), PLC control device (6), sludge treatment device (7) and water inlet pump; Described water inlet pump comprises water inlet pump one (81), water inlet pump two (82), water inlet pump Three (83) and water inlet pump four (84); the bottoms of the pH adjustment tank one (1), coagulation tank (2), sedimentation tank (3), and pH adjustment tank two (4) are all provided with electronic vent valves; The coagulation tank (2) is connected to the pH adjustment tank one (1), and the water in the pH adjustment tank one (1) is pumped to the coagulation tank (2) by the water inlet pump one (81); The pond (3) is connected with the coagulation pond (2), and the water in the coagulation pond (2) is pumped to the sedimentation pond (3) by the water inlet pump two (82); the pH adjustment pond two (4) is connected with The sedimentation tank (3) is connected, and the water in the sedimentation tank (3) is pumped to the pH adjustment tank two (4) by the water inlet pump three (83); the ozone oxidation tower (5) is connected with the pH adjustment tank two (4) Connect, pump the water of the pH adjustment tank two (4) to the ozone oxidation tower (5) by the water inlet pump four (84); the coagulation tank (2) is provided with a dosing pump (21), coagulation The inside of the pool (2) is provided with a partition plate (20), a high-speed stirring device (22) and a low-speed stirring device (23). (20) The coagulation tank (2) is divided into left and right two tank chambers, the high-speed stirring device (22) is arranged on the left tank chamber, and the low-speed stirring device (23) is arranged on the right tank chamber, and the The dosing pump (21) is arranged on the outer wall of the left end of the pool chamber; the sedimentation tank (3) is provided with a mud scraping device (31); the upper end of the ozone oxidation tower (5) is provided with an ozone generator (51 ), the inside of the ozone oxidation tower (5) is provided with an aeration device (52), and the ozone generator (51) is connected with the aeration device (52) by a conduit; Valve, water inlet pump, dosing pump (21), high-speed stirring device (22), low-speed stirring device (23), mud scraping device (31), ozone generator (51), aeration device (52), sludge treatment The device (7) is connected; the sludge treatment device (7) is connected with the electronic vent valve at the bottom of pH adjustment tank one (1), coagulation tank (2), sedimentation tank (3), pH adjustment tank two (4) . 2. a kind of coagulation-ozone oxidation combination according to claim 1 carries out the device of _VB12 waste water pretreatment, it is characterized in that, described pH adjustment pool one (1) and pH adjustment pool two (4) inside all arrange There is a stirring device and a pH meter. 3. A device for coagulation-ozonation combined pretreatment of VB ₁₂ wastewater according to claim 1, characterized in that a mud scraping device (31) is arranged inside the sedimentation tank (3). 4. a coagulation-ozonation combination carries out the method for _VB12 wastewater pretreatment, is characterized in that, comprises the following steps: Step 1: Adjust pH Adjust the pH of the waste water in the pH adjustment pool one (1); adjust the pH value of the waste water to 4.5; Step 2: Coagulation From the pH adjustment tank one (1), the wastewater adjusted by the pH value is pumped into the coagulation tank (2) through the water inlet pump one (81), and the coagulant is added to the coagulation tank (2) through the dosing pump (21). ), stirred by a high-speed stirring device (22) and a low-speed stirring device (23); Step 3: Precipitation The coagulated waste water in the coagulation tank (2) is pumped to the sedimentation tank (3) by the water pump 2 (82) for sedimentation; the residence time for sedimentation is 2h; Step 4: pre-oxidation treatment From the sedimentation tank (3), the sedimented waste water is pumped into the pH adjustment tank two (4) by the water pump three (83) for pH adjustment; the pH value of the waste water is adjusted to 7; Step Five: Ozone Oxidation The waste water adjusted by the pH value is pumped to the ozone oxidation tower (5) through the water pump four (84) from the pH adjustment pool two (4), and the ozone is passed into the waste water by the aeration device (52) for oxidation. 5. A method for treating chemical sewage by ozone composite catalytic oxidation according to claim 3, wherein the coagulant in step 2 is PFS and PACl. 6. A method for treating chemical sewage by ozone composite catalytic oxidation according to claim 4, characterized in that the dosage of coagulant PFS in step 2 is 150mg/L, and the dosage of PACl is 200mg/L . 7. A method for treating chemical sewage by ozone composite catalytic oxidation according to claim 3, characterized in that the concentration of ozone introduced in step five is 11 mg/L. 8. A method for treating chemical sewage by ozone composite catalytic oxidation according to claim 6, characterized in that the reaction time of the step five is 1 h.