Kinetic Assessment of Plant Growth and Pollutant Removal by Water Lettuce (Pistia Stratiotes L.) from Integrated Industrial Wastewater: A Lab-Scale Study

This study investigated the phytoremediation potential of water lettuce (Pistia stratiotes L.) for treating integrated industrial wastewater. Laboratory-scale experiments were conducted using three concentrations (0%, 50%, and 100%) of wastewater collected from the clustered industrial region of Haridwar, India. Plants were grown for 20 days under greenhouse conditions to understand pollutant reduction and biomass production through kinetic modeling approaches. The results showed that the maximum significant (p < 0.05) removal of pH (25.03%), electrical conductivity (89.25%), biochemical oxygen demand (92.81%), chemical oxygen demand (95.01%), calcium (90.93%), magnesium (85.85%), sodium (84.96), potassium (87.12%), total nitrogen (96.41%), and phosphorus (86.34%) were obtained using 50% concentration. The pollutant removal process followed a first-order reaction trend as indicated by good fitness (R², 0.85–0.99). Similarly, the plant growth attributes, i.e., fresh biomass, dry biomass, and total chlorophyll content, were also maximum in 50% concentration. The plant growth was simulated using logistic and modified Gompertz models and showed good fitness results (R² > 0.92). The highest relative growth rate of 2.045 mg g⁻¹d⁻¹ was also reported in 50% concentration. Therefore, the findings of this study contribute significantly to advancing the field of sustainable wastewater management by demonstrating the potential of P. stratiotes as an effective, low-cost, and eco-friendly phytoremediation agent for treating complex integrated industrial effluents. These results lay the groundwork for future large-scale applications and the development of green technologies aimed at mitigating industrial pollution sustainably.