Efficiency of Salvinia molesta and Pistia stratiotes in Treatment of Industrial Wastewater

Abstract

Wastewater generation has grown to be a serious concern as a result of the current, extensive industrialization. The removal of pollutants from wastewater by chemical methods is very costly. Phytoremediation is a cost-effective, environmentally friendly technology that utilizes plants to immobilize, uptake, reduce or degrade the pollutants that are released into the environment. In this study, Salvinia molesta and Pistia stratiotes were utilized in the treatment of wastewater from an apparel industry for 18 days and reduction efficiencies of selected parameters in wastewater were evaluated. The pH of wastewater in the control and treatment tanks varied between 6.86±0.03 and 8.21±0.02. Electric Conductivity (EC) was reduced from 118.5±0.28 µS/cm to 98.55±0.46 µS/cm by P. stratiotes while there was a gradual increase of EC from 119.8±0.75 µS/cm to 136.6±0.21 µS/cm by S. molesta. Furthermore, P. stratiotes indicated higher percentage reductions of turbidity, TS, TDS and TSS (69.74%, 30.85%, 18.13% and 73.90%), compared to those of S. molesta. A higher reduction of percent nitrate was recorded in tanks with P. stratiotes (62.07%) in comparison to S. molesta and the control tanks. Also, a higher phosphate removal was recorded by P. stratiotes (87.00%) in comparison to S. molesta (49.47%). The reduction of Zn in treatment tanks with S. molesta and P. stratiotes were 22.89% and 17.87%, respectively. A higher Cu reduction was recorded in the tanks with S. molesta (52.47%) whereas, P. stratiotes indicated 42.37% Cu reduction efficiency. P. stratiotes indicated a higher Cd reduction percentage (29.97%) whereas S. molesta indicated 18.13% reduction. Bioconcentration factors (BCF) of Zn, Cd, Cu for S. molesta were 1.19, 0.74, 2.14, respectively and it was 0.78, 1.04, 1.38, respectively for P. stratiotes. The evidence presented by this study emphasized that Salvinia molesta and Pistia stratiotes are potential plants to treat wastewater from apparel industries.