Ozonisation coupled with biological degradation for treatment of phenolic pollutants: a mechanistically based study

Phenolic acids constitute an important group of pollutants which are reluctant to biological treatment. Solutions containing a mixture of cinnamic acid, p-coumaric acid, caffeic acid and ferulic acid were submitted to ozonisation. Then, the changes in biodegradability along the process were studied by means of respirometry. There is an optimum ozone dosage in the interval 3-5 min of treatment which allows to achieve the maximum increase in biodegradability (more than 10 times) and a high efficiency of the ozonisation process (COD decreases to a half of its initial value). Further ozonisation does not help to increase biodegradability and is clearly disadvantageous. Similar results are obtained with actual samples of olive oil wastewaters. This behaviour is explained based on the formation of highly biodegradable benzaldehydes as key ozonisation intermediates, in the early reaction stages.     

The European union as first mover in the market for greenhouse gas emissions permits

This study aims to analyse the potential market for emissions permits that the European Union (EU) established in 2005, in a first-mover attitude with regard to the frame of the Kyoto Protocol. To this end the integrated assessment Regional Integrated Climate and the Economy (RICE) model is employed, adapted to the specific objectives intended. A referential paretian-optimum price of US$25.63 tCO₂ is obtained around the year 2007, which duplicates the hypothetical harmonized carbon tax. The ratio between the willingness to pay and the net environmental damages as a result of adverse climate change point to the high degree of commitment and the leadership initiative that seem to be assumed by the EU-15, the extended EU including Eastern European countries and the European OECD as a whole, with the hinterland geo-strategic referent represented by Russia and the Ukraine.     

Reduction of NO by CO using Pd-CeTb and Pd-CeZr catalysts supported on SiO2 and La2O3-Al2O3

The catalytic activity of Pd catalysts supported on Ce_0.73Tb_0.27O_x/SiO₂, Ce_0.6Zr_0.4O_x/SiO₂, Ce_0.73Tb_0.27O_x/La₂O₃-Al₂O₃ and Ce_0.6Zr_0.4O_x/La₂O₃-Al₂O₃ was studied using the reduction of NO by CO. The catalysts were characterized by X-ray fluorescence, surface area, X-ray diffraction, temperature-programmed reduction, CO chemisorption and oxygen storage capacity. Temperature-programmed reduction results indicated that Tb or Zr incorporation improves the reducibility and oxygen storage capacity. CO chemisorption data suggested the presence of large PdO particles due to the low CO/Pd ratio. No significant differences were obtained in light off temperatures (T_{Light off}) for all Pd catalysts and the most active was 1.5%Pd/Ce_0.6Zr_0.4O_x/SiO₂.     

Removal of emerging pollutants in aqueous phase by heterogeneous Fenton and photo-Fenton with Fe2O3-TiO2-clay heterostructures

Environmental Science and Pollution Research - Fe2O3-TiO2-clay heterostructures have been prepared using an organo-bentonite as support, which organophilic character favored the fixation of TiO2....     

Greenhouse gas emissions from a semi-arid tropical reservoir in northeastern Brazil

We estimated carbon dioxide (CO₂) and methane (CH₄) emissions by diffusion, ebullition, and degassing in turbines from a semi-arid hydropower reservoir in northeastern Brazil. Sampling sites were allocated within the littoral and deeper waters of one embayment, the main-stream, and at turbines. Annual carbon emissions were estimated at 2.3?×?10⁵?±?7.45?×?10⁴ t C year^?1, or in CO₂-equivalents (CO₂-eq) at 1.33?×?10⁶?±?4.5?×?10⁵ t CO₂-eq year^?1. Diffusion across the water surface was the main pathway accounting for 96% of total carbon emissions. Ebullition was limited to littoral areas. A slight accumulation of CO₂, but not of CH₄, in bottom waters close to the turbines inlet led to degassing emissions about 8?×?10³ t C year^?1. Emissions in littoral areas were higher than in main-stream and contribute to 40% of the total carbon. Carbon (C) emissions per electricity generated, at 60% of installed capacity, is 0.05 t C-CO₂-eq MWh^?1. The ratio increases to 0.09 t C-CO₂ MWh^?1, equating 80% of the emissions from natural gas and 40% of diesel or coal power plants. Retention time and benthic metabolism were identified as main drivers for carbon emissions in littoral areas, while water column mixing and rapid water flow are important factors preventing CH₄ accumulation and loss by degassing. Our results indicate that Itaparica Reservoir, located in the semi-arid region of Northeastern Brazil, acts as a source of GHGs. Management measurements are needed to prevent emissions to raise in the future.     

