Treatment of Domestic Wastewater Using Free Floating Constructed Wetlands Assisted by Eichhornia crassipes and Pistia stratiotes

Abstract

Floating phytoremediation offers a feasible, ecofriendly, and economically viable method for treating wastewater. The objective of this study was to assess the effectiveness of Eichhornia crassipes and Pistia stratiotes in treating domestic wastewater with varying initial strength at different hydraulic retention time (HRT). This was to find out a best treatment combination of macrophyte, wastewater strength and HRT by optimizing those parameters. The growth parameters of the plants were assessed and linked to the removal of contaminants. The wastewater phytoremediation by E. crassipes and P. stratiotes conducted for twenty-two days in a green house. Result showed that Eichhornia crassipes able to treat 50% strength of wastewater (50 WH) efficiently with removal of ammonia by 97.4%, phosphate by 68.5%, and COD by 54.0%, respectively, at the HRT of three days. The corresponding initial concentrations of ammonia, phosphate, and COD were likely to be 6.62 mg/L, 2.54 mg/L, and 37 mg/L, respectively. The 50WH experimental units showed the lowest relative growth rate (RGR). The results proved the higher efficiency of E. crassipes in treating the domestic wastewater.