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Abstract(s)
O presente trabalho teve como principais objectivos, estudar e optimizar o processo de
tratamento do efluente proveniente das máquinas da unidade Cold-press da linha de
produção da Empresa Swedwood, caracterizar a solução límpida obtida no tratamento e
estudar a sua integração no processo, e por fim caracterizar o resíduo de pasta de cola
obtido no tratamento e estudar a possível valorização energética deste resíduo.
Após caracterização inicial do efluente e de acordo com os resultados de um estudo
prévio solicitado pela Empresa Swedwood a uma empresa externa, decidiu-se iniciar o
estudo de tratabilidade do efluente pelo processo físico-químico a coagulação/floculação.
No processo de coagulação/floculação estudou-se a aplicabilidade, através de ensaios
Jar-test, dos diferentes agentes de coagulação/floculação: a soda cáustica, a cal, o cloreto
férrico e o sulfato de alumínio. Os melhores resultados neste processo foram obtidos com a
adição de uma dose de cal de 500 mg/Lefluente, seguida da adição de 400 mg/Lefluente de
sulfato de alumínio. Contudo, após este tratamento o clarificado obtido não possuía as
características necessárias para a sua reintrodução no processo fabril nem para a sua
descarga em meio hídrico. Deste modo procedeu-se ao estudo de tratamentos
complementares.
Nesta segunda fases de estudo testaram-se os seguintes os tratamentos: a oxidação
química por Reagente de Fenton, o tratamento biológico por SBR (sequencing batch
reactor) e o leito percolador. Da análise dos resultados obtidos nos diferentes tratamentos
conclui-se que o tratamento mais eficaz foi o tratamento biológico por SBR com adição de
carvão activado.
Prevê-se que no final do processo de tratamento o clarificado obtido possa ser
descarregado em meio hídrico ou reintroduzido no processo. Como o estudo apenas foi
desenvolvido à escala laboratorial, seria útil poder validar os resultados numa escala piloto
antes da sua implementação industrial.
A partir dos resultados do estudo experimental, procedeu-se ao dimensionamento de
uma unidade de tratamento físico-químico e biológico à escala industrial para o tratamento
de 20 m3 de efluente produzido na fábrica, numa semana. Dimensionou-se ainda a unidade
(leito de secagem) para tratamento das lamas produzidas.
Na unidade de tratamento físico-químico (coagulação/floculação) os decantadores
estáticos devem possuir o volume útil de 4,8 m3. Sendo necessários semanalmente 36 L da
suspensão de cal (Neutrolac 300) e 12,3 L da solução de sulfato de alumínio a 8,3%. Os
tanques de armazenamento destes compostos devem possuir 43,2 litros e 96 litros,
respectivamente. Nesta unidade estimou-se que são produzidos diariamente 1,4 m3 de
lamas. Na unidade de tratamento biológico o reactor biológico deve possuir um volume útil de
6 m3. Para que este processo seja eficaz é necessário fornecer diariamente 2,1 kg de
oxigénio. Estima-se que neste processo será necessário efectuar a purga de 325 litros de
lamas semanalmente. No final da purga repõe-se o carvão activado, que poderá ser
arrastado juntamente com as lamas, adicionando-se 100 mg de carvão por litro de licor
misto.
De acordo com o volume de lamas produzidos em ambos os tratamentos a área mínima
necessária para o leito de secagem é de cerca de 27 m2.
A análise económica efectuada mostra que a aquisição do equipamento tem o custo de
22.079,50 euros, o custo dos reagentes necessários neste processo para um ano de
funcionamento tem um custo total de 508,50 euros e as necessidades energéticas de
2.008,45 euros.
