Ozonation Process Research Articles

Combination of CFD and machine learning for improving simulation accuracy in water purification process via porous membranes

Membrane system for molecular separation was studied in this work using combined modeling approach. Computational fluid dynamics (CFD) was conducted and integrated to machine learning models for description of ozonation process in membrane contactors. For the machine learning modeling, we investigated the performance of boosted models, specifically AdaBoost KNN, AdaBoost DT, and AdaBoost ARD, for predicting the concentration (C) of ozone using the input variables, i.e., r and z. The hyper-parameter optimization is done using Successive Halving in this study. The results reveal that AdaBoost KNN achieves the highest performance among the three models, with an impressive R2 score of 0.9992. This indicates an excellent fit of the model to the data, implying that approximately 99.92% of the variance in the concentration can be explained by the input variables r and z. Moreover, AdaBoost KNN demonstrates a low RMSE of 1.5695E-02, indicating its ability to provide accurate predictions with small deviations from the actual values. The maximum error of 1.02733E-01 further confirms the model's robustness, as it represents the largest deviation between predicted and CFD values, which is relatively small.

Ozonation Processes for Color Removal from Urban and Leather Tanning Wastewater

The need to ensure adequate levels of both human and environmental health protection calls for the identification of efficient wastewater treatment processes that target the removal of conventional pollutants as well as emerging contaminants, including synthetic dyes. This study explores the potential of ozone for use in the decolorization of both pretreated tannery wastewater and urban wastewater effluents. Different ozone contact times (15, 30, and 45 min) were applied to such wastewater samples at an uncontrolled (7.5–8.2) pH as well as at a pH adjusted to 10. The highest color removal efficiencies (REs) (>90%) were obtained with urban wastewater after a 45 min contact time and at pH 10. Under the same conditions, a COD RE from 31 to 51% was achieved. Even without pH adjustment, color and COD REs ranging from 81 to 92% and 39 to 41%, respectively, were obtained. A preliminary evaluation of the costs associated with the implementation of an ozonation stage within the wastewater treatment plant (WWTP) generating the urban wastewater used here was carried out. The energy cost of the ozone treatment would account for a 69% increase in the total energy cost of the WWTP, suggesting the need to identify proper strategies to enhance the cost-competitiveness of this technology.

Performance of alkali and Cu-modified ZSM-5 during catalytic ozonation of polyvinyl alcohol in aqueous solution.

A novel hierarchical Cu/ZSM-5 was prepared over alkaline treatment and incipient wet impregnation method for the catalytic ozonation of polyvinyl alcohol (PVA). Under the optimum preparation conditions, hierarchical Cu/ZSM-5 exhibited an excellent mineralization performance during the PVA degradation process, and the removal rate of TOC after 60min of reaction was 47.86%, much higher than that of ozonation alone (5.40%). Its high catalytic activity could attribute to the large pore volume (0.27 cm3/g) and pore size (6.51nm) which are beneficial for the distribution of loaded copper and adsorption performance for PVA. Compared to ·OH, 1O2 (2.66 times in 10min) contributed more to the removal of PVA. The degradation of PVA was a combined process of direct ozone oxidation, catalytic ozonation and adsorption. With its high catalytic performance and stability, hierarchical Cu/ZSM-5 has a very broad application prospect in the process of catalytic ozonation of refractory pollutants.

Inhibition of bromate formation in plasmon-enhanced catalytic ozonation over silver-doped spinel ferrite

High energy consumption and formation of harmful byproducts are two challenges faced by advanced oxidation processes (AOPs). While much research efforts have been devoted to improving the treatment efficiency, byproduct formation and control calls for more attention. In this study, the underlying mechanism of bromate formation inhibition during a novel plasmon-enhanced catalytic ozonation process with silver-doped spinel ferrite (0.5wt%Ag/MnFe2O4) as the catalysts was investigated. By scrutinizing the effects of each factor (i.e. irradiation, catalyst, ozone) as well as the combinations of different factors on major Br species involved in bromate formation, examining the distribution of Br species, and probing the reactive oxygen species partaking in the reactions, it was found that accelerated ozone decomposition which inhibited two main bromate formation pathways and surface reduction of Br species (e.g. HOBr/OBr− and BrO3−) contributed to the inhibition of bromate formation, both of which can be enhanced by the plasmonic effects of Ag and the good affinity between Ag and Br. A kinetic model was developed by simultaneously solving 95 reactions to predict the aqueous concentrations of Br species during different ozonation processes. The good agreement between the model prediction and experimental data further corroborated the hypothesized reaction mechanism.

