Use of ozonation technology to combat viruses and bacteria in aquatic environments: problems and application perspectives for SARS-CoV-2.

COVID-19 is a global health threat with a large number of confirmed cases and deaths worldwide. Person-to-person transmission through respiratory droplets and contact with aerosol-infected surfaces are the main ways in which the virus spreads. However, according to the updated literature, the new coronavirus (SARS-CoV-2) has also been detected in aqueous matrices, with the main route of transmission being feces and masks from patients diagnosed with the disease. Given the emergence of public health and environmental protection from the presence of lethal viruses and bacteria, this review article aims to report the major challenges associated with the application of ozonation in water contaminated with viruses and bacteria, in order to clarify whether these communities can survive or infect after the disinfection process and if it is efficient. Available data suggest that ozonation is able to increase the inactivation effect of microorganisms by about 50% in the logarithmic range, reducing infectivity. In addition, the evidence-based knowledge reported in this article is useful to support water and sanitation safety planning and to protect human health from exposure to cited contaminants through water.

Evaluating the Effectiveness of Intravenous Ozonated Normal Saline in the Treatment of Severe COVID-19 Disease: A randomized control trial

Background: There is still no specific treatment strategy for COVID-19 other than supportive management. The potential biological benefits of ozone therapy include reduced tissue hypoxia, decreased hypercoagulability, modulated immune function by inhibiting inflammatory mediators, improved phagocytic function, and impaired viral replication. This study aimed to evaluate the effect of intravenous ozonated normal saline on patients with severe COVID-19 disease. Method(s): In this study, a single centralized randomized clinical trial was conducted on 80 hospitalized patients with severe COVID-19. The patients were selected by random allocation method and divided into two groups A and B. In group A (control group), patients were given standard drug treatment, and in group B (intervention group), patients received ozonated normal saline in addition to the standard drug treatment. In the intervention group, 400 mL of normal saline was weighed by 40 mug/ kg of body weight and was injected into patients within 15 to 30 minutes (80 to 120 drops per minute). This process was done daily every morning for a week. Primary and secondary outcomes of the disease included changes in the following items: length of hospital stay, inflammatory markers including C-reactive protein (CRP), clinical recovery, arterial blood oxygen status, improvement of blood disorders such as leukopenia and leukocytosis, duration of ventilator attachment, and rapid clearance of lung lesions on CT scans. The need for intensive care unit (ICU) hospitalization, the length of ICU stay, and the mortality rate in patients of the two groups was compared. Result(s): According to the results of the initial outcome variable analysis, the probability of discharge of patients who received the normal ozonated saline intervention was 33% higher than patients who did not receive this intervention;however, this relationship was not statistically significant (HR = 0.67, 95%, CI = 0.42-1.06, P value = 0.089). The chance of ICU hospitalization in patients of the intervention group was three times more than that of the comparison group, but this relationship was not significant (odds ratio = 4.4 95% CI = 1.32-14.50, P value = 0.016). The use of ozonated normal saline was found to increase the risk of death by 1.5 times but this relationship was not statistically significant (odds ratio = 1.5, 95% CI = .24-9.75, P value = 0.646). Ozonated normal saline had a significant effect on changes in respiration rate (in the intervention group the number of breaths was decreased) and the erythrocyte sedimentation rate (in the intervention group the erythrocyte sedimentation rate was increased);however, it had no significant effect on other indicators. Conclusion(s): The present study showed that ozone therapy in hospitalized patients with severe COVID-19 could help improve some primary and secondary outcomes of the disease. Governments and health policymakers should make ozone therapy an available care service so that the need for advanced treatment facilities decreases;consequently, this measure may improve patient safety, prevent lung tissue destruction, and control cytokine storms in patients. Additionally, health decision-makers need to aim for the effective clinical improvement of patients, especially severe ones, and the reduction of their mortality. However, further large-scale multicenter studies with larger sample sizes considering drug side effects and other variables influencing the clinical course of COVID-19 can provide more information on the effectiveness and importance of ozone therapy.Copyright © 2023 The Author(s);Published by Kerman University of Medical Sciences.

