Superior Degradation characteristics of industrial wastewater treated by Biological and 3D Electrochemical Coupling Process

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The process parameters were investigated.Result showed that the system could remove over 99.13% COD,63.88% TN,99.42% TP and 25.0% NH 3 -N in 2h. Under the operating conditions of voltage 8V, electrolysis 120min, addition of 2000mg/L electrolyte KCl and 30g industrial waste steel slag, the degradation of pollutants is effectively improved. And through economic analysis, it can be calculated that it only costs 2.2CNY/t to process one ton of industrial wastewater. The experimental results not only meet the water discharge standards, but also pave the way for developing techniques with high efficiency, economy, low energy consumption and universal use. Bio-electrochemical coupling Industrial waste Advanced processing 3D-electrolysis Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction With the rapid development of the social economy, the technology of industry has greatly improved, and it has indeed produced a lot of economic benefits. However, at the same time, industrial wastewater has increased exponentially, which has brought a huge burden on the environment and affected people's daily water quality as well. It is well known that the characteristics of industrial wastewater are mainly manifested in large discharge, complex composition and severe pollution. Therefore, there are great difficulties in treating industrial wastewater 1 . China's initial implementation of industrial wastewater treatment has achieved certain experience so far. The effectiveness of wastewater treatment capacity is obvious. It can meet a wide range of industrial wastewater treatment on the basis, but the treatment technology is still immature. In some small and medium-sized factories, in order to save money, the wastewater treatment process is simplified, and the sewage treatment is not done enough. After discharge, the surrounding water bodies and the environment will still be polluted. Therefore, developing techniques with low-energy consumption and high efficiency is urgently needed 2 . Pollutants can be removed from wastewater using electrochemical treatment, and it is an environmentally friendly technology 3,4,5 .In particular, it has received more and more attention in environmental pollution control. Although electrochemical technology started late in China's sewage treatment, its development speed is extremely rapid 6 .It has been applied in many fields of environmental chemical engineering up to now 7 .This method exploits an electrochemical cell with a cathode and an anode that is leached in the effluent. The utilize of an electric current reasons redox reactions at the electrodes 8 .In the past a few years, the bio-electrochemical coupling process has emerged and develops fast since it can deeply treat wastewater 9,10 , and is widely used in the removal of pollutants in sewage due to its high efficiency, low consumption and relatively low cost. This technique is quite mature in western countries. In the past decade, some researches have been reported on the bio-electrochemical technology used to degrade pollutants in wastewater. For example, Ricardo A et al. used electrochemical-bio-coupling to treat industrial wastewater containing 5-amino-6-methyl-2-benzimidazolone and found that the pollutants can be removed effectively 11 .Yu et al designed a special centrifugal electrode reactor for the electrochemical treatment of wastewater including heavy metals. To make better the treatment of mimeticed heavy metal wastewater operating an aluminium anode 12 .Therefore, the research of electrochemical coupling technology in wastewater treatment is more and more important. In the meanwhile, the traditional 2D-electrochemical has some shortcomings, such as low effective current and small effective surface area, while three-dimensional electrochemical technology which means that additional component is added into the process can make up for these shortcomings 11 . Because of the many advantages of the three-dimensional (3-D) electrochemical oxidation reactor over the conventional electrochemical oxidation reactor, the 3D electrochemistry method has received much attention these days 13 . Moreover, in recent years, the concept of “waste utilization” is highly valued in the field of water treatment 14,15,16 . Among them, Steel slag, a representative industrial waste, has been well utilized in some areas. For example, its good adsorption and sedimentation performance can remove pollutants from water and soil obviously 17,18 .The annual output of steel slag, a by-product of steelmaking in the world, is as high as 50 million tons 19,20 , and the number of steel slag that can be reasonably utilized in China is low and no more than 20%. Therefore, the rational use of steel slag is very urgent 21 At present, the abundant metal resources have been neglected by the research process of steel slag, which leads to the great limitation of steel slag application in the field of water treatment. Studies have shown that the electro-Fenton process occurs in the three-dimensional electrode of steel slag because of the presence of Fe element, so it can effectively degrade organic matter 22,23,24 .In particular, some organic residues after secondary treatment of refinery wastewater are biologically toxic, and three-dimensional electrode technology can effectively select organic matter in the deep treatment process to better degrade organic matter 25 .In addition, the presence of Fe element makes the steel slag particles magnetic, which provides convenience for recycling of the technology. Based on the above description, In the present work, the purpose of this study is to improve the treatment efficiency of secondary effluent by first using a biological process as the pretreatment of wastewater 26 and then combining with the three-dimensional electrode to form an electrochemical reaction to deeply treat the secondary effluent. We will choose the steel slag as a component of the particle electrode, which can better enhance the degradation efficiency of COD and TN mainly in the electrochemical reactor. It is expected that waste utilization of industrial waste can be effectively achieved while both reaction time and cost are reduced during the process. 2. Materials and methods 2.1 Water quality characteristics The raw water in this study is the drainage of the wastewater treatment plant in Lanzhou Petrochemical Company of Gansu in China. The raw water quality is shown in Table 1 . The wastewater used in the electrochemical experiments was collected from wastewater in aeration tanks in the large-scale wastewater treatment facilities. Prior to the start of the electrochemical experiment, the water samples were stored in 20 L polyethylene drums in dark at 4℃ before use. Table 1 Characteristics of Raw water quality parameter Numerical range average value COD(mg/L) 423–450 436.5 TN(mg/L) 48-47.9 47.95 TP(mg/L) 3.16–3.43 3.3 NH 3 -N(mg/L) 14.7–15.8 15.3 pH 7.78–7.84 7.81 2.2 Experimental set-up Degradation experiments were performed in a lab-scale reactor as is shown in Fig. 1 .Biological treatment device utilizes physical, chemical, physical and chemical methods, and adopts a combination of oil-repellent precipitation-homogeneous-hydrolysis acidification-A/O (anoxia/aerobic)-aeration process, through various treatment facilities and auxiliary facilities, mainly to remove pollutants from the petrochemical plant wastewater 27 .As shown in the electrochemical reaction part of Fig. 1 .Set the electrochemical device as Test Device 1 and Test Device 2.The Test Device 1 was a static two dimensional system(no using steel slag).The Test Device 2 was a static three dimensional system. The static three dimensional device, which consists of 5L electrolytic cell, electrode plate, power supply, electric wire, industrial scrap slag, peristaltic pump, etc., and is electrolyzed by a single group of electrodes, wherein the anode plate is a titanium plate and the cathode is a DAS electrode plate. Set the electrochemical device as Test Device 1 and Test Device 2. The Test Device 1 was a static two dimensional system. The Test Device 2 was a static three dimensional system. 