Research of the Process of Ozonation and Sorption Filtration of Natural and Anthropogenicly Pollated Waters

This scientific research work is written based on the problem of studying the process of ozonation and sorption filtration of natural and anthropogenically polluted waters. Scientific research work of our country is diverse It was prepared in the laboratory of water ozonation, and purification technology and equipment of Kazakh National Research Technical University named after K. I. Satbayev based on long-term research conducted in cities and regions. The current state of ozonation equipment and active carbon production is considered in the research work. The scientific research work is intended to solve problems and tasks related to the use of ozonation and sorption water purification methods for employees of the sector of quality water supply and water treatment. In addition, the research work is devoted to the problems of water purification using ozone. Provides general information about the properties of ozone, its interaction with inorganic and organic compounds. The main methods of obtaining ozone, the effect of design parameters on the efficiency of ozonators are shown. The main domestic and foreign manufacturers of ozonation equipment are presented. In the research paper, considering the effectiveness of removing various organic and inorganic pollutants of natural and anthropogenic origin, microbiological pollutants, the authors' long-term research on purification and disinfection of natural waters are systematized. Production experience of using ozone in foreign and Kazakh water facilities, as well as in local water treatment plants is presented.

Catalytic ozonation process using modified activated carbon as a cataly s t for the removal of sarafloxacin antibiotic from aqueous solutions

Sarafloxacin (SAR) is an antibiotic from the fluoroquinolone group and is also one of the most widely used antibiotics in veterinary medicine. Potential performance and appropriate effectiveness have made SAR a special place among antibiotics. Antibiotic residues in the environment cause many problems, the most important of which is antibiotic resistance. Therefore, it is necessary to remove antibiotic residues from the environment. Response surface methodology (RSM) was utilized as a mathematics and statistics approach to optimize the removal efficiency of SAR using the catalytic ozonation process. The obtained regression equation for the response was the quadratic mathematical model. The coefficient of determination (R2), adjusted R2, and predicted R2 were obtained at 0.9939, 0.9917, and 0.9855, respectively. The maximum removal efficiency of 99.3% was obtained under optimum conditions, including a SAR concentration of 30.0 mg L-1, ozone dose of 1.5 mg min-1, catalyst dose (modified activated carbon) of 600 mg L-1, pH of 5.0, and reaction time of 30 min. According to the obtained results, the catalytic ozonation process as a suitable technique can efficiently remove SAR and other pharmaceutical compounds.

Degradation of Methylene Blue Dye in Wastewater Using Ozonation Method with H2O2 Catalyst

Water pollution is still a serious problem in Indonesia. One of the pollutants that contribute to water pollution is dye. One type of dye that is often used in the textile industry is methylene blue. There are several methods for treating dye waste, one of which is the ozonation method. Ozonation is a chemical oxidation process to remove the color of organic dyes. The catalytic ozonation process can increase the ability of ozone in sewage treatment. The catalyst used is H2O2 which can decompose into OH radicals. OH radicals have a higher reduction potential than other oxidizing agents. Ozonation research with H2O2 catalyst aims to determine changes in the concentration of dyes, COD and BOD5. In testing the ozonation time (0.15,30,45,60) minutes, the pH conditions (5,7,9) and the total mass concentration of H2O2 (0.2,5,5,7,5,10) % showed that the longer the time ozonation, the higher the pH value. and the more H2O2 used, the less concentration of dye, COD and BOD5.

Evaluation of the role of superoxide radical as chain carrier for the formation of hydroxyl radical during ozonation

Superoxide radicals (O2•−) have been suggested as an important chain carrier in the radical chain reaction that promotes ozone (O3) decomposition to hydroxyl radicals (•OH) during ozonation. However, due to the difficulty in measuring transient O2•− concentrations, this hypothesis has not been verified under realistic ozonation conditions during water treatment. In this study, a probe compound was used in combination with kinetic modeling to evaluate the role of O2•− for O3 decomposition during ozonation of synthetic solutions with model promotors and inhibitors (methanol and acetate or tert-butanol) and natural waters (one groundwater and two surface waters). By measurement of the abatement of spiked tetrachloromethane (as a O2•− probe), the O2•− exposure during ozonation was determined. Based on the measured O2•− exposures, the relative contribution of O2•− to O3 decomposition, in comparison to OH−, •OH, and dissolved organic matter (DOM), was quantitatively evaluated using kinetic modeling. The results show that water compositions (e.g., the concentration of promotors and inhibitors, and the O3 reactivity of DOM) have a considerable effect on the extent of the O2•−-promoted radical chain reaction during ozonation. In general, the reaction with O2•− accounted for ∼59‒70% and ∼45‒52% of the overall O3 decomposition during ozonation of the selected synthetic solutions and natural waters, respectively. This confirms that O2•− plays a critical role in promoting O3 decomposition to •OH. Overall, this study provides new insights on the controlling factors for ozone stability during ozonation processes.