Disinfecting Efficacy of an Ozonated Water Spray Chamber: Scientific Evidence of the Total and Partial Biocidal Effect on Personal Protective Equipment and in Vitro Analysis of a Viral Experimental Model

Due to the high recurrence of microbial infections, developing new technologies for preventing the dissemination of pathogens is essential, especially to prevent infection in humans. Thus, devices for the decontamination of surfaces reduce not only the spread of pathogens in the environment, but provide greater security and protection for communities. Ozone (O3) is a substance capable of reducing or eliminating several types of microorganisms owing to its biocidal capacity, including when it is dissolved in water. The objective of this study was to develop an instant decontamination device using ozonated water. To confirm its biocidal action and verify the device's efficacy, the reduction of the microbial load of important pathogens on personal protective equipment (PPE) was assessed. In addition, in order to confirm the biocidal action of ozonated water against SARS-CoV-2, in vitro tests on a viral model of Gammacoronavirus were performed. The results showed the efficacy of ozonated water in the disinfection device at concentration ranges of 0.3–0.6 mg/L and 0.7–0.9 mg/L of ozonated water, with growth reductions above 2 log10 for both concentration ranges tested and inactivation fractions above 60% (0.3–0.6 mg/L) and 80% (0.7–0.9 mg/L), with a high proportion of the tested PPE showing 100% microbial reduction. In vitro results for the evaluation of ozonated water in a viral model showed a 99.9% reduction percentage in the concentration range of 0.3 to 0.5 mg/L and a 99% reduction in the concentration range of 0.6 to 0.8 mg/L, with a 5.10 log EDI50/mL and 6.95 log EDI50/mL reduction, respectively. The instant decontamination system developed in this study proved effective for microbial reduction, and we confirmed the potential of ozonated water as a biocidal agent. Therefore, the proposed decontamination device could be considered as a tool for reducing contamination on surfaces using ozonated water.

Inactivation of Pathogenic Microorganisms on Polymeric Materials through Ozonation

Ozone-based technologies have been evaluated to inactivate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on surfaces. However, the vast diversity of information makes it difficult to establish common ground for determining the best practices for using this technology. The objective of this work is to evaluate the success of N95 mask decontamination by ozonation, determining the specific parameters for process control. To quantify the effectiveness of the process, a disinfection protocol was initially developed based on two bacterial species (Escherichia coli and Staphylococcus pseudintermedius), followed by another disinfection assay using the murine hepatitis coronavirus (MHV-3), in a laboratory-scale prototype. Ozone is an effective candidate for use against SARS-CoV-2 or other viruses to disinfect personal protection equipment (PPE). © 2023 Wiley-VCH GmbH.

The possibilities of using the effects of ozone therapy in neurology

OBJECTIVES: The beneficial effects of ozone therapy consist mainly of the promotion of blood circulation: peripheral and central ischemia, immunomodulatory effect, energy boost, regenerative and reparative properties, and correction of chronic oxidative stress. Ozone therapy increases interest in new neuroprotective strategies that may represent therapeutic targets for minimizing the effects of oxidative stress. METHOD(S): The overview examines the latest literature in neurological pathologies treated with ozone therapy as well as our own experience with ozone therapy. The effectiveness of treatments is connected to the ability of ozone therapy to reactivate the antioxidant system to address oxidative stress for chronic neurodegenerative diseases, strokes, and other pathologies. Application options include large and small autohemotherapy, intramuscular application, intra-articular, intradiscal, paravertebral and epidural, non-invasive rectal, transdermal, mucosal, or ozonated oils and ointments. The combination of different types of ozone therapy stimulates the benefits of the effects of ozone. RESULT(S): Clinical studies on O2-O3 therapy have been shown to be efficient in the treatment of neurological degenerative disorders, multiple sclerosis, cardiovascular, peripheral vascular, orthopedic, gastrointestinal and genitourinary pathologies, fibromyalgia, skin diseases/wound healing, diabetes/ulcers, infectious diseases, and lung diseases, including the pandemic disease caused by the COVID-19 coronavirus. CONCLUSION(S): Ozone therapy is a relatively fast administration of ozone gas. When the correct dose is administered, no side effects occur. Further clinical and experimental studies will be needed to determine the optimal administration schedule and to evaluate the combination of ozone therapy with other therapies to increase the effectiveness of treatment.Copyright © 2021 Neuroendocrinology Letters.

