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    Virucidal Efficacy of Blue LED and Far-UVC Light Disinfection against Feline Infectious Peritonitis Virus as a Model for SARS-CoV-2
    (MDPI (Basel, Switzerland), 2021-08) Gardner A; Ghosh S; Dunowska M; Brightwell G; Tannock G; Kim H
    Transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) occurs through respiratory droplets passed directly from person to person or indirectly through fomites, such as common use surfaces or objects. The aim of this study was to determine the virucidal efficacy of blue LED (405 nm) and far-UVC (222 nm) light in comparison to standard UVC (254 nm) irradiation for the inactivation of feline infectious peritonitis virus (FIPV) on different matrices as a model for SARS-CoV-2. Wet or dried FIPV on stainless steel, plastic, or paper discs, in the presence or absence of artificial saliva, were exposed to various wavelengths of light for different time periods (1-90 min). Dual activity of blue LED and far-UVC lights were virucidal for most wet and dried FIPV within 4 to 16 min on all matrices. Individual action of blue LED and far-UVC lights were virucidal for wet FIPV but required longer irradiation times (8-90 min) to reach a 4-log reduction. In comparison, LED (265 nm) and germicidal UVC (254 nm) were virucidal on almost all matrices for both wet and dried FIPV within 1 min exposure. UVC was more effective for the disinfection of surfaces as compared to blue LED and far-UVC individually or together. However, dual action of blue LED and far-UVC was virucidal. This combination of lights could be used as a safer alternative to traditional UVC.
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    Global assessment of chemical quality of drinking water: The case of trihalomethanes
    (Elsevier Ltd, 15/02/2023) Villanueva CM; Evlampidou I; Ibrahim F; Donat-Vargas C; Valentin A; Tugulea A-M; Echigo S; Jovanovic D; Lebedev AT; Lemus-Pérez M; Rodriguez-Susa M; Luzati A; de Cássia Dos Santos Nery T; Pastén PA; Quiñones M; Regli S; Weisman R; Dong S; Ha M; Phattarapattamawong S; Manasfi T; Shaibu-Imodagbe EM; Eng A; Janák K; Rush SC; Reckhow D; Krasner SW; Vineis P; Richardson SD; Kogevinas M
    BACKGROUND: Trihalomethanes (THM), a major class of disinfection by-products, are widespread and are associated with adverse health effects. We conducted a global evaluation of current THM regulations and concentrations in drinking water. METHODS: We included 120 countries (∼7000 million inhabitants in 2016), representing 94% of the world population. We searched for country regulations and THM routine monitoring data using a questionnaire addressed to referent contacts. Scientific and gray literature was reviewed where contacts were not identified or declined participation. We obtained or estimated annual average THM concentrations, weighted to the population served when possible. RESULTS: Drinking water regulations were ascertained for 116/120 (97%) countries, with 89/116 (77%) including THM regulations. Routine monitoring was implemented in 47/89 (53%) of countries with THM regulations. THM data with a varying population coverage was obtained for 69/120 (58%) countries consisting of ∼5600 million inhabitants (76% of world's population in 2016). Population coverage was ≥90% in 14 countries, mostly in the Global North, 50-89% in 19 countries, 11-49% among 21 countries, and ≤10% in 14 countries including India, China, Russian Federation and Nigeria (40% of world's population). DISCUSSION: An enormous gap exists in THM regulatory status, routine monitoring practice, reporting and data availability among countries, especially between high- vs. low- and middle-income countries (LMICs). More efforts are warranted to regulate and systematically assess chemical quality of drinking water, centralize, harmonize, and openly report data, particularly in LMICs.
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    Evaluating a novel UV device for wastewater disinfection : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Environmental Technology and Sustainable Energy at Massey University, Manawatu Campus, Palmerston North, New Zealand
    (Massey University, 2014) Huang, Huijian
    UV disinfection is the most common method used in wastewater disinfection. However, some types of wastewater effluent have a low UV transmittance (UVT), which cannot be disinfected efficiently by a commercial UV reactor. A novel UV reactor (called the project prototype) was developed, which has a different type of reactor hydraulics than a typical commercial UV reactor. This change in hydraulics is believed to be an innovative method of improving the low UVT fluid disinfection. The main purpose of this project is to evaluate the feasibility the project prototype. The settings of the project prototype were first refined, and then compared to a control reactor, which was used to mimic a commercial UV reactor (called the commercial unit) at a range of UV doses. The UV dose was manipulated by changing the number of operated UV lamps and operated flow rate of the reactors. The disinfection performance of the reactors was not only compared at conventional wastewater treatment plants, but also at stabilization ponds. Within the conventional wastewater treatment plants, the reactors were tested using the effluent from the primary, secondary and tertiary treatment stages. In total, the reactors were compared twelve times at seven different wastewater treatment sites. The results show that the project prototype was, on average, 1.4 times worse than the commercial unit at treating tertiary wastewater, where the wastewater had a high UVT (55 to 65%). This high UVT value favours the use of the commercial unit, as it is designed for this UVT range. However, at a low UVT range, the project prototype performed, on average, 1.4 times better than the commercial unit, at treating secondary wastewater, where the wastewater had UVT of 22 to 55 %. In the stabilization pond tests, where the UVT was 11 to 25%, the project prototype performed 2.1 times better than the commercial unit on average, and up to 8 times better at one location. In the primary treatment test, where the UVT of the wastewater was extremely low (5%), the project prototype, on average, performed 4.5 times better than the commercial unit, and in one case up to 13 times better than the commercial unit. The research found that the project prototype has an advantage when treating low UVT fluid and great potential in the commercial market. The project prototype performs better than the commercial unit at stabilization ponds. This suggests that the project prototype would be a viable option for pond treated wastewater disinfection. In addition, the project prototype offers superior performance on primary treated wastewater. This indicates the potential application at marine outfalls (primary treated wastewater), and the possibility of primary wastewater disinfection for irrigation. Overall, this research confirms the feasibility of the novel reactor in wastewater disinfection.