Emulsion wastewater resource utilization and environment-friendly treatment method

Abstract

The invention relates to an emulsion wastewater resource utilization and environment-friendly treatment method, which can effectively solve the problem that a single treatment method is difficult to obtain a better treatment effect at a lower cost, and the technical scheme for solving the problem is as follows: the method comprises the following steps: S1, collecting emulsion wastewater in an adjusting tank and lifting to an oil separation sedimentation tank; s2, enabling the wastewater subjected to oil separation treatment of the oil separation sedimentation tank to overflow into a high-efficiency air floatation tank; s3, pumping air floatation effluent into an evaporation reactor; s4, pumping the evaporated condensate into an HA-TJ biochemical system; s5, enabling effluent of the aerobic tank to enter an MBR membrane tank; s6, carrying out dehydration treatment on residual sludge and residues; s7, collecting odor of a workshop system through an induced draft fan and an air pipe according to flying dust generated in the whole technological process; according to the method, oil and water in the waste emulsion can be separated, byproducts are extracted from the waste oil, the recycling effect is achieved, the separated waste water can be further subjected to deep treatment to achieve up-to-standard discharge, and the method is an innovation in waste water treatment methods.

Description

Technical Field

[0001] The invention relates to the field of wastewater treatment, in particular to a method for resource utilization and environmental protection treatment of emulsion wastewater. Background Art

[0002] As a high-performance semi-synthetic metalworking fluid, emulsion is mainly used as a cooling lubricant (with good cooling, lubrication, rust prevention and cleaning functions) in the mechanical processing and manufacturing process. Emulsion needs to be replaced regularly, and expired emulsion needs to be discharged to the outside, forming emulsion wastewater. The organic matter concentration of emulsion wastewater can be as high as tens of thousands to hundreds of thousands, which is difficult to biodegrade. Direct discharge will have a serious impact on the environment and has been included in the national hazardous waste list (HW09).

[0003] At present, the treatment methods for emulsion wastewater mainly include biological method, physical method, chemical method, etc. Since emulsion wastewater generally has low biodegradability, biological method is generally not directly used to treat emulsion wastewater at home and abroad. Physical methods include gravity separation, coarse granulation, membrane separation, centrifugation, etc. Such treatment methods often have high operating and management costs, and high initial equipment investment, which limits the scope of use. Chemical treatment methods mainly include chemical oxidation, salting out, acidification, coagulation, mixing, electrochemical method, etc. The cost of adding reagents for such treatment methods is high, and the oily sludge produced by some treatment methods is difficult to treat.

[0004] For example: Chinese patent application number: 202110854183.3 discloses a treatment process for wastewater containing emulsion, which is to first break the emulsion to separate oil and water, then remove impurities through a ceramic membrane filter, and then enter the subsequent main biochemical process, including "pre-oxidation-anaerobic-anoxic-contact oxidation-secondary sedimentation tank", etc. Although this process has a large processing capacity, low cost, and low operating requirements, the emulsion wastewater generally has a high COD, poor biodegradability, and even contains some toxic substances. Therefore, the process is not very applicable, the effluent water quality is not high, and it is difficult to meet the emission standards required by the enterprise.

[0005] Chinese patent application number: 202010391235.3 discloses a method for treating ultra-low emissions of emulsion wastewater in the manufacturing industry. The entire process adopts a combined process of "demulsification-ceramic membrane filtration-ozone catalytic oxidation-multi-stage AO-MBR-ion exchange adsorption". On the basis of the biochemical process, the ozone catalytic oxidation process is added in the front and the ion exchange adsorption process is added in the back. Ozone catalytic oxidation can degrade and partially inorganicize the difficult-to-degrade organic matter in the water, thereby improving the biodegradability of the wastewater. Ion exchange adsorption can remove excessive nitrate ions in the effluent, thereby ensuring that the final effluent COD, N and P can meet the emission standards. The shortcomings of this process are that the ozone oxidation capacity is limited, the catalyst life is also short, the activity is not guaranteed, and the catalyst is prone to hardening for a long time, or even poisoning and inactivation, which greatly reduces the effect of water treatment and has high replacement costs. Therefore, the improvement and innovation of the emulsion wastewater treatment method is an urgent problem to be solved. Summary of the invention

[0006] In view of the above situation, in order to solve the defects of the prior art, the purpose of the present invention is to provide a method for resource utilization and environmental protection of emulsion wastewater, which can effectively solve the problem that a single treatment method is difficult to achieve better treatment effects at a lower cost.