2.3 Chemical and experimental equipment This section only introduces the chemicals and experimental equipment used in the electrochemical experiment. The experimental drugs are divided into three categories according to the use conditions in the experimental process: the first type is the medicines required before the experiment, and is mainly used for the configuration of the standard stock solution; the second type is the medicines required during the experiment. For example, KCl is used as an electrolyte; the third type is a reagent used to analyze various water quality indicators at the end of the experiment. The chemicals used in the experiment are KCl, Ag 2 SO 4 , HgSO 4 , K 2 Cr 2 O 7 , NaOH, K 2 S 2 O 8 , H 2 SO 4 (98%), HCl, and the like. These chemicals were obtained from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). The chemical reagent is at least with analytical grade. It can be used without further purification. The solutions prepared in the experiments were all deionized water having a pH of 6.8. The instruments and equipment used in the experiment mainly include DC stabilized steady current power supply(KEYSIGHT.U8002A),ultrasonic cleaner(CNC.KQ3200DV,Kunshan,China), constant temperature drying oven, UV-visible spectrophotometer, COD digestion instrument(HASH.COD Reactor.WD325),COD rapid measuring instrument(ENOVI/NANNA), magnetic heating stirrer, and electronic equality. In addition, there are instruments and equipment commonly used in general laboratories. 2.4 Analytical method First add the effluent from the 2L aeration tank to the electrolytic cell with a volume of 5L, then add a certain proportion of KCl electrolyte, and stir evenly. A titanium plate and an DAS electrode plate having a surface area of 10 cm*1 cm were selected as the anode and the cathode, respectively, and the plate spacing was set to be not less than 15 cm. The two electrode plates are connected to the positive and negative electrodes of the direct current power source, respectively. In the experimental apparatus 2, the pretreated steel slag was filled in the bottom of the electrolytic cell in a certain ratio and the pH of the sewage was adjusted to 6.8–7.5.When the experimental device is ready, turn on the power, select the appropriate voltage, and sample regularly to measure the water quality indicators. The steel slag used in the experiment was taken from the Yuzhong Iron and Steel Plant in Lanzhou, Gansu Province. Its appearance and composition are shown in Fig. 1 . The COD in this experiment is measured by the rapid digestion spectrophotometry. (HJ/T 399–2007) The measurement method of TN is alkaline potassium persulfate digestion ultraviolet spectrophotometry(HJ 636–2012), the measurement method of NH 3 -N is Nessler reagent spectrophotometry(HJ 535–2009), and the TP is measured with a molybdenum Acid spectrophotometry(GB 11893-89). 3. Results and discussion 3.1 Water quality of effluent After the sewage from the chemical plant is treated by physical, chemical, biochemical and other processes, the effluent from the aeration tank is selected to test the pollutants. The water quality after biological treatment is shown in Table 2 . Table 2 Characteristics of water quality parameter GB value Biological method Electrochemistry2D Electrochemistry3D COD(mg/L) 60 78 5.2 3.8 TN(mg/L) 40 29.5 21.41 17.32 TP(mg/L) 1.0 0.018 — — NH 3 -N(mg/L) 8.0 0.68 — — pH 6–9 7.44 8.76 8.23 According to the water quality of the secondary effluent, it is noticed that the four indicators basically meet the national first-class discharge standards for industrial wastewater, especially the content of TP and NH 3 -N has degraded to a very good condition. However, the content of COD and TN needs further eliminated,. The next step, we put focus on the degradation of COD and TN. 3.2 Steel slag electrode characterization In order to study the surface morphology and crystal structure of steel slag, the slag was characterized by SEM, EDS, XRD and VSM. Figure 2 (a) shows the surface morphologies of the steel slag particle used in the experiment. It can be seen that the surface of the steel slag is mainly rugged and irregular, has high porosity. From the SEM image, it can be inferred that the diameters of the pores are micrometer range. High porosity helps to improve the adsorb-ability of the steel slag particle. The atomic percentage of all components that the steel slag particle are mainly contained can be showed on (b).from the (b) can be showed that atomic percentage of steel slag particle are mainly composed of O C Ca Mg and Fe. (c) shows the XRD pattern of the steel slag, the results show that the composition and crystal structure of steel slag are relatively complicated. By comparing the standard cards of the Joint Committee on Powder Diffraction Standards, it can be seen that the main elements are in the form of compounds. Oxygen, silicon, calcium are mainly in the form of crystalline quartz SiO 2 (JCPDS, 46e1045) and calcium silicate Ca 2 SiO 4 (JCPDS, 39e1346), ) exist in the Steel slag, and CaO (JCPDS, 28–0775) can be seen on the XRD patterns too.Fe 2 O 3 with crystalline phases of hematite (JCPDS, 33–0664) and maghemite C (JCPDS, 39-1346), FeO with iron ore phases (JCPDS, 46-1312) and Fe 3 O 4 with cubic crystal phase (JCPDS, 65-3107) can be detected in the Steel slag. It can be indicated that steel slags have complex crystal structures. On the (d) can displayed the steel slag of magnetic characterization. In the light of (d),the steel slag particle is magnetic, and the hysteresis regression line presented uniformly symmetrical S-shaped curve. The saturation magnetic intensity of the steel slag particle are powerful. The magnetism of the steel slag particles would be momentous for recycle. 3.3 Influence and optimization of operating parameters 3.3.1 Voltage effect Experimental conditions: The effective area of the cathode yin and anodeelectrode plates is 7.5 cm*1 cm. The electrode spacing was 17 mm, and 2000 mg/L of KCl was added as an electrolyte. The water quality is not adjusted during the reaction, and the effect of the treatment system on the secondary effluent is directly analyzed. Using the experimental device 1, the effect of COD and TN treatment was investigated by changing the voltage, and the effect of different voltages on the removal of pollutants in the actual sewage was compared. Figure 3 (a) and (b)shows the results. It can be seen from the figure that as the voltage increases, the degradation efficiency of COD and TN also increases, and the content of COD and TN decreases overall. Therefore, it can be deduced that the increase in voltage is beneficial to the degradation of COD and TN. In order to determine the optimum voltage, the electrolysis time is set to 120 min. We extract the COD and TN values corresponding to each voltage from Fig. 3 , the estimated degradation efficiency of COD and TN is shown in Fig. 3 (c). It can be seen from the blue curve in the Fig. 3 (c) that as the voltage increases, the degradation efficiency of COD also continues to increase. Increasing the voltages from 0 to 4, the degradation efficiency of COD increases obviously. When the voltage reaches 8V, the degradation rate can reach 91.03%.Continue to increase the voltage, there is almost no obvious change, so 8V is the saturated value for the optimal degradation efficiency of COD. The subsequent electrolysis experiment is then carried out at the voltage of 8v. The red curve in the figure shows the degradation effect of TN under different voltage conditions. It can be seen that when the voltage is increased to 8V, the degradation rate of TN can reach 27%. When the voltage is continuously increased to 10V, the removal rate of TN is decreased, which may be caused by an increase in voltage inducing an oxidation reaction during electrolysis, and finally results in an increase in the content of TN. Similarly, 8v is selected as the optimum voltage in combination with the removal state of the contaminant by the voltage. 