Efficient treatment method for vacuum waste liquid generated in synthetic reaction of polyester resin for powder coating

Abstract

The invention relates to the technical field of wastewater treatment, in particular to an efficient treatment method for vacuum waste liquid generated in synthetic reaction of polyester resin for powder paints.The treatment method comprises the steps that floating oil in the vacuum waste liquid is removed firstly, then sieving treatment is conducted, and then treatment is conducted through an agent 1 obtained by mixing calcium hydroxide, polyaluminum chloride and polyacrylamide; scraping scum to obtain scum-removed waste liquid with relatively low acetaldehyde content; treating the deflotation waste liquid by using an agent 2 obtained by mixing iron powder and modified activated carbon to obtain reduced waste liquid with relatively low heavy metal ion content; adjusting the pH value and the temperature of the reduction waste liquid, treating the reduction waste liquid by using a mixed microbial agent 1, and then treating the reduction waste liquid by using a mixed microbial agent 2 to obtain secondary bacterial degradation waste liquid; treating the secondary bacterial degradation waste liquid by using an agent 3 in cooperation with hydrogen peroxide, and then treating by using an agent 4 to obtain treated vacuum waste liquid of which the contents of ammonia nitrogen and the like are lower than the emission standard. Therefore, the treatment method is high in efficiency, good in effect and wide in application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a high-efficiency treatment method for vacuum waste liquid generated in a synthesis reaction of polyester resin for powder coatings. Background Art

[0002] Powder coating is a solid powdered synthetic resin coating composed of solid resin, pigment, filler and additives. Unlike ordinary solvent-based coatings and water-based coatings, its dispersion medium is air instead of solvent and water. It has the characteristics of no solvent pollution, 100% film formation and low energy consumption. Polyester resin is often used in the preparation of powder coating, but a large amount of vacuum waste liquid is generated in the production process of polyester resin.

[0003] At present, the treatment methods for the large amount of vacuum waste liquid generated during the production of polyester resins are roughly divided into two categories: physical and chemical methods and biochemical methods. Among them, the commonly used physical and chemical methods include coagulation and sedimentation methods, flotation methods, micro-electrolysis methods, etc. The physical and chemical methods generally have short reaction times and high treatment efficiency, but there are problems such as high initial investment, high operating costs, secondary pollution, and complex operations; the biochemical method is divided into anaerobic and aerobic, with low treatment costs, simple operations, and no secondary pollution, but the wastewater B / C is not high, so it is not suitable to directly use the biochemical method. It is necessary to first improve its biodegradability through physical and chemical pretreatment, and a large amount of acetaldehyde in the wastewater also needs to be removed in advance.

[0004] For example, the patent document CN103570191A discloses a polyester resin production wastewater biochemical treatment device and its treatment method. The invention chooses to reduce the acetaldehyde content by diluting the anaerobic tank inlet water with reflux water. Once the final effluent is abnormal, the treatment efficiency of the anaerobic tank cannot be guaranteed; and the internal circulation equipment has a high investment, complex operation, and low efficiency. These prior art methods do not consider how to ensure that the acetaldehyde content can reach a low level before biochemical treatment through physical and chemical pretreatment when the water quality fluctuates greatly, thereby ensuring that the COD of the treated wastewater remains within a stable range, thereby improving the efficiency and effect of wastewater treatment.

[0005] Therefore, according to the above-mentioned related technologies, it is urgent to develop an efficient treatment method for vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating, so as to solve the problems of low efficiency and poor treatment effect of vacuum waste liquid in the prior art.

[0007] Based on the above purpose, the present invention provides a method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating.

[0008] A highly efficient method for treating vacuum waste liquid generated in a polyester resin synthesis reaction for powder coatings comprises the following steps:

[0009] Step S1: After removing the floating oil in the vacuum waste liquid, the waste liquid is sieved, then treated with reagent 1, and then the floating scum is scraped off to obtain the de-floating waste liquid;

[0010] Step S2: treating the deflocculated waste liquid with reagent 2 to obtain reduced waste liquid;

[0011] Step S3: adjusting the pH of the reduced waste liquid to 6.5-7.0 and the temperature to 25-35° C., and then treating it with the mixed bacterial agent 1 to obtain a primary bacterial hydrolysis waste liquid;

[0012] Step S4: treating the primary bacterial hydrolysis waste liquid with mixed bacterial agent 2 to obtain secondary bacterial hydrolysis waste liquid;

