-Wastewater treatment by deactivated and activated sludge was investigated to evaluate the removal of estrogens [estrone (E1), 17β-estradiol (E2), 17α-ethinylestradiol (EE2)] via adsorption and degradation. Different treatment conditions were used, including three mixed liquor volatile suspended solid (MLVSS) concentrations, three methanol concentrations (carbon source) and three types of aqueous media (water, synthetic solution, and supernatant). The E2 was degraded the fastest by the bacterial community. In all cases the removal rate increased when the initial MLVSS and methanol concentrations increased and when the macro-and micronutrients were present in the solution. In the experiments with deactivated sludge, the synthetic compound EE2 was more easily removed via sorption. The bacterial communities of the activated sludge were studied, which indicated a similarity of more than 75% between the different samples. A similarity of only 50% was found between the activated and deactivated sludges.

A B S T R A C TThis study aimed to evaluate the performance of a sequencing batch membrane bioreactor (SBMBR) in wastewater treatment for nutrient removal. The reactor, which was built at a pilot scale with a volume of 15 L, was operated for 240 d and fed with municipal wastewater. The SBMBR was operated under a sequencing batch mode, with a total cycle time of 4 h, including the feeding, anoxic/anaerobic, and aeration/filtration phases. The membrane bioreactor presented high performance on chemical oxygen demand, ammonium, and total nitrogen removal during the whole experimental period, with average removals efficiencies of around 97, 99, and 82%, respectively. Regarding total phosphorus, SBMBR reached the average removal efficiency of 48%. The poor phosphorus removal performance was attributed to the low availability of organic matter during the anoxic/anaerobic phase due to denitrification activity, which limited the P-release process and subsequent P-uptake during aerobic phase. Furthermore, the temperature increase during the summer period further hindered the enhanced biological phosphorus removal process, in which a decrease in the P-release values was observed. Fluorescence in situ hybridization analysis revealed a large presence of glycogen-accumulating organisms population on the SBMBR sludge, which contributes to explain the low efficiency obtained in phosphorus removal.

This study evaluated the removal of organic matter, nitrogen and phosphate from a municipal wastewater in a sequencing batch membrane bioreactor (SBMBR) operated at different solids retention times (SRTs) and subjected to different aeration profiles. The results demonstrated that SRT reduction from 80 to 20 d had a negligible effect on chemical oxygen demand (COD) removal and only a slight negative effect on nitrification. COD removal efficiency remained stable at 97%, whereas ammonium removal decreased from 99% to 97%. The total nitrogen removal efficiency was improved by SRT reduction, increasing from 80% to 86%. Although the total phosphorus (TP) removal was not significantly affected by the SRT reduction, ranging from 40-49%, the P-release and P-uptake processes were observed to increase as the SRT was reduced. The implementation of a pre-aeration phase in the SBMBR operating cycle allowed a higher TP removal performance, which reached up to 76%. Batch tests suggested that the fraction of phosphate removed anoxically from the total (anoxic + aerobic) phosphate removal decreased with the SRT reduction.

This study aims to use electrodes modified with bismuth films for the determination of zinc and cadmium. The film was electrodeposited ex situ on a composite carbon electrode with polyurethane and 2% metallic bismuth (2BiE) and on a carbon bar electrode (CBE). The electrodes were characterized by scanning electron microscopy and energy dispersive spectroscopy. Through differential pulse anodic stripping voltammetry, the electrodes 2BiE and CBE containing bismuth films showed a limit of detection (LOD) of 5.56 × 10 -5 and 3.07 × 10 -5 g.L -1 for cadmium and 1.24 × 10 -4 and 1.53 × 10 -4 g.L -1 for zinc, respectively. The presence of a bismuth film increased the sensitivity of both electrodes.

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