Toxic potential of the emerging contaminant nicotine to the aquatic ecosystem

Nicotine is a “life-style compound” widely consumed by human populations and, consequently, often found in surface waters. This fact presents a concern for possible effects in the aquatic ecosystems. The objective of this study was to assess the potential lethal and sublethal toxicity of nicotine in aquatic organisms from different trophic levels (Vibrio fischeri, Pseudokirchneriella subcapitata, Thamnocephalus platyurus, and Daphnia magna). The bioassays were performed by exposing the organisms to concentrations of nicotine in a range of 0.5–1000 μg/L. Results showed that nicotine, at tested concentration, was not acutely toxic to V. fischeri and T. platyurus. On the contrary, this substance exhibited toxicity to P. subcapitata and Daphnia magna. Thus, concentrations of nicotine of 100 and 200 μg/L promoted an inhibition in the growth of P. subcapitata. In addition, a concentration of 100 μg/L nicotine acted on the reproduction of the crustacean D. magna, by decreasing the number of juveniles produced by female. On the other hand, the results showed that concentrations equal to or greater than 10 μg/L induced the production of daphnids male offspring, which may indicate that nicotine is a weak juvenoid compound of the D. magna endocrine system. Furthermore, the result showed that concentrations tested of this chemical have the capacity to revert the effect of fenoxycarb, a strong juvenoid chemical insecticide. The results of the study revealed that nicotine can induce several changes in some of the most important key groups of the aquatic compartment, which can compromise, in a short time, the balance of aquatic ecosystem. Finally, a preliminary environmental risk assessment of this stimulant was performed from the highest measured concentration in surface water and the no observable effect concentration value in the most sensitive species, i.e., D. magna. This process revealed that nicotine can produce an important risk to aquatic organisms.     

Comparison of the energetic performance of a binary cycle and a flash evaporation binary cycle,using low-enthalpy geothermal energy

In this article, the comparison of the energetic performance of a binary cycle and a modified binary cycle with flash evaporation is presented, both using a low-enthalpy geothermal resource. The comparative analysis is based on two main discourses: the first one evaluates a conventional binary cycle (CBC) with isopentane as working fluid in order to validate and compare the generated data with those reported in similar studies; the second one uses the same input parameters for both cycles, obtaining the cases in which the modified binary cycle is the most viable choice to use. In addition to the above, several aspects are considered when selecting the most suitable working fluid, and the use of water as working fluid is introduced. When the temperature of the geothermal resource is below 140 °C, and the ambient temperature is 25 °C, the flash evaporation binary cycle, using water as working fluid, shows an improved performance compared to a CBC, with a theoretical output over 1000 kWe. This may encourage new areas of opportunity for power generation, not only with low- and medium-enthalpy geothermal energy, but also with other renewable energy sources such as solar.     

Emotional,physical, and social needs among 0–5‐year‐old children displaced by the 2010 Chilean earthquake: associated characteristics and exposures

An 8.8‐magnitude earthquake occurred off the coast of Chile on 27 February 2010, displacing nearly 2,000 children aged less than five years to emergency housing camps. Nine months later, this study assessed the needs of 140 displaced 0–5‐year‐old children in six domains: caregiver stability and protection; health; housing; nutrition; psychosocial situation; and stimulation. Multivariate regression was applied to examine the degree to which emotional, physical, and social needs were associated with baseline characteristics and exposure to the earthquake, to stressful events, and to ongoing risks in the proximal post‐earthquake context. In each domain, 20 per cent or fewer children had unmet needs. Of all children in the sample, 20 per cent had unmet needs in multiple domains. Children's emotional, physical, and social needs were associated with ongoing exposures amenable to intervention, more than with baseline characteristics or epicentre proximity. Relief efforts should address multiple interrelated domains of child well‐being and ongoing risks in post‐disaster settings.