Automation of Large-Scale Gaseous Ozonation: A Case Study of Textile and PPE Decontamination

There is an ever-growing need in several industries to disinfect or sanitise products (i.e., to reduce or eliminate pathogenic microorganisms from their surfaces). Gaseous ozone has been widely applied for this purpose, particularly during the era of the COVID-19 pandemic. However, the large-scale deployment of this technology usually involves a manually-operated chamber, into which articles are loaded and subsequently unloaded after treatment—a batch process. Although the development of large-scale, automated and continuous ozonation equipment has hardly been reported in the literature, this has tremendous potential for industries seeking to decontaminate certain articles/products in a rapid and effective manner. In this paper, an overview of the design and implementation considerations for such an undertaking is evaluated. By presenting a case study for a developed automated system for clothing and personal protective equipment (PPE) disinfection, we provide key data regarding the automation procedure/design's considerations, risks, material compatibility, safety, sustainability and process economics. Our analysis shows that the transfer time for garments between successive chambers and the agility of the sliding doors are crucial to achieving the desired throughput. The automated system is capable of effectively treating (20 ppm ozone for 4 min) 20,000 garments within an 8-h shift, based on a transfer time of 2 min and a sliding door speed of 0.4 m/s. The flexibility of the system allows for variation in the concentration or exposure time, depending on the contamination level and the consequent decontamination efficiency desired. This flexibility significantly limits the degradation of the material during treatment. A return on investment of 47% is estimated for this novel system. © 2023 by the authors.

Comparative evaluation of advanced oxidation processes (AOPs) for reducing SARS-CoV-2 viral load from campus sewage water.

Presence of SARS-CoV-2 in wastewater is a major concern as the wastewater meets rivers and other water bodies and is used by the population for various purposes. Hence it is very important to treat sewage water in an efficient manner in order to reduce the public health risk. In the present work, various advanced oxidation processes (AOPs) have been evaluated for disinfection of SARS-CoV-2 from sewage water collected from STP inlet of academic institutional residential. The sewage water was subjected to ten AOPs, which include Ozone (O3), Hydrodynamic cavitation (HC), Ultraviolet radiation (UV), and their hybrid combinations like HC/O3, HC/O3/H2O2, HC/H2O2, O3/UV, UV/H2O2, UV/H2O2/O3, and O3/H2O2 to reduce SARS-CoV-2 viral load. Further, AOP treated sewage water was subjected to total nucleic acid isolation followed by RT-qPCR for viral load estimation. The sewage water treatment techniques were evaluated based on their viral concentration-reducing efficiency. It was found that ozone and ozone-coupled hybrid AOPs showed the most promising result with more than 98 % SARS-CoV-2 viral load reducing efficiency from sewage water. Interestingly, the best six AOPs used in this study significantly reduced both the SARS-CoV-2 and PMMoV (faecal indicator) viral load and improved water quality in terms of increasing DO and decreasing TOC.

A comprehensive review of various approaches for treatment of tertiary wastewater with emerging contaminants: what do we know?

In the last few decades, environmental contaminants (ECs) have been introduced into the environment at an alarming rate. There is a risk to human health and aquatic ecosystems from trace levels of emerging contaminants, including hospital wastewater (HPWW), cosmetics, personal care products, endocrine system disruptors, and their transformation products. Despite the fact that these pollutants have been introduced or detected relatively recently, information about their characteristics, actions, and impacts is limited, as are the technologies to eliminate them efficiently. A wastewater recycling system is capable of providing irrigation water for crops and municipal sewage treatment, so removing ECs before wastewater reuse is essential. Water treatment processes containing advanced ions of biotic origin and ECs of biotic origin are highly recommended for contaminants. This study introduces the fundamentals of the treatment of tertiary wastewater, including membranes, filtration, UV (ultraviolet) irradiation, ozonation, chlorination, advanced oxidation processes, activated carbon (AC), and algae. Next, a detailed description of recent developments and innovations in each component of the emerging contaminant removal process is provided.