[0007] The technical solution provided by the present invention is that the method for resource utilization and environmental protection treatment of emulsion wastewater comprises the following steps: S1. The emulsion wastewater collected in the regulating tank is lifted to the oil separation sedimentation tank by the lifting pump. The floating oil is collected and enters the oil recovery system. The precipitated oil residue and other impurities accumulate in the sludge hopper at the bottom of the sludge disposal system and enter the sludge pipe through the sludge discharge pipe; S2. The wastewater treated by oil separation in the oil separation sedimentation tank overflows into the high-efficiency flotation tank, where flocculants PAC and PAM are added to further remove suspended solids and a small amount of residual floating oil in the emulsion wastewater; S3, pump the flotation water into the evaporation reactor, control the evaporation temperature, the evaporator condensate is mainly water vapor and a small amount of light components, enters the HA-TJ biochemical system for biochemical treatment, the evaporated waste liquid enters the oil recovery system, controls the device temperature, adds acid to adjust the pH, fully stirs and stands, the upper clear oil after acid separation and demulsification is recycled and purified for resource utilization, and the lower concentrated liquid is discharged into the sludge pipe; S4, the evaporation condensate is pumped into the HA-TJ biochemical system, and passes through the anoxic tank and aerobic tank of the HA-TJ biochemical system in turn to control the dissolved oxygen concentration and HRT residence time. Under the action of special bacteria, the organic matter is decomposed into N2, CO2 and H2O; S5. The effluent from the aerobic pool enters the MBR membrane pool. The sludge concentration in the membrane pool is higher, the microbial activity in the sludge is also relatively high, and the impact resistance is relatively strong, which further degrades the organic matter in the wastewater and ensures the stable operation of the entire system. The sludge water enters the clean water tank after membrane separation. The effluent water quality is relatively good and can be fully reused for production; The excess sludge from the S6 and HA-TJ biochemical systems, the residue from the sludge pipes and the oil recovery system are dehydrated, and the dehydrated sludge is then dried with waste heat to reduce the sludge volume. The dried sludge is then outsourced for disposal; S7. The flying dust generated during the whole process is collected by the induced draft fan and the air duct to collect the odor of the workshop system, and enters the exhaust gas treatment system after removing the water mist, meeting the national standard "Comprehensive Emission Standard of Air Pollutants" (GB16297-1996) and the "Emission Standard of Odor Pollutants" GB 14554-1993 Table 1 Secondary Standard. The exhaust gas that meets the standard is discharged in an organized manner through the exhaust pipe, with a height of not less than 15 meters.

[0008] The treatment method of the present invention can not only separate the oil and water in the waste emulsion and extract by-products from the waste oil to achieve the effect of resource utilization, but also further deeply treat the separated wastewater to achieve standard discharge, thereby meeting the requirements of increasingly stringent environmental emission standards; at the same time, it takes into account investment conditions, the impact of odor and noise on the surrounding environment and the convenience of subsequent operation and maintenance, etc., and is an innovation in wastewater treatment methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a process flow chart of the present invention.

[0010] Figure 2 It is a structural connection frame diagram of the wastewater treatment device of the present invention. DETAILED DESCRIPTION