This study had as its primary goals to study and optimize the wastewater treatment process from the Cold-press unit from the production line of the Swedwood Company; characterize the clear solution obtained in the treatment and study its integration process; and, finally, characterize the residual glue paste obtained in the treatment and study the possible energy recovery of waste. After initial characterization of the wastewater and in accordance with the results of a previous study requested by the Swedwood Company to an outside company, one decided to launch the study of treatability of wastewater by physicochemical process coagulation/flocculation. In the coagulation /flocculation process one studied the applicability through Jar-test experiments, of the various agents of coagulation/flocculation: sodium hydroxide, lime, ferric chloride and aluminum sulfate. The best results were obtained in this process with the addition of a lime dose of 500 mg/Leffluent, followed by the addition of 400 mg/Leffluent of aluminum sulfate. However, after this treatment the clarification obtained lacked the necessary characteristics for its reintroduction in the manufacturing process or to its discharge into the aquatic environment. Thus, one proceeded to the study of complementary treatments. In this second phase of the study one tested the following treatments: chemical oxidation by Fenton reagent, biological treatment by sequencing batch reactor (SBR) and the trickle filter. From the analysis of the results obtained in different treatments one concluded that the most effective treatment was the biological treatment by SBR with addition of activated carbon. It is expected that at the end of the treatment process the clarified obtained can be discharged into the aquatic environment or reintroduced into the manufacturing process. Since the study was conducted only in laboratory scale, it would be useful to validate the results in a pilot scale before its industrial implementation. From the results of the experimental study, one proceeded to the design of a unit of physical-chemical and biological to the industrial scale to treat 20 m3 of wastewater produced at the plant in a week. It is also scaled to unit (drying bed) for treatment of sludge produced. In the physical-chemical treatment unit (coagulation/flocculation) the static clarifiers must have the usable volume of 4.8 m3. Being 36 L weekly required of the suspension of lime (Neutrolac 300) and 12.3 L of aluminum sulfate solution at 8.3%. The storage tanks of these compounds should have 43.2 liters and 96 liters respectively. This unit has been estimated to produce daily 1.4 m3 of sludge. In the biological treatment unit, the biological reactor must have a working volume of 6 m3. For this process to be effective one must provide daily 2.1 kg of oxygen. It is estimated that at the end of the week a purge of 325 liters of sludge should be carried out. Afther the purge one replaces the activated carbon, which may be dragged along with the sludge, adding 100 mg of activated carbon per liter of mixed liquor. According to the volume of sludge produced in both treatments the minimum area needed for the bed is about 27 m2. It is estimated to be recovered 0.54 m3 of water. This water is recovered and introduced into the treatment process. The economic analysis shows that the acquisition of equipment will cost 22,079.50 euros, the cost of reagents required in this process to one year in operation has a total cost of 508.50 euros and the energy needs of 2,008.45 euros.
This study had as its primary goals to study and optimize the wastewater treatment process from the Cold-press unit from the production line of the Swedwood Company; characterize the clear solution obtained in the treatment and study its integration process; and, finally, characterize the residual glue paste obtained in the treatment and study the possible energy recovery of waste. After initial characterization of the wastewater and in accordance with the results of a previous study requested by the Swedwood Company to an outside company, one decided to launch the study of treatability of wastewater by physicochemical process coagulation/flocculation. In the coagulation /flocculation process one studied the applicability through Jar-test experiments, of the various agents of coagulation/flocculation: sodium hydroxide, lime, ferric chloride and aluminum sulfate. The best results were obtained in this process with the addition of a lime dose of 500 mg/Leffluent, followed by the addition of 400 mg/Leffluent of aluminum sulfate. However, after this treatment the clarification obtained lacked the necessary characteristics for its reintroduction in the manufacturing process or to its discharge into the aquatic environment. Thus, one proceeded to the study of complementary treatments. In this second phase of the study one tested the following treatments: chemical oxidation by Fenton reagent, biological treatment by sequencing batch reactor (SBR) and the trickle filter. From the analysis of the results obtained in different treatments one concluded that the most effective treatment was the biological treatment by SBR with addition of activated carbon. It is expected that at the end of the treatment process the clarified obtained can be discharged into the aquatic environment or reintroduced into the manufacturing process. Since the study was conducted only in laboratory scale, it would be useful to validate the results in a pilot scale before its industrial implementation. From the results of the experimental study, one proceeded to the design of a unit of physical-chemical and biological to the industrial scale to treat 20 m3 of wastewater produced at the plant in a week. It is also scaled to unit (drying bed) for treatment of sludge produced. In the physical-chemical treatment unit (coagulation/flocculation) the static clarifiers must have the usable volume of 4.8 m3. Being 36 L weekly required of the suspension of lime (Neutrolac 300) and 12.3 L of aluminum sulfate solution at 8.3%. The storage tanks of these compounds should have 43.2 liters and 96 liters respectively. This unit has been estimated to produce daily 1.4 m3 of sludge. In the biological treatment unit, the biological reactor must have a working volume of 6 m3. For this process to be effective one must provide daily 2.1 kg of oxygen. It is estimated that at the end of the week a purge of 325 liters of sludge should be carried out. Afther the purge one replaces the activated carbon, which may be dragged along with the sludge, adding 100 mg of activated carbon per liter of mixed liquor. According to the volume of sludge produced in both treatments the minimum area needed for the bed is about 27 m2. It is estimated to be recovered 0.54 m3 of water. This water is recovered and introduced into the treatment process. The economic analysis shows that the acquisition of equipment will cost 22,079.50 euros, the cost of reagents required in this process to one year in operation has a total cost of 508.50 euros and the energy needs of 2,008.45 euros.
Description
Keywords
Efluente Tratamento biológico Coagulação/floculação Tratamento primário SBR Wastewater Biological treatment Coagulation/flocculation Primary treatment
Citation
Publisher
Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto