In this article, a novel batch reactor of ultraviolet (UV) light-emitting diodes (LEDs) and peroxydisulfate has been studied for the degradation of Basic Red 46 (BR46) as a model organic pollutant in water. Almost no dye degradation was achieved with UV LED alone, whereas 43% of destruction was obtained in the presence of peroxydisulfate. More than 90% of the dye content was eliminated using UV LED and peroxydisulfate simultaneously in 30 min. Effects of different parameters such as UV LED irradiation, peroxydisulfate concentration, dye concentration, pH, and current on the removal of BR46 were investigated. Satisfactory degradation of BR46 was observed for tested pH range of 2–9.8, with peak at pH 6.43. Electrical energy per order (E_EO) for degradation values of BR46 using both UV LEDs and traditional UV lamps in different concentrations of peroxydisulfate were calculated. Our results show that using LEDs reduces E_EO significantly. On increasing the current from 360 to 2,000 mA, the decolorization rate increased. Hence, 720 mA of current intensity was preferred to avoid consumption of energy. A novel and effective cooling system was installed to increase the lifespan of LEDs and make the system economically more feasible for water and wastewater treatment.

Fires alter terrestrial dissolved organic carbon (DOC) exports into water, making reliable post-fire DOC monitoring a crucial aspect of safeguarding drinking water supply. We evaluated DOC optical sensors in a pair of prescribed burned and unburned first-order watersheds at the Santee Experimental Forest, in the coastal plain forests of South Carolina, and the receiving second-order watershed during four post-fire storm DOC pulses. Median DOC concentrations were 30 and 23 mg L−1 in the burned and unburned watersheds following the first post-fire storm. Median DOC remained high during the second and third storms, but returned to pre-fire concentrations in the fourth storm. During the first three post-fire storms, sensor DOC load in the burned watershed was 1.22-fold higher than in the unburned watershed. Grab samples underestimated DOC loads compared with those calculated using the in-situ sensors, especially for the second-order watershed. After fitting sensor values with a locally weighted smoothing model, the adjusted sensor values were within 2 mg L−1 of the grab samples over the course of the study. Overall, we showed that prescribed fire can release DOC during the first few post-fire storms and that in-situ sensors have adequate sensitivity to capture storm-related DOC pulses in high-DOC forest watersheds.