This study is the first environmental comparison between a UV-C LED lamp (emitting at 265 nm) and mercury lamps employed in a lab-scale photoreactor for water treatment purification purposes, using the removal of diclofenac as a case study. Ex-ante life cycle assessment (LCA) methodology was used as a robust method to identify hotspots and recommendations at the early stage of the UV-C LEDs technology. The functional unit was defined as "the treatment of 1 L of polluted water with 20 mg L-1 of diclofenac to achieve a 90% removal of the contaminant", while the system boundaries include the production and the operation of the photoreactors, following a cradle-to-gate approach. Several scenarios were explored, and overall, the UV-C LED lamp shows a promising environmental performance, with less or similar potential impacts than the mercury lamps in the 16 categories selected from the Environmental Footprint (EF) method. In particular, it reveals less impact in "human toxicity non-cancer" and "resource use minerals and metals" and presents electricity as the main source of impact. Given the higher efficacy of the UV-driven advanced oxidation processes compared to the UV irradiation alone, and since no studies have previously been conducted on the sustainability of free chlorine (FC) as an oxidant in water treatment, a comparison between UV-C, UV-C/H2O2, and UV-C/FC while employing the 265 nm UV-C LED lamp was also assessed. UV-C/H2O2 was more sustainable than UV-C/FC for the same treatment time, but both led to an overall impact reduction of 35% and 30%, respectively. To increase sustainability, employing cleaner energy sources such as photovoltaic or wind energy also resulted in an 80% and 93% reduction in the "climate change" category. Overall, this study demonstrates that using UV-C LEDs and the selected oxidants for water purification is beneficial and encourages the scale-up of the system.

Accurately modelling the propagation of radiant intensity in aqueous environments poses significant challenges for both academia and industry, due to complex interactions like absorption, scattering, and reflection. This study aims to improve the accuracy of optical modeling in water-based systems by comparing experimental data with numerical simulation techniques, addressing the need for more reliable simulation methods in multiple applications like treatment of water and environmental monitoring.Implementation has been done by analyzing how the method compares with the discrete ordinate method, radiometry, and actinometry. The study further quantifies the effect of the photoreactor quartz tube on measured intensity for multiple wavelengths. Losses in light intensity are estimated to be 10 ± 0.5% for FX-1 265 source. In contrast, the simulation in a water medium showed an increase of up to 64% in the light intensity delivered to the central part of the tube due to internal reflections and scattering. Model predictions from ray tracing successfully compared with the Discrete Ordinate Method (DOM) and experimental data (within ± 6%), ensuring the accurate design of complex systems for water disinfection. The data from simulations is seen to tackle challenges faced in complex radiation modeling and demonstrates that the method can be utilized as a useful tool for optimization and prediction.

Background Measurement of light intensity reaching a point of interest in complex systems is a challenge faced by academia and industry. This study analyzes an optical ray tracing method to predict the radiant intensity reaching a point of interest in a germicidal system. Methods Implementation was performed by analyzing how the method compares with the discrete ordinate method, radiometry, and actinometry. This study further quantified the effect of the photoreactor quartz tube on the measured intensity for multiple wavelengths. Results Light intensity losses were estimated to be 10 ± 0.5% for the FX-1 265 source. In contrast, the simulation in a water medium showed an increase of up to 64% in the light intensity delivered to the central part of the tube owing to internal reflections and scattering. Model predictions from ray tracing were successfully compared with the discrete ordinate method (DOM) and experimental data (within ± 6%), ensuring the accurate design of complex systems for water disinfection. Conclusions The data from simulations address the challenges faced in complex radiation modeling and demonstrate that the method can be utilized as a useful tool for optimization and prediction.

Access to safe water is a growing global concern, with millions lacking acceptable water sources. Photocatalysis offers eco-friendly water remediation, yet its combination with electrocatalysis for both water treatment and hydrogen production remain underexplored. This study investigates UVA LED photoelectrocatalysis using WO3-based photoanodes, alone or in heterojunction with BiVO4, to purify wastewater and co-produce hydrogen. Tests on polluted water streams containing 105 PFU mL-1 of MS2 bacteriophage virus and 106 CFU mL-1 of E. coli reveal that nanostructured WO3 achieves rapid MS2 disinfection within 5min. (k= 0.80min-1), with enhanced efficiency over flat counterparts. However, nanostructuring does not improved E. coli inactivation due to bacterium size constrains. These findings advance the design of tandem photoreactors for dual wastewater purification and energy generation.

