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Advisor(s)
Abstract(s)
A lavagem dos filtros utilizados na clarificação da água de piscinas públicas é um
processo extremamente importante na manutenção da qualidade da água, necessária para
o bem-estar dos utilizadores. No entanto, este processo representa um custo significativo,
uma vez que, para além da água necessária para a lavagem, que é geralmente água da
própria piscina, a água de reposição encontra-se a uma temperatura inferior à água da
piscina, o que implica custos energéticos para o aquecimento da mesma. O consumo de
água para lavagem dos filtros situa-se normalmente na ordem dos 1,5% da água tratada,
podendo mesmo chegar aos 3%.
Tendo como base alguns estudos já efetuados na área de tratamento de águas de
piscinas, este trabalho tem como objetivo o reaproveitamento parcial da água de lavagem
desses mesmos filtros, utilizando para isso o processo de separação por osmose inversa,
efetuando uma caracterização química e física exaustiva das amostras antes, durante e
após o processo de separação.
Dos ensaios efetuados com caracterização completa das amostras, os resultados
obtidos bastante satisfatórios, atingindo-se grandes reduções da quantidade de
contaminantes presentes na água de lavagem dos filtros. Todos os parâmetros físicoquímicos
analisados encontram-se dentro dos limites especificados na legislação em vigor,
nomeadamente o carbono orgânico dissolvido, a condutividade, os cloretos e os
trihalometanos, permitindo a reutilização do permeado obtido na separação por osmose
inversa, com uma taxa de recuperação de água de 64,3%. A taxa de rejeição de sais foi de
95,9 e 93,4% para o sódio, 70,4 e 82,7% para os trihalometanos e >96,9 e >90,1% para os
cloretos, para o primeiro e segundo ensaio final apresentado, respetivamente.
Efetuou-se ainda um estudo aproximado relativamente à economização de água de
reabastecimento e ao consumo de energia para aquecimento da mesma, estimando-se uma
redução de 1737 €/ano no gasto com o consumo de água da rede pública e uma redução de
55 kWh no consumo de energia, considerando uma piscina semiolímpica.
The washing of the filters used in the clarification of public swimming pools is an extremely important process for assuring an appropriate water quality, essential for the well being of bathers. However, it represents a significant cost, given that the water used for washing the filters is generally from the swimming pool itself. In addition, the reposition water is normally at a lower temperature than the pool water, which means that it must be heated, representing higher energy costs. The water consumption for the filter cleaning is about 1,5% of the treated water, although this value can reach 3%. Having a wide variety of studies published in the swimming pool water treatment subject as a background, this project has the purpose of partially reusing the filter backwash water from treated swimming pool water. With this purpose, a reverse osmosis process was chosen, and the samples were exhaustively analyzed before, during, and after the separation process. From the experiments made with complete characterization of the samples, the results obtained were very satisfactory, with a large reduction of the contaminants concentration, and taking the analyzed physical and chemical parameters to values under the regulated specifications, in particular the dissolved organic carbon, conductivity, chlorides and ttrihalomethanes, with a recovery rate of 64,3%. The salt rejection rate was 95,9 and 93,4% for sodium, 70,4 and 82,7% for trihalomethanes and >96,9 and >90,1% for chlorides, for the first and second final experiments presented, respectively. An approximate study regarding the water and energy consumption reduction was also made, anticipating an economy of 1737 €/year in public water consumption costs and a 55 kWh saving in energy consumption, taking in consideration a semi-olympic swimming pool.
The washing of the filters used in the clarification of public swimming pools is an extremely important process for assuring an appropriate water quality, essential for the well being of bathers. However, it represents a significant cost, given that the water used for washing the filters is generally from the swimming pool itself. In addition, the reposition water is normally at a lower temperature than the pool water, which means that it must be heated, representing higher energy costs. The water consumption for the filter cleaning is about 1,5% of the treated water, although this value can reach 3%. Having a wide variety of studies published in the swimming pool water treatment subject as a background, this project has the purpose of partially reusing the filter backwash water from treated swimming pool water. With this purpose, a reverse osmosis process was chosen, and the samples were exhaustively analyzed before, during, and after the separation process. From the experiments made with complete characterization of the samples, the results obtained were very satisfactory, with a large reduction of the contaminants concentration, and taking the analyzed physical and chemical parameters to values under the regulated specifications, in particular the dissolved organic carbon, conductivity, chlorides and ttrihalomethanes, with a recovery rate of 64,3%. The salt rejection rate was 95,9 and 93,4% for sodium, 70,4 and 82,7% for trihalomethanes and >96,9 and >90,1% for chlorides, for the first and second final experiments presented, respectively. An approximate study regarding the water and energy consumption reduction was also made, anticipating an economy of 1737 €/year in public water consumption costs and a 55 kWh saving in energy consumption, taking in consideration a semi-olympic swimming pool.
Description
Mestrado em Engenharia Química. Ramo optimização energética na indústria química
Keywords
Desinfeção Águas de piscinas Trihalometanos Osmose inversa Membrana Disinfection Swimming pool water Trihalomethanes Reverse osmosis Membrane
Citation
Publisher
Instituto Politécnico do Porto. Instituto Superior de Engenharia do Porto