[0013] Step S5: treating the secondary bacterial hydrolysis waste liquid with reagent 3 in combination with hydrogen peroxide to obtain oxidized waste liquid;

[0014] Step S6: treating the oxidation waste liquid with reagent 4 to obtain treated vacuum waste liquid;

[0015] The agent 1 is obtained by mixing calcium hydroxide, polyaluminium chloride and polyacrylamide;

[0016] The reagent 2 is obtained by mixing iron powder and modified activated carbon;

[0017] The mixed bacterial agent 1 is obtained by mixing anaerobic enhanced bacteria, anaerobic granular sludge, urea and sodium phosphate;

[0018] The mixed bacterial agent 2 is prepared from aerobic enhanced bacteria and water;

[0019] The agent 3 is prepared from aluminum, titanium, ferrous sulfate, and modified activated carbon;

[0020] The agent 4 is obtained by mixing polyaluminium chloride and polyacrylamide.

[0021] Preferably, the aperture size of the sieve during the screening process in step S1 is 0.06-0.1 mm.

[0022] Preferably, the treatment process of the medicine 1 in step S1 is as follows:

[0023] Calcium hydroxide, polyaluminium chloride, polyacrylamide and water are mixed in a mass ratio of 7-10:5-5.5:2:70-100 to obtain agent A, and then 0.03wt%-0.04wt% of agent 1 is added to the sieved waste liquid, and then stirred until the pH of the waste liquid reaches 1.9-2.1.

[0024] Preferably, the treatment process of the medicine 2 in step S2 is as follows:

[0025] Step B1: heating 90-100 g of 0.1-0.15 mol / L potassium permanganate solution to 55-60° C., adding 15-20 g of activated carbon, reacting with ultrasonic vibration at 55-60° C. for 1-2 h, washing, drying at 75-80° C., and calcining at 300-500° C. for 4-5 h to obtain modified activated carbon;

[0026] The ultrasonic power during the ultrasonic oscillation is 60-70W, and the ultrasonic frequency during the ultrasonic oscillation is 40-45kHz;

[0027] Step B2: Mix iron powder and modified activated carbon in a mass ratio of 7-10:2-4 to obtain reagent 2, then add 30wt%-40wt% of reagent 2 to the deflocculated waste liquid, stir and react for 2-3h to obtain reduced waste liquid.

[0028] Preferably, the mixed bacterial agent 1 treatment process in step S3 is as follows:

[0029] The anaerobic enhanced bacteria and water are mixed and then allowed to stand for 2-5 days, and then anaerobic granular sludge, urea and sodium phosphate are added to obtain a mixed bacterial agent 1, and then 8.4wt%-10wt% of the mixed bacterial agent 1 is added to the reduced waste liquid and allowed to stand for 1.5-3 days to obtain a primary bacterial hydrolysis waste liquid;

[0030] The mass ratio of the anaerobic strengthening bacteria, water, anaerobic granular sludge, urea and sodium phosphate is 5-7:10-15:0.3-0.5:5.4-6:4.5-5.

[0031] Preferably, the mixed bacterial agent 2 treatment process in step S4 is as follows:

[0032] Aerobic enhanced bacteria and water are mixed in a mass ratio of 5-6:10-15 and then allowed to stand for 3-5 days to obtain mixed bacterial agent 2, and then 10wt%-15wt% of mixed bacterial agent 2 is added to the primary bacterial hydrolysis waste liquid, and the secondary bacterial hydrolysis waste liquid is obtained after reacting for 2-5 days.

[0033] Preferably, the process of the agent 3 cooperating with hydrogen peroxide treatment in step S5 is as follows:

[0034] Aluminum, titanium, ferrous sulfate and modified activated carbon are mixed to obtain agent 3, and then 0.3wt%-0.5wt% of agent 3 and 0.2wt%-0.3wt% of hydrogen peroxide are added to the secondary bacterial hydrolysis waste liquid, and the oxidized waste liquid is obtained after reacting for 5-7 hours.

[0035] Preferably, the mass ratio of the aluminum, titanium, ferrous sulfate and modified activated carbon is 3-3.5:2-3:3-3.5:2-2.5:0.3.

[0036] Preferably, the treatment process of the medicine 4 in step S6 is as follows:

[0037] Water, polyaluminium chloride and polyacrylamide are mixed to obtain agent 4, and then 0.02wt%-0.03wt% of agent 4 is added to the oxidation waste liquid, and the pH is adjusted to 6.5-8.5 after reacting for 1-3h, and then filtered to obtain the treated vacuum waste liquid.