[0011] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings. Example 1

[0012] In the specific implementation of the present invention, the emulsion wastewater resource utilization and environmental protection treatment method utilizes a wastewater treatment device and then treats it according to the following steps: S1. The emulsion wastewater collected in the regulating tank is lifted to the oil separation sedimentation tank by the lifting pump. The floating oil is collected and enters the oil recovery system. The precipitated oil residue and other impurities accumulate in the sludge hopper at the bottom of the sludge disposal system and enter the sludge pipe through the sludge discharge pipe; S2. The wastewater treated by oil separation in the oil separation sedimentation tank overflows into the high-efficiency flotation tank, where flocculants PAC and PAM are added to further remove suspended solids and a small amount of residual floating oil in the emulsion wastewater; S3, pump the flotation water into the evaporation reactor, control the evaporation temperature, the evaporator condensate is mainly water vapor and a small amount of light components, enters the HA-TJ biochemical system for biochemical treatment, the evaporated waste liquid enters the oil recovery system, controls the device temperature, adds acid to adjust the pH, fully stirs and stands, the upper clear oil after acid separation and demulsification is recycled and purified for resource utilization, and the lower concentrated liquid is discharged into the sludge pipe; S4, the evaporation condensate is pumped into the HA-TJ biochemical system, and passes through the anoxic tank and aerobic tank of the HA-TJ biochemical system in turn to control the dissolved oxygen concentration and HRT residence time. Under the action of special bacteria, the organic matter is decomposed into N2, CO2 and H2O; S5. The effluent from the aerobic pool enters the MBR membrane pool. The sludge concentration in the membrane pool is higher, the microbial activity in the sludge is also relatively high, and the impact resistance is relatively strong, which further degrades the organic matter in the wastewater and ensures the stable operation of the entire system. The sludge water enters the clean water tank after membrane separation. The effluent water quality is relatively good and can be fully reused for production; The excess sludge from the S6 and HA-TJ biochemical systems, the residue from the sludge pipes and the oil recovery system are dehydrated, and the dehydrated sludge is then dried with waste heat to reduce the sludge volume. The dried sludge is then outsourced for disposal; S7. The flying dust generated during the whole process is collected by the induced draft fan and the air duct to collect the odor of the workshop system, and enters the exhaust gas treatment system after removing the water mist, meeting the national standard "Comprehensive Emission Standard of Air Pollutants" (GB16297-1996) and the "Emission Standard of Odor Pollutants" GB 14554-1993 Table 1 Secondary Standard. The exhaust gas that meets the standard is discharged in an organized manner through the exhaust pipe, with a height of not less than 15 meters.

[0013] In order to ensure the use effect, the wastewater treatment device includes a regulating tank, an oil-water separation sedimentation tank, a high-efficiency air flotation tank, a sludge disposal system, a HA-TJ biochemical system, and an oil recovery system. The output end of the regulating tank is connected to the input end of the oil-water separation sedimentation tank through a lifting pump, the water outlet of the oil-water separation sedimentation tank is connected to the water inlet of the high-efficiency air flotation tank through a pipeline, the water outlet of the high-efficiency air flotation tank is connected to the water inlet of the evaporation reactor through a pipeline, the water outlet of the evaporation reactor is respectively connected to the water inlet of the HA-TJ biochemical system and the water inlet of the oil recovery system through a pipeline, the water outlet of the HA-TJ biochemical system is respectively connected to the water inlet of the sludge disposal system and the water inlet of the MBR membrane tank through a pipeline, the water outlet of the MBR membrane tank is respectively connected to the water inlet of the clean water tank and the water inlet of the sludge disposal system through a pipeline, and the water outlet of the oil recovery system is connected to the water inlet of the sludge disposal system through a pipeline.

[0014] The sludge disposal system is a HA404 spiral stack sludge dewatering machine.

[0015] The HA-TJ biochemical system is a traditional A / O biochemical pool.

[0016] The oil recovery system is a HA-100 oil-water separator.

[0017] The exhaust gas treatment system is a UV photolysis photocatalytic oxidizer.

[0018] In step S2, the concentrations of flocculants PAC and PAM are 10% and 1‰ respectively.

[0019] The evaporation temperature in step S3 is 150-200°C.

[0020] In step S3, the temperature of the oil recovery system is 55-70°C.

[0021] The acid solution in step S3 is concentrated nitric acid or concentrated sulfuric acid.

[0022] In step S3, the pH is 2-2.5.

[0023] The standing time in step S3 is 18-24 hours.

[0024] In step S4, the dissolved oxygen concentration is 0.3-0.5 mg / L in the anoxic tank and 3.0-3.5 mg / L in the aerobic tank; The HRT residence time in step S4 is 80 to 96 hours; In step S5, the sludge concentration in the membrane pool is 8000-12000 mg / L, and the residence time is 15-17 hours.

[0025] The evaporation reactor is a scraper evaporator.

[0026] The use of the present invention is that after field practice verification, a company engaged in aluminum processing and production produces 10 tons of waste emulsion every day. The waste emulsion is a high-concentration, high-COD, and difficult-to-degrade waste with an oil content of about 5%-10% and organic additives. The COD is about 80,000-130,000 mg / L.

[0027] The emulsified wastewater collected in the regulating tank is lifted to the oil separator sedimentation tank at a speed of 2m³ / h by a lifting pump. After standing for 40 minutes, the floating oil is collected and enters the oil recovery system. The precipitated heavy oil and other impurities accumulate in the sludge hopper at the bottom of the tank and enter the sludge pipe through the sludge discharge pipe.