The effect of nitrous acid (HONO) on ozone formation during pollution episodes in southeastern China: Results from model improvement and mechanism insights

Two ozone (O3) processes, summer episode dominated by local production and autumn episode dominated by regional transport, were chosen to investigate the role of HONO in different pollution processes. Meteorological conditions, diurnal variation of O3, potential source contribution factor (PSCF) analysis, concentration weighted trajectory (CWT) models, and the distribution of the eight-hour maximum values of O3 on mainland China all prove that summer O3 was mainly locally generated while autumn O3 episode was more susceptible to regional transport. The gaps between observations and simulation results with the default HONO chemistry in Master Chemical Mechanism (MCM) of Observation Based Model (OBM) were higher in summer episode (0.58 ppb) than autumn episode (0.37 ppb). Although we implemented nine additional sources in the model to revise the HONO chemistry, the simulated values were still lower than the observed values. HONO promoted O3 production by accelerating the reaction of HO2 + NO and RO2 + NO, and promoted loss of O3 by the reaction of OH + NO2 and RO2 + NO2. The net production rate of O3 with HONO constraint increased by 28.50 % in summer and 22.43 % in autumn, which also indicated that HONO played more important role in the O3 production in summer. The difference of NOx of daily RIR between the cases with and without HONO constraint was higher in summer O3 episode (0.15 %/%) than that in autumn O3 episode (0.09 %/%), the same as to VOCs with −0.20 %/% in summer O3 episode and − 0.14 %/% in autumn O3 episode, which indicated that the presence or absence of the HONO constraint has a greater impact on the RIR value in the case of dominant local generation. In brief, the O3 sensitivity would be more favorable for VOCs without HONO constrained in the model, which would inevitably mislead policy makers to develop efficient policies to control O3 pollution.

Ozonation-pelleting of nitrogen-enriched wheat straw: Towards improved pellet properties, enhanced digestibility, and reduced methane emissions

The livestock industry needs to use crop straws that are highly digestible to improve feed productivity and reduce ruminal methane emissions. Hence, this study aimed to use the ozonation and pelleting processes to enhance the digestibility and reduce the ruminal methane emissions of wheat straw enriched with two nitrogen sources (i.e., urea and heat-processed broiler litter). Various analyses were conducted on the pellets, including digestibility indicators, mechanical properties, surface chemistry functionalization, chemical-spectral-structural features, and energy requirements. For comparison, loose forms of the samples were also analyzed. The nitrogen-enriched ozonated wheat straw pellets had 43.06 % lower lignin, 28.30 % higher gas production for 24 h, 12.28 % higher metabolizable energy, 13.78 % higher in vitro organic matter digestibility for 24 h, and 28.81 % higher short-chain fatty acid content than the nitrogen-enriched loose sample. The reduction of methane emissions by rumen microorganisms of nitrogen-enriched wheat straw by ozonation, pelleting, and ozonation-pelleting totaled 89.15 %, 23.35 %, and 66.98 %, respectively. The ozonation process resulted in a 64 % increase in the particle density, a 5.5-time increase in the tensile strength, and a 75 % increase in the crushing energy of nitrogen-enriched wheat straw. In addition, ozone treatment could also reduce the specific and thermal energy consumption required in the pelleting process by 15.10 % and 7.61 %, respectively.

