Ozone Dose Research Articles

Ozonation enables to suppress horizontal transfer of antibiotic resistance genes in microbial communities during swine manure composting

Although aerobic composting process has been proposed as an efficient approach to treat livestock manure, the evolution patterns of extracellular antibiotic resistance genes (eARGs) and intracellular antibiotic resistance genes (iARGs) and their horizontal transfer during composting are unclear. Here, the variations of iARGs and eARGs during swine manure composting were systematically analyzed. We found that the abundance of ARGs rebounded from thermophilic phase to mature phase. This was due to the release of persistent eARGs and the increase of certain iARGs during cell proliferation. The conjugative transfer frequencies of ARGs in composting communities were (1.68 ± 0.2) × 10-1 Transconjugant/Donor + Recipient (TC/D + R) in composting products, which was comparable to the frequency before the composting. Ozone was then optimized to suppress the rebound and spread of ARGs. We found that the low ozone dosage of 0.4 g/kg FW in the cooling phase could not only significantly remove iARGs (2.02-logs less than the control, 8 of 12 targeted iARGs were not detected) by eliminating the potential hosts, but also decrease the possibilities of both conjugation and transformation among the composting products by eliminating both HGT (conjugation and transformation) efficiencies of microbes and microbes themselves. Collectively, this study proposes the optimal ozonation strategy to mitigate the dissemination of ARGs in the composting products.

Facile-prepared Fe/Mn co-doped biochar is an efficient catalyst for mediating the degradation of aqueous ibuprofen via catalytic ozonation

The fabrication of efficient, stable, and low-cost catalysts is crucially important for the catalytic ozonation process for the removal of recalcitrant pollutants. In this study, we present a facile impregnation-pyrolysis method for the preparation of novel porous Fe/Mn co-doped biochar (Fe-Mn-C) with excellent catalytic activity and reusability for the catalytic ozonation of ibuprofen (IBP). The incorporation of Fe/Mn heteroatoms into the carbon skeleton of biochar not only produced more defective sites and promoted the charge transfer on the materials surface but also created active Fe/Mn species with multi-valence states for ozone activation. As a result, >95% of IBP (50 mg/L) and 80.5% of total organic carbon can be rapidly removed within 9 min in the Fe-Mn-C/O3 process at a pH of 7, ozone dosage of 4.93 mg/min, and Fe-Mn-C dosage of 0.5 g/L. The catalytic reaction rate in Fe-Mn-C/O3 was 6.58 times higher than that of sole ozonation and 2.3–4.1 times higher than that of catalytic ozonation with other catalysts (e.g., biochar, Fe-doped biochar, Mn-doped biochar, activated carbon, Fe3O4 and MnO2). Moreover, the obtained Fe-Mn-C can be reused for multiple cycles; the performance is not significantly reduced in subsequent cycles, and there is no significant metal leaching. Further studies suggested that the radical pathways (superoxide radicals and hydroxyl radicals) were mainly responsible for the degradation of IBP in the Fe-Mn-C/O3 system. Furthermore, the contributions of the surface functional groups, doped atoms, and delocalized π electrons of Fe-Mn-C to the decomposition of ozone and the formation of reactive species were identified by correlation analysis between the catalytic ozonation rate and the physiochemical properties of Fe-Mn-C to clarify the mechanism underlying the improved performance.

Ozonation for oxidation and transformation of pharmaceuticals in Arroio Diluvio River in Southern Brazil