[0028] The wastewater after oil separation treatment overflows into the high-efficiency flotation tank, where flocculants polyaluminium chloride (PAC) and polyacrylamide (PAM) are added. The dosage of polyaluminium chloride is 0.3g / L and the dosage of polyacrylamide is 0.8mg / L to further remove suspended matter and a small amount of residual floating oil in the emulsion wastewater. The effluent enters the evaporation reactor.

[0029] The evaporation temperature is controlled at 170℃. At this time, the condensate of the evaporator is mainly water vapor and a small amount of light components, and the COD is about 2000mg / L. The condensate then enters the HA-TJ biochemical system for biochemical treatment, passing through the anoxic section and the aerobic section in turn. Under the action of special bacteria, the organic matter is decomposed into N2, CO2 and H2O. Among them, the anoxic section is mechanically stirred, and the dissolved oxygen is less than 0.4mg / L; the aerobic section is aerated and stirred, and the dissolved oxygen is 1mg / L. The residence time of the biochemical section is a total of 90h, and the effluent COD is about 110mg / L.

[0030] The evaporated waste liquid enters the oil recovery system, where 6 ml / L nitric acid is added. After acid precipitation, the waste oil is recovered, purified and recycled. The effluent from the aerobic section enters the MBR membrane pool. The sludge concentration in the pool is 10,000 mg / L, the dissolved oxygen is greater than 2 mg / L, and the effluent COD is about 50 mg / L. This can not only separate the oil and water in the waste emulsion, but also further treat the separated wastewater to achieve standard discharge, meeting the requirements of increasingly stringent environmental emission standards. It is an innovation in the resource utilization of emulsion wastewater and environmental protection treatment methods, and has good economic and social benefits.

[0031] Compared with the prior art, the present invention has the following beneficial effects: 1) The present invention creatively introduces an evaporation process for treating emulsion wastewater. After the wastewater is evaporated and concentrated, the condensate has a low COD, which reduces the difficulty of subsequent biochemical treatment. The bottom waste liquid is also concentrated, and the demulsification effect is better after concentration, while minimizing the amount of demulsifier used.

[0032] 2) The present invention separates the oil and water in the waste emulsion, recovers the waste oil by graded manner, and extracts by-products to achieve the effect of resource utilization.

[0033] 3) The biochemical part of the present invention adopts HA-TJ biochemical system + MBR membrane treatment. The activity of special bacteria in the sludge is relatively high, and the impact resistance of the biochemical part is relatively large, which ensures the stable operation of the whole system. The muddy water is separated by the membrane, and the effluent water quality is relatively good, which can be fully reused for production.

[0034] 4) The present invention dehydrates the sludge generated in the process, and then uses waste heat to dry the dehydrated sludge, thereby achieving sludge reduction treatment; at the same time, the waste gas is collected, and after demisting, it enters the UV photolysis and photocatalytic oxidation purification equipment for deep treatment, and is discharged in an organized manner from the exhaust pipe after meeting the standards, truly achieving environmentally friendly closed-loop disposal.

[0035] It should be pointed out that the above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any technician familiar with the profession can make changes or modify the technical contents disclosed above into equivalent embodiments with equivalent changes without departing from the scope of the technical solution of the present invention, which all fall within the protection scope of the present invention.