[0038] Preferably, the mass ratio of water, polyaluminium chloride and polyacrylamide is 80-90:10-12:2-2.2;

[0039] The pore size of the filter membrane during the filtration process is 2-8 nm.

[0040] Beneficial effects of the present invention:

[0041] The present invention provides a highly efficient treatment method for vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coatings. The treatment method of the present invention comprises the following steps: firstly removing the floating oil and then sieving the waste liquid, then treating the waste liquid with a mixture of calcium hydroxide, polyaluminium chloride and polyacrylamide, and then scraping off the scum to obtain a defloating waste liquid with a low acetaldehyde content; treating the defloating waste liquid with a mixture of iron powder and modified activated carbon to obtain a reduced waste liquid with a low heavy metal ion content; treating the reduced waste liquid with a mixed bacterial agent 1 after adjusting the pH value and temperature, and then treating the waste liquid with a mixed bacterial agent 2 to obtain a secondary bacterial decomposition waste liquid; treating the secondary bacterial decomposition waste liquid with a medicament 3 in coordination with hydrogen peroxide, and then treating the waste liquid with a medicament 4 to obtain a treated vacuum waste liquid with ammonia nitrogen and other contents lower than the emission standard. Therefore, compared with the prior art, the treatment method of the present invention has high efficiency, good effect and broad application prospects. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0043] The sources and properties of some of the raw materials used in the present invention are as follows:

[0044] Anaerobic enhancing bacteria were purchased from Shandong Xiaohainiu Environmental Protection Materials Co., Ltd.; anaerobic granular sludge was purchased from Shandong Xiaohainiu Environmental Protection Materials Co., Ltd.; aerobic enhancing bacteria were purchased from Shandong Xiaohainiu Environmental Protection Materials Co., Ltd.

[0045] Example 1: An efficient method for treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating is as follows:

[0046] S1: Reagent A obtained by mixing calcium hydroxide, polyaluminium chloride, polyacrylamide and water in a mass ratio of 7:5:2:70;

[0047] S2: After removing the floating oil from the vacuum waste liquid, the waste liquid is sieved with a sieve with a pore size of 0.06 mm, and then 0.03 wt% of reagent 1 is added and stirred until the pH of the waste liquid reaches 1.9, and then the floating scum is scraped off to obtain the defloated waste liquid;

[0048] S3: 90g of 0.1mol / L potassium permanganate solution was heated to 55°C, 15g of activated carbon was added, and the mixture was subjected to ultrasonic oscillation at 55°C for 1h. After washing, the mixture was dried at 75°C, and then calcined at 300°C for 4h to obtain modified activated carbon. The ultrasonic power during the ultrasonic oscillation was 60W, and the ultrasonic frequency during the ultrasonic oscillation was 40kHz.

[0049] S4: Mixing iron powder and modified activated carbon in a mass ratio of 7:2 to obtain reagent 2, then adding 30 wt % of reagent 2 to the deflocculated waste liquid, stirring and reacting for 2 h to obtain a reduced waste liquid;

[0050] S5: the anaerobic enhanced bacteria and water are mixed and allowed to stand for 2 days, and then anaerobic granular sludge, urea and sodium phosphate are added to obtain a mixed bacterial agent 1, and then 8.4wt% of the mixed bacterial agent 1 is added to the reduced waste liquid with the pH adjusted to 6.5 and the temperature adjusted to 25°C and allowed to stand for 1.5 days to obtain a primary bacterial hydrolysis waste liquid; the mass ratio of the anaerobic enhanced bacteria, water, anaerobic granular sludge, urea and sodium phosphate is 5:10:0.3:5.4:4.5;

[0051] S6: aerobic enhanced bacteria and water are mixed at a mass ratio of 5:10 and then allowed to stand for 3 days to obtain mixed bacterial agent 2, and then 10 wt% of mixed bacterial agent 2 is added to the primary bacterial hydrolysis waste liquid, and the secondary bacterial hydrolysis waste liquid is obtained after reacting for 2 days;

[0052] S7: Aluminum, titanium, ferrous sulfate, and modified activated carbon in a mass ratio of 3:2:3:2:0.3 are mixed to obtain agent 3, and then 0.3wt% of agent 3 and 0.2wt% of hydrogen peroxide are added to the secondary bacterial hydrolysis waste liquid, and the oxidized waste liquid is obtained after reacting for 5 hours;