ABSTRACT Pharmaceuticals are often found in the water environment and are not completely degraded by conventional treatment processes. There are some techniques, such as advanced oxidative processes (AOPs), which can promote, in addition to the total removal of contaminants, their mineralization, transforming them into CO2 and water. Thus, the objective of this work was to evaluate the mineralization capacity of the emerging pollutants caffeine and ampicillin, present in a real aqueous matrix, through ozonation. Factorial planning was carried out by Central Composite Design (CCD) under the Response Surface Methodology (RSM). Water samples were collected from Arroio Dilúvio, a river that cuts through the city of Porto Alegre (RS – Brazil), which receives domestic, hospital, and industrial effluents in nature. The experiments were conducted from the analysis of the influence of pH, time, and ozone flow rate variables. The ozonation system consisted of an oxygen concentrator, an ozone generator, and a gas washer bottle. With removals of caffeine and ampicillin around 100 and 99.7%, respectively, a mineralization of 30.8% was also obtained under conditions of pH 8, with an applied ozone dosage of 830 mg.L−1. In this process, the gas phase concentration was at 16.7 mg.L−1 when applied to 200 mL sample for 10 minutes and ozone flow rate of 1 L.min−1. A linear relationship was observed between the real and predicted values, and it has been shown that the relationship of the residual plot confirmed a sufficient approximation of the method for the optimization process. Finally, the desirability function showed adequate operating conditions for the mineralization of compounds by ozonation. Therefore, it is considered that this technique is effective for the mineralization of the pharmaceuticals studied, and can be applied as a way of treating a contaminated real matrix.

Formation of carbonyl compounds during ozonation of lake water and wastewater: Development of a non-target screening method and quantification of target compounds

Ozonation of natural waters is typically associated with the formation of carbonyl compounds (aldehydes, ketones and ketoacids), a main class of organic disinfection byproducts (DBPs). However, the detection of carbonyl compounds in water and wastewater is challenged by multiple difficulties inherent to their physicochemical properties. A non-target screening method involving the derivatisation of carbonyl compounds with p-toluenesulfonylhydrazine (TSH) followed by their analysis using liquid chromatography coupled to electrospray ionisation high-resolution mass spectrometry (LC-ESI-HRMS) and an advanced non-target screening and data processing workflow was developed. The workflow was applied to investigate the formation of carbonyl compounds during ozonation of different water types including lake water, aqueous solutions containing Suwannee River Fulvic acid (SRFA), and wastewater. A higher sensitivity for most target carbonyl compounds was achieved compared to previous derivatisation methods. Moreover, the method allowed the identification of known and unknown carbonyl compounds. 8 out of 17 target carbonyl compounds were consistently detected above limits of quantification (LOQs) in most ozonated samples. Generally, the concentrations of the 8 detected target compounds decreased in the order: formaldehyde > acetaldehyde > glyoxylic acid > pyruvic acid > glutaraldehyde > 2,3-butanedione > glyoxal > 1-acetyl-1-cyclohexene. The DOC concentration-normalised formation of carbonyl compounds during ozonation was higher in wastewater and SRFA-containing water than in lake water. The specific ozone doses and the type of the dissolved organic matter (DOM) played a predominant role for the extent of formation of carbonyl compounds. Five formation trends were distinguished for different carbonyl compounds. Some compounds were produced continuously upon ozonation even at high ozone doses, while others reached a maximum concentration at a certain ozone dose above which they decreased. Concentrations of target and peak areas of non-target carbonyl compounds during full-scale ozonation at a wastewater treatment plant showed an increase as a function of the specific ozone dose (sum of 8 target compounds ∼ 280 µg/L at 1 mgO3/mgC), followed by a significant decrease after biological sand filtration (> 64–94% abatement for the different compounds). This highlights the biodegradability of target and non-target carbonyl compounds and the importance of biological post-treatment.

Integration of ozonation with water treatment for pharmaceuticals removal from Arroio Diluvio in southern Brazil.

Pharmaceutical compounds can reach water bodies through sewage systems. The process of water treatment is insufficient for the removal of these contaminants. The ozonation has great potential to be integrated into the treatment, since it promotes the reduction of pharmaceuticals, reduces the generation of disinfection byproducts and can reduce operational costs. In this work, the integration of the ozonation process with water treatment was studied. The ozone was applied in the pre-oxidation and intermediate ozonation stages, to evaluate the dependence of different variables. Water samples were collected from Arroio Diluvio, a river of the city of Porto Alegre (Brazil). The doses of ozone were maintained between 0.5 and 1.0 mgO3 L-1 while the coagulant was between 25 and 150 mg·L-1. Pre-ozonation resulted in a removal of pharmaceuticals at pH 10.0, time of 15 min and coagulant concentration of 52.5 mgL-1. The intermediate ozonation provided a removal with pH 10.0 and a time of 5 min of bubbling. Based on the results, it was confirmed that the synergy of the ozonation process with conventional water treatment is an effective, sensitive and fast method for the removal of pharmaceuticals from the aqueous medium.

Efficiency and Mechanism of O3-SBBR Combined Process for Advanced Treatment of Biochemical Effluent from Printing and Dyeing Industrial Park

With the aim of addressing the difficult problem of biodegradable organic nitrogen in biochemical effluent of a printing and dyeing industrial park, the combined ozonation-sequencing batch biofilm reactor (O3-SBBR) process was used for advanced treatment. The influencing factors and degradation kinetics were analyzed; quenching experiments were carried out; and the types of free radicals, succinate dehydrogenase activity, and denitrification function genes were determined. The results showed that the suitable ozonation condition was pH 8.0-8.5, O3 concentration was approximately 35.0 mg·L-1, O3 dosage was approximately 100.0 mg·L-1, and reaction time was 90.0-120.0 min. Organic nitrogen in the biochemical effluent by ozonation conformed to the pseudo first-order kinetic model, and the maximum rate constant k was 0.01035 min-1 (experimental conditions:pH 8.0, ozone dosage 150.0 mg·L-1, and ozone concentration 35.0 mg·L-1). Ozonation significantly improved the denitrification performance of the sequencing biofilm batch reactor (SBBR), and the denitrification efficiency increased from 19.8% (SBBR) to 32.9% (O3-SBBR). Ozonation could convert organic nitrogen and organic substances with strong toxicity and difficult biological utilization into small molecular substances with low toxicity and biodegradability. The abundance of functional genes (nirS, nirK, and nor) in the O3-SBBR combined process was significantly higher than that in the single SBBR, which further confirmed that ozonation could improve the nitrogen removal performance of SBBR. The operation cost of the combined process was 0.74-1.07 yuan·m-3, with good technical economy. This study provided a basis for the application of the O3-SBBR combined process in the advanced treatment of biochemical effluent in printing and dyeing industrial parks.

Unraveling the over-oxidation inhibition mechanism during the hybrid ozonation-coagulation process: Immediate entrapment and complexation between intermediate organic matter and coagulants

Pre-ozonation coagulation process had a very low and narrow range of ozone dosages for enhancing the dissolved organic matter (DOC) removal efficiency, in which over-oxidation may occur if the ozone dosage was not strictly controlled. In contrast, the proposed hybrid ozonation-coagulation (HOC) process with higher oxidation ability notably inhibited over-oxidation in this study, and exhibited improved DOC removal efficiency compared with coagulation at a much wider range of ozone dosages at different initial pH for the treatment of WWTP effluent. The HOC process also had a higher DOC removal efficiency than pre-ozonation coagulation. According to zeta potential analysis, a rising trend indicated that complexation between organic matter and metal coagulants persisted throughout the HOC process. However, the zeta potential remained almost unchanged during subsequent coagulation after pre-ozonation at high ozone dosages. Synchronous fluorescence spectroscopy analysis revealed that immediate entrapment and complexation between hydrolysed coagulants and oxidized intermediate organic matter occurred in the HOC process. Furthermore, FT-IR analysis showed that more oxygen-containing functional groups were generated, which were effectively trapped by metal coagulants and readily flocculated. To further prove the immediate entrapment and complexation during the HOC process, UPLC-Q-TOF-MS was applied to analyze the intermediate organic matter in the supernatant and flocs. The results implied that C21- organic matter was oxidized and decomposed into C11-C20, and C11-C20 intermediate organic matter was trapped and complexed by metal coagulants once formed, which led to the increase of C11-C20 in the flocs. Nevertheless, the catalytic ozonation process (γ-Al2O3/O3) with the same oxidation ability as the HOC process decomposed the organic matter into C1-C10. XPS analysis further confirmed the immediate entrapment and removal of aliphatic/aromatic carbon and oxygen-containing functional groups during the HOC process. Therefore, over-oxidation can be effectively inhibited, and wide range of ozone dosages was obtained during the HOC process, which facilitate the application of the HOC process.

