Influência da placa difusora na remoção de sólidos suspensos totais em filtro de areia pressurizado

Abstract

The removal efficiency of sand filters, used in localized irrigation, varies according to the operating conditions and the characteristics of the filter medium, with differences in solid retention between the superficial and deep layers. Studies have shown that different diffuser plate models cause changes in the behavior of the water flow lines in the filtration process, altering the hydraulic behavior and the turning of the surface layer of the filtering bed, relating to the development of preferential paths for the passage of water, which can influence the ability of filters to remove suspended solids In this context, the present work aimed to evaluate the influence of different diffuser plate models combined with different filtration rates and filtering layer heights, on the efficiency of removal of total suspended solids using a commercial sand filter. The work was divided into two parts. The first aimed to evaluate the hydraulic behavior of the equipment's filtration process and the turning of the surface layer of the filtering bed, combining two filtering bed heights and seven filtration rates, using water without suspended solids. The second part aimed to evaluate the removal efficiency of the filter filtration process using two filter layer heights and two filtration rates. In both parts, silica sand was used as a filter medium. The sand filter filtration process using the proposed diffuser plate showed the lowest pressure losses when using the empty filter when compared to the original diffuser plate, however, when using a filter bed, a reduction in the difference in pressure loss between the evaluated plates was observed. , where the proposed plate caused greater losses relative to the filtering layer. Additionally, there was no difference in the turning of the surface layer for the evaluated treatments. Regarding the removal efficiency, the evaluation methods presented similar results, showing that a larger sampling of the water leads to more reliable results. The proposed diffuser plate had greater removal efficiency when using the lowest filtering layer height and lowest filtration rate, whereas for the original plate it was at the highest layer height and highest filtration rate. In general, the constructive model of the diffuser plate influences both the hydraulic behavior and the efficiency of removal of suspended solids contained in the water in the filtration process, where its dimensioning must take into account the physical characteristics of the filtering layer and the operating conditions in order to achieve satisfactory results.