Different Swiss freshwater samples spiked with 3,4-dimethoxyphenol (DMOP) or 2,4,6-trimethylphenol (TMP) were irradiated using UV-A and visible light from a medium-pressure mercury lamp. The kinetics of depletion of both phenols at pH 8 revealed that in almost all samples the probe phenols disappeared more rapidly at 0.1 microM than 5 microM initial concentration. Pseudo-first-order rate coefficients were on average 2-3 times greater at the lower initial phenol concentration. A comparable effect was observed using buffered solutions of Suwannee River fulvic acid, which was also used as a model photosensitizer to study the influence of various parameters on such rate coefficients. Sensitizer concentration and photon fluence rate were found to be directly proportional to the rate coefficients for DMOP transformation at both initial concentrations. For both phenols, the rate coefficients increased with increasing pH in the range 4-10, but such an increase was much more pronounced at 0.1 microM than at 5 microM initial phenol concentration. The observed kinetic behavior is compatible with the assumption that electron-rich phenols are transformed by photooxidants of different lifetimes generated by photosensitization from the dissolved organic matter (DOM).
The COVID-19 pandemic had significant impact on water utilities, which had to continue providing clean water under safe-distancing measures. Water use patterns were affected, shifting peak demand and changing volumes, though, changes varied from place to place. This study analyses the effects of the safe-distancing measures on water use patterns in different countries and cities with the aim of drawing general conclusions on causes and impacts of changes in water use patterns, as well as providing some insights on the impacts on finances of utilities and potential long-term implications. The analysis is based on information collected by the members of the IWA Specialist Group on Statistics and Economics for: Belgium, Cyprus, Germany, Japan, Switzerland, Portugal, Romania, Netherlands and Singapore. Temporal, spatial/sectoral and volume changes can be distinguished. The main temporal change in domestic water use was a delay in the morning peak, while commercial water use patterns changed significantly. In general, the volume of domestic water use increased between about 3 and 8%, while non-domestic water use decreased between about 2 and 11% over 2020. Indirect evidence suggests shifts have taken place between sectors and spatially. The impact on finances of utilities has likely been only short-term.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.