Enhanced iodinated disinfection byproducts formation in iodide/iodate-containing water undergoing UV-chloramine sequential disinfection: Machine learning-aided identification of reaction mechanisms.

Restricted to the complex nature of dissolved organic matter (DOM) in various aquatic environments, the mechanisms of enhanced iodinated disinfection byproducts (I-DBPs) formation in water containing both I and IO (designated as I/IO in this study) during the ultraviolet (UV)-chloramine sequential disinfection process remains unclear. In this study, four machine learning (ML) models were established to predict I-DBP formation by using DOM and disinfection features as input variables. Extreme gradient boosting (XGB) algorithm outperformed the others in model development using synthetic waters and in cross-dataset generalization of surface waters.

Mixed chlorine/chloramines in disinfected water and drinking water distribution systems (DWDSs): A critical review.

Mixed chlorine/chloramines are commonly occurring in real drinking water distribution systems (DWDSs) but often overlooked. This review provides a comprehensive overview of the occurrences, characteristics, analysis methods, and control strategies of mixed chlorine/chloramines in DWDSs. The characteristics of mixed chlorine/chloramine species are summarized for treated water in drinking water treatment plants (DWTPs), secondary disinfection facilities, and DWDSs where different disinfectants could be blended.

Overlooked Role of Fungi in Drinking Water Taste and Odor Issues.

Taste and odor (T&O) are among the most frequently encountered aesthetic issues in drinking water. While fungi have been reported to produce offensive odors, their contribution to T&O in drinking water remains understudied and often overlooked. In this study, the profiles of fungal community and odorants produced by 10 native fungal isolates were investigated in 36 samples collected from two drinking water treatment plants and a premise plumbing system.

Wavelength dependency and photosensitizer effects in UV-LED photodegradation of iohexol.

Iodinated X-ray contrast media (ICM) are ubiquitously present in water sources and challenging to eliminate using conventional processes, posing a significant risk to aquatic ecosystems. Ultraviolet light-emitting diodes (UV-LED) emerge as a promising technology for transforming micropollutants in water, boasting advantages such as diverse wavelengths, elimination of chemical additives, and no induction of microorganisms' resistance to disinfectants. The research reveals that iohexol (IOX) degradation escalates as UV wavelength decreases, attributed to enhanced photon utilization efficiency.

Insight into mixed chlorine/chloramines conversion and associated water quality variability in drinking water distribution systems.

Mixed chlorine/chloramines are common in drinking water distribution systems (DWDSs); however, their transformation and impact on chemical and microbial characteristics are not well understood. We systematically investigated water quality parameters associated with mixed chlorine/chloramine species conversion in 192 samples (including raw, finished, and tap water) collected throughout the year in a city in East China. Various chlorine/chloramine species (free chlorine, monochloramine [NHCl], dichloramine [NHCl], and organic chloramines [OC]) were detected in both chlorinated and chloraminated DWDSs.

Enhanced 2-MIB degradation by UV-LED/chlorine process: reaction kinetics, wavelength dependence, influencing factors and degradation pathways.

The efficient removal of 2-Methylisoborneol (2-MIB), a typical odour component, in water treatment plants (WTPs), poses a great challenge to conventional water treatment technology due to its chemical stability. In this study, the combination of ultraviolet light-emitting diode (UV-LED) and chlorine (UV-LED/chlorine) was exploited for 2-MIB removal, and the role of ultraviolet (UV) wavelength was investigated systematically. The results showed that UV or chlorination alone did not degrade 2-MIB effectively, and the UV/chlorine process could degrade 2-MIB efficiently, following the pseudo-first-order kinetic model.

Occurrence of fungal spores in drinking water: A review of pathogenicity, odor, chlorine resistance and control strategies.

Fungi in drinking water have been long neglected due to the lack of convenient analysis methods, widely accepted regulations and efficient control strategies. However, in the last few decades, fungi in drinking water have been widely recognized as opportunity pathogens that cause serious damage to the health of immune-compromised individuals. In drinking water treatment plants, fungal spores are more resistant to chlorine disinfection than bacteria and viruses, which can regrow in drinking water distribution systems and subsequently pose health threats to water consumers.