Feasibility of modifying the washout water weir on dyna sand filters performance

Abstract

Abstract Among the available technologies, the dyna-sand filter has gained attention due to its continuous filtration and sand washing mechanism, which provides an advantage in maintaining stable operation. Nevertheless, its performance under variable heights of washout weir with constant solid loads and the optimization of its washing system remain areas that require further study. This study investigates the use of the dyna-sand filter in water treatment facilities, focusing on the alteration of the washout weir to improve efficiency and reduce washout water amount. The study evaluates the filter’s performance under fixed influent total suspended solids (TSS) concentration and constant filtration rate (ROF), aiming to demonstrate the advantages of this alteration in enhancing removal efficiency, operational stability, and water saving through a laboratory-scale pilot. The average washout discharge fell from 0.788 to 0.486 L/min, a 38.3% reduction in washout water amount. As a result, filtered water production rose by nearly 2.2%, indicating more efficient hydraulic operation. These findings confirm that raising the washout weir by 4 cm improved filtration and reduced washout water loss. This, in turn, enhanced system productivity and the quality of washwater produced, assuming a consistent flow rate and solid load.