Nanofiltration combined with ozone-based processes for the removal of antineoplastic drugs from wastewater effluents

Over the past years, there has been an increasing concern about the occurrence of antineoplastic drugs in water bodies. The incomplete removal of these pharmaceuticals from wastewaters has been confirmed by several scientists, making it urgent to find a reliable technique or a combination of techniques capable to produce clean and safe water. In this work, the combination of nanofiltration and ozone (O3)-based processes (NF + O3, NF + O3/H2O2 and NF + O3/H2O2/UVA) was studied aiming to produce clean water from wastewater treatment plant (WWTP) secondary effluents to be safely discharged into water bodies, reused in daily practices such as aquaculture activities or for recharging aquifers used as abstraction sources for drinking water production. Nanofiltration was performed in a pilot-scale unit and O3-based processes in a continuous-flow column. The peroxone process (O3/H2O2) was considered the most promising technology to be coupled to nanofiltration, all the target pharmaceuticals being removed at an extent higher than 98% from WWTP secondary effluents, with a DOC reduction up to 92%. The applicability of the clean water stream for recharging aquifers used as abstraction sources for drinking water production was supported by a risk assessment approach, regarding the final concentrations of the target pharmaceuticals. Moreover, the toxicity of the nanofiltration retentate, a polluted stream generated from the nanofiltration system, was greatly decreased after the application of the peroxone process, which evidences the positive impact on the environment of implementing a NF + O3/H2O2 process

Natural Purification Through Soils: Risks and Opportunities of Sewage Effluent Reuse in Sub-surface Irrigation

Graphical Abstrac

Metabolism of Pharmaceuticals in Plants and Their Associated Microbiota

With the increasing use of wastewater for irrigation of farmland, and thus the potential uptake and translocation of pharmaceuticals and their metabolites in crops, concerns about food safety are growing. After their uptake, plants are able to metabolize drugs to phase I, phase II, and phase III metabolites. Phase I reactions closely resemble those encountered in human drug metabolism, including oxidations, reductions, and hydrolysis. Phase II reactions, in turn, encompass conjugations with glutathione, carbohydrates, malonic acid, and amino acids. In phase III, these conjugates are transported and stored in the vacuole or bound to the cell wall. Pharmaceutical metabolism in plants has been investigated by using different approaches, namely, the use of whole plants grown in soil or hydroponic cultures, the use of plant tissues, and the incubation of specific plant cell suspensions. While studies relying on whole plants require long growth periods and more complex analytical procedures to isolate and detect metabolites, they constitute more realistic scenarios with the ability to determine site-specific metabolism and the translocation within the plant. The advantage of in vitro studies lies in their rapid setup. Recent advances in plant-microbiota investigations have shown that the plant microbiome modulates the response of the plant towards pharmaceuticals. Rhizospheric and endophytic bacteria can directly contribute to pharmaceutical metabolism and influence plant uptake and translocation of pharmaceuticals and their metabolites. Additionally, they can have beneficial properties for the host, contributing to plant health and fitness. This chapter gives an overview of human and plant drug metabolism followed by a comparison of different models used to identify pharmaceutical metabolites and their metabolic pathways in plants. A description of the mechanisms and reactions originating these metabolites is concisely presented. Finally, the role of the microbiome is critically discussed with examples of synergies between plants and their associated microbiota for pharmaceutical degradation.Peer reviewe