Phytoremediation of diesel contaminated soil using urban wastewater and its effect on soil concentration and plant growth

To assess the ability of tall fescue (Festuca arundinacea) and grass pea (Lathyrus sativus) plant species to effect phytoremediation with the utilization of freshwater and urban wastewater, greenhouse experiments were conducted in 2018 and 2019 with three levels of diesel contamination of 0, 1.5, and 3% w/w (referred to as DC (clean soil), D1.5 and D3, respectively). The maximum soil diesel content removal for tall fescue was by freshwater (54% (2018); 46% (2019)) and in the grass, the pea was by wastewater (44% (2018); 41% (2019)). A significant difference was observed in the amount of diesel removal by the plants at two levels of contamination, but the type of irrigation water had no significant effect. The plant growth decreased significantly by increased diesel in all treatments except D1.5 for tall fescue (2018) that led to better growth compared to the DC treatment. Diesel concentration had significant effects on plant parameters (dry weight, height, color, time of flowering, and podding), but the type of water had no similar impact. Phytoremediation was considered an effective method to reduce soil contamination, but treated wastewater could not significantly improve phytoremediation performance. The correlation coefficient indicated that the diesel removal rate was positively correlated with plant height and shoot dry weight (p < 0.01).HIGHLIGHTSThe use of tall fescue and grass pea was effective in reducing soil contamination.;Treated wastewater and freshwater had a similar effect on phytoremediation.;The low concentration of diesel increased tall fescue growth due to the sulfur content.;The diesel removal rate was positively correlated with shoot dry weight.;