Hepatitis A and E viruses (HAV and HEV, respectively) remain a significant global health concern despite advancements in healthcare and vaccination programs. Regular monitoring and vaccine efficacy of HAV are still lacking in different countries. This study aimed to investigate HAV and HEV prevalence in developed, developing, and least-developed Asian countries using wastewater as a surveillance tool. A total of 232 untreated wastewater samples were collected from six wastewater treatment plants, a sewage treatment plant, or an open drainage in six countries [Nepal (n = 51), Indonesia (n = 37), Thailand (n = 30), Vietnam (n = 27), the Philippines (n = 17), and Japan (n = 70)] between April and October 2022. Viruses in wastewater were concentrated by simple centrifugation or polyethylene glycol precipitation method, followed by viral RNA extraction and reverse transcription-quantitative polymerase chain reaction. HAV and HEV RNA were detected in the samples from Nepal (51 % for HAV and 2 % for HEV), Thailand (3 % for both viruses), and Japan (1 % for HAV and 24 % for HEV). Only HAV RNA was found in 11 % of the samples in Indonesia, whereas only HEV RNA was detected in Vietnam and the Philippines, with a positive ratio of 15 % and 12 %, respectively. These results highlighted the geographic variability in HAV and HEV prevalence, underscoring the need for localized public health strategies to address specific viral hepatitis challenges in each country.

Financial feasibility is usually a concern in water reclamation projects. Aside from internal benefits, water reclamation in industrial parks delivers health and environmental benefits not normally considered in cost–benefit analyses (CBA). This study investigated the influence of environmental benefits on the feasibility of water reclamation projects with flow rate scenarios in accordance with industrial parks in Chonburi, Thailand. CBAs of water reclamation plants for industrial water supply, consisting of ultrafiltration (UF) and reverse osmosis (RO), with flow rates of 5200, 10,000, 15,000, and 25,000 m³/day and discount rates of 3%, 5%, 7%, 9% and 11% were conducted. Considering only the direct costs and benefits, none of the projects were financially feasible. However, when the environmental benefits were included, the projects became profitable in all cases except those with a flow rate of 5200 m³/day and discount rates of 5%, 7%, 9%, and 11% and those with flow rates of 10,000 and 25,000 m³/day and an 11% discount rate. Further, CBAs of water reclamation projects in industrial parks for irrigation were conducted with post-treatment processes consisting of sand filtration and chlorine disinfection for flow rates of 240, 480, 2400, 3600, and 4800 m³/day. The projects are profitable, regardless of environmental benefits.

Aims A continuous quench‐flow (CQF) reactor was developed to collect samples at the reaction times of less than one second. The reactor is applied to determine ozone disinfection kinetics of poliovirus and to study whether EMA‐qPCR can assess the viral infectivity after ozone disinfection. Methods Ozone disinfection of poliovirus was conducted in the developed CQF, and the disinfection kinetics were tested in the range of 0.7 – 5.0 seconds at ozone concentration of 0.08 and 0.25 mg/L. Inactivation, damage on viral genome and damage on capsid integrity were determined by plaque assay, quantitative reverse transcription polymerase chain reaction (RT‐qPCR), and ethidium monoazide treatment coupled with RT‐qPCR (EMA‐qPCR), respectively. Results By using CQF, 2.18 and 2.76 log₁₀ reductions were observed at the reaction time of 0.7s and ozone concentration of 0.08 and 0.25 mg/L, respectively, followed by tailing. Ozone disinfection kinetics of poliovirus 1 were better fit by the efficiency factor Hom (EFH) model than by the Chick‐Watson model, or the modified Chick‐Watson model. Kinetics observed were similar between RT‐qPCR and EMA‐qPCR assays at the reaction times of less than 2.0 s and ozone concentrations of 0.08 and 0.25 mg/L. At reaction times > 5 seconds, viral concentration evaluated by EMA‐qPCR was reduced in comparison to stable RT‐qPCR results. Both assays still underestimated the virus inactivation. Conclusion The simple developed reactor can be used to investigate viral ozone disinfection kinetics and to elucidate inactivation characteristics or mechanisms at very short exposure times. Significance and Impact of the Study The developed CQF reactor is beneficial for better understanding of virus inactivation by ozone, and the reactor can be used to better elucidate disinfection kinetics and mechanisms for future research. This work constitutes an important contribution to the existing knowledge of the application and limitation of the EMA/PMA‐qPCR to assess virus infectivity after ozone disinfection.