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Background Unregulated use of veterinary pharmaceuticals has caused environmental concerns such as ecotoxicity and development of genetic resistance in the microbial biosphere. Photocatalytic treatments, e.g. photo‐Fenton reaction, have been considered for their removal. In this work, substitution of the use of a chemical oxidant such as hydrogen peroxide (Fenton reaction) by organic molecules from sonicated microalgae biomass Chlorella sp, combined with Fe2+ and UV light, was used to evaluate the removal of antibiotic ciprofloxacin (CIP) and hormone 17β‐estradiol (E2) in synthetic wastewater. Results Removal of CIP was improved using only UV (71%), by adding Fe2+ at 0.54 mmol L−1 (90.17%) and combining these with sonicated microalgae biomass (0.4 g L−1), achieving >99% CIP removal and 75% E2 removal after 120 min of treatment. When the conditions were optimized, aiming to decrease the Fe2+ concentration and improve the removal of CIP, the optimal conditions were pH 7, sonicated microalgae biomass concentration 0.5 g L−1 and 0.39 mmol L−1 Fe2+, reaching 97 and 70% removal efficiency for CIP and E2 respectively; when microalgae biomass was not added, removal decreased to 90 and 57% respectively. Conclusion Photodegradation with sonicated microalgae biomass has demonstrated to be an effective option to improve the removal of selected antibiotics and hormones from wastewater, considering that no acidification or costly reagents are needed for its optimization. © 2020 Society of Chemical Industry

Phenolic compounds are toxic and dangerous to the environment and human health. Although the removal of phenols and their derivatives is very difficult, it has been achieved by applying some biological processes. The capacity of microalga to remove phenolic compounds has been demonstrated; however, few reports of the removal of these compounds in a mixture have been published. The removal of phenol, p-cresol and o-cresol was performed by batch kinetics at 50 and 100 mg L−1, and the simultaneous degradation of phenol, p-cresol and o-cresol was carried out in a mixture at 40 mg L−1 using the marine microalga Tetraselmis suecica. The kinetic study was carried out for 192 h. For concentrations of 50 mg L−1 and 100 mg L−1, phenolic compound consumption efficiencies greater than 100% and 85%, respectively, were obtained, and up to 73.6% removal in the mixture. The results obtained indicate that the marine microalga carries out a process of the oxidation of organic matter and phenolic compounds, mineralizing up to 31.4% to CO2 in the mixture. Biological treatments using the marine microalga T. suecica can be considered feasible to treat effluents with concentrations similar to those of the present study.