Ozone Processing of Corn Grains: Effect on Seed Vigor and Surface Disinfection

ABSTRACT Ozone treatment of corn seeds with respect to determination on changes in germination ability, germination under salt stress, seedling growth, seedling root length, conductivity and inactivation of endogenous microflora was studied. Corn seeds immersed in water treated by fixed ozone dose of 12.5 g/m3 for 1 (1O3), 3 (2O3) and 5 min (3O3) at room temperature. Ozone treatment provided full germination (100%) of the corn seeds on the 2nd day; whereas 66.6% of the control seeds germinated on the 8th days after planting. Ozone treated seedling were significantly taller and stronger than the control samples with significantly longer seedling root. Germination under 100 mM salt stress for ozone treated seeds was significantly higher than that of the control samples. Electrical conductivity of the seeds was significantly affected by the measurement time rather than ozone treatments. Ozone treatments provided significant inactivation on total aerobic mesophilic bacteria and total mold and yeast of the endogenous bacteria revealing maximum of 5.31 and 6.15 log reductions, respectively. It was concluded that ozone treatment at 12.5 g/m3 for 5 min can be utilized to treat corn seeds as these treatment parameters provided maximum inactivation on endogenous microflora with improvement of vigor and stronger seedling formation.

Evaluation of Heterogeneous Catalytic Ozonation Process for the Removal of Micropollutants from Water/Wastewater: Application of a Novel Pilot-Scale Continuous Flow System

The present study evaluates the removal of micropollutants from water/wastewater contaminated sources through the application of a heterogeneous catalytic ozonation process, using a pilot-scale continuous operation unit, composed of a membrane module for the diffusion and effective dilution of ozone into the liquid phase to be treated and a plug flow reactor/continuous stirred tank reactor (PFR/CSTR) contact reactor system in series, where the catalyst is recirculated in dispersion mode. The solid materials tested as catalysts are natural and calcined zeolite, Bayoxide and alumina, whereas the examined micropollutants, used in this case as probe compounds, are p-chlorobenzoic acid (p-CBA), atrazine, benzotriazole and carbamazepine. A high-performance liquid chromatography system was used to determine the removal of micropollutants. In the case of p-CBA, an ozone-resistant compound, the addition of catalyst was found to significantly enhance its degradation rate, leading to >99% removal under the optimum defined conditions, i.e., in terms of catalyst concentration, pH, temperature, and process time. On the other hand, in the case of atrazine, a different ozone-resistant compound, the introduction of examined catalysts in the ozonation process was found to reduce the degradation of micropollutant, when compared with the application of single ozonation, indicating the importance of specific affinity between the pollutant and the solid material used as catalyst. Benzotriazole, a moderately ozone-reactive compound was degraded by more than 95% under all experimental conditions and catalysts tested in the pilot unit, while carbamazepine, a highly ozone-reactive compound, was completely removed even during the first stage of treatment process (i.e., at the membrane contactor). When increasing the pH value (in the range 6–8) and the contact time, the performance of catalytic ozonation process also improved.

Coupling ozonation with hydrogen peroxide and chemically enhanced primary treatment for advanced treatment of grey water

Grey water is a valuable water source due to its high-volume generation. This study was conducted with grey water that was obtained from a hotel with 1000 inhabitants and average flowrate of 40 m3/day. The main objective of the study was to determine the optimum operational conditions for ozonation process in terms of micropollutant removal along with conventional parameters and to enhance the removal efficiency of ozonation process by coupling with hydrogen peroxide or chemically enhanced primary treatment (CEPT) process. The results indicated that the COD removal efficiencies were around 37% by both sole ozonation and peroxone processes. However, CEPT+ozonation process increased the COD removal efficiency to 71%. On the other hand, TSS removal efficiency by peroxone and CEPT+ozonation processes were 57% and 89%, while TP removal efficiencies were 26% and 74%, respectively. All micropollutants that were detected in grey water, were removed until the limit of detection (LOQ) with all treatment processes. Overall evaluation of the results indicated that CEPT combined with the ozonation process was more effective in terms of removal of conventional parameters compared to sole ozonation and peroxone processes. Therefore, CEPT+ozonation process with the optimum ozone dosage and contact time is recommended to increase the possibility to reuse the treated grey water. A feasibility analysis was conducted for optimum ozonation mode and CEPT+ozonation, and the results revealed that unit total cost and unit operational cost for ozonation system was 0.027 $/m3 and 0.01 $/m3, respectively. The unit operational cost for CEPT+ozonation system was 0.124 $/m3.

