RESUMEN
The control of infectious diseases can be improved via carefully designed decontamination equipment and systems. Research interest in ozone (a powerful antimicrobial agent) has significantly increased over the past decade. The COVID-19 pandemic has also instigated the development of new ozone-based technologies for the decontamination of personal protective equipment, surfaces, materials, and indoor environments. As this interest continues to grow, it is necessary to consider key factors affecting the applicability of lab-based findings to large-scale systems utilizing ozone. In this review, we present recent developments on the critical factors affecting the successful deployments of industrial ozone technologies. Some of these include the medium of application (air or water), material compatibility, efficient circulation and extraction, measurement and control, automation, scalability, and process economics. We also provide a comparative assessment of ozone relative to other decontamination methods/sterilization technologies and further substantiate the necessity for increased developments in gaseous and aqueous ozonation. Modeling methodologies, which can be applied for the design and implementation of ozone contacting systems, are also presented in this review. Key knowledge gaps and open research problems/opportunities are extensively covered including our recommendations for the development of novel solutions with industrial importance.
RESUMEN
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 mins) 20,000 garments within an 8-hour shift, based on a transfer time of 2 mins 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.
RESUMEN
With the advent of the COVID-19 pandemic, there has been a global incentive for applying environmentally sustainable and rapid sterilization methods, such as ultraviolet-C radiation (UVC) and ozonation. Material sterilization is a requirement for a variety of industries, including food, water treatment, clothing, healthcare, medical equipment, and pharmaceuticals. It becomes inevitable when devices and items like protective equipment are to be reused on/by different persons. This study presents novel findings on the performance of these sterilization methods using four microorganisms (Escherichia coli , Staphylococcus aureus , Candida albicans , and Aspergillus fumigatus) and six material substrates (stainless steel, polymethyl methacrylate, copper, surgical facemask, denim, and a cotton-polyester fabric). The combination of both ozone and UVC generally yields improved performance compared to their respective applications for the range of materials and microorganisms considered. Furthermore, the effectiveness of both UVC and ozone was higher when the fungi utilized were smeared onto the nonabsorbent materials than when 10 µL droplets were placed on the material surfaces. This dependence on the contaminating liquid surface area was not exhibited by the bacteria. This study highlights the necessity of adequate UVC and ozone dosage control as well as their synergistic and multifunctional attributes when sterilizing different materials contaminated with a wide range of microorganisms.
RESUMEN
Ozone - a powerful antimicrobial agent, has been extensively applied for decontamination purposes in several industries (including food, water treatment, pharmaceuticals, textiles, healthcare, and the medical sectors). The advent of the COVID-19 pandemic has led to recent developments in the deployment of different ozone-based technologies for the decontamination of surfaces, materials and indoor environments. The pandemic has also highlighted the therapeutic potential of ozone for the treatment of COVID-19 patients, with astonishing results observed. The key objective of this review is to summarize recent advances in the utilisation of ozone for decontamination applications in the above-listed industries while emphasising the impact of key parameters affecting microbial reduction efficiency and ozone stability for prolonged action. We realise that aqueous ozonation has received higher research attention, compared to the gaseous application of ozone. This can be attributed to the fact that water treatment represents one of its earliest applications. Furthermore, the application of gaseous ozone for personal protective equipment (PPE) and medical device disinfection has not received a significant number of contributions compared to other applications. This presents a challenge for which the correct application of ozonation can mitigate. In this review, a critical discussion of these challenges is presented, as well as key knowledge gaps and open research problems/opportunities.
RESUMEN
The novel coronavirus disease (COVID-19) pandemic outbreak is the most startling public health crises with attendant global socio-economic burden ever experienced in the twenty-first century. The level of devastation by this outbreak is such that highly impacted countries will take years to recover. Studies have shown that timely detection based on accelerated sample testing and accurate diagnosis are crucial steps to reducing or preventing the spread of any pandemic outbreak. In this opinionated review, the impacts of metal organic frameworks (MOFs) as a biosensor in a pandemic outbreak is investigated with reference to COVID-19. Biosensing technologies have been proven to be very effective in clinical analyses, especially in assessment of severe infectious diseases. Polymerase chain reactions (PCR, RT-PCR, CRISPR) - based test methods predominantly used for SARS-COV-2 diagnoses have serious limitations and the health scientists and researchers are urged to come up with a more robust and versatile system for solving diagnostic problem associated with the current and future pandemic outbreaks. MOFs, an emerging crystalline material with unique characteristics will serve as promising biosensing materials in a pandemic outbreak such as the one we are in. We hereby highlight the characteristics of MOFs and their sensing applications, potentials as biosensors in a pandemic outbreak and draw the attention of researchers to a new vista of research that needs immediate action.
RESUMEN
BACKGROUND: This rapid evidence review identifies and integrates evidence from epidemiology, microbiology and fluid dynamics on the transmission of SARS-CoV-2 in indoor environments. METHODS: Searches were conducted in May 2020 in PubMed, medRxiv, arXiv, Scopus, WHO COVID-19 database, Compendex & Inspec. We included studies reporting data on any indoor setting except schools, any indoor activities and any potential means of transmission. Articles were screened by a single reviewer, with rejections assessed by a second reviewer. We used Joanna Briggs Institute and Critical Appraisal Skills Programme tools for evaluating epidemiological studies and developed bespoke tools for the evaluation of study types not covered by these instruments. Data extraction and quality assessment were conducted by a single reviewer. We conducted a meta-analysis of secondary attack rates in household transmission. Otherwise, data were synthesised narratively. RESULTS: We identified 1573 unique articles. After screening and quality assessment, fifty-eight articles were retained for analysis. Experimental evidence from fluid mechanics and microbiological studies demonstrates that aerosolised transmission is theoretically possible; however, we found no conclusive epidemiological evidence of this occurring. The evidence suggests that ventilation systems have the potential to decrease virus transmission near the source through dilution but to increase transmission further away from the source through dispersal. We found no evidence for faecal-oral transmission. Laboratory studies suggest that the virus survives for longer on smooth surfaces and at lower temperatures. Environmental sampling studies have recovered small amounts of viral RNA from a wide range of frequently touched objects and surfaces; however, epidemiological studies are inconclusive on the extent of fomite transmission. We found many examples of transmission in settings characterised by close and prolonged indoor contact. We estimate a pooled secondary attack rate within households of 11% (95% confidence interval (CI) = 9, 13). There were insufficient data to evaluate the transmission risks associated with specific activities. Workplace challenges related to poverty warrant further investigation as potential risk factors for workplace transmission. Fluid mechanics evidence on the physical properties of droplets generated by coughing, speaking and breathing reinforce the importance of maintaining 2 m social distance to reduce droplet transmission. CONCLUSIONS: This review provides a snap-shot of evidence on the transmission of SARS-CoV-2 in indoor environments from the early months of the pandemic. The overall quality of the evidence was low. As the quality and quantity of available evidence grows, it will be possible to reach firmer conclusions on the risk factors for and mechanisms of indoor transmission.