3.3.2 time Shown in Fig. 3 (d).It is noted that when the voltage is constant, the degradation effect of COD and TN changes with time, and the elongation of electrolysis time causes the content of COD and TN to gradually decrease. When the electrolysis time reaches 120 minutes, the downward trend becomes slower. Even electrolysis continues, the COD removal is still within 5 mg/L, the TN removal is still within 20 mg/L. Therefore, it is meaningless to extend the electrolysis time.120 minutes is the best electrolysis time in the present study. The impact of the water quantity factor is also considered. Figure 3 (e) shows the relationships of removing COD and duration with different amounts of water. It can be seen that the difference in water quantity under certain conditions will have a certain influence on the degradation rate of COD. When the amount of water treated is increased from 2L to 3.5L, the treatment effect tends to decrease. The removal rates differ by 15%-25% depending on the processing duration. Therefore, when the amount of water changes, it can be considered to increase the electrode group to ensure the treatment effect of the system on sewage. 3.3.3 Electrolyte effect In this section, the effect of different electrolyte concentrations on the degradation rate of pollutants in water was observed. In this experiment, the electrolyte concentration was controlled in a range from 500mg/L to 5000mg/L. Six different concentrations were analyzed of 500mg/L,1000 mg/L ,2000mg/L, 3000mg/L, 4000mg/L and 5000mg/L to observe the degradation of COD and TN. The results are shown in Fig. 3 (f), respectively. The blue curve in Fig. 3 (f) mainly examines the effect of different concentrations of electrolyte on the rate of COD degradation. It can be seen that the addition of Cl − has a certain help to the degradation of COD. When the dosage of Cl − reaches 2000mg/L, the degradation rate of COD can reach as high as 91.03%. The red curve in Fig. 3 (f) shows the effect of different electrolyte concentrations on the degradation rate of TN at a reaction time of 120 minutes and a voltage of 8 V. It can be seen from the figure that the dosage of electrolyte can effectively promote the degradation of TN, and the degradation rate changes with the change of electrolyte concentration. The main reason may be that Cl − will produce active Cl − with short life but with strong oxidative property during electrolysis. As the concentration of Cl increases, the degradation rate of TN increases significantly. The higher the concentration, the more obvious the tendency of the degradation rate to increase. When the dosage of Cl − reaches 5000mg/L, the degradation rate of TN reaches 28.9%.It can be seen that Cl − gradually undergoes electrolysis under electrochemical action, producing effective Cl, thereby increasing the removal of TN. The reaction process is as follows: Anode: 2Cl − →Cl 2 + 2e ( 1 ) Cathode:2H 2 O + 2e − →H 2 + 2OH − ( 2 ) Solution:Cl 2 + H 2 O→HClO + H + +Cl − ( 3 ) It can be seen that Cl − not only can rapidly generate substances with strong oxidizing properties such as Cl, but also can improve the conductivity in the solution. The current intensity through the electrodes in a unit time also increases, thus affecting the degradation of TN. Based on the comparison of the above various factors, Fig. 4 compares the degradation of TN at different concentrations. Although the electrolytes with a concentration of 5000mg/L has a better degradation effect on TN, the difference between these two is not particularly large. Therefore, in combination with the degradation rate of COD, in the three-dimensional electrode reaction experiment section, the optimum conditions were set: the electrolysis time is 120 minutes, and the voltage is 8V, the electrolyte concentration is 2000mg/L. 3.3.4 3D-electrode electrochemical reaction Through the above experiments, it can be shown that the electrochemical system has certain effects on the advanced treatment of industrial wastewater, but the treatment effect of COD and TN is still limited. In order to further improve the treatment effect of sewage, combined with the experimental results of the previous progress, industrial waste steel slag [11] was added to the two-dimensional electrode reaction. A three-dimensional electrode system is then formed by the action of steel slag to enhance the overall treatment effect on sewage. Experimental conditions: The effective area of the yin and yang electrode plates is 7.5 cm*1 cm. The electrode spacing is 17 mm, the voltage is 8 V, reaction time is 120min, the electrolyte concentration is 2000mg/L. In this case, we use the experimental device 2. The results are shown in Fig. 5 (a). As can be seen from Fig. 6 ,as the amount of steel slag increases, the COD content continuously decreases. Among them, when the amount of steel slag is added to be 30g, the degradation effect is the best. When the amount of steel slag is added to be 30g and keeps electrolysis for 120min,the degradation rate of COD can reach about 95.2%,and the degradation rate is increased by 5.8-6% at the same time compared with the two-dimensional system. In the three-dimensional system, the degradation efficiency of COD is about 92.2% when the electrolysis time is about 80 minutes, which exceeds the degradation effect in the two-dimensional system electrolyzed for 120 minutes. Therefore, it can be stated that the addition of steel slag can enhance the degradation of COD efficiently. It can be seen from Fig. 5 (b) that the effect of the addition of steel slag on TN degradation is significantly higher than that without the addition. Among them, when the amount of steel slag added is 30g, the degradation effect is the best. When the amount of steel slag added is 30g, the content of TN is reduced to about 17.32mg/L with electrolyzed for 120min.Compared with the two-dimensional system, the content of TN decreases by about 4-4.2 mg/L, and the degradation rate increased by about 14.3%. Therefore, it can be proposed that the presence of steel slag in the three-dimensional system would promote the degradation of TN as well. 3.4 Mechanism of removal of COD and TN by 3D-electrode system From the experimental analysis, the main active substance involved in the degradation of COD and TN is HO•. The possible mechanism of the removal of COD and TN with a 3D-electrochemical system in shown in Fig. 6 .In the removal process, pollutant molecules are adsorbed on the surface of the steel slag particle, and hydroxyl radicals are also generated in the boundary layer on the outer surface of the steel slag particle. The main pollutants with HO• on the surface of the steel slag particle. And a small amount of HO• diffused into the solution and continue to reacted. The addition of KCl causes Cl − to undergo electrolysis under electrochemical action, producing effective Cl and accelerating the degradation of TN. Cl − not only rapidly generates strong oxidizing substances such as active chlorine, but also improves the electrical conductivity of the solution, so that the current intensity and current density increase, thereby accelerating the degradation of COD and TN. 3.5 Economic analysis The cost of biological activated sludge process for advanced treatment wastewater in this experiment is negligible. The operating cost of the combined three-dimensional steel slag particle electrode electrochemical technology of the costs of electricity, reagents and material. which were 1.7, 0.01and 0.5 CNY/t respectively. The total operating cost was 2.2CNY/t. 4. Conclusions In summary, 3D-electrochemical system were developed from steel slag, and the experimental conditions were optimized. The steel slag particles were characterized by SEM EDS XRD and VSM, and then were used in industrial wastewater advanced treatment in a designed 3D-electrochemical system. The steel slag particles