The challenge of providing good-quality reclaimed water free from contaminants of emerging concern, even at small concentrations, i.e., microcontaminants (MCs), and pathogens is one of the main hot topics worldwide. UVC-based advanced oxidation processes, using in situ production of strong oxidizing radicals, such as HO˙ and SO₄˙⁻, have shown high oxidation rates for MCs; however, few studies have focused on the simultaneous removal of MCs and pathogens, like bacteria. Thus, the aim of this work was to assess the oxidation of six MCs, acetaminophen (ACT), caffeine, (CAF), carbamazepine (CBZ), trimethoprim (TMP), sulfamethoxazole (SMX), and diclofenac (DCF), in the presence of Escherichia coli, Enterococcus faecalis, and Salmonella enteritidis in a simulated effluent from a municipal wastewater treatment plant by the application of UVC/H₂O₂ and UVC/S₂O₈ ²⁻ processes at pilot plant scale. The concentration of MCs and bacteria was monitored along the oxidation processes as well as their regrowth after 24, 48, and 144 h. UVC-based processes were compared in terms of the required treatment time to remove at least 80% of the sum of MCs, regrowth assessment, and energy consumption. Despite the UVC/H₂O₂ and UVC/S₂O₈ ²⁻ processes showing similar results, even after using distinct molar concentrations, the UVC/H₂O₂ process did not exhibit bacterial regrowth under dark conditions. A simple model has also been proposed in this work with the main objective of calculating the minimum concentration of oxidants as a function of the radiation absorption at 254 nm in a given photo-reactor setup.

Yearly thousands of tons of cellulose, in the form of toilet paper, end up in the wastewater treatment plants (WWTP) through the sewage. Cellulose was recovered with a 0.35 mm sieve and processed obtaining three different pellets: pure cellulose, straw mix (50 % cellulose-50 % straw) and wood mix (50 % cellulose-50 % wood). Those materials were carbonized at 750 °C for 210 min producing non-activated biochar. Then, a part of those biochars was biologically activated by fermentation adding minerals, nutrients and a mixture of bacteria. All biochar versions were characterized, assessing the surface, porosity and adsorption capacity for a dye (indigo carmine) and a selection of 5 micropollutants (MPs): benzotriazole, carbamazepine, clarithromycin, DEET, and diclofenac. However, results showed that conventional analysis for adsorbents was not adequate for biologically activated materials since biofilm can obstruct the pores of the supporting material hindering the pollutants' adsorption. Therefore, the biological degradation of the pollutants by the microorganisms was also tested. Finally, biologically activated WOW-Biochar straw mix was the selected material to be further applied in constructed wetlands (CW) due to its higher average MPs removal capacity. Validation test at mesocosm scale demonstrates the suitability of the material as an admixture in CW, reaching a MPs removal rate higher than the 90 % regarding the WWTP inlet.