Desempenho de um decantador de leito móvel na remoção de sólidos finos de água sintética
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Data
2023-02-24
Autores
Chaves, Luiza Gervazio
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Universidade Estadual Paulista (Unesp)
Resumo
A entrada de diversos poluentes nos corpos d’água têm gerado cada vez mais debates acerca da otimização de processos de tratamentos. A dificuldade do tratamento é avaliada pelos poluentes presentes na água bruta ou esgoto, sendo premissa na definição do sistema que tenha melhor custo-benefício e que assegure a qualidade final da água tratada. Um dos principais problemas nas estações de tratamento de esgoto são a entrada de partículas finas de areia e argila que adentram nas etapas subsequentes do tratamento, são frequentes e causam prejuízos ao processo. Dessa forma, essa pesquisa buscou avaliar a utilização de meio suporte em um decantador de fluxo ascendente para remoção de partículas finas. O sistema consistiu em um tanque de agitação de 2.000 L, que compreendia em seu interior um agitador de 184 Watt, um medidor de vazão tipo rotâmetro e uma bomba submersível de 368 Watt, o sistema de entrada, o decantador com meio suporte e a calha coletora, além de um reservatório de 2.000 L para coleta da água tratada. Foram executados ensaios com dois tipos de água sintética com concentrações médias de sólidos totais (ST) de 276 mg/L na água sintética tipo I e de 394 mg/L na água sintética tipo II e turbidez média de 13 NTU na água sintética tipo I e 194 NTU na água sintética tipo II. O decantador operou em cinco configurações: sem meio suporte e em diferentes empacotamentos do leito, sendo 25%, 50% e 75% como leito móvel e 100% configurando leito fixo. Os parâmetros utilizados para avaliar o efeito da altura de meio suporte na remoção de partículas foram a turbidez e os sólidos totais. Os resultados de eficiência média de remoção da turbidez dos ensaios com a água sintética tipo I foram de 2,2% no leito sem meio suporte, 24,3% no leito com 25% de enchimento, com empacotamento de 50%, 75% e 100% do meio suporte no leito foi observada eficiência média de 19,3%, 15,6% e 27,1%, nessa sequência. A eficiência média de remoção de turbidez da água sintética tipo II no leito sem meio suporte e com enchimento do leito em 0,25 m, 0,50 m, 0,75 m e 1,0 m foi de 31,7%, 41,3%, 41,1%, 39,9% e 36,8%, respectivamente. Por sua vez, a eficiência média de remoção de sólidos totais da água sintética tipo I apresentou 21,2% sem meio suporte, enquanto que o leito com empacotamento de meio suporte em 25%, 50%, 75% e 100% mostrou 14,7%, 21,5%, 24,2% e 12,9%, nessa ordem. Ademais, as amostras de sólidos totais da água sintética tipo II apresentaram eficiência média de remoção ao longo do ensaio no leito sem meio suporte em 28,8%, enquanto 36,6%, 62,9%, 46,9% e 40,2% foram obtidos nos leitos com 25%, 50%, 75% e 100% de empacotamento, respectivamente. O decantador apresentou remoção de sólidos totais e turbidez em todas as configurações com meio suporte no leito, sendo o melhor desempenho obtido em 50% de empacotamento.
