Electrooxidation Combined with Ozonation in Hospital Laundry Effluents Treatment

• Published in: Clean : soil, air, water Vol. 42; no. 5; pp. 601 - 608
• Main Authors: Lutterbeck, Carlos Alexandre, de Oliveira Schwaickhardt, Rômulo, Straatmann, Alexandre, Kist, Lourdes Teresinha, Lobo, Eduardo A., Machado, Ênio Leandro
• Format: Journal Article
• Language: English
• Published: Weinheim Blackwell Publishing Ltd 01-05-2014; Wiley Subscription Services, Inc
• Subjects: Effluent treatment; Effluents; Electrooxidation; Hospital laundry effluents; Water pollution
• ISSN: 1863-0650; 1863-0669
• DOI: 10.1002/clen.201200580

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/BOD5) 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/O3 and EO + O3) were used for the treatment tests. The tests involving the EO process for 60 min 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%).
The main objectives of this study involved the decrease of certain load parameters (i.e. BOD5, COD, phosphorus, nitrogen, and surfactants) and the detoxification of the effluents generated by a hospital laundry. To accomplish these goals, certain tests were performed using advanced oxidative processes that involved EO, both alone and in combination with ozonation.