Insights into the efficient ozonation process focusing on 2,4-di-tert-butylphenol - A notable micropollutant of typical bamboo papermaking wastewater: Performance and mechanism.

The present study applied the ozonation process to degrade 2,4-di-tert-butylphenol (2,4-DTBP), an emerging micropollutant detected in typical bamboo pulp and papermaking wastewater (BPPW). The effects of various influencing factors on the degradation performance and corresponding degradation mechanism were investigated. The results showed that ozone could degrade 2,4-DTBP rapidly with a reaction rate constant of (1.80±0.05)×105 M-1·s-1. The removal efficiency of 2,4-DTBP (5mg/L) could reach 100% when the ozone dosage exceed 6mg/L in a neutral medium. The presence of coexisting chemicals in BPPW such as Cl- and HCO3- promoted the removal performance of 2,4-DTBP. In contrast, NH4+ and humic acid presented inhibition on 2,4-DTBP removal. The ozonation of 2,4-DTBP was dominated by the ozone molecule, and this was primarily attributed to electrophilic substitution and 1,3-dipolar cycloaddition reactions. Twenty-seven kinds of intermediate products were identified by UPLC-Q-TOF/MS. The variations in their productions were based on the changes in ozone dosage. The degradation pathways were proposed. The toxicity of 2,4-DTBP was weakened after ozonation. As for the ozonation of actual biochemical effluent of BPPW, the desirable treatment performance was obtained. This study proved the feasibility of ozonation and provided data basis for subsequent pilot study.

New insight into the enhanced ozonation of malodorous compounds by Cu(II): Inhibiting the formation of free radicals to promote ozone utilization.

Metal-enhanced ozonation can greatly improve the decay of organic matter; however, whether this method benefits the decay of malodorous compounds or not and the possible mechanism are not well understood. In this study, nine typical malodorous compounds were selected to reveal that Cu(II)-enhanced ozonation can greatly promote the decay of fatty amines because of the direct ozone oxidation, which was enhanced to promote ozone utilization. Moreover, trace Cu(II) can amplify the observed rate constants of dimethylamine and trimethylamine for 48.9% and 155.7%, respectively, and Cu(II) dosage was the determining factor using response surface methodology to investigate the interactions between initial pH, Cu(II) dosage and ozone dosage. These results demonstrated that the formation of •OH and O2•- was inhibited rather than promoted, which was quite different from some previously reported Cu(II)-enhanced ozonation counterparts. Moreover, the enhanced effect of trace Cu(II) was exhibited in both single and complex malodorous compounds. The conversion pathway of nitrogen and sulfur elements was clarified, with the targeted mineralization of nitrogen of nitrogen-containing malodorous compounds into NO3-N and the odor characteristics of sulfur-containing malodorous compounds disappeared. These findings provided new insight for utilizing metal ions to enhance the direct ozone oxidation capacity of malodorous compounds.

