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- Intermittent load of 2-fluorophenol in saline wastewater shapes aerobic granular sludge microbiome and reactor performancePublication . Oliveira, Ana S.; Amorim, Catarina L.; Loosdrecht, Mark C. M. van; Castro, PaulaIndustrial effluents often contain organic pollutants and variable salinity levels, making their treatment challenging. Aerobic granular sludge (AGS) is an innovative and compact wastewater treatment technology for the treatment of domestic and industrial water streams. The high content of extracellular polymeric substances (EPS) in AGS composition is thought to protect , to some extent, the microbial communities from stressful conditions in external environment. This work aimed to evaluate the robustness of AGS systems in terms of nutrient removal performance and to unravel the protective role of EPS towards transient feeding with a toxic pollutant (2-fluorophenol - 2-FP) in saline wastewater. Moreover, the taxonomic and functional patterns of the AGS microbiome were characterized and linked with nutrient removal performance and EPS production. In order to mimic transient states of composition typical of industrial effluents, the reactor inlet medium periodically varied regarding to 2-FP presence and salt concentration.
- Biological removal processes in aerobic granular sludge exposed to diclofenacPublication . Bessa, Vânia S.; Moreira, Irina S.; Loosdrecht, Mark C. M. van; Castro, Paula M. L.Diclofenac is a worldwide consumed drug included in the watch list of substances to be monitored according to the European Union Water Framework Directive (Directive 2013/39/EU). Aerobic granular sludge sequencing batch reactors (AGS-SBR) are increasingly used for wastewater treatment but there is scant information on the fate and effect of micropollutants to nutrient removal processes. An AGS-SBR fed with synthetic wastewater containing diclofenac was bioaugmented with a diclofenac degrading bacterial strain and performance and microbial community dynamics was analysed. Chemical oxygen demand, phosphate and ammonia removal were not affected by the micropollutant at 0.03 mM (9.54 mg L-1). The AGS was able to retain the degrading strain, which was detected in the sludge throughout after augmentation. Nevertheless, besides some adsorption to the biomass, diclofenac was not degraded by the augmented sludge given the short operating cycles and even if batch degradation assays confirmed that the bioaugmented AGS was able to biodegrade the compound. The exposure to the pharmaceutical affected the microbial community of the sludge, separating the two first phases of reactor operation (acclimatization and granulation) from subsequent phases. The AGS was able to keep the bioaugmented strain and to maintain the main functions of nutrient removal even through the long exposure to the pharmaceutical, but combined strategies are needed to reduce the spread of micropollutants in the environment.
- Simultaneous nitrification and phosphate removal by bioaugmented aerobic granules treating a fluoroorganic compoundPublication . Duque, Anouk F.; Bessa, Vânia S.; Dongen, Udo van; Kreuk, Merle K. de; Mesquita, Raquel B. R.; Rangel, Antonio O. S. S.; Loosdrecht, Mark C. M. van; Castro, Paula M. L.The presence of toxic compounds in wastewater can cause problems for organic matter and nutrient removal. In this study, the long-term effect of a model xenobiotic, 2-fluorophenol (2-FP), on ammonia-oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB) and phosphate accumulating organisms (PAO) in aerobic granular sludge was investigated. Phosphate (P) and ammonium (N) removal efficiencies were high (>93%) and, after bioaugmentation with 2-FP degrading strain FP1, 2-FP was completely degraded. Neither N nor P removal were affected by 50 mg L−1 of 2-FP in the feed stream. Changes in the aerobic granule bacterial communities were followed. Numerical analysis of the denaturing gradient gel electrophoresis (DGGE) profiles showed low diversity for the ammonia monooxygenase (amoA) gene with an even distribution of species. PAOs, including denitrifying PAO (dPAO), and AOB were present in the 2-FP degrading granules, although dPAO population decreased throughout the 444 days reactor operation. The results demonstrated that the aerobic granules bioaugmented with FP1 strain successfully removed N, P and 2-FP simultaneously.