Integrating Seasonal Dynamics and Wastewater Treatment with Biomass Production of Lemna gibba L. for Sustainable Water Remediation

Duckweed (Lemna gibba L.) is an eco-friendly aquatic macrophyte with significant potential for wastewater treatment and biomass valorization. This study evaluated its nutrient removal efficiency and growth performance under controlled greenhouse conditions using agricultural (AG) and domestic sewage (SG) wastewater at five dilution levels across three seasons. Growth and biochemical responses were monitored over 180 days. Results demonstrated that L. gibba effectively removed anions (NO₃⁻, PO₄³-, Cl-, SO₄²⁻) and cations (Ca²⁺, Mg²⁺, K⁺, Na⁺), with higher removal efficiencies in AG wastewater than in SG, except for Cl- and SO₄²⁻, which were more efficiently removed from SG. Biomass production peaked at 75% wastewater concentration (T3), with fresh weight increases of 133% (AG) and 146% (SG), while dry weight gains were comparable (AG 187%, SG 185%). Relative growth rate and crop growth rate were significantly affected by seasonality, with the second season (S2) showing the highest productivity. Biochemical analyses revealed higher protein yields in SG and slightly greater carbohydrate yields compared to AG. Generally, L. gibba exhibited strong phytoremediation capacity and produced nutrient-enriched biomass suitable for aquaculture or bioresource applications. These results support its use as a cost-effective and sustainable approach for reorganized wastewater treatment and resource recovery.