[0053] S8: mixing water, polyaluminium chloride and polyacrylamide in a mass ratio of 80:10:2 to obtain agent 4, then adding 0.02wt% of agent 4 to the oxidation waste liquid, adjusting the pH to 6.5 after reacting for 1h, and then filtering through a filter membrane with a pore size of 2nm to obtain a treated vacuum waste liquid;

[0054] Example 2: An efficient method for treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating is as follows:

[0055] S1: Reagent A obtained by mixing calcium hydroxide, polyaluminium chloride, polyacrylamide and water in a mass ratio of 8:5.1:2:80;

[0056] S2: After removing the floating oil from the vacuum waste liquid, the waste liquid is sieved with a sieve with a pore size of 0.07 mm, and then 0.034 wt% of reagent 1 is added and stirred until the pH value of the waste liquid reaches 2, and then the floating scum is scraped off to obtain the defloated waste liquid;

[0057] S3: 93g of 0.12mol / L potassium permanganate solution was heated to 57°C, 17g of activated carbon was added, and ultrasonic oscillation was performed at 57°C for 1.2h, and then the solution was dried at 77°C after washing, and then calcined at 350°C for 4.5h to obtain modified activated carbon; the ultrasonic power during the ultrasonic oscillation was 65W, and the ultrasonic frequency during the ultrasonic oscillation was 42kHz;

[0058] S4: Mixing iron powder and modified activated carbon in a mass ratio of 8:2.5 to obtain reagent 2, then adding 34 wt % of reagent 2 to the deflocculated waste liquid, stirring and reacting for 2.3 h to obtain a reduced waste liquid;

[0059] S5: mixing the anaerobic enhanced bacteria and water and letting it stand for 3 days, then adding anaerobic granular sludge, urea and sodium phosphate to obtain mixed bacterial agent 1, then adding 9wt% mixed bacterial agent 1 to the reduced waste liquid with the pH adjusted to 6.7 and the temperature adjusted to 29°C and leaving it for 2 days to obtain a primary bacterial hydrolysis waste liquid; the mass ratio of the anaerobic enhanced bacteria, water, anaerobic granular sludge, urea and sodium phosphate is 6:12:0.4:5.6:4.7;

[0060] S6: aerobic enhanced bacteria and water are mixed at a mass ratio of 5.4:12 and then allowed to stand for 3.5 days to obtain mixed bacterial agent 2, and then 12 wt% of mixed bacterial agent 2 is added to the primary bacterial hydrolysis waste liquid, and the secondary bacterial hydrolysis waste liquid is obtained after reacting for 3 days;

[0061] S7: Aluminum, titanium, ferrous sulfate, and modified activated carbon in a mass ratio of 3.2:2.3:3.2:2.2:0.3 are mixed to obtain agent 3, and then 0.4wt% of agent 3 and 0.25wt% of hydrogen peroxide are added to the secondary bacterial hydrolysis waste liquid, and the oxidized waste liquid is obtained after reacting for 5.5h;

[0062] S8: mixing water, polyaluminium chloride and polyacrylamide in a mass ratio of 83:10.5:2.1 to obtain agent 4, then adding 0.023wt% of agent 4 to the oxidation waste liquid, adjusting the pH to 7 after reacting for 1.5h, and then filtering through a filter membrane with a pore size of 4nm to obtain a treated vacuum waste liquid;

[0063] Example 3: An efficient method for treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating is as follows:

[0064] S1: Reagent A obtained by mixing calcium hydroxide, polyaluminium chloride, polyacrylamide and water in a mass ratio of 9:5.4:2:90;

[0065] S2: After removing the floating oil from the vacuum waste liquid, the waste liquid is sieved with a sieve with a pore size of 0.08 mm, and then 0.037 wt% of reagent 1 is added and stirred until the pH value of the waste liquid reaches 2, and then the floating scum is scraped off to obtain the defloated waste liquid;

[0066] S3: 98g of 0.13mol / L potassium permanganate solution was heated to 58°C, 18g of activated carbon was added, and ultrasonic oscillation was performed at 58°C for 1.7h, and then the mixture was dried at 78°C after washing, and then calcined at 420°C for 4.8h to obtain modified activated carbon; the ultrasonic power during the ultrasonic oscillation was 67W, and the ultrasonic frequency during the ultrasonic oscillation was 43kHz;

