Influence of the diffuser plate construction design on the filtration hydraulic behaviour in a pressurized sand filter

Studies have shown that the design of pressurised sand filters diffuser plates influences deformation of the filtering layer surface which leads to changes in its hydraulic behaviour which may interfere with the removal capacity of the equipment. Based on this perspective, this study aims to evaluate the influence of the diffuser plate constructive design on filter hydraulic behaviour and on the deformation of the filtering layer surface for a commercial pressurised sand filter design for different combinations of filter layer height and filtration rate. The objective was to evaluate different filter layer heights to verify the influence of the proximity of the filter layer to the diffuser plate on surface deformation and, consequently, on pressure loss during the filtration process. The objective of this study was to evaluate the possibility of using a diffuser plate designs developed using computational fluid dynamics, adapted to the dimensions of a commercial sand filter design. An experiment was conducted in a hydraulic module built in a closed circuit of water circulation using public water supply. Two diffuser plate designs were evaluated, combined with two filter layer heights and seven filtration rates. The pressure loss produced by the original diffuser plate in the empty filter condition showed the highest values for all filtration rates evaluated. However, when a sand filter was filled with a filter layer, apparently similar behaviour was observed in relation to the proposed diffuser plate design, indicating the influence of the diffuser plate model on the hydraulic behaviour of the equipment. The deformation of the filtering layer surface occurred with all the diffuser plate designs evaluated, and differentiation between the designs was not evident. The adaptation of a diffuser plate sized under specific conditions achieved better results than the original diffuser plate, although it did not achieve the same result as reported in the original research on the plate.& COPY; 2023 IAgrE. Published by Elsevier Ltd. All rights reserved.