A comparative study of landfill leachate treatment using advanced oxidation photochemical processes, ozonation process and hydrogen peroxide systems

Ozonation processes and hydrogen peroxide systems can be used as advanced oxidation photochemical processes (AOPs) to treat leachate from municipal landfills. They are efficient and effective processes in the extermination of microorganisms and elimination of viruses and pathogens, including members of the virus family coronaviridae (such as MERS-CoV, SARS-CoV-1 and SARS-CoV-2), the new coronavirus COVID-19, that all countries of the world suddenly faced recently, and the result-ing emergence of many cases and injuries that exceed the absorption of hospitals, quarantine, and home self-isolation, and the abundant use of personal protective equipment, like face masks, gloves, contaminated cotton, dressings, and plaster, etc., whether in the case of infection or for prevention, and mixing of this type of waste with household waste, which increase the negative environmental impact because of the highly contaminated waste generation. This study aims to determine the most effective and safest methods of treating the leachate at optimum conditions of each process in laboratory-scale experiments at pH values (7.5–8.5).It was found that both O and O /H O effectively reduced the concentration of organic compounds under optimal experimental conditions. 3 3 2 2 O3 /H2 O2 was very effective in reducing the concentration of organic compounds in optimal experimental conditions The most effective process, with the best results were obtained at 20 mg/L of H2 O2 after increasing the treatment time to 60 min, where the efficiency of chemical oxygen demand (COD) removal was 84%–92%, the efficiency of total organic carbon removal was in the range of 29.21–58.42 mg/L. The biodegradation indicated by the biochemical oxygen demand (BOD5)/COD ratio increased from 0.17 to 0.74, and the turbidity removal efficiency was 75.60%–82.80%. © 2022 Desalination Publications. All rights reserved.

SARS-CoV-2 pseudotyped virus persists on the surface of multiple produce but can be inactivated with gaseous ozone.

Due to the immense societal and economic impact that the COVID-19 pandemic has caused, limiting the spread of SARS-CoV-2 is one of the most important priorities at this time. The global interconnectedness of the food industry makes it one of the biggest concerns for SARS-CoV-2 outbreaks. Although fomites are currently considered a low-risk route of transmission for SARS-CoV-2, new variants of the virus can potentially alter the transmission dynamics. In this study, we compared the survival rate of pseudotyped SARS-CoV-2 on plastic with some commonly used food samples (i.e., apple, strawberry, grapes, tomato, cucumber, lettuce, parsley, Brazil nut, almond, cashew, and hazelnut). The porosity level and the chemical composition of different food products affect the virus's stability and infectivity. Our results showed that tomato, cucumber, and apple offer a higher survival rate for the pseudotyped viruses. Next, we explored the effectiveness of ozone in deactivating the SARS-CoV-2 pseudotyped virus on the surface of tomato, cucumber, and apple. We found that the virus was effectively inactivated after being exposed to 15 ppm of ozone for 1 h under ambient conditions. SEM imaging revealed that while ozone exposure altered the wax layer on the surface of produce, it did not seem to damage the cells and their biological structures. The results of our study indicate that ozonated air can likely provide a convenient method of effectively disinfecting bulk food shipments that may harbour the SARS-CoV-2 virus.

A Critical Review on Diverse Technologies for Advanced Wastewater Treatment During SARS-CoV-2 Pandemic: What Do We Know?

Advanced wastewater treatment technologies are effective methods and currently attract growing attention, especially in arid and semi-arid areas, for reusing water, reducing water pollution, and explicitly declining, inactivating, or removing SARS-CoV-2. Overall, removing organic matter and micropollutants prior to wastewater reuse is critical, considering that water reclamation can help provide a crop irrigation system and domestic purified water. Advanced wastewater treatment processes are highly recommended for contaminants such as monovalent ions from an abiotic source and SARS-CoV-2 from an abiotic source. This work introduces the fundamental knowledge of various methods in advanced water treatment, including membranes, filtration, Ultraviolet (UV) irradiation, ozonation, chlorination, advanced oxidation processes, activated carbon (AC), and algae. Following that, an analysis of each process for organic matter removal and mitigation or prevention of SARS-CoV-2 contamination is discussed. Next, a comprehensive overview of recent advances and breakthroughs is provided for each technology. Finally, the advantages and disadvantages of each method are discussed.

Ozone-enhanced TiO2 nanotube arrays for the removal of COVID-19 aided antibiotic ciprofloxacin from water: Process implications and toxicological evaluation.