were used in 3-D system for COD and TN degradation, and exhibited high catalytic activity by increasing hydroxyl radicals in the system. The results show that the degradation rate of COD and TN in 3D-electrochemical system with steel slag particle is significantly higher than that of 2D-electrochemical system. It can be seen from the results that the 3D-electrochemical coupling can greatly improve the degradation efficiency of pollutants in the sewage. In particular, the treatment effect of COD is very promising and meets the requirements of water quality. Moreover, in view of economic analysis, it can be seen that the cost of processing water per ton is 2.2CNY/t, which meets the requirements of low energy consumption. Declarations Conflicts of interest There are no conflicts to declare. Acknowledgments The Gansu Provincial Science and Technology Major Program (21ZD4GD033), the Gansu Provincial Key R&D Projects (22YF7GD194), the Gansu Provincial Science and Technology Program (22ZY1QD001). References K.Zhe, L.Lu, X.Yi, Y.Min, Yu-You Li, Journal of Cleaner Production, 2019,231,913–927. Amishi Popat, P.V. Nidheesh, T.S. Anantha Singh, M. Suresh Kumar,Chemosphere 2019,237,124419. H.J.Lin, W.W.Liu, X. Zhang, Nicholas Williams, B. Hu, Biochemical Engineering Journal, 2017,120,146–156. K.J. Wei, C.Y. Shen, W.Q. Han, J.S.g Li, X.Y. Sun, J.Y. Shen, L.J. Wang, Chemical Engineering Journal,2017,310,13–21. R.Y. Zhu, C.Y.Yang, M.M. Zhou, J.D. Wang,Chemical Engineering Journal,2015,260.427-433. J.W.Tang, C.H.Zhang, X.L. Shi, J.J.Sun, Jeffrey A. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4822048","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":335205857,"identity":"0abf1de4-ae6d-4600-be49-8c7f9e92021f","order_by":0,"name":"Guixian Zhu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzElEQVRIiWNgGAWjYBACNmaGxIcfDP7XM7Y3HyBOCx87w2NjiQLmBOaeYwnEaZHjZ3wmwfOBOYF9Ro4BsQ5jTjaQMGDL452R8/HGGwY7Od0GglrYEh8UGPAUS/a83Ww5hyHZ2OwAQS08IFskGDe2526T5mE4kLiNsBb+bxI8BgaM+w/kPCNWC0MaUEtCYmNHDhvRWpKNJQwOGDP2HDO2nGNAhF/k+w8Ao/LPATlgVD688abCTo6gFhQAdCEpyiFaSNUxCkbBKBgFIwIAAFQCPuOTYv7DAAAAAElFTkSuQmCC","orcid":"","institution":"Northwest research institute of mining and metallurgy","correspondingAuthor":true,"prefix":"","firstName":"Guixian","middleName":"","lastName":"Zhu","suffix":""},{"id":335205858,"identity":"5d245144-e966-4dd4-ab15-a80331138de1","order_by":1,"name":"Qiang Feng","email":"","orcid":"","institution":"Northwest research institute of mining and 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metallurgy","correspondingAuthor":false,"prefix":"","firstName":"Hao","middleName":"","lastName":"Xu","suffix":""},{"id":335205862,"identity":"65868070-e81e-49a5-a436-174e8ad71ea5","order_by":5,"name":"Longfei Jia","email":"","orcid":"","institution":"northwest research institute of mining and metallurgy","correspondingAuthor":false,"prefix":"","firstName":"Longfei","middleName":"","lastName":"Jia","suffix":""}],"badges":[],"createdAt":"2024-07-29 12:37:05","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4822048/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4822048/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":63575747,"identity":"75f50707-4ea3-4206-9f26-7f9a9f873684","added_by":"auto","created_at":"2024-08-29 19:17:39","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":132328,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eBiological treatment process flow chart（1）Oil separation sedimentation tank（2）Homogeneous pool（3）Hydrolysis tank（4）A/O pool（5）Aeration tank（6）Electrochemical reaction\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Fig.1.png","url":"https://assets-eu.researchsquare.com/files/rs-4822048/v1/b294b2ead3d40311f1acc383.png"},{"id":63576011,"identity":"46b234a7-94f7-4d7e-8fd6-a556fd51decd","added_by":"auto","created_at":"2024-08-29 19:25:39","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":301644,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003e(a) SEM image of steel slag (b) EDS diagram of steel slag (c)X-ray diffraction patterns of Steel slag (d) VSM curves of steel slag\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Fig.2.png","url":"https://assets-eu.researchsquare.com/files/rs-4822048/v1/bd4b9529e2ac230390cb87e6.png"},{"id":63575748,"identity":"9e75e573-d983-421b-ab44-2b90d5cceb24","added_by":"auto","created_at":"2024-08-29 19:17:39","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":209526,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffect of different voltage conditions on the degradation of:(a) COD (b) TN ;Single factor optimization experiment results:(c)Voltage (d)Time (e) Water volume (f) Electrolyte\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Fig.3.png","url":"https://assets-eu.researchsquare.com/files/rs-4822048/v1/e4dde09cda37f206613e809d.png"},{"id":63575745,"identity":"fb324a0a-2266-46c5-9ced-90f4bb610e87","added_by":"auto","created_at":"2024-08-29 19:17:39","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":91718,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eEffect of different electrolyte concentrations on the degradation of TN\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Fig.4.png","url":"https://assets-eu.researchsquare.com/files/rs-4822048/v1/82693641ed290cb0a2b824bb.png"},{"id":63575749,"identity":"c34c6ec2-02f2-4b62-856c-7fbacc61cece","added_by":"auto","created_at":"2024-08-29 19:17:39","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":232138,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eResults of the different steel slag parameters optimization experiments: (a) (b) COD and (c) (d)TN\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Fig.5.png","url":"https://assets-eu.researchsquare.com/files/rs-4822048/v1/e5cade8409977d2382635c23.png"},{"id":63575750,"identity":"724a4f8f-34da-427c-a6a5-0045f27b8050","added_by":"auto","created_at":"2024-08-29 19:17:40","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":217004,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eReaction mechanism of three-dimensional electrochemical system\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"Fig.6.png","url":"https://assets-eu.researchsquare.com/files/rs-4822048/v1/2127d6bbe5b789ee6d015f83.png"},{"id":65007501,"identity":"cc580e6f-50ed-492a-a4ef-c9270dd5ab19","added_by":"auto","created_at":"2024-09-22 06:08:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1699461,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4822048/v1/87f2dbd6-dc6a-4ba7-8b2c-2cf60d6e7392.pdf"},{"id":63575744,"identity":"ea930d12-0f85-428a-856b-76c9154c9fcd","added_by":"auto","created_at":"2024-08-29 19:17:39","extension":"docx","order_by":10,"title":"","display":"","copyAsset":false,"role":"supplement","size":11892,"visible":true,"origin":"","legend":"","description":"","filename":"Highlights.docx","url":"https://assets-eu.researchsquare.com/files/rs-4822048/v1/a7708358985234205402ea3a.docx"}],"financialInterests":"","formattedTitle":"Superior Degradation characteristics of industrial wastewater treated by Biological and 3D Electrochemical Coupling Process","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eWith the rapid development of the social economy, the technology of industry has greatly improved, and it has indeed produced a lot of economic benefits. However, at the same time, industrial wastewater has increased exponentially, which has brought a huge burden on the environment and affected people's daily water quality as well. It is well known that the characteristics of industrial wastewater are mainly manifested in large discharge, complex composition and severe pollution. Therefore, there are great difficulties in treating industrial wastewater\u003csup\u003e1\u003c/sup\u003e. China's initial implementation of industrial wastewater treatment has achieved certain experience so far. The effectiveness of wastewater treatment capacity is obvious. It can meet a wide range of industrial wastewater treatment on the basis, but the treatment technology is still immature. In some small and medium-sized factories, in order to save money, the wastewater treatment process is simplified, and the sewage treatment is not done enough. After discharge, the surrounding water bodies and the environment will still be polluted. Therefore, developing techniques with low-energy consumption and high efficiency is urgently needed\u003csup\u003e2\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003ePollutants can be removed from wastewater using electrochemical treatment, and it is an environmentally friendly technology\u003csup\u003e3,4,5\u003c/sup\u003e.In particular, it has received more and more attention in environmental pollution control. Although electrochemical technology started late in China's sewage treatment, its development speed is extremely rapid\u003csup\u003e6\u003c/sup\u003e.It has been applied in many fields of environmental chemical engineering up to now\u003csup\u003e7\u003c/sup\u003e.This method exploits an electrochemical cell with a cathode and an anode that is leached in the effluent. The utilize of an electric current reasons redox reactions at the electrodes\u003csup\u003e8\u003c/sup\u003e.In the past a few years, the bio-electrochemical coupling process has emerged and develops fast since it can deeply treat wastewater\u003csup\u003e9,10\u003c/sup\u003e, and is widely used in the removal of pollutants in sewage due to its high efficiency, low consumption and relatively low cost. This technique is quite mature in western countries. In the past decade, some researches have been reported on the bio-electrochemical technology used to degrade pollutants in wastewater. For example, Ricardo A et al. used electrochemical-bio-coupling to treat industrial wastewater containing 5-amino-6-methyl-2-benzimidazolone and found that the pollutants can be removed effectively\u003csup\u003e11\u003c/sup\u003e.Yu et al designed a special centrifugal electrode reactor for the electrochemical treatment of wastewater including heavy metals. To make better the treatment of mimeticed heavy metal wastewater operating an aluminium anode\u003csup\u003e12\u003c/sup\u003e.Therefore, the research of electrochemical coupling technology in wastewater treatment is more and more important. In the meanwhile, the traditional 2D-electrochemical has some shortcomings, such as low effective current and small effective surface area, while three-dimensional electrochemical technology which means that additional component is added into the process can make up for these shortcomings\u003csup\u003e11\u003c/sup\u003e. Because of the many advantages of the three-dimensional (3-D) electrochemical oxidation reactor over the conventional electrochemical oxidation reactor, the 3D electrochemistry method has received much attention these days\u003csup\u003e13\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eMoreover, in recent years, the concept of \u0026ldquo;waste utilization\u0026rdquo; is highly valued in the field of water treatment\u003csup\u003e14,15,16\u003c/sup\u003e. Among them, Steel slag, a representative industrial waste, has been well utilized in some areas. For example, its good adsorption and sedimentation performance can remove pollutants from water and soil obviously\u003csup\u003e17,18\u003c/sup\u003e.The annual output of steel slag, a by-product of steelmaking in the world, is as high as 50\u0026nbsp;million tons\u003csup\u003e19,20\u003c/sup\u003e, and the number of steel slag that can be reasonably utilized in China is low and no more than 20%. Therefore, the rational use of steel slag is very urgent\u003csup\u003e21\u003c/sup\u003eAt present, the abundant metal resources have been neglected by the research process of steel slag, which leads to the great limitation of steel slag application in the field of water treatment. Studies have shown that the electro-Fenton process occurs in the three-dimensional electrode of steel slag because of the presence of Fe element, so it can effectively degrade organic matter\u003csup\u003e22,23,24\u003c/sup\u003e.In particular, some organic residues after secondary treatment of refinery wastewater are biologically toxic, and three-dimensional electrode technology can effectively select organic matter in the deep treatment process to better degrade organic matter\u003csup\u003e25\u003c/sup\u003e.In addition, the presence of Fe element makes the steel slag particles magnetic, which provides convenience for recycling of the technology.\u003c/p\u003e \u003cp\u003eBased on the above description, In the present work, the purpose of this study is to improve the treatment efficiency of secondary effluent by first using a biological process as the pretreatment of wastewater\u003csup\u003e26\u003c/sup\u003e and then combining with the three-dimensional electrode to form an electrochemical reaction to deeply treat the secondary effluent. We will choose the steel slag as a component of the particle electrode, which can better enhance the degradation efficiency of COD and TN mainly in the electrochemical reactor. It is expected that waste utilization of industrial waste can be effectively achieved while both reaction time and cost are reduced during the process.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Water quality characteristics\u003c/h2\u003e \u003cp\u003eThe raw water in this study is the drainage of the wastewater treatment plant in Lanzhou Petrochemical Company of Gansu in China. The raw water quality is shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The wastewater used in the electrochemical experiments was collected from wastewater in aeration tanks in the large-scale wastewater treatment facilities. Prior to the start of the electrochemical experiment, the water samples were stored in 20 L polyethylene drums in dark at 4℃ before use.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCharacteristics of Raw water quality\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eparameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNumerical range\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eaverage value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCOD(mg/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e423\u0026ndash;450\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e436.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTN(mg/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e48-47.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e47.95\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTP(mg/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.16\u0026ndash;3.43\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e3.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNH\u003csub\u003e3\u003c/sub\u003e-N(mg/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14.7\u0026ndash;15.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003epH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.78\u0026ndash;7.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7.81\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Experimental set-up\u003c/h2\u003e \u003cp\u003eDegradation experiments were performed in a lab-scale reactor as is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.Biological treatment device utilizes physical, chemical, physical and chemical methods, and adopts a combination of oil-repellent precipitation-homogeneous-hydrolysis acidification-A/O (anoxia/aerobic)-aeration process, through various treatment facilities and auxiliary facilities, mainly to remove pollutants from the petrochemical plant wastewater\u003csup\u003e27\u003c/sup\u003e.As shown in the electrochemical reaction part of Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.Set the electrochemical device as Test Device 1 and Test Device 2.The Test Device 1 was a static two dimensional system(no using steel slag).The Test Device 2 was a static three dimensional system. The static three dimensional device, which consists of 5L electrolytic cell, electrode plate, power supply, electric wire, industrial scrap slag, peristaltic pump, etc., and is electrolyzed by a single group of electrodes, wherein the anode plate is a titanium plate and the cathode is a DAS electrode plate.