CHENNAI: A recent study by Anna University’s Centre for Environmental Studies has identified bioearth as a promising and sustainable solution for restoring degraded forest lands in Tamil Nadu. According to the study, it accounts for 30 to 40 per cent of the total waste found in older landfill sites.
Bioearth is a fine, soil-like material generated through the long-term decomposition of organic waste in dumpsites.
Led by Professor Dr S Kanmani, the 2025-research evaluated the physical, chemical and environmental properties of bioearth to determine its suitability for ecological restoration projects.
Researchers found that bioearth had several characteristics that supported plant growth, including adequate moisture retention and physical properties that promoted aeration and root development. The material also contained essential nutrients such as nitrogen, phosphorus and potassium. While nutrient levels were lower than those required for agricultural cultivation, the study found them sufficient for the growth of non-edible plants and tree species commonly used in afforestation programmes.
The study also examined the presence of heavy metals, including zinc, copper, nickel, chromium and lead. Although traces of these metals were detected, researchers reported that most concentrations remained within acceptable limits. Environmental risk assessments indicated low to moderate ecological risks, while human health assessments showed negligible risks when bioearth is handled using appropriate procedures.
Speaking to DT Next, Dr Kanmani said, “Bioearth can be utilised in afforestation, wasteland reclamation and forest regeneration initiatives. Landfill sites, including areas such as Kodungaiyur, can be transformed into green spaces using bioearth as a growth medium.”
The study recommended further research on heavy metal removal, long-term environmental monitoring and pilot afforestation projects across different climatic regions. Researchers emphasised that integrating bioearth into restoration programmes could support sustainable waste management while contributing to ecological recovery and environmental conservation efforts across the state.