[0067] S4: Mixing iron powder and modified activated carbon in a mass ratio of 9:3.5 to obtain reagent 2, then adding 39 wt % of reagent 2 to the deflocculated waste liquid, stirring and reacting for 2.7 h to obtain a reduced waste liquid;

[0068] S5: mixing the anaerobic enhanced bacteria and water and letting it stand for 4 days, then adding anaerobic granular sludge, urea and sodium phosphate to obtain mixed bacterial agent 1, then adding 9.5wt% mixed bacterial agent 1 to the reduced waste liquid with the pH adjusted to 6.8 and the temperature adjusted to 31°C and leaving it for 2.5 days to obtain a primary bacterial hydrolysis waste liquid; the mass ratio of the anaerobic enhanced bacteria, water, anaerobic granular sludge, urea and sodium phosphate is 6.5:14:0.4:5.8:4.8;

[0069] S6: aerobic enhanced bacteria and water are mixed at a mass ratio of 5.8:13 and then allowed to stand for 4.5 days to obtain mixed bacterial agent 2, and then 13 wt% of mixed bacterial agent 2 is added to the primary bacterial hydrolysis waste liquid, and the secondary bacterial hydrolysis waste liquid is obtained after reacting for 4 days;

[0070] S7: Aluminum, titanium, ferrous sulfate, and modified activated carbon in a mass ratio of 3.4:2.8:3.4:2.4:0.3 are mixed to obtain agent 3, and then 0.45wt% of agent 3 and 0.28wt% of hydrogen peroxide are added to the secondary bacterial hydrolysis waste liquid, and the oxidized waste liquid is obtained after reacting for 6.5h;

[0071] S8: mixing water, polyaluminium chloride and polyacrylamide in a mass ratio of 88:11.5:2.1 to obtain agent 4, then adding 0.028wt% of agent 4 to the oxidation waste liquid, adjusting the pH to 7.5 after reacting for 2.5h, and then filtering through a filter membrane with a pore size of 6nm to obtain a treated vacuum waste liquid;

[0072] Example 4: An efficient method for treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating is as follows:

[0073] S1: Reagent A obtained by mixing calcium hydroxide, polyaluminium chloride, polyacrylamide and water in a mass ratio of 10:5.5:2:100;

[0074] S2: After removing the floating oil from the vacuum waste liquid, the waste liquid is sieved with a sieve with a pore size of 0.1 mm, and then 0.04 wt% of reagent 1 is added and stirred until the pH of the waste liquid reaches 2.1, and then the floating scum is scraped off to obtain the deflocculated waste liquid;

[0075] S3: 100 g of a 0.15 mol / L potassium permanganate solution was heated to 60°C, 20 g of activated carbon was added, and the mixture was subjected to ultrasonic oscillation at 60°C for 2 h. After washing, the mixture was dried at 80°C, and then calcined at 500°C for 5 h to obtain modified activated carbon. The ultrasonic power during the ultrasonic oscillation was 70 W, and the ultrasonic frequency during the ultrasonic oscillation was 45 kHz.

[0076] S4: Mixing iron powder and modified activated carbon in a mass ratio of 10:4 to obtain reagent 2, then adding 40wt% of reagent 2 to the deflocculated waste liquid, stirring and reacting for 3h to obtain a reduced waste liquid;

[0077] S5: mixing the anaerobic enhanced bacteria and water and letting it stand for 5 days, then adding anaerobic granular sludge, urea and sodium phosphate to obtain mixed bacterial agent 1, then adding 10wt% of mixed bacterial agent 1 to the reduced waste liquid with the pH adjusted to 7.0 and the temperature adjusted to 35°C and leaving it for 3 days to obtain a primary bacterial hydrolysis waste liquid; the mass ratio of the anaerobic enhanced bacteria, water, anaerobic granular sludge, urea and sodium phosphate is 7:15:0.5:6:5;

[0078] S6: aerobic enhanced bacteria and water are mixed at a mass ratio of 6:15 and then allowed to stand for 5 days to obtain mixed bacterial agent 2, and then 15 wt% of mixed bacterial agent 2 is added to the primary bacterial hydrolysis waste liquid, and the secondary bacterial hydrolysis waste liquid is obtained after reacting for 5 days;

[0079] S7: Aluminum, titanium, ferrous sulfate, and modified activated carbon in a mass ratio of 3.5:3:3.5:2.5:0.3 are mixed to obtain agent 3, and then 0.5wt% of agent 3 and 0.3wt% of hydrogen peroxide are added to the secondary bacterial hydrolysis waste liquid, and the oxidized waste liquid is obtained after reacting for 7 hours;