State of Art and Perspectives in Catalytic Ozonation for Removal of Organic Pollutants in Water: Influence of Process and Operational Parameters

The number of organic pollutants detected in water and wastewater is continuously increasing thus causing additional concerns about their impact on public and environmental health. Therefore, catalytic processes have gained interest as they can produce radicals able to degrade recalcitrant micropollutants. Specifically, catalytic ozonation has received considerable attention due to its ability to achieve advanced treatment performances at reduced ozone doses. This study surveys and summarizes the application of catalytic ozonation in water and wastewater treatment, paying attention to both homogeneous and heterogeneous catalysts. This review integrates bibliometric analysis using VOS viewer with systematic paper reviews, to obtain detailed summary tables where process and operational parameters relevant to catalytic ozonation are reported. New insights emerging from heterogeneous and homogenous catalytic ozonation applied to water and wastewater treatment for the removal of organic pollutants in water have emerged and are discussed in this paper. Finally, the activities of a variety of heterogeneous catalysts have been assessed using their chemical–physical parameters such as point of zero charge (PZC), pKa, and pH, which can determine the effect of the catalysts (positive or negative) on catalytic ozonation processes.

Application of plant-based coagulant with a novel MnO2.MoS2 nanocatalyst in coagulation/photocatalytic ozonation process for wastewater treatment

ABSTRACT In this work, Lallemantia royleana seed mucilage (LRSM) was applied as a plant based coagulant in the initial stage of an integrated method for dye degradation. Photocatalytic ozonation (PCO) process was used under visible-light irradiation in the post-treatment stage. MnO2.MoS2 heterostructure nanocomposite was fabricated by hydrothermal synthesis and applied for the first time in PCO to mineralize Acid Blue 113 dye. The synthesized nanocatalyst was characterized by FT-IR, XRD, FE-SEM, TEM, DRS and BET. Characterization of the nanocatalyst showed that the composite consisted MoS2 with a sheet-like structure and MnO2 in the form of nanoparticles with different sizes in the range of 15–30 nm. By using the response surface methodology (RSM) approach, the best operational condition in the coagulation-flocculation (CF) stage has been acquired at pH 5.0, LRSM dose of 220 mg/L within 27 min. By applying the PCO process, complete decolorization has been attained using 11 mg of the catalyst and 0.2 g/L.h ozone dosage within 9 min. The use of LRSM along with MnO2.MoS2 nanocatalyst in the CF/PCO combined process for treating real wastewater samples indicates that the proposed technique is highly efficient and can be effectively employed to treat dye-containing industrial effluents.

Experimental Inactivation of Microalgae in Marine Ballast Water by Microbubbles Generated through Hydrodynamic Cavitation

This paper presents a novel approach to microbubble technology for the treatment of aquatic invasive organisms in ship ballast water. The microbubbles are produced by hydrodynamic cavitation with a sudden and dramatic water pressure drop. The air and ozone microbubbles, respectively, verified the bioavailability of ship ballast water treatment using marine microalgae as an indicator. Besides the effects of an ozone injection dose, the morphological changes of cells and the effluent toxicity were investigated. Compared with the ozone microbubble treatment, the inactivation of marine microalgae by air microbubbles required a long treatment time. In the storage experiment, it was found that air microbubbles did not inhibit the growth of microalgae cells, and that the injection of active matter such as ozone was still necessary to ensure the validity of biological invasion. However, even with very low doses of ozone, the inactivation effect of ozone microbubbles was still very evident. Overall, it helps to minimize the use of active matter to reduce the toxicity of treated water, and this has the capability to develop into an environmentally acceptable and practical ballast water treatment technology.

Enhanced Sewage Sludge Disintegration and Nutrients Release by Catalytic Microbubbles Ozonation Using Sewage Sludge-Based Char as Catalyst

