Multistage urea dosing device for sewage treatment system

Abstract

The utility model relates to sewage treatment technical field is a kind of multistage urea dosing device of sewage treatment system, it includes electroflocculation unit, aerobic unit, efficient anaerobic unit, urea solution preparation tank, urea solution storage tank, and aerobic unit includes first aerobic tank, second aerobic tank, ammonia nitrogen detector is fixedly arranged on second aerobic tank, first sewage delivery pipeline is fixedly connected between electroflocculation unit and aerobic unit, second sewage delivery pipeline is communicated between the outlet of aerobic unit and the import of efficient anaerobic unit, first urea solution pipeline is communicated between the outlet of urea solution storage tank and first sewage delivery pipeline, second urea solution pipeline is communicated between first urea solution pipeline and second sewage delivery pipeline, and fourth urea solution pipeline is also communicated in the import of second aerobic tank.The utility model is reasonable and compact in structure, convenient to use, and it keeps ammonia nitrogen concentration stable by steady and continuous addition of urea solution, improves the conversion capacity of microorganism to organic matter in sewage.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment technology and is a multi-stage urea dosing device for a wastewater treatment system. Background Technology

[0002] Industrial wastewater treatment technology is a technical system for treating pollutant-containing wastewater generated in industrial production, encompassing physical, biological, and chemical methods. Its core methods include physical methods (gravity separation, flotation), biological methods (activated sludge process, biofilm process), and chemical methods (coagulation, oxidation-reduction), and are divided into primary treatment for removing suspended solids, secondary treatment for degrading organic matter, and tertiary treatment for deep purification.

[0003] The entire process begins with raw wastewater passing through a coarse screen, then being pumped up by a wastewater lift pump. After passing through a screen or sand filter, it enters a grit chamber. The wastewater, after sand-water separation, enters a primary sedimentation tank – this constitutes primary treatment (i.e., physical treatment). The effluent from the primary sedimentation tank enters biological treatment equipment, including activated sludge and biofilm processes (activated sludge reactors include aeration tanks and oxidation ditches; biofilm processes include biofilters, rotating biological contactors, biological contact oxidation, and biological fluidized beds). The effluent from the biological treatment equipment enters a secondary sedimentation tank. The effluent from the secondary sedimentation tank is then disinfected before being discharged or enters tertiary treatment. This completes the primary treatment phase, which is now secondary treatment. Tertiary treatment includes biological nitrogen and phosphorus removal, coagulation sedimentation, sand filtration, activated carbon adsorption, ion exchange, and electrodialysis. Part of the sludge from the secondary sedimentation tank is returned to the primary sedimentation tank or biological treatment equipment, while another part enters a sludge thickening tank, then a sludge digestion tank. After dewatering and drying, the sludge is finally utilized. In the process of biodegradation of pollutants in industrial wastewater, insufficient nitrogen source has become a key factor limiting the treatment effect. Currently, most nitrogen sources are added manually with solid urea granules, which has a long time span for one-time addition and a long idle time, resulting in poor effect.

[0004] Therefore, it is essential to research and develop a multi-stage urea dosing device for a wastewater treatment system. Summary of the Invention

[0005] This invention provides a multi-stage urea dosing device for a wastewater treatment system, which overcomes the shortcomings of the prior art and can effectively solve the problems of unstable nitrogen source and low drug utilization rate in the existing industrial wastewater biodegradation treatment process, thus affecting the wastewater treatment effect.

[0006] The technical solution of this utility model is achieved through the following measures: a multi-stage urea dosing device for a sewage treatment system, including an electrocoagulation unit, an aerobic unit, a high-efficiency anaerobic unit, and a urea unit. A first sewage conveying pipeline is fixedly connected between the outlet of the electrocoagulation unit and the top inlet of the aerobic unit. A second sewage conveying pipeline is fixedly connected between the bottom outlet of the aerobic unit and the top inlet of the high-efficiency anaerobic unit. A third sewage conveying pipeline is fixedly connected between the bottom outlet of the high-efficiency anaerobic unit. A first urea solution pipeline is fixedly connected between the outlet of the urea unit and the first sewage conveying pipeline. A second urea solution pipeline is fixedly connected between the first urea solution pipeline and the second sewage conveying pipeline.