[0080] S8: mixing water, polyaluminium chloride and polyacrylamide in a mass ratio of 90:12:2.2 to obtain agent 4, then adding 0.03wt% of agent 4 to the oxidation waste liquid, adjusting the pH to 8.5 after reacting for 3h, and then filtering through a filter membrane with a pore size of 8nm to obtain a treated vacuum waste liquid;

[0081] Comparative Example 1:

[0082] Compared with Example 1, this comparative example does not add calcium hydroxide during the preparation of reagent 1. The remaining steps and parameters are the same, and this comparative example will not be repeated. Finally, the treated vacuum waste liquid is obtained;

[0083] Comparative Example 2:

[0084] Compared with Example 1, this comparative example only replaces the "agent 1" used in the preparation process of the deflocculated waste liquid with "deionized water", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally the treated vacuum waste liquid is obtained;

[0085] Comparative Example 3:

[0086] Compared with Example 1, this comparative example only replaces the "modified activated carbon" used in the preparation process of Agent 2 with "activated carbon", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally the treated vacuum waste liquid is obtained;

[0087] Comparative Example 4:

[0088] Compared with Example 1, this comparative example does not add urea and sodium phosphate during the preparation of the mixed bacterial agent 1. The remaining steps and parameters are the same, and this comparative example will not be repeated. Finally, the treated vacuum waste liquid is obtained;

[0089] Comparative Example 5:

[0090] Compared with Example 1, this comparative example does not add modified activated carbon during the preparation of Agent 3. The remaining steps and parameters are the same and will not be repeated in this comparative example. Finally, treated vacuum waste liquid is obtained.

[0091] Performance Test:

[0092] Determination of chemical oxygen demand COD:

[0093] Refer to the test standard HJ828-2017 "Water Quality, Determination of Chemical Oxygen Demand, Dichromate Method", take 3 groups of treated vacuum waste liquid as water samples, take 10ml of water sample in a conical flask, add 0.5g of mercuric sulfate and 5ml of sulfuric acid mixed solution, 5ml of 0.025mol / L potassium dichromate standard solution and 3 explosion-proof boiling glass beads in turn, and shake well. Connect the conical flask to the lower end of the reflux device condenser, slowly add a mixture of 0.15g of silver sulfate and 15ml of sulfuric acid solution from the upper end of the condenser, and keep the solution boiling for 2h. After reflux and cooling, add 45ml of water from the upper end of the condenser to rinse the condenser, and remove the conical flask. After the solution is cooled to room temperature, add 3 drops of ferrous iron indicator solution, and titrate with 0.005mol / L ammonium ferrous sulfate standard solution. The color of the solution changes from yellow to blue-green to reddish brown, which is the end point. Record the consumption volume V1 of the ammonium ferrous sulfate standard solution. The blank test was performed by replacing the water sample with water, and the volume V0 of the ammonium ferrous sulfate standard solution consumed during the blank titration was recorded; the vacuum waste liquids treated in Examples 1 to 4 and Comparative Examples 1 to 5 were measured in this way, and the chemical oxygen demand of each water sample was calculated according to the following formula 1, and the average value of each group was taken as the chemical oxygen demand (mg·L -1 );

[0094] Formula 1:

[0095] Determination of ammonia nitrogen concentration:

[0096] Refer to the test standard HJ537-2009 "Water quality, determination of ammonia nitrogen, distillation-neutralization titration", take 3 groups of treated vacuum waste liquid as water samples, transfer the boric acid absorption solution made of 1g boric acid and 50ml water into the receiving bottle; take 250ml water sample and transfer it into the flask, add 2 drops of bromothymol blue indicator and 0.25g magnesium oxide and 3 glass beads, immediately connect the nitrogen ball and condenser to heat and distill, so that the distillate rate is about 10ml / min, and stop distillation when the distillate reaches 200ml. Transfer all the distillate to a conical flask, add 2 drops of mixed indicator made of 200mg methyl red and 100ml ethanol, 50mg methylene blue and 50ml ethanol mixed and stabilized for 1 month, and titrate with 0.02mol / L hydrochloric acid solution until the distillate changes from green to lavender as the end point, and record the volume V1 of the consumed hydrochloric acid standard titration solution. 250 ml of distilled water was used to replace the water sample, and the titration was performed in the same manner, and the volume V2 of the consumed hydrochloric acid standard titration solution was recorded; the vacuum waste liquids treated in Examples 1 to 4 and Comparative Examples 1 to 5 were measured in this manner, and the ammonia nitrogen concentration of each water sample was calculated according to Formula 2 below, and the average value of each group was taken as the ammonia nitrogen concentration (mg·L -1 );

