AbstractIn water treatment process ozone is applied to disinfection and to remove organic pollutants. Membrane contactor devices are used as a physical barrier to separate two fluids without phase dispersion and it can be used to improve the ozonation efficiency. Polymeric materials are used in membrane contactors and they can react with ozone, suffering degradation and losing its mechanical properties. In this work, commercial polymeric membranes were selected to investigate their interaction with ozone in gaseous phase. It was evaluated changes in polymer structures and in membrane morphology by FTIR, DSC, TGA and SEM. It was observed preferential ozone attack to double carbon-carbon bonds in the main polymer chain for polyimide and polysulphone membranes. Polypropylene has single carbon-carbon bonds and its reaction with ozone was less intensive. For polydimethylsiloxane membranes the ozone attack seems to occur in the carbon-silicon bond, leading to loss of mechanical and thermal properties.

O lixiviado de aterros de resíduos sólidos urbanos é uma complexa mistura de substâncias orgânicas e inorgânicas, que em sua composição causam danos ao meio ambiente, devido à elevada concentração de matéria orgânica recalcitrante e à toxicidade presente. A proposta deste trabalho envolve a aplicação dos processos oxidativos avançados (POA), como tratamento de lixiviado oriundos de dois aterros sanitários, Gericinó (Rio de Janeiro/RJ) e Gramacho (Duque de Caxias/RJ), dois aterros com mais de 30 anos de operação, sendo que o último encontra-se encerrado há 2 anos. O objetivo da utilização dos POA é melhorar a qualidade do lixiviado para um tratamento biológico subsequente, para isso foi utilizado o ensaio com a bactéria Aliivibrio fischeri para avaliação da toxicidade. Para o Processo Fenton-escuro, realizado em escala de bancada, nos experimentos realizados a pH=3,0 e razão Fe+2:H2O2 igual a 1:5 foram obtidas remoções de 56% e 19% de DQO para os lixiviados oriundos de Gericinó e Gramacho, respectivamente. Para o Processo Foto-Fenton Solar, realizado em uma planta piloto, nos testes a pH=3,0 e razão Fe+2:H2O2 igual a 1:5, foram alcançadas 88% e 78% de remoção de DQO. Essas condições permitiram uma diminuição da toxicidade dos lixiviados para valores de coeficiente de efeito igual a 50% (CE 50%) para Aliivibrio fischeri maior que 50%, indicando um lixiviado mais adequado para tratamento biológico posterior.

The leachate from municipal solid waste landfills is a complex mixture of organic and inorganic substances, which can damage the environment due to toxicity and the high concentration of recalcitrant organic matter. This work applied advanced oxidation processes (AOP) to the treatment of leachate from the Gericinó (Rio de Janeiro / RJ) and Gramacho (Duque de Caxias / RJ) landfills. These landfills were both in operation for more than 30 years; the latter closed two years ago. The purpose of using AOP is to improve the leachate quality prior to a subsequent biological treatment. The bacteria Aliivibrio fischeri was used as a biological process for evaluation of toxicity. The Dark-Fenton Process employed in bench scale experiments with a pH of 3.0 and Fe+2:H2O2 ratio = 1:5 resulted in removals of 56% and 19% for COD leachate of the Gericinó and Gramacho leachates, respectively. The Solar Photo-Fenton Process conducted in pilot plant tests at pH = 3.0 and Fe+2:H2O2 ratio = 1:5 generated COD removal 88% and 78%, respectively. These conditions led to a decrease in the toxicity of leachates' coefficient values to a degree equal to 50 % - for Aliivibrio fischeri greater than 50% - indicating a more suitable leachate for further biological treatment.