\u003c/p\u003e \u003cp\u003eSet the electrochemical device as Test Device 1 and Test Device 2. The Test Device 1 was a static two dimensional system. The Test Device 2 was a static three dimensional system.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Chemical and experimental equipment\u003c/h2\u003e \u003cp\u003eThis section only introduces the chemicals and experimental equipment used in the electrochemical experiment. The experimental drugs are divided into three categories according to the use conditions in the experimental process: the first type is the medicines required before the experiment, and is mainly used for the configuration of the standard stock solution; the second type is the medicines required during the experiment. For example, KCl is used as an electrolyte; the third type is a reagent used to analyze various water quality indicators at the end of the experiment. The chemicals used in the experiment are KCl, Ag\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e, HgSO\u003csub\u003e4\u003c/sub\u003e, K\u003csub\u003e2\u003c/sub\u003eCr\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e, NaOH, K\u003csub\u003e2\u003c/sub\u003eS\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e8\u003c/sub\u003e, H\u003csub\u003e2\u003c/sub\u003eSO\u003csub\u003e4\u003c/sub\u003e(98%), HCl, and the like. These chemicals were obtained from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). The chemical reagent is at least with analytical grade. It can be used without further purification. The solutions prepared in the experiments were all deionized water having a pH of 6.8.\u003c/p\u003e \u003cp\u003eThe instruments and equipment used in the experiment mainly include DC stabilized steady current power supply(KEYSIGHT.U8002A),ultrasonic cleaner(CNC.KQ3200DV,Kunshan,China), constant temperature drying oven, UV-visible spectrophotometer, COD digestion instrument(HASH.COD Reactor.WD325),COD rapid measuring instrument(ENOVI/NANNA), magnetic heating stirrer, and electronic equality. In addition, there are instruments and equipment commonly used in general laboratories.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Analytical method\u003c/h2\u003e \u003cp\u003eFirst add the effluent from the 2L aeration tank to the electrolytic cell with a volume of 5L, then add a certain proportion of KCl electrolyte, and stir evenly. A titanium plate and an DAS electrode plate having a surface area of 10 cm*1 cm were selected as the anode and the cathode, respectively, and the plate spacing was set to be not less than 15 cm. The two electrode plates are connected to the positive and negative electrodes of the direct current power source, respectively. In the experimental apparatus 2, the pretreated steel slag was filled in the bottom of the electrolytic cell in a certain ratio and the pH of the sewage was adjusted to 6.8\u0026ndash;7.5.When the experimental device is ready, turn on the power, select the appropriate voltage, and sample regularly to measure the water quality indicators. The steel slag used in the experiment was taken from the Yuzhong Iron and Steel Plant in Lanzhou, Gansu Province. Its appearance and composition are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThe COD in this experiment is measured by the rapid digestion spectrophotometry. (HJ/T 399\u0026ndash;2007) The measurement method of TN is alkaline potassium persulfate digestion ultraviolet spectrophotometry(HJ 636\u0026ndash;2012), the measurement method of NH\u003csub\u003e3\u003c/sub\u003e-N is Nessler reagent spectrophotometry(HJ 535\u0026ndash;2009), and the TP is measured with a molybdenum Acid spectrophotometry(GB 11893-89).\u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and discussion","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Water quality of effluent\u003c/h2\u003e \u003cp\u003eAfter the sewage from the chemical plant is treated by physical, chemical, biochemical and other processes, the effluent from the aeration tank is selected to test the pollutants. The water quality after biological treatment is shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCharacteristics of water quality\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eparameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGB value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBiological method\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eElectrochemistry2D\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eElectrochemistry3D\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCOD(mg/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.8\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTN(mg/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e21.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e17.32\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTP(mg/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.018\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNH\u003csub\u003e3\u003c/sub\u003e-N(mg/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003epH\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u0026ndash;9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e8.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.23\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAccording to the water quality of the secondary effluent, it is noticed that the four indicators basically meet the national first-class discharge standards for industrial wastewater, especially the content of TP and NH\u003csub\u003e3\u003c/sub\u003e-N has degraded to a very good condition. However, the content of COD and TN needs further eliminated,. The next step, we put focus on the degradation of COD and TN.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Steel slag electrode characterization\u003c/h2\u003e \u003cp\u003eIn order to study the surface morphology and crystal structure of steel slag, the slag was characterized by SEM, EDS, XRD and VSM.\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(a) shows the surface morphologies of the steel slag particle used in the experiment. It can be seen that the surface of the steel slag is mainly rugged and irregular, has high porosity. From the SEM image, it can be inferred that the diameters of the pores are micrometer range. High porosity helps to improve the adsorb-ability of the steel slag particle. The atomic percentage of all components that the steel slag particle are mainly contained can be showed on (b).from the (b) can be showed that atomic percentage of steel slag particle are mainly composed of O C Ca Mg and Fe. (c) shows the XRD pattern of the steel slag, the results show that the composition and crystal structure of steel slag are relatively complicated. By comparing the standard cards of the Joint Committee on Powder Diffraction Standards, it can be seen that the main elements are in the form of compounds. Oxygen, silicon, calcium are mainly in the form of crystalline quartz SiO\u003csub\u003e2\u003c/sub\u003e (JCPDS, 46e1045) and calcium silicate Ca\u003csub\u003e2\u003c/sub\u003eSiO\u003csub\u003e4\u003c/sub\u003e (JCPDS, 39e1346), ) exist in the Steel slag, and CaO (JCPDS, 28\u0026ndash;0775) can be seen on the XRD patterns too.Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e with crystalline phases of hematite (JCPDS, 33\u0026ndash;0664) and maghemite C (JCPDS, 39-1346), FeO with iron ore phases (JCPDS, 46-1312) and Fe\u003csub\u003e3\u003c/sub\u003eO\u003csub\u003e4\u003c/sub\u003e with cubic crystal phase (JCPDS, 65-3107) can be detected in the Steel slag. It can be indicated that steel slags have complex crystal structures. On the (d) can displayed the steel slag of magnetic characterization. In the light of (d),the steel slag particle is magnetic, and the hysteresis regression line presented uniformly symmetrical S-shaped curve. The saturation magnetic intensity of the steel slag particle are powerful. The magnetism of the steel slag particles would be momentous for recycle.