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In this work, the influence of bisphenol A (BPA) on biological wastewater treatment was studied. For it, two sequencing batch reactors (SBRs) were operated for three months. Both SBRs were fed with synthetic wastewater (SW), adding 1 mg·L -1 of BPA into the feed of reactor SBR-BPA, while the other one operated without BPA as a control reactor (SBR-B). In addition, batch experiments were performed with adapted and non-adapted activated sludge, simulating the reaction step of SBR-BPA, to determine the pathways for BPA removal. Results of batch experiments showed that adsorption and biodegradation were the only significant BPA removal routes. BPA removal by biodegradation was more efficient when adapted biomass was used in the tests (32.2% and 8.2% with adapted and non-adapted biomass, respectively), while BPA adsorption removal route was similar in both types of activated sludge (around 40%). Regarding the SBRs experiments, after 16 days no BPA concentration was detected in SBR-BPA effluent. In the adaptation process, SBR-BPA biomass was more sensitive to low temperatures resulting in higher effluent turbidity, COD and soluble microbial products concentrations than in SBR-B. However, once temperature increased, adapted biomass from SBR-BPA presented higher activity than SBR-B biomass, showing higher values of sludge production, microbial hydrolytic enzymatic activities and specific dynamic respiration rate. The bacterial community study revealed the increase of abundance of Proteobacteria (especially Thiothrix species) and Actinobacteria (especially Nocardioides species) phyla at the expense of Bacteroidetes and Chloroflexi phyla in SBR-BPA during its operation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Nowadays, alternative options to conventional wastewater treatment should be studied due to rising concerns emerged by the presence of pharmaceuticals compounds (PhCs) in the aquatic environment. In this work, a combined system including biological treatment by activated sludge plus adsorption with activated carbon is proposed to remove three selected drugs (acetaminophen (ACT), caffeine (CAF) and ibuprofen (IBU)) in a concentration of 2 mg L -1 of each one. For it three sequencing batch reactors (SBR) were operated. SBR-B treated a synthetic wastewater (SWW) without target drugs and SBR-PhC and SBR-PhC + AC operated with SWW doped with the three drugs, adding into SBR-PhC + AC 1.5 g L -1 of a mesoporous granular activated carbon. Results showed that the hybrid system SBR-activated carbon produced an effluent free of PhCs, which in addition had higher quality than that achieved in a conventional activated sludge treatment in terms of lower COD, turbidity and SMP concentrations. On the other hand, five possible routes of removal for target drugs during the biological treatment were studied. Hydrolysis, oxidation and volatilization pathways were negligible after 6 h of reaction time. Adsorption route only was significant for ACT, which was adsorbed completely after 5 h of reaction, while only 1.9% of CAF and 5.6% of IBU were adsorbed. IBU was the least biodegradable compound., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The fate and presence of nanoplastics in wastewater treatment systems is a topic of increasing interest. Furthermore, challenges related to their quantification and identification have made it difficult to set up experimental conditions and compare results between studies. In this study, the effect of 100 nm polystyrene nanoplastics on activated sludge was evaluated. A concentration of 2 μg/L was used to continuously feed a sequencing batch reactor (SBR-NPs). Under the experimental conditions used in this study, no changes were observed in the process performance of the SBR-NPs compared to the reactor used as a control. Neither nitrification nor organic matter removal efficiency, which was 96% for both SBRs, were affected by the presence of 100 nm polystyrene nanoplastics, which suggests that the tested nanoplastics were not sufficiently toxic to the biomass. Although no significant differences in the relative abundances of predominant phyla between SBR-Control and SBR-NPs were observed, a slight shift in the relative abundance of Patescibacteria (1.5 ± 0.6% and 3.7 ± 0.8% in SBR-Control and SBR-NPs, respectively, at the end of the test) occurred. The higher abundance of this phylum in SBR-NPs compared to SBR-Control may suggest that these bacteria have some sensitivity to the presence of 100 nm polystyrene nanoplastics. Furthermore, even with the absence of nitrification inhibition, it was observed stagnation of the growth of Nitrotoga bacteria in SBR-NPs, which also suggests that the polystyrene nanoplastics could have an inhibitory effect on these cells and an impact on nitrification in the long term. • Organic matter removal was not affected by 100 nm polystyrene nanoplastics. • Differences between the microbial populations in SBRs (control and with NPs) were found. • Nitrotoga bacteria abundance was reduced in SBR with 100 nm polystyrene nanoplastics. • Nanoplastics enhanced the abundance of Patescibacteria in the activated sludge. • Moderate heteroaggregation of nanoplastics was found in the activated sludge. [ABSTRACT FROM AUTHOR]