The purpose of this study was to evaluate the performance of synthesized TiO2 nanotube arrays (NTAs) for the removal of the COVID-19 aided antibiotic ciprofloxacin (CIP) and the textile dye methylene blue (MB) from model wastewater. Synthesis of TiO2 NTAs showed that anodization potential and calcination temperatures directly influence nanotube formation. The increased anodization potential from 10 to 40 V resulted in the development of larger porous nanotubes with a diameter of 36-170 nm, while the collapse of the tubular structure was registered at the highest applied potential. Furthermore, it was found that the 500 °C calcination temperature was the most prominent for the formation of the most photocatalytically active TiO2 NTAs, due to the optimal anatase/rutile ratio of 4.60. The degradation of both model compounds was achieved with all synthesized TiO2 NTAs; however, the most photocatalytically active NTA sample was produced at 30 V and 500 °C. Compared to photocatalysis, CIP degradation was greatly enhanced by 5-25 times when ozone was introduced to the photocatalytic cell (rates 0.4-4.2 × 10-1 min-1 versus 0.07-0.2 × 10-1 min-1). This resulted in the formation of CIP degradation by-products, with different mass-to-charge ratios from [M+H]+ 346 to 273 m/z. Even though the CIP degradation pathway is rather complex, three main mechanisms, decarboxylation, hydroxylation reaction, and piperazine ring cleavage, were proposed and explained. Furthermore, treated samples were placed in contact with the crustaceans Daphnia magna. It was found that 100% mortality was achieved when approximately 60% of the remaining TOC was present in the samples, indicating that toxic degradation by-products were formed.

A Study on the Effect of Integrated Ozone and UVC-LED Approaches on the Reduction of Salmonella typhimurium Bacteria in Droplets

In the wake of the SARS-CoV-2 pandemic, inactivating bioaerosols became a pivotal issue which helps to prevent the transmittance of SARS-CoV-2. Thus, the current study was conducted to investigate a potential inactivating method using both ozone (O-3) and ultraviolet C (UVC). Individual and integrated effects of O-3 and UVC were compared. A solution containing approximately 4 similar to 7.3 x 10(6) CFU/mL of Salmonella typhimurium bacteria was used to produce bacteria droplets. These droplets were exposed to O-3 and UVC to determine the reduction rate of bacteria. The exposure times were set as 1 and 30 minutes. Ozone concentrations were 100 and 200 ppmv. UVC-LEDs were used as a UVC source. Peak wavelength of the UVC-LED was 275 nm and the irradiation dose was 0.77 mW/cm(2). In terms of O-3 and UVC-LED interaction, 194 ppmv styrene was used as a target compound to be removed. Considering the O-3 and UVC-LED interaction, the presence of O-3 could reduce the performance of the UVC-LED, and UVC-LED could also reduce significant amount of O-3. The sequence of O-3 and UVC-LED treatment was as follows: O-3 was exposed at first, then UVC-LED, and this order showed the best reduction ratio ( > 99.9%). Therefore, if O-3 and UVC-LED is used to disinfect Salmonella typhimurium bacteria contained in droplets, bacteria should be separately exposed to O-3 and UVC-LED in order to improve the inactivation efficiency.

Quantitative evaluation of the inactivation effect of ozonated water on SARS-CoV-2 based on corrected CT values

There are many issues in the evaluation protocols based on CT (mg min/L) values, which have been used to assess the germicidal effect of highly oxidative and unstable ozonated water. The major problems include the carryover of culture medium components in virus inactivation assays and the reaction volume ratio between the virus suspension and ozonated water. Furthermore, it is essential to correct the CT value with the decay curve of dissolved ozone under the same conditions as the inactivation assay. In this study, these concerns were reexamined to obtain quantitative CT values. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) inactivation test using ozonated water prepared from pure water was assessed by determining the corrected concentration time (CCT) values. Moreover, a possible inactivation mechanism of SARS-CoV-2 was discussed with the aid of findings from this study and previous reports. The findings revealed that the CCT value required for 99.95% inactivation of SARS-CoV-2 with ozonated water was 0.97 mg·min/L. To quantitatively evaluate the SARS-CoV-2 inactivation test, the virus purification procedure during the pretreatment and the CT value correction using a dissolved ozone decay curve obtained under the same condition as the inactivation test were demonstrated to be essential.We proposed a possible mechanism of SARS-CoV-2 inactivation with ozonated water. Amino acids such as tyrosine, tryptophan, methionine, cysteine, and histidine in the SARS-CoV-2 spike protein are susceptible to oxidative attack by the ozone dissolved in water. This attack may induce structural destruction of the spike protein and inhibit its binding to the angiotensin converting enzyme 2 (ACE2) receptor, an essential host receptor for viral infection, resulting in viral inactivation and contributing to infection suppression. [ FROM AUTHOR] Copyright of Ozone: Science & Engineering is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

A Review on the Potential of Common Disinfection Processes for the Removal of Virus from Wastewater.