[0097] Formula 2:

[0098] Determination of colony count:

[0099] Refer to the determination standard HJ1000-2018 "Water quality, determination of total bacteria count, plate counting method", take 3 groups of treated vacuum waste liquid as water samples, shake the samples vigorously for 20-25 times to disperse possible bacterial agglomerates. Aseptically aspirate 10ml of sample, inject into a conical flask containing 90ml sterile water, and mix into a 1:10 diluted sample. Aspirate 10ml of the 1:10 diluted sample and inject into a conical flask containing 90ml sterile water, and mix into a 1:100 diluted sample. Dilute to a 1:1000 diluted sample in the same way. Use a sterile pipette to aspirate 1ml of the fully mixed sample or diluted sample, inject it into a sterile plate, pour 20ml of nutrient agar medium cooled to 45°C, and immediately vortex the plate to fully mix the sample or diluted sample with the medium. Pour 2 plates for each sample or diluted sample. After the nutrient agar medium in the plate is cooled and solidified, the plate is turned over so that the bottom is facing up, and the results are observed after incubation at 35° C. for 48 hours, and the corresponding colony counts are recorded and calculated; wherein the colony count is the average value of the total number of colonies in each plate multiplied by the dilution multiple; sterile water is used for laboratory blank determination at the same time; the vacuum waste liquid treated by Example 1 to Example 4 and Comparative Example 1 to Comparative Example 5 is measured for colony count according to this method; the measurement results are shown in Table 1;

[0100] Table 1

[0101]

[0102]

[0103] Data Analysis:

[0104] It can be seen from the embodiments of the present invention and Table 1 that the vacuum waste liquid treatment method of the present invention has better chemical oxygen demand, ammonia nitrogen content, colony count reduction ability and faster treatment speed, that is, the present invention has higher waste liquid treatment efficiency and better treatment effect;

[0105] This may be because the present invention first uses calcium hydroxide, polyaluminium chloride, and polyacrylamide mixed reagent 1 to treat vacuum waste liquid, thereby reducing the acetaldehyde content in the waste liquid, thereby reducing the negative impact of acetaldehyde on subsequent bacterial agent treatment; then the activated carbon is modified to improve the adsorption and catalytic capacity of the activated carbon, thereby reducing the heavy metal ion content in the waste liquid, thereby further reducing the negative impact of the waste liquid on subsequent bacterial agent treatment; after adjusting the pH value and temperature of the reduced waste liquid, the present invention uses anaerobic enhanced bacteria, anaerobic granular sludge, urea and sodium phosphate to prepare a mixed bacterial agent treatment 1 to treat the waste liquid, wherein the addition of urea and sodium phosphate can provide a necessary living environment for microorganisms, so that the concentration of pollutants in the wastewater can be reduced to the maximum extent in a short time; and the addition of modified activated carbon in reagent 3 can further reduce the content of ammonia nitrogen, heavy metals, etc. in the waste liquid. Combined with the simple and easy-to-operate vacuum waste liquid treatment method of the present invention, the treatment method of the present invention is not only efficient, but also effective.

[0106] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0107] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A highly efficient method for treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating, characterized in that: The following steps are involved: Step S1: After removing the floating oil in the vacuum waste liquid, the waste liquid is sieved, then treated with reagent 1, and then the floating scum is scraped off to obtain the de-floating waste liquid; Step S2: treating the deflocculated waste liquid with reagent 2 to obtain reduced waste liquid; Step S3: adjusting the pH of the reduced waste liquid to 6.5-7.0 and the temperature to 25-35° C., and then treating it with the mixed bacterial agent 1 to obtain a primary bacterial hydrolysis waste liquid; Step S4: treating the primary bacterial hydrolysis waste liquid with mixed bacterial agent 2 to obtain secondary bacterial hydrolysis waste liquid; Step S5: treating the secondary bacterial hydrolysis waste liquid with reagent 3 in combination with hydrogen peroxide to obtain oxidized waste liquid; Step S6: treating the oxidation waste liquid with reagent 4 to obtain treated vacuum waste liquid; The agent 1 is obtained by mixing calcium hydroxide, polyaluminium chloride and polyacrylamide; The reagent 2 is obtained by mixing iron powder and modified activated carbon; The mixed bacterial agent 1 is prepared by mixing anaerobic enhanced bacteria, anaerobic granular sludge, urea, and sodium phosphate; the agent 3 is prepared by mixing aluminum, titanium, ferrous sulfate, and modified activated carbon; The agent 4 is obtained by mixing polyaluminium chloride and polyacrylamide.

