Tertiary water treatment with Sargassum spp Filter: Pollutant hydraulic loss coefficient and removal capacity

Abstract

This study evaluates the hydraulic performance and pollutant removal efficiency of a tertiary water treatment system that uses a Sargassum spp. Filter, focusing on its application in water reuse systems. The primary objective was to establish a relationship between the local loss coefficient (K) and a normalized Reynolds number (Re_n) to better understand the hydraulic behaviour of the system under varying flow conditions. The K-Re_n relationship, adjusted with experimental data, was used as input in a numerical model developed in EPANET. The model accurately reproduced the experimental results, demonstrating the system's potential for small-scale water treatment applications. Results indicate that a sargassum filter can effectively treat a daily flow rate of 0.003 l/s (equivalent to a four-person household) with minimal energy loss. However, as the flow rate increased to 0.01 l/s, significant head losses (up to 4 m) were observed, resulting in a 74 % reduction in filtration efficiency. These findings underscore the importance of optimizing filter design and maintenance for scalability in community-level water treatment. This study highlights the potential of sargassum as a sustainable biofilter for improving water quality, while addressing challenges related to hydraulic performance and energy efficiency. Beyond its technical role, it promotes managing sargassum not as waste, but as a valuable resource. Treating it as harvestable biomass—like a marine fishery—can help mitigate coastal impacts and support local economies, aligning ecological management with sustainable water treatment.