The infiltration of diverse pollutants into water bodies has led to an increasing debate on the optimization of treatment processes. The complexity of the treatment process is evaluated by the type of pollutants present in the raw water or sewage, which is a prerequisite for determining the system that is the most cost-effective and ensures the final quality of the treated water. One of the major challenges in sewage treatment plants is the entry of fine particles of sand and clay, which penetrate subsequent treatment stages, are widespread, and impair the process. Therefore, this research aimed to investigate the use of a support material in an upward flow settler for eliminating fine particles. The system was comprised of a 2,000 L agitation tank equipped with a 184 Watt agitator, a rotameter flow meter, and a 368 Watt submersible pump, an inlet system, a settler with a support material, a collecting channel, and a 2,000 L reservoir for collecting the treated water. The tests were conducted with two types of synthetic water, which had an average concentration of total solids (TS) of 276 mg/L in synthetic water type I and 394 mg/L in synthetic water type II, as well as an average turbidity of 13 NTU in synthetic water type I and 194 NTU in synthetic water type II. The settler was operated in five configurations, including without a support material and with different bed packings at 25%, 50%, and 75% as a moving bed, and 100% as a fixed bed. The parameters used to evaluate the effect of support material height on particle removal were turbidity and total solids. The average results of turbidity removal efficiency for tests with synthetic water type I were 2.2% in the bed without support material, 24.3% in the bed with 25% filling, and an average efficiency of 19.3%, 15.6%, and 27.1% were observed with 50%, 75%, and 100% support material filling in the bed, respectively. The average turbidity removal efficiency of synthetic water type II in the bed without support material and with bed filling at 0.25 m, 0.50 m, 0.75 m, and 1.0 m was 31.7%, 41.3%, 41.1%, 39.9%, and 36.8%, respectively. Moreover, the average total solids removal efficiency of synthetic water type I was 21.2% without support material, while the bed with support material packing at 25%, 50%, 75%, and 100% showed 14.7%, 21.5%, 24.2%, and 12.9%, respectively. The samples of total solids from synthetic water type II showed an average removal efficiency throughout the test in the bed without support material at 28.8%, while 36.6%, 62.9%, 46.9%, and 40.2% were obtained in beds with 25%, 50%, 75%, and 100% packing, respectively. The settler demonstrated total solids and turbidity removal in all configurations with support material in the bed, and the best performance was achieved with 50% packing.
The infiltration of diverse pollutants into water bodies has led to an increasing debate on the optimization of treatment processes. The complexity of the treatment process is evaluated by the type of pollutants present in the raw water or sewage, which is a prerequisite for determining the system that is the most cost-effective and ensures the final quality of the treated water. One of the major challenges in sewage treatment plants is the entry of fine particles of sand and clay, which penetrate subsequent treatment stages, are widespread, and impair the process. Therefore, this research aimed to investigate the use of a support material in an upward flow settler for eliminating fine particles. The system was comprised of a 2,000 L agitation tank equipped with a 184 Watt agitator, a rotameter flow meter, and a 368 Watt submersible pump, an inlet system, a settler with a support material, a collecting channel, and a 2,000 L reservoir for collecting the treated water. The tests were conducted with two types of synthetic water, which had an average concentration of total solids (TS) of 276 mg/L in synthetic water type I and 394 mg/L in synthetic water type II, as well as an average turbidity of 13 NTU in synthetic water type I and 194 NTU in synthetic water type II. The settler was operated in five configurations, including without a support material and with different bed packings at 25%, 50%, and 75% as a moving bed, and 100% as a fixed bed. The parameters used to evaluate the effect of support material height on particle removal were turbidity and total solids. The average results of turbidity removal efficiency for tests with synthetic water type I were 2.2% in the bed without support material, 24.3% in the bed with 25% filling, and an average efficiency of 19.3%, 15.6%, and 27.1% were observed with 50%, 75%, and 100% support material filling in the bed, respectively. The average turbidity removal efficiency of synthetic water type II in the bed without support material and with bed filling at 0.25 m, 0.50 m, 0.75 m, and 1.0 m was 31.7%, 41.3%, 41.1%, 39.9%, and 36.8%, respectively. Moreover, the average total solids removal efficiency of synthetic water type I was 21.2% without support material, while the bed with support material packing at 25%, 50%, 75%, and 100% showed 14.7%, 21.5%, 24.2%, and 12.9%, respectively. The samples of total solids from synthetic water type II showed an average removal efficiency throughout the test in the bed without support material at 28.8%, while 36.6%, 62.9%, 46.9%, and 40.2% were obtained in beds with 25%, 50%, 75%, and 100% packing, respectively. The settler demonstrated total solids and turbidity removal in all configurations with support material in the bed, and the best performance was achieved with 50% packing.
Descrição
Palavras-chave
Decantação, Meio suporte, Partículas finas, Sólidos Totais, Turbidez, Fine particles, Settling, Support material, Total solids, Turbidity