Resumen de Fungal treatment for the elimination of pharmaceutical compounds from wastewater: chemical, microbiological and ecotoxicological evaluation
During the past years the presence of pharmaceuticals in the environment has attracted the attention of scientific community as well as raised public concern, as they could pose a risk for the environment. Their presence in natural aquatic environment points out to the inability of conventional wastewater treatment plants to eliminate these compounds efficiently. Many research efforts have been devoted in the last years to explore and develop advance and alternative wastewater treatment strategies, able to eliminate pharmaceuticals from wastewater in an efficient and cheap manner. Among all the new technologies studied, fungal treatment of wastewater has been investigated due to the ability of some fungal species to degrade chemical contaminants, including pharmaceuticals. The elimination of these compounds have recently been studied in urban and hospital wastewater as well as in the waste generated in reverse osmosis treatment of wastewater effluents. These studies have been performed at lab-scale but some aspects of the fungal wastewater treatment still need to be addressed before its implementation at full-scale. The ultimate goal of this thesis is to study some of these aspects in order to generate more information about these wastewater technologies concerning removal of emerging pollutants. Therefore, the work presented aims to address the following specific objectives: i) to evaluate pharmaceuticals removal with the fungal treatment from an ecotoxicological point of view, ii) to evaluate the efficiency of the fungal treatment in the elimination of antibiotics, iii) to assess the spread of antibiotic resistance genes during the fungal treatment and iv) to study the relevance of absorption and/or adsorption processes contributing to pharmaceutical removal during fungal treatment. Based on these goals, the work of the thesis is presented in three parts: The first part is dedicated to the general evaluation of removal of pharmaceuticals in different wastewaters and to the ecotoxicological evaluation of those removals. An “Environmental Risk Assessment” is performed for the holistic evaluation of fungal treatment concerning pharmaceutical elimination and the hazard associated.
In the second part, antibiotics removal and antibiotic resistance genes spread is studied jointly in a lab-scale fungal experiment performed with hospital wastewater. Both chemical and microbiological analytical methodologies were used for quantification of antibiotic residues and resistance genes respectively. A possible relationship between antibiotics and antibiotic resistance gene associated was also studied.
The third part deals with the sorption processes taking place during the pharmaceuticals removal: first, in experiments performed with six different fungi for the elimination of selected pharmaceuticals in spiked water, and second in the experiments performed with Trametes versicolor for the elimination of pharmaceuticals present in a veterinary hospital wastewater. Pharmaceutical concentrations in the fungal biomass were also compared with those concentrations commonly measured in sludge from conventional wastewater treatment plants.
The results from this thesis provide valuable information about several aspects of fungal treatment and point it out as a very promising technology for the removal of pharmaceuticals from wastewater effluents.
