The use of ultraviolet light in photoreactors for wastewater treatment has become popular as an alternative of known chemical oxidative substances. UV LED light represents cheaper, robust, and versatile alternative to traditional UV lamps. In this study, it was designed and evaluated a photoreactor with an approach of chemical fluid dynamics (CFD) and experimental validation. The evaluation consisted of (1) CFD velocity profile analysis, (2) characterization of the average light distribution with potassium ferrioxalate actinometry, (3) degradation of a typical recalcitrant metallic cyanocomplex Fe(CN), and (4) scavenger effect analysis in the photodegradation using potassium persulfate. Actinometrical essay concluded that the system was able to receive 1.93 μE/s. The reactor operated under turbulent regime and best result for Fe(CN) degradation was obtained at 4 h of operation, using 5-W UV-A LEDs, with pH ~ 7 and 10 mM de SO. Baffled photoreactor demonstrated to be useful for this type of illumination and wastewater treatment.

The effluents of the sugar and bio-ethanol industry, mainly vinasse as well as lignocellulosic waste, are produced in high volumes. Therefore, their treatment and valorization would reduce the environmental impact and make this industry more productive and competitive. The purpose of this study was to determine the potential use of press mud (lignocellulosic waste), vinasse powder, and vinasse sludge from an extraction process with ethanol, as raw materials for conventional pyrolysis evaluating the physicochemical characteristics that affect this thermochemical process, such as calorific power, density, ash content, volatile material, moisture and nitrogen, sulfur, carbon and hydrogen content, thermogravimetric profile, and quantification of lignin cellulose and hemicellulose. The batch pyrolysis experiments showed that all three wastes could be converted successfully into more valuable products. The powder vinasse led to the formation of the lowest content of bio-char (42.7%), the highest production of volatiles (61.6 wt.%), and the lowest ash content (20.5 wt.%). Besides, it showed the high heating value of 15.63 MJ/kg. Meanwhile, the extraction sludge presented the highest liquid yield (32%) with the lowest gas formation (18.2 wt.%) and the lowest heating value of 8.57 MJ/kg. Thus, the sludge could be a good feedstock for production of bio-oil and bio-char.