Advances in Sustainable Soil Health Restoration through Chemical Biological Physical Integrated and Nano Remediation Techniques

Land degradation, caused by pollution, salinization, erosion, and nutrient loss, undermines food security, the resilience of climate systems, and the health of ecosystems. This review provides an assessment of distinct advanced techniques used for soil remediation which include chemical, biological, physical, integrated, and nano remediation. Some chemical methods like gypsum reclamation, electrokinetic remediation, and advanced oxidation processes (AOPs) focus on the mobilization and breakdown of contaminants, achieving high removal efficiencies epitomized by heavy metals and organics. Other methods, such as phytoremediation, bioaugmentation, and mycoremediation, enhance soil fertility and employ restorational biology while inventive methods like Microbially-Induced Calcite Precipitation (MICP) bolster soil strength. Some of the physical processes are soil flushing and thermal desorption which can efficiently remove pollutants, but energy costs are high. Integrated techniques, notably the application of biochar and electro-bioremediation, demonstrate synergistic enhancement with soil structure and bioremediation performance. Nano-remediation provides unparalleled efficiency for pollutant removal but using nano-zero valent iron (nZVI), nanoclays, and graphene oxide (GO) poses unchartered ecological threats. From the comparison, it is clear that the sustainable remedial approach requires a multifaceted hybrid methodology tailored to the specific site conditions.