2. The method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating according to claim 1, characterized in that: The aperture size of the sieve during the screening process in step S1 is 0.06-0.1 mm.

3. The method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating according to claim 1, characterized in that: The treatment process of the medicine 1 in step S1 is as follows: Calcium hydroxide, polyaluminium chloride, polyacrylamide and water are mixed in a mass ratio of 7-10:5-5.5:2:70-100 to obtain agent A, and then 0.03wt%-0.04wt% of agent 1 is added to the sieved waste liquid, and then stirred until the pH of the waste liquid reaches 1.9-2.

1.

4. The method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating according to claim 1, characterized in that: The treatment process of the medicine 2 in step S2 is as follows: Step B1: heating 90-100 g of 0.1-0.15 mol / L potassium permanganate solution to 55-60° C., adding 15-20 g of activated carbon, reacting with ultrasonic vibration at 55-60° C. for 1-2 h, washing, drying at 75-80° C., and calcining at 300-500° C. for 4-5 h to obtain modified activated carbon; The ultrasonic power during the ultrasonic oscillation is 60-70W, and the ultrasonic frequency during the ultrasonic oscillation is 40-45kHz; Step B2: Mix iron powder and modified activated carbon in a mass ratio of 7-10:2-4 to obtain reagent 2, then add 30wt%-40wt% of reagent 2 to the deflocculated waste liquid, stir and react for 2-3h to obtain reduced waste liquid.

5. The method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating according to claim 1, characterized in that: The treatment process of the mixed bacterial agent 1 in step S3 is as follows: The anaerobic enhanced bacteria and water are mixed and then allowed to stand for 2-5 days, and then anaerobic granular sludge, urea and sodium phosphate are added to obtain a mixed bacterial agent 1, and then 8.4wt%-10wt% of the mixed bacterial agent 1 is added to the reduced waste liquid and allowed to stand for 1.5-3 days to obtain a primary bacterial hydrolysis waste liquid; The mass ratio of the anaerobic strengthening bacteria, water, anaerobic granular sludge, urea and sodium phosphate is 5-7:10-15:0.3-0.5:5.4-6:4.5-5.

6. The method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating according to claim 1, characterized in that: The mixed bacterial agent 2 treatment process in step S4 is as follows: Aerobic enhanced bacteria and water are mixed in a mass ratio of 5-6:10-15 and then allowed to stand for 3-5 days to obtain mixed bacterial agent 2, and then 10wt%-15wt% of mixed bacterial agent 2 is added to the primary bacterial hydrolysis waste liquid, and the secondary bacterial hydrolysis waste liquid is obtained after reacting for 2-5 days.

7. The method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating according to claim 1, characterized in that: The process of treating with the reagent 3 in step S5 in cooperation with hydrogen peroxide is as follows: Aluminum, titanium, ferrous sulfate and modified activated carbon are mixed to obtain agent 3, and then 0.3wt%-0.5wt% of agent 3 and 0.2wt%-0.3wt% of hydrogen peroxide are added to the secondary bacterial hydrolysis waste liquid, and the oxidized waste liquid is obtained after reacting for 5-7 hours.

8. The method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating according to claim 7, characterized in that: The mass ratio of the aluminum, titanium, ferrous sulfate and modified activated carbon is 3-3.5:2-3:3-3.5:2-2.5:0.

3.

9. The method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating according to claim 1, characterized in that: The treatment process of the medicine 4 in step S6 is as follows: Water, polyaluminium chloride and polyacrylamide are mixed to obtain agent 4, and then 0.02wt%-0.03wt% of agent 4 is added to the oxidation waste liquid, and the pH is adjusted to 6.5-8.5 after reacting for 1-3h, and then filtered to obtain the treated vacuum waste liquid.

10. The method for efficiently treating vacuum waste liquid generated in the synthesis reaction of polyester resin for powder coating according to claim 9, characterized in that: The mass ratio of water, polyaluminium chloride and polyacrylamide is 80-90:10-12:2-2.2; During the filtration process, the pore size of the filter membrane is 2-8 nm.

Images