[0007] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution: The aforementioned urea unit includes a urea solution preparation tank and a urea solution storage tank. A first urea solution pipeline is fixedly connected between the lower outlet of the urea solution storage tank and the first sewage delivery pipeline. A third urea solution pipeline is fixedly connected between the lower outlet of the urea solution preparation tank and the top inlet of the urea solution storage tank.

[0008] The aforementioned aerobic unit includes a first aerobic tank and a second aerobic tank. The top inlet of the first aerobic tank is fixedly connected to a first sewage delivery pipeline, and the bottom outlet of the second aerobic tank is fixedly connected to the top inlet of the high-efficiency anaerobic unit via a second sewage delivery pipeline.

[0009] A fourth urea solution pipeline is fixedly connected between the first urea solution pipeline and the second aerobic tank, which is located between the second urea solution pipeline and the first sewage delivery pipeline.

[0010] Both the urea solution preparation tank and the urea solution storage tank mentioned above are equipped with a stirrer.

[0011] A urea solution delivery pump, a urea solution addition pump, a first sewage lift pump, and a second sewage lift pump are respectively fixedly installed on the aforementioned third urea solution pipeline, the first urea solution pipeline between the urea solution storage tank and the second urea solution pipeline, the first sewage delivery pipeline between the first urea solution pipeline and the first aerobic tank, and the second sewage delivery pipeline between the second urea solution pipeline and the high-efficiency anaerobic unit.

[0012] A first regulating valve and a first flow meter are fixedly installed on the first sewage conveying pipeline between the inlet of the first sewage conveying pipeline and the first urea solution pipeline in sequence according to the flow direction of the medium. A first switching valve is fixedly installed on the first urea solution pipeline between the fourth urea solution pipeline and the first sewage conveying pipeline.

[0013] An ammonia nitrogen detector is fixedly installed on the second aerobic tank, and a second switch valve is fixedly installed on the fourth urea solution pipeline.

[0014] A third regulating valve and a second flow meter are fixedly installed on the second sewage delivery pipeline between the second aerobic tank and the second urea solution pipeline in sequence according to the flow direction of the medium. A third switching valve is fixedly installed on the second urea solution pipeline 6.

[0015] The above also includes a PLC controller, a urea solution delivery pump, a urea solution filling pump, a first sewage lift pump, a second sewage lift pump, a first regulating valve, a first flow meter, a first switching valve, an ammonia nitrogen detector, a second switching valve, a third regulating valve, a second flow meter, and a third switching valve, all of which are electrically connected to the PLC controller. Interlocks are respectively set between the first regulating valve and the first flow meter, and between the third regulating valve and the second flow meter.

[0016] This utility model has a reasonable and compact structure and is easy to use. It adjusts the amount of urea solution added to the first aerobic tank and the high-efficiency anaerobic unit based on the real-time flow rate of sewage and the COD detection data of sewage. Based on the detection data feedback of the ammonia nitrogen detector, it adjusts the amount of urea solution added to the second aerobic tank. This achieves the purpose of stable and continuous addition of urea solution to the aerobic unit and the high-efficiency anaerobic unit, solving the problem of microbial activity fluctuations caused by intermittent nitrogen source addition. This increases the urea utilization rate by 40%, improves the decomposition and conversion rate of organic matter in sewage, and reduces labor costs. Attached Figure Description

[0017] Appendix Figure 1 This is a schematic diagram of the process flow of this utility model.

[0018] The codes in the attached diagram are as follows: 1 is the high-efficiency anaerobic unit, 2 is the first sewage delivery pipeline, 3 is the second sewage delivery pipeline, 4 is the third sewage delivery pipeline, 5 is the first urea solution pipeline, 6 is the second urea solution pipeline, 7 is the urea solution preparation tank, 8 is the urea solution storage tank, 9 is the third urea solution pipeline, 10 is the first aerobic tank, 11 is the second aerobic tank, 12 is the fourth urea solution pipeline, 13 is the agitator, 14 is the urea solution delivery pump, 15 is the urea solution addition pump, 16 is the first sewage lift pump, 17 is the second sewage lift pump, 18 is the first regulating valve, 19 is the first flow meter, 20 is the first switch valve, 21 is the ammonia nitrogen detector, 22 is the second switch valve, 23 is the third regulating valve, 24 is the second flow meter, 25 is the third switch valve, and 26 is the electrocoagulation unit. Detailed Implementation

[0019] This utility model is not limited to the following embodiments, and the specific implementation method can be determined according to the technical solution of this utility model and the actual situation.

