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This study assessed the effect of hydraulic retention time (HRT) on biohydrogen production by dark fermentation using an anaerobic fluidized bed reactor fed with cheese whey synthetic wastewater. The reactor of 1.2 L was operated with an approximate carbohydrate concentration of 2800 mg L -1 , and HRTs of 6, 4, 2, 1 and 0.5 h. Acetic and butyric acids were the main metabolites produced in the reactor. The hydrogen production increased from 0.039 to 1.43 L-H 2 h -1 L -1 -reactor as the HRT decreased from 6 to 0.5 h. The best hydrogen yield (HY) (2.73 mol-H 2 mol-carbohydrate -1 ) and carbohydrate consumption (81.02%) were achieved at a HRT of 6 h (12.34 kg-COD m -3 d -1 ) followed by the HY of 2.43 mol-H 2 mol-carbohydrate -1 at a HRT of 0.5h (163.02 kg-COD m -3 .d - 1 ). An increase in the influent pH in the operational phase 05 (HRT of 0.5 h) favored hydrogen production despite the reduced carbohydrate conversion compared to phase 01 (HRT of 6 h). In both conditions, the reactor presented the highest amount of acetic acid, indicating that the acetate route favored the hydrogen yield production. The HRT reduction led to an increase in microbial diversity, as evidenced by the Shannon-Wiener coefficient of 2.586, which corresponds to the operational phase with a HRT of 2 h.

<p class="Default">Nos países industrializados, a descoberta da dimensão do problema da contaminação dos solos e das águas subterrâneas levou à sistematização do gerenciamento de áreas contaminadas. Cerca de cinco anos após a publicação da Resolução CONAMA 420/09, que estabeleceu diretrizes para o gerenciamento de áreas contaminadas no Brasil, foi levantado neste estudo o panorama do país em relacão ao tema. Foram obtidas informações junto aos órgãos ambientais de cada Estado através de consultas aos seus sítios eletrônicos, contatos telefônicos e aplicação de um questionário. Os Estados das regiões sudeste e sul avançaram significativamente no gerenciamento da contaminação do solo. Por outro lado, nas demais regiões do Brasil o gerenciamento de áreas contaminadas ainda é incipiente, e a Resolução CONAMA 420/09 ainda está por ser atendida. Foi realizada uma análise qualitativa do risco causado pela contaminação de solo e água subterrânea em cada unidade da federação, que levou em consideração o nível de gerenciamento praticado e o potencial poluidor existente. Foi encontrado nível de risco alto no Paraná, Santa Catarina, Rio Grande do Sul, Espírito Santo, Distrito Federal, Ceará, Pernambuco e Bahia. Os Estados da região nordeste em acelerado processo de industrialização encontram-se em situação mais crítica, sendo preciso avançar rapidamente no gerenciamento de áreas contaminadas, sob pena de repetirem-se os injustificáveis danos ao meio ambiente e à saúde pública ocorridos nas regiões industrializadas do país em décadas passadas. O avanço do gerenciamento nos Estados brasileiros pode ser alcançado com a criação de leis estaduais específicas e com a evolução do nível técnico dos profissionais que atuam nessa área.</p>

Recreational water quality is commonly assessed by microbial indicators such as fecal coliforms. Maceió is the capital of Alagoas state, located in tropical northeastern Brazil. Its beaches are considered as the most beautiful urban beaches in the country. Jatiúca Beach in Maceió was found to be unsuitable for bathing continuously during the year of 2011. The same level of contamination was not observed in surrounding beaches. The aim of this study was to initiate the search for the sources of these high coliform levels, so that contamination can be eventually mitigated. We performed a retrospective analysis of historical results of fecal coliform concentrations from 2006 to 2012 at five monitoring stations located in the study region. Results showed that Jatiúca Beach consistently presented the worst quality among the studied beaches. A field survey was conducted to identify existing point and non-point sources of pollution in the area. Monitoring in the vicinity of Jatiúca was spatially intensified. Fecal coliform concentrations were categorized according to tide range and tide stage. A storm drain located in northern Jatiúca was identified as the main point source of the contamination. However, fecal coliform concentrations at Jatiúca were high during high tides and spring tides even when this point source was inactive (no rainfall). We hypothesize that high fecal coliform levels in Jatiúca Beach may also be caused by aquifer contamination or, more likely, from tide washing of contaminated sand. Both of these hypotheses will be further investigated.

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