Due to the prevalence of the COVID-19 outbreak, as well as findings of SARS-CoV-2 RNA in wastewater and the possibility of viral transmission through wastewater, disinfection is required. As a consequence, based on prior investigations, this work initially employed the viral concentration detection technique, followed by the RT-qPCR assay, as the foundation for identifying the SARS-CoV-2 virus in wastewater. After that, the ability and efficacy of chlorine, ozone, and UV disinfection to inactivate the SARS-CoV-2 virus from wastewater were examined. Chlorine disinfection is the most extensively used disinfection technology due to its multiple advantages. With a chlorine dioxide disinfectant dose of 40 mg/L, the SARS-CoV virus is inactivated after 30 min of contact time. On the other hand, ozone is a powerful oxidizer and an effective microbicide that is employed as a disinfectant due to its positive characteristics. After 30 min of exposure to 1000 ppmv ozone, corona pseudoviruses are reduced by 99%. Another common method of disinfection is using ultraviolet radiation, which is usually 253.7 nm suitable for ultraviolet disinfection. At a dose of 1048 mJ/cm2, UVC radiation completely inactivates the SARS-CoV-2 virus. Finally, to evaluate disinfection performance and optimize disinfection strategies to prevent the spread of SARS-CoV-2, this study attempted to investigate the ability to remove and compare the effectiveness of each disinfectant to inactive the SARS-CoV-2 virus from wastewater, summarize studies, and provide future solutions due to the limited availability of integrated resources in this field and the spread of the SARS-CoV-2 virus worldwide.

Experimental and CFD evaluation of ozone efficacy against coronavirus and enteric virus contamination on public transport surfaces.

The limited information about the routes of the transmission of SARS-CoV-2 within the ongoing pandemic scenario mobilized the administration, industry and academy to develop sanitation and disinfection systems for public and private spaces. Ozone has been proposed as an effective disinfection method against enveloped and non-enveloped viruses, including viruses with similar morphology to SARS-CoV-2. Due to this efficacy, numerous gaseous and aqueous phase ozone applications have emerged potentially to inhibit virus persistence in aerosols, surfaces, and water. In this work, a numerical model, a RANS CFD model for ozone dispersion inside tram and underground coach has been developed including the chemical self-decomposition and surface reactions of the ozone. The CFD model has been developed for a real tram coach of 28.6 × 2.4 × 2.2 m (L × W × H) using 1.76 million nodes and the Menter's shear stress transport turbulence model. The model predicts the O3 concentration needed to meet disinfection criteria and the fluid dynamics inside the public transport coach. The effectiveness of the system has been validated with laboratory and field tests in real full-scale coach using porcine epidemic diarrhea virus (PEDV) and murine norovirus (MNV-1) as SARS-CoV-2 and human norovirus surrogates, respectively. Lab-scale experiments on plastic surfaces demonstrated O3 disinfection (100 ppm, 95% RH, 25 min) inactivate > 99.8% MNV-1 and PEDV. Additionally, field tests in real full-scale coach demostrate the efficacy of the system as > 98.6% of infectious MNV-1 and > 96.3% PEDV were inactivated.

Transformation of antiviral ribavirin during ozone/PMS intensified disinfection amid COVID-19 pandemic.

