Tratamento anaeróbio de efluentes líquidos industriais: alguns pontos focais

Esta comunicação aborda os fundamentos bioquímicos e microbiológicos que condicionam a concepção de reactores anaeróbios para tratamento de efluentes líquidos industriais e, complementarmente, apresenta vários aspectos referentes ao projecto de sistemas anaeróbios indicando alguns factores da opção aerobiose/anaerobiose, principais tipos de reactores e uma menção a aplicações industriais conhecidas

Mass transfer coefficients within anaerobic biofilms effects of external liquid velocity

This work concerns mass transport in anaerobic biofilms, formed under upflow liquid velocities similar to the prevailing conditions in anaerobic reactors used for wastewater treatment. During biofilm formation under liquid velocities of 1.5 and 13.2 m/h, internal mass transfer coefficients were routinely measured. Mass transfer coefficients attained pseudo steady-state values between 2-4 x 10ˉ³ m/h, no dependence being observed between bulk flow and internal mass transport rates. However, a transient variation in the liquid velocity from 1.5 up to 13.2 m/h, imposed after the biofilm had reached the steady-state, increased the internal mass transport by 20% on average. This result suggests that periodic changes in the bulk fluid velocity can be used as a tool to increase the transport of soluble substrates inside already formed biofilms, although the effect seems to be limited.Fundação para a Ciência e a Tecnologia (FCT) - PRAXIS XXI (2/2.1/BIO/37/94). European Commission

Environmental technology education in Portugal : analysis and perspectives

The scope of the present communication is the current status of environmental engineering in Portugal. The different approaches concerning the environmental engineering courses available at undergraduate levels as well as some post-graduation studies are described. Furthermore, an analysis based on strengths, weakness, opportunities and trend issues regarding the environmental engineering profession in Portugal is presented

Search for associations containing young stars (SACY). V. Is multiplicity universal? Tight multiple systems

Context: Dynamically undisrupted, young populations of stars are crucial to study the role of multiplicity in relation to star formation. Loose nearby associations provide us with a great sample of close ($<$150 pc) Pre-Main Sequence (PMS) stars across the very important age range ($\approx$5-70 Myr) to conduct such research. Aims: We characterize the short period multiplicity fraction of the SACY (Search for Associations Containing Young stars) accounting for any identifiable bias in our techniques and present the role of multiplicity fractions of the SACY sample in the context of star formation. Methods: Using the cross-correlation technique we identified double-lined spectroscopic systems (SB2), in addition to this we computed Radial Velocity (RV) values for our subsample of SACY targets using several epochs of FEROS and UVES data. These values were used to revise the membership of each association then combined with archival data to determine significant RV variations across different data epochs characteristic of multiplicity; single-lined multiple systems (SB1). Results: We identified 7 new multiple systems (SB1s: 5, SB2s: 2). We find no significant difference between the short period multiplicity fraction ($F_\mathrm{m}$) of the SACY sample and that of nearby star forming regions ($\approx$1-2 Myr) and the field ($F_\mathrm{m}\leq$10%) both as a function of age and as a function of primary mass, $M_1$, in the ranges $P$ [1:200 day] and $M_2$ [0.08 $M_{\odot}$-$M_1$]. Conclusions: Our results are consistent with the picture of universal star formation, when compared to the field and nearby star forming regions (SFRs). We comment on the implications of the relationship between increasing multiplicity fraction with primary mass, within the close companion range, in relation to star formation.Comment: 14 pages, 18 figures, published, A&A http://dx.doi.org/10.1051/0004-6361/20142385

Fate of protozoa during the start-up of a sequencing batch biofilm reactor used for the degradation of hydrocarbons

Large amounts of oily sludges are retained in patrol stations by gravity interceptors in order to prevent their discharge in surface waters. Those residues are mainly composed of a mixture of hydrocarbons, water and inert solids. Therefore, their final disposal represents a significant environmental problem. This work concerns the study of microfauna biomass during the start-up of a SBBR designed for the treatment of hydrocarbon slurries retained in an API oil separator. The findings of this study suggest that protozoal colonization of the SBBR followed the same pattern of activated sludge systems, the free swimming and crawling ciliates, and also fagellates being the dominant protozoa group during the star-up period of the reactor. When the plant performance dropped, the number of flagellated protozoa rapidly increased, and a concomitant decrease in the ciliated population was observed.Fundação para a Ciência e a Tecnologia (FCT)

