Combined use of VUV and UVC photoreactors for the treatment of hospital laundry wastewaters: Reduction of load parameters, detoxification and life cycle assessment of different configurations

The present research investigated the treatment of hospital laundry wastewaters by the combined use of photochemical VUV and UVC reactors. Seven different configurations were tested and the performances of each of them were evaluated based on the removal of the load parameters, detoxification and life cycle assessment (LCA). The characterization of studied wastewaters included analysis of the following parameters: COD, BOD₅, TKN, total P, pH, turbidity and conductivity. Acute ecotoxicity was evaluated using Daphnia magna. Ultraviolet–Visible (UV–Vis) spectroscopy was performed to determine the organic fraction and chromatography coupled to the mass spectrometer (GC–MS) was used for the qualitative characterization of priority pollutants. Characterization parameters showed the presence of drugs like lidocaine and dipyrone and a high organic load with a poor biodegradability. Wastewaters presented an extreme acute toxicity against D. magna (EC₅₀ 6.7%). The ozonation process (mainly generated by the VUV reactor) obtained the best results concerning the ratio between the consumed energy and the removed COD and the UVC process presented the lowest environmental impacts for the characterization and normalization parameters of the LCA. Normalization revealed that the highest environmental burdens were associated with human toxicity, ecotoxicity and eutrophication of surface waters as well as to the use of non-renewable resources. VUV/UVC/O₃ process presented the best results considering detoxification (EC₅₀ 100%). - Highlights: • Hospital laundry wastewaters are characterized by high organic load associated with toxicity. • New VUV/UVC/O₃ unit configurations were tested to treat hospital laundry wastewaters. • Performances were evaluated based on reduction of load parameters, ecotoxicity and LCA. • O₃ showed the best BOD₅/COD ratio and VUV/UVC/O₃ completely eliminated the toxicity. • LCA highest impacts were related to human toxicity, freshwater eutrophication and ecotoxicity.