Is ozone production able to explain the good performance of CabECO® technology in wastewater treatment?

Ozone disinfection of waterborne pathogens: A review of mechanisms, applications, and challenges

Water serves as a critical vector for the transmission of pathogenic microorganisms, playing a pivotal role in the emergence and propagation of numerous diseases. Ozone (O3) disinfection technology offers promising potential for mitigating the spread of these pathogens in aquatic environments. However, previous studies have only focused on the inactivated effect of O3 on a single pathogenic microorganism, lacking a comprehensive comparative analysis of various influencing factors and different types of pathogens, while the cost-effectiveness of O3 technology has not been mentioned. This review synthesized the migration characteristics of various pathogenic microorganisms in water bodies and examined the properties, mechanisms, and influencing factors of O3 inactivation. It evaluated the efficacy of O3 against diverse pathogens, namely bacteria, viruses, protozoa, and fungi, and provided a comparative analysis of their sensitivities to O3. The formation and impact of harmful disinfection by-products (DBPs) during the O3 inactivation process were assessed, alongside an analysis of the cost-effectiveness of this method. Additionally, potential synergistic treatment processes involving O3 were proposed. Based on these findings, recommendations were made for optimizing the utilization of O3 in water inactivation in order to formulate better inactivation strategies in the post-pandemic eras.

Remediation of soils contaminated with methomyl using electrochemically produced gaseous oxidants

This prospective work focuses on the use of two different gaseous oxidants (chlorine dioxide and ozone) to remediate soil polluted with methomyl in two different applications: ex-situ and in-situ. In the first, the soil washing is integrated with the bubbling of the oxidant, while in the second, the gas was introduced by a perforated pipe located sub-superficially. Regarding the soil washing treatment, results demonstrate that direct use of ozone is not very efficient, although an important improvement is obtained following activation with hydrogen peroxide or UV light. In contrast, chlorine dioxide exhibited complete methomyl depletion from the soil, although with higher energy consumption and technical complexity compared to ozone. The direct dosing of the gaseous oxidants in perforated pipes is effective, achieving methomyl removals of 7.8 % and 9.2 % using ozone and chlorine dioxide, respectively. In these cases, soil conditions are not significantly modified, which becomes an important advantage of the technology as compared with other electrochemically assisted soil remediation process, in which large regions of the treated soil are affected by important changes in the pH or by depletion of ions. This lower impact makes these novel technologies more promising for further evaluations.

Toward real applicability of electro-ozonizers: Paying attention to the gas phase using actual commercial PEM electrolyzers technology

This work focuses on increasing the TRL of electro-ozonizer technology by evaluating the effect of electrolyte composition and operation conditions on the production of ozone, using an actual commercial cell, CONDIAPURE®, in conditions similar to what could be expected in a real application. Not only is attention paid to the changes in the concentration of ozone in the liquid phase, but also to those observed in the gas phase. The electrolyte and its recirculation flowrate, as well as operation temperatures and pressures are found to have significant influence on production rates. The most efficient way to produce ozone is operating at low temperatures and high pressures. In this work, 0.25 and 0.21 mg O₃/min were obtained operating at 10 A in electrolytes consisting of aqueous solutions of perchloric and sulfuric acid, respectively, in tests carried out at 13 °C and 2 bars of gauge pressure. The negative effect of scavengers that appear electrochemically along the production of ozone is very important and seems to be partially compensated when organics are present in the solution due to the competition between the reaction of these scavengers with ozone or organics.