[0020] Unless otherwise specified, all equipment and devices used in this invention are existing, publicly known, and commonly used equipment and devices in the field.

[0021] In this utility model, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.

[0022] The present invention will be further described below with reference to the embodiments and accompanying drawings: Example 1: As shown in the attached document Figure 1 As shown, the multi-stage urea dosing device of the wastewater treatment system includes an electrocoagulation unit 26, an aerobic unit, a high-efficiency anaerobic unit 1, and a urea unit. A first wastewater conveying pipeline 2 is fixedly connected between the outlet of the electrocoagulation unit 26 and the top inlet of the aerobic unit. A second wastewater conveying pipeline 3 is fixedly connected between the bottom outlet of the aerobic unit and the top inlet of the high-efficiency anaerobic unit 1. A third wastewater conveying pipeline 4 is fixedly connected between the bottom outlet of the high-efficiency anaerobic unit 1. A first urea solution pipeline 5 is fixedly connected between the outlet of the urea unit and the first wastewater conveying pipeline 2. A second urea solution pipeline 6 is fixedly connected between the first urea solution pipeline 5 and the second wastewater conveying pipeline 3.

[0023] In this invention, industrial wastewater from the production unit, after adjusting the pH value of the system, passes through the electrocoagulation unit 26 to remove pollutants such as heavy metals, grease, and COD. It then enters the aerobic unit via the first wastewater transport pipeline 2, where microbial degradation removes pollutants, resulting in pre-treated wastewater. This pre-treated wastewater then enters the high-efficiency anaerobic unit 1, where organic matter is further degraded. During this process, the required nitrogen source is supplied to the aerobic unit and the high-efficiency anaerobic unit 1 via the first urea solution pipeline 5 and the second urea solution pipeline 6, respectively (the high-efficiency anaerobic unit 1 is typically an anaerobic environment with a carbon source: nitrogen source: phosphorus source concentration ratio of 100:5:1). The treated wastewater then flows out via the third wastewater transport pipeline 4 for subsequent processing.

[0024] As needed, the electrocoagulation unit 26 uses alloy metals such as aluminum and iron as electrodes to generate metal cationic flocculants through electrochemical reactions. It is a water treatment technology that uses the synergistic effects of electrolytic oxidation, electrolytic reduction, electrolytic flocculation and electrolytic flotation to remove pollutants. This technology adopts a high-voltage and low-current mode and can treat pollutants such as heavy metals, grease and COD.

[0025] The high-efficiency anaerobic unit 1 adopts an improved ABR anaerobic baffled reactor. Each reactor group is designed with multiple partitioned zones. Porous biological carrier packing is added to each partitioned zone. By adding toxic anaerobic microorganisms, multiple relatively independent anaerobic fixed-bed reactors are connected in series, so as to carry out a chain degradation reaction on the organic matter entering the ABR anaerobic reactor, thereby achieving the gradual degradation of organic matter.

[0026] The multi-stage urea dosing device of the above-mentioned wastewater treatment system can be further optimized and / or improved according to actual needs: Example 2: Its difference from Example 1 is as follows: (See attached) Figure 1 As shown, the urea unit includes a urea solution preparation tank 7 and a urea solution storage tank 8. A first urea solution pipeline 5 is fixedly connected between the lower outlet of the urea solution storage tank 8 and the first sewage conveying pipeline 2. A third urea solution pipeline 9 is fixedly connected between the lower outlet of the urea solution preparation tank 7 and the top inlet of the urea solution storage tank 8.

[0027] As needed, after the urea solution in the urea solution preparation tank 7 is tested and found to be of acceptable concentration (usually 45% by mass), it is transported to the urea solution storage tank 8 through the third urea solution pipeline 9, and then added to the aerobic unit and the high-efficiency anaerobic unit 1 through the first urea solution pipeline 5 and the second urea solution pipeline 6, respectively.