Dataset of paper "Removal of diclofenac by UV-B and UV-C light-emitting diodes (LEDs) driven advanced oxidation processes (AOPs): Wavelength dependence, kinetic modelling and energy consumption" Molar absorption coefficient of the DCF (pH 7.2), FC (pH 8.5), and H2O2 (pH 6.5) in the wavelength range of 200-400 nm. Time-based and UV fluence-based kinetic constant and synergy factor for the DCF degradation. Diclofenac degradation fitted by the proposed models (UV/H2O2 and UV/FC). Oxidant degradation fitted by the proposed models (UV/H2O2 and UV/FC).

This study explores and analyses the kinetic and mechanistic aspects of microfiltration cellulose acetate mem-brane fouling by polyamide (PA) and polystyrene (PS) particles in dead-end configuration and the main in-teractions between the microplastics and the membrane during the filtration process. First, PA and PS particles were characterised to define the differences in shape (regular and irregular), particle size distribution (10-105 mu m and 20-320 mu m), and surface charge (neutral and negative). The results showed that the prevailing mech-anisms during microplastic filtrations were complete pore blocking followed by cake layer formation in both cases. The mechanisms' kinetics were positively correlated to MPs load through a power-law relationship which was stronger for PS than for PA particles because of higher steric hindrance effects. On the other hand, increasing the working transmembrane pressure led to an optimum working condition, between 0.3 and 0.5 bar for PA and 0.3 bar for PS filtration. Overall, higher fouling was induced by the PA particles due to the higher PA hydro-phobicity and their smaller size, which caused a denser cake layer. Instead, PS particles with higher irregularities and repulsive electrostatic forces formed a more porous layer but induced a high degree of abrasion on the membrane surface. Finally, membrane fouling led to an increase in hydrophobicity and roughness, probably causing further fouling. To conclude, modelling membrane fouling can help predict the best working conditions and the membrane replacement cycles to increase the MPs removal efficiency and reduce secondary MP-based pollution.

Uniform illumination from UVA LED lamps is a crucial design characteristic for a range of industries including photocatalytic applications. In this work, radiometry and the discrete ordinate method (DOM) are used to determine the ideal target surface size and working distance from a UVA LED lamp for highly uniform illumination. Horizontal incident radiation and full surface incident radiation measurements were conducted using a scanning radiometry technique. It is shown that horizontal incident and full surface incident radiation measurements show good agreement for uniformity measurements over a range of working distances, with maximum uniformity (2.6% and 3.6% standard deviation respectively) over the measured range found at 15 mm working distance. DOM simulation results showed good agreement with radiometry for power and incident radiation measurements, whilst indicating a maximum uniformity at 20 mm working distance. These results demonstrate that DOM simulations can be used as a fast, low cost, and reliable indication of surface uniformity, peak surface irradiance, and power measurements in the design of UV lamps for industrial and academic applications.

Dataset of paper "Wavelength synergistic effects in continuous flow-through water disinfection systems"

It is accepted that Microplastic (MP) biofilms accumulates antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) in water. ARB/ARGs and MPs are emerging pollutants of concern due to various associated health risks. The objective of this study was to 1) investigate the ARB community in a pilot-scale wastewater treatment plant (WWTP) effluent, 2) to study and visualize the ARB/ARGs in MP biofilm grown in WWTP effluent and tap water, and 3) to analyze microplastic adherent ARB/ARGs in the biofilm and planktonic ARB/ARGs in the filtrate under controlled conditions. Results indicated the dominance of Pseudomonas, Aeromonas, and Bacillus among isolated ARB in WWTP effluent. Representative resistance strains were incubated in 300 mL water containing commercial polystyrene beads of 300550 μm diameter (MP) in a series of batch experiments. Microbiological, molecular, and microscopic analyses were performed by enumeration, 16srRNA, real-time polymerase chain reaction (qPCR), and Field Emission-Scanning Electron Microscopy (FEG-SEM) techniques. The analyzed viable ARB indicated an increasing trend in MP biofilms between days 3 and 5. It further decreased on days 7 and 9. The prevalence of ARB in the filtrate and MP biofilm varied as a function of time and TOC level, while no significant impacts were observed for minor temperature variation, low antibiotic pressure, and increased MP mass with few exceptions. Relative abundance of ARGs (vanA, sul1) and integron integrase gene (intl1) in MP biofilm were significantly different across different TOC levels, time, and antibiotic pressure. ARGs and intl1 were detected in the MP biofilm in tap water and WWTP effluent on day 30.

