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Abstract(s)
Atualmente, a deposição em aterro sanitário é o método mais económico e utilizado na gestão de resíduos sólidos urbanos. Uma consequência inevitável da deposição de resíduos em aterro é a produção de lixiviados, efluentes líquidos resultantes do balanço hídrico dos aterros e da percolação da água na massa de resíduos, que extrai e arrasta consigo diversos materiais dissolvidos e/ou em suspensão. Devido à sua composição, os lixiviados de aterro constituem um importante problema ambiental, com efeitos tóxicos conhecidos. O seu tratamento é um dos maiores desafios na gestão de resíduos sólidos urbanos. Nos últimos anos, a aplicação de processos eletroquímicos no tratamento deste tipo de efluentes tem sido objeto de estudo, com resultados bastante promissores. No entanto, a maioria dos estudos existentes restringe- se apenas à remoção de contaminantes, sendo a influência do tratamento eletroquímico na toxicidade do lixiviado ainda pouco conhecida.
Neste trabalho, foi avaliada a eficiência da oxidação eletroquímica no tratamento de lixiviados de aterro sanitário, quer pela redução de parâmetros físico-químicos, quer pela redução da ecotoxicidade. A toxicidade aguda do lixiviado, antes e depois do tratamento eletroquímico, foi avaliada através do organismo modelo Daphnia magna, recomendado pelas principais organizações internacionais, nomeadamente a American Society for Testing and Materials (ASTM), Organização para Cooperação e Desenvolvimento Económico (OCDE) e Organização Internacional de Normalização (ISO). O tratamento do lixiviado por oxidação eletroquímica mostrou-se eficaz na remoção da carga orgânica e azoto amoniacal, e na redução da concentração de iões metálicos. Além disso, observou-se uma redução de 2,5 vezes na toxicidade aguda para o organismo D. magna após 36 h de tratamento. No entanto, a toxicidade do lixiviado tratado ainda é muito elevada, sendo necessária a aplicação de outros tratamentos para obter um efluente não tóxico para este organismo aquático.
Nowadays, landfilling is the most common and economic way for the disposal of solid wastes. The leachates, formed by the percolation of rainwater, are chemically and biologically complex effluents. Due to its composition, landfill leachates are an important environmental problem with known toxics effects towards wildlife and human health. The efficient treatment of these effluents to effectively eliminate combined toxicity is one of the greatest challenges in waste management. Electrochemical methods appear as an efficient alternative to treat these complex effluents, and they have been subject of study in the past years. However, most of the existent studies only address the removal of contaminants, being the influence of electrochemical treatment in sanitary landfill leachate toxicity not well known. In this study, the efficiency of electrochemical oxidation to treat a sanitary landfill leachate was evaluated by the reduction in physico-chemical parameters and in ecotoxicity. The acute toxicity of the sanitary landfill leachate, before and after treatment, was assessed using the model organism Daphnia magna, a model specie in ecotoxicological tests, recommended by the major international organizations, namely American Society for Testing and Materials (ASTM), Organization for Economic Co-operation and Development (OECD) and International Organization for Standardization (ISO). Electrochemical oxidation treatment showed to be effective in the removal of organic load and ammonium nitrogen, and in the reduction of metal ions concentration. Furthermore, a reduction of 2.5-fold in the acute toxicity towards D. magna after 36 h of treatment was noticed. Nevertheless, the toxicity of the treated leachate is still very high and further treatments are necessary in order to obtain a non-toxic effluent to this aquatic organism.
Nowadays, landfilling is the most common and economic way for the disposal of solid wastes. The leachates, formed by the percolation of rainwater, are chemically and biologically complex effluents. Due to its composition, landfill leachates are an important environmental problem with known toxics effects towards wildlife and human health. The efficient treatment of these effluents to effectively eliminate combined toxicity is one of the greatest challenges in waste management. Electrochemical methods appear as an efficient alternative to treat these complex effluents, and they have been subject of study in the past years. However, most of the existent studies only address the removal of contaminants, being the influence of electrochemical treatment in sanitary landfill leachate toxicity not well known. In this study, the efficiency of electrochemical oxidation to treat a sanitary landfill leachate was evaluated by the reduction in physico-chemical parameters and in ecotoxicity. The acute toxicity of the sanitary landfill leachate, before and after treatment, was assessed using the model organism Daphnia magna, a model specie in ecotoxicological tests, recommended by the major international organizations, namely American Society for Testing and Materials (ASTM), Organization for Economic Co-operation and Development (OECD) and International Organization for Standardization (ISO). Electrochemical oxidation treatment showed to be effective in the removal of organic load and ammonium nitrogen, and in the reduction of metal ions concentration. Furthermore, a reduction of 2.5-fold in the acute toxicity towards D. magna after 36 h of treatment was noticed. Nevertheless, the toxicity of the treated leachate is still very high and further treatments are necessary in order to obtain a non-toxic effluent to this aquatic organism.
Description
Keywords
Ânodo de Diamante Dopado Com Boro Daphnia Magna Lixiviados de Aterro Sanitário Oxidação Eletroquímica Toxicidade Aguda