[0028] Example 3: Its difference from Examples 1 to 2 is as follows: (See attached) Figure 1 As shown, the aerobic unit includes a first aerobic tank 10 and a second aerobic tank 11. The top inlet of the first aerobic tank 10 is fixedly connected to a first sewage conveying pipeline 2, and the bottom outlet of the second aerobic tank 11 is fixedly connected to the top inlet of the high-efficiency anaerobic unit 1 via a second sewage conveying pipeline 3.

[0029] As needed, the wastewater in the first aerobic tank 10 overflows into the second aerobic tank 11. Both the first aerobic tank 10 and the second aerobic tank 11 employ biofilm technology using biofilm carrier carbon. The biofilm carrier used is 40-200 mesh powdered carbon. Microorganisms grow on the powdered carbon. Because the 40-200 mesh powdered carbon is easily and evenly distributed within the aerobic unit under aeration, it not only provides a biofilm carrier for microbial growth, but also has a strong adsorption capacity for organic matter in the water within the aerobic unit, which is more conducive to the degradation and removal of pollutants in the wastewater by microorganisms.

[0030] Example 4: Its difference from Examples 1 to 3 is as follows: (See attached) Figure 1 As shown, a fourth urea solution pipeline 12 is fixedly connected between the first urea solution pipeline 5, which is between the second urea solution pipeline 6 and the first sewage delivery pipeline 2, and the second aerobic tank 11.

[0031] As needed, urea solution can be directly added to the second aerobic tank 11 through the fourth urea solution pipeline 12 to ensure that the ammonia nitrogen concentration in the second aerobic tank 11 reaches the required concentration.

[0032] Example 5: It differs from Examples 1 to 4 in that, as shown in the appendix... Figure 1 As shown, both the urea solution preparation tank 7 and the urea solution storage tank 8 are equipped with a stirrer 13.

[0033] As needed, a stirrer 13 is installed in the urea solution preparation tank 7 to facilitate the rapid dissolution of solute during urea solution preparation. A stirrer 13 is also installed in the urea solution storage tank 8 to prevent solute sedimentation and ensure uniform solution concentration in the urea solution storage tank 8.

[0034] Example 6: Its difference from Examples 1 to 5 is as follows: (See attached) Figure 1 As shown, a urea solution delivery pump 14, a urea solution addition pump 15, a first sewage lift pump 16, and a second sewage lift pump 17 are respectively fixedly installed on the third urea solution pipeline 9, the first urea solution pipeline 5 between the third urea solution pipeline 9, the urea solution storage tank 8 and the second urea solution pipeline 6, the first sewage delivery pipeline 2 between the first urea solution pipeline 5 and the first aerobic tank 10, and the second sewage delivery pipeline 3 between the second urea solution pipeline 6 and the high-efficiency anaerobic unit 1.

[0035] As needed, the urea solution is equipped with a metering pump 15, which allows for precise adjustment and metering of the amount of urea solution added by adjusting the pump speed.

[0036] Example 7: Its difference from Examples 1 to 6 is as follows: (See attached) Figure 1 As shown, a first regulating valve 18 and a first flow meter 19 are fixedly installed on the first sewage pipeline 2 between the inlet of the first sewage pipeline 2 and the first urea solution pipeline 5 in sequence according to the flow direction of the medium. A first switching valve 20 is fixedly installed on the first urea solution pipeline 5 between the fourth urea solution pipeline 12 and the first sewage pipeline 2.

[0037] Example 8: It differs from Examples 1 to 7 in that: as shown in the appendix Figure 1 As shown, an ammonia nitrogen detector 21 is fixedly installed on the second aerobic tank 11, and a second switch valve 22 is fixedly installed on the fourth urea solution pipeline 12.

[0038] As needed, the ammonia nitrogen detector 21 can be the WDet-50000 model online automatic ammonia nitrogen water quality analyzer provided by Hangzhou Zetian Technology Co., Ltd.

[0039] Example 9: It differs from Examples 1 to 8 in that: as shown in the appendix Figure 1 As shown, a third regulating valve 23 and a second flow meter 24 are fixedly installed on the second sewage conveying pipeline 3 between the second aerobic tank 11 and the second urea solution pipeline 6 in sequence according to the flow direction of the medium, and a third switching valve 25 is fixedly installed on the second urea solution pipeline 6.

[0040] Example 10: It differs from Examples 1 to 9 in that, as shown in the appendix... Figure 1As shown, it also includes a PLC controller, a urea solution delivery pump 14, a urea solution filling pump 15, a first sewage lift pump 16, a second sewage lift pump 17, a first regulating valve 18, a first flow meter 19, a first switching valve 20, an ammonia nitrogen detector 21, a second switching valve 22, a third regulating valve 23, a second flow meter 24, and a third switching valve 25, all of which are electrically connected to the PLC controller. Interlocks are respectively set between the first regulating valve 18 and the first flow meter 19, and between the third regulating valve 23 and the second flow meter 24.

[0041] As needed, the flow rate of wastewater entering the first aerobic tank 10 is adjusted according to the COD detection value in the industrial wastewater. When the operator detects a high COD value, the opening of the first regulating valve 18 is reduced, and when the COD value is detected to be low, the opening of the first regulating valve 18 is increased. At the same time, the flow rate of the first aerobic tank 10 is monitored by the first flow meter 19, and the flow rate of the wastewater entering the high-efficiency anaerobic unit 1 is adjusted synchronously by adjusting the opening of the third regulating valve 23.

[0042] Based on the required flow rate of the first flow meter 19 and the COD detection value in the wastewater, after determining the amount of urea solution to be added, the second switch valve 22 and the third switch valve 25 are closed, the first switch valve 20 is opened, and the amount of urea solution added to the first aerobic tank 10 is controlled by adjusting the speed of the urea solution adding pump 15.

[0043] Normally, the ammonia nitrogen level in the second aerobic tank 11 is kept constant. The amount of urea solution added is determined based on the ammonia nitrogen level detected by the ammonia nitrogen detector 21 in the second aerobic tank 11. When the ammonia nitrogen level is below 8 mg / L, the first switch valve 20 and the third switch valve 25 are closed, and the second switch valve 22 is opened. The amount of urea solution added to the second aerobic tank 11 is controlled by adjusting the speed of the urea solution adding pump 15. When the ammonia nitrogen level is above 8 mg / L, the second switch valve 22 is closed, and the urea solution adding is stopped.

[0044] The high-efficiency anaerobic unit 1 is usually dominated by an anaerobic environment. The carbon source: nitrogen source: phosphorus source concentration ratio in the high-efficiency anaerobic unit 1 is 100:5:1. After determining the amount of urea solution to be added in the high-efficiency anaerobic unit 1 based on the analysis and detection data, the first switch valve 20 and the second switch valve 22 are closed, and the third switch valve 25 is opened. The amount of urea solution added is controlled by adjusting the speed of the urea solution adding pump 15.

[0045] Depending on the needs, the pipelines and equipment of the multi-stage urea dosing unit in this wastewater treatment system can also be equipped with conventional valves, thermometers, and pressure gauges known in the art, according to production requirements. The PLC controller can be a Siemens S7-1500, which is equipped with a Yokogawa CS3000 DCS control system.

[0046] The above technical features constitute various embodiments of this utility model, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

[0047] The usage process of this utility model is as follows: First, industrial wastewater is treated by electrocoagulation unit 26 to remove pollutants such as heavy metals, grease, and COD. Then, it is transported to the first aerobic tank 10 via the first wastewater transport pipeline 2 and the first wastewater lift pump 16. At the same time, urea solution is added to the industrial wastewater via the first urea solution pipeline 5. Next, the industrial wastewater overflows from the first aerobic tank 10 to the second aerobic tank 11. The amount of urea solution added to the second aerobic tank 11 is adjusted according to the ammonia nitrogen detection value of the ammonia nitrogen detector 21. Finally, the pre-treated wastewater, after being treated by microorganisms in the first aerobic tank 10 and the second aerobic tank 11, is transported to the high-efficiency anaerobic unit 1 via the second wastewater lift pump 17. The organic matter in the unit is further degraded. The treated wastewater then flows out via the third wastewater transport pipeline 4 for subsequent processing.