Due to the spread of coronavirus disease 2019 (COVID-19), large amounts of antivirals were consumed and released into wastewater, posing risks to the ecosystem and human health. Ozonation is commonly utilized as pre-oxidation process to enhance the disinfection of hospital wastewater during COVID-19 spread. In this study, the transformation of ribavirin, antiviral for COVID-19, during ozone/PMS­chlorine intensified disinfection process was investigated. •OH followed by O3 accounted for the dominant ribavirin degradation in most conditions due to higher reaction rate constant between ribavirin and •OH vs. SO4•- (1.9 × 109 vs. 7.9 × 107 M-1 s-1, respectively). During the O3/PMS process, ribavirin was dehydrogenated at the hydroxyl groups first, then lost the amide or the methanol group. Chloride at low concentrations (e.g., 0.5- 2 mg/L) slightly accelerated ribavirin degradation, while bromide, iodide, bicarbonate, and dissolved organic matter all reduced the degradation efficiency. In the presence of bromide, O3/PMS process resulted in the formation of organic brominated oxidation by-products (OBPs), the concentration of which increased with increasing bromide dosage. However, the formation of halogenated OBPs was negligible when chloride or iodide existed. Compared to the O3/H2O2 process, the concentration of brominated OBPs was significantly higher after ozonation or the O3/PMS process. This study suggests that the potential risks of the organic brominated OBPs should be taken into consideration when ozonation and ozone-based processes are used to enhance disinfection in the presence of bromide amid COVID-19 pandemic.

Can ozone inactivate SARS-CoV-2? A review of mechanisms and performance on viruses.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic has challenged societies around the globe. Technologies based on ozone, a powerful oxidant, have been evaluated to inactivate this virus in aerosols and fomites. However, the high data diversity hinders the possibility of establishing a common ground for determining best practices for the use of these technologies. Furthermore, there is a lack of consensus regarding which are the main mechanisms of ozone virus inactivation. This critical review examined the most relevant information available regarding ozone application in gas-phase for different viruses inactivation (including recent publications dealing with SARS-CoV-2), and pointed towards envelope alteration as the main reaction pathway for enveloped viruses, such as is the case of SARS-CoV-2. It could also be concluded that gaseous ozone can be indeed an effective disinfectant, successfully inactivating viruses such us influenza A H1N1, MERS-CoV, SARS-CoV-1 or even SARS-CoV-2 in aerosols or fomites. In reviewed works, low ozone exposures, just around 0.1-0.4 mg L-1 min, achieve about 4 log10 of inactivation in aerosols, while exposures between 1 and 4 mg L-1 min may be needed to guarantee an inactivation of 3-4 log10 in different fomites. Although further studies are required, ozone is an effective candidate to be used against SARS-CoV-2 or other viruses in surfaces and indoor locations.

Blood ozonization in patients with mild to moderate COVID-19 pneumonia: a single centre experience.

The emerging outbreak of the coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread worldwide. We prescribed some promising medication to our patients with mild to moderate pneumonia due to SARS-CoV-2, however such drugs as chloroquine, hydrossichloroquine, azithromycin, antivirals (lopinavir/ritonavir, darunavir/cobicistat) and immunomodulating agents (steroids, tocilizumab) were not confirmed as effective against SARS-CoV2. We, therefore, started to use auto-hemotherapy treated with an oxygen/ozone (O2/O3) gaseous mixture as adjuvant therapy. In Udine University Hospital (Italy) we performed a case-control study involving hospitalized adult patients with confirmed COVID-19 with mild to moderate pneumonia. Clinical presentations are based upon clinical phenotypes identified by the Italian Society of Emergency and Urgency Medicine (SIMEU-Società Italiana di Medicina di Emergenza-Urgenza) and patients that met criteria of phenotypes 2 to 4 were treated with best available therapy (BAT), with or without O3-autohemotherapy. 60 patients were enrolled in the study: 30 patients treated with BAT and O2/O3 mixture, as adjuvant therapy and 30 controls treated with BAT only. In the group treated with O3-autohemotherapy plus BAT, patients were younger but with more severe clinical phenotypes. A decrease of SIMEU clinical phenotypes was observed (2.70 ± 0.67 vs. 2.35 ± 0.88, p = 0.002) in all patients during hospitalization but this clinical improvement was statistically significant only in O3-treated patients (2.87 ± 0.78 vs. 2.27 ± 0.83, p < 0.001), differently to the control group (2.53 ± 0.51 vs. 2.43 ± 0.93, p = 0.522). No adverse events were observed associated with the application of O2/O3 gaseous mixture. O2/O3 therapy as adjuvant therapy could be useful in mild to moderate pneumonia due to SARS-CoV-2. Randomized prospective study is ongoing [Clinical Trials.gov ID: Z7C2CA5837].