Using microbubble ozonation (MO) technique to disintegrate sludge is a promising sludge treatment process. To enhance the lysis and reduction of sludge, the catalytic ozonation consisting of MO and sewage sludge derived char (SC) were combined. Total solids (TS), volatile solids (VS), total nitrogen and phosphate (TN and TP) were selected as main parameters for evaluating the treatment performance both in solids and supernatant. With the utilization of the catalytic MO, the ozone utilization and sludge reduction were largely improved. At a reaction time of 90 min, an ozone utilization efficiency exceeding 99% was achieved by using a MO system. The optical ozone and sludge char dosages of 150 mg/g suspended solids (SS) and 1 g/L were found for sludge lysis, respectively. TS and VS concentrations decreased by 43% and 56%, respectively, as compared to those of 16.7% and 17.9% obtained by the treatment with MO alone under the condition of sludge solution pH 4. The supernatant soluble chemical oxygen demand (SCOD), TN, TP, NH4+-N and NO3−-N increased by 1750%, 205%, 25%, 31% and 43%, respectively. A small amount of additional SC exhibited strong catalytic activity on dissolving organic matter of the sludge, demonstrating the positive effect caused by the heterogeneous catalytic ozonation on sludge disintegration.

Ozonation and Granular Activated Carbon Adsorption for the Removal of Refractory Organic Matter and Decolorization During Wastewater Tertiary Treatment

This study investigated two different hybrid processes for the treatment of municipal secondary-treated biological effluents to meet the reuse of recycled water requirements for organic matter and color. The two hybrid treatment approaches were an oxidation-based treatment process (coagulation–sedimentation–deep-bed filtration [CSDF]–ozone oxidation) and an adsorption-based treatment process (CSDF-granular activated carbon [GAC] adsorption). The efficiencies of ozonation and GAC adsorption in removing chemical organic demand (COD), dissolved organic carbon (DOC), and color intensity were evaluated. The effect of CSDF as the pretreatment was also studied. Ozonation showed a much higher color removal efficiency (88%, 4.7 mg/L ozone dose) than GAC adsorption (23%). Organic matter with an apparent molecular weight of 2–3 kDa, being humus-like, might be the colored fraction in the secondary and CSDF effluents. Ozonation had a stronger ability to remove these substances than GAC adsorption, resulting in a visibly higher color removal efficiency. In addition, higher COD and DOC removal were achieved by ozonation when the average ozone dose was increased to 9.1 mg/L. Although both hybrid processes were reliable for reducing organic matter and color, the results show that ozonation is more suitable for simultaneously removing refractory organic matter and color.

Simulating the impact of ozonation on biodegradation characteristics of industrial wastewater concentrated with membrane filtration

The biodegradation of raw wastewater for an organized industrial zone has been studied by means of dedicated respirometric and analytical experiments. The experimental results indicated that the investigated industrial wastewater contains mainly the soluble (slowly) hydrolysable fraction of chemical oxygen demand (COD) (58 %) while readily biodegradable and soluble inert fractions were in the order of 19 % and 3 %, respectively. Full-scale dynamic modeling results successfully confirmed the validity of estimated COD fraction and biodegradation kinetics. End of pipe wastewater reuse potential studied with a pilot plant revealed that almost 100 % soluble inert organics could be concentrated in reverse osmosis (RO) reject. Expectedly, the concentration was far above the COD discharge limit of 200 mg/L. Subsequently, the application of specific ozone dose around 7 kg O3/(kg COD·hour) on RO concentrates was not sufficient to secure the discharge limit by itself. However, the ozone oxidation converted 85 % of inert COD into the (soluble) slowly biodegradable organic matter. The modeling studies also showed that biodegradable organic matter generated by ozonation has much lower degradation kinetics compared to mainstream sequencing batch reactor system.

ОБ ИСПОЛЬЗОВАНИИ ОЗОННОЙ ТЕХНОЛОГИИ: ОБЗОР ПОСЛЕДНИХ РАЗРАБОТОК

. In the context of increasing anthropogenic load on the environment and, as a result, deterioration of the environmental situation in the world, there is growing interest in the use of ozone for the purification of toxic emissions, drinking water treatment, and in technological processes of various industries. Modern ozone technologies have high application efficiency, relatively low costs for implementation and operation of installations, as well as environmental safety. During the research, the factors influencing the impact of ozonation processes on the environment were studied, modern technological developments and solutions for minimizing the risks associated with the dosage of ozone were analyzed, the possibilities of effective use of ozone technology in various fields of industry were studied, and examples of successful adaptation of innovative developments in the field of ozonation were considered. The results of the study have significant practical significance for increasing the level of criteria for the success of purification processes that are inextricably linked with production, as well as the living conditions of modern society against the backdrop of the growing need to green the processes of purification and neutralization of harmful substances.

