Synergistic Remediation of Pb and Cd Contaminated Soil with Modified Sludge and Ryegrass

This study applied high-temperature acidification to modify aluminum-based water treatment residual sludge and assessed its effects on the remediation of soil contaminated with lead (Pb) and cadmium (Cd) for growing ryegrass, and investigated the long-term stability of the remediation. The study indicates that the application of modified wastewater treatment residuals (M-WTRs) significantly enhanced the remediation process, achieving reductions in the concentrations of Pb and Cd in the contaminated soil by 56.38% and 58.91%, respectively. Furthermore, the M-WTRs successfully reduced the bioavailability of Pb and Cd in the soil. The study also demonstrates that the modified sludge maintained its remediation efficacy over an extended period, withstanding a simulated rainfall environment equivalent to 70.5 years. Overall, the synergistic remediation technology of M-WTRs and ryegrass has great potential in the remediation of Cd and Pb contaminated soil.