Scientific and technological developments of the last century undeniably contributed to achieve current lifestyle standards. Yet, such progress also resulted in an undesirable heritage of anthropogenic contaminants that are seriously affecting water quality. That is the case of organic microcontaminants, such as pharmaceuticals, which end up in wastewaters as a result of human and veterinary use (excretion and inadequate disposal). A main route for the entrance of pharmaceuticals in aquatic environments is through effluents from wastewater treatment plants (WWTP) as these are not designed to effectively remove them.
Even though pharmaceuticals are still not object of specific environmental legislation, and despite occurring in aquatic environments at trace levels, there is strong evidence of possible toxicity. Also, an increase in consumption and environmental occurrence is expected due to global population growth and aging.
Thus, upgrading wastewater treatment to ensure the removal of these microcontaminants is a challenge in the context of water management and public health, opening the door to the safe use of treated wastewater for industrial, urban and agricultural applications as a way of facing the extreme droughts and water scarcity that is growing at alarming levels.
Adsorptive removal by activated carbons (AC) has been pointed as a feasible tertiary treatment for the removal of pharmaceuticals from wastewater, and the SYNERGY team has significantly contributed to the knowledge on the production and utilization of alternative and sustainable waste-based AC for this purpose. On the other hand, enzyme mediated degradation of pharmaceuticals has recently emerged as a sustainable and green approach. Yet, each of these treatments face important drawbacks that restrain a more generalized applicability and hamper scalability. The limited regeneration of exhausted AC; and the low operational stability, difficult recuperation from treated water and generation of unknown degradation products derived from enzyme-assisted processes are amongst the most relevant limitations. To overcome these weaknesses, SYNERGY aims to combine the strengths of AC adsorption and enzymatic degradation by developing a carbonaceous enzyme-modified composite for the synergistic removal of pharmaceuticals from water. The existence of possible synergies in the removal of pharmaceuticals between the simultaneous processes occurring in the composite (adsorption and degradation) are expected to highly improve the robustness of this approach in relation to each process individually, namely through the in-situ regeneration of the carbonaceous porous matrix by enzymatic action (extending the materials lifetime) and the adsorption of enzymatic degradation by-products onto vacant adsorption sites (avoiding their release into the treated water). To achieve such goals, and considering sustainability as a priority, waste-based AC will be produced by a one-step microwave-driven chemical activation of brewery spent grains (a major solid residue of brewing industry) and the resulting AC will be subsequently functionalized with oxidoreductase enzymes. The composites will be characterized to select optimal synthesis routes and will be then applied in the removal of pharmaceuticals, both in batch and continuous operation. Yet, a complete and meaningful assessment of the performance of the developed materials must address important key areas that are commonly overlooked in the literature, such as: a) evaluation of the adsorptive-degradation treatment efficiency in real matrices (e.g. wastewater from WWTP) and at environmentally relevant concentrations (in the low ug/L range) to ensure results with practical relevance; b) identification, by mass spectrometry, of enzymatic degradation by-products that might be released into the treated water; c) ecotoxicity assessment of the treated wastewater using freshwater model organisms; d) life cycle assessment (LCA) of the optimized materials to understand the environmental impacts of the studied approach.
To address all the above-mentioned issues, SYNERGY will be divided into 7 interlinked tasks, with 2 tasks devoted to materials production and characterization, 4 tasks dedicated to the comprehensive evaluation of the materials efficiency (from the removal efficiency to the safety of the treated water, resulting in an exhaustive study on applicability of the proposed hybrid adsorption-degradation treatment), and 1 task devoted to LCA of the developed materials. SYNERGY will be developed by a multidisciplinary team of researchers from 3 departments (Chemistry, Environment and Planning, and Biology) and from the 2 largest Associated Laboratories (CESAM & CICECO) of the University of Aveiro, with the international participation of ‘Instituto de Ciencia y Tecnología del Carbono’ and ‘Universidad de Léon’ (Spain), in collaboration with wastewater treatment and brewing industries.
