Isabel Cristina A. A. Moura

Ecotoxicity tests in the environmental analysis of wastewater treatment plants: case study in Portugal.

A global evaluation of wastewaters should include ecotoxicological tests to complement the chemical characterization, with advantages especially in the case of complex wastewaters. A European project developed in Trancão River Basin (Portugal), integrated the ecotoxicological and physicochemical studies of wastewater samples from two municipal sewer networks and respective wastewater treatment plants. Wastewater samples were analysed for physicochemical parameters, ecotoxicological acute and chronic tests performed and the potential for endocrine disruption evaluated. Organic load parameters and total suspended solids showed significant correlations with Microtox and ThamnoToxKit test results. Data analysis showed that treated treatment plant effluent samples are associated with less organic contamination and less toxicity in ThamnoToxKit test. Chronic toxicity test and endocrine disruption assay of treatment plant effluent samples indicated that, in a long term, potential population effects could arise in the receiving waters. A test battery to monitor this type of wastewaters is proposed, including tests with a bacterium, an alga and a crustacean. In a screening phase the most sensitive test, Microtox, can be used. The use of an ecotoxicological approach can have added value to hazard and risk assessment of discharges to the receiving waters and can contribute to the environmental management of the treatment plant.

Ecotoxicological assessment of industrial wastewaters in Trancão River Basin (Portugal)

It is important to assess the toxicity of complex effluents, since chemical evaluation alone is insufficient to protect the environment. Direct Toxicity Assessment is valuable in the decision process regarding the final disposal of complex wastewaters as it measures the total effects of the discharge, because of its known and unknown chemicals, additionally having some degree of ecological relevance. In Portugal, ecotoxicity tests are not used on a regular basis to control wastewaters. So, an integrated ecotoxicological, physical, and chemical study of wastewaters from 17 industries, in the Trancão River Basin, was carried out viewing proposing a test battery to be used in wastewater evaluation. An approach which does not include an ecotoxicological characterization may not properly evaluate the potential risks of effluent discharges, especially when they are complex. From the study carried out the use of a battery of assays to apply in the monitoring of complex wastewaters was proposed, including Microtox test, Daphnia test, and an algal test. Moreover, the added value of the ecotoxicological assessment of industrial wastewaters was demonstrated and could support the implementation of EU Directives (e.g. IPPC, WFD) within the Portuguese situation.

Teaching a CS introductory course: An active approach

Computer Science (CS) introductory courses that are offered by the Department of Information Systems at the University of Minho (UM), Portugal, seem to abound in non-motivated students. They are characterized by high failure and withdrawal rates and use mainly deductive teaching approaches. Deductive instruction begins with theories and progresses to applications of those theories. Active approaches to teaching are more inductive. Inductive instruction begins with the presentation of, for instance, a specific problem that introduces a topic, and theories are studied on a need-to-know basis. This pilot study describes how active learning techniques have been successfully applied to a CS introductory course, reducing its failure and withdrawal rates. The study portrays the changes in the course from teacher-centered education to a learner-centered approach, using two different editions of the same course, the first one being teacher-centered and the second learner-centered. The results in terms of success, failure, and dropout are given and the impact of a more student-centered approach on student involvement in learning is analyzed. The authors discuss implications of student-centered learning for the classroom and pay attention to some of the drawbacks of an implementation more focused on active learning.

Synthesis of Biodegradable Copolymers Based on Ethylene Vinyl Acetate and Polylactic Acid

In the present study biodegradable copolymers of ethylene vinyl acetate and polylactic acid were synthesized using transesterification reactions, the structure, morphology, mechanical properties and biodegradability of the produced materials were characterized. Ethylene vinyl acetate was modified with polylactic acid in an internal mixer using titanium propoxide as transesterification catalyst. The graft copolymers were characterized by elemental analysis, infrared spectroscopy, rheology, scanning electron microscopy and thermal analysis. Selective extractions for all copolymers were made, and the results indicate that a maximum of 25 % of EVA-g-PLA copolymer was synthesized by this method. Biodegradation tests were carried out using the standard ISO 14851 (1999), which specifies a method for determining the biochemical oxygen demand in a closed respirometer. This procedure allowed to synthesize biodegradable copolymers with mechanical properties similar to conventional polymers.

8 – Polymeric materials for metal sorption from hydric resources

Abstract Pure water is crucial for global population. However, a wide range of industrial activities contribute to its pollution. Among the pollutants, heavy metals are of high concern. Thus, it is crucial remove these pollutants from water for the population consumption. Several physical and chemical methods, such as chemical precipitation, filtration, coagulation, membrane processes, ion exchange, and adsorption are already being employed in the removal of metal ions from water. This chapter will focus on the adsorption process, which is a highly efficient method that provides flexibility in the design and is easy to operate. Polymeric adsorbents emerged as potential alternatives to activated carbon, the most-used adsorbent. Special emphasis will be given to polymeric materials that are being reported as adsorbents of metal ion, with high emphasis to those derived from natural wastes.

Preparation of biodegradable materials by reactive extrusion

This work aimed to prepare biodegradable polymeric materials based on blends of a synthetic high density polyethylene (HDPE) and biodegradable polymers such as polylactic acid (PCL) and poly(caprolactone) (PLA), in a co-rotating twin-screw extruder. A polyethylene modified with maleic anhydride was used as compatibiliser. The mechanical results showed that the addition of PLA improves the blends stiffness while the addition of PCL leads to materials with a greater elongation at break and a lower Young modulus. This feature is related with the mechanical properties of each material as well as the adhesion between them. Concerning the biodegradability tests, it was found that HDPE/PCL blend presents the highest degree of biodegradability.

High Performance Teams: Do Perceptions and Reality Match?

Effective team management is one of the key factors that allow companies to tackle the challenges of todays demanding business environment. Although high-performing teams have been studied for some time, very little has been written on them from the construction industrys perspective. Based on the conclusions of previous work and on a project involving 44 professionals of seven teams, this exploratory case study intends to evaluate if there is a gap between what team members and leaders perceive as being a the most important features for managing teams into high performance and b the features that are present in their teams. The present study shows that, although teams under investigation had some high-performing features at the leadership dimension, there is room for improvement, in particular when it comes to empowering team members, involving them in planning the work, and creating proper reward systems.