ABSTRACT
RESUMO: Nesse trabalho, objetivou-se recuperar o óleo presente na borra oleosa por processo de extração, a fim de reutilizá-lo como combustível. Foram aplicados dois planejamentos experimentais: fatorial fracionado e Doehlert. Através da caracterização da borra oleosa (análises físico-químicos, elementar CHN e S, orgânicas e inorgânicas), constatou-se que a borra oleosa utilizada é constituída de 36,2% de óleo, 16,8% de cinzas, 40% de água e 7% de compostos voláteis. A eficiência média do processo de extração foi 70%. Entretanto, a análise estatística mostrou que o modelo quadrático não se ajustou bem ao processo, devido à complexidade do material estudado. Por outro lado, aplicando-se a modelagem de RNA, o coeficiente de determinação foi de 87,5%, mostrando-se bastante satisfatório.
ABSTRACT: This work aimed to recover the oil present in oily sludge by extraction process in order to reuse it as fuel. Two experimental designs were applied: fractional factorial and Doehlert. Through characterization of the oily sludge (physico-chemical analysis, CHN and S elemental, inorganic and organic), it was found that the oily sludge used consists of 36.2% oil, 16.8% ash, 40% water and 7% volatile compounds. The efficiency obtained in the oil extraction process was 70%, in average. However, statistical analysis showed that the quadratic model did not satisfactorily the process due to the complexity of the studied material. By the other hand, applying ANN the coefficient of determination became 87.5% that is quite satisfactory.
ABSTRACT
Over the past few decades, a high number of pharmaceuticals have been detected in surface, ground and drinking waters. This contamination comes from domestic sewage, livestock, hospitals and chemical-pharmaceutical industries. Typical examples of these pollutants are the fluoroquinolones - powerful antibiotics used in human and veterinary medicine. The presence of fluoroquinolones in the environment can pose a serious threat to the ecosystem and to human health due to their high consumption globally: in 1998, around 120 tons were produced. Even at low environmental concentrations, antibiotics stimulate bacterial resistance. The consequences of the presence of fluoroquinolones in the environment are not fully understood, but are known to be toxic to plants and aquatic organisms. Approximately 85% of the fluoroquinolones present in influents can be removed by conventional wastewater treatment plants, but the removed fraction is frequently accumulated in the sludge, which is sometimes used as fertilizer, representing an additional input route into the environment. The removal of fluoroquinolones by biological treatment is ineffective, and it is believed that only advanced oxidation technologies are able to destroy these emerging pollutants.
Nas últimas décadas, um grande número de fármacos tem sido identificado em águas superficiais, subterrâneas e potáveis. Tal contaminação advém do esgoto doméstico, hospitais, criação de animais e das indústrias químico-farmacêuticas. Exemplos típicos desses poluentes são as fluoroquinolonas – potentes antibióticos empregados na medicina humana e veterinária. A presença de fluoroquinolonas no meio ambiente pode representar uma séria ameaça para o ecossistema e para a saúde humana devido ao alto consumo mundial: em 1998 foram produzidas, aproximadamente, 120 toneladas. Mesmo em baixas concentrações, antibióticos podem estimular a resistência bacteriana. As consequências da presença de fluoroquinolonas no ambiente não são completamente compreendidas, mas sabe-se que são tóxicas para plantas e organismos aquáticos. Aproximadamente 85% das fluoroquinolonas presentes em efluentes podem ser removidos em estações de tratamento de efluentes convencionais, porém a fração removida é frequentemente acumulada no lodo, muitas vezes usado como fertilizante, o que representa uma rota adicional de entrada desses compostos no ambiente. A remoção de fluoroquinolonas por meio de tratamento biológico não é eficiente, e acredita-se que somente as tecnologias de oxidação avançada sejam capazes de degradar esses poluentes emergentes.
Subject(s)
/analysis , Fluoroquinolones/toxicity , Water Pollutants/toxicity , Environmental Pollution/analysisABSTRACT
The photochemical degradation of agrochemicals in aqueous solution by means of advanced oxidation processes (AOPs) was studied. The photo-Fenton process was evaluated in terms of the time evolution of dissolved organic carbon (COD) and chemical oxygen demand (DOC), their total removals, and increase in biodegradability of treated wastewater. Under the experimental conditions studied, the process showed to be superior to other AOPs, at any Fe(II) and H2O2 concentrations. The results pointed towards the use of solar irradiation and low cost commercial application.