Economic and performance optimization of hollow fiber forward osmosis using treated sewage effluent and novel sodium metasilicate sol-gel draw solution

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• Optimized forward osmosis using sodium metasilicate enhances water management. • Efficient FO process by eliminating the need for draw solution regeneration. • Achieved peak water flux of 17.82 LMH with optimized operational parameters. • Demonstrated significant reduction in specific solution cost to $0.16/m³. • Findings support sustainable agriculture in arid regions facing water scarcity. This study integrates performance optimization with an economic analysis of a hollow fiber forward osmosis (HFFO) system using a novel sodium metasilicate (SMS)-based sol-gel draw solution. The SMS sol-gel is diluted during the FO process using treated sewage effluent as the feed solution, addressing wastewater reuse challenges. Unlike conventional draw solutions requiring energy-intensive regeneration, the diluted SMS is directly applied for soil enhancement, eliminating regeneration needs. Optimized parameters include feed flow rates (60–80 L/h), draw flow rates (50–75 L/h), transmembrane pressure (0.2–0.3 bar), and a draw solution molarity of 0.3 M. The system achieved a peak water flux of 17.82 LMH in AL-DS orientation and an ion rejection rate of 97.8 %. Notably, the specific solution cost (SSC) varied between $0.16 and $0.37 per cubic meter, depending on operational parameters, with the optimized system achieving the lowest SSC of $0.16 per cubic meter, demonstrating significant cost-effectiveness and sustainability.