Electrooxidation Combined with Ozonation in Hospital Laundry Effluents Treatment

In the present study, treatment tests were performed on effluents generated from a hospital laundry using electrooxidation (EO) processes. Global parameter analyses and toxicological analyses were conducted before and after each trial. The analytical characterization of the effluent fractions from the hospital laundry revealed variable toxicities ranging from slightly toxic for the composite sample and extremely toxic for the Wash stage. Another parameter related to refractoriness at different currents involved measuring the chemical oxygen demand/biochemical oxygen demand (COD/BOD ₅) ratio, and a maximum ratio of 34.72 was observed in effluents from the wash stage. Ozonation, EO processes with iron electrodes alone, and combined with ozonation (EO/O ₃ and EO+O ₃) were used for the treatment tests. The tests involving the EO process for 60min with induced conductivity through the addition of NaCl exhibited the best performance. Considering the best performance in previous assays, only the electrochemical methods were evaluated with the toxicological analyses. The application of the three-electrochemical methods provided detoxification levels that improved to moderately or slightly toxic. In one of the conditions, the effluent generated in the initial rinse of the linens improved from the condition of extremely toxic (12.58%) to moderately toxic (61.59%), while the COD decreased by 9%. With respect to the effluent coming from the wash step, the COD showed a 41% reduction, while the toxicity was reduced considerably from the condition of extremely toxic (6.89%) to slightly toxic (76.65%).