Algal Sweeper: A Bio-Mechanical Sweeper System for Sustainable Mitigation of Algal Blooms in Waterbodies

Harmful algal blooms (HABs pose significant threats to aquatic ecosystems, public health, and local economies, while existing mitigation strategies often rely on reactive chemical treatments that can produce long-term ecological impacts. This study presents the design, development, and laboratory evaluation of a scalable bio-mechanical Sweeper system for proactive surface-water algal remediation. The system consists of a semi-hexagonal, perforated Sweeper structure fabricated from recycled plastic and integrated with sustainable barley straw filtration media, mounted on an underwater remotely operated vehicle (ROV) for controlled deployment. Hydrodynamic optimization of the Sweeper geometry reduced drag force by approximately 86% relative to an initial flat-plate design, improving structural durability and filtration efficiency. Laboratory testing conducted in a pond simulator demonstrated effective mechanical removal of surface algae and suppression of algal growth over a 3-day period, attributed to low concentrations of hydrogen peroxide released during barley straw decomposition. The ROV-mounted Sweeper enabled continuous surface filtration and remote monitoring via onboard imaging. Results indicate that the proposed system provides an environmentally responsible alternative to chemical algaecides and has strong potential for scalable field deployment. This bio-mechanical approach offers a proactive strategy for HAB mitigation, supporting long-term water quality management and ecosystem protection.