Solar energy for wastewater treatment: review of international technologies and their applicability in Brazil.

Several studies have reported the adverse effects of recalcitrant compounds and emerging contaminants present in industrial effluents, which are not degradable by ordinary biological treatment. Many of these compounds are likely to accumulate in living organisms through the lipid layer. At concentrations above the limits of biological tolerance, these compounds can be harmful to the ecosystem and may even reach humans through food chain biomagnification. In this regard, advanced oxidation processes (AOPs) represent an effective alternative for the removal of the pollutants. This study focused on the AOP involving the use of ultraviolet radiation in homogeneous and heterogeneous systems. Based on the literature review, comparisons between natural and artificial light were established, approaching photoreactors constructive and operational characteristics. We concluded that the high availability of solar power in Brazil would make the implementation of the AOP using natural solar radiation for the decontamination of effluents feasible, thereby contributing to clean production and biodiversity conservation. This will serve as an important tool for the enforcement of environmental responsibility among public and private institutions.

Chemical composition changes in eucalyptus and pinus woods submitted to heat treatment.

This study investigated the influence of heat treatment on the chemical composition of Eucalyptus saligna and Pinus caribaea var. hondurensis woods to understand its role in wood processing. E. saligna and P. caribaea var. hondurensis woods were treated in a laboratorial electric furnace at 120, 140, 160 and 180 degrees C to induce their heat treatment. The chemical composition of the resulting products and those from original wood were determined by gas chromatography. Eucalyptus and Pinus showed a significant reduction in arabinose, manose, galactose and xylose contents when submitted to increasing temperatures. No significant alteration in glucose content was observed. Lignin content, however, increased during the heat process. There was a significant reduction in extractive content for Eucalyptus. On the other hand, a slight increase in extractive content has been determined for the Pinus wood, and that only for the highest temperature. These different behaviors can be explained by differences in chemical constituents between softwoods and hardwoods. The results obtained in this study provide important information for future research and utilization of thermally modified wood.

High temporal, geographic, and income variation in body mass index among adults in Brazil.

OBJECTIVES: Population-based data on body mass index for developing countries are scarce. Body mass index data from two Brazilian surveys were examined to determine regional and temporal variations in the prevalences of underweight, overweight, and obesity. METHODS: Nationwide surveys in 1974/75 and 1989 collected anthropometric data in Brazil from 55,000 and 14,455 households, respectively. Trained interviewers used the same methods to measure weight and stature in both surveys, and survey designs were identical. Prevalences of underweight, overweight, and obesity were determined for persons 18 years of age and older. RESULTS: In the 1989 survey, body mass index varied greatly according to region of the country, urbanization, and income. In the wealthier South, the prevalence of overweight/obesity was the highest and the prevalence of underweight was the lowest; in the poorer rural Northeast, these patterns were reversed. For both surveys, overweight/obesity was more common among women than among men and peaked at age 45 to 64 years in both sexes. Over the 15 years between surveys, the prevalence of both overweight and obesity increased strikingly. CONCLUSIONS: In contrast to findings in developed countries, obesity in Brazil was positively associated with income and was much more prevalent among women than among men. For Brazilian women, the overall prevalence of overweight was nearly as high as that among women in the United States.