Effect of the surfactants tween 20 and CTAB on fluoranthene and anthracene degradation by P. putida

The effect of a nonionic and a cationic surfactant, Tween 20 and CTAB, on the biodegradation rate of fluoranthene and anthracene by a P. putida strain was investigated. Tween 20 had a positive effect on the biodegradation rate of anthracene. However, it did not affect significantly fluoranthene oxidation. The cationic surfactant CTAB inhibited the oxidation of both PAHs, fluoranthene and anthracene

Search for associations containing young stars (SACY). VI. Is multiplicity universal? Stellar multiplicity in the range 3-1000 au from adaptive-optics observations

Context. Young loose nearby associations are unique samples of close (<150 pc), young (approx 5-100 Myr) pre-main sequence (PMS) stars. A significant number of members of these associations have been identified in the SACY collaboration. We can use the proximity and youth of these members to investigate key ingredients in star formation processes, such as multiplicity. Aims. We present the statistics of identified multiple systems from 113 confirmed SACY members. We derive multiplicity frequencies, mass-ratio, and physical separation distributions in a consistent parameter space, and compare our results to other PMS populations and the field. Methods. We have obtained adaptive-optics assisted near-infrared observations with NACO (ESO/VLT) and IRCAL (Lick Observatory) for at least one epoch of all 113 SACY members. We have identified multiple systems using co-moving proper-motion analysis and using contamination estimates. We have explored ranges in projected separation and mass-ratio of a [3-1000 au], and q [0.1-1], respectively. Results. We have identified 31 multiple systems (28 binaries and 3 triples). We derive a multiplicity frequency (MF) of MF_(3-1000au)=28.4 +4.7, -3.9% and a triple frequency (TF) of TF_(3-1000au)=2.8 +2.5, -0.8% in the separation range of 3-1000 au. We do not find any evidence for an increase in the MF with primary mass. The estimated mass-ratio of our statistical sample (with power-law index gamma=-0.04 +/- 0.14) is consistent with a flat distribution (gamma = 0). Conclusions. We show further similarities (but also hints of discrepancies) between SACY and the Taurus region: flat mass-ratio distributions and statistically similar MF and TF values. We also compared the SACY sample to the field (in the separation range of 19-100 au), finding that the two distributions are indistinguishable, suggesting a similar formation mechanism.Comment: 16 Pages, accepted in A&A 28 May 201

Search for associations containing young stars (SACY) VII. New stellar and substellar candidate members in the young associations

The young associations offer us one of the best opportunities to study the properties of young stellar and substellar objects and to directly image planets thanks to their proximity ($<$200 pc) and age ($\approx$5-150 Myr). However, many previous works have been limited to identifying the brighter, more active members ($\approx$1 M$_\odot$) owing to photometric survey sensitivities limiting the detections of lower mass objects. We search the field of view of 542 previously identified members of the young associations to identify wide or extremely wide (1000-100,000 au in physical separation) companions. We combined 2MASS near-infrared photometry ($J$, $H$, $K$) with proper motion values (from UCAC4, PPMXL, NOMAD) to identify companions in the field of view of known members. We collated further photometry and spectroscopy from the literature and conducted our own high-resolution spectroscopic observations for a subsample of candidate members. This complementary information allowed us to assess the efficiency of our method. We identified 84 targets (45: 0.2-1.3 M$_\odot$, 17: 0.08-0.2 M$_\odot$, 22: $<$0.08 M$_\odot$) in our analysis, ten of which have been identified from spectroscopic analysis in previous young association works. For 33 of these 84, we were able to further assess their membership using a variety of properties (X-ray emission, UV excess, H$_\alpha$, lithium and K I equivalent widths, radial velocities, and CaH indices). We derive a success rate of 76-88% for this technique based on the consistency of these properties. Once confirmed, the targets identified in this work would significantly improve our knowledge of the lower mass end of the young associations. Additionally, these targets would make an ideal new sample for the identification and study of planets around nearby young stars.Comment: 28 pages, 24 figures, accepted in A&

Remoção de DQO, nitrogênio e sólidos de reator de lodos ativados no pós-tratamento de dejetos de suínos.

Projeto/Plano de Ação: 02.07.60.700-0