Claims

1. A method for resource utilization and environmental protection of emulsion wastewater, characterized in that: The method for resource utilization and environmental protection treatment of emulsion wastewater utilizes a wastewater treatment device and then treats it according to the following steps: S1. The emulsion wastewater collected in the regulating tank is lifted to the oil separation sedimentation tank by the lifting pump. The floating oil is collected and enters the oil recovery system. The precipitated oil residue and other impurities accumulate in the sludge hopper at the bottom of the sludge disposal system and enter the sludge pipe through the sludge discharge pipe; S2. The wastewater treated by oil separation in the oil separation sedimentation tank overflows into the high-efficiency flotation tank, where flocculants PAC and PAM are added to further remove suspended solids and a small amount of residual floating oil in the emulsion wastewater; S3, pump the flotation water into the evaporation reactor, control the evaporation temperature, the evaporator condensate is mainly water vapor and a small amount of light components, enters the HA-TJ biochemical system for biochemical treatment, the evaporated waste liquid enters the oil recovery system, controls the device temperature, adds acid to adjust the pH, fully stirs and stands, the upper clear oil after acid separation and demulsification is recycled and purified for resource utilization, and the lower concentrated liquid is discharged into the sludge pipe; S4, the evaporation condensate is pumped into the HA-TJ biochemical system, and passes through the anoxic tank and aerobic tank of the HA-TJ biochemical system in turn to control the dissolved oxygen concentration and HRT residence time. Under the action of special bacteria, the organic matter is decomposed into N2, CO2 and H2O; S5. The effluent from the aerobic pool enters the MBR membrane pool. The sludge concentration in the membrane pool is higher, the microbial activity in the sludge is also relatively high, and the impact resistance is relatively strong, which further degrades the organic matter in the wastewater and ensures the stable operation of the entire system. The sludge water enters the clean water tank after membrane separation. The effluent water quality is relatively good and can be fully reused for production; The excess sludge from the S6 and HA-TJ biochemical systems, the residue from the sludge pipes and the oil recovery system are dehydrated, and the dehydrated sludge is then dried with waste heat to reduce the sludge volume. The dried sludge is then outsourced for disposal; S7. The flying dust generated during the whole process is collected by the induced draft fan and the air duct to collect the odor of the workshop system, and enters the exhaust gas treatment system after removing the water mist, meeting the national standard "Comprehensive Emission Standard of Air Pollutants" (GB16297-1996) and the "Emission Standard of Odor Pollutants" GB 14554-1993 Table 1 Secondary Standard. The exhaust gas that meets the standard is discharged in an organized manner through the exhaust pipe, with a height of not less than 15 meters.

2. The method for resource utilization and environmental protection treatment of emulsion wastewater according to claim 1, characterized in that: The wastewater treatment device comprises a regulating tank, an oil-separating sedimentation tank, a high-efficiency air flotation tank, a sludge disposal system, a HA-TJ biochemical system, and an oil recovery system. The output end of the regulating tank is connected to the input end of the oil-separating sedimentation tank via a lifting pump, the water outlet of the oil-separating sedimentation tank is connected to the water inlet of the high-efficiency air flotation tank via a pipeline, the water outlet of the high-efficiency air flotation tank is connected to the water inlet of the evaporation reactor via a pipeline, the water outlet of the evaporation reactor is respectively connected to the water inlet of the HA-TJ biochemical system and the water inlet of the oil recovery system via a pipeline, the water outlet of the HA-TJ biochemical system is respectively connected to the water inlet of the sludge disposal system and the water inlet of the MBR membrane tank via a pipeline, the water outlet of the MBR membrane tank is respectively connected to the water inlet of the clean water tank and the water inlet of the sludge disposal system via a pipeline, and the water outlet of the oil recovery system is connected to the water inlet of the sludge disposal system via a pipeline.

3. The method for resource utilization and environmental protection treatment of emulsion wastewater according to claim 1 or 2, characterized in that: The sludge disposal system is a HA404 spiral stack sludge dewatering machine.

4. The method for resource utilization and environmental protection treatment of emulsion wastewater according to claim 1 or 2, characterized in that: The HA-TJ biochemical system is a traditional A / O biochemical pool.

5. The method for resource utilization and environmental protection treatment of emulsion wastewater according to claim 1 or 2, characterized in that: The oil recovery system is a HA-100 oil-water separator.

6. The method for resource utilization and environmental protection treatment of emulsion wastewater according to claim 1, characterized in that: The exhaust gas treatment system is a UV photolysis photocatalytic oxidizer.

7. The method for resource utilization and environmental protection treatment of emulsion wastewater according to claim 1, characterized in that: In step S2, the concentrations of flocculants PAC and PAM are 10% and 1‰ respectively.

8. The method for resource utilization and environmental protection treatment of emulsion wastewater according to claim 1, characterized in that: In the step S3, the evaporation temperature is 150-200°C; the temperature of the oil recovery system is 55-70°C; the acid solution is concentrated nitric acid or concentrated sulfuric acid, the pH value is 2-2.5, and the standing time is 18-24h.

9. The method for resource utilization and environmental protection treatment of emulsion wastewater according to claim 1, characterized in that: In the step S4, the dissolved oxygen concentration is 0.3-0.5 mg / L in the anoxic tank and 3.0-3.5 mg / L in the aerobic tank; the HRT retention time is 80-96 h.

10. The method for resource utilization and environmental protection treatment of emulsion wastewater according to claim 1, characterized in that: In step S5, the sludge concentration in the membrane pool is 8000-12000 mg / L, and the residence time is 15-17 hours.

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