We investigated the use of dissolved air flotation (DAF) to treat clear water effluent from the paper industry in order to remove fibers. The dosage of polyaluminium chloride (PAC) was varied in the following concentrations: 0, 75, 100, 125, 150 and 175 mg/L; as well as bubble rise velocity of 18 and 9 cm/min for two types of paper wastewater: print and gloss. Data were statistically analyzed through factorial arrangement 6x2x2. The treatment of the print paper effluent showed better performance in removing the analyzed parameters with an optimal dosage of 100 mg/L PAC, whereas the gloss paper effluent treatment had satisfactory removal of analyzed parameters with an optimal dosage of 150 mg/L of PAC. This led to the observation that the high efficiency directly obtained with the DAF in conjunction with the use of PAC coagulant was an excellent primary treatment option for effluent resulting from the paper industry.
The levels of pollution in water bodies are directly related to the health and welfare of the population that uses this water with different purposes. Events such as vegetation suppression, different uses (industrial, agricultural and domestic), sewage discharge, are some of the factors that mostly contribute to the depletion of such water resources, mainly in urban areas. The objective of this study was the physicochemical monitoring of the urban stretch Arroio dos Pereiras, located in Irati (Parana State, Brazil), in areas of low and medium human occupation. The relations between superface water quality and the use of urban soil in that region were also verified employing high resolution orbital images. The water quality parameters analyzed included pH, total solids, turbidity, dissolved oxygen (DO), biochemical oxygen demand (BOD), total and fecal coliforms (E. coli). The water in Arroio dos Pereiras presented, for most parameters, characteristics which were in accordance with the Brazilian Federal Legislation; however, total and fecal coliforms values were high above limits permitted by law, making the water unsuitable for use. The sewage discharge along the stretch evaluated was the main reason for the low quality of this water.
RESUMOAs indústrias de celulose e papel apresentam grande consumo de recursos naturais, estando entre as que mais produzem efluentes no setor industrial. Devido a esta problemática,várias tecnologias estão sendo utilizadas para o tratamento deste efluente. Portanto, propõe-se neste trabalho a utilização do coagulante natural Tanino no tratamento do efluente de uma indústria de papel, através do processo de coagulação/floculação/decantação, com a finalidade de se verificar sua eficiência de remoção dos parâmetros: turbidez, cor aparente, cor verdadeira, demanda química de oxigênio (DQO), sólidos totais e sólidos suspensos. No processo de tratamento foram utilizadas dosagens de 100, 125, 150, 175 e 200 mg.L -1 de tanino.Os parâmetros operacionais adotados no jar-test foram: gradiente de mistura rápida de 550 s -1 e tempo de mistura rápida de 10 segundos para coagulação; gradiente de mistura lenta de 40 s -1 e tempo de mistura lenta de 15 minutos para floculação e velocidade de sedimentação de 0,4 cm.min . Sendo assim, utilizando-se da dosagem ótima obteve-se remoção de 88%, 83%, 60% e 46% para turbidez, cor aparente, cor verdadeira e DQO respectivamente. Observou-se no estudo que o tratamento foi eficiente quando empregado como alternativa de pré tratamento, uma vez que o mesmo não alcançou valores elevados de remoção de matéria orgânica.
PALAVRAS-CHAVE:Coagulante natural. Ensaios de coagulação. Efluentepapeleiro.
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