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- Removal of fluoxetine and its effects in the performance of an aerobic granular sludge sequential batch reactorPublication . Moreira, Irina S.; Amorim, Catarina L.; Ribeiro, Ana R.; Mesquita, Raquel B. R.; Rangel, António O.S.S.; Loosdrecht, Mark C.M. van; Tiritan, Maria E.; Castro, Paula M. L.Fluoxetine (FLX) is a chiral fluorinated pharmaceutical mainly indicated for treatment of depression and is one of the most distributed drugs. There is a clear evidence of environmental contamination with this drug. Aerobic granular sludge sequencing batch reactors constitute a promising technology for wastewater treatment; however the removal of carbon and nutrients can be affected by micropollutants. In this study, the fate and effect of FLX on reactor performance and on microbial population were investigated. FLX adsorption/desorption to the aerobic granules was observed. FLX shock loads (<= 4 mu M) did not show a significant effect on the COD removal. Ammonium removal efficiency decreased in the beginning of first shock load, but after 20 days, ammonia oxidizing bacteria became adapted. The nitrite concentration in the effluent was practically null indicating that nitrite oxidizing bacteria was not inhibited, whereas, nitrate was accumulated in the effluent, indicating that denitrification was affected. Phosphate removal was affected at the beginning showing a gradual adaptation, and the effluent concentration was <0.04 mM after 70 days. A shift in microbial community occurred probably due to FIX exposure, which induced adaptation/restructuration of the microbial population. This contributed to the robustness of the reactor, which was able to adapt to the FLX load.
- Effects of fluoxetine schock loadings in a aerobic granular sludge sequencing batch reactorPublication . Moreira, Irina S.; Ribeiro, Ana R.; Amorim, Catarina L.; Mesquita, Raquel B. R.; Rangel, António O. S. S.; Tiritan, Maria E.; Castro, Paula M. L.Pharmaceuticals have received increasing attention as emerging organic pollutants due to their frequent occurrence in the environment and potential adverse effects on ecossistems and to human health. Pharmaceuticals may not be completely metabolized in the human body and can enter municipal sewage systems as the parent drug and as their “biologically active” metabolites. Some of these compounds cannot be easily removed at wastewater treatment plants (WWTPs) [1]. Fluoxetine (FLX) is a chiral fluorinated pharmaceutical indicated mainly for treatment of depression and is one of the most dispensed drugs in the world. There is a clear evidence of environmental contamination with this drug and its active metabolite norfluoxetine (NFLX) [2]. Granular sludge sequencing batch reactors (SBR) constitute a promising technology for the treatment of effluents containing micropollutants. The main biological processes occurring in wastewater treatment plants - COD, N and P removal - can be inhibited by these pollutants. This study focused on the effect of FLX on the performance of granular sludge SBR and on the diversity of the microbial population under continuous and intermittent feeding of the compound. The COD removal was not markedly affected by FLX shock loads. Ammonium removal was initially affected but after ca. 20 days of FLX feeding, NH4+ was not detected in the treated effluent – maximum of 0.03 mM – indicating that ammonia oxidizing bacteria (AOB) became adapted to the presence of FLX. Nitrite was also practically not detected in the treated effluent - maximum of 0.01 mM - indicating that nitrite oxidizing bacteria (NOB) were not inhibited by the presence of the FLX, whereas nitrate accumulated in the effluent, indicating that denitrification was affected. Phosphate removal was markedly affected in the beginning of FLX feeding showing a gradual adaptation to the presence of FLX, being practically not detected in the treated effluent (maximum of 0.04 mM) after 70 days. There was no evidence of FLX biodegradation. Changes in the bacterial community from aerobic granules were examined using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA. Samples taken before starting the shock loadings with FLX clearly shift from other samples. Moreover, two main branches separate the samples taken during continuous FLX feeding from samples taken during intermittent FLX feeding.
- Aerobic granular sludge sequencing batch reactor performance under fluorinated pharmaceuticals shock loadingsPublication . Moreira, Irina S.; Amorim, Catarina L.; Ribeiro, Ana R.; Maia, Alexandra S.; Mesquita, Raquel B. R.; Calheiros, Cristina S. C.; Rangel, António O. S. S.; Loosdrecht, Mark C. M.; Tiritan, Maria E.; Castro, Paula M. L.The widespread usage of pharmaceuticals is of increasing concern. Aerobic granular sludge sequencing batch reactors (AGS-SBR) constitute a promising technology for the treatment of wastewaters, however how the removal of carbon and nutrients can be affected by such micropollutants is largely unknown. This study evaluates the impact of different fluorinated drugs (ofloxacin, norfloxacin, ciprofloxacin and fluoxetine) on the performance of an AGS-SBR. During 468 days, a sequence of intermittent, alternating and/or continuous shock loads of pharmaceuticals were apllied to an AGS-SBR and the effects on the main biological processes were evaluated. Here we report on the effect of fluoroquinolones on reactor performnce. The organic removal, measured by COD, was not markedly affected by pharmaceuticals shock loads. Ammonium and nitrite were practically not detected in the bioreactor effluent indicating that the presence of the pharmaceuticals did not inhibit nitrification, whereas accumulation of nitrate in the effluent was observed, indicating that denitrification was affected. Phosphate removal was affected to some extent. There was no evidence of biodegradation whereas adsorption of the target pharmaceuticals to the AGS was observed, which were gradually released into the medium after withdrawal from the inlet stream.