Numerical simulation of ozonation in hollow-fiber membranes for wastewater treatment

In this study, we developed a comprehensive modeling framework for simulation of ozonation process using combination of artificial intelligence and computational fluid dynamics (CFD). The process is carried out in a hollow-fiber membrane contactor in which the concentration data of ozone was obtained by solution of mass transfer equations, and then the results were used for artificial intelligence modeling. We used three different machine learning models to predict concentration of ozone (C) in a system based on its coordinates, i.e., r and z. The models were optimized using the Bat Algorithm (BA) and were trained on a dataset consisting of over 10,000 data points. The three models developed were Support Vector Regression (SVR), Decision Tree Regressor, and Orthogonal Matching Pursuit (OMP). These models were evaluated using three common metrics — Mean Squared Error (MSE), R-squared (R2), and Mean Absolute Error (MAE). Our results indicated that the SVR model overperformed the other two models in terms of all evaluation metrics. Specifically, the SVR model achieved an MSE of 0.003, an R2 of 0.998, and an MAE of 0.046. The Decision Tree Regressor and OMP models achieved less favorable results with MSEs of 0.007 and 0.221, R2 scores of 0.996 and 0.878, and MAEs of 0.056 and 0.359, respectively.

Exploration of surface hydroxyl on goethite during heterogeneous catalytic ozonation process: Generation, category, charged property, and contribution

The surface hydroxyl of a catalyst is believed to play a crucial role in O3 decomposition during heterogeneous catalytic ozonation. However, studies related to the generation, category, charged properties and the respective contributions of surface hydroxyl are inadequate. In this study, a hydroxyl-rich goethite (α-FeOOH) was selected as the catalyst for the ozonation of ibuprofen (IBP). By heating the catalyst and changing the reaction pH, the state of the hydroxyl groups on the catalyst surface was successfully adjusted, and the main functional hydroxyl group for ozone catalysis was identified. The results indicated that the addition of α-FeOOH during ozonation effectively degraded and mineralized IBP, and the main action was to promote the decomposition of O3 into •OH. Thermogravimetry and X-ray photoelectron spectroscopy (XPS) analyses showed that four types of hydroxyl groups coexisted on the surface of the catalyst. While adsorbed hydroxyl presented the least, the vacancy, metal, and basic site hydroxyls were dominant. Fourier transform infrared spectroscopy (FTIR) and XPS analyses revealed that heating the catalyst to 350 °C could eliminate the vacancy hydroxyl, whereas the metal and basic site hydroxyls recovered to their before-heating levels, which is related to the crystal transformation of the catalyst from goethite to hematite. Changing the solution pH from 3.0 to 9.0 adjusted the surface hydroxyl charge from positive to negative, and the neutral vacancy hydroxyl was judged as the main functional hydroxyl for ozone catalysis. Finally, a route involving the decomposition of O3 into •OH on the surface hydroxyl is proposed.

Oxidative power loss control in ozonation: Nanobubble and ultrasonic cavitation

Nanobubble and ultrasonic cavitation were applied to support and prolong oxidation reactions of ozonation. Nanobubbles increased ozone dissolution by a factor of 16 due to low buoyancy, high surface area, and stability in water. Hydroxyl radicals generated by ultrasonic cavitation produced hydrogen peroxide rather than recombining due to additional oxygen atoms supplied by the nanobubbles. The generated hydrogen peroxide formed hydroperoxyl ions that reacted with ozone to generate hydroxyl radicals. The process achieved improvements in both the loss of emitted ozone and radical recombination. Rhodamine B decomposition was used to gauge the effectiveness of the process, with the highest rhodamine B decomposition evident at a high initial pH and power and a frequency of 132 kHz as revealed in ultrasonic experiments. The process achieved more than 99% of the rhodamine B decomposition in 20 min under the most efficient conditions. The generation of hydrogen peroxide exhibited tendencies similar to those of rhodamine B decomposition, supporting the proposed mechanism. An ozonation process combined with nanobubble and ultrasonic cavitation can therefore sustain oxidizing power using continuous dissolution by nanobubbles and successive radical generation caused by hydrogen peroxide generated by cavitation.

Technical and economical assessment of the treatment of vinasse from Pisco production using the advanced oxidation process.

The removal of organic matter from Pisco production wastewater was evaluated using coagulation/flocculation, filtration as a pre-treatment, and solar photo-Fenton, with the use of two types of photoreactors: compound parabolic collectors (CPC) and flat plate (FP), with and without utilizing the ozonation process. The overall removal efficiency for chemical oxygen demand (COD) was 63% and 15% using FP and CPC, respectively. Also, for the overall removal efficiency of polyphenols, a percentage of 73% and 43% were obtained using FP and CPC, respectively. When ozone was used in the solar photoreactors, the resulting trends were similar. COD and polyphenol removal, using an FP photoreactor in the solar photo-Fenton/O3 process, resulted in values of 98.8% and 86.2% after the process. COD and polyphenol removal, using solar photo-Fenton/O3 process in a CPC, resulted in values of 49.5% and 72.4%, respectively. The economic indicators of annual worth and economic treatment capacity established that FP reactors represent lower costs than CPCs. These results were corroborated by the economic analyses of the evolution of costs versus COD removed as well as by the cash flow diagrams projected for 5, 10, and 15years.