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.3 Influence and optimization of operating parameters\u003c/h2\u003e \u003cdiv id=\"Sec11\" class=\"Section3\"\u003e \u003ch2\u003e3.3.1 Voltage effect\u003c/h2\u003e \u003cp\u003eExperimental conditions: The effective area of the cathode yin and anodeelectrode plates is 7.5 cm*1 cm. The electrode spacing was 17 mm, and 2000 mg/L of KCl was added as an electrolyte. The water quality is not adjusted during the reaction, and the effect of the treatment system on the secondary effluent is directly analyzed. Using the experimental device 1, the effect of COD and TN treatment was investigated by changing the voltage, and the effect of different voltages on the removal of pollutants in the actual sewage was compared. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(a) and (b)shows the results.\u003c/p\u003e \u003cp\u003eIt can be seen from the figure that as the voltage increases, the degradation efficiency of COD and TN also increases, and the content of COD and TN decreases overall. Therefore, it can be deduced that the increase in voltage is beneficial to the degradation of COD and TN. In order to determine the optimum voltage, the electrolysis time is set to 120 min. We extract the COD and TN values corresponding to each voltage from Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, the estimated degradation efficiency of COD and TN is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(c).\u003c/p\u003e \u003cp\u003eIt can be seen from the blue curve in the Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(c) that as the voltage increases, the degradation efficiency of COD also continues to increase. Increasing the voltages from 0 to 4, the degradation efficiency of COD increases obviously. When the voltage reaches 8V, the degradation rate can reach 91.03%.Continue to increase the voltage, there is almost no obvious change, so 8V is the saturated value for the optimal degradation efficiency of COD. The subsequent electrolysis experiment is then carried out at the voltage of 8v. The red curve in the figure shows the degradation effect of TN under different voltage conditions. It can be seen that when the voltage is increased to 8V, the degradation rate of TN can reach 27%. When the voltage is continuously increased to 10V, the removal rate of TN is decreased, which may be caused by an increase in voltage inducing an oxidation reaction during electrolysis, and finally results in an increase in the content of TN. Similarly, 8v is selected as the optimum voltage in combination with the removal state of the contaminant by the voltage.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003e3.3.2 time\u003c/h2\u003e \u003cp\u003eShown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(d).It is noted that when the voltage is constant, the degradation effect of COD and TN changes with time, and the elongation of electrolysis time causes the content of COD and TN to gradually decrease. When the electrolysis time reaches 120 minutes, the downward trend becomes slower. Even electrolysis continues, the COD removal is still within 5 mg/L, the TN removal is still within 20 mg/L. Therefore, it is meaningless to extend the electrolysis time.120 minutes is the best electrolysis time in the present study.\u003c/p\u003e \u003cp\u003eThe impact of the water quantity factor is also considered. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(e) shows the relationships of removing COD and duration with different amounts of water. It can be seen that the difference in water quantity under certain conditions will have a certain influence on the degradation rate of COD. When the amount of water treated is increased from 2L to 3.5L, the treatment effect tends to decrease. The removal rates differ by 15%-25% depending on the processing duration. Therefore, when the amount of water changes, it can be considered to increase the electrode group to ensure the treatment effect of the system on sewage.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section3\"\u003e \u003ch2\u003e3.3.3 Electrolyte effect\u003c/h2\u003e \u003cp\u003eIn this section, the effect of different electrolyte concentrations on the degradation rate of pollutants in water was observed. In this experiment, the electrolyte concentration was controlled in a range from 500mg/L to 5000mg/L. Six different concentrations were analyzed of 500mg/L,1000 mg/L ,2000mg/L, 3000mg/L, 4000mg/L and 5000mg/L to observe the degradation of COD and TN. The results are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(f), respectively.\u003c/p\u003e \u003cp\u003eThe blue curve in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(f) mainly examines the effect of different concentrations of electrolyte on the rate of COD degradation. It can be seen that the addition of Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e has a certain help to the degradation of COD. When the dosage of Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e reaches 2000mg/L, the degradation rate of COD can reach as high as 91.03%.\u003c/p\u003e \u003cp\u003eThe red curve in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(f) shows the effect of different electrolyte concentrations on the degradation rate of TN at a reaction time of 120 minutes and a voltage of 8 V. It can be seen from the figure that the dosage of electrolyte can effectively promote the degradation of TN, and the degradation rate changes with the change of electrolyte concentration. The main reason may be that Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e will produce active Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e with short life but with strong oxidative property during electrolysis. As the concentration of Cl increases, the degradation rate of TN increases significantly. The higher the concentration, the more obvious the tendency of the degradation rate to increase. When the dosage of Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e reaches 5000mg/L, the degradation rate of TN reaches 28.9%.It can be seen that Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e gradually undergoes electrolysis under electrochemical action, producing effective Cl, thereby increasing the removal of TN. The reaction process is as follows:\u003c/p\u003e \u003cp\u003eAnode: 2Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e\u0026rarr;Cl\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;2e (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eCathode:2H\u003csub\u003e2\u003c/sub\u003eO\u0026thinsp;+\u0026thinsp;2e\u003csup\u003e\u0026minus;\u003c/sup\u003e\u0026rarr;H\u003csub\u003e2\u003c/sub\u003e\u0026thinsp;+\u0026thinsp;2OH\u003csup\u003e\u0026minus;\u003c/sup\u003e (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eSolution:Cl\u003csup\u003e2\u003c/sup\u003e\u0026thinsp;+\u0026thinsp;H\u003csub\u003e2\u003c/sub\u003eO\u0026rarr;HClO\u0026thinsp;+\u0026thinsp;H\u003csup\u003e+\u003c/sup\u003e+Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eIt can be seen that Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e not only can rapidly generate substances with strong oxidizing properties such as Cl, but also can improve the conductivity in the solution. The current intensity through the electrodes in a unit time also increases, thus affecting the degradation of TN.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eBased on the comparison of the above various factors, Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e compares the degradation of TN at different concentrations. Although the electrolytes with a concentration of 5000mg/L has a better degradation effect on TN, the difference between these two is not particularly large. Therefore, in combination with the degradation rate of COD, in the three-dimensional electrode reaction experiment section, the optimum conditions were set: the electrolysis time is 120 minutes, and the voltage is 8V, the electrolyte concentration is 2000mg/L.