www.futurenviro.es | Abril-Mayo April-May 2022 63 Aguas Residuales Hospitalarias | Hospital Wastewater En los efluentes analizados se detectaron setenta y nueve fármacos diferentes. Entre ellos, destacan familias de fármacos habitualmente prescritos como reguladores de lípidos y estatinas para reducir el colesterol, antagonistas de los receptores de histamina H1 y H2, diuréticos, agentes betabloqueantes, antihipertensivos, antibióticos, analgésicos y compuestos antiinflamatorios (Figura 1). Los resultados obtenidos indican que el proceso de oxidación Fenton intensivo es el proceso más eficaz para la eliminación de todos los fármacos, con una reducción casi completa respecto de la carga inicial (99,8%). Todos los fármacos fueron completamente eliminados en este tratamiento, excepto citalopram, trazodona y losartán, que aparecieron en el efluente final en concentraciones insignificantes (4,0, 7,5 y 8,5 ng L-1, respectivamente). El proceso fotoFenton eliminó el 94,5% de la carga farmacéutica total, donde solo se detectó acetaminofén a una concentración relevante en el efluente. En el caso del proceso CWAO, se logró una eliminación del 90% de la concentración farmacéutica inicial, detentándose acetaminofén, ciprofloxacina y ofloxacina en el efluente en concentraciones relevantes. Se evaluó, además, el riesgo ambiental de los compuestos y metabolitos farmacéuticos de las muestras de aguas hospitalarias tratadas. Esta evaluación es muy interesante porque considera lipid-lowering agents and cholesterol-lowering statins, histamine H1- and H2-receptor antagonists, diuretics, betablockers, antihypertensives, antibiotics, analgesics and anti-inflammatory compounds (Figure 1). The results obtained indicate that intensified Fenton oxidation is the most efficient process for the removal of all drugs, with an almost total reduction of pharmaceuticals with respect to the initial load (99.8%). All drugs were completely removed in this treatment, except for citalopram, trazodone and losartan, which appeared in the final effluent at negligible concentrations (4.0, 7.5 and 8.5 ng L-1, respectively). The Photo-Fenton process removed 94.5% of the total pharmaceutical load, with only acetaminophen being detected in significant concentrations in the effluent. The CWAO process achieved 90% removal of the initial pharmaceutical concentration, with significant concentrations of acetaminophen, ciprofloxacin and ofloxacin remaining in the effluent. The environmental risk (ΣHQ) of pharmaceutical compounds and metabolites in the treated hospital water samples was also evaluated. This evaluation is of great interest because it takes into account the ecotoxicity of each pharmaceutical product in order to estimate its potential individual effect on the environment. The intensified Fenton process was the most efficient, with a lower final ∑HQ of 5.4. The catalytic wet air oxidation (CWAO) and Photo-Fenton systems, which achieved similar values in terms of organic load reduction of the wastewater, showed very different total ∑HQ values of 895 and 88, respectively. The HQ reductions obtained after these two treatments (∑HQCWAO 895 and ∑HQfoto-fenton 88) indicate that, although the CWAO and Photo-Fenton processes achieved similar initial drug load removals, the environmental impact of the final effluent depends not only on the concentration of the pharmaceutical compounds, but mainly on which compounds are removed and which of those still present have higher risks for the environment. The CWAO process did not achieve total removal of compounds of higher environmental risk (such as antibiotics) so that the subsequent discharge of the treated effluent into a natural watercourse may cause a higher environmental impact. Figura 1. Condiciones y tratamientos de las tecnologías CWAO, Fenton y fotoFenton empleadas para el tratamiento de un agua residual hospitalaria. Figure 1. Conditions and CWAO, Fenton and Photo-Fenton technologies used for the treatment of hospital wastewater.
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