Claims

1. A multi-stage urea dosing device for a wastewater treatment system, characterized in that... It includes an electrocoagulation unit, an aerobic unit, a high-efficiency anaerobic unit, and a urea unit. A first sewage delivery pipeline is fixedly connected between the outlet of the electrocoagulation unit and the top inlet of the aerobic unit. A second sewage delivery pipeline is fixedly connected between the bottom outlet of the aerobic unit and the top inlet of the high-efficiency anaerobic unit. A third sewage delivery pipeline is fixedly connected between the bottom outlet of the high-efficiency anaerobic unit. A first urea solution pipeline is fixedly connected between the outlet of the urea unit and the first sewage delivery pipeline. A second urea solution pipeline is fixedly connected between the first urea solution pipeline and the second sewage delivery pipeline.

2. The multi-stage urea dosing device for a wastewater treatment system according to claim 1, characterized in that urea... The unit includes a urea solution preparation tank and a urea solution storage tank. A first urea solution pipeline is fixedly connected between the lower outlet of the urea solution storage tank and the first sewage conveying pipeline. A third urea solution pipeline is fixedly connected between the lower outlet of the urea solution preparation tank and the top inlet of the urea solution storage tank.

3. The multi-stage urea dosing device for a wastewater treatment system according to claim 1 or 2, characterized in that... The aerobic unit includes a first aerobic tank and a second aerobic tank. The top inlet of the first aerobic tank is fixedly connected to a first sewage delivery pipeline, and the bottom outlet of the second aerobic tank is fixedly connected to the top inlet of the high-efficiency anaerobic unit via a second sewage delivery pipeline.

4. The multi-stage urea dosing device for a wastewater treatment system according to claim 3, characterized in that... A fourth urea solution pipeline is fixedly connected between the first urea solution pipeline and the second aerobic tank, which is located between the second urea solution pipeline and the first sewage delivery pipeline.

5. The multi-stage urea dosing device for a wastewater treatment system according to claim 2 or 4, characterized in that... Both the urea solution preparation tank and the urea solution storage tank are equipped with a stirrer.

6. The multi-stage urea dosing device for a wastewater treatment system according to claim 5, characterized in that... A urea solution delivery pump, a urea solution addition pump, a first sewage lift pump, and a second sewage lift pump are respectively fixedly installed on the third urea solution pipeline, the first urea solution pipeline between the urea solution storage tank and the second urea solution pipeline, the first sewage delivery pipeline between the first urea solution pipeline and the first aerobic tank, and the second sewage delivery pipeline between the second urea solution pipeline and the high-efficiency anaerobic unit.

7. The multi-stage urea dosing device for a wastewater treatment system according to claim 4 or 6, characterized in that... A first regulating valve and a first flow meter are fixedly installed on the first sewage conveying pipeline between the inlet of the first sewage conveying pipeline and the first urea solution pipeline, in sequence according to the flow direction of the medium. A first switching valve is fixedly installed on the first urea solution pipeline between the fourth urea solution pipeline and the first sewage conveying pipeline.

8. The multi-stage urea dosing device for a wastewater treatment system according to claim 7, characterized in that... An ammonia nitrogen detector is fixedly installed on the second aerobic tank, and a second switch valve is fixedly installed on the fourth urea solution pipeline.

9. The multi-stage urea dosing device for a wastewater treatment system according to claim 4, 6, or 8, characterized in that... A third regulating valve and a second flow meter are fixedly installed on the second sewage delivery pipeline between the second aerobic tank and the second urea solution pipeline in sequence according to the flow direction of the medium. A third switch valve is fixedly installed on the second urea solution pipeline.

10. The multi-stage urea dosing device for a wastewater treatment system according to claim 9, characterized in that... It also includes a PLC controller, a urea solution delivery pump, a urea solution filling pump, a first sewage lift pump, a second sewage lift pump, a first regulating valve, a first flow meter, a first switching valve, an ammonia nitrogen detector, a second switching valve, a third regulating valve, a second flow meter, and a third switching valve, all of which are electrically connected to the PLC controller. Interlocks are respectively set between the first regulating valve and the first flow meter, and between the third regulating valve and the second flow meter.

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