No abstract

Anaerobic digestion processes with biogas production are widely used for organic waste treatment with an emphasis on energy recovery. Some recent studies have demonstrated the influence of magnetism on microbiological activity. These indicate a possible influence on the efficiency of anaerobic digestion. Thus, technologies that act in anaerobic digestion enhancement can contribute to the improvement of treatment of organic compounds. The present study aimed to verify the influence of a constant electromagnetic field on the anaerobic digestion in anaerobic reactors fed with glucose (2 g/L) at 37 ± 2 °C. In each experiment, reactors were operated with a constant electromagnetic field of 5, 7.5, and 10 mT. The inoculum was granular sludge from an anaerobic treatment plant in a non-selective media culture. Biogas production, chemical oxygen demand (COD), and solids removal were measured during the experiment. Results showed differences in methane production of 21.5% and in COD removal of 15% in the tests with an electromagnetic field of 7.5 mT. These results signs for the viability of the application of a constant magnetic field as a biostimulation agent.

A qualidade dos resultados depende da acurácia dos dados disponíveis. Dados topográficos de todo o globo, provenientes da SRTM - Shuttle Radar Topography Mission, são disponibilizados gratuitamente. Se corretos, estes dados constituem recurso poderoso para o planejamento territorial e ambiental. O objetivo deste trabalho foi verificar o grau de semelhança da informação disponibilizada pela SRTM com outra de maior resolução, aplicada ao modelo EUPS – Equação Universal de Perda de Solo para estimar a perda de solo em uma microbacia em São Carlos, São Paulo, Brasil. A acurácia do MDT SRTM foi avaliada por meio do índice KAPPA que, através de uma matriz de erro, mostra o grau de semelhança entre dois mapas. O índice KAPPA revelou que o MDT SRTM possui um nível de precisão considerado razoável (0.6594) para os mapas de estimativa de perda de solo, entretanto os mapas do fator LS, potencial natural de erosão e estimativa de perda de solo possuem níveis de acurácia considerados baixo (0.2584), baixo (0.2582) e moderado (0.4199), respectivamente. Finalmente, os dados fornecidos pela SRTM apresentaram resultados razoáveis, quando multiplicados por dados de maior resolução em cenários de relevo pouco acidentado. Contudo devem ser utilizados com precaução em outras situações.

This study proposed action scenarios for urban solid waste management in six municipalities in the Corumbataí River Basin. The operating scenarios were designed for organic waste treatment and for the shared disposal of urban solid waste. Six municipalities were studied, five of which had less than 30,000 inhabitants (Analândia, Charqueada, Corumbataí, Ipeúna, and Santa Gertrudes). In addition, Rio Claro had 199,000 inhabitants. Thus, the transport and transshipment stages, general infrastructure, and final disposal in landfills were analyzed. Further, the three scenarios for organic waste treatment were conducted separately. The items and the cost of implementation were estimated for decentralized composting, centralized composting, and biomethanization of waste with electricity recovery. The biomethanization scenario included the commercialization of electricity, so it generated revenues that decreased costs. This cost reduction was especially notable in the last years of the project when the goals of diversion of organic waste through selective collection were higher. The results suggested that the investigated scenarios could improve organic waste treatment and that the biomethanization scenario with electricity generation presented lower average costs per inhabitant than the centralized and decentralized composting scenarios.