Field performance evaluation of a fibrous barrier system for algae and odor compound reduction: A temporal comparison study

The increasing prevalence of harmful algal blooms (HABs) in aquatic environments poses a significant threat to water quality. This study evaluates an innovative, sustainable algae-blocking technology employing a fibrous ciliary composite mat for effective algae control in reservoirs. The system is designed for passive operation, utilizing the natural suction force of water intake to capture and remove algae without chemical treatments. Odor-causing compounds, such as geosmin and 2-methylisoborneol (2-MIB), are produced by algae and anaerobic microorganisms and can affect the taste and odor of tap water even at trace levels (ng/L), making them key monitoring targets. These two compounds were selected as representative odor-causing compounds and their removal efficiency was analyzed. This technology targets the pretreatment of raw water entering a water treatment plant. This technology removes algae before they reach the water treatment plant, minimizing the release of taste and odor-causing compounds due to algal bursts and reducing the load on subsequent water treatment processes. Field demonstrations conducted in 2017 and 2024 evaluated the efficacy of this technology in reducing algal biomass and off-flavor compounds. The results demonstrated chlorophyll a removal efficiencies of 37.6 ± 6.0% in 2017 and 52.7 ± 10.9% in 2024, while geosmin removal efficiencies of 38.5 ± 0.2% in 2017 and 42.5 ± 11.3% in 2024, demonstrating long-term operational efficiency. These results demonstrate the potential of this low-energy, cost-effective technology as a durable and effective solution for mitigating the impacts of HABs. • Field demonstrations from 2017 to 2024 confirmed that the technology maintained or improved its performance after seven years of operation. • Chlorophyll a removal efficiency was measured at 37.6 ± 6.0% and 52.7 ± 10.9% in 2024, and geosmin removal efficiency was measured at 38.5 ± 0.2% and 42.5 ± 11.3% in 2017 and 2024, respectively. • The higher the algae concentration, the higher the removal efficiency tended to be. • This technology provides a non-powered and cost-effective algal bloom mitigation solution, laying the foundation for future development of sustainable algal bloom control methods.