Measurement of light output from ultraviolet (UV) light-based devices is critical to understanding the capability of the device. Optical sensors such as radiometers and dosimeters can possess different angular responses and are sensitive to many parameters in the measurement set-up. This work has been designed to quantify the effect of multiple parameters on the measurements obtained from optical sensors to provide inputs for validating measured data for ultraviolet sources. Multiple light sources operating in the ultraviolet range have been measured and a comparison between different sensors is presented. The angular response has been evaluated for each detector and compared with an ideal cosine response. Two of the six sensors studied displayed a near cosine response. A change of angle of acceptance with wavelength was observed for the ThorLabs S120VC and ILT W Optic diffuser. Due to use of artificial heating, the effect of measured intensities on the sensor as a function of temperature was seen to be insignificant but provided an understanding of how temperature of the sensor can influence measured data. Finally, the effect of ambient light and the integration time on the measured data were investigated. The effect of ambient light proved to be significant, when not considered in measurement of low light signals sources while the effect of choosing an ideal integration time has been seen to impact the mea-surements obtained. A measured difference of 43% was observed between a saturated and unsaturated sensor.

Increasing antibiotic resistance and microplastic (MP) pollution are among the global environmental challenges of our time. This study reviews relevant studies on MP pollution and the abundance of antibiotic resistant elements in freshwater resources. The objective was to evaluate the potential antibiotic resistance spread via MPs in the freshwater aquatic environment. Studies have indicated that MPs interact with microbial communities differently than natural particles, harboring a unique bacterial community than the surrounding water. The composition of MP biofilm community revealed an abundance of bacterial cells, pathogens, antibiotic resistant genes (ARGs) and mobile genetic elements (MGEs). The closely packed bacterial cells in MP biofilm in a water matrix might offer a favorable enviroment for horizontal genes transfer (HGT). Furthermore, antibiotics in trace concentrations in freshwater resources could be adsorbed onto MP surfaces and impact the microbial composition by selective enrichment of antibiotic resistant bacteria (ARB). The biofilm matrix provide protection in MP biofilms that could impact the disinfection efficiency of conventional treatment techniques. The impacts of MPs, antibiotic resistant elements and their interaction on human health and aquatic biota remain relatively unknown to date. Future studies on MPs and antibiotic resistant elements need to consider the collective role, challenges, and consequences of the interaction between MPs and antibiotic resistant elements in freshwater ecosystem.

The ubiquitous presence of microplastics (MPs) in the environment has become a major challenge in recent years. One of the main concerns is the eco-toxicological effect on marine ecosystems and the potential threat for human organs and tissues. This paper focuses on evaluating membranes performance in removing MPs within a simple, low-cost system that could be easily implemented in a domestic environment. The performance of polycarbonate, cellulose acetate, and polytetrafluoroethylene membranes with the same nominal pore size of 5 ​μm was evaluated in the removal of polyamide and polystyrene microparticles in the range of 20–300 ​μm. Their mass removal efficiency when filtering 100 ​mg/L of MPs was also calculated. A high mass removal efficiency of MPs above 94 was obtained with the three membranes. However, depending on the MPs’ nature, they could either break through the membrane or break down into smaller particle sizes. Beside size-exclusion separation, the main competing mechanisms are membrane abrasion and fouling phenomenon. Their contribution depends on the membrane properties, MPs-membrane interaction, particles’ irregularity, and transmembrane pressures employed. At comparable mass removal efficiency, the highest performing membrane material for long-term household system applications was found to be cellulose acetate.