Effect of coupled UV-A and UV-C LEDs on both microbiological and chemical pollution of urban wastewaters

Abstract

Wastewater reuse for irrigation is an interesting alternative for many Mediterranean countries suffering from water shortages. The development of new technologies for water recycling is a priority for these countries. In this study we test the efficiency of UV-LEDs (Ultraviolet-Light-Emitting Diodes) emitting UV-A or UV-C radiations, used alone or coupled, on bacterial and chemical indicators. We monitored the survival of fecal bioindicators found in urban wastewaters and the oxidation of creatinine and phenol which represent either conventional organic matter or the aromatic part of pollution respectively. It appears that coupling UV-A/UV-C i) achieves microbial reduction in wastewater more efficiently than when a UV-LED is used alone, and ii) oxidizes up to 37% of creatinine and phenol, a result comparable to that commonly obtained with photoreactants such as TiO(2).

Using UVC Light-Emitting Diodes at Wavelengths of 266 to 279 Nanometers To Inactivate Foodborne Pathogens and Pasteurize Sliced Cheese

“…Other studies also demonstrated a similar tendency. Chevremont et al (19) treated mesophilic bacteria, fecal enterococci, and coliforms in effluent with UVA and UVC-LED for 60 s. There was only Ͻ1-log reduction, and the inactivation efficacies of 254 and 280 nm were not significantly different. In our study, sterilization efficacy was more related to dose than to wavelength.…”

Assessment of historical fecal contamination in Curitiba, Brazil, in the last 400 years using fecal sterols

“…The use of micro-organisms (e.g., Escherichia coli) to study and confirm domestic sewage contamination in water samples and sediments is limited due to a lack of specificity, light sensitivity (Chevremont et al, 2012), short lifetime, and little resistance to temperature variation (Bebianno and Mudge, 1997;Martins, 2007), making it impossible to study past contaminations.…”

Improved Drinking Water Disinfection with UVC-LEDs for Escherichia Coli and Bacillus Subtilis Utilizing Quartz Tubes as Light Guide

“…A possible way of circumventing the strong absorbance would be to couple UVC with UVA-LEDs. This combination showed increased disinfection results according to Chevremont et al [20].…”

“…The inactivation rate was furthermore determined by dividing the filtered concentration of the initial stock solution N0 by the evaluated bacterial concentration Ni after defined time intervals ti of 10, 40, and 90 s of UVC irradiation. The overall logarithmic inactivation rate was finally determined by calculating log10 [20].…”