Effects of detention time and ozone dosage on organic content removal and biodegradability index in high salinity leachate

Effects of detention time and ozone dosage on organic content removal and biodegradability index in high salinity leachate

Degradação de fármacos em efluentes sanitários pela combinação de processos de oxidação e foto-oxidação

Abstract Most conventional sewage treatment systems are not able to fully remove micropollutants found in sewage. Thus, the simultaneous degradation of 11 pharmaceuticals identified in the effluent of a sewage treatment plant in Southern Brazil was herein investigated through advanced oxidation processes based on ozonation, ultraviolet radiation and hydrogen peroxide. For detection, samples were prepared through solid-phase extraction and pharmaceuticals were identified through ultra-high performance liquid chromatography tandem mass spectrometry. Active ingredients such as ciprofloxacin, oxytetracycline, paracetamol, sulfamethoxazole and trimethoprim had their concentrations increased for degradation analysis purposes. Trials were carried out on a bench at room temperature and neutral pH, with aliquots collected at 7.5 and 15 minutes. Two ozone doses (0.5 and 0.9 mg per mg of dissolved organic carbon), and combinations of the lowest ozone dose with photolysis (254 nm) and with 25 mg.L−1 of hydrogen peroxide were evaluated. Pharmaceuticals mineralization efficiency was assessed in a total organic carbon analyzer. The process combining ozone, hydrogen peroxide and ultraviolet radiation was the most efficient in the degradation of all pharmaceuticals detected in this study, since it enabled reducing oxytetracycline by 89.32%, caffeine by 96.79%, trimethoprim by 97.40%, ciprofloxacin by 97.75%, sulfamethoxazole by 99.79%, paracetamol by 99.96%, and clindamycin, ofloxacin, sulfadiazine, sulfathiazole and tylosin by 100%. This process also recorded the highest mineralization rate (60.52%), fact that confirmed the potential to decrease persistent pharmaceuticals found in conventional sewage treatment systems.

The study of optimal ozone dose for industrial ozone installation in textile wastewater reuse

The study of optimal ozone dose for industrial ozone installation in textile wastewater reuse

Modified electrolyte leakage method for testing the oxidative stability of Pinus mugo Turra under ozone-induced stress

Abstract Electrolyte leakage (EL) is the method commonly used to test the cell membrane integrity of plants under stress conditions. The cells of the leaf may be damaged by ozone (O3) entering the intercellular space as an oxidative stress agent. The modified EL method was used to test the oxidative stability (OxS) of plant tissue against O3-induced oxidative stress. The modification includes simulation of the artificial oxidative stress by additional ozonation of plant samples in the laboratory chamber. This modified EL method was applied to Pinus mugo Turra needle samples collected in the subalpine zone of the High Tatra Mts (Western Carpathians), in the years 2019 and 2020. Changes in the chemical composition of samples after artificial ozonation were traced by gas chromatography/mass spectrometry (GC/MS) analysis. In addition, O3 uptake through open stomata was estimated by calculation of the modelled ozone dose (MO3D). We also conducted an inspection of visible injury (VIN) on the needle surface focused on the occurrence of O3-induced symptoms and biotic harmful agents. Regarding OxS results as well as VIN indices, P. mugo needles showed relatively low sensitivity to oxidative stress induced by O3. Therefore MO3D in a range between 14 and 16 mmol m−2 can be considered as O3 dose with minor phytotoxic effect on P. mugo growing in the mountains of central-eastern Europe.