Theoretical study on the degradation mechanism, kinetics and toxicity for aqueous ozonation reaction of furan derivatives

The compounds including furan-2,5-dicarboxylic acid (FDCA), 2-methyl-3-furoic acid (MFA), and 2-furoic acid (FA), containing Furan ring are considered to be possessing high ozone reactivity, although in depth studies of their ozonation processes have not been carried out yet. Hence, mechanism, kinetics and toxicity by quantum chemical, and their structure activity relationship are being investigated in this study. Studies of reaction mechanisms revealed that during the ozonolysis of three furan derivatives containing C=C double bond, furan ring opening occurs. At temperature (298 K) and pressure of 1 atm, the degradations rates of 2.22 × 103 M−1 s−1 (FDCA), 5.81 × 106 M−1 s−1 (MFA) and 1.22 × 105 M−1 s−1 (FA) suggested that the reactivity order is: MFA > FA > FDCA. In the presence of water, oxygen and ozone, the Criegee intermediates (CIs) as the primary products of ozonation would produce lower molecule weight of aldehydes and carboxylic acids by undergoing degradation pathways. The aquatic toxicity reveals that three furan derivatives play green chemicals roles. Significantly, most of the degradation products are least harmful to organisms residing in the hydrosphere. The mutagenicity and developmental toxicity of FDCA is minimum as compared to FA and MFA, which shows the applicability of FDCA in a wider and broader field. Results of this study reveal its importance in the industrial sector and degradation experiments.

Synthesis of δ-MnO2 via ozonation routine for low temperature formaldehyde removal

Nowadays, it is still a challenge to prepared high efficiency and low cost formaldehyde (HCHO) removal catalysts in order to tackle the long-living indoor air pollution. Herein, δ-MnO2 is successfully synthesized by a facile ozonation strategy, where Mn2+ is oxidized by ozone (O3) bubble in an alkaline solution. It presents one of the best catalytic properties with a low 100% conversion temperature of 85°C for 50 ppm of HCHO under a GHSV of 48,000 mL/(g·hr). As a comparison, more than 6 times far longer oxidation time is needed if O3 is replaced by O2. Characterizations show that ozonation process generates a different intermediate of tetragonal β-HMnO2, which would favor the quick transformation into the final product δ-MnO2, as compared with the relatively more thermodynamically stable monoclinic γ-HMnO2 in the O2 process. Finally, HCHO is found to be decomposed into CO2 via formate, dioxymethylene and carbonate species as identified by room temperature in-situ diffuse reflectance infrared fourier transform spectroscopy. All these results show great potency of this facile ozonation routine for the highly active δ-MnO2 synthesis in order to remove the HCHO contamination.

Effect of the deposition of Ca2+on the Fe-based catalyst in the catalytic ozonation of high-salinity wastewater

Fe-based catalysts used for catalytic ozonation process (COP) were widely investigated. However, there was almost no research on engineering application of Fe-based catalyst for advanced treatment of high-salinity pharmaceutical wastewater. In this study, Fe shavings were used to form Fe-based monolithic catalyst packing, which was effectively applied to a pharmaceutical factory. It was found that chemical oxygen demand (COD) removal decreased by ∼ 20% after more than three years of operations. Regression analysis showed that ozone (O3) dosage and hydraulic residence time (HRT) had significant impact on the catalytic performance. The characterization results of Fe-based catalyst demonstrated that calcium carbonate (CaCO3) was deposited on the surface of the Fe-based catalyst inside the packing, and partial γ-FeOOH were converted into α-FeOOH. These phenomena impaired the catalytic capacity of Fe-based catalyst and further reduced the production of hydroxyl radicals (OH). Besides, the increase in bulk density of Fe-based monolithic catalyst packing indicated that the packing has collapsed. By comparing the surface film properties of Fe-based catalyst in wastewater with different salinity, it was concluded that high-salinity wastewater would accelerate the corrosion of Fe-based catalyst. This study can provide a reference for the engineering application of catalytic ozonation technology in high-salinity wastewater.