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section3\"\u003e \u003ch2\u003e3.3.4 3D-electrode electrochemical reaction\u003c/h2\u003e \u003cp\u003eThrough the above experiments, it can be shown that the electrochemical system has certain effects on the advanced treatment of industrial wastewater, but the treatment effect of COD and TN is still limited. In order to further improve the treatment effect of sewage, combined with the experimental results of the previous progress, industrial waste steel slag\u003csup\u003e[11]\u003c/sup\u003e was added to the two-dimensional electrode reaction. A three-dimensional electrode system is then formed by the action of steel slag to enhance the overall treatment effect on sewage. Experimental conditions: The effective area of the yin and yang electrode plates is 7.5 cm*1 cm. The electrode spacing is 17 mm, the voltage is 8 V, reaction time is 120min, the electrolyte concentration is 2000mg/L. In this case, we use the experimental device 2.\u003c/p\u003e \u003cp\u003eThe results are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(a). As can be seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e,as the amount of steel slag increases, the COD content continuously decreases. Among them, when the amount of steel slag is added to be 30g, the degradation effect is the best. When the amount of steel slag is added to be 30g and keeps electrolysis for 120min,the degradation rate of COD can reach about 95.2%,and the degradation rate is increased by 5.8-6% at the same time compared with the two-dimensional system. In the three-dimensional system, the degradation efficiency of COD is about 92.2% when the electrolysis time is about 80 minutes, which exceeds the degradation effect in the two-dimensional system electrolyzed for 120 minutes. Therefore, it can be stated that the addition of steel slag can enhance the degradation of COD efficiently.\u003c/p\u003e \u003cp\u003eIt can be seen from Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(b) that the effect of the addition of steel slag on TN degradation is significantly higher than that without the addition. Among them, when the amount of steel slag added is 30g, the degradation effect is the best. When the amount of steel slag added is 30g, the content of TN is reduced to about 17.32mg/L with electrolyzed for 120min.Compared with the two-dimensional system, the content of TN decreases by about 4-4.2 mg/L, and the degradation rate increased by about 14.3%. Therefore, it can be proposed that the presence of steel slag in the three-dimensional system would promote the degradation of TN as well.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003e3.4 Mechanism of removal of COD and TN by 3D-electrode system\u003c/h2\u003e \u003cp\u003eFrom the experimental analysis, the main active substance involved in the degradation of COD and TN is HO\u0026bull;. The possible mechanism of the removal of COD and TN with a 3D-electrochemical system in shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e.In the removal process, pollutant molecules are adsorbed on the surface of the steel slag particle, and hydroxyl radicals are also generated in the boundary layer on the outer surface of the steel slag particle. The main pollutants with HO\u0026bull; on the surface of the steel slag particle. And a small amount of HO\u0026bull; diffused into the solution and continue to reacted. The addition of KCl causes Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e to undergo electrolysis under electrochemical action, producing effective Cl and accelerating the degradation of TN. Cl\u003csup\u003e\u0026minus;\u003c/sup\u003e not only rapidly generates strong oxidizing substances such as active chlorine, but also improves the electrical conductivity of the solution, so that the current intensity and current density increase, thereby accelerating the degradation of COD and TN.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003e3.5 Economic analysis\u003c/h2\u003e \u003cp\u003eThe cost of biological activated sludge process for advanced treatment wastewater in this experiment is negligible. The operating cost of the combined three-dimensional steel slag particle electrode electrochemical technology of the costs of electricity, reagents and material. which were 1.7, 0.01and 0.5 CNY/t respectively. The total operating cost was 2.2CNY/t.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eIn summary, 3D-electrochemical system were developed from steel slag, and the experimental conditions were optimized. The steel slag particles were characterized by SEM EDS XRD and VSM, and then were used in industrial wastewater advanced treatment in a designed 3D-electrochemical system. The steel slag particles were used in 3-D system for COD and TN degradation, and exhibited high catalytic activity by increasing hydroxyl radicals in the system. The results show that the degradation rate of COD and TN in 3D-electrochemical system with steel slag particle is significantly higher than that of 2D-electrochemical system. It can be seen from the results that the 3D-electrochemical coupling can greatly improve the degradation efficiency of pollutants in the sewage. In particular, the treatment effect of COD is very promising and meets the requirements of water quality. Moreover, in view of economic analysis, it can be seen that the cost of processing water per ton is 2.2CNY/t, which meets the requirements of low energy consumption.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eConflicts of interest\u003c/h2\u003e \u003cp\u003eThere are no conflicts to declare.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAcknowledgments\u003c/h2\u003e \u003cp\u003eThe Gansu Provincial Science and Technology Major Program (21ZD4GD033), the Gansu Provincial Key R\u0026amp;D Projects (22YF7GD194), the Gansu Provincial Science and Technology Program (22ZY1QD001).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eK.Zhe, L.Lu, X.Yi, Y.Min, Yu-You Li, Journal of Cleaner Production, 2019,231,913\u0026ndash;927.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAmishi Popat, P.V. Nidheesh, T.S. Anantha Singh, M. 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Chen,Separation and Purification Technology, 2020,237,116321.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Bio-electrochemical coupling, Industrial waste, Advanced processing,3D-electrolysis","lastPublishedDoi":"10.21203/rs.3.rs-4822048/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4822048/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe performance of the combined biological and three-dimensional electrochemical treatments was studied for the industrial wastewater from sewage treatment plant. The process parameters were investigated.Result showed that the system could remove over 99.13% COD,63.88% TN,99.42% TP and 25.0% NH\u003csub\u003e3\u003c/sub\u003e-N in 2h. Under the operating conditions of voltage 8V, electrolysis 120min, addition of 2000mg/L electrolyte KCl and 30g industrial waste steel slag, the degradation of pollutants is effectively improved. And through economic analysis, it can be calculated that it only costs 2.2CNY/t to process one ton of industrial wastewater. The experimental results not only meet the water discharge standards, but also pave the way for developing techniques with high efficiency, economy, low energy consumption and universal use.\u003c/p\u003e","manuscriptTitle":"Superior Degradation characteristics of industrial wastewater treated by Biological and 3D Electrochemical Coupling Process","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-29 19:17:34","doi":"10.21203/rs.3.rs-4822048/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"33c37755-ba67-43e9-846e-95783ec7270b","owner":[],"postedDate":"August 29th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-09-22T05:43:53+00:00","versionOfRecord":[],"versionCreatedAt":"2024-08-29 19:17:34","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4822048","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4822048","identity":"rs-4822048","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}