Integration of Composting and Vermicomposting Bioprocesses Enables the Treatment of Tobacco Waste and Improves the Quality of Final Inputs

The environmentally safe management of nicotine-rich tobacco waste remains a major challenge, as incineration generates greenhouse gases and toxic emissions, while alternative valorization routes are often costly or technically constrained. Although composting and vermicomposting can mitigate toxicity and stabilize organic matter, evidence of their integrated application to tobacco waste remains limited. This study compared composting alone with an integrated strategy combining short pre-composting followed by vermicomposting to convert seized tobacco waste into agronomically valuable inputs. Three composting piles (200 kg each) were prepared with increasing tobacco waste content (0–50% w/w). Key physicochemical parameters (pH, electrical conductivity, volatile solids, total organic carbon, total nitrogen, C/N ratio) and degradation kinetics were monitored. Composting achieved adequate thermophilic exposure (> 55°C during days 14–22) and high organic matter stabilization, with maximum degradation > 64%. The integrated process markedly reduced phytotoxicity and increased the germination index (GI%) to 221% at a 1:99 (waste:water) dilution for the highest tobacco-content treatment. Principal component analysis indicated that vermicomposting shifted end-products toward more phytostimulant profiles than composting alone. Overall, integrating composting with vermicomposting provides a technically feasible, low-cost alternative to